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The activation of immune cells by targeting checkpoint inhibitors showed promising results with increased patient survival in distinct primary cancers. Since only limited data exist for human brain metastases, we aimed at characterizing tumor infiltrating lymphocytes (TILs) and expression of immune checkpoints in the respective tumors. Two brain metastases cohorts, a mixed entity cohort (n = 252) and a breast carcinoma validation cohort (n = 96) were analyzed for CD3+, CD8+, FOXP3+, PD-1+ lymphocytes and PD-L1+ tumor cells by immunohistochemistry. Analyses for association with clinico-epidemiological and neuroradiological parameters such as patient survival or tumor size were performed. TILs infiltrated brain metastases in three different patterns (stromal, peritumoral, diffuse). While carcinomas often show a strong stromal infiltration, TILs in melanomas often diffusely infiltrate the tumors. Highest levels of CD3+ and CD8+ lymphocytes were seen in renal cell carcinomas (RCC) and strongest PD-1 levels on RCCs and melanomas. High amounts of TILs, high ratios of PD-1+/CD8+ cells and high levels of PD-L1 were negatively correlated with brain metastases size, indicating that in smaller brain metastases CD8+ immune response might get blocked. PD-L1 expression strongly correlated with TILs and FOXP3 expression. No significant association of patient survival with TILs was observed, while high levels of PD-L1 showed a strong trend towards better survival in melanoma brain metastases (Log-Rank p = 0.0537). In summary, melanomas and RCCs seem to be the most immunogenic entities. Differences in immunotherapeutic response between tumor entities regarding brain metastases might be attributable to this finding and need further investigation in larger patient cohorts.
Die Felder und Techniken der modernen Fortpflanzungsmedizin sind im Laufe der Jahre weit fortgeschritten. Um dem Wunsch eines kinderlosen Ehepaares nach Nachwuchs nachzugehen, haben sich Methoden entwickelt, um diesen zu erfüllen. Hierbei haben sich die In-Vitro-Fertilisation und die daraus entwickelte Modifikation, die Intracytoplasmatische Spermieninjektion etabliert. Auch wenn die seit dem Jahre 2004 durchgeführten IVF-Geburten, aufgrund mangelnder Krankenkassenleistungen, entschieden gesunken sind und die kumulative Schwangerschaftsrate nach drei durchgeführten Embryotransfers maximal bei 50-70 % liegt, ist die In-Vitro-Fertilisation und mit ihr verwandten Intracytoplasmatischen Spermieninjektion (im Falle mangelnder Spermienqualität) neben der homologen und heterologen Insemination das älteste und das neuste reproduktionsmedizinische Verfahren, das zur Behandlung des unerfüllten Kinderwunsches eingesetzt wird. Des Weiteren haben sich die Präimplantations- und Pränataldiagnostik einen weit verbreiten Ruf verschafft, um Erbkrankheiten und Fehlentwicklungen des Embryos noch in frühester Entwicklungszeit aufzudecken. Dass hierbei der Embryo und das noch ungeborene Leben in eine Zwickmühle ethischer und rechtlicher Beurteilungen rutschen, scheint offensichtlich. Denn das seit 1990 in Kraft getretene Embryonenschutzgesetz regelt zwar weite Bereiche rund um den Schutz des Embryos, hinterlässt aber auch Lücken. Somit werden Rufe laut nach der Schaffung eines eigenen Fortpflanzungsmedizingesetzes, um die ungeregelten Aspekte der Fortpflanzungsmedizin zu klären [457]. Die rechtliche Lage der modernen Fortpflanzungsmedizin in Deutschland ist recht komplex. Für die vielen verschiedenen Methoden herrschen unterschiedlich rechtliche Regelungen. So wird zum Beispiel die In-Vitro-Fertilisation rechtlich anders geregelt als die Pränatal- und die Präimplantaionsdiagnostik. In Hinsicht auf die In-Vitro-Fertilisation dient als rechtliche Grundlage das Embryonenschutzgesetz, welches besagt, dass „bereits die befruchtete, entwicklungsfähige menschliche Eizelle vom Zeitpunkt der Kernverschmelzung an“ einem Embryo mit all seinen Rechten entspricht. Die Pränataldiagnostik stützt sich zum großen Teil auf die von der Bundesärztekammer verabschiedeten „Richtlinien zur pränatalen Diagnostik von Krankheiten und Krankheitsdispositionen“ sowie auf eine „Erklärung zum Schwangerschaftsabbruch nach Pränataldiagnostik“. In diesen Richtlinien wird darauf hingewiesen, dass zum einen das Lebensrecht des Ungeborenen, zum anderen die Handlungsfreiheit der Eltern in die jeweiligen Entscheidungen einbezogen werden muss. Die in Deutschland zwischen Zulassung und Nichtzulassung befindliche Präimplantationsdiagnostik beruft sich auf das Embryonenschutzgesetz, welches den Verbrauch von Embryonen verbietet, da nach dem Gesetz eine Blastomere einem ganzen Embryo gleichgestellt sei. Ebenso besagt das ESchG, dass eine Eizelle nur zum Zweck der Herbeiführung einer Schwangerschaft befruchtet werden darf, da aber die Präimplantationsdiagnostik die genetische Analyse beabsichtigt, steht dies in einem Widerspruch. Jedoch wird in und außerhalb von Europa der Umgang mit IVF, Präimplantations- und Pränataldiagnostik verschieden gehandhabt. Während sich Deutschland und Österreich für ein klares Verbot der Präimplantationsdiagnostik aussprechen, ist diese in Frankreich und Großbritannien grundsätzlich möglich. Wenn man sich die halachischen Grundlagen im Umgang mit der modernen Fortpflanzungsmedizin vor Augen führt, ist es im Kern der Status des Embryos, der Juden und Christen in zwei völlig verschiedene Richtungen laufen lässt. Die Halacha spricht von menschlichem Leben erst von der Geburt an und geht von mehreren unterscheidbaren Stadien in der Entwicklung des vorgeburtlichen Lebens im Mutterleib aus. Ganz anders die christliche Ethik, sie erkennt bereits dem Embryo die Schutzwürdigkeit menschlichen Lebens zu. Wenn das jüdische Recht die Schutzwürdigkeit eines Embryos nach der entscheidenden Frage differenziert, ob er jünger oder älter als vierzig Tage ist, wird deutlich, dass die IVF als grundsätzlich rechtmäßig gelten muss, da die Embryonen, die im Zuge jeder IVF zerstört oder weitergehend genutzt werden, keinen besonderen Schutz in Anspruch nehmen können. Ebenso fallen jene Vorgänge und Maßnahmen einer modernen PID in jenen Zeitraum von vierzig Tagen nach der Empfängnis, innerhalb dessen nach jahrtausendalter Einstellung des jüdischen Rechts noch kein menschliches Leben im Mutterleib existiert. Somit steht die Halacha einer begründeten PID nicht im Wege. Eine zweite große Kernaussage dieser Dissertation ist die, dass sich das jüdische Religionsgesetz (die Halacha), welche unter anderem die Anleitungen zum Umgang mit der modernen Reproduktionsmedizin liefert, stets darauf bedacht ist, neu ausgelegt zu werden. Die Halacha ist ein immerwährend andauernder Prozess von Erneuerung, welche sich den aktuellen und örtlichen Gegebenheiten kritisch anpassen muss. So auch der Umgang mit der modernen Fortpflanzungsmedizin, der einem immerwährenden Prozess von Erneuerungen unterlegen ist.
Candida albicans and Candida dubliniensis are pathogenic fungi that are highly related but differ in virulence and in some phenotypic traits. During in vitro growth on certain nutrient-poor media, C. albicans and C. dubliniensis are the only yeast species which are able to produce chlamydospores, large thick-walled cells of unknown function. Interestingly, only C. dubliniensis forms pseudohyphae with abundant chlamydospores when grown on Staib medium, while C. albicans grows exclusively as a budding yeast. In order to further our understanding of chlamydospore development and assembly, we compared the global transcriptional profile of both species during growth in liquid Staib medium by RNA sequencing. We also included a C. albicans mutant in our study which lacks the morphogenetic transcriptional repressor Nrg1. This strain, which is characterized by its constitutive pseudohyphal growth, specifically produces masses of chlamydospores in Staib medium, similar to C. dubliniensis. This comparative approach identified a set of putatively chlamydospore-related genes. Two of the homologous C. albicans and C. dubliniensis genes (CSP1 and CSP2) which were most strongly upregulated during chlamydospore development were analysed in more detail. By use of the green fluorescent protein as a reporter, the encoded putative cell wall related proteins were found to exclusively localize to C. albicans and C. dubliniensis chlamydospores. Our findings uncover the first chlamydospore specific markers in Candida species and provide novel insights in the complex morphogenetic development of these important fungal pathogens.
Ovarian cancer (OvCa) is the tumor with the most unfavourable prognosis among all gynaecological malignancies causing more than 6000 deaths per year in Germany alone. Patients with OvCa show symptoms at very advanced stages of tumor progression when the only available treatments consist on tumor debulking surgery and administration of platinum based chemotherapeutics and anthracyclins. There is an urgent need to develop new therapeutical strategies since the actual 5 year survival rate of OvCa patients does not exceed 20-40%.
Immunotherapy is a promising approach for treatment of ovarian cancer, since it has been observed that immunological parameters can influence the outcome of the patient. The aim of our research is to overcome tumor immune escape by counteracting the immunosuppressive mechanisms developed by the tumor. In particular, this work studies the influence of adenosine generated by the ectonucleotidases CD39 and CD73 in the tumor microenvironment. Cellular expression of CD39 and CD73 contributes to immunosupression as these ectonucleotidases convert immune-stimulatory extracellular ATP into immunosuppressive adenosine. This was primarily described as effector mechanism for regulatory T cells, but may also be important in the tumor microenvironment.
Having found that tumor cells from OvCa-patients express high levels of ATP-depleting ectonucleotidases CD39 and CD73 we set out to investigate a potential immunosuppressive mechanism via adenosine production in the tumor microenvironment. We could measure 30-60 times higher adenosine production by OvCa cell lines and ascites-derived cancer cells as compared to physiological normal conditions. To confirm this putative immune escape mechanism we investigated its effect on several immune cell populations. CFSE-based assays, for example, showed an inhibition of CD4+ T cell proliferation by OvCA cell-derived adenosine. In this context, we have further established an in-vitro assay, where OvCa cells modulate the function of macrophages towards a M2 or tumor associated (TAM) phenotype. Together with the phenotype modulation adenosine exerts chemotactic effects on human monocytes and is thus likely to attract myeloid precursor cells towards the tumor tissue. Moreover, in a microenvironment that is shaped by OvCa cells, human monocytes differentiate into M2 macrophages or TAMs which themselves express significant levels of the adenosine-generating ectonucleotidases CD39 and CD73.
Investigating the regulation of ectonucleotidase expression, we also observed that approaches clinically used to treat OvCa (namely application of doxorubicine or irradiation) influence CD73 and CD39 levels of OvCa and immune cells in vitro. In this study we show how this treatment-induced change in the ATP/adenosine ratio modulates the effector function of different immune cells. Furthermore, we investigate the potential benefit of clinically available small molecule inhibitors for CD39 and CD73 that could relieve immunosuppression in the tumor microenvironment especially in combination with common treatment regimes.
Breast cancer is the most common cancer among women worldwide. Every year, nearly 1.4 million new cases of breast cancer are diagnosed, and about 450.000 women die of the disease. Approximately 15-25% of breast cancer cases exhibit increased quantities of the trans-membrane receptor tyrosine kinase human epidermal growth factor receptor 2 (HER2) on the tumor cell surface. Previous studies showed that blockade of this HER2 proto-oncogene with the antibody trastuzumab substantially improved the overall survival of patients with this aggressive type of breast cancer. Recruitment of natural killer (NK) cells and subsequent induction of antibody-dependent cell-mediated cytotoxicity (ADCC) contributed to this beneficial effect. We hypothesized that antibody binding to HER2-positive breast cancer cells and thus ADCC might be further improved by synergistically applying two different HER2-specific antibodies, trastuzumab and pertuzumab. We found that tumor cell killing via ADCC was increased when the combination of trastuzumab, pertuzumab, and NK cells was applied to HER2-positive breast cancer cells, as compared to the extent of ADCC induced by a single antibody. Furthermore, a subset of \(CD44^{high}CD24^{low}HER2^{low}\) cells, which possessed characteristics of cancer stem cells, could be targeted more efficiently by the combination of two HER2-specific antibodies compared to the efficiency of one antibody. These in vitro results demonstrated the immunotherapeutic benefit achieved by the combined application of trastuzumab and pertuzumab. These findings are consistent with the positive results of the clinical studies, CLEOPATRA and NEOSPHERE, conducted with patients that had HER2-positive breast cancer. Compared to a single antibody treatment, the combined application of trastuzumab and pertuzumab showed a stronger ADCC effect and improved the targeting of breast cancer stem cells.
Mechanisms underlying therapy resistance of tumor cells include protein kinase Akt. Putative Akt targets include store-operated \(Ca^{2+}\)-entry (SOCE) accomplished by pore forming ion channel unit Orai1 and its regulator STIM1. We explored whether therapy resistant (A2780cis) differ from therapy sensitive (A2780) ovary carcinoma cells in Akt, Orai1, and STIM1 expression, \(Ca^{2+}\)-signaling and cell survival following cisplatin (100µM) treatment. Transcript levels were quantified with RT-PCR, protein abundance with Western blotting, cytosolic \(Ca^{2+}\)-activity ([\(Ca^{2+}\)]i) with Fura-2-fluorescence, SOCE from increase of [\(Ca^{2+}\)]i following \(Ca^{2+}\)-readdition after Ca2+-store depletion, and apoptosis utilizing flow cytometry. Transcript levels of Orai1 and STIM1, protein expression of Orai1, STIM1, and phosphorylated Akt, as well as SOCE were significantly higher in A2780cis than A2780 cells. SOCE was decreased by Akt inhibitor III (SH-6, 10µM) in A2780cis but not A2780 cells and decreased in both cell lines by Orai1 inhibitor 2-aminoethoxydiphenyl borate (2-ABP, 50µM). Phosphatidylserine exposure and late apoptosis following cisplatin treatment were significantly lower in A2780cis than A2780 cells, a difference virtually abolished by SH-6 or 2-ABP. In conclusion, Orai1/STIM1 expression and function are increased in therapy resistant ovary carcinoma cells, a property at least in part due to enhanced Akt activity and contributing to therapy resistance in those cells.
Limiting dietary carbohydrates inhibits glioma growth in preclinical models. Therefore, the ERGO trial (NCT00575146) examined feasibility of a ketogenic diet in 20 patients with recurrent glioblastoma. Patients were put on a low-carbohydrate, ketogenic diet containing plant oils. Feasibility was the primary endpoint, secondary endpoints included the percentage of patients reaching urinary ketosis, progression-free survival (PFS) and overall survival. The effects of a ketogenic diet alone or in combination with bevacizumab was also explored in an orthotopic U87MG glioblastoma model in nude mice. Three patients (15%) discontinued the diet for poor tolerability. No serious adverse events attributed to the diet were observed. Urine ketosis was achieved at least once in 12 of 13 (92%) evaluable patients. One patient achieved a minor response and two patients had stable disease after 6 weeks. Median PFS of all patients was 5 (range, 3-13) weeks, median survival from enrollment was 32 weeks. The trial allowed to continue the diet beyond progression. Six of 7 (86%) patients treated with bevacizumab and diet experienced an objective response, and median PFS on bevacizumab was 20.1 (range, 12-124) weeks, for a PFS at 6 months of 43%. In the mouse glioma model, ketogenic diet alone had no effect on median survival, but increased that of bevacizumab-treated mice from 52 to 58 days (p<0.05). In conclusion, a ketogenic diet is feasible and safe but probably has no significant clinical activity when used as single agent in recurrent glioma. Further clinical trials are necessary to clarify whether calorie restriction or the combination with other therapeutic modalities, such as radiotherapy or anti-angiogenic treatments, could enhance the efficacy of the ketogenic diet.
Abstract
Background
HLA-G is a non-classical MHC class I molecule which exerts strong immunosuppressive effects on various immune cells. Several membrane-bound and soluble isoforms are known. Physiologically, HLA-G is predominantly expressed in the placenta, where it contributes to protecting the semi-allogeneic embryo from rejection by the maternal immune system. However, HLA-G is also often upregulated during tumourigenesis, such as in ovarian cancer. The aim of this thesis is to investigate how soluble HLA-G may contribute to local immunosuppression in ovarian carcinomas, and to characterize HLA-G expression in different ovarian carcinoma subtypes and metastases.
Results
As reported by others, physiological HLA-G expression is restricted to few tissues, such as placenta and testes. Here, HLA-G was also detected in the medulla of the adrenal gland. In contrast, HLA-G expression was frequently detected in tumours of all assessed subtypes of ovarian carcinomas (serous, mucinous, endometrioid and clear cell). Highest expression levels were detected in high-grade serous carcinomas. In primary tumours, expression of HLA-G correlated with expression of classical MHC class I molecules HLA-A, -B and -C. Surprisingly, high levels of HLA-G were also detected on dendritic cells in local lymph nodes. As no expression of HLA-G was inducible in monocytes or dendritic cells from healthy donors in response to IL-10 or IL-4, we speculated that tumour-derived soluble HLA-G might be transferred to dendritic cells via the lymphatic system. Accordingly, high levels of tumour-derived soluble HLA-G were detected in ovarian cancer ascites samples. In vitro, dendritic cells expanded in the presence of IL-4, IL-10 and GM-CSF (DC-10) were particularly prone to binding high amounts of soluble HLA-G via ILT receptors. Furthermore, HLA-G loaded DC-10 cells inhibited the proliferation of CD8 effector cells and induced regulatory T cells, even when the DC-10 cells had been fixed with paraformaldehyde.
Conclusion
The immunosuppressive molecule HLA-G is overexpressed in high-grade serous ovarian carcinomas, which account for the majority of ovarian cancers. In particular tumours with a high mutational burden and intact expression of classical, immunogenic MHC class Ia molecules may use HLA-G to escape from immunosurveillance. Additionally, tumour-derived soluble HLA-G may inhibit adaptive immune responses by binding to dendritic cells in local lymph nodes. Dendritic cells usually play a decisive role in the initiation of adaptive anti-tumour immune responses by presenting tumour antigens to cytotoxic T cells. In contrast, dendritic cells loaded with soluble HLA-G inhibit the proliferation of effector T cells and promote the induction of regulatory T cells. Thus, soluble HLA-G that is transferred to dendritic cells via lymphatic vessels may enable ovarian carcinomas to remotely suppress anti-tumour immune responses in local lymph nodes. This novel immune-escape mechanism may also exist in other solid tumours that express HLA-G.
Cancer stem cell (CSC) biology and tumor immunology have shaped our understanding of tumorigenesis. However, we still do not fully understand why tumors can be contained but not eliminated by the immune system and whether rare CSCs are required for tumor propagation. Long latency or recurrence periods have been described for most tumors. Conceptually, this requires a subset of malignant cells which is capable of initiating tumors, but is neither eliminated by immune cells nor able to grow straight into overt tumors. These criteria would be fulfilled by CSCs. Stem cells are pluripotent, immune-privileged, and long-living, but depend on specialized niches. Thus, latent tumors may be maintained by a niche-constrained reservoir of long-living CSCs that are exempt from immunosurveillance while niche-independent and more immunogenic daughter cells are constantly eliminated. The small subpopulation of CSCs is often held responsible for tumor initiation, metastasis, and recurrence. Experimentally, this hypothesis was supported by the observation that only this subset can propagate tumors in non-obese diabetic/scid mice, which lack T and B cells. Yet, the concept was challenged when an unexpectedly large proportion of melanoma cells were found to be capable of seeding complex tumors in mice which further lack NK cells. Moreover, the link between stem cell-like properties and tumorigenicity was not sustained in these highly immunodeficient animals. In humans, however, tumor-propagating cells must also escape from immune-mediated destruction. The ability to persist and to initiate neoplastic growth in the presence of immunosurveillance - which would be lost in a maximally immunodeficient animal model - could hence be a decisive criterion for CSCs. Consequently, integrating scientific insight from stem cell biology and tumor immunology to build a new concept of "CSC immunology" may help to reconcile the outlined contradictions and to improve our understanding of tumorigenesis.
Background
Overexpression of transketolase-like 1 protein TKTL1 in cancer cells has been reported to correlate with enhanced glycolysis and lactic acid production. Furthermore, enhanced TKTL1 expression was put into context with resistance to chemotherapy and ionizing radiation. Here, a panel of human malign and benign cells, which cover a broad range of chemotherapy and radiation resistance as well as reliance on glucose metabolism, was analyzed in vitro for TKTL1 expression.
Methods
17 malign and three benign cell lines were characterized according to their expression of TKTL1 on the protein level with three commercially available anti-TKTL1 antibodies utilizing immunohistochemistry and Western blot, as well as on mRNA level with three published primer pairs for RT-qPCR. Furthermore, sensitivities to paclitaxel, cisplatin and ionizing radiation were assessed in cell survival assays. Glucose consumption and lactate production were quantified as surrogates for the “Warburg effect”.
Results
Considerable amounts of tktl1 mRNA and TKTL1 protein were detected only upon stable transfection of the human embryonic kidney cell line HEK293 with an expression plasmid for human TKTL1. Beyond that, weak expression of endogenous tktl1 mRNA was measured in the cell lines JAR and U251. Western blot analysis of JAR and U251 cells did not detect TKTL1 at the expected size of 65 kDa with all three antibodies specific for TKTL1 protein and immunohistochemical staining was observed with antibody JFC12T10 only. All other cell lines tested here revealed expression of tktl1 mRNA below detection limits and were negative for TKTL1 protein. However, in all cell lines including TKTL1-negative HEK293-control cells, antibody JFC12T10 detected multiple proteins with different molecular weights. Importantly, JAR and U251 did neither demonstrate an outstanding production of lactic acid nor increased resistance against chemotherapeutics or to ionizing radiation, respectively.
Conclusion
Using RT-qPCR and three different antibodies we observed only exceptional occurrence of TKTL1 in a panel of malignant human cell lines in vitro. The presence of TKTL1 was unrelated to either the rate of glucose consumption/lactic acid production or resistance against chemo- and radiotherapy.
Glioblastomas are characterized by an aggressive local growth pattern, a marked degree of invasiveness and poor prognosis. Tumor invasiveness is facilitated by the increased activity of proteolytic enzymes which are involved in destruction of the extracellular matrix of the surrounding healthy brain tissue. Elevated levels of matrix metalloproteinases (MMPs) were found in glioblastoma (GBM) cell-lines, as well as in GBM biopsies as compared with low-grade astrocytoma (LGA) and normal brain samples, indicating a role in malignant progression. A careful review of the available literature revealed that both the expression and role of several of the 23 human MMP proteins is controversely discussed and for some there are no data available at all. We therefore screened a panel of 15 LGA and 15 GBM biopsy samples for those MMPs for which there is either no, very limited or even contradictory data available. Hence, this is the first complete compilation of the expression pattern of all 23 human MMPs in astrocytic tumors. This study will support a better understanding of the specific expression patterns and interaction of proteolytic enzymes in malignant human glioma and may provide additional starting points for targeted patient therapy.
The ectonucleotidases CD39 and CD73 degrade ATP to adenosine which inhibits immune responses via the \(A_{2A}\) adenosine receptor (ADORA2A) on T and NK cells. The current study investigates the potential therapeutic use of the specific anti CD39- and anti CD73-antibodies A1 (CD39) and 7G2 (CD73) as these two ectonucleotidases are overexpressed in ovarian cancer (OvCA). As expected, NK cell cytotoxicity against the human ovarian cancer cell lines OAW-42 or SK-OV-3 was significantly increased in the presence of A1 or 7G2 antibody. While this might partly be due to antibody-dependent cell-mediated cytotoxicity, a luciferase-dependent assay for quantifying biologically active adenosine further showed that A1 and 7G2 can inhibit CD39 and CD73-dependent adenosine-generation. In turn, the reduction in adenosine levels achieved by addition of A1 and 7G2 to OAW-42 or SK-OV-3 cells was found to de-inhibit the proliferation of \(CD4^+\) T cells in coculture with OvCA cells. Likewise, blocking of CD39 and CD73 on OvCA cells via A1 and 7G2 led to an increased cytotoxicity of alloreactive primed T cells. Thus, antibodies like A1 and 7G2 could improve targeted therapy in ovarian cancer not only by specifically labeling overexpressed antigens but also by blocking adenosine-dependent immune evasion in this immunogenic malignancy.
The antibody trastuzumab (Herceptin) has substantially improved overall survival for patients with aggressive HER2-positive breast cancer. However, about 70% of all treated patients will experience relapse or disease progression. This may be related to an insufficient targeting of the CD44(high)CD24(low) breast cancer stem cell subset, which is not only highly resistant to chemotherapy and radiotherapy but also a poor target for trastuzumab due to low HER2 surface expression. Hence, we explored whether the new antibody-drug conjugate T-DM1, which consists of the potent chemotherapeutic DM1 coupled to trastuzumab, could improve the targeting of these tumor-initiating or metastasis-initiating cells. To this aim, primary HER2-overexpressing tumor cells as well as HER2-positive and HER2-negative breast cancer cell lines were treated with T-DM1, and effects on survival, colony formation, gene and protein expression as well as antibody internalization were assessed. This revealed that CD44(high)CD24(low)HER2(low) stem cell-like breast cancer cells show high endocytic activity and are thus particularly sensitive towards the antibody-drug conjugate T-DM1. Consequently, preexisting CD44(high)CD24(low) cancer stem cells were depleted by concentrations of T-DM1 that did not affect the bulk of the tumor cells. Likewise, colony formation was efficiently suppressed. Moreover, when tumor cells were cocultured with natural killer cells, antibody-dependent cell-mediated cytotoxicity was enhanced, and EMT-mediated induction of stem cell-like properties was prevented in differentiated tumor cells. Thus our study reveals an unanticipated targeting of stem cell-like breast cancer cells by T-DM1 that may contribute to the clinical efficacy of this recently approved antibody-drug conjugate.
Das humane Genom besteht zu ungefähr 8 % aus humanen endogenen Retroviren (HERVs),
jedoch sind viele aufgrund von Mutationen oder Deletionen nicht mehr funktionell. Trotzdem
wurden funktionelle HERV-Proteine gefunden, welche offene Leserahmen (ORFs) besitzen
und für funktionelle Hüll-Glykoproteine wie z.B. Syncytin-1, Syncytin-2 und HML-2
kodieren. Diese HERV-Hüllproteine beinhalten eine suppressive Domäne (SU) und
induzieren möglicherweise eine Immunsuppression diverser Immunzellen während einer
gesunden Schwangerschaft.
In dieser Arbeit wurden spezifisch die modulatorischen Eigenschaften verschiedener HERVHüllproteine
(Syncytin-1, -2 und HML-2) auf Immunzellen untersucht.
Wir konnten zeigen, dass die HERV-Bindungsrezeptoren ASCT-1, -2 und MFSD2A auf der
Oberfläche von T-Zellen und DCs exprimiert werden. Für funktionelle Experimente wurden
HERV-Hüllproteine transgen in CHO-Zellen exprimiert, die als Effektorzellen in Ko-Kultur-
Systemen verwendet wurden. Es konnte keine Hemmung der PMA/Ionomycin-stimulierten
T-Zell-Proliferation durch die Effektorzellen gefunden werden. Darüber hinaus
beeinträchtigten die Effektorzellen nicht die Expression von Reifungsmarkern auf DCs nach
LPS-Aktivierung, induzierten jedoch die Produktion der pro-inflammatorischen Zytokine IL-
12 und TNF-α. Dagegen inhibierten die konstitutiv HERV-Hüllprotein-exprimierenden
Chorionkarzinom-Zelllinien BeWo und JEG die PMA/Ionomycin-stimulierte T-Zell-
Proliferation sehr effektiv. Die Chorionkarzinom-Zelllinien hatten ebenfalls keinen Einfluss
auf die phänotypische LPS-DC-Reifung, modulierten aber die LPS-DC-Zytokin-Antwort sehr
effektiv zu einem suppressiven Profil durch eine Inhibition der pro-inflammatorischen
Zytokine IL-12 und TNF-α sowie einen Anstieg von anti-inflammatorischem IL-10. BeWound
JEG-Zellen, aber auch HERV-Hüllprotein-exprimierende Effektorzellen verändern die
durch LPS-DC-stimulierte allogene T-Zell-Proliferation. Dies war mit einer verringerten
Bildung von DC/T-Zell-Konjugaten sowie mit einer Hemmung der IFN-γ-Sekretion und der
Ca2+-Mobilisation dieser T-Zellen assoziiert. Des Weiteren wurden eine reduzierte p-Tyrosin-
Akkumulation und kein Ausschluss des F-Aktin-Signals in der immunologischen Synapse,
der Kontaktstelle dieser DC/T-Zell-Konjugate, gefunden.
Zusammenfassend lassen diese Ergebnisse vermuten, dass HERV-Hüllproteine die T-Zell-
Proliferation nicht direkt beeinflussen, sich aber modulierend auf DCs auswirken und dadurch
mit deren allogene T-Zell-Proliferation interferieren.
Background: miRNA profiles are promising biomarker candidates for a manifold of human pathologies, opening new avenues for diagnosis and prognosis. Beyond studies that describe miRNAs frequently as markers for specific traits, we asked whether a general pattern for miRNAs across many diseases exists.
Methods: We evaluated genome-wide circulating profiles of 1,049 patients suffering from 19 different cancer and non-cancer diseases as well as unaffected controls. The results were validated on 319 individuals using qRT-PCR.
Results: We discovered 34 miRNAs with strong disease association. Among those, we found substantially decreased levels of hsa-miR-144* and hsa-miR-20b with AUC of 0.751 ( 95% CI: 0.703-0.799), respectively. We also discovered a set of miRNAs, including hsa-miR-155*, as rather stable markers, offering reasonable control miRNAs for future studies. The strong downregulation of hsa-miR-144* and the less variable pattern of hsa-miR-155* has been validated in a cohort of 319 samples in three different centers. Here, breast cancer as an additional disease phenotype not included in the screening phase has been included as the 20th trait.
Conclusions: Our study on 1,368 patients including 1,049 genome-wide miRNA profiles and 319 qRT-PCR validations further underscores the high potential of specific blood-borne miRNA patterns as molecular biomarkers. Importantly, we highlight 34 miRNAs that are generally dysregulated in human pathologies. Although these markers are not specific to certain diseases they may add to the diagnosis in combination with other markers, building a specific signature. Besides these dysregulated miRNAs, we propose a set of constant miRNAs that may be used as control markers.
In the present study, we assessed, if the novel dual phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitor NVP-BEZ235 radiosensitizes triple negative (TN) MDA-MB-231 and estrogen receptor (ER) positive MCF-7 cells to ionizing radiation under various oxygen conditions, simulating different microenvironments as occurring in the majority of breast cancers (BCs). Irradiation (IR) of BC cells cultivated in hypoxic conditions revealed increased radioresistance compared to normoxic controls. Treatment with NVP-BEZ235 completely circumvented this hypoxia-induced effects and radiosensitized normoxic, reoxygenated, and hypoxic cells to similar extents. Furthermore, NVP-BEZ235 treatment suppressed HIF-1α expression and PI3K/mTOR signaling, induced autophagy, and caused protracted DNA damage repair in both cell lines in all tested oxygen conditions. Moreover, after incubation with NVP-BEZ235, MCF-7 cells revealed depletion of phospho-AKT and considerable signs of apoptosis, which were signifi-cantly enhanced by radiation. Our findings clearly demonstrate that NVP-BEZ235 has a clinical relevant potential as a radiosensitizer in BC treatment.
Ergebnisse der gynäkolgischen Descensuschirurgie unter Verwendung des GYNECARE PROLIFT® prolenemesh am Krankenhaus Agatharied
Der Descensus genitalis ist eine der häufigsten gutartigen Erkrankungen der Frau, im Jahr 2010 waren mehr als 316 Millionen Frauen weltweit betroffen. Es besteht ein Lebensrisiko von 11,1% für eine chirurgische Intervention für eine 80jährige Frau.
Die Gründe liegen v. a. in der Anzahl vaginaler (operativer) Geburten, Adiopsitas, Z.n. Hysterektomie, Überalterung und chronisch erhöhter intraabdominaler Druck.
Die klinische Symptomatik besteht aus den typischen Senkungssymptomen wie Fremdkörper- und Druckgefühl, Ulcerationen mit Blutung, Fluor, Infektionen und Schmerzen. Außerdem kann es zu anorectaler Dysfunktion und Störungen der Blasenspeicher- und entleerungsfunktion kommen. Auch werden häufig Störungen der Sexualfunktion beschrieben.
Die anatomiegerechte Beckenbodendefektbehebung mittels Polypropylene-Kunststoffnetzen (GYNECARE PROLIFT® prolenemesh) über den vaginalen Zugang wird zunehmend, neben den klassischen Descensusoperationen, zur Rekonstruktion des weiblichen Beckenbodens verwendet.
Anhand der prä- und postoperativen Anamnese und Untersuchung nach dem POP-Q Schema einschließlich intra- und postoperativer Veräufe sowie 4 etablierter Fragebögen (PFDI-20, PFIQ-7, PISQ-12 und PGI-C) zu subjektiven Einschränkungen durch den Descensus erfolgt die Evaluation des Erfolges der Netzimplantation und ein Vergleich mit Ergebnissen anderer Methoden der Descensuschirurgie.
Ergebnisse: Netzspezifische Komplikationen wie Exposition in die Scheide, Erosion in Nachbarorgane, Schrumpfung der Netze mit Schmerzen, Auftreten einer De Novo Belastungsinkontinenz oder einer Dyspareunie wurden im vorliegenden Kollektiv deutlich seltener als in der Literatur verzeichnet. Die Netzimplantation war in 81,5% (Stadium 0 oder 1) erfolgreich, es kam in 18,5% zu einem Rezidiv. Je nach Literatur und betroffenem Kompartiment liegen die Rezidivraten nach Mesheinlage zwischen 3,5 und 46% und bei 2 bis 42,5% nach klassischen Descensusoperationen. In allen 4 Fragebögen wurde eine Verbesserung der Lebensqualität, der sexuellen Zufriedenheit und der Speicher- und Entleerungsfunktion von Blase und Darm verzeichnet, jedoch war die Netzimplantation gleichwertig mit den klassischen Senkungsoperationen.
Clinical prognosis of metastasized colorectal carcinoma (CRC) is still not at desired levels and novel drugs are needed. Here, we focused on the multi-tyrosine kinase inhibitor E7080 (Lenvatinib) and assessed its therapeutic efficacy against human CRC cell lines in vitro and human CRC xenografts in vivo. The effect of E7080 on cell viability was examined on 10 humanCRCcell lines and humanendothelial cells (HUVEC). The inhibitory effect of E7080 on VEGF-induced angiogenesis was studied in an ex vivo mouse aortic ring angiogenesis assay. In addition, the efficacy of E7080 against xenografts derived fromCRC cell lines and CRC patient resection specimenswithmutated KRASwas investigated in vivo. Arelatively low cytotoxic effect of E7080 on CRC cell viabilitywas observed in vitro. Endothelial cells (HUVEC)weremore susceptible to the incubation with E7080. This is in line with the observation that E7080 demonstrated an anti-angiogenic effect in a three-dimensional ex vivo mouse aortic ring angiogenesis assay. E7080 effectively disrupted CRC cell-mediated VEGF-stimulated growth of HUVEC in vitro. Daily in vivo treatment with E7080 (5 mg/kg) significantly delayed the growth of KRAS mutated CRC xenografts with decreased density of tumor-associated vessel formations and without tumor regression. This observation is in line with results that E7080 did not significantly reduce the number of Ki67-positive cells in CRC xenografts. The results suggest antiangiogenic activity of E7080 at a dosage thatwas well tolerated by nudemice. E7080 may provide therapeutic benefits in the treatment of CRC with mutated KRAS.
Background
The human endogenous retrovirus K (HERV-K) has been acquired by the genome of human ancestors million years ago. It is the most complete of the HERVs with transcriptionally active gag, pol and env genes. Splice variants of env, which are rec, 1.5 kb transcript and Np9 have been suggested to be tumorigenic. Transcripts of HERV-K have been detected in a multitude of human cancers. However, no such reports are available concerning glioblastomas (GBM), the most common malignant brain tumor in adults. Patients have a limited prognosis of 14.6 months in median, despite standard treatment. Therefore, we elucidated whether HERV-K transcripts could be detected in these tumors and serve as new molecular target for treatment.
Findings
We analyzed human GBM cell lines, tissue samples from patients and primary cell cultures of different passages for HERV-K full length mRNA and env, rec and 1.5 kb transcripts. While the GBM cell lines U138, U251, U343 and GaMG displayed weak and U87 strong expression of the full length HERV-K, the splice products could not be detected, despite a weak expression of env mRNA in U87 cells. Very few tissue samples from patients showed weak expression of env mRNA, but none of the rec or 1.5 kb transcripts. Primary cells expressed the 1.5 kb transcript weakly in early passages, but lost HERV-K expression with extended culture time.
Conclusions
These data suggest that HERV-K splice products do not play a role in human malignant gliomas and therefore, are not suitable as targets for new therapy regimen.
Störungen des PI3K-AKT-Signalweges treten besonders häufig in Endometrium und Ovarialkarzinomen auf. Ursache kann eine Überaktivierung von Wachstumsfaktor-Rezeptoren, Mutationen oder der Funktionsverlust von PTEN sein, was zu
einer Störung der Regulation und damit zu einer Überaktivierung des PI3K-AKTSignalweges führt und so das Einleiten autophagischer Prozesse verhindert. Hierauf
kommt es zu unkontrollierter Zellvermehrung, welche zur Tumorentstehung und Tumorprogression beiträgt [12][23].
Die in dieser Arbeit durchgeführten Untersuchungen konnten zeigen, dass die Hemmung des PI3K-AKT-Signalweges durch den PI3K-Inhibitor AEZS-126 erfolgversprechende
antiproliferative Effekte in in vitro-Modellen des Ovarialkarzinoms zeigte. In vitro konnte die niedermolekulare Pyridopyrazin-Verbindung AEZS-126
das Wachstum und die Progression von Zellen der parentalen Ovarialkarzinom-Zelllinie A2780, der daraus abgeleiteten cis-Platin-resistenten Tochterzelllinie Acis2780 und der aus einem Ovar-Adenokarzinom gewonnenen Zelllinie SKOV-3 signifikant hemmen. In Vitalitätsassays ermittelte IC50-Werte lagen im mikromolaren Bereich
und zeigten konzentrationsabhängige Antitumor-Effekte. Neben den AEZS-126-abhängigen Effekten wurde auch die Wirksamkeit des mTOR-Inhibitors Rapamycin
auf die Zelllinien A2780 und Acis2780 untersucht. Es zeigten sich ebenfalls konzentrationsabhängige
antiproliferative Effekte. Durch die Kombination der beiden Inhibitoren AEZS-126 und Rapamycin konnte zusätzlich eine gesteigerte Wirksamkeit gegen die Tumorzellen erzielt werden und synergistische Effekte traten auf. ImWestern-Blot konnte nach Inkubation der Ovarialkarzinomzelllinien mit AEZS-126 durch den Einsatz von AEZS-126 eine verminderte Expression von pAKT nachgewiesen werden, welche insbesondere bei den cis-Platin-resistenten Acis2780-Zellen durch die Kombination mit Rapamycin noch verstärkt wurde.
Durch FACS-Analysen konnte gezeigt werden, dass die Ovarialkarzinomzellen durch die Behandlung mit AEZS-126 im Wachstum gehemmt werden und unabhängig von ihrer Zellzyklusphase in den Zelltod geführt werden können. So zeigte sich in den Zellzyklusanalysen eine konzentrationsabhängige Verschiebung der Zellzahl
von der G0/G1-Phase in die sub-G0-Phase, welche die Population der toten Zellen darstellt.
Eine Spezifizierung des Zelltod-Mechanismuses erfolgte einerseits durch Annexin-V-FITC-FACS-Analysen und andererseits durch Vitalitätsassays mit Koinkubation
von AEZS-126 mit dem Caspase-Inhibitor zVAD-fmk, dem Nekroptose-Inhibitor Necrostatin-1 und dem Nekrose-Inhibitor Necrox-2. Aus diesen Untersuchungen ging
klar hervor, dass AEZS-126 in den Zelllinien A2780, Acis2780 und SKOV-3 Nekroptose induziert. Rapamycin alleine zeigte sowohl apoptotische als auch nekrotische
Wirkmechanismen. Die Kombination der beiden Inhibitoren AEZS-126 und Rapamycin führte zu einer synergistischen Wirkverstärkung, was sich in einem verstärkten
Absterben der Zellen schon bei geringeren eingesetzten Konzentrationen der beiden Inhibitoren zeigte. Auch hier traten hauptsächlich nekrotische Effekte auf.
Von besonderem Interesse war die Interaktion von Ovarialkarzinomzellen (A2780, Acis2780), die mit AEZS-126 vorbehandelt worden waren, mit Zellen des Immunsystems.
So konnte gezeigt werden, dass AEZS-126 eine verbesserte Zelllyse der Tumorzellen durch NK-Zellen ermöglicht. Zusätzlich konnten die cis-Platin-resistenten
Acis2780-Zellen durch Vorbehandlung mit entsprechende Konzentrationen des PI3KInhibitors in vergleichbarem Ausmaß wie die parentalen A2780-Zellen für die Lyse
durch NK-Zellen zugänglich gemacht werden.
AEZS-126 scheint auf Grund dieser Ergebnisse und der schon nachgewiesenen guten antiproliferativen Wirkung von AEZS-126 auf verschiedene Zelllinien ein geeigneter
Kandidat für weiterführende in vivo-Versuche zu sein.
Zusätzlich sollte erwogen werden, neben der Inhibiton des PI3K-AKT-Signalweges eine zeitgleiche Hemmung des Ras-Raf-MEK-ERK-Signalweges in Betracht zu ziehen.
Durch die Interaktionen der beiden Signalwege könnte es sonst bei der Inaktivierung des einen zur Aktivierung des anderen Signalweges kommen [143]. Durch eine Überexpression von pAKT durch eine PTEN-Mutation kommt es beispielsweise zur Inaktivierung von Ras und der darauf folgenden Signalkaskade, während ein erhöhtes
Expressionsniveau an pAKT im PI3K-AKT-Signalweg zu einer Aktivierung von mTOR und damit zur Hemmung autophagischer Prozesse führt [23]. So kann die Phosphorylierung des Proteins p70S6K, dem Schlüsselmolekül zwischen den beiden
Signalwegen, welches mTOR nachgeschaltet ist, durch Rapamycin gehemmt werden und damit zu einer erhöhten Aktivierung von AKT und ERK führen [143]. Durch
die Kombinationsbehandlung mit Inhibitoren des PI3K-AKT-Signalweges, die an verschiedenen Stellen der Signalkaskade angreifen, kann, wie in dieser Arbeit gezeigt wurde, die Antitumorwirkung verstärkt werden. Die in dieser Arbeit untersuchten Inhibitoren AEZS-126 und Rapamycin zeigten bei den parentalen Ovarialkarzinom-
zellen A2780 und den cis-Platin-resistenten Acis2780-Zellen in der Kombinationsbehandlung
synergistische Effekte und führten schon bei geringen Konzentrationen zu verstärkter antiproliferativer Wirksamkeit.
Aus den erzielten Ergebnissen geht hervor, dass die Kombinationsbehandlung mit AEZS-126 und Rapamycin geeignet wäre, in in vivo-Experimenten weiter untersucht
zu werden.