Double Insurance for OC: miRNA-Mediated Platinum Resistance and Immune Escape

LINC01119 encapsulated by cancer-associated adipocytes-derived exosomes promotes M2 polarization of macrophages to induce immune escape in ovarian cancer in a 3D co-culture cell-based model

INTRODUCTION

In the present study, we sought to clarify the role of LINC01119 delivered by cancer-associated adipocytes (CAAs)-derived exosomes (CAA-Exo) and its mechanistic actions in ovarian cancer (OC).

MATERIALS AND METHODS

The expression of LINC01119 was determined in OC, and the relationship between LINC01119 expression and the prognosis of OC patients was analyzed. Besides, 3D co-culture cell models were constructed using green fluorescent protein-labeled OC cells and red fluorescent protein-labeled mature adipocytes. Mature adipocytes were co-cultured with OC cells to induce CAA. Macrophages treated with CAA-Exo were co-cultured with SKOV3 cells following ectopic expression and depletion experiments of LINC01119 and SOCS5 to detect M2 polarization of macrophages, PD-L1 level, proliferation of CD3+ T cells, and cytotoxicity of T cells to SKOV3 cells.

RESULTS

LINC01119 was elevated in the plasma Exo of OC patients, which was related to shorter overall survival in OC patients. LINC01119 expression was increased in CAA-Exo, which could upregulate SOCS5 in OC. Finally, CAA-Exo carrying LINC01119 induced M2 polarization of macrophages to promote immune escape in OC, as evidenced by inhibited CD3+ T cell proliferation, increased PD-L1 level, and attenuated T cell toxicity to SKOV3 cells.

CONCLUSION

In conclusion, the key findings of the current study demonstrated the promoting effects of CAA-Exo containing LINC01119 mediating SOCS5 on M2 polarization of macrophages and immune escape in OC.

Ovarian Cancer—Insights into Platinum Resistance and Overcoming It

Ovarian cancer is the most lethal gynecologic malignancy. Platinum-based chemotherapy is the backbone of treatment for ovarian cancer, and although the majority of patients initially have a platinum-sensitive disease, through multiple recurrences, they will acquire resistance. Platinum-resistant recurrent ovarian cancer has a poor prognosis and few treatment options with limited efficacy. Resistance to platinum compounds is a complex process involving multiple mechanisms pertaining not only to the tumoral cell but also to the tumoral microenvironment. In this review, we discuss the molecular mechanism involved in ovarian cancer cells’ resistance to platinum-based chemotherapy, focusing on the alteration of drug influx and efflux pathways, DNA repair, the dysregulation of epigenetic modulation, and the involvement of the tumoral microenvironment in the acquisition of the platinum-resistant phenotype. Furthermore, we review promising alternative treatment approaches that may improve these patients’ poor prognosis, discussing current strategies, novel combinations, and therapeutic agents.

Overexpression of transmembrane protein 102 implicates poor prognosis and chemoresistance in epithelial ovarian carcinoma patients

Most ovarian cancer patients experience disease recurrence and chemotherapeutic resistance, and the underlying mechanisms are unclear. Identifying relevant pathways could reveal new therapeutic targets. Here we examined expression of transmembrane protein 102 (TMEM102), a biomarker of prognosis and chemoresistance, in epithelial ovarian cancer (EOC), and assessed its role in inhibiting tumor cell apoptosis. We performed qRT-PCR to investigate the association of TMEM102 expression with clinical outcomes in 226 EOC patients. We also conducted in vitro studies to explore possible mechanisms through which TMEM102 may influence chemoresistance, including the effects of downregulating TMEM102 expression with small interfering RNA. Serous and high-grade carcinomas expressed significantly higher TMEM102 than normal ovarian tissues. TMEM102 was also overexpressed in patients with advanced-stage disease and chemoresistance. Reduction of TMEM102 expression by small interfering RNA induced ovarian cancer cell apoptosis after cytotoxic treatment. TMEM102 overexpression enhanced chemoresistance via upregulation of heat shock proteins 27, 60, and 70; and survivin, resulting in decreased cytochrome c in the mitochondria and decreased caspase 9 expression. Our results indicate that TMEM102 overexpression may promote chemoresistance via inhibition of a mitochondria-associated apoptotic pathway.

MiR-320b and miR-320d as Biomarkers to Predict and Participate in the Formation of Platinum Resistance in Ovarian Cancer Patients

Patients with ovarian cancer who receive platinum-based chemotherapy typically develop platinum resistance, which leads to tumor recurrence and mortality. Therefore, finding the underlying mechanisms and biomarkers is critical. A total of 51 platinum-resistant and 70 platinum-sensitive ovarian cancer patients were enrolled in this study. We examined the GSE131978 dataset in the National Center for Biotechnology Information (NCBI) Gene Expression Omnibus database for differentially expressed long non-coding RNAs and messenger RNAs (mRNAs) between platinum-resistant and platinum-sensitive patients and completed a microRNA chip analysis. After filtering by Pearson correlation analysis, the competitive endogenous RNA (ceRNA) networks were subsequently constructed. Then, the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology enrichment analyses about mRNAs in ceRNA networks were accomplished. More crucially, we demonstrated the differentially expressed microRNAs using quantitative real-time PCR and fluorescence in situ hybridization. The feasibility of microRNAs as biomarkers to predict platinum resistance and tumor recurrence was assessed using the receiver operating characteristic curve and survival analysis. MiR-320b and miR-320d exhibited high area under the curve values of 0.757 and 0.702, respectively. In our study, ceRNA networks including miR-320b and miR-320d probably provided novel insights for platinum resistance in ovarian cancer patients.

Interaction of Adenosine, Modified Using Carborane Clusters, with Ovarian Cancer Cells: A New Anticancer Approach against Chemoresistance

Platinum compounds remain the first-line drugs for the treatment of most lethal gynecological malignancies and ovarian cancers. Acquired platinum resistance remains a major challenge in gynecological oncology. Considering the unique physicochemical properties of the metallacarboranes modifier and the significant role of nucleoside derivatives as anticancer antimetabolites, we designed and synthesized a set of adenosine conjugates with metallacarboranes containing iron, cobalt, or chromium as semi-abiotic compounds that influence the cisplatin sensitivity of ovarian cancer cells. Adherent cultures of ovarian carcinoma cell lines and multicellular spheroids, ranging from sensitive to highly resistant including experimental cell lines "not responding" to platinum drugs were used. Iron-containing metallacarborane conjugates showed the best anticancer activity, especially against resistant cells. Compound modified at the C2' nucleoside position showed the best activity in resistant cancer cells and highly resistant cancer spheroids exposed to cisplatin, increasing cell cycle arrest, apoptosis or necrosis, and reactive oxygen species production. Moreover, it showed high cellular accumulation and did not induce cross-resistance to cisplatin, carboplatin, doxorubicin, paclitaxel, or gemcitabine in long-term cultures. The reference nido-carborane derivative (no metal ions) and unmodified nucleosides were not as effective. These findings indicate that metallacarborane modification of adenosine may sensitize ovarian cancer cells to cisplatin in combination treatment.