LINC00893 inhibits the progression of prostate cancer through miR-3173-5p/SOCS3/JAK2/STAT3 pathway.

BACKGROUND: Prostate cancer (PCa) is one of the most common malignant tumors in the male urinary system. In recent years, the morbidity and mortality of PCa have been increasing due to the limited effects of existing treatment strategies. Long non-coding RNA (lncRNA) LINC00893 was reported to inhibit the proliferation and metastasis of papillary thyroid cancer cells, but its role in PCa has not been reported. This study aims to investigate the role and underlying mechanism of LINC00893 in regulating the progression of PCa cells. METHODS: We first compared LINC00893 expression levels between PCa tissues and normal prostate tissues through TCGA database. The relative LINC00893 expression levels were further validated in 66 pairs of PCa tissues and para-cancerous normal tissues, as well as in PCa cell lines. Gain-of-function experiment was performed by transfecting PCa cell with LINC00893 expression vector, and CCK (Cell count kit)-8, 5-Ethynyl-2'-deoxyuridine (EdU) incorporation, colony information and transwell assays were conducted to assess the functional phenotypes. Dual-luciferase reporter, RNA-binding protein immunoprecipitation (RIP) and RNA pull-down assays were performed to evaluate the molecular interactions. RESULTS: LINC00893 was downregulated in PCa tissues and cell lines, and patients with low expression of LINC00893 were associated with a poorer overall survival rate. LINC00893 overexpression hindered the proliferation, epithelial-mesenchymal transition (EMT) as well as the migratory ability of PCa cells, and suppressed the tumorigenesis of PCa cells in nude mice. We further demonstrated that LINC00893 acted as a sponge for miR-3173-5p and inhibited its activity, which in turn regulated the suppressor of cytokine signaling 3 (SOCS3)/Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling axis. CONCLUSIONS: Our study demonstrated that LINC00893 suppresses the progression of PCa cells through targeting miR-3173-5p/SOCS3/JAK2/STAT3 axis. Our data uncovers a novel tumor-suppressor role of LINC00893 in PCa, which may serve as a potential strategy for targeted therapy in PCa.

miR-145-5p Modulates Gefitinib Resistance by Targeting NRAS and MEST in Non-Small Cell Lung Cancer.

OBJECTIVE: microRNAs may play essential roles in the development and drug resistance of non-small cell lung cancer (NSCLC). However, their functions and mechanisms are not fully understood. Our goal was to define the role of miR-145-5p in the gefitinib resistance of NSCLC. MATERIALS AND METHODS: An A549 gefitinib-resistant cell line and xenograft nude mice were used in this study. The expression of miR-145-5p and its targets, NRAS and MEST, were detected and measured by qPCR, Western blot, RNA-FISH, or immunofluorescence analysis. RESULTS: miR-145-5p was downregulated in gefitinib-resistant A549 cells (A549/Gef R). Overexpression of miR-145-5p enhanced the sensitivity to gefitinib and inhibited cell proliferation and invasion in A549/Gef R. miR-145-5p was also significantly reduced in LUAD and LUSC clinical samples and closely associated with a favorable prognosis, according to the UALCAN and TCGA databases. Moreover, NRAS and MEST were found to be downstream target genes of miR-145-5p and to function as oncogenes in NSCLC samples, and gefitinib resistance could be improved following the interference of these two molecules. CONCLUSION: miR-145-5p improves the sensitivity of acquired gefitinib-resistant cells to gefitinib via inhibiting NRAS and MEST expression. The miR 145-5p-NRAS/MEST axis in NSCLC provides insights for the development of a NRAS/MEST targeting therapeutic approach to overcome gefitinib resistance in NSCLC patients.

NDRG2 acts as a negative regulator downstream of androgen receptor and inhibits the growth of androgen-dependent and castration-resistant prostate cancer.

Castration resistance is a major issue during castration therapy for prostate cancer and thus more effective treatment are needed for castration-resistant prostate cancer (CRPC). NDRG2 (N-Myc downstream regulated gene 2), a recently identified tumor suppressor, was previously shown to inhibit the proliferation and invasion of prostate cancer, but whether NDRG2 is involved in CRPC remains to be known. Because androgen receptor (AR) axis plays an important role in castration resistance, we evaluate the role of NDRG2 in AR signaling and CRPC. Immunohistochemistry examination of prostate cancer tissues demonstrated that the expression of NDRG2 is negatively correlated with that of AR and c-Myc. Furthermore, AR negatively regulates NDRG2, as well as alters levels of c-Myc and prostate specific antigen (PSA). Forced expression of NDRG2 significantly inhibits the in vitro growth of androgen-dependent and castration-resistant prostate cancer cells; this was accompanied by alterations in PSA, but not by those of AR and c-Myc. Finally, by mimicking castration therapy in a xenograft mouse model, we showed that lentivirus-mediated NDRG2 overexpression efficiently overcomes castration resistance. Thus, by acting as a negative regulator downstream of AR, NDRG2 may emerge as a potential therapy molecule for CRPC.

Up-regulation of pVHL along with down-regulation of HIF-1α by NDRG2 expression attenuates proliferation and invasion in renal cancer cells.

The majority of renal cell carcinomas (RCCs) are characterized by loss of function of the tumor suppressor gene von Hippel Lindau (VHL), which acts as ubiquitin ligase for hypoxia-inducible factor-1α (HIF-1α). In the absence of VHL, HIF-1α protein becomes stabilized and contributes to tumorigenesis. Recent data demonstrate the antitumor efficacy of VHL promoter in RCC cells. This study demonstrates that N-Myc downstream-regulated gene 2 (NDRG2) is a potential regulator of VHL. NDRG2 is involved in proliferation and invasion of cancer cell, furthermore it is frequently down-regulated in renal cell carcinoma. Herein we evaluated the effect of NDRG2 overexpression on proliferation and invasion in human renal cancer cells. The human renal cancer cell line 786-O and A498 were infected with Ad-NDRG2 or Ad-LacZ. Overexpression of NDRG2 not only inhibited the growth of the cells, but also suppressed the invasion. Further study showed that the tumor suppressor gene VHL were up-regulated, whereas transcription factor HIF-1a and vascular endothelial growth factor (VEGF) were down-regulated in 786-O cells infected by Ad-NDRG2. Finally, in a nude mouse model, intratumoral injections of Ad-NDRG2 every 3 days for a total of seven times significantly inhibited the growth and angiogenesis of xenografted 786-O tumors. In conclusion, these data indicate that NDRG2 may be involved in proliferation and invasion by impacting the expression of VHL and HIF-1α. NDRG2 may be an attractive therapeutic target for renal cell carcinoma.

Overexpression of N-Myc downstream-regulated gene 2 (NDRG2) regulates the proliferation and invasion of bladder cancer cells in vitro and in vivo.

N-Myc downstream-regulated gene 2 (NDRG2) is a candidate tumor suppressor gene, which plays an important role in controlling tumor growth. The aim of this study was to investigate the expression of NDRG2 gene in bladder cancer (BC) tissues and several bladder cancer cell lines, and to seek its clinical and pathological significance. Ninety-seven bladder carcinoma and 15 normal bladder tissue sections were analyzed retrospectively with immunohistochemistry. The human bladder cancer cell line T24 was infected with LEN-NDRG2 or LEN-LacZ. The effects of NDRG2 overexpression on T24 cells and T24 nude mouse xenografts were measured via cell growth curves, tumor growth curves, flow cytometric analysis, western blot and Transwell assay. NDRG2 was highly expressed in normal bladder tissue, but absent or rarely expressed in cacinomatous tissues (χ(2)=8.761, p < 0.01). The NDRG2 level was negatively correlated with tumor grade and pathologic stage(r=-0.248, p < 0.05), as well as increased c-myc level (r=-0.454, p< 0.001). The expression of NDRG2 was low in the three BC cell lines. T24 cells infected with LEN-NDRG2 showed inhibition of proliferation both in vitro and in vivo, and NDRG2 overexpression can inhibit tumor growth and invasion in vitro.

Effect of early adrenal vein ligation on blood pressure and catecholeamine fluctuation during laparoscopic adrenalectomy for pheochromocytoma.

OBJECTIVE: To define whether previous control of the adrenal vein is a crucial procedure in laparoscopic adrenalectomy for pheochromocytoma. METHODS: From January 2000 to December 2010, 114 patients with pheochromocytoma who underwent laparoscopic adrenalectomy through transperitoneal or retroperitoneal approach were included. The patients were divided into 2 groups randomly (group 1: dissection after ligation; group 2: dissection before ligation). Blood samples for the measurement of catecholamines levels using high performance liquid chromatography were taken at the following time points: t1, before anesthesia; t2, during manipulation-extraction of pheochromocytoma; t3, after removal of pheochromocytoma. The blood pressure fluctuation was recorded. RESULTS: Laparoscopic adrenalectomy was successfully performed on 113 patients with 1 elective open conversion because of dense peritumor adhesions. The operating time ranged from 80 to 150 minutes (mean 108, 102 in group 1, 110 in group 2). Mean blood loss ranged from 20 to 500 mL (mean 120 mL, 110 in group 1, 125 in group 2). The concentrations of plasma catecholamines between the 2 groups had no statistical differences. The blood pressure fluctuation incidence between the 2 groups had no marked difference. But the incidence increased with high functionary grade, and the difference was significant (P = .043). CONCLUSION: This study demonstrated that previous control of the adrenal vein was not a determinate factor in dealing with dangerous hypertension during laparoscopic adrenalectomies.

Suppression of invasion and metastasis of prostate cancer cells by overexpression of NDRG2 gene.

N-myc downstream regulated gene 2 (NDRG2) is involved in invasion and metastasis of cancer, furthermore it is frequently down-regulated in prostate cancer. Herein we evaluated the effect of NDRG2 overexpression on invasiveness and bone destruction in prostate cancer. The human prostate cancer cell line PC-3 and DU145 were infected with Ad-NDRG2 or Ad-LacZ. Overexpression of NDRG2 not only inhibited the growth of the cells, but also suppressed invasiveness of the cells in an in vitro assay. PC-3 cells infected with Ad-NDRG2 or Ad-LacZ were injected into the tibias of nude mice. Four weeks later, we found the mice injected with PC-3 cells overexpressing NDRG2 had smaller tumors and less bone destruction. These results demonstrate that NDRG2 overexpression can inhibit tumor growth and invasion, furthermore, it can decrease bone destruction caused by prostate cancer bone metastasis.

Inhibition of N-myc downstream-regulated gene 2 in prostatic carcinoma.

To study the expression of N-myc Downstream Regulated Gene-2 (NDRG2) in prostatic carcinoma (PCA) tissue and in different PCA cell lines, and to investigate its clinical and pathological implications, 144 PCA and benign prostatic hyperplasia (BPH) tissue sections were analyzed retrospectively with immunohistochemistry (S-P method). The expression levels of NDRG2 and c-Myc in prostate cell lines were detected through Western blot. The effects of adenovirus-mediated NDRG2 on PC3 cells and PC3 nude mouse xenografts was observed through cell growth curves, tumor growth curves, flow cytometry (FCM), transmission electron microscopy (TEM) and TUNEL staining. The NDRG2 gene was highly expressed in BPH tissues, but not in carcinomatous ones (χ(2)=25.98, p < 0.001). Furthermore, positive expression of NDRG2 was negatively correlated with the Gleason score (r = -0.445, p< 0.001) and the c-myc level (r = -0.311, p < 0.001). However, positive expression of NDRG2 was not correlated with pTNM tumor stages or the serum concentration of prostate-specific antigen (PSA) (p > 0.05). The expression of the NDRG2 genes was low in the three PCA cell lines. PC3 cells infected by pAD-cmv-NDRG2 showed inhibition of proliferation both in vitro and vivo. To sum up, NDRG2 may be involved in the carcinogenesis and progression of PCA. Moreover, adenovirus-mediated NDRG2 can suppress the proliferation of PC3 cells significantly both in vitro and in vivo. These results indicate that NDRG2 may become a new target gene for PCA diagnosis and therapy.