Xiaoli Liu

ITGA7 loss drives the differentiation of adipose‐derived mesenchymal stem cells to cancer‐associated fibroblasts

AbstractCancer‐associated fibroblasts (CAFs) represent a major cellular component of the tumor (pre‐)metastatic niche and play an essential role in omental dissemination of ovarian cancer. The omentum is rich in adipose, and adipose‐derived mesenchymal stem cells (ADSCs) have been identified as a source of CAFs. However, the molecular events driving the phenotype shift of ADSCs remain largely unexplored. In this research, we focus on integrins, transmembrane receptors that have been widely involved in cellular plasticity. We found that integrin α7 (ITGA7) was the only member of the integrin family that positively correlated with both overall survival and progression‐free survival in ovarian cancer through GEPIA2. The immunohistochemistry signal of ITGA7 was apparent in the tumor stroma, and a lower omental ITGA7 level was associated with metastasis. Primary ADSCs were isolated from the omentum of patients with ovarian cancer and identified by cellular morphology, biomarkers, and multilineage differentiation. The conditional medium of ovarian cancer cells induced ITGA7 expression decrease and phenotypic changes in ADSCs. Downregulation of ITGA7 in primary omental ADSCs led to decrease in stemness properties and emerge of characteristic morphology and biomarkers of CAFs. Moreover, the conditioned medium of ADSCs with ITGA7 depletion exhibited enhanced abilities to improve the migration and invasion of ovarian cancer cells in vitro. Overall, these findings indicate that loss of ITGA7 may induce the differentiation of ADSCs to CAFs that contribute to a tumor‐supportive niche.

Ubiquitin Ligase TRIM22 Inhibits Ovarian Cancer Malignancy via TCF4 Degradation

Abstract Ovarian cancer is one of the most common malignancies in women. Tripartite motif-containing protein 22 (TRIM22) plays an important role in the initiation and progression of malignant tumors. Similarly, the transcription factor 4 (TCF4) is an essential factor involved in the initiation and progression of many tumors. However, it is still unclear whether TRIM22 can affect TCF4 in ovarian cancer. Therefore, this study aims to investigate the mechanism related to TRIM22 and TCF4 in ovarian cancer. TRIM22 protein and mRNA levels were analyzed in samples from clinical and cell lines. The effects of TRIM22 knockdown and overexpression on cell proliferation, colony formation, migration, invasion, and related biomarkers were evaluated. In addition, the role of ubiquitination-mediated degradation of TCF4 was investigated by qRT-PCR and Western blotting. The association between TRIM22 and TCF4 was evaluated by Western blotting, coimmunoprecipitation, proliferation, colony formation, invasion, migration, and related biomarkers. The results showed that the expression of TRIM22 was minimal in ovarian cancer tissues. Furthermore, upregulation of TRIM22 significantly inhibited ovarian cancer cell proliferation, colony formation, migration, and invasion. In addition, TRIM22 was observed to regulate the degradation of TCF4 through the ubiquitination pathway. TCF4 can reverse the effects of TRIM22 on proliferation, colony formation, migration, and invasion in ovarian cancer cells. TRIM22-mediated ubiquitination of TCF4 at K48 is facilitated by the RING domain. Implications: In conclusion, ubiquitination of TCF4 protein in ovarian cancer is regulated by TRIM22, which has the potential to limit the proliferation, migration, and invasion of ovarian cancer.