BackgroundFGD4 (Frabin) is an F-actin binding protein with GTP/GDP exchange activity specific for CDC42. It is involved in reorganization of the actin cytoskeleton, which requires both actin binding and CDC42 activating function of FGD4. Expression of FGD4 is altered in patients with heterogeneous hereditary motor and sensory neuropathies as a result of demyelination of peripheral nerves.MethodsIn this study, we examined the expression of FGD4 in prostate cancer specimens using immunohistochemistry and studied the function of FGD4 in maintaining cell phenotype, behavior and drug sensitivity using overexpression and siRNA-based silencing approaches. We used Mann-Whitney test for comparative analysis of FGD4 expression.ResultsOur results show that the expression of FGD4 is upregulated in cancerous prostates compared to the luminal cells in benign prostatic hyperplasia, although the basal cells showed high staining intensities. We noted a gradual increase in the staining intensity of FGD4 with increasing aggressiveness of the disease. Inhibition of expression of FGD4 using siRNAs showed reduced proliferation and cell cycle arrest in G2/M phase of androgen dependent LNCaP-104S and androgen refractory PC-3 cells. Inhibition of FGD4 also resulted in reduced cell migration and CDC42 activities in PC-3 cells whereas, ectopic expression of FGD4 induced cell migration, altered expression of mesenchymal and epithelial markers and activation of CDC42/PAK signaling pathway. Reduced expression of FGD4 improved sensitivity of LNCaP-104S cells to the anti-androgen drug Casodex and PC-3 cells to the microtubule stabilizing drug docetaxel.ConclusionsOur data demonstrate a tumor promoting and a cell migratory function of FGD4 in prostate cancer cells and that inhibition of FGD4 expression enhances the response for both androgen-dependent and independent prostate cancer cells towards currently used prostate cancer drugs.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-5096-9) contains supplementary material, which is available to authorized users.

Prostate cancer is the second leading cause of cancer-related deaths of men in the Western world. Despite recent advancement in genomics, transcriptomics and proteomics to understand prostate cancer biology and disease progression, castration resistant metastatic prostate cancer remains a major clinical challenge and often becomes incurable. MicroRNAs (miRNAs), about 22-nucleotide-long non-coding RNAs, are a group of regulatory molecules that mainly work through post-transcriptional gene silencing via translational repression. Expression analysis studies have revealed that miRNAs are aberrantly expressed in cancers and have been recognized as regulators of prostate cancer progression. In this critical review, we provide an analysis of reported miRNA functions and conflicting studies as they relate to expression levels of specific miRNAs and prostate cancer progression; oncogenic and/or tumor suppressor roles; androgen receptor signaling; epithelial plasticity; and the current status of diagnostic and therapeutic applications. This review focuses on select miRNAs, highly expressed in normal and cancer tissue, to emphasize the current obstacles faced in utilizing miRNA data for significant impacts on prostate cancer therapeutics.

Background Primary care is the ideal place to implement behaviour change interventions for weight management. However, most primary care physicians are not managing patient weight as a standard of care due to lack of knowledge, skills and reimbursement. Generating more physicians who are familiar and comfortable with providing weight management is essential in leveraging a global change. In our university free clinic, medical students provide healthy lifestyle counselling using shared decision making to each patient at every clinic visit. Objective Improve the efficacy of behaviour change interventions via increased patient responsiveness and adherence. Methods The needs assessment demonstrated a subpar patient response rate to check-ins regarding behavioural change goals. In the first and second interventions, check-in message structure and contact schedule were varied to maximize patient responsiveness and goal achievement. Results In the needs assessment, 58% of patients responded to follow-ups and 58% of patients accomplished their goal. The first intervention cycle resulted in an improvement of responsiveness to 70% and accomplishment of goals to 59%. The second intervention cycle resulted in an improvement of responsiveness to 78% and accomplishment of goals to 74%. Conclusions Messages that were frequent, unique, succinct and delivered within 4 weeks after the clinic visit resulted in the highest response rate and goal attainment. Other primary care clinics can use these interventions to increase patient completion of implemented behaviour changes for a healthier lifestyle.

Background: As many students do not have previous experience with electronic health records (EHRs), the Comprehensive Medical Care Outreach Team at the University of Central Florida repeatedly struggled to maintain an accurate and consistent record of patient visits, despite all volunteers attending a lecture-based training session prior to clinic day. This study evaluated changes in student EHR accuracy at this student-run clinic using alternative training methods. We hypothesized that small-group interactive learning would result in higher EHR accuracy than lecture-style learning. Methods: This study examined EHR accuracy through one year (2019) of data over four clinic sessions. EHR accuracy was defined as completion and correctness of various EHR parameters, consisting of electronically signing notes, medications, allergies, diagnoses, vital signs triage, and subjective, objective, assessment, and plan notes. For the first two clinics, students were trained using large group lecture-style learning, with a lecturer to volunteer ratio of 1:70. For the latter two clinics, students were trained in small-groups based on clinic role, in rooms with an average lecturer to volunteer ratio of 1:8. In these sessions, students then actively utilized the EHR by annotating a standardized patient case before the clinic. Results: Data shows significant differences (p<0.05) in EHR accuracy of large-group versus small-group training for 11 of 18 parameters, with all parameters demonstrating an increase in accuracy in the experimental groups. Conclusions: These results indicate that small-group, interactive learning affords greater EHR accuracy than large group lecture-style learning, suggesting more efficient ways to perform EHR training.

Increased activation of the GPCR CXCR4/CXCL12 signaling axis is commonly noted in metastatic prostate cancer and shows an association with poor prognosis. CXCR4, and its ligand, CXCL12/SDF-1a, are recognized as powerful mediators for tumor microenvironment remodeling and chemoprotection. LIM kinase 1 (LIMK1), a serine/threonine kinase, is an actin and microtubule modulatory protein that is also overexpressed in a variety of cancers including prostate cancer. Earlier, we showed that LIMK1 is involved in cell invasion and inhibition of LIMK1 expression reverted the invasive phenotype of PC3 prostate cancer cells. Activation of CXCR4/CXCL12 axis promotes activation of LIMK1 through RhoGTPAse pathway and promotes docetaxel resistance. Here we show that LIMK1 expression and functions have a positive correlation with CXCR4 expression and subcellular localization. We used metastatic prostate cancer cell lines PC3 and M12 and the non-tumorigenic prostate cell lines BPH and P69 to monitor expression and membrane localization of CXCR4 using western blots, flow cytometry and immunofluorescence analysis. Our analysis showed that cells with higher expression of LIMK1 (PC3) overexpress CXCR4, and that cell lines with low levels of LIMK1 (BPH and P69) express relatively lower amounts of CXCR4. Flow cytometric analysis showed a stronger surface staining of CXCR4 in the LIMK1 overexpressing PC3 cells compared to BPH cells. Next, we studied the effect of shRNA-mediated inhibition of LIMK1 expression on CXCR4 expression in PC3 or M12 cells. Western blot and immunofluorescence analysis showed noticeable reduction in CXCR4 levels, and its surface localization, as noted by flow cytometry, in LIMK1 shRNA transfected PC3 and M12 cells. To assess if the kinase activity of LIMK1 is essential for CXCR4 expression and surface localization, we treated these cells with LIMK1 specific kinase inhibitor BMS-5 and determined expression of CXCR4. Western blots and immunofluorescence analysis showed reduced expression of CXCR4 in treated cells compared to vehicle treated cells. Our observation indicates an indirect association between LIMK1 and CXCR4 expression and shows for the first time that expression of LIMK1 is required for the maintenance of CXCR4 expression. Our study demonstrates a novel positive feed back regulatory mechanism between LIMK1 and CXCR4 and suggest a possible combination treatment option through inhibition of LIMK1 expression and/or its kinase activity for improving chemosensitivity of prostate cancer cells with overactive CXCR4/CXCL12 axis. Citation Format: Richard Ottman, Lisa Ritchey, Ryan Herchan, Alexia Bossan, Ratna Chakrabarti. LIMK1 functions as a modulator of expression and targeting of CXCR4 in prostate cancer cells through a negative feedback loop. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1171.

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Hyperactivation of Rho family of GTPases including Rac, Cdc42 and Rho, as a result of deregulation of Rho guanine nucleotide exchange factors (GEF) is commonly noted in various cancers including prostate cancer. A number of GEFs are overexpressed in prostate and breast cancer cells and tissues, and show an association with poor prognosis. Earlier, we showed that a prolonged treatment with androgen receptor antagonist Casodex resulted in up regulation of a GEF FGD4, traditionally associated with hereditary motor and sensory neuropathies including Charcot-Marie-Tooth disease. FGD4 is a Cdc42 specific GEF and contains an actin binding domain FAB, in addition to the conserved FYVE domain, a DH domain for catalytic activity and two PH domains for targeting proteins to the membranes through phosphoinositide binding. Our study revealed that Casodex treatment of prostate cancer cells lead to down regulation of a microRNA cluster miR-17-92a that targets FGD4. Here we show that FGD4 is upregulated in cancerous prostate tissues compared to benign prostatic hyperplasia and PIN. FGD4 protein expression and altered localization gradually increase with increasing tumor grade and aggressiveness. Inhibition of FGD4 expression using siRNAs, reduced cell proliferation, resulted in a G2/M arrest, inhibited cell migration and reduced Cdc42 activity. Inhibition of FGD4 also improved sensitivity of androgen sensitive LNCaP cells to Casodex and PC-3 cells to the microtubule stabilizing drug docetaxel. Our data demonstrate a tumor promoting function of FGD4 in prostate cancer cells and that inhibition of FGD4 expression has a therapeutic benefit for both androgen-dependent and -independent prostate cancer cells. Citation Format: Alexia Bossan, Richard Ottman, Domenico Coppola, Ratna Chakrabarti. Functional role of RhoGEF FGD4 in promotion of aggressive prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4369.