Jinhua Zhou

Targeting of Tumoral NAC1 Mitigates Myeloid-Derived Suppressor Cell–Mediated Immunosuppression and Potentiates Anti–PD-1 Therapy in Ovarian Cancer

Abstract Epithelial ovarian cancer is the most common type of ovarian cancer with a low rate of response to immunotherapy such as immune checkpoint blockade therapy. In this study, we report that nucleus accumbens–associated protein 1 (NAC1), a putative driver of epithelial ovarian cancer, has a critical role in immune evasion. We showed in murine ovarian cancer models that depleting or inhibiting tumoral NAC1 reduced the recruitment and immunosuppressive function of myeloid-derived suppressor cells (MDSC) in the tumor microenvironment, led to significant increases of cytotoxic tumor-infiltrating CD8+ T cells, and promoted antitumor immunity and suppressed tumor progression. We further showed that tumoral NAC1 directly enhanced the transcription of CXCL16 by binding to CXCR6, thereby promoting MDSC recruitment to the tumor. Moreover, lipid C20:1T produced by NAC1-expressing tumor cells fueled oxidative metabolism of MDSCs and promoted their immune-suppressive function. We also showed that NIC3, a small-molecule inhibitor of NAC1, was able to sensitize mice bearing NAC1-expressing ovarian tumors to anti–PD-1 therapy. Our study reveals a critical role for NAC1 in controlling tumor infiltration of MDSCs and in modulating the efficacy of immune checkpoint blockade therapy. Thus, targeting of NAC1 may be exploited to sensitize ovarian cancer to immunotherapy.

SORBS3-β suppresses lymph node metastasis in cervical cancer by promoting the ubiquitination of β-catenin

Cervical cancer (CC) is a prevalent gynecological malignancy, with lymph node metastasis (LNM) serving as a critical factor influencing patient prognosis. SORBS3, an adaptor protein with two known isoforms (α and β), has been implicated in tumor suppression, but the specific roles of its isoforms in CC metastasis remains unexplored. This study aimed to identify the functional isoform of SORBS3 driving LNM suppression and elucidate its mechanisms. Proteomic analysis of clinical CC tissues and metastatic lymph nodes revealed progressive downregulation of SORBS3. The mRNA and protein levels of SORBS3-α and SORBS3-β were subsequently examined in normal cervical epithelial and CC cell lines. Functional studies, including siRNA-mediated knockdown of SORBS3-α, lentiviral-mediated overexpression and knockdown of SORBS3-β, Transwell migration, lymphangiogenesis assays, and in vivo footpad xenograft models, were conducted to evaluate the role of SORBS3 isoforms in LNM. SORBS3 DNA methylation mechanisms were analyzed by MSP and Targeted Bisulfite sequencing. Mechanistic insights were derived from Co-IP, ubiquitination assays, RNA-seq, and LC-MS/MS. Knockdown of SORBS3-α had no effect on CC cell migration, invasion, or lymphangiogenesis. In contrast, SORBS3-β overexpression markedly suppressed CC cell invasion, lymphangiogenesis, and adhesion to lymphatic endothelial cells, whereas its knockdown significantly promoted these phenotypes. Promoter hypermethylation driven by DNMT-1 inhibited SORBS3 expression in CC. SORBS3- β directly binds to β-catenin and recruits UBA1 to enhance its ubiquitination and degradation, thereby inhibiting Wnt/β-catenin signaling. This inhibition reduced accumulation of β-catenin and downregulated the pro-lymphangiogenic gene VEGFC, ultimately suppressing lymphangiogenesis and LNM. In vivo, SORBS3-β overexpression attenuated lymphatic metastasis in nude mice, whereas its knockdown promoted metastasis. SORBS3-β is the major isoform of SORBS3 that inhibits lymphatic metastasis of cervical cancer by degrading β-catenin through UBA1-mediated ubiquitination, blocking Wnt/β-catenin signaling and downstream lymphangiogenesis pathways, thereby inhibiting lymphatic metastasis. Our findings elucidate key molecular mechanisms underlying cervical cancer lymph node metastasis, offering potential therapeutic targets.metastasis.

Guanosine monophosphate synthase upregulation mediates cervical cancer progression by inhibiting the apoptosis of cervical cancer cells via the Stat3/P53 pathway

Guanosine monophosphate synthase (GMPS) participates in chromatin and gene regulation in multiple types of organisms, and is highly expressed in a variety of human malignancies. The purpose of the present study was to explore the expression of GMPS and its role in cervical cancer (CC), and to provide ideas for improving the clinical efficacy of CC treatment. In the present study, immunohistochemistry, reverse transcription‑quantitative PCR analysis, Cell Counting Kit‑8 assay, 5‑ethynyl‑2'‑deoxyuridine assay, flow cytometry, western blotting and immunofluorescence assays were conducted to detect the expression of GMPS in normal cervical tissues, CC tissues, para‑cancerous tissues and CC cell lines. Moreover, the present study detected the effect of GMPS knockdown on CC cell proliferation, clonal formation ability, aging and apoptosis, as well as on the expression levels of apoptosis‑related proteins in tumor cells. The present results demonstrated that the expression level of GMPS in CC was significantly higher compared with that of adjacent tissues; the expression rate of GMPS in CC was 57.36%. GMPS expression was found to successively and gradually increase from that in normal cervical tissues, to that in cervical intraepithelial neoplasia and CC tissues. The abnormal expression of GMPS was positively associated with the degree of CC differentiation and the depth of early invasion. Small interfering (si)RNA knockdown of GMPS inhibited proliferation and colony formation, and promoted aging and apoptosis of CC cells. Furthermore, subcutaneous injection of GMPS‑knockdown tumor cells in nude mice resulted in a decrease in the proliferative ability of the tumor. The animal experimental results showed that the tumor growth rate of the short hairpin (sh)RNA‑GMPS group was significantly slower than that of the HeLa sh‑negative control group. It was identified that GMPS may inhibit CC cell senescence and apoptosis via the Stat3/P53 molecular pathway. Collectively, the present results suggested that GMPS may be a marker of unfavorable prognosis of CC, and it may also be a potential therapeutic target for CC.