Mouse Model Of Ovarian Cancer Research Articles

Directed evolution of cyclic peptides for inhibition of autophagy.

In recent decades it has become increasingly clear that induction of autophagy plays an important role in the development of treatment resistance and dormancy in many cancer types. Unfortunately, chloroquine (CQ) and hydroxychloroquine (HCQ), two autophagy inhibitors in clinical trials, suffer from poor pharmacokinetics and high toxicity at therapeutic dosages. This has prompted intense interest in the development of targeted autophagy inhibitors to re-sensitize disease to treatment with minimal impact on normal tissue. We utilized Scanning Unnatural Protease Resistant (SUPR) mRNA display to develop macrocyclic peptides targeting the autophagy protein LC3. The resulting peptides bound LC3A and LC3B—two essential components of the autophagosome maturation machinery—with mid-nanomolar affinities and disrupted protein–protein interactions (PPIs) between LC3 and its binding partners in vitro. The most promising LC3-binding SUPR peptide accessed the cytosol at low micromolar concentrations as measured by chloroalkane penetration assay (CAPA) and inhibited starvation-mediated GFP-LC3 puncta formation in a concentration-dependent manner. LC3-binding SUPR peptides re-sensitized platinum-resistant ovarian cancer cells to cisplatin treatment and triggered accumulation of the adapter protein p62 suggesting decreased autophagic flux through successful disruption of LC3 PPIs in cell culture. In mouse models of metastatic ovarian cancer, treatment with LC3-binding SUPR peptides and carboplatin resulted in almost complete inhibition of tumor growth after four weeks of treatment. These results indicate that SUPR peptide mRNA display can be used to develop cell-penetrating macrocyclic peptides that target and disrupt the autophagic machinery in vitro and in vivo.

A Luminacin D Analog HL142 Inhibits Ovarian Tumor Growth and Metastasis by Reversing EMT and Attenuating the TGFβ and FAK Pathways.

Epithelial to mesenchymal transition (EMT) is known to contribute to tumor metastasis and chemoresistance. Reversing EMT using small molecule inhibitors to target EMT associated gene expression represents an effective strategy for cancer treatment. The purpose of this study is to test whether a new luminacin D analog HL142 reverses EMT in ovarian cancer (OC) and has the therapeutic potential for OC. We chemically synthesized HL142 and tested its functions in OC cells in vitro and its efficacy in inhibiting ovarian tumor growth and metastasis in vivo using orthotopic OC mouse models. We first demonstrate that ASAP1 is co-amplified and interacts with the focal adhesion kinase (FAK) protein in serous ovarian carcinoma. HL142 inhibits ASAP1 and its interaction protein FAK in highly invasive OVCAR8 and moderately invasive OVCAR3 cells. HL142 inhibits EMT phenotypic switch, accompanied by upregulating epithelial marker E-cadherin and cytokeratin-7 and downregulating mesenchymal markers vimentin, β-catenin, and snail2 in both cell lines. Functionally, HL142 inhibits proliferation, colony formation, migration, and invasion. HL142 also sensitizes cell responses to chemotherapy drug paclitaxel treatment and inhibits ovarian tumor growth and metastasis in orthotopic OC mouse models. We further show that HL142 attenuates the TGFβ and FAK pathways in vitro using OC cells and in vivo using orthotopic mouse models.

Chimeric Antigen receptor-T (CAR-T) cells targeting Epithelial cell adhesion molecule (EpCAM) can inhibit tumor growth in ovarian cancer mouse model.

Ovarian cancer (OC) is one of the most lethal solid tumors with poor prognosis. In 2017, two chimeric antigen receptor-T (CAR-T) cell drugs were approved by the U.S. Food and Drug Administration (FDA), and continuously optimized CAR-T cells therapy might be the novel hope for OC patient. EpCAM are known to be over-expressed in OC cells and could be targeted by CAR-T cells. However, the feasibility of using EpCAM-CAR-T cells to treat OC still needs to be verified. We engineered the 3rd-generation EpCAM-CAR containing a single-chain variable fragment (scFv) EpCAM-scFv that targeting EpCAM, a CD8 transmembrane domain, the costimulatory domains from both CD28 and 4-1BB, and activating domain CD3ζ and then transduced the CAR into T-cells via lentivirus. In addition, the cytotoxicity and cytokine releasing ability of the EpCAM-CAR-T cells against OC cell SKOV3 were verified in vitro. The in vivo data also showed that EpCAM-CAR-T cells significantly reduced the tumor size in OC xenograft mouse models. The anti-tumor activity of EpCAM-CAR-T cells against OC in vitro and in vivo indicated that the CAR-T might provide a promising therapeutic approach to OC.

Establishment of a Mouse Ovarian Cancer and Peritoneal Metastasis Model to Study Intraperitoneal Chemotherapy

Simple SummaryIntraperitoneal chemotherapy (IPC) is a locoregional treatment option in patients with peritoneal metastases (PM). Small animal models are valuable research tools allowing for rapid, reproducible, and inexpensive study and optimization of different forms of IPC. Here, we present a mouse model of ovarian cancer-derived PM and demonstrate its suitability for various modes of IPC, including pressurized intraperitoneal chemotherapy (PIPAC) using a micro-nozzle for aerosolized drug delivery.Intraperitoneal chemotherapy (IPC) is a locoregional treatment option in patients with peritoneal metastases (PM). Here, we present an ovarian cancer (OC)-derived PM mouse model for the study of different forms of IPC. Xenograft cell proliferation (luciferase-transfected OVCAR3 and SKOV3 clones) and growth kinetics were assessed using PET scan, bioluminescence imaging (BLI), and histological tumor analysis. Liquid IPC was achieved by intraperitoneal injection with/without capnoperitoneum (6–7 mmHg). Pressurized intraperitoneal aerosol chemotherapy (PIPAC) was mimicked using an intratracheal drug aerosol administration system (micro-nozzle), which, as demonstrated by ex vivo granulometric analysis using laser diffraction spectrometry, produced a polydisperse, bimodal aerosol with a volume-weighted median diameter of (26.49 ± 2.76) µm. Distribution of Tc-99m-labeled doxorubicin in mice was characterized using SPECT and was dependent on the delivery mode and most homogeneous when the micro-nozzle was used. A total of 2 mg doxorubicin per kg body weight was determined to be the optimally effective and tolerable dose to achieve at least 50% tumor reduction. Repeated PIPAC (four times at seven-day-intervals) with doxorubicin in SKOV3-luc tumor-bearing mice resulted in halted tumor proliferation and tumor load reduced after the second round of PIPAC versus controls and the number of tumor nodules was significantly reduced (27.7 ± 9.5 vs. 57.3 ± 9.5; p = 0.0003). Thus, we established the first mouse model of OC PM for the study of IPC using a human xenograft with SKOV3 cells and an experimental IPC setup with a miniaturized nozzle. Repeated IPC was feasible and demonstrated time-dependent anti-tumor activity.

Non-target genetic manipulation induces rhabdomyosarcoma in KrasPten-driven mouse model of ovarian cancer.

BackgroundGenetically engineered mice are ideal models to advance our understanding the tumorigenesis of ovarian cancer. Our original objective was to establish an ovarian cancer model induced by Kras activation and Pten deletion. However, proficiently establishing the model remains a technical problem, which limits its application.MethodsWe established the Kras activation/Pten deletion-induced mouse model of ovarian cancer by injecting Cre recombinase-expressing adenovirus in the ovarian bursa. PCR analysis, Western blotting, and immunohistochemistry staining were performed to verify the alteration of conditional genes. We detected expression of canonical molecular markers in order to examine the origin of the tumors.ResultsSubcutaneous lumps developed accidentally in mice with ovarian cancer, as early as 2 weeks post in vivo genetic manipulation, far before the destructive growth of ovarian cancer. PCR analysis confirmed the efficient Cre-mediated recombination of Kras and Pten in tumor tissues, which are consistent with the activation of the MAPK and PI3K/Akt/mTOR pathways. Histomorphological and histological analysis showed that the lumps were actually rhabdomyosarcoma (RMS). We confirmed that the leakage of adenovirus transformed healthy adjacent tissues into RMS.ConclusionsAvoiding accidental exposure of non-target tissues to adenovirus is crucial to successfully establish the ovarian cancer mouse model. Moreover, non-specific genetic manipulations can induce the development of RMS.

Epigenomic Reprogramming toward Mesenchymal-Epithelial Transition in Ovarian-Cancer-Associated Mesenchymal Stem Cells Drives Metastasis

SUMMARYA role for cancer cell epithelial-to-mesenchymal transition (EMT) in cancer is well established. Here, we show that, in addition to cancer cell EMT, ovarian cancer cell metastasis relies on an epigenomic mesenchymal-to-epithelial transition (MET) in host mesenchymal stem cells (MSCs). These reprogrammed MSCs, termed carcinoma-associated MSCs (CA-MSCs), acquire pro-tumorigenic functions and directly bind cancer cells to serve as a metastatic driver/chaperone. Cancer cells induce this epigenomic MET characterized by enhancer-enriched DNA hypermethylation, altered chromatin accessibility, and differential histone modifications. This phenomenon appears clinically relevant, as CA-MSC MET is highly correlated with patient survival. Mechanistically, mirroring MET observed in development, MET in CA-MSCs is mediated by WT1 and EZH2. Importantly, EZH2 inhibitors, which are clinically available, significantly inhibited CA-MSC-mediated metastasis in mouse models of ovarian cancer.

The hidden role of paxillin: localization to nucleus promotes tumor angiogenesis.

Paxillin (PXN), a key component of the focal adhesion complex, has been associated with cancer progression, but the underlying mechanisms are poorly understood. The purpose of this study was to elucidate mechanisms by which PXN affects cancer growth and progression, which we addressed using cancer patient data, cell lines, and orthotopic mouse models. We demonstrated a previously unrecognized mechanism whereby nuclear PXN enhances angiogenesis by transcriptionally regulating SRC expression. SRC, in turn, increases PLAT expression through NF-ĸB activation; PLAT promotes angiogenesis via LRP1 in endothelial cells. PXN silencing in ovarian cancer mouse models reduced angiogenesis, tumor growth, and metastasis. These findings provide a new understanding of the role of PXN in regulating tumor angiogenesis and growth.

Novel Chimeric Poxvirus CF17 Improves Survival in a Murine Model of Intraperitoneal Ovarian Cancer Metastasis

Despite improvements in surgical techniques and chemotherapy, ovarian cancer remains the most lethal gynecologic cancer. Thus, there is an urgent need for more effective therapeutics, particularly for chemo-resistant peritoneal ovarian cancer metastases. Oncolytic virotherapy represents an innovative treatment paradigm; however, for oncolytic viruses tested from the last generation of genetically engineered viruses, the therapeutic benefits have been modest. To overcome these limitations, we generated a chimeric poxvirus, CF17, through the chimerization of nine species of orthopoxviruses. Compared with its parental viruses, CF17 has demonstrated superior oncolytic characteristics. Here, we report the oncolytic potential of CF17 in ovarian cancer. Replication of CF17 and its resulting cytotoxicity were observed at multiplicities of infection (MOIs) as low as 0.001 in human and mouse cancer cell lines in vitro. Furthermore, CF17 exerted potent antitumor effects in a syngeneic mouse model of ovarian cancer at doses as low as 6 × 106 plaque-forming units. Together, these data merit further investigation of the potential use of this novel chimeric poxvirus as an effective treatment for aggressive intraperitoneal ovarian cancer.

Targeting one-carbon metabolism in syngeneic mouse model of BRCA-mutated high-grade serous ovarian cancer

Objective: In evaluating the next generation of targeted therapies in high-grade serous ovarian cancer (HGSOC), relevant mouse models that recapitulate human disease and have a functioning immune system are needed. Our previous work has identified novel 1-carbon (C1) inhibitors, which are transported by folate receptor alpha (FRα), a receptor shown to be over-expressed in HGSOC. Based upon potent in vivo efficacy in an immuno-compromised mouse model, we sought to investigate this series of FRα-delivered therapies using p53/BRCA-mutated HGSOC syngeneic mouse models (BR5 and BRluc).

Chemopreventive effect of progestin and vitamin D in the mogp-TAG ovarian cancer mouse model

Objective: Growing evidence suggests the fallopian tube epithelium harbors the precursor for high-grade serous ovarian cancer, creating opportunities for targeting the fallopian tube for effective chemoprevention. Animal and human evidence has shown that progestins confer potent cancer preventive effects in the gynecologic tract by activating molecular pathways that clear genetically damaged cells. in addition, it has been shown in vitro that the potency of progestins can be enhanced with vitamin D.

ONC201 has anti-tumorigenic activity in obesity-driven epithelial ovarian cancer

Objective: ONC201 is an orally bioavailable dopamine receptor 2 antagonist that has demonstrated antitumorigenic activity without significant toxicity in phase 1 and 2 trials. Thus, we evaluated the antitumorigenic effects of ONC201 in ovarian cancer (OC) cell lines and a high-grade serous OC mouse model [K18-gT121+/-; p53fl/fl; Brca1fl/fl (KpB)] using both obese and lean mice.

Mechanistic Insights Into the Anticancer Properties of the Auranofin Analog Au(PEt3)I: A Theoretical and Experimental Study.

Au(PEt3)I (AF-I hereafter), the iodide analog of the FDA-approved drug auranofin (AF hereafter), is a promising anticancer agent that produces its pharmacological effects through interaction with non-genomic targets such as the thioredoxin reductase system. AF-I is endowed with a very favorable biochemical profile showing potent in vitro cytotoxic activity against several cancer types including ovarian and colorectal cancer. Remarkably, in a recent publication, some of us reported that AF-I induces an almost complete and rapid remission in an orthotopic in vivo mouse model of ovarian cancer. The cytotoxic potency does not bring about highly severe side effects, making AF-I very well-tolerated even for higher doses, even more so than the pharmacologically active ones. All these promising features led us to expand our studies on the mechanistic aspects underlying the antitumor activity of AF-I. We report here on an integrated experimental and theoretical study on the reactivity of AF-I, in comparison with auranofin, toward relevant aminoacidic residues or their molecular models. Results point out that the replacement of the thiosugar moiety with iodide significantly affects the overall reactivity toward the amino acid residues histidine, cysteine, methionine, and selenocysteine. Altogether, the obtained results contribute to shed light into the enhanced antitumoral activity of AF-I compared with AF.

Zinc regulates primary ovarian tumor growth and metastasis through the epithelial to mesenchymal transition

BackgroundThe trace element zinc plays an indispensable role in human health and diseases including cancer due to its antioxidant properties. While zinc supplements have been used for cancer prevention, zinc is also a risk factor for cancer development. It is still unclear how zinc plays a role in ovarian cancer. MethodsTo understand how zinc contributes to ovarian tumor growth and metastasis, we examined whether zinc contributes to tumor metastasis by regulating epithelial to mesenchymal transition (EMT) using ovarian cancer cells in vitro. Cell migration and invasion were examined using transwell plates and EMT markers were examined using Western blot. Primary ovarian tumor growth and metastasis were assessed using orthotopic ovarian cancer mouse models in vivo. ResultsZinc promoted EMT, while TPEN (N, N, N’, N’-tetrakis-(2-pyridylmethyl)-ethylenediamine), a membrane-permeable selective zinc chelator, inhibited EMT in a dose dependent manner in ovarian cancer cells. Moreover, zinc promoted ovarian cancer cell migration and invasion, while TPEN inhibited cell migration and invasion. Zinc activated expression of the metal response transcriptional factor-1 (MTF-1), while TPEN inhibited MTF-1 expression in a dose dependent manner. Knockout of MTF-1 inhibited zinc-induced cell migration, invasion and augmented the inhibitory effect of TPEN on cell migration and invasion. Loss of MTF-1 attenuated zinc-induced ERK1/2 and AKT activation and augmented the effect of TPEN in attenuating the ERK1/2 and AKT pathways. TPEN effectively inhibited primary ovarian tumor growth and metastasis in an orthotopic ovarian cancer mouse model by suppressing EMT. Conclusionzinc contributes to ovarian tumor metastasis by promoting EMT through a MTF-1 dependent pathway. Zinc depletion by TPEN may be a novel approach for ovarian cancer therapy by inhibiting EMT and attenuating the ERK1/2 and AKT pathways.

Knockout of EGFL6 by CRISPR/Cas9 Mediated Inhibition of Tumor Angiogenesis in Ovarian Cancer.

Tumor angiogenesis plays an important role in the progression and metastasis of ovarian cancer. EGFL6 protein is highly expressed in ovarian cancer and has been proposed to play an important role in promoting tumor angiogenesis. Here, a CRISPR/Cas9 system was used to knockout the EGFL6 gene in the ovarian cancer cell line SKOV3, using specific guide RNA targeting the exons of EGFL6. The knockout of EGFL6 markedly inhibited the proliferation, migration, and invasion of SKOV3 cells, as well as promoted apoptosis of tumor cells. In the nude mouse model of ovarian cancer, knockout of EGFL6 remarkably inhibited tumor growth and angiogenesis. The transcript profile assays detected 4,220 differentially expressed genes in the knockout cells, including 87 genes that were correlated to proliferation, migration, invasion, and angiogenesis. Moreover, Western blotting confirmed that EGFL6 knockout downregulated the FGF-2/PDGFB signaling pathway. Thus, the results of this study indicated that EGFL6 could regulate cell proliferation, migration, and angiogenesis in ovarian cancer cells by regulating the FGF-2/PDGFB signaling pathway.

E2F8 Induces Cell Proliferation and Invasion through the Epithelial-Mesenchymal Transition and Notch Signaling Pathways in Ovarian Cancer.

Background: Despite the recent research implicating E2F8 (E2F Transcription Factor 8) in cancer, the role of E2F8 in the progression of ovarian cancer has remained unclear. Hence, we explored the bio-functional effects of E2F8 knockdown on ovarian cancer cell lines in vitro and in vivo. Methods: The expression of E2F8 was compared between ovarian cancer and noncancer tissues, and its association with the progression-free survival of ovarian cancer patients was analyzed. To demonstrate the function of E2F8 in cell proliferation, migration, and invasion, we employed RNA interference to suppress E2F8 expression in ovarian cancer cell lines. Finally, the effect of E2F8 knockdown was investigated in a xenograft mouse model of ovarian cancer. Results: Ovarian cancer tissue exhibited significantly higher E2F8 expression compared to that of normal ovarian tissue. Clinical data showed that E2F8 was a significant predictor of progression-free survival. Moreover, the prognosis of the ovarian cancer patients with high E2F8 expression was poorer than that of the patients with low E2F8 expression. In vitro experiments using E2F8-knockdown ovarian cancer cell lines demonstrated that E2F8 knockdown inhibited cell proliferation, migration, and tumor invasion. Additionally, E2F8 was a potent inducer and modulator of the expression of epithelial–mesenchymal transition and Notch signaling pathway-related markers. We confirmed the function of E2F8 in vivo, signifying that E2F8 knockdown was significantly correlated with reduced tumor size and weight. Conclusions: Our findings indicate that E2F8 is highly correlated with ovarian cancer progression. Hence, E2F8 can be utilized as a prognostic marker and therapeutic target against ovarian malignancy.

Endothelial p130cas Confers Resistance to Anti-Angiogenesis Therapy

Adaptive resistance to vascular endothelial growth factor (VEGF)–targeted therapies occurs frequently among cancer patients. To investigate the underlying mechanisms, we established an array of orthotopic mouse models of ovarian cancer with adaptive resistance to anti-VEGF antibodies (AVAs). Genomic profiling showed an important role of endothelial p130cas in AVA resistant tumors. AVA treatment induced internalization of a p130cas/VEGFR2/TNKS1BP1 (a tankyrase-1–binding protein) complex in endothelial cells and initiated cell death and autophagy; knockdown of LC3B or caspase-10 reversed cells’ resistance to AVA treatment. Targeting host p130cas reduced the growth of AVA-resistant orthotopic ovarian tumors. Genomic ablation of vascular p130cas in p130casflox/floxTie2Cre mice significantly prolonged survival of mice carrying syngeneic ovarian tumors with adaptive resistance to AVA therapy. In ovarian cancer patients, higher p130cas expression in tumor-associated vasculature was associated with higher mortality. Collectively, these findings have important implications to guide future therapeutic strategies to overcome resistance to anti-angiogenic therapy.

Abstract 1407: MicroRNA-18a targeting inhibits the tumor growth of cisplatin-resistant ovarian cancer

Abstract Platinum-based therapy remains as the front-line treatment for ovarian cancer. However, despite initial response to treatment, most patients develop platinum resistance and eventually succumb to the malignancy. In an attempt to identify novel targets in cisplatin-resistant ovarian cancer, we studied the role of the microRNA-18a-5p (miR-18a) in cisplatin-resistant ovarian cancer. miR-18a is part of the vastly researched miR-17-92 cluster. Although most members of this cluster have been associated with pro-tumorigenic roles in several cancers, recent findings suggest that miR-18a plays a tumor-suppressive role in ovarian cancer. However, the specific role of miR-18a in platinum resistance has yet to be elucidated. In this study, Real-Time PCR analysis was performed to measure the levels of miR-18a in several ovarian cancer cell lines. We found miR-18a downregulation in cisplatin-resistant ovarian cancer cells relative to their sensitive counterparts. Therefore, we assessed the effect of miR-18a upregulation by oligonucleotide microRNA mimics (OMM) in tumor growth using a xenograft mouse model of cisplatin-resistant ovarian cancer. As ovarian tumors have been shown to overexpress the Folate Receptor α (FRα), we used nanoliposomes conjugated to folic acid as vehicles to deliver the OMMs. Following intraperitoneal injections of OMM-loaded liposomes (twice per week for three weeks), there was a significant decrease in tumor weight of miR-18a-OMM treated mice in comparison to the control-OMM group. Moreover, immunohistochemical analysis was performed on the mice tumor tissues to assess the levels of cell proliferation and angiogenesis markers (ki67 and CD31, respectively). Our study suggests that miR-18a halts cisplatin-resistant ovarian cancer tumor progression. This work was supported by the RCMI grant: U54 MD007600, UPR Comprehensive Cancer Center and NIGMS-RISE R25-GM061838. Citation Format: Blanca Iris Quiñones-Díaz, Jeyshka M. Reyes-González, Fatma Valiyeva, Pablo E. Vivas-Mejía. MicroRNA-18a targeting inhibits the tumor growth of cisplatin-resistant ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1407.

Abstract 4184: Genetic and pharmacological disruption of survivin suppressed primary and metastatic tumor growth by attenuating TGFB pathway in ovarian cancer

Abstract Introduction: Survivin, a member of the inhibitor of apoptosis family, is upregulated in multiple cancers including ovarian cancer, but is rarely detectable in normal tissues. Therefore, it is a potential drug target. However, targeting survivin is still challenge and small molecule inhibitors failed in clinical trials. It's very important to understand how survivin contributes to tumor development. In this study, we investigated the role of survivin in ovarian cancer using ovarian cancer cell lines in vitro and mouse models in vivo and examined how survivin contributes to ovarian primary ovarian tumor growth and metastasis by examining epithelial to mesenchymal transition (EMT). Methods: To define the role of survivin in EMT in ovarian cancer cells, we established survivin knockout cell lines using lentiviral CRISPR/Cas9 nickase and pharmacologically inhibited survivin with a novel inhibitor MX106. We examined EMT markers, migration and invasion assays in survivin disrupted ovarian cancer cells using Transwell plates. We also assessed primary ovarian tumor growth and metastasis in an orthotopic ovarian cancer mouse models through intrabursal injecting survivin KO cell line and also treatment using MX106. Findings: We found that disruption of survivin expression inhibited EMT by attenuating the TGFβ pathway in ovarian cancer cells. Cell proliferation, migration, and invasion were significantly inhibited in survivin knockout or MX106 treatment in SKOV3 and OVCAR3 cell lines compared to control cells. Inhibition of survivin sensitized cell responses to paclitaxel treatment and overcame chemoresistance in vitro. Lentiviral CRISPR/Cas9 mediated survivin knockout or MX106 treatment efficiently inhibited primary ovarian tumor growth and metastasis in orthotopic ovarian cancer mouse models. Conclusions: Our data demonstrate that inhibition of survivin using either genetic knockout or a novel inhibitor MX106 suppresses primary ovarian tumor growth and metastasis by attenuating TGFβ pathway. MX106, as a novel survivin inhibitor effectively overcame chemoresistance compared to commercial YM155, which provides a novel approach for ovarian cancer therapy. Citation Format: Junming Yue. Genetic and pharmacological disruption of survivin suppressed primary and metastatic tumor growth by attenuating TGFB pathway in ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4184.

Specific targeting of ovarian tumor-associated macrophages by large, anionic nanoparticles

Immunotherapy is emerging as one of the most effective methods for treating many cancers. However, immunotherapy can still introduce significant off-target toxicity, and methods are sought to enable targeted immunotherapy at tumor sites. Here, we show that relatively large (>100-nm) anionic nanoparticles administered intraperitoneally (i.p.) selectively accumulate in tumor-associated macrophages (TAMs). In a mouse model of metastatic ovarian cancer, fluorescently labeled silica, poly(lactic-co-glycolic acid), and polystyrene nanoparticles administered i.p. were all found to selectively accumulate in TAMs. Quantifying silica particle uptake indicated that >80% of the injected dose was in TAMs. Particles that were smaller than 100 nm or cationic or administered intravenously (i.v.) showed no TAM targeting. Moreover, this phenomenon is likely to occur in humans because when freshly excised human surgical samples were treated with the fluorescent silica nanoparticles no interaction with healthy tissue was seen but selective uptake by TAMs was seen in 13 different patient samples. Ovarian cancer is a deadly disease that afflicts ∼22,000 women per year in the United States, and the presence of immunosuppressive TAMs at tumors is correlated with decreased survival. The ability to selectively target TAMs opens the door to targeted immunotherapy for ovarian cancer.

Dual targeting of GSK3B and HDACs reduces tumor growth and improves survival in an ovarian cancer mouse model

ObjectiveTo investigate the anti-tumor effect of a newly-developed dual inhibitor (APCS-540) of glycogen synthase kinase 3 beta (GSK3B) and histone deacetylases (HDACs) in ovarian cancer cells. MethodsThe effects of APCS-540 on cancer cell proliferation, migration, invasion and cancer stemness were investigated in vitro in human (KURAMOCHI, OVCA420, OVSAHO) and mouse (BR-Luc, ID8, MOSE-HRas-Myc) ovarian cancer cells. Cisplatin-sensitive (A2780) and cisplatin-resistant (A2780cis) cell lines were used to evaluate APCS-540's effect on chemoresistance. The immunocompetent syngeneic mouse model BR-Luc was used to test the effect of APCS-540 on ovarian cancer progression and survival. ResultsAPCS-540 showed significant anti-tumor effects in vitro in both human and mouse ovarian cancer cells. Importantly, APCS-540 demonstrated marked cytotoxicity against cisplatin-resistant cancer cells and reversed cisplatin-resistance when used in combination with platinum. APCS-540 significantly decreased cancer cell invasion. A significant 66% increase in survival was observed in mice treated with APCS-540 compared to control mice. ConclusionDual inhibition of GSK3B and HDACs via APCS-540 showed potent anti-tumor activity in vitro and in vivo, suggesting that APCS-540 may provide a novel treatment option for ovarian cancer, including the platinum-resistant disease.