TRX-E-002-1 Induces c-Jun-Dependent Apoptosis in Ovarian Cancer Stem Cells and Prevents Recurrence In Vivo

Immune Modulation of Innate and Adaptive Responses Restores Immune Surveillance and Establishes Antitumor Immunologic Memory

Current immunotherapies have proven effective in strengthening antitumor immune responses, but constant opposing signals from tumor cells and the surrounding microenvironment eventually lead to immune escape. We hypothesized that in situ release of antigens and regulation of both the innate and adaptive arms of the immune system would provide a robust and long-term antitumor effect by creating immunologic memory against tumors. To achieve this, we developed CARG-2020, a genetically modified virus-like vesicle (VLV) that is a self-amplifying RNA with oncolytic capacity and encodes immune regulatory genes. CARG-2020 carries three immune modulators: (i) the pleiotropic antitumor cytokine IL12, in which the subunits (p35 and p40) are tethered together; (ii) the extracellular domain (ECD) of the protumor IL17RA, which serves as a dominant-negative antagonist; and (iii) a shRNA targeting PD-L1. Using a mouse model of ovarian cancer, we demonstrated the oncolytic effect and immune-modulatory capacities of CARG-2020. By enhancing IL12 and blocking IL17 and PD-L1, CARG-2020 successfully reactivated immune surveillance by promoting M1, instead of M2, macrophage differentiation, inhibiting MDSC expansion and establishing a potent CD8+ T cell-mediated antitumoral response. Furthermore, we demonstrated that this therapeutic approach provided tumor-specific and long-term protection against the establishment of new tumors. Our results provide a rationale for the further development of this platform as a therapeutic modality for ovarian cancer patients to enhance antitumor responses and prevent a recurrence.

Microtubule-Targeting Combined with HDAC Inhibition Is a Novel Therapeutic Strategy for Diffuse Intrinsic Pontine Gliomas

Diffuse intrinsic pontine gliomas (DIPG) are an incurable childhood brain cancer for which novel treatments are needed. DIPGs are characterized by a mutation in the H3 histone (H3K27M), resulting in loss of H3K27 methylation and global gene dysregulation. TRX-E-009-1 is a novel anticancer agent with preclinical activity demonstrated against a range of cancers. We examined the antitumor activity of TRX-E-009-1 against DIPG neurosphere cultures and observed tumor-specific activity with IC50s ranging from 20 to 100 nmol/L, whereas no activity was observed against normal human astrocyte cells. TRX-E-009-1 exerted its anti-proliferative effect through the induction of apoptotic pathways, with marked increases in cleaved caspase 3 and cleaved PARP levels, while also restoring histone H3K27me3 methylation. Co-administration of TRX-E-009-1 and the histone deacetylase (HDAC) inhibitor SAHA extended survival in DIPG orthotopic animal models. This antitumor effect was further enhanced with irradiation. Our findings indicate that TRX-E-009-1, combined with HDAC inhibition, represents a novel, potent therapy for children with DIPG.

A Novel Role of Connective Tissue Growth Factor in the Regulation of the Epithelial Phenotype

BACKGROUND

Epithelial-mesenchymal transition (EMT) is a biological process where epithelial cells lose their adhesive properties and gain invasive, metastatic, and mesenchymal properties. Maintaining the balance between the epithelial and mesenchymal stage is essential for tissue homeostasis. Many of the genes promoting mesenchymal transformation have been identified; however, our understanding of the genes responsible for maintaining the epithelial phenotype is limited. Our objective was to identify the genes responsible for maintaining the epithelial phenotype and inhibiting EMT.

METHODS

RNA seq was performed using an vitro model of EMT. CTGF expression was determined via qPCR and Western blot analysis. The knockout of CTGF was completed using the CTGF sgRNA CRISPR/CAS9. The tumorigenic potential was determined using NCG mice.

RESULTS

The knockout of CTGF in epithelial ovarian cancer cells leads to the acquisition of functional characteristics associated with the mesenchymal phenotype such as anoikis resistance, cytoskeleton remodeling, increased cell stiffness, and the acquisition of invasion and tumorigenic capacity.

CONCLUSIONS

We identified CTGF is an important regulator of the epithelial phenotype, and its loss is associated with the early cellular modifications required for EMT. We describe a novel role for CTGF, regulating cytoskeleton and the extracellular matrix interactions necessary for the conservation of epithelial structure and function. These findings provide a new window into understanding the early stages of mesenchymal transformation.

Immune modulation of innate and adaptive responses restores immune surveillance and establishes anti-tumor immunological memory

Current immunotherapies have proven effective in strengthening anti-tumor immune responses but constant opposing signals from tumor cells and surrounding microenvironment eventually lead to immune escape. We hypothesize that in situ release of antigens and regulation of both the innate and adaptive arms of the immune system will provide a robust and long-term anti-tumor effect by creating immunological memory against the tumor. To achieve this, we developed CARG-2020, a virus-like-vesicle (VLV). It is a genetically modified and self-amplifying RNA with oncolytic capacity and encodes immune regulatory genes. CARG-2020 carries three transgenes: 1 ) the pleiotropic antitumor cytokine IL-12 in which the subunits (p35 and p40) are tethered together; 2) the extracellular domain (ECD) of the pro- tumor IL-17RA, which can serve as a dominant negative antagonist; and 3) shRNA for PD-L1. Using a mouse model of ovarian cancer, we demonstrate the oncolytic effect and immune modulatory capacities of CARG-2020. By enhancing IL-12 and blocking IL-17 and PD-L1, CARG-2020 successfully reactivates immune surveillance by promoting M1 instead of M2 macrophage differentiation, inhibiting MDSC expansion, and establishing a potent CD8+ T cell mediated anti-tumoral response. Furthermore, we demonstrate that this therapeutic approach provides tumor-specific and long-term protection preventing the establishment of new tumors. Our results provide rationale for the further development of this platform as a therapeutic modality for ovarian cancer patients to enhance the anti-tumor response and to prevent recurrence.

Generation of Stable Epithelial-Mesenchymal Hybrid Cancer Cells with Tumorigenic Potential

PURPOSE

Cancer progression, invasiveness, and metastatic potential have been associated with the activation of the cellular development program known as epithelial-to-mesenchymal transition (EMT). This process is known to yield not only mesenchymal cells, but instead an array of cells with different degrees of epithelial and mesenchymal phenotypes with high plasticity, usually referred to as E/M hybrid cells. The characteristics of E/M hybrid cells, their importance in tumor progression, and the key regulators in the tumor microenvironment that support this phenotype are still poorly understood.

METHODS

In this study, we established an in vitro model of EMT and characterized the different stages of differentiation, allowing us to identify the main genomic signature associated with the E/M hybrid state.

RESULTS

We report that once the cells enter the E/M hybrid state, they acquire stable anoikis resistance, invasive capacity, and tumorigenic potential. We identified the hepatocyte growth factor (HGF)/c-MET pathway as a major driver that pushes cells in the E/M hybrid state.

CONCLUSIONS

Herein, we provide a detailed characterization of the signaling pathway(s) promoting and the genes associated with the E/M hybrid state.

MNRR1 is a driver of ovarian cancer progression

Cancer progression requires the acquisition of mechanisms that support proliferative potential and metastatic capacity. MNRR1 (also CHCHD2, PARK22, AAG10) is a bi-organellar protein that in the mitochondria can bind to Bcl-xL to enhance its anti-apoptotic function, or to respiratory chain complex IV (COX IV) to increase mitochondrial respiration. In the nucleus, it can act as a transcription factor and promote the expression of genes involved in mitochondrial biogenesis, migration, and cellular stress response. Given that MNRR1 can regulate both apoptosis and mitochondrial respiration, as well as migration, we hypothesize that it can modulate metastatic spread. Using ovarian cancer models, we show heterogeneous protein expression levels of MNRR1 across samples tested and cell-dependent control of its stability and binding partners. In addition to its anti-apoptotic and bioenergetic functions, MNRR1 is both necessary and sufficient for a focal adhesion and ECM repertoire that can support spheroid formation. Its ectopic expression is sufficient to induce the adhesive glycoprotein THBS4 and the type 1 collagen, COL1A1. Conversely, its deletion leads to significant downregulation of these genes. Furthermore, loss of MNRR1 leads to delay in tumor growth, curtailed carcinomatosis, and improved survival in a syngeneic ovarian cancer mouse model. These results suggest targeting MNRR1 may improve survival in ovarian cancer patients.

Synthesis and evaluation of benzoylbenzofurans and isoflavone derivatives as sirtuin 1 inhibitors with antiproliferative effects on cancer cells

Isoflavone derivatives were prepared from benzoylbenzofuran precursors. The synthesized compounds were analyzed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, as well as high-resolution mass spectrometry (HRMS) to confirm their structures. The benzoylbenzofuran and isoflavone analogues were evaluated for inhibition of sirtuin 1 (SIRT1) and cell proliferation in MDA-MB-231 triple-negative breast cancer (TNBC) cells. Several isoflavone and benzoylbenzofuran derivatives exhibited potent antiproliferative effects against the MDA-MB-231 cancer cell line. Most of the isoflavone derivatives attenuated SIRT1 activity to below 50%. The most active compounds were the isoflavone quinones 38, 39, and 40, at IC₅₀ values of 5.58 ± 0.373, 1.62 ± 0.0720, and 7.24 ± 0.823 μM, respectively. Importantly, the most active compound, 6-methoxy-4',6'-dimethylisoflavone-2',5'-quinone (39) displayed SIRT1 inhibitory activity comparable to that of the reference compound, suramin. The in silico docking simulations in the active site of SIRT1 further substantiated the experimental results and explored the binding orientations of potent compounds in the active site of the target.

A Network Pharmacology Study to Uncover the Mechanism of FDY003 for Ovarian Cancer Treatment

Ovarian cancer (OC) is one of the deadliest gynecological tumors responsible for 0.21 million deaths per year worldwide. Despite the increasing interest in the use of herbal drugs for cancer treatment, their pharmacological effects in OC treatment are not understood from a systems perspective. Using network pharmacology, we determined the anti-OC potential of FDY003 from a comprehensive systems view. We observed that FDY003 suppressed the viability of human OC cells and further chemosensitized them to cytotoxic chemotherapy. Through network pharmacological and pharmacokinetic approaches, we identified 16 active ingredients in FDY003 and their 108 targets associated with OC mechanisms. Functional enrichment investigation revealed that the targets may coordinate diverse cellular behaviors of OC cells, including their growth, proliferation, survival, death, and cell cycle regulation. Furthermore, the FDY003 targets are important constituents of diverse signaling pathways implicated in OC mechanisms (eg, phosphoinositide 3-kinase [PI3K]-Akt, mitogen-activated protein kinase [MAPK], focal adhesion, hypoxia-inducible factor [HIF]-1, estrogen, tumor necrosis factor [TNF], erythroblastic leukemia viral oncogene homolog [ErbB], Janus kinase [JAK]-signal transducer and activator of transcription [STAT], and p53 signaling). In summary, our data present a comprehensive understanding of the anti-OC effects and mechanisms of action of FDY003.

Maximum Tolerated Dose and Anti-Tumor Activity of Intraperitoneal Cantrixil (TRX-E-002-1) in Patients with Persistent or Recurrent Ovarian Cancer, Fallopian Tube Cancer, or Primary Peritoneal Cancer: Phase I Study Results

Survival outcomes in ovarian cancer are poor. The aims of this Phase I progressive design study (NCT02903771) were to evaluate the maximum tolerated dose (MTD), tolerability, and antitumor activity of Cantrixil-a novel third-generation benzopyran molecule-in patients (n = 25) with advanced, recurrent/persistent epithelial ovarian, primary peritoneal, or fallopian tube cancer. All had completed ≥ 2 prior regimens; 3 (12%) had platinum-refractory disease, and 17 (68%) had platinum-resistant disease. Following intraperitoneal (IP) port placement, patients received weekly IP Cantrixil in 3-week cycles as monotherapy (Cycles 1-2), and then in combination with intravenous (IV) chemotherapy (Cycles 3-8). Part A (dose escalation) enrolled 11 patients in 6 dose-level cohorts. An MTD of 5 mg/kg was established with dose-limiting toxicity of ileus. Most treatment-related adverse events were gastrointestinal. Across Parts A and B (dose expansion), 16 (64%) patients received ≥ 1 3-week Cantrixil cycle, and had ≥ 1 post-baseline efficacy measurement available. The results show promising anti-tumor activity in monotherapy (stable disease rate of 56%) and in combination with IV chemotherapy (objective response rate of 19%, disease control rate of 56%, and median progression-free survival of 13.1 weeks). The molecular target and mechanism of action of Cantrixil are yet to be confirmed. Preliminary analysis of stem cell markers suggests that IP Cantrixil might induce ovarian cancer stem cell death and sensitize cells to standard chemotherapy, warranting further evaluation.

JNK signaling as a target for anticancer therapy

The JNKs are members of mitogen-activated protein kinases (MAPK) which regulate many physiological processes including inflammatory responses, macrophages, cell proliferation, differentiation, survival, and death. It is increasingly clear that the continuous activation of JNKs has a role in cancer development and progression. Therefore, JNKs represent attractive oncogenic targets for cancer therapy using small molecule kinase inhibitors. Studies showed that the two major JNK proteins JNK1 and JNK2 have opposite functions in different types of cancers, which need more specification in the design of JNK inhibitors. Some of ATP- competitive and ATP non-competitive inhibitors have been developed and widely used in vitro, but this type of inhibitors lack selectivity and inhibits phosphorylation of all JNK substrates and may lead to cellular toxicity. In this review, we summarized and discussed the strategies of JNK binding inhibitors and the role of JNK signaling in the pathogenesis of different solid and hematological malignancies.

Lassa-VSV chimeric virus targets and destroys human and mouse ovarian cancer by direct oncolytic action and by initiating an anti-tumor response

Ovarian cancer is the third most common female cancer, with poor survival in later stages of metastatic spread. We test a chimeric virus consisting of genes from Lassa and vesicular stomatitis viruses, LASV-VSV; the native VSV glycoprotein is replaced by the Lassa glycoprotein, greatly reducing neurotropism. Human ovarian cancer cells in immunocompromised nude mice were lethal in controls. Chemotherapeutic paclitaxel and cisplatin showed modest cancer inhibition and survival extension. In contrast, a single intraperitoneal injection of LASV-VSV selectively infected and killed ovarian cancer cells, generating long-term survival. Mice with human ovarian cancer cells in brain showed rapid deterioration; LASV-VSV microinjection into brain blocked cancer growth, and generated long-term survival. Treatment of immunocompetent mice with infected mouse ovarian cancer cells blocked growth of non-infected ovarian cancer cells peritoneally and in brain. These results suggest LASV-VSV is a viable candidate for further study and may be of use in the treatment of ovarian cancer.

Transimmunization restores immune surveillance and prevents recurrence in a syngeneic mouse model of ovarian cancer

Ovarian cancer accounts for most deaths from gynecologic malignancies. Although more than 80% of patients respond to first-line standard of care, most of these responders present with recurrence and eventually succumb to carcinomatosis and chemotherapy-resistant disease. To improve patient survival, new modalities must, therefore, target or prevent recurrent disease. Here we describe for the first time a novel syngeneic mouse model of recurrent high-grade serous ovarian cancer (HGSOC), which allows immunotherapeutic interventions in a time course relevant to human carcinomatosis and disease course. Using this model, we demonstrate the efficacy of Transimmunization (TI), a dendritic cell (DC) vaccination strategy that uses autologous and physiologically derived DC loaded with autologous whole tumor antigens. TI has been proven successful in the treatment of human cutaneous T cell lymphoma and we report for the first time its in vivo efficacy against an intra-peritoneal solid tumor. Given as a single therapy, TI is able to elicit an effective anti-tumor immune response and inhibit immune-suppressive crosstalks with sufficient power to curtail tumor progression and establishment of carcinomatosis and recurrent disease. Specifically, TI is able to inhibit the expansion of tumor-associated macrophages as well as myeloid-derived suppressive cells consequently restoring T cell immune-surveillance. These results demonstrate the possible value of TI in the management of ovarian cancer and other intra-peritoneal tumors.

CBX7 binds the E-box to inhibit TWIST-1 function and inhibit tumorigenicity and metastatic potential

Deaths from ovarian cancer usually occur when patients succumb to overwhelmingly numerous and widespread micrometastasis. Whereas epithelial-mesenchymal transition is required for epithelial ovarian cancer cells to acquire metastatic potential, the cellular phenotype at secondary sites and the mechanisms required for the establishment of metastatic tumors are not fully determined. Using in vitro and in vivo models we show that secondary epithelial ovarian cancer cells (sEOC) do not fully reacquire the molecular signature of the primary epithelial ovarian cancer cells from which they are derived. Despite displaying an epithelial morphology, sEOC maintains a high expression of the mesenchymal effector, TWIST-1. TWIST-1 is however transcriptionally nonfunctional in these cells as it is precluded from binding its E-box by the PcG protein, CBX7. Deletion of CBX7 in sEOC was sufficient to reactivate TWIST-1-induced transcription, prompt mesenchymal transformation, and enhanced tumorigenicity in vivo. This regulation allows secondary tumors to achieve an epithelial morphology while conferring the advantage of prompt reversal to a mesenchymal phenotype upon perturbation of CBX7. We also describe a subclassification of ovarian tumors based on CBX7 and TWIST-1 expression, which predicts clinical outcomes and patient prognosis.

Mechanism of action of the third generation benzopyrans and evaluation of their broad anti-cancer activity in vitro and in vivo

Successive rounds of chemical modification in three generations of benzopyran molecules have shown to select for different mechanisms of actions and progressive increases in anti-cancer activity. In this study, we investigated the mechanism of action of the third-generation benzopyran compounds, TRX-E-002-1 and TRX-E-009-1. High-content screening of a panel of 240 cancer cell lines treated with TRX-E-009-1 demonstrated it has broad anti-cancer potential. Within this screen, melanoma cell lines showed a range of sensitivities and subsequently a second independent panel of 21 melanoma 3D spheroid lines were assessed for their responses to both TRX-E-002-1 and TRX-E-009-1 compounds. Time-lapse microscopy illustrated both of these compounds caused mitotic delays in treated cells, resulting in either mitotic slippage or apoptosis. This finding along with immunostaining, in vitro polymerization assays, and animal experiments in both athymic and immunocompetent mice, demonstrates that these third-generation benzopyran compounds are potent tubulin polymerization inhibitors in vitro and in vivo, and this is the molecular basis of their anti-cancer activity in melanoma. These findings indicate these BP compounds may offer a novel anti-microtubule strategy for cancer intervention and provides the basis for further investigation into biomarkers of clinical sensitivity.

Adipocyte microenvironment promotes Bclxl expression and confers chemoresistance in ovarian cancer cells

Resistance to mitochondria-initiated apoptosis is a hallmark of chemoresistant cancer stem cells including CD44+/MyD88+ epithelial ovarian cancer (EOC) stem cells. This is controlled by members of the Bcl₂ family of proteins, which function as rheostats of mitochondrial stability. We observed a differential expression profile of Bcl₂ family members comparing the chemoresistant EOC stem cells and the chemosensitive CD44-/MyD88- EOC cells. Chemoresistant EOC stem cells surprisingly express higher levels of the pro-apoptotic members Bak and Bax compared to the chemosensitive EOC cells. In addition, whereas chemosensitive EOC cells preferentially express Bcl₂, chemoresistant EOC stem cells preferentially express Bcl_xl. In the EOC stem cells, 40% knock-down of Bcl_xl expression was sufficient to induce the full activation of caspases and this can be reversed by concurrent knock-down of Puma. More importantly, we demonstrate that Bcl_xl expression levels in EOC cells is dynamic and can be regulated by microenvironments that are enriched with the pro-inflammatory cytokine IL-6 such as the cancer stem cell and adipocyte niches. Adipocyte-induced upregulation of Bcl_xl correlated with acquisition of chemoresistance and thus demonstrates how a specific microenvironment can regulate the expression of apoptotic proteins and confer chemoresistance.

Identification of the anticancer effects of a novel proteasome inhibitor, ixazomib, on colorectal cancer using a combined method of microarray and bioinformatics analysis

Purpose

The study aimed to explore the anticancer effects of a novel proteasome inhibitor, ixazomib, on colorectal cancer (CRC) using a combined method of microarray and bioinformatics analysis.

Materials and methods

Cell proliferation was tested by Cell Counting Kit-8 (CCK-8) assay for SW620 cells treated with different concentrations of ixazomib and different treatment times. The microarray analysis was conducted for six samples, including three samples of SW620 cells untreated with ixazomib and three samples of SW620 cells treated with ixazomib. The differentially expressed genes (DEGs) between untreated and treated samples were identified by the Linear Models for Microarray data (LIMMA) package in R language. The Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed for the DEGs using the Database for Annotation, Visualization and Integrated Discovery (DAVID) and KEGG Orthology-Based Annotation System (KOBAS) online tool. The protein–protein interaction (PPI) network was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database, and module analysis was performed for the PPI network.

Results

Ixazomib could inhibit the proliferation of SW620 cells in a dose-dependent and time-dependent manner. A total of 743 DEGs, including 203 upregulated DEGs such as HSPA6 and 540 downregulated DEGs such as APCDD1, were identified. Eighty-three GO terms were enriched for DEGs, which were mainly related to protein folding, apoptotic process, transcription factor activity, and proteasome. Thirty-seven KEGG pathways were perturbed, including pathway of apoptosis and cell cycle. Forty-six hub genes, such as TP53, JUN, and ITGA2, were screened out, and three modules with important functions were mined from the PPI network.

Conclusion

The novel proteasome inhibitor ixazomib significantly inhibited the proliferation of human CRC SW620 cells. It exerted anticancer effects through targeting the expression of DEGs, such as HSPA6, APCDD1, TP53, and JUN, and affecting the signaling pathways including apoptosis and cell cycle pathway, which demonstrated the promising potential of ixazomib for CRC therapy.

Novel approach for the detection of intraperitoneal micrometastasis using an ovarian cancer mouse model

Patients with epithelial ovarian cancer have the best overall survival when maximal surgical effort is accomplished. However, despite numerous technological advances, surgery still relies primarily on white-light reflectance and the surgeon’s vision. As such, micrometastases are usually missed and most patients clinically classified as a complete responder eventually recur and succumb to the disease. Our objective is to develop optical enhancers which can aid in the visualization of ovarian cancer micrometastasis. To this end we developed a nanoparticle (NP) platform, which is specifically targeted to the tumor microenvironment. Targeting is achieved by coating FDA-approved PLGA-PEG NP with the peptide sequence RGD, which binds with high affinity to αVβ3 integrins present in both the tumor-associated neovasculature and on the surface of ovarian cancer cells. Administration of the NP platform carrying fluorescent dyes to mice bearing intraperitoneal ovarian cancer allowed visualization of tumor-associated vasculature and its contrast against normal blood vessels. More importantly, we demonstrate the visualization of intraperitoneal ovarian cancer micrometastasis as small as 100 μm with optimal resolution. Finally, we demonstrate that the fluorescent dye cargo was able to penetrate intra-tumorally. Such modality could be used to allow microscopic surgical debulking to assure maximal surgical effort.

Pharmacology and toxicology of the novel investigational agent Cantrixil (TRX-E-002-1)

PURPOSE

Recurrent, chemo-resistant ovarian cancer is thought to be due to a subgroup of slow-growing, drug-resistant cancer cells with stem-like properties and a high capacity for tumour repair. Cantrixil targets this sub-population of cells and is being developed as an intraperitoneal therapy to be used as first-line therapy in combination with carboplatin for epithelial ovarian cancer. The studies presented here justify further development.

METHODS

A GLP dog CV study using a 4 × 4 Latin Square Crossover study was conducted using telemetric ECG recordings from dogs post IP administration to assess for cardiac abnormalities. Mutagenic potential was assessed using the bacterial reverse mutation assay. Clastogenicity was assessed by determining micronuclei formation in the bone marrow of SPF Arc(S) Swiss mice dosed at clinical concentrations. TRX-E-002-1 toxicology was evaluated in GLP-compliant MTD and 28-day repeat-dose studies in rats and dogs.

RESULTS

In vitro TRX-E-002-1 has potent cytotoxic activity against human cancer cells including CD44+/MyD88+ ovarian cancer stem cells. TRX-E-002-1 increased phosphorylated c-Jun levels in these cancer cells resulting in caspase-mediated apoptosis. In vivo, Cantrixil was active in a model of disseminated ovarian cancer as a monotherapy and in combination with Cisplatin. Cantrixil was active as maintenance therapy in a model of drug-resistant, recurrent ovarian cancer and in an orthotopic model of pancreatic cancer.

CONCLUSIONS

In animals, this clinical formulation and route of administration of Cantrixil demonstrated acceptable activity, safety pharmacology, genotoxicity and toxicology profile and constituted a successful Investigational New Drug application to the US Food and Drug Administration.

TWIST1 drives cisplatin resistance and cell survival in an ovarian cancer model, via upregulation of GAS6, L1CAM, and Akt signalling

Epithelial ovarian cancer (EOC) is the most deadly gynaecologic malignancy due to late onset of symptoms and propensity towards drug resistance. Epithelial-mesenchymal transition (EMT) has been linked to the development of chemoresistance in other cancers, yet little is known regarding its role in EOC. In this study, we sought to determine the role of the transcription factor TWIST1, a master regulator of EMT, on cisplatin resistance in an EOC model. We created two Ovcar8-derived cell lines that differed only in their TWIST1 expression. TWIST1 expression led to increased tumour engraftment in mice, as well as cisplatin resistance in vitro. RNA sequencing analysis revealed that TWIST1 expression resulted in upregulation of GAS6 and L1CAM and downregulation of HMGA2. Knockdown studies of these genes demonstrated that loss of GAS6 or L1CAM sensitized cells to cisplatin, but that loss of HMGA2 did not give rise to chemoresistance. TWIST1, in part via GAS6 and L1CAM, led to higher expression and activation of Akt upon cisplatin treatment, and inhibition of Akt activation sensitized cells to cisplatin. These results suggest TWIST1- and EMT-driven increase in Akt activation, and thus tumour cell proliferation, as a potential mechanism of drug resistance in EOC.