MicroRNA-214 targets PTK6 to inhibit tumorigenic potential and increase drug sensitivity of prostate cancer cells.

Prostate cancer is the most commonly diagnosed cancer in men with African American men disproportionally suffering from the burden of this disease. Biomarkers that could discriminate indolent from aggressive and drug resistance disease are lacking. MicroRNAs are small non-coding RNAs that affect numerous physiological and pathological processes, including cancer development and have been suggested as biomarkers and therapeutic targets. In the present study, we investigated the role of miR-214 on prostate cancer cell survival/migration/invasion, cell cycle regulation, and apoptosis. miR-214 was differentially expressed between Caucasian and African American prostate cancer cells. Importantly, miR-214 overexpression in prostate cancer cells induced apoptosis, inhibiting cell proliferation and colony forming ability. miR-214 expression in prostate cancer cells also inhibited cell migration and 3D spheroid invasion. Mechanistically, miR-214 inhibited prostate cancer cell proliferation by targeting protein tyrosine kinase 6 (PTK6). Restoration of PTK6 expression attenuated the inhibitory effect of miR-214 on cell proliferation. Moreover, simultaneous inhibition of PTK6 by ibrutinib and miR-214 significantly reduced cell proliferation/survival. Our data indicates that miR-214 could act as a tumor suppressor in prostate cancer and could potentially be utilized as a biomarker and therapeutic target

RARRES1 modulates angiogenesis.

<p>Human umbilical vein endothelial cells (HUVECs) were transfected with empty vector or RARRES1 expression vector. After 48 hours HUVECs were trypsinized and seeded on a matrigel at a density of 5×10³/well in triplicates. After 18h, tube-like structures were photographed. <b>A)</b> Representative photographs of tube-like structure. <b>B)</b> Quantitative analysis of total tube numbers; *p<0.01 vs. empty vector; #p <.05 vs. empty vector and PMA. <b>C)</b> PC3 cells were transfected with empty vector or RARRES1 expression vector. HUVECs were seeded on a matrigel at a density of 5×10³/well and treated with the conditioned media (CM) from PC3 transfected cells. Each group was in triplicate. After 18h, tube-like structures were photographed and quantitated. The quantitation results of total tube numbers are reported. <b>D)</b> Real time qPCR analysis of TSP1 and HIF1 expression on HUVECs treated with conditioned media from empty vector or RARRES1 expression vector transfected PC3 cells. Fold changes have been calculated by 2^^-(ΔΔCT) method, *p<0.05.</p

RARRES1 induces autophagy.

<p><b>A)</b> PC3 cells were plated in 8 well chamber slides and transfected with empty vector or RARRES1 expression vector. Cells were then fixed with parafomaldehyde and immunocytochemistry with antibodies, FLAG and LC3B was performed. Confocal images were taken at 20X magnification. <b>B)</b> Protein lysates from PC3 cells transfected with empty vector or RARRES1 expression vector were immunoblotted and immunoprobed with antibodies against autophagy markers, LC3B, ATG3, Beclin, FLAG and GAPDH. <b>C)</b> Prostate cancer cells C4-2 and PC3 cells were co-transfected with LC3B and empty vector or RARRES1 expression vector. Immunocytochemistry was performed using LC3B (green) and FLAG (red) antibodies and images were taken with 40X objective using Zeiss LSM 700 confocal microscope.</p

Mechanism of RARRES1 function.

<p>Based on our data and cited references, the outline of RARRES1’s role of tumor suppression in prostate cancer has been depicted. The green arrows indicate a positive induction and the red lines indicate repression. The black dashed arrows indicate the presence of intercellular signaling between the processes/molecules. The solid black arrows indicate the results we present in the paper to support our conclusion.</p

RARRES1 modulates ER stress and the expression of antioxidant enzymes.

<p><b>A)</b> PC3 cells were treated with tunicamycin after being transfected with empty vector or RARRES1 expression vectors. Immunoblot analysis was performed for ER stress with antibodies against GRP78, IRE-1, FLAG and GAPDH (loading control). <b>B)</b> Real time qPCR data of PC3 cells transfected with empty vector or RARRES1 expression vector. Fold changes have been calculated by 2^^-(ΔΔCT) method; *p<0.05. <b>C)</b> PC3 cells were transfected with empty vector or RARRES1 expression vector. Immunoblot analysis was performed for autophagy modulating signaling proteins, with antibodies against mTOR, SIRT1, RARRES1 and GAPDH (loading control). <b>D)</b> Immunoblot data with antibodies against acetylated and total forms of FOXO1 with protein lysates from cells transfected with empty vector or RARRES1 expression vector. <b>E)</b> Levels of antioxidant enzymes, catalase, Glutathione peroxidase (GPX), Manganese superoxide dismutase (MnSOD) after empty vector or RARRES1 expression vector transfection; *p<0.01.</p

MicroRNA profiling in prostate cancer--the diagnostic potential of urinary miR-205 and miR-214.

Prostate cancer (PCa) is the most common type of cancer in men in the United States, which disproportionately affects African American descents. While metastasis is the most common cause of death among PCa patients, no specific markers have been assigned to severity and ethnic biasness of the disease. MicroRNAs represent a promising new class of biomarkers owing to their inherent stability and resilience. In the present study, we investigated potential miRNAs that can be used as biomarkers and/or therapeutic targets and can provide insight into the severity and ethnic biasness of PCa. PCR array was performed in FFPE PCa tissues (5 Caucasian American and 5 African American) and selected differentially expressed miRNAs were validated by qRT-PCR, in 40 (15 CA and 25 AA) paired PCa and adjacent normal tissues. Significantly deregulated miRNAs were also analyzed in urine samples to explore their potential as non-invasive biomarker for PCa. Out of 8 miRNAs selected for validation from PCR array data, miR-205 (p<0.0001), mir-214 (p<0.0001), miR-221(p<0.001) and miR-99b (p<0.0001) were significantly downregulated in PCa tissues. ROC curve shows that all four miRNAs successfully discriminated between PCa and adjacent normal tissues. MiR-99b showed significant down regulation (p<0.01) in AA PCa tissues as compared to CA PCa tissues and might be related to the aggressiveness associated with AA population. In urine, miR-205 (p<0.05) and miR-214 (p<0.05) were significantly downregulated in PCa patients and can discriminate PCa patients from healthy individuals with 89% sensitivity and 80% specificity. In conclusion, present study showed that miR-205 and miR-214 are downregulated in PCa and may serve as potential non-invasive molecular biomarker for PCa

Pathway network of the genes targeted by differentially modulated miRNAs.

<p>Pathway network was constructed for commonly predicted target mRNAs of differentially modulated miRNAs (miR-205, miR-214, miR-221 and miR99b), by using Pathway Studio 9.0 (A) Commonly predicted miRNA targets with common regulators. (B) Directly interacting targets.</p

Differentially expressed miRNAs in Prostate Cancer Tissues.

*<p>miRNAs selected for tissue validation.</p

Prognostic accuracy of miR-205 and miR-214 in urine samples.

<p>The quantification of miR-205 and miR-214 together can enhance the diagnostic value and can be used to discriminate PCa patients from healthy individuals with 89% sensitivity and 80% specificity.</p