bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A54: Evaluation of effect of metformin and its various combinations on epithelial ovarian cancer
Authors: Patel Seema , Singh Neeta
Published: August 2014

Background & objectives: Ovarian cancer is the third most common cause of cancer in Indian women, the most common being epithelial type. Most patients relapse within 1-2 years of treatment and develop resistance to chemotherapy. The identification of new drugs with ability to resensitise ovarian cancer cells to existing chemotherapy has become a major challenge. In this study we have attempted to evaluate the effect of metformin (an antidiabetic drug) in ovarian cancer as it has shown promising effects in other solid tumours.

Methods: Primary culture of ovarian cancer cells was established from ascitic fluid of untreated ovarian cancer patients. The cells were treated with carboplatin, paclitaxel and metformin alone and their various combinations and their ability to induce apoptosis seen. In vitro drug dosage was established using the MTT assay. The control and treated cells were then analysed by flowcytometry.

Results: The mean percentage apoptosis in untreated control cells was 4.9 %( range from4-8%), with metformin for 48 hrs was 12.7 %( 9-16.8%), carboplatin 14.2% (9.9-20%), paclitaxel 16.06% (10-20.5%) , metformin and carboplatin 20.2% (12-28.4%), metformin and paclitaxel 26% (18.2-29%), carboplatin and paclitaxel 22.2% (16-27.3%), metformin carboplatin, paclitaxel combination 49% (46-55%)i.e. maximum.

Interpretation & conclusions: Metformin treatment significantly inhibited the proliferation of primary ovarian cancer cells culture. At the cellular level, metformin interferes with cell cycle leading to G0/G1 or S phase arrest. Besides its anti-neoplastic activity as a single agent, metformin treatment with carboplatin and paclitaxel demonstrated increase apoptosis as compared to single agents alone offering its potential as a therapeutic agent with carboplatin and paclitaxel for epithelial ovarian cancer.

Citation Format: Seema Patel, Neeta Singh. Evaluation of effect of metformin and its various combinations on epithelial ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A54.
Abstract A7: Targeting mutant p53 and cell-cell adhesion in ovarian cancer
Authors: Iwanicki Marcin P. , Novak Marian , Zervantonakis Ioannis K. , Ince Tan A. , Drapkin Ronny , Brugge Joan S.
Published: August 2014

One of the most important challenges in the ovarian cancer research is to identify new molecular pathways that can be targeted to kill ovarian cancer cells. High-grade serous ovarian cancer (HGS-OvCa) cells survive, proliferate, and assemble into multicellular clusters that have a capacity to disseminate within the peritoneum. Therefore, it is important to identify specific molecular mechanisms that can be targeted to block survival, growth, and assembly of ovarian cancer multicellular clusters that metastasize within peritoneum. High-grade ovarian tumors originate from the fallopian tube epithelium (FTE) and almost all have mutations in theTP53 gene. The contribution of various mutant p53 proteins (m-p53) to ovarian cancer and whether targeting mutant p53 –dependent molecular mechanisms in ovarian cancer is poorly understood and of clinical significance. We have developed new methodologies and used them to identify m-p53-dependent pathways that support HGS-OvCa survival, proliferation and assembly of multicellular aggregates under condition mimicking peritoneal suspension. To determine whether mutations in TP53 contribute to the ability of HGS-OvCa cells to survive, proliferate, and assemble into multicellular clusters we introduced different variants of mutant p53 (m-p53) into normal human non-transformed FTE cells. We found that expression of m-p53 variants (R175H; R249S; R273H) in FTE cells promoted survival, growth, and assembly of multicellular clusters under conditions mimicking peritoneal suspension. Interestingly m-p53-driven phenotypes were not induced by the loss of p53 expression; and more importantly, these phenotypes were blocked by the reactivation of p53 pathway with small molecule inhibitor NSC319726. We further found that m-p53 induced phenotypes were dependent on the expression of integrin β 1 (ITGB1). The evidence that activated ITGB1 is enriched at cell's surface of precursors of HGS-OvCa within the fallopian tube and HGS-OvCa isolated from ovarian cancer patients highlighted the relevance of these findings to ovarian cancer. We hypothesize that mutant p53 supports survival, growth, and assembly of multicellular HGS-OvCa clusters through mechanisms in which ITGB1 plays a critical role. Our data indicate that observed phenotypes are the consequence of the m-p53 gain of function mechanisms that are amenable to therapeutic inhibitions and targeting m-p53 in HGS-OvCa might be of clinical significance.

Citation Format: Marcin P. Iwanicki, Marian Novak, Ioannis K. Zervantonakis, Tan A. Ince, Ronny Drapkin, Joan S. Brugge. Targeting mutant p53 and cell-cell adhesion in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A7.
Abstract A74: Microparticles mediate cross-talk between tumoral and endothelial cells and promote the constitution of an angiocrine pro-metastatic niche through Arf6 up regulation
Authors: Pasquier Jennifer , Thawadi Hamda Al. , Kaoud Nadine Abu , Ghiabi Pegah , Maleki Mahtab , Guerrouahen Bella S. , Rafii Arash
Published: August 2014

During the past few years, evidences in the literature point out the crucial role of the microenvironment in tumor growth, resistance to therapy and occurrence of metastatic phenotype. Tumor vessels have been considered for a long time as passive conducts for nutriments but more recently several studies have also demonstrated secretion of pro-tumoral factors by endothelial cells. It seems therefore mandatory to clearly identify the mechanisms mediating cross-talk between tumor cells and endothelial cells.

Here, we hypothetize that tumor cell and endothelium secrete bio-active microparticles (MPs) that are actively uptaken by the other cell type and that are participating to a functional cross-talk. We characterized the cancer cells MPs, using 2 cells lines from breast cancer (MCF7, MDA-MB231) and 2 from ovarian cancer (SKOV3, OVCAR3) and the endothelium secreted MPs using E4orf1-activated endothelium.

Our data show that MPs from mesenchymal-like metastatic cell lines (MDA-MB231 and SKOV3) were able to promote an angiocrine switch of endothelial cells (activation of akt signaling) compared to MPs from epithelial-like cell lines (OVCAR3 and MCF7). The angiocrine switch increased Arf6 expression and functionalized an MP dependent vascular niche enhancing tumor cells pro-metastatic proprieties. We also show that angiocrine endothelial MPs enhanced tumor cells pro-metastatic proprieties and cancer stemness.

All together we demonstrated that cancer cell derived MPs induced or sustain both an angiogenic but also an angiocrine switch of the endothelium. This has great implication in terms of tumor biology as indeed while the emphasis has mainly been on the angiogenic properties, the angiocrine pro-tumoral effect might be the cause for therapeutic resistance as well as residual and recurrent disease.

Citation Format: Jennifer Pasquier, Hamda Al. Thawadi, Nadine Abu Kaoud, Pegah Ghiabi, Mahtab Maleki, Bella S. Guerrouahen, Arash Rafii. Microparticles mediate cross-talk between tumoral and endothelial cells and promote the constitution of an angiocrine pro-metastatic niche through Arf6 up regulation. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A74.
Abstract A84: Metronomic cyclophosphamide, when combined with vaccination, increases the immunogenicity of the vaccine and modulates the tumor microenvironment to provide better anti-tumor activity
Authors: Weir Genevieve M. , Berinstein Neil L. , Hrytsenko Olga , Karkada Mohan , Stanford Marianne M. , Mansour Marc
Published: August 2014

DPX-Survivac is a peptide vaccine targeting the broadly expressed tumor antigen survivin. The vaccine contains a mixture of survivin HLA class I peptides (A1, A2, A3, A24 and B7) formulated in the novel adjuvanting vaccine platform DepoVaxTM. A phase I clinical study performed in advanced ovarian cancer patients (n=19) demonstrated that the combination of metronomic cyclophosphamide (mCPA) and DPX-Survivac exhibited enhanced immune responses by IFN-γ ELISPOT (p<0.015) and increased poly-functional antigen-specific EM/ CM CD8+ T cells, relative to patients treated with vaccine alone. These results were mirrored in a preclinical mouse model in which tumor bearing mice treated with mCPA in combination with a DPX peptide vaccine had increased IFN-γ ELISPOT response and enriched antigen-specific CD8+ T cells. Adoptively transferred T cells from mice treated with the combination of mCPA and vaccine provided a more pronounced anti-tumor effect. Immunophenotyping by flow cytometry indicated that mice treated with mCPA and vaccine had reduced levels of tumor-induced immune suppressor cells, such as myeloid derived suppressor cells, but no effect was seen on regulatory T cells. Analysis of the tumor microenvironment by RT-qPCR revealed that mice treated with combination therapy had increased levels of cytotoxic T lymphocyte (CTL) markers such as granzyme B and IFN-γ. An ovarian tumor model (MOSE) was developed in HLA-A2 transgenic mice to extend these finding to a DPX-survivin vaccine in a relevant animal model. We showed that mCPA increased the levels of CTL markers in the tumor specifically when combined with a DPX-survivin vaccine, in addition to enhancing the immunogenicity of the vaccine. Together, these models allow us to explore novel immune modulator/ vaccine combinations and provide insight into mechanisms that could result in enhanced anti-tumor activity.

Citation Format: Genevieve M. Weir, Neil L. Berinstein, Olga Hrytsenko, Mohan Karkada, Marianne M. Stanford, Marc Mansour. Metronomic cyclophosphamide, when combined with vaccination, increases the immunogenicity of the vaccine and modulates the tumor microenvironment to provide better anti-tumor activity. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A84.
Abstract B27: Melatonin synergistically enhances cisplatin-induced apoptosis via the dephosphorylation of ERK/p90 ribosomal S6 kinase/heat shock protein 27 in SK-OV-3 cells
Authors: Kim Sunghoon , Kim Jihyun , kim bonglee , Kim Junghyo
Published: August 2014

To evaluate melatonin's ability to enhance ovarian cancer cells to cisplatin treatment for ovarian cancer, this study was performed. Melatonin by itself had no significant cytotoxicity against SK-OV-3 cells, while cisplatin suppressed the cell viability in a dose-dependent manner. Combined treatment with cisplatin and melatonin synergistically inhibited the viability of SK-OV-3 cells with the synergism between two drugs (1 > combination index). In contrast, melatonin revealed the protective effect against cisplatin-induced cytotoxicity in OSEN normal ovarian epithelial cells. Cotreatment with cisplatin and melatonin increased the sub-G1 DNA contents and TdT-mediated dUTP nick end-labeling (TUNEL)-positive cells compared with cisplatin control in SK-OV-3 cells, suggesting that melatonin augments cisplatin-induced apoptosis. Consistently, combined treatment of cisplatin and melatonin increased the cleavage of caspase-3 and poly-(ADP-ribose) polymerase (PARP). Importantly, melatonin synergistically inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) along with dephosphorylation of 90-kDa ribosomal S6 kinase (p90RSK) and heat shock protein 27 (HSP27) induced by cisplatin. Furthermore, melatonin remarkably blocked the expression and colocalization of p90RSK and HSP27 by combination treatment with cisplatin. Taken together, our findings demonstrate that melatonin enhances cisplatin-induced apoptosis via the inactivation of ERK/p90RSK/HSP27 cascade in SK-OV-3 cells as a potent synergist to cisplatin treatment.

Citation Format: Sunghoon Kim, Jihyun Kim, bonglee kim, Junghyo Kim. Melatonin synergistically enhances cisplatin-induced apoptosis via the dephosphorylation of ERK/p90 ribosomal S6 kinase/heat shock protein 27 in SK-OV-3 cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B27.
Abstract B31: Aryl hydrocarbon receptor translocation, CYP1A1 induction and ROS formation: pharmacodynamic markers of sensitivity to antitumor Benzothiazole 5F203 in ovarian cancer
Authors: Callero Mariana Alejandra , Luzzani Gabriela , Dios Diana De , Tracey Bradshaw , Perez Andrea Loaiza
Published: August 2014

Ovarian malignancies, the second cause of gynaecological cancer death in developed countries possess poor prognoses. Detected at advanced stages of disease (III and IV), the standard of care is cytoreductive surgery followed by platin- and taxane-based chemotherapy. Intrinsic- or acquired resistance to cytotoxic drugs result in significant risk of recurrence; therefore, the discovery of new molecular targets and more effective therapies remain vital.

2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F203, NSC 703786) lysylamide belongs to a novel mechanistic class of antitumor agents. It elicits activity against ovarian, breast, kidney and colorectal cancer models. We have previously showed 5F203 activates aryl hydrocarbon receptor (AhR) signaling: enhanced CYP1A1 expression and AhR nuclear translocation in sensitive IGROV-1 ovarian cancer cells. This AhR modulation triggers an antiproliferative/pro-apoptotic activity evoking ROS formation, DNA damage and cell cycle arrest prior to apoptosis. In contrast, 5F203 failed to induce CYP1A1 expression, AhR translocation or oxidative stress in 5F203-resistant SKOV-3 cells.

In this work we further investigated 5F 203 antitumor mechanism of action. We found that 5F203 ROS formation was accompanied by JNK, ERK and P38MAPK phosphorylation only in IGROV-1 sensitive cells. In addition, cancer cells have been isolated from ascites fluid of ovarian cancer patients; sensitivity to 5F203 and concurrent AhR signal transduction has been examined. 5F203 induced enhanced CYP1A1 expression, AhR translocation and ROS formation in ascites-isolated ovarian cancer cells that were sensitive to 5F203.

We propose that AhR may represent a new molecular target in the treatment of ovarian tumors and 5F203 may exemplify a potential novel treatment. Finally, our studies demonstrate theranostic pharmacodynamic markers of 5F203 activity and provide additional insight into molecular targets of this novel anticancer agent, which may benefit ovarian cancer patients with limited therapeutic options.

Note: This abstract was not presented at the conference.

Citation Format: Mariana Alejandra Callero, Gabriela Luzzani, Diana De Dios, Bradshaw Tracey, Andrea Loaiza Perez. Aryl hydrocarbon receptor translocation, CYP1A1 induction and ROS formation: pharmacodynamic markers of sensitivity to antitumor Benzothiazole 5F203 in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B31.
Abstract B40: MiR-30c-2-3p participates in a regulatory feedback loop to inhibit the progression of chemoresistant ovarian cancer cells
Authors: Murph Mandi , JIa Wei , Altman Molly , Nguyen Ha
Published: August 2014

Although many patients achieve a period of remission, serous epithelial ovarian carcinoma remains incurable because untreatable chemoresistant disease develops after first-line chemotherapy. The general lack of knowledge in understanding the molecular mechanisms that evolve in chemoresistance and the absence of ‘targetable’ molecules to exploit therapeutically is a major obstacle preventing an improvement in mortality. MicroRNAs (miRNAs) are naturally-produced, small noncoding RNA molecules that modulate gene transcription by fine-tuning messenger RNA (mRNA) expression and acting as mRNA co-repressors or co-activators. The mitogenic lipid, lysophosphatidic acid, and the epidermal growth factor mediate a significant increase in miR-30c-2-3p, which then participates in a regulatory feedback loop to inhibit viability, growth and proliferation of both chemo-sensitive and –resistant cells. Because a single miRNA can target hundreds of transcripts, we wanted to understand which mRNAs are targeted by miR-30c-2-3p and what is the extent of its ability to alter normal processes like survival, growth and proliferation through post-transcriptional modifications. In our study, we uncovered that miR-30c-2-3p targets the oncogene transcript for BCL9, which is a protein that promotes tumor progression, proliferation and metastasis. We hypothesize that the perpetuation of incessant, extracellular, mitogenic signaling overwhelms the anti-growth feedback loop mechanism supported by miR-30c-2-3p. Thus, the growth factor lysophosphatidic acid, which is abundantly present in ascites fluid, is a significant barrier to the successful treatment of chemoresistant ovarian tumors. Our data will demonstrate the effects of lysophosphatidic acid in both in vitro and in vivo models of ovarian cancer. Our long-term goal is to better understand the molecular mechanisms which evolve simultaneously with chemoresistance in ovarian tumor progression.

Citation Format: Mandi Murph, Wei JIa, Molly Altman, Ha Nguyen. MiR-30c-2-3p participates in a regulatory feedback loop to inhibit the progression of chemoresistant ovarian cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B40.
Abstract B52: The bromodomain inhibitor JQ1 enhances cisplatin-mediated cytotoxicity in ovarian cancer cells
Authors: Khabele Dineo , Wilson Andrew J. , Saskowski Jeanette , Hiebert Scott W.
Published: August 2014

Ovarian cancer is the most lethal gynecologic malignancy. The treatment of platinum resistance disease remains an urgent and unmet clinical need. Identification of bromodomain inhibitors to disrupt “reading” of aberrant protein acetylation marks in cancer, leading to down-regulation of lineage-specific oncogenes is an exciting development in epigenetic drug therapy. The oncogenic transcription factor c-MYC (MYC) is amplified in approximately 30-40% of high grade serous ovarian tumors and may be epigenetically deregulated via a “super enhancer” on chromosome 8q24. JQ1, an inhibitor of bromodomain binding, down-regulates MYC expression in MYC-amplified tumors. However, this mechanism appears to be tissue-specific and has not been tested as a method for chemosensitization in ovarian cancer. We hypothesized that JQ1 could be used to enhance cisplatin cytotoxicity in ovarian cancer cells, in part by repression of MYC. Ovarian cancer cell lines were selected after in silico evaluation of publically available, annotated cell line collections. Cell lines with relatively low expression of MYC (IGROV-1 and SKOV3) and relatively high expression, A2780 parental [A2780PAR] and isogenic cisplatin-resistant A2780CP20 cells) were treated with 0.1% DMSO, JQ1, cisplatin or the combination of drugs. Sulforhodamine B (SRB) and clonogenic assays were used to assess effects on cell viability. Apoptosis was evaluated by Western Blot detection of cleaved PARP. Expression of MYC was measured by QPCR and Western Blot. JQ1 reduced cell viability and clonogenicity at sub-micromolar concentrations in the ovarian cancer cell lines examined. Furthermore, JQ1 treatment sensitized ovarian cancer cells, including the resistant A2780CP20, to the growth inhibitory and pro-apoptotic effects of cisplatin. However, the cytotoxic effects of JQ1 were not directly correlated with down-regulation of MYC. First, A2780PAR and A2780CP20 cells expressed the highest basal levels of MYC in our panel, but were not the most sensitive to JQ1-induced anti-tumor effects. Second, JQ1 markedly inhibited MYC expression in A2780PAR, but not A2780CP20 cells, despite relatively similar reduction in growth inhibition by JQ1 alone and combined with cisplatin in these cell lines. Taken together, these novel findings suggest that JQ1 could be used to sensitize ovarian cancer cells to platinum-based therapy. Identifying oncogenic targets of JQ1 other than MYC in ovarian cancer is a priority for further development of bromodomain inhibitors in ovarian cancer.

Citation Format: Dineo Khabele, Andrew J. Wilson, Jeanette Saskowski, Scott W. Hiebert. The bromodomain inhibitor JQ1 enhances cisplatin-mediated cytotoxicity in ovarian cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B52.
Abstract B60: Oovarian mesenchymal stem cells secreted Interleukin-6 promotes the malignant transformation of serous ovarian cancer
Authors: Ding Dah-Ching , Chu Tang-Yuan
Published: August 2014

Purpose: The IL-6/STAT3 signal plays a key role in the progression of serous carcinoma of the ovary. The role of ovarian stroma mesenchymal stem cells involving in this signaling and cancer progression is not known.

Methods: Ovarian mesenchymal stem cells (OvMSC) were derived from ovarian stroma. Surface markers and differentiation ability were characterized. The effect of condition medium (CM) of OvMSC on the transformation of SKOV3 ovarian cancer cells was tested and the level and downstream signalings of IL6 were investigated.

Results: OvMSC had a similar surface marker profiles as bone marrow mesenchymal stem cells, i.e. CD44 (+), CD90 (+) and CD45 (-) and was readily inducible to osteogenic, adipogenic and chondrogenic differentiations. Upon treatment CM of OvMSC, an increase of proliferation, colony formation and tumor sphere formation of SKOV3 cells was noted. The ELISA assay revealed CM of OvMSC had high level of IL-6, which readily activated JAK2 and STAT3 in the cancer cells. Adding of IL-6 blocking antibody to the CM of OvMSC significantly reduced the transformation activity to SKOV3 cells.

Conclusion: IL-6 secreted by OvMSC may be an important transformation signal to the developing ovarian serous carcinoma, the JAK2/STAT3 signaling pathway. The study suggests the possible source of transforming IL-6 from OvMSC in the development of serous ovarian carcinoma.

Citation Format: Dah-Ching Ding, Tang-Yuan Chu. Oovarian mesenchymal stem cells secreted Interleukin-6 promotes the malignant transformation of serous ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B60.
Abstract B69: Preferential transfer of mitochondria from endothelial to cancer cells through tunneling nanotubes modulates chemoresistance
Authors: Pasquier Jennifer , Guerrouahen Bella s. , Thawadi Hamda Al. , Kaoud Nadine Abu , Maleki Mahtab , Foll Frank Le , Rafii Arash
Published: August 2014

Our vision of cancer has changed during the past decades. Indeed tumors are now perceived as complex entities where tumoral and stromal components interact closely. Among the different elements of tumor stroma the cellular component play a primordial role. Bone Marrow derived mesenchymal cells (MSCs) are attracted to tumor sites and support tumor growth. Endothelial cells (ECs) play a major role in angiogenesis. While the literature documents many aspects of the cross talk between stromal and cancer cells, the role of direct hetero-cellular contact is not clearly established.

Recently, Tunneling nanotubes (TnTs) have been shown to support cell-to-cell transfers of plasma membrane components, cytosolic molecules and organelles within cell lines. Herein, we have investigated the formation of heterocellular TnTs between stromal (MSCs and ECs) and cancer cells. We demonstrate that TnTs occur between different cancer cells, stromal cells and cancer-stromal cell lines. We showed that TnTs-like structure occurred in 3D anchorage independent spheroids and also in tumor explant cultures. In our culture condition, TnTs formation occurred after large membrane adhesion. We showed that intercellular transfers of cytoplasmic content occurred similarly between cancer cells and MSCs or ECs, but we highlighted that the exchange of mitochondria occurred preferentially between endothelial cells and cancer cells. We illustrated that the cancer cells acquiring mitochondria displayed chemoresistance.

Our results illustrate the perfusion-independent role of the endothelium by showing a direct endothelial to cancer cell mitochondrial exchange associated to phenotypic modulation. This supports another role of the endothelium in the constitution of the metastatic niche.

Citation Format: Jennifer Pasquier, Bella s. Guerrouahen, Hamda Al. Thawadi, Nadine Abu Kaoud, Mahtab Maleki, Frank Le Foll, Arash Rafii. Preferential transfer of mitochondria from endothelial to cancer cells through tunneling nanotubes modulates chemoresistance. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B69.
Abstract IA16: Targeting cancer stem cells to overcome chemotherapy resistance
Authors: Buckanovich Ronald J.
Published: August 2014

While most ovarian cancer patients will have a complete response with surgery and chemotherapy, the majority will relapse and die of their disease. The high relapse rate in ovarian cancer after complete clinical response is highly consistent with a cancer stem-like cell (CSC) model. The CSC hypothesis suggests that only rare, inherently chemoresistant cancer cells with stem cell like characteristics are capable of proliferating and differentiating to regenerate the various cell types within a tumor, thereby causing relapse of the disease. In theory and in experimental models, the elimination of CSC can overcome chemotherapy resistance. We are developing novel therapies to specifically target ovarian CSC (OvCSC). Aldehyde Dehydrogenase (ALDH) enzymatic activity was one of the first, and remains one of the best supported CSC markers. ALDH enzymes perform numerous critical functions including the biosynthesis of retinoic acid. Our group and others have found that ALDH identifies a population cancer cells with ovarian CSC (OvCSC) activity. Primary human ALDH+ cells initiate and propagate tumors in mice while ALDH-cells do not. ALDH used in combination with the stem cell marker CD133 enriches CSC isolation. ALDH1A+ or ALDH1A1+CD133+ cells in primary tumor samples predict poor prognosis for ovarian cancer patients [9, 11]. ALDH and CD133 are enriched in tumor specimens immediately following chemotherapy [12]. ALDH1A1 is 100 fold upregulated in chemoresistant ovarian cancer cells and ALDH1A knockdown restores chemosensitivity. Finally, normal ovary epithelial stem cells also express ALDH and CD133, and when mutated for p53 and Rb, these cells gain CSC capacity and initiate serous tumors. Taken together these data strongly support a role for ALDH in serous ovarian CSC. Based on the CSC specific function of ALDH and the function of we generated and screened. We have therefore identified and screened dozens of ALDH inhibitors and molecular analogs of known ALDH inhibitors. Using cell lines with well-defined CSC populations, we have identified several compounds which kill cells expressing CSC markers in vitro. CSC die via necrosis. Lead compounds prevent tumor sphere formation in vitro and restrict tumor initiation in vivo. The novel ALDH inhibitors are highly synergistic with chemotherapy and reverse chemotherapy resistance in primary human tumor xenografts. Taken together our data support ALDH as a CSC specific target and identifies novel compounds as potential new therapeutics.

Citation Format: Ronald J. Buckanovich. Targeting cancer stem cells to overcome chemotherapy resistance. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA16.
Abstract IA26: Protective immune networks in ovarian cancer
Authors: Nelson Brad
Published: August 2014

Ovarian cancer is a challenging disease for which new treatments are urgently needed. High-grade serous ovarian cancer is the most common and lethal subtype, with a five-year survival rate of only 30-40%. Nevertheless, patients with evidence of an immune response against their cancer – in particular the presence of tumor-infiltrating T cells – show markedly prolonged survival. We recently showed that B cells also contribute to tumor immunity, in that tumors infiltrated by both B cells and T cells are associated with higher survival rates than seen with T cells alone. Tumor-infiltrating T cells and B cells co-localize in organized structures resembling lymphoid tissue. These structures also contain dendritic cells and show the hallmarks of active antigen presentation and lymphocyte activation. We are investigating the hypothesis that these lymphoid structures are sites of immune surveillance, where tumor antigens are presented to T cells and B cells allowing the immune system to keep check on the evolving cancer genome. To explore this concept, we are assessing tumor-infiltrating T cells for recognition of mutations identified by whole exome sequencing. In one patient undergoing standard chemotherapy, we found an example of a CD8+ T cell response to a point mutation in the HSDL1 gene. The T cell response emerged during first remission, peaked at first recurrence, and then disappeared by second recurrence, shortly before the patient succumbed to her disease. Thus, the immune system actively surveys the tumor genome in patients undergoing standard treatment, but these responses can fail in the absence of immunologic intervention. With better understanding of the lymphocytes and structures involved, it should be possible to enhance these natural surveillance mechanisms to confer protective immunity and further increase patient survival.

Citation Format: Brad Nelson. Protective immune networks in ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA26.
Abstract IA3: In tumor screening for novel targets in papillary serous ovarian cancer
Authors: Baratta Maria Giuseppina , Baratta Maria Giuseppina , Liu Joyce , Liu Joyce , Zwang Yaara , Zwang Yaara , Zwang Yaara , Schinzel Anna , Schinzel Anna , Drapkin Ronny , Drapkin Ronny , Hahn William , Hahn William , Hahn William , Livingston David M. , Livingston David M.
Published: August 2014

In search of new, potential therapeutic target proteins in primary ovarian cancer cells, we have performed in-tumor shRNA screens in an established, human ovarian cancer (ov ca) cell line growing either subcutaneously or intraperitoneally in immunologically incompetent mice. Validation tests were then performed on the confirmed hits in viability/proliferation assays performed, in parallel, in at least two, cultured primary papillary serous ov ca cell strains each of which was generated by direct intraperitoneal injection of primary, patient- derived ov ca cells. The lentiviral shRNA library used contained ~8,000 hairpins, collectively directed against all known human protein kinases and a number of established human oncoproteins. Approximately 40 hits were detected and confirmed in this study, in which the screen involved deep sequencing of DNA isolated from residual tumor material growing in multiple animals. Here the search was for any hairpins that were selectively and specifically depleted from these DNA samples. Currently, we are focusing on two, new hits in this effort with special attention to their effects on primary human ov ca cell tumor formation in nude mice.

Citation Format: Maria Giuseppina Baratta, Maria Giuseppina Baratta, Joyce Liu, Joyce Liu, Yaara Zwang, Yaara Zwang, Yaara Zwang, Anna Schinzel, Anna Schinzel, Ronny Drapkin, Ronny Drapkin, William Hahn, William Hahn, William Hahn, David M. Livingston, David M. Livingston. In tumor screening for novel targets in papillary serous ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA3.
Abstract IA4: A dualistic model of ovarian carcinogenesis
Authors: Kurman Robert J.
Published: August 2014

Recent morphologic, immunohistochemical and molecular genetic studies have led to the development of a new paradigm for the pathogenesis and origin of epithelial ovarian cancer (EOC) based on a dualistic model of carcinogenesis that divides EOC into two broad categories designated type I and type II. Type I tumors are comprised of low-grade serous, low-grade endometrioid, clear cell and mucinous carcinomas and Brenner tumors. They are generally indolent, present in stage I (tumor confined to the ovary) and are characterized by specific mutations, including KRAS, BRAF, ERBB2, CTNNB1, PTEN PIK3CA, ARID1A, and PPPR1A, which target specific cell signaling pathways. Type I tumors rarely harbor TP53 and are relatively stable genetically. Type II tumors are comprised of high-grade serous, high-grade endometrioid, malignant mixed mesodermal tumors (carcinosarcomas) and undifferentiated carcinomas. They are aggressive, present in advanced stage, and have a very high frequency of TP53 mutations but rarely harbor the mutations detected in type I tumors. In addition, type II tumors have molecular alterations that perturb expression of BRCA either by mutation of the gene or by promotor methylation. A hallmark of these tumors is that they are genetically highly unstable. Recent studies strongly suggest that fallopian tube epithelium (benign or malignant) that implants on the ovary is the source of low-grade and high-grade serous carcinoma rather than the ovarian surface epithelium as previously believed. Similarly, it is widely accepted that endometriosis is the precursor of endometrioid and clear cell carcinomas and as endometriosis is thought to develop from retrograde menstruation these tumors can also be regarded as involving the ovary secondarily. The origin of mucinous and transitional cell (Brenner) tumors is still not well established, although recent data suggest a possible origin from transitional epithelial nests located in paraovarian locations at the tubo-peritoneal junction. Thus, it now appears that type I and type II ovarian tumors develop independently along different molecular pathways, and that both types develop outside the ovary and involve it secondarily. If this concept is confirmed it leads to the conclusion that the only true primary ovarian neoplasms are gonadal stromal and germ cell tumors analogous to testicular tumors. This new paradigm of ovarian carcinogenesis has important clinical implications. By shifting the early events of ovarian carcinogenesis to the fallopian tube and endometrium instead of the ovary, prevention approaches, for example, salpingectomy with ovarian conservation, may play an important role in reducing the burden of ovarian cancer while preserving hormonal function and fertility.

Citation Format: Robert J. Kurman. A dualistic model of ovarian carcinogenesis. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA4.
Abstract IA6: Murine models of nonserous ovarian cancer: Effects of mutant Trp53, Pik3ca, and Arida1a in a model of endometrioid carcinoma based on Wnt and PI3K/Akt pathway defects
Authors: Cho Kathleen R. , Wu Rong , Zhai Yali , Sakaguchi Isao
Published: August 2014

A dualistic pathway model of ovarian carcinoma (OvCA) pathogenesis has been proposed in which type I OvCAs are low grade, genetically stable, and relatively more indolent than type II OvCAs, most of which are high-grade serous carcinomas. Endometrioid OvCA (EOC) is a prototypical type I tumor, often harboring mutations that affect the Wnt and phosphatidylinositol 3-kinase/AKT/mTOR signaling pathways. Molecular and histopathologic analyses indicate type I and II OvCAs share overlapping features, and a subset of EOCs may undergo type I→type II progression accompanied by acquisition of somatic TP53 or PIK3CA mutations. We used a murine model of EOC initiated by conditional inactivation of the Apc and Pten tumor suppressor genes to investigate mutant Trp53 or Pik3ca alleles as key drivers of type I→type II OvCA progression. In the mouse EOC model, the presence of somatic Trp53 or Pik3ca mutations resulted in shortened survival and more widespread metastasis. In contrast, bi-allelic inactivation of Arid1a in addition to Apc and Pten actually prolonged survival and tumors with Arid1a inactivation showed more epithelial differentiation than their counterparts with intact Arid1a alleles. Our findings indicate that the adverse prognosis associated with TP53 and PIK3CA mutations in human cancers can be functionally replicated in mouse models of type I→type II OvCA progression. Moreover, the models should represent a robust platform for assessment of the contributions of Trp53, Pik3ca, and Arid1a mutations to the response of EOCs to conventional and targeted drugs.

Citation Format: Kathleen R. Cho, Rong Wu, Yali Zhai, Isao Sakaguchi. Murine models of nonserous ovarian cancer: Effects of mutant Trp53, Pik3ca, and Arida1a in a model of endometrioid carcinoma based on Wnt and PI3K/Akt pathway defects. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr IA6.
Abstract A250: ABT-414: An anti-EGFR antibody-drug conjugate as a potential therapeutic for the treatment of patients with squamous cell tumors.
Authors: Phillips Andrew C. , Boghaert Erwin R. , Vaidya Kedar S. , Ansell Peter J. , Shalinsky David R. , Zhang Yumin , Voorbach Martin J. , Mudd Sarah , Holen Kyle D. , Humerickhouse Rod A. , Reilly Edward B.
Published: August 2014

ABT-414 is an antibody-drug conjugate (ADC) comprised of an anti-EGFR antibody (ABT-806) conjugated to the potent cytotoxic monomethylauristatin F. ABT-414 binds a unique epitope of EGFR which is largely inaccessible when EGFR is expressed at physiological levels but is accessible in tumors that express EGFRde2-7 [also referred to as EGFR variant III (EGFRvIII)] and in tumors with wild-type amplified EGFR or excessive wild-type EGFR activation. These properties of ABT-414 should limit the effects of the toxin on normal tissues. ABT-414 is highly effective in both mutant and wild-type EGFR-positive human tumor xenografts in mice producing complete regressions and cures observed in the most sensitive models. Squamous cell tumors display a relatively high expression of EGFR. Immunohistochemical analysis reveals >70% of squamous lung and esophageal cancers and >90% of oral cavity tumors show moderate to strong staining for EGFR. Given the high unmet need in these patients and the in vivo data supporting improved ABT-414 efficacy in tumors with high EGFR expression, a Phase I/IIa study evaluating the safety, pharmacokinetics and efficacy of ABT-414 in subjects with EGFR-positive, refractory solid tumors has been initiated with a phase IIa expansion at the MTD in squamous NSCLC. Additionally, this study will evaluate the use of SPECT imaging with an indium-111-labeled parental antibody (ABT-806i) as a predictive tool for patient response. Tumor uptake by ABT-806i SPECT imaging correlates with antitumor response in xenograft models, and ABT-806i has been shown to effectively target tumor sites in select cancer patients. A fluorescent in situ hybridization (FISH) probe to detect EGFR amplification and EGFR IHC are also being evaluated with the goal of identifying patients who are most likely to respond to ABT-414 treatment.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):A250.

Citation Format: Andrew C. Phillips, Erwin R. Boghaert, Kedar S. Vaidya, Peter J. Ansell, David R. Shalinsky, Yumin Zhang, Martin J. Voorbach, Sarah Mudd, Kyle D. Holen, Rod A. Humerickhouse, Edward B. Reilly. ABT-414: An anti-EGFR antibody-drug conjugate as a potential therapeutic for the treatment of patients with squamous cell tumors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr A250.
Abstract B182: Utilization of quantitative multiplex immunofluorescence to assess biomarkers in ovarian cancer; ability to create an objective phenotype with respect to outcome.
Authors: Cardenas-Goicoechea Joel , Long Nguyen , Kalir Tamara , Donovan Michael J.
Published: August 2014

Introduction:Ovarian cancer is the fifth most common cause of cancer deaths among women with the majority of cases diagnosed at an advanced stage where therapeutic options are limited to surgical resection and adjuvant platinum-based chemotherapy regimens. Given the paucity of reliable tissue biomarkers to predict response to therapy, we used a validated quantitative multiplex immunofluorescent (QMIF)platform on formalin-fixed, paraffin-embedded (FFPE) ovarian tissues to quantify biomarker expression patterns and assessed association with outcome.

Methods: 89 patients were evaluated using tissue microarrays consisting of three 0.6mm tumor cores per diagnostic specimen; fallopian tubes and four different ovarian cell lines were included as pos/neg controls. CK7, VEGF, PERK1/2 and TP53 were evaluated with QMIF, with individual and combined antibody features constructed utilizing intensity and area values. Kaplan-Meier with log-rank test along with multivariate Cox proportional hazards model were employed to determine biomarker assocation with respect to overall (OS) and progression free survival (PFS).

Results: Mean age 59yrs, 80% serous, 88% Grade 3 and 85% >/= Stage IIIC. Median follow-up 32m; 5-year OS 51% and platinum resistance 54%. In multivariate analysis CK7+TP53+ was an independent prognostic marker for both PFS and OS (p-value <0.001 and 0.04), i.e greater amounts associated with decreased survival. By contrast, increased levels of PERK1/2 were associated with a decreased tumor recurrence and increased platinum sensitivity (p=0.020 and 0.006) while increasing amounts of VEGF were associated with greater tumor recurrence (p=0.004) as well as platinum sensitvity (p=0.03).Conclusion: Quantitative assessment of TP53, PERK1/2 and VEGF provides valuable (biological) information with respect to chemoresponse and tumor recurrence. The application of QMIF to biomarker investigation will provide another level of complexity to tumor phenotypic characterization which is currently not available using standard subjective, chromogenic IHC assays.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B182.

Citation Format: Joel Cardenas-Goicoechea, Nguyen Long, Tamara Kalir, Michael J. Donovan. Utilization of quantitative multiplex immunofluorescence to assess biomarkers in ovarian cancer; ability to create an objective phenotype with respect to outcome. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B182.
Abstract B215: Correlation of PSMA ADC exposure with reduction in tumor growth rate determined using serial PSA measurements from a Phase I clinical trial.
Authors: Rotshteyn Yakov , Mercier F , Bruno R , Stambler Nancy , Israel Robert J. , Wong Vivien
Published: August 2014

Background: PSMA ADC is a fully humanized antibody to PSMA conjugated to the potent microtubule disrupting agent monomethyl auristatin E (MMAE). The safety and PK of PSMA ADC as well as changes in PSA levels were evaluated in a Phase I dose escalation study in patients with taxane-refractory metastatic castration-resistant prostate cancer (mCRPC) (PSMA ADC 1301). Stein et al. (2010) has previously demonstrated correlation between growth rate derived from serial PSA measurements with survival in patients with mCRPC and suggested that growth rate could serve as a novel endpoint indicative of response to therapy and overall survival.

Methods: The PK parameters for PSMA ADC, Total antibody (Ab) and free MMAE obtained from PSMA ADC Study 1301 (N=52) were calculated using non-compartmental analysis. The final data set contains 253 longitudinal PSA observations from 52 subjects dosed with 0.4-2.8 mg/kg PSMA ADC. The Stein model was re-expressed as a 7-parameter population model to describe the longitudinal PSA data which includes: Baseline PSA level (Y0), PSA decrease rate (D), PSA increase rate (G), inter-patient variability for Y0, G and D respectively, and residual variance. Model parameters were estimated using Phoenix/NLME®. Exposure-efficacy relationships and correlation between G and covariates were determined.

Results: PSMA ADC, Total Ab, and MMAE exposure increased linearly with increasing PSMA ADC dose. Longitudinal PSA data were correctly fitted to the re-expressed Stein model. G continuously decreased with increasing PSMA ADC exposure, suggesting an exposure dependent drug effect. There was no apparent saturation of this effect at the maximum observed exposure, and no influence of age, baseline albumin and ALT/AST levels on G was evident.

Conclusions: In a Phase I study where PSMA ADC (0.4-2.8 mg/kg) was administered to patients with mCRPC, we observed a correlation of PSMA ADC exposure with the reduction of G, suggesting that PSMA ADC may provide dose-dependent therapeutic benefit to subjects with mCRPC.

Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B215.

Citation Format: Yakov Rotshteyn, F Mercier, R Bruno, Nancy Stambler, Robert J. Israel, Vivien Wong. Correlation of PSMA ADC exposure with reduction in tumor growth rate determined using serial PSA measurements from a Phase I clinical trial. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B215.