Clostridium Perfringens Enterotoxin (CPE) and CPE-Binding Domain (c-CPE) for the Detection and Treatment of Gynecologic Cancers

Clostridium perfringens enterotoxin (CPE) is a three-domain polypeptide, which binds to Claudin-3 and Claudin-4 with high affinity. Because these receptors are highly differentially expressed in many human tumors, claudin-3 and claudin-4 may provide an efficient molecular tool to specifically identify and target biologically aggressive human cancer cells for CPE-specific binding and cytolysis. In this review we will discuss these surface proteins as targets for the detection and treatment of chemotherapy-resistant gynecologic malignancies overexpressing claudin-3 and -4 using CPE-based theranostic agents. We will also discuss the use of fluorescent c-CPE peptide in the operative setting for real time detection of micro-metastatic tumors during surgery and review the potential role of CPE in other medical applications

Neratinib shows efficacy in the treatment of HER2/neu amplified uterine serous carcinoma in vitro and in vivo

Uterine serous carcinoma (USC) represents an aggressive variant of endometrial cancer and accounts for a large proportion of deaths annually. HER2/neu amplification is associated with USC in approximately 30–35% of cases. The objective of this study was to determine the sensitivity of a panel of primary USC cell lines to the small tyrosine kinase inhibitor neratinib, an ErbB1 and HER2 inhibitor, both in vitro and in vivo. HER2/neu amplification was determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in 24 USC cell lines. Flow cytometry was used to determine the effects of neratinib on cell viability, cell cycle distribution and signaling in vitro. Mice harboring HER2/neu amplified xenografts were treated with neratinib to assess the efficacy of the drug in vivo. HER2/neu amplification was noted in 8/24 primary cell lines. Data regarding the efficacy of neratinib was determined using 4 HER2 amplified cell lines and 4 non-amplified cell lines with similar growth rates. Data revealed that cell lines with HER2/neu amplification were exquisitely more sensitive to neratinib compared to non-amplified cell lines (mean±SEM IC50: 0.011μM±0.0008 vs. 0.312μM±0.0456 p<0.0001). Neratinib caused arrest in the G0/G1 phase of the cell cycle and resulted in decreased autophosphorylation of HER2 and activation of S6. Neratinib treated mice harboring xenografts of HER2/neu amplified USC showed delayed tumor growth and improved overall survival compared to vehicle (p=0.0019). Neratinib may be a potential treatment option for patients harboring HER2/neu amplified USC. Clinical trials for this subset of endometrial cancer patients are warranted. •Neratinib, an irreversible small tyrosine kinase inhibitor, inhibits HER2/neu amplified USC proliferation, cell cycle progression and signaling in vitro.•Neratinib inhibits HER2/neu amplified USC xenograft growth and improves overall survival in vivo.•Clinical trials in carefully selected patients are warranted

Abstract 135: Mutational landscape of uterine and ovarian carcinosarcomas reveals new recurrently-mutated histone core genes as drivers of epithelial-mesenchymal transition

Abstract Objective: Carcinosarcomas (CS) of the uterus and ovary are highly aggressive neoplasms containing both carcinomatous and sarcomatous elements. While an increasing body of evidence supports the origin of both CS elements from a common epithelial cell that undergoes sarcomatous dedifferentiation, limited information is currently available about the role of somatic mutations (SNV) and copy number variations (CNV) in these rare tumors. Accordingly, the objective of our study was to evaluate the genetic landscape of uterine and ovarian CSs by whole-exome-sequencing (WES). Methods: We analyzed the mutational landscape of 63 fresh frozen CS biopsies and 5 primary CS cell lines by WES, most of which were matched to normal DNA from the same patients. We also performed multi region WES in separate carcinoma and sarcoma areas to resolve the genetic architecture and evolutionary histories of CS. Finally, in transfection experiments we validated somatic histone 2A and 2B mutations as potential drivers of epithelial-mesenchymal transition (EMT). Results: Our results demonstrated the presence of two major genetic types of uterine CSs [i.e., uterine serous carcinoma-like (USC) profile and endometrioid carcinoma-like profile (EAC)] and provided evidence that both subtypes, as well as ovarian CS, arise from sarcomatous transformation of carcinomas. In addition to recurrent mutations in cancer genes previously identified in USC and EAC such as TP53, PIK3CA, PPP2R1A, KRAS, PTEN, CHD4/Mi2b and BCOR, we found an excess of mutations in histones H2A and H2B, as well as significant amplification of the segment of chromosome 6p harboring the histone cluster containing these genes. We also found frequent deletions comprising TP53 and MBD3, (a member with CHD4/Mi2b of the NuRD-chromatin-modification-complex), and frequent amplification of chromosome segments containing PIK3CA, CCNE1, TERT and c-MYC. Amplifications of the histone cluster and TERT were significantly more frequent in CS than their epithelial counterparts. Stable transgenic expression H2A and H2B in USC cell lines demonstrated that mutant, but not wild type H2A and H2B increased expression of markers of epithelial-mesenchymal transition (EMT), suggesting a role in sarcomatous transformation. Comparison of the phylogenetic relationships of carcinomatous and sarcomatous elements of the same tumors demonstrated separate lineages resulting in these two components. Conclusions: Our results provide new insight into the origins and development of uterine and ovarian CS and defined the genetic landscape of this type of malignant tumor. These findings also suggest new therapeutic targets for these highly aggressive neoplasms. Citation Format: Gulden Menderes, Siming Zhao, Carlton L. Schwab, Salvatore Lopez, Jonathan D. Black, Emiliano Cocco, Stefania Bellone, Dan-Arin Silasi, Elena Ratner, Masoud Azodi, Babak Litkouhi, Peter E. Schwartz, Joseph Schlossinger, Richard Lifton, Alessandro Santin. Mutational landscape of uterine and ovarian carcinosarcomas reveals new recurrently-mutated histone core genes as drivers of epithelial-mesenchymal transition. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 135

T‐DM1, a novel antibody–drug conjugate, is highly effective against primary HER2 overexpressing uterine serous carcinoma in vitro and in vivo

Amplification of c-erbB2 has been reported in over 30% of uterine serous carcinoma (USC) and found to confer poor survival because of high proliferation and increased resistance to therapy. In this study, we evaluated for the first time Trastuzumab emtansine (T-DM1), a novel antibody–drug conjugate, against multiple epidermal growth factor receptor-2 (HER2)-positive USC cells in vitro followed by developing a supportive in vivo model. Fifteen primary USC cell lines were assessed by immunohistochemistry (IHC) and flow cytometry for HER2 protein expression. C-erbB2 gene amplification was evaluated using fluorescent in situ hybridization. Sensitivity to T-DM1 and trastuzumab (T)-induced antibody-dependent cell-mediated cytotoxicity was evaluated in 5-h chromium release assays. T-DM1 and T cytostatic and apoptotic activities were evaluated using flow-cytometry-based proliferation assays. In vivo activity of T-DM1 versus T in USC xenografts in SCID mice was also evaluated. High levels of HER2 protein overexpression and HER2 gene amplification were detected in 33% of USC cell lines. T-DM1 was considerably more effective than trastuzumab in inhibiting cell proliferation and in causing apoptosis (P = 0.004) of USC showing HER2 overexpression. Importantly, T-DM1 was highly active at reducing tumor formation in vivo in USC xenografts overexpressing HER2 (P = 0.04) and mice treated with TDM-1 had significantly longer survival when compared to T-treated mice and control mice (P ≤ 0.0001). T-DM1 shows promising antitumor effect in HER2-positive USC cell lines and USC xenografts and its activity is significantly higher when compared to T. T-DM1 may represent a novel treatment option for HER2-positive USC patients with disease refractory to trastuzumab and traditional chemotherapy

Solitomab, an Epithelial Cell Adhesion Molecule/CD3 Bispecific Antibody (BiTE), Is Highly Active Against Primary Chemotherapy-Resistant Ovarian Cancer Cell Lines In Vitro and Fresh Tumor Cells Ex Vivo

BACKGROUND: Solitomab is a novel, bispecific, single-chain antibody that targets epithelial cell adhesion molecule (EpCAM) on tumor cells and also contains a cluster of differentiation 3 (CD3) (T-cell coreceptor) binding region. The authors evaluated the in vitro activity of solitomab against primary chemotherapy-resistant epithelial ovarian carcinoma cell lines as well as malignant cells in ascites. METHODS: EpCAM expression was evaluated by flow cytometry in 5 primary ovarian cancer cell lines and in 42 fresh ovarian tumor cell cultures in ascites from patients with mainly advanced or recurrent, chemotherapy-resistant disease. The potential activity of solitomab against EpCAM-positive tumor cells was evaluated by flow cytometry, proliferation, and 4-hour chromium-release, cell-mediated cytotoxicity assays. RESULTS: EpCAM expression was detected by flow cytometry in approximately 80% of the fresh ovarian tumors and primary ovarian tumor cell lines tested. EpCAM-positive, chemotherapy-resistant cell lines were identified as resistant to natural killer cell-mediated or T-cell-mediated killing after exposure to peripheral blood lymphocytes in 4-hour chromium-release assays (mean +/- standard error of the mean, 3.6% 60.7% of cells killed after incubation of EpCAM-positive cell lines with control bispecific antibody). In contrast, after incubation with solitomab, EpCAM-positive, chemotherapy-resistant cells became highly sensitive to T-cell cytotoxicity (mean +/- standard error of the mean, 28.2% 62.05% of cells killed; P<.0001) after exposure to peripheral blood lymphocytes. Ex vivo incubation of autologous tumor-associated lymphocytes with EpCAM-expressing malignant cells in ascites with solitomab resulted in a significant increase in T-cell activation markers and a reduction in the number of viable ovarian tumor cells in ascites (P<.001). CONCLUSIONS: Solitomab may represent a novel, potentially effective agent for the treatment of chemotherapy-resistant ovarian cancers that overexpress EpCAM. (C) 2014 American Cancer Society

Dual HER2/PIK3CA Targeting Overcomes Single-Agent Acquired Resistance in HER2-Amplified Uterine Serous Carcinoma Cell Lines In Vitro

HER2/neu gene amplification and PIK3CA driver mutations are common in uterine serous carcinoma (USC), and may represent ideal therapeutic targets against this aggressive variant of endometrial cancer. We examined the sensitivity to neratinib, taselisib and the combination of the two compounds in in vitro and in vivo experiments using PIK3CA mutated and PIK3CA-wild type HER2/neu amplified USC cell lines. Cell viability and cell cycle distribution were assessed using flow-cytometry assays. Downstream signaling was assessed by immunoblotting. Preclinical efficacy of single versus dual inhibition was evaluated in vivo using two USC-xenografts. We found both single agent neratinib and taselisib to be active but only transiently effective in controlling the in vivo growth of USC xenografts harboring HER2/neu gene amplification with or without oncogenic PIK3CA mutations. In contrast, the combination of the two inhibitors caused a stronger and long lasting growth inhibition in both USC xenografts when compared to single agent therapy. Combined targeting of HER2 and PIK3CA was associated with a significant and dose-dependent increase in the percentage of cells in the G0/G1 phase of the cell cycle and a dose-dependent decline in the phosphorylation of S6. Importantly, dual inhibition therapy initiated after tumor progression in single agent-treated mice was still remarkably effective at inducing tumor regression in both large PIK3CA or pan-ErbB inhibitor-resistant USC xenografts. Dual HER2/PIK3CA blockade may represent a novel therapeutic option for USC patients harboring tumors with HER2/neu gene amplification and mutated or wild type PIK3CA resistant to chemotherapy