Pengchao Li

MiR-146a suppresses tumor growth and progression by targeting EGFR pathway and in a p-ERK-dependent manner in castration-resistant prostate cancer†‡

Castration‐resistant prostate cancer (CRPC) is a leading cause of cancer‐related deaths in elder men. This disease has limited therapeutic options and poor prognosis as the underlying molecular mechanisms are not clearly understood. Given the emerging roles of microRNA (miRNA) as a key regulator, we postulated that miRNA may play a significant role in CRPC formation.

microRNA-133 inhibits cell proliferation, migration and invasion in prostate cancer cells by targeting the epidermal growth factor receptor

It has been shown that regulation of EGFR expression in prostate cancer cells is mostly at the transcriptional level. microRNA-133 (miR-133) has long been recognized as a muscle-specific miRNA which may regulate myoblast differentiation and participate in many myogenic diseases. Recently, it has been reported that miR-133 is also involved in other tumors, such as bladder cancer, esophageal cancer and may regulate cell motility in these cancer cells. In the present study, we examined the expression and effects of miR-133 in two hormone-insensitive prostate cancer cell lines. The expression of miR-133a and miR-133b were analyzed by quantitative RT-PCR. After transfection of miR-133a and miR-133b, cell viability assay, luciferase assay, western blot analysis, cell migration and invasion assay were conducted in Du145 and PC3 cells. In this study, we showed that miR‑133a and miR-133b are expressed at the detection limit in two hormone-insensitive prostate cancer cell lines, PC3 and DU145. Ectopic expression of miR-133 inhibited cell proliferation, migration and invasion in these cells. We also provide the first evidence that miR-133 may target EGFR. Our study provided the first glimpse of the functional role of miR-133 in two hormone-independent prostate cancer cell lines. These results may add to our knowledge on the molecular basis of prostate cancer progression.

microRNA-21 modulates cell proliferation and sensitivity to doxorubicin in bladder cancer cells.

Transitional cell carcinomas (TCCs) of the urinary bladder are common malignancies with a high recurrence rate. Since microRNA-21 (miR-21) may contribute to tumorigenesis and chemoresistance in many cancer types, we aimed to investigate its efficacy in TCCs. The expression of miR-21 and its target PTEN was determined by real-time qRT-PCR and western blotting, respectively in tumor tissues as well as adjacent non-tumor mucosa. The effect of miR-21 on cell proliferation and chemosensitivity to doxorubicin were measured using the MTT method. Cell apoptosis induced by doxorubicin was investigated using flow cytometry in the T24 cell line. BCL-2, AKT and pAKT were detected by western blotting for analysis of potential mechanisms. miR-21 was significantly up-regulated in tumor tissues while PTEN was expressed in lower levels compared to non-tumor tissues. A negative correlation between expression of miR-21 and PTEN was established in vivo. Cell proliferation and chemoresistance to doxorubicin were promoted by overexpression of miR-21 in T24 cells. BCL-2 up-regulation could be achieved by miR-21 overexpression, which prevented T24 cells from apoptosis induced by doxorubicin. Furthermore, the miR-21 induced BCL-2 up-regulation could be cancelled by the PI3K inhibitor LY294002. These data verified the oncogenic role of miR-21 in TCCs and may usher in new therapeutic strategies in treating this disease.

Circulating miR-497 and miR-663b in plasma are potential novel biomarkers for bladder cancer

MicroRNAs (miRNAs), abundant and highly stable in the plasma, have been widely reported. This greatly pursued us to investigate whether plasma miRNAs could be considered as powerful biomarkers for diagnosing bladder cancer (BC). We performed a plasma miRNAs profile with the TaqMan Low Density Array, and a two-phase validation to detect the candidate miRNAs expression by quantitative PCR. The receiver operating characteristic curve (ROC) and the area under curve (AUC) were used to evaluate diagnostic accuracy. A total of eight plasma miRNAs abnormally expressed between BC patients and healthy controls in microarray analysis (i.e., elevated miRNAs for miR-505, miR-363 and miR-663b, and decreased for miR-99a, miR-194, miR-100, miR-497 and miR-1 in BC plasma). In further independent cohorts, miR-497 and miR-663b with significantly differential expression were confirmed. Moreover, the AUC, sensitivity and specificity were raised to 0.711 (95% CI = 0.641-0.780), 69.7% and 69.6%, respectively, when miR-497 and miR-663b were integrated. This is the first study systematically exploring the existence of specific plasma miRNAs as early diagnostic biomarkers for BC in Chinese population; and these findings supported that plasma miR-497 and miR-663b could be promising novel circulating biomarkers in clinical detection of BC.

A lentiviral sponge for miRNA-21 diminishes aerobic glycolysis in bladder cancer T24 cells via the PTEN/PI3K/AKT/mTOR axis.

Cancer cells exhibit the ability to metabolise glucose to lactate even under aerobic conditions for energy. This phenomenon is known as the Warburg effect and can be a potential target to kill cancer cells. Several studies have shown evidence for interplay between microRNAs and key metabolic enzyme effecters, which can facilitate the Warburg effect in cancer cells. In the present study, a microRNA sponge forcibly expressed using a lentiviral vector was utilised to knock down miR-21 expression in vitro. qPCR and Western blot assays were performed to evaluate the expression of a regulatory factor related to aerobic glycolysis and the signalling pathway it regulates. In bladder cancer specimens, expression levels of glycolysis-related genes [glucose transporter (GLUT)1, GLUT3, lactic dehydrogenase (LDH)A, LDHB, hexokinase (HK)1, HK2, pyruvate kinase type M (PKM) and hypoxia-inducible factor 1-alpha (HIF-1α)] were higher in tumour tissues than in adjacent tissues, suggesting the role of glycolysis in bladder cancer. miR-21 inhibition in bladder cancer cell lines resulted in reduction in tumour aerobic glycolysis. Decrease in glucose uptake and lactate production was observed upon expression of the miR-21 sponge, which promoted phosphatase and tensin homologue (PTEN) expression, decreased phosphorylated AKT and deactivated mTOR. Furthermore, messenger RNA (mRNA) and protein expression levels of glycolysis-related genes were also lower in miR-21 sponge cells compared to miR-21 control cells. Our findings suggest that miR-21 acts as a molecular switch to regulate aerobic glycolysis in bladder cancer cells via the PTEN/phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR pathway. Blocking miR-21 function can be an effective diagnostic and therapeutic approach either by itself or in combination with existing methods to treat bladder cancer.

Circular RNA circ-ITCH inhibits bladder cancer progression by sponging miR-17/miR-224 and regulating p21, PTEN expression

BackgroundCirc-ITCH is a circRNA generated from several exons of itchy E3 ubiquitin protein ligase (ITCH) and tumor suppressor served as a sponge for certain miRNAs targeting their parental transcripts of ITCH. However, the role of circ-ITCH in bladder cancer (BCa) was not reported. In the present study, we investigated the role of circ-ITCH in BCa.MethodsQuantitative real-time PCR was used to detect the expression of circ-ITCH and survival analysis was adopted to explore the association between circ-ITCH expression and the prognosis of BCa. BCa cells were stably transfected with lentivirus approach and cell proliferation, migration, invasion, cell cycle and cell apoptosis, as well as tumorigenesis in nude mice were performed to assess the effect of circ-ITCH in BCa. Biotin-coupled probe pull down assay, Biotin-coupled miRNA capture, Fluorescence in situ hybridization and Luciferase reporter assay were conducted to confirm the relationship between the circ-ITCH and the microRNA.ResultsIn the present study, we found that circ-ITCH, is down-regulated in BCa tissues and cell lines. BCa patients with low circ-ITCH expression had shortened survival. Enforced- expression of circ-ITCH inhibited cells proliferation, migration, invasion and metastasis both in vitro and in vivo. Mechanistically, we demonstrated that circ-ITCH up-regulates the expression of miR-17 and miR-224 target gene p21 and PTEN through ‘sponging’ miR-17 and miR-224, which suppressed the aggressive biological behaviors of BCa.Conclusionscirc-ITCH acts as a tumor suppressor by a novel circ-ITCH/miR-17, miR-224/p21, PTEN axis, which may provide a potential biomarker and therapeutic target for the management of BCa.

Functional promoter -94 ins/del ATTG polymorphism in NFKB1 gene is associated with bladder cancer risk in a Chinese population.

Background A functional -94 insertion/deletion polymorphism (rs28362491) in the promoter of the NFKB1 gene was reported to influence NFKB1 expression and confer susceptibility to different types of cancer. This study aims to determine whether the polymorphism is associated with risk of bladder cancer. Materials and methods TaqMan assay was used to determine genotype among 609 cases and 640 controls in a Chinese population. Logistic regression was used to assess the association between the polymorphism and bladder cancer risk, and quantitative real-time polymerase chain reaction was used to determine NFKB1 mRNA expression. Results Compared with the ins/ins/ins/del genotypes, the del/del genotype was associated with a significantly increased risk of bladder cancer [adjusted odd ratio (OR)  = 1.92, 95% confidence interval (CI)  = 1.42–2.59]. The increased risk was more prominent among subjects over 65 years old (OR  = 2.37, 95% CI  = 1.52–3.70), male subjects (OR  = 1.97, 95% CI = 1.40–2.79) and subjects with self-reported family history of cancer (OR  = 3.59, 95% CI  = 1.19–10.9). Furthermore, the polymorphism was associated with a higher risk of developing non-muscle invasive bladder cancer (OR  = 2.07, 95% CI  = 1.51–2.85), grade 1 bladder cancer (OR  = 2.40, 95% CI  = 1.68–3.43), single tumor bladder cancer (OR  = 2.04, 95% CI  = 1.48–2.82) and smaller tumor size bladder cancer (OR  = 2.10, 95% CI  = 1.51–2.92). The expression of NFKB1 mRNA in bladder cancer tissues with homozygous insertion genotype was higher than that with deletion allele. Conclusions In conclusion, the -94 ins/del ATTG polymorphism in NFKB1 promoter may contribute to the etiology of bladder cancer in the Chinese population.

Downregulation of Dicer, a component of the microRNA machinery, in bladder cancer.

Dysregulation of microRNA metabolism has been observed in a variety of human cancers. In this study, we evaluated the expression of the enzymes of the machinery Dicer, Drosha and DGCR8, in transitional cell carcinomas (TCCs) of the urinary bladder. The expression of Dicer, Drosha and DGCR8 was analyzed using semi-quantitative RT-PCR in clinical specimens from normal bladder mucosa, TCCs and their normal adjacent tissues (NATs). Immunohistochemistry was performed to compare the expression of Dicer in normal, TCCs and NATs. Our study demonstrated that Dicer mRNA levels in TCCs were significantly lower compared to normal samples and NAT samples. The immunohistochemistry results revealed that Dicer protein levels in TCCs were significantly downregulated compared to normal bladder mucosa and NATs. Our data demonstrated that Dicer is significantly downregulated in TCCs compared to paired NAT samples and normal samples, suggesting that reduced expression of Dicer may play an important role in bladder cancer.

Novel methods for the diagnosis and treatment of ejaculatory duct obstruction

Study Type – Therapy (case series)

Association of the Glutathione S-Transferase M1, T1 Polymorphisms with Cancer: Evidence from a Meta-Analysis

Background Glutathione S-transferases (GSTs) are a family of multifunctional enzymes that are involved in the metabolism of many xenobiotics, including a wide range of environmental carcinogens. While the null genotypes in GSTM1 and GSTT1 have been implicated in tumorigenesis, it remains inconsistent and inconclusive. Herein, we aimed to assess the possible associations of the GSTM1 and GSTT1 null genotype in cancer risks. Methods A meta-analysis based on 506 case-control studies was performed. Odds ratios (OR) with corresponding 95% confidence intervals (CIs) were used to assess the association. Results The null genotypes of GSTM1 and GSTT1 polymorphisms were associated with a significantly increased risk in cancer (for GSTM1: OR = 1.17; 95%CI = 1.14–1.21; for GSTT1: OR = 1.16; 95%CI = 1.11–1.21, respectively). When the analysis was performed based on their smoking history, the risk associated of GSTM1 null and GSTT1 null genotypes with cancer is further increased (for GSTM1: OR = 2.66; 95%CI = 2.19–3.24; for GSTT1: OR = 2.46; 95%CI = 1.83–3.32, respectively). Conclusions These findings indicate that GSTM1 and GSTT1 polymorphisms may play critical roles in the development of cancer, especially in smokers.