Background: Bladder cancer (BC) is a malignant tumor that begins in the cells of the bladder, characterized by poor cell differentiation and strong invasion capacity, with a high incidence rate. Identifying key molecules that enhance BC cells' cisplatin sensitivity can help improve the clinical efficacy of BC treatment. Hence, this study aimed to determine the expression level of long non-coding RNA (lncRNA) ADAM Metallopeptidase with Thrombospondin Type 1 Motif 9 Antisense RNA 1 (ADAMTS9-AS1) in BC and explore its related mechanism underlying the amplification of cisplatin sensitivity.
Methods: Cancer tissues and para-cancerous tissues of 10 BC patients treated in The 908th Hospital of Joint Logistic Support Force of PLA were collected retrospectively and analyzed for the expression of the lncRNA ADAMTS9-AS1 and fused in sarcoma (FUS) in this tissue. Normal bladder epithelial cell line SV-HUC1, and BC cell lines such as T24, J82, 5637, KU-19-19, and EJ were cultured for in vitro experimentation. Then, the expression levels of ADAMTS9-AS1, FUS mRNA, and FUS protein were detected by means of reverse-transcription quantitative polymerase chain reaction (RT-qPCR), Western blotting, and immunohistochemistry. pcDNA3.1 vector, pcDNA3.1-ADAMTS9-AS1, or pcDNA3.1-ADAMTS9-AS1 and FUS overexpression plasmid was transfected into the cultured T24 and 5637 cells. A series of tests were performed to detect cell proliferation, migration capacity, apoptosis, and cisplatin half-effective concentration (IC50) values of BC cells using Cell Counting Kit-8 (CCK-8) assay, colony formation assay, wound healing assay, flow cytometry, and gradient cisplatin culturation.
Results: Compared with SV-HUC1 cell line and adjacent normal tissues, ADAMTS9-AS1 levels were significantly decreased in T24, J82, 5637, KU-19-19, EJ cell lines, and BC tissues, while FUS mRNA and protein expression levels were up-regulated (p < 0.05). After transfection with pcDNA3.1-ADAMTS9-AS1, the colony number, cell viability, wound healing ratio, and cisplatin IC50 value, were remarkably reduced (p < 0.05), but apoptosis ratio, cleaved-caspase3 and cleaved-poly-ADP-ribose polymerases (PARP) expressions were increased (p < 0.05). ADAMTS9-AS1 was found to directly target FUS, and overexpression of FUS reversed ADAMTS9-AS1 effects on BC cells.
Conclusions: ASAMTS9-AS1 can inhibit the proliferation and migration, and promote apoptosis and cisplatin sensitivity of BC cells through regulating FUS, thus providing a theoretical basis for ADAMTS9-AS1 as a potential therapeutic target in BC treatment.
Keywords: ADAMTS9-AS1; FUS; bladder cancer; cisplatin sensitivity.