S1. A. CCK-8 assay was used to detect the cytotoxicity of DTX in DTX-resistant PCa cells (PC3/DR and DU145/DR) and their parental sensitive cells (PC3 and DU145). B. The list of hypoxia-related lncRNAs from Pubmed and the top 80 upregulated lncRNAs in PC3/DR cells from RNA-seq (Jiang X, et al. Front Oncol, 2022). The data are presented as the mean ± S.D. of at least three independent experiments. *P < 0.05.
S2. A. The relative expression of lincROR was evaluated by qRT-PCR in PC3 and DU145 cells after being transfected with lincROR. B. DU145 cells were treated with different dosages of DTX (concentration of 0, 5, 10, 20, 40, and 80 nM) for 72 hours and cell viability was evaluated by a CCK-8 assay. C. The LDH release in the culture medium was detected in lincROR-transfected DU145 cells after DTX treatment. D. The expression of lincROR was evaluated in PC3/DR and DU145/DR cells after transfected with siROR #1 or #2. E. The cytotoxicity of DTX in DU145/DR cells was detected by CCK-8 assay after lincROR knockdown. F. The LDH release in culture medium was detected in lincROR-knockdown DU145/DR cells after DTX treatment. The data are presented as the mean ± S.D. of at least three independent experiments.
ARTICLE ABSTRACT
Emerging evidence has suggested that patients with metastatic prostate cancer will become resistant after receiving docetaxel (DTX) chemotherapy, but the specific regulatory mechanism is still unclear. lincROR is an important oncogenic long noncoding RNA which plays an important role in regulating tumor carcinogenesis and metastasis; however, the underlying mechanism of lincROR functioning in the DTX resistance process of prostate cancer remains largely unknown. In the current study, we found that lincROR is highly expressed in DTX-resistant prostate cancer cell lines and was associated with poor DTX response in patients with metastatic prostate cancer. By using loss- and gain-of-function experiments revealed that lincROR promotes prostate cancer cells growth and DTX resistance in vitro and in vivo. Mechanistic studies demonstrated that lincROR specifically interacts with and stabilizes MYH9 protein, which enhances β-catenin/hypoxia-inducible factor 1-alpha (HIF1α) pathways. Besides, HIF1α could bind with the promoter region of lincROR to activate its transcription, thus forming the lincROR/MYH9/HIF1α positive feedback loop. Moreover, lincROR could be packaged into exosomes in an heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1)-dependent manner and then disseminated chemoresistance phenotype to receipt cells. Overall, our study provides evidence supporting exosome-mediated lincROR activates the β-catenin/HIF1α positive feedback loop by targeting MYH9 protein, which may be exploited for anticancer therapy.
Our findings suggest that targeting hypoxia stress and chemoresistance for therapeutic purposes and lincROR could promote the improvement of treatment responses in patients with DTX-resistant prostate cancer.
