miR-224-5p Contained in Urinary Extracellular Vesicles Regulates PD-L1 Expression by Inhibiting Cyclin D1 in Renal Cell Carcinoma Cells

Abstract

The abundant miRNAs in urinary extracellular vesicles (EVs) represent ideal reservoirs for biomarker discovery, especially in renal cell carcinoma (RCC). However, the content and biological functions of microRNAs contained in urinary EVs in RCC remain ambiguous. In this study, urinary EVs were isolated and characterized from RCC patients and healthy volunteers. Differentially expressed microRNAs in urinary EVs were screened by small RNA sequencing. The target gene and biological functions of selected microRNAs were investigated through multifaceted methods. Results indicated that miR-224-5p was significantly upregulated in urinary EVs of RCC patients compared to healthy volunteers. The overexpression of miR-224-5p inhibited RCC cell proliferation and induced cell cycle arrest. The gene CCND1 encoding cyclin D1 was identified as a direct target of miR-224-5p via prediction and validation. Moreover, the invasive and metastatic abilities of RCC cells were enhanced by miR-224-5p. Interestingly, miR-224-5p also increased the stability of PD-L1 protein by inhibiting CCND1. This effect could be transmitted via EVs and further promoted the resistance of RCC cells to T cell-dependent toxicity. In summary, urinary EVs containing miR-224-5p were identified as a potential biomarker in RCC. Regulation of PD-L1 protein expression by miR-224-5p through suppressing CCND1 elucidates new roles of miR-224-5p in RCC progression.

MiR-93-5p regulates tumorigenesis and tumor immunity by targeting PD-L1/CCND1 in breast cancer

“…Moreover, another mouse tumor model study suggested that cyclin D-CDK4 and the cullin 3-SPOP E3 ligase regulate the expression of PD-L1 protein via proteasome-mediated degradation and that CDK4/6 inhibitor treatment combined with anti-PD-1 immunotherapy enhanced tumor regression and markedly improved overall survival rates (38). Similarly, a study on a renal cell carcinoma also showed that cyclin D-CDK4/6 plays a rate-limiting role in regulating PD-L1 expression (39). Considering the immune-related possibilities of CCND1, our BRCA cell work focused on the correlation of PD-L1 and CCND1 and discovered high expression levels of PD-L1 and CCND1 in MDA-MB-231 cells.…”

Circulating RNA in Kidney Cancer: What We Know and What We Still Suppose

“…In another study, urinary EVs RNA from 6 RCC patients and 6 healthy volunteers were analyzed by sequencing. Among the differentially expressed miRNAs, miR-224-5p was significantly upregulated not only in urinary EVs, but also in cancer tissues, compared to paired adjacent tissues from the same RCC patients [70]. Notably, miR-224-5p was demonstrated to upregulate PD-L1 expression through the cyclin D1/SPOP pathway and to promote the resistance of RCC cells to T cell-dependent toxicity.…”

PD‐1/PD‐L1 inhibitors‐based treatment for advanced renal cell carcinoma: Mechanisms affecting efficacy and combination therapies

“… 71 Su Zeng et al demonstrated that the miR‐224‐5p expression in urinary extracellular vesicles was abnormally elevated in patients with RCC, and this elevation could inhibit the gene CCND1 encoding cyclin D1 and thereby downregulate the proteolytic hydrolysis of PD‐L1 mediated by the downstream cyclin D1/SPOP signaling pathway. 72 …”

“…71 Su Zeng et al demonstrated that the miR-224-5p expression in urinary extracellular vesicles was abnormally elevated in patients with RCC, and this elevation could inhibit the gene CCND1 encoding cyclin D1 and thereby downregulate the proteolytic hydrolysis of PD-L1 mediated by the downstream cyclin D1/SPOP signaling pathway. 72 Genetic alterations induced by the modification of histone methylation could affect PD-L1 expression by upregulating the expression of immunogenic endogenous retroviruses (πERVs) in RCC, especially ERV3-2. 73 Researchers also found that high vimentin expression in RCC was accompanied by high PD-L1 expression.…”