miR-30b-5p suppresses prostate cancer progression by targeting FLVCR1 through the cAMP/PKA/CREB pathway

MicroRNAs are key post-transcriptional regulators implicated in tumor biology. Emerging evidence suggests that miR-30b-5p functions as a tumor suppressor in several human cancers; however, its contribution to prostate cancer remains poorly defined. Here, we report that miR-30b-5p expression is significantly reduced in prostate cancer tissues and cell lines, and its downregulation is closely associated with aggressive clinicopathological characteristics. Gain- and loss-of-function assays revealed that miR-30b-5p inhibits prostate cancer cell proliferation, migration, and invasion, while promoting apoptosis in vitro, and suppresses tumor growth in vivo. FLVCR1 was identified and validated as a downstream target of miR-30b-5p through bioinformatics prediction and luciferase reporter analysis. Mechanistically, FLVCR1 enhances malignant progression by activating the cAMP signaling pathway, and this oncogenic effect is markedly attenuated by ZnPP treatment. Collectively, our findings establish miR-30b-5p as a functional tumor suppressor that restricts prostate cancer progression by repressing FLVCR1-mediated cAMP signaling. miR-30b-5p may serve as a promising prognostic indicator and therapeutic target for patients with prostate cancer.