Purpose To investigate the involvement of hsa-microRNA-195-5p (miR-195) in progression and prognosis of human prostate cancer (PCa). Experimental Design qRT-PCR was performed to detect miR-195 expression in both PCa cell lines and clinical tissue samples. Its clinical significance was statistically analyzed. The roles of miR-195 and its candidate target gene ribosomal protein S6 kinase, 70kDa, polypeptide 1 (RPS6KB1) in PCa progression were confirmed based on both in vitro and in vivo systems. Results MiR-195 downregulation in PCa tissues was significantly associated with high Gleason score (P=0.001), positive metastasis failure (P<0.001) and biochemical recurrence (BCR, P<0.001). Survival analysis identified miR-195 as an independent prognostic factor for BCR-free survival of PCa patients (P=0.022). Then, we confirmed the tumor suppressive role of miR-195 through PCa cell invasion, migration and apoptosis assays in vitro, along with tumor xenografts growth, angiogenesis and invasion in vivo according to both gain-of-function and loss-of-function experiments. Additionally, RPS6KB1 was identified as a novel direct target of miR-195 through proteomic expression profiling combined with bioinformatic target prediction and luciferase reporter assay. Moreover, the re-expression and knockdown of RPS6KB1 could respectively rescue and imitate the effects induced by miR-195. Importantly, RPS6KB1 expression was closely correlated with aggressive progression and poor prognosis in PCa patients as opposed to miR-195. Furthermore, we identified MMP-9, VEGF, BAD and E-cadherin as the downstream effectors of miR-195-RPS6KB1 axis. Conclusion The newly identified miR-195-RPS6KB1 axis partially illustrates the molecular mechanism of PCa progression and represents a novel potential therapeutic target for PCa treatment.

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High-resolution optical microscopes that can break 180 nm in spatial resolution set to conventional microscopies are much-needed tools. However, current optical microscopes have to rely on exogenous fluorescent labels to achieve high resolution in biological imaging. Herein, we report near-resonance enhanced label-free stimulated Raman scattering (SRS) microscopy with a lateral resolution near 130 nm, in which the high-resolution image contrast originates directly from a low concentration of endogenous biomolecules, with sensitivity gains of approximately 23 times. Moreover, by using a 0.3-m-long optical fiber, we developed hyperspectral SRS microscopy based on spectral focusing technology. Attributed to enhancements in spatial resolution and sensitivity, we demonstrated high-resolution imaging of three-dimensional structures in single cells and high-resolution mapping of large-scale intact mouse brain tissues in situ. By using enhanced high-resolution hyperspectral SRS, we chemically observed sphingomyelin distributed in the myelin sheath that insulates single axons. Our concept opens the door to biomedical imaging with ~130 nm resolution.