NCAPG upregulation mediated by four microRNAs combined with activation of the p53 signaling pathway is a predictor of poor prognosis in patients with breast cancer

The role of non-SMC condensin I complex subunit G (NCAPG) in breast cancer remains unclear. The present study used online databases, reverse transcription-quantitative PCR, flow cytometry and western blotting to determine the expression levels, prognosis and potential molecular mechanisms underlying the role of NCAPG in breast cancer. The association between NCAPG expression and several different clinicopathological parameters in patients with breast cancer was determined, and the results revealed that NCAPG expression was negatively associated with estrogen receptor and progesterone receptor positive status, but was positively associated with HER2 positive status, Nottingham Prognostic Index score and Scarff-Bloom-Richardson grade status. Furthermore, upregulated expression levels of NCAPG resulted in a poor prognosis in patients with breast cancer. A total of 27 microRNAs (miRNAs/miRs) were predicted to target NCAPG, among which four miRNAs (miR-101-3p, miR-195-5p, miR-214-3p and miR-944) were predicted to most likely regulate NCAPG expression in breast cancer. A total of 261 co-expressed genes of NCAPG were identified, including cell division cyclin 25 homolog C (CDC25C), and pathway enrichment analysis indicated that these co-expressed genes were significantly enriched in the p53 signaling pathway. CDC25C expression was downregulated in breast cancer and was associated with a poor prognosis. These findings suggested that upregulated NCAPG expression may be a prognostic biomarker of breast cancer.

Regulation of NCAPG by miR-99a-3p (passenger strand) inhibits cancer cell aggressiveness and is involved in CRPC

Effective treatments for patients with castration-resistant prostate cancer (CRPC) have not yet been established. Novel approaches for identification of putative therapeutic targets for CRPC are needed. Analyses of RNA sequencing of microRNA (miRNA) expression revealed that miR-99a-3p (passenger strand) is significantly downregulated in several types of cancers. Here, we aimed to identify novel miR-99a-3p regulatory networks and therapeutic targets for CRPC. Ectopic expression of miR-99a-3p significantly inhibited cancer cell proliferation, migration, and invasion in PCa cells. Non-SMC condensin I complex subunit G (NCAPG) was a direct target of miR-99a-3p in PCa cells. Overexpression of NCAPG was detected in CRPC clinical specimens and was significantly associated with shorter disease-free survival and advanced clinical stage. Knockdown of NCAPG inhibited cancer cell aggressiveness. The passenger strand miR-99a-3p acted as an antitumor miRNA in naïve PCa and CRPC. NCAPG was regulated by miR-99a-3p, and its overexpression was involved in CRPC pathogenesis. Involvement of passenger strand of miRNA in cancer pathogenesis is novel concept, and identification of antitumor miRNA regulatory networks in CRPC might be provided novel prognostic markers and therapeutic targets for this disease.