AQP8 promotes glioma proliferation and growth, possibly through the ROS/PTEN/AKT signaling pathway.

BACKGROUND: The aquaporin (AQP) family of proteins has been implicated in the proliferation and growth of gliomas. Expression of AQP8 is higher in human glioma tissues than in normal brain tissues and is positively correlated with the pathological grade of glioma, suggesting that this protein is also involved in the proliferation and growth of glioma. However, the mechanism by which AQP8 promotes the proliferation and growth of glioma remains unclear. This study aimed to investigate the mechanism and role of abnormal AQP8 expression in glioma development. METHODS: The dCas9-SAM and CRISPR/Cas9 techniques were used to construct viruses with overexpressed and knocked down AQP8, respectively, and infect A172 and U251 cell lines. The effects of AQP8 on the proliferation and growth of glioma and its mechanism via the intracellular reactive oxygen species (ROS) level were observed using cell clone, transwell, flow cytometry, Hoechst, western blotting, immunofluorescence, and real-time quantitative polymerase chain reaction assays. A nude mouse tumor model was also established. RESULTS: Overexpression of AQP8 resulted in an increased number of cell clones and cell proliferation, enhanced cell invasion and migration, decreased apoptosis and phosphatase and tensin homolog (PTEN) expression, and increased phosphorylated serine/threonine protein kinase (p-AKT) expression and ROS level, whereas the AQP8 knockdown groups showed opposite results. In the animal experiments, the AQP8 overexpression group had higher tumor volume and weight, whereas the AQP8 knockdown group had lower tumor volume and weight compared with those parameters measured in the control group. CONCLUSIONS: Our results preliminary suggest that AQP8 overexpression alters the ROS/PTEN/AKT signaling pathway, promoting the proliferation, migration, and invasion of gliomas. Therefore, AQP8 may be a potential therapeutic target in gliomas.

Alkaloids from Picrasma quassioides: An overview of their NMR data, biosynthetic pathways and pharmacological effects.

Picrasma quassioides, a member of the Simaroubaceae family, is the subject of research in numerous pharmacological and chemical studies. This plant mainly contains alkaloids, quassinoids and terpenoids. These molecules exhibit various pharmacological benefits, such as anti-inflammatory, anticancer, and anti-viral effects, on the cardiovascular system. Alkaloids make up the majority of these molecules. This review describes 127 alkaloid substances from P. quassioides. These alkaloids can be divided into the following classes: ß-carbolines, canthinones and alkaloid dimers. A compilation of their nuclear magnetic resonance spectroscopy data and possible biosynthetic pathways of these compounds and the pharmacological effects of P. quassioides are also included.

Antibacterial properties of Ag/TiO2/PDA nanofilm on anodized 316L stainless steel substrate under illumination by a normal flashlight.

The demand of medical materials for rapid and efficient elimination of bacteria has seen a dramatic surge over the past few years. In this study, antibacterial nanofilms with reactive oxygen species were generated by photocatalysis. To prepare these nanofilms, Ag and amorphous TiO2 nanoparticles decorated on polydopamine (PDA) were coated on three-dimensional (3D) nanopore arrays, which was fabricated on a substrate of anodized stainless steel. All the antibacterial tests were conducted with a household flashlight, which may be considered as a practical approach for antibacterial materials. The photoelectrochemical property of the 3D Ag/TiO2/PDA nanofilm on 316L stainless steel (Ag/TiO2/PDA SS) was about 15 times higher than that of the annealed Ag/TiO2/PDA SS, and consequently, it exhibited higher antibacterial activity. The enhanced photoelectrochemical property is attributed to the successful separation of electrons (amorphous TiO2) and holes (Ag nanoparticles). Further, when a plate containing 3D Ag/TiO2/PDA SS was irradiated with visible light just for 10 min, it immediately destroyed the bacteria in 106 CFU/mL without any bacterial colony. After five weeks, there were still no bacterial colonies in the plate corresponding to Ag/TiO2/PDA SS under visible light, while Ag/TiO2/PDA SS in dark had a negligible effect on the bacteria, i.e., the antibacterial mechanism through direct contact and ion dissolution was not efficient. The excellent antibacterial properties of 3D Ag/TiO2/PDA SS illuminated by flashlight provides an efficient, facile, and cost-effective technique for the development of antibacterial medical materials to meet the increasing demand of eliminating bacterial infections.

The absence of PRDM2 involved the tumorigenesis of somatotroph adenomas through regulating c-Myc.

Somatotroph adenoma is the main cause of acromegaly which have peripheral signs with growth of soft tissues and multiple comorbidities. Surgery and adjuvant therapy with somatostatin analogs (SSA) fail in more than 25% of patients. PRDM2, a tumor suppressor, plays an important role in cancer and obesity, including pituitary adenomas. In this study, we analyze the correlation of PRDM2 and oncogene c-Myc in 70 somatotroph adenomas according immunohistochemical staining, furthermore, we probed that whether PRDM2 participates in c-Myc signaling pathway in vitro experiment. 70 somatotroph adenomas patients were divided into low patients and high patients according to median of H-score of PRDM2 or c-Myc. Low PRDM2 patients had higher risk of invasive behavior, larger tumor volume and recurrence chance than high PRDM2 group (P = 0.015, P = 0.031, P = 0.017). High c-Myc patients had higher risk of invasive behavior, larger tumor volume and recurrence chance than low c-Myc group (P = 0.012, P = 0.002, P = 0.015). It was a negative correlation between H-score of PRDM2 and c-Myc (PRDM2 = -0.163 × c-Myc + 67.11, r = -0.407). The ability of cell proliferation was declined in a time dependent manner after overexpression of PRDM2 (PRDM2 group) compared to that in control GH3 cells (P < 0.05). Through flow cytometry assay, PRDM2 could induce the apoptosis and G2/M arrest in GH3 cell (both p < 0.05). Transwell experiment proved less trans-membrane cells in PRDM2 group than those in control group (415 ± 76 vs 145 ± 37, P < 0.01). RT-PCR and western blot both proved PRDM2 could inhibit the level c-Myc and elevate the levels of CDKN1A and CDKN1B. Combined with c-Myc inhibitor 10058-F4, PRDM2 further inhibited cell proliferation and induced more apoptosis in GH3 cell. Taken together, we found that PRDM2 negatively regulated the expression of c-Myc in somatotroph adenomas, and testified the synergism between PRDM2 gene therapy and c-Myc inhibitor in vitro experiment.

Toothache as a Warning Sign of Subarachnoid Hemorrhage Postmortem Findings.

The symptoms of sudden severe headache and/or diminished consciousness characterize the onset of aneurysmal subarachnoid hemorrhage (SAH). However, several studies have suggested that some patients show an atypical presentation at the onset: symptoms lacking sudden headache and diminished consciousness. These atypical symptoms can easily lead to misdiagnosis. This paper reported the death cases of acute aneurysmal subarachnoid hemorrhage with toothache as the first symptom, hoping to provide clinical evidence for the general public doctors to reduce the misdiagnosis and delayed diagnosis of SAH, improve the identification ability of SAH, and prevent such death events from happening again.

Aberrant expression of the sFRP and WIF1 genes in invasive non-functioning pituitary adenomas.

Non-functioning pituitary adenomas (NFPAs) are the most common pituitary tumors and mainly invade the sphenoid, cavernous sinus or dura mate. Aberrant regulation of the Wnt signaling pathway plays an important role in tumorigenesis. This study was designed to investigate the relationships between secreted frizzled-related proteins (sFRPs), WIF1 genes and the invasion of NFPAs by tissue microassays (TMAs) of samples from 163 patients. Significantly weaker staining of WIF1 and sFRP4 were detected in the invasive group compared with the non-invasive group by TMAs (p = 0.002, p < 0.001). Univariate analysis showed a significant correlation between tumor invasion and low expression of WIF1 and sFRP4 (p = 0.002, p < 0.001). A similar trend was observed when analyzing the mRNA and protein levels through RT-PCR and western blot experiments. Methylation of the WIF1 promoter was significantly increased in invasive NFPAs compared with the noninvasive group (p = 0.004). The average progression free survival time in the high WIF1 group was longer than that in the low WIF1 group (p = 0.025). Furthermore, RT-PCR measured the levels of 11 miRNAs targeting WIF1 according to the Targetscan database and PubMed. The levels of miRNA-137, miRNA-374a-5p and miRNA-374b-5p in the invasive group were 0.037-fold, 0.577-fold and 0.44-fold that of the noninvasive group (p = 0.003, p = 0.049 and p = 0.047). Overexpression of miRNA-137 could inhibit the proliferation and invasion of GH3 cells through cell viability and Transwell experiments (p < 0.05). Furthermore, the WIF1 level was upregulated after overexpression of miRNA-137 compared with miRNA-137-NC (control miRNA) in GH3 cells. Our data suggest that WIF1 may be potential biomarker for the aggressiveness of NFPAs. miRNA-137 plays an important role in the Wnt signaling pathway by affecting promoter methylation of WIF1.

Hybrid graphene/cadmium-free ZnSe/ZnS quantum dots phototransistors for UV detection.

Graphene-based optoelectronic devices have attracted much attention due to their broadband photon responsivity and fast response time. However, the performance of such graphene-based photodetectors is greatly limited by weak light absorption and low responsivity induced by the gapless nature of graphene. Here, we achieved a high responsivity above 103 AW-1 for Ultraviolet (UV) light in a hybrid structure based phototransistor, which consists of CVD-grown monolayer graphene and ZnSe/ZnS core/shell quantum dots. The photodetectors exhibit a selective photo responsivity for the UV light with the wavelength of 405 nm, confirming the main light absorption from QDs. The photo-generated charges have been found to transfer from QDs to graphene channel, leading to a gate-tunable photo responsivity with the maximum value obtained at V G about 15V. A recirculate 100 times behavior with a good stability of 21 days is demonstrated for our devices and another flexible graphene/QDs based photoconductors have been found to be functional after 1000 bending cycles. Such UV photodetectors based on graphene decorated with cadmium-free ZnSe/ZnS quantum dots offer a new way to build environmental friendly optoelectronics.

Detection of circulating tumor cells in patients with pituitary tumors.

BACKGROUND: Circulating tumor cells (CTCs) are tumor cells that have shed from a primary tumor and circulate in the peripheral blood. Recent experimental and clinical studies show that CTCs can be detected in early-stage disease. CASE PRESENTATION: We report three cases of pituitary adenoma (PA) in which tumor cells with particles were detected in the interstitial vascular compartment by transmission electron microscopy. Tumors were completely resected. Immunohistochemical analysis showed a ß-catenin score of 10.5 ± 1.5 in the three cases with CTCs compared with 2.4 ± 0.5 in 24 control adenomas. The Ki-67 labeling index was 2.1 ± 0.7 in CTCs vs. 0.2 ± 0.3 in control cases (p = 0.043), and the p53 score was 4.33 ± 1.3 vs. 0.31 ± 0.17 (p = 0.000). The E-cadherin score did not differ significantly between the two groups. CONCLUSIONS: CTCs can be detected in benign tumors such as PAs and not only in late-stage malignant tumors with apparent distant metastases. The present findings suggest that pituitary carcinomas develop from adenomas.

High-performance gas sensors based on a thiocyanate ion-doped organometal halide perovskite.

Thin films of a thiocyanate ion (SCN-)-doped organometal halide perovskite, CH3NH3PbI3-x(SCN)x, were used as a sensing material for developing high-performance gas sensors. The CH3NH3PbI3-x(SCN)x-based chemiresistor-type sensor can sensitively and selectively detect acetone and nitrogen dioxide (NO2) at room temperature with high sensitivities of 5.6 × 10-3 and 5.3 × 10-1 ppm-1. The limits of detection for acetone and NO2 were measured to be 20 ppm and 200 ppb. This sensor also exhibited excellent repeatability, and its environmental stability was greatly improved by doping the perovskite with SCN- ions.

RNF216 contributes to proliferation and migration of colorectal cancer via suppressing BECN1-dependent autophagy.

Originally identified as an E3 ligase regulating toll-like receptor (TLR) signaling, ring finger protein 216 (RNF216) also plays an essential role in autophagy, which is fundamental to cellular homeostasis. Autophagy dysfunction leads to an array of pathological events, including tumor formation. In this study, we found that RNF216 was upregulated in human colorectal cancer (CRC) tissues and cell lines, and was associated with progression of CRC. RNF216 promoted CRC cell proliferation and migration in vitro and in vivo, largely by enhancing proteasomal degradation of BECN1, a key autophagy regulator and tumor suppressor. RNF216 restricted CRC cell autophagy through BECN1 inhibition under nutritional starvation conditions. RNF216 knockdown increased the autophagy, limiting CRC cell proliferation and migration. Moreover, BECN1 knockdown or autophagy inhibition restored proliferation and migration of RNF216-knockdown CRC cells. Collectively, our results suggested that RNF216 promoted CRC cell proliferation and migration by negatively regulating BECN1-dependent autophagy. This makes RNF216 as a potential biomarker and novel therapeutic target for inhibiting CRC development and progression.

Exogenous IFN-beta regulates the RANKL-c-Fos-IFN-beta signaling pathway in the collagen antibody-induced arthritis model.

BACKGROUND: Although a variety of drugs have been used to treat the symptoms of rheumatoid arthritis (RA), none of them are able to cure the disease. Interferon ß (IFN-ß) has pleiotropic effects on RA, but whether it can be used to treat RA remains globally controversial. Thus, in this study we tested the effects of IFN-ß on RA patients and on collagen antibody-induced arthritis (CAIA) model mice. METHODS: The cytokine and auto-antibody expression profiles in the serum and synovial fluid (SF) from RA patients were assessed using enzyme-linked immunosorbent assay (ELISA) and compared with the results from osteoarthritis (OA) patients. Exogenous IFN-ß was administered to RA patients and CAIA model mice, and the therapeutic effects were evaluated. Endogenous IFN-ß expression in the joint bones of CAIA model mice was evaluated by quantitative real-time PCR (qRT-PCR). The effects of exogenous IFN-ß on CAIA model mice were assessed using a clinical scoring system, hematoxylin eosin and safranin-O with fast green counterstain histology, molybdenum target X-ray, and tartrate-resistant acid phosphatase (TRAP) staining. The RANKL-RANK signaling pathway was analyzed using qRT-PCR. The RAW 264.7 cell line was differentiated into osteoclasts with RANKL stimulation and then treated with exogenous IFN-ß. RESULTS: The expression of inflammatory cytokines (IFN-γ, IL-17, MMP-3, and RANKL) and auto-antibodies (CII antibodies, RF-IgM, and anti-CCP/GPI) were significantly higher in RA compared with OA patients. After IFN-ß intervention, some clinical symptoms in RA patients were partially alleviated, and the expression of IFN-γ, IL-17, MMP-3, and OPG) returned to normal levels. In the CAIA model, the expression of endogenous IFN-ß in the joint bones was decreased. After IFN-ß administration, the arthritis scores were decreased; synovial inflammation, cartilage, and bone destruction were clearly attenuated; and the expression of c-Fos and NFATc1 were reduced, while RANKL and TRAF6 expression was unchanged. In addition, exogenous IFN-ß directly inhibited RANKL-induced osteoclastogenesis. CONCLUSIONS: Exogenous IFN-ß administration immunomodulates CAIA, may reduce joint inflammation and, perhaps more importantly, bone destruction by inhibiting the RANKL-c-Fos signaling pathway. Exogenous IFN-ß intervention should be selectively used on RA patients because it may only be useful for RA patients with low endogenous IFN-ß expression.

Regulation of autophagy by E3 ubiquitin ligase RNF216 through BECN1 ubiquitination.

Autophagy is an evolutionarily conserved biological process involved in an array of physiological and pathological events. Without proper control, autophagy contributes to various disorders, including cancer and autoimmune and inflammatory diseases. It is therefore of vital importance that autophagy is under careful balance. Thus, additional regulators undoubtedly deepen our understanding of the working network, and provide potential therapeutic targets for disorders. In this study, we found that RNF216 (ring finger protein 216), an E3 ubiquitin ligase, strongly inhibits autophagy in macrophages. Further exploration demonstrates that RNF216 interacts with BECN1, a key regulator in autophagy, and leads to ubiquitination of BECN1, thereby contributing to BECN1 degradation. RNF216 was involved in the ubiquitination of lysine 48 of BECN1 through direct interaction with the triad (2 RING fingers and a DRIL [double RING finger linked]) domain. We further showed that inhibition of autophagy through overexpression of RNF216 in alveolar macrophages promotes Listeria monocytogenes growth and distribution, while knockdown of RNF216 significantly inhibited these outcomes. These effects were confirmed in a mouse model of L. monocytogenes infection, suggesting that manipulating RNF216 expression could be a therapeutic approach. Thus, our study identifies a novel negative regulator of autophagy and suggests that RNF216 may be a target for treatment of inflammatory diseases.

Partial splenectomy and use of splenic vein as an autograft for meso-Rex bypass: a clinical observational study.

BACKGROUND: Meso-Rex bypass (MRB) surgery is being increasingly used to treat chronic prehepatic portal hypertension secondary to extrahepatic portal vein thrombosis (EPVT) and cavernous transformation (EPVCT) in children. Rather than using the internal jugular vein (IJV, the traditional venous graft), we used an autogenous splenic vein segment graft for MRB. MATERIAL/METHODS: We examined 25 children with extrahepatic portal hypertension and a history of recurrent upper gastrointestinal (GI) variceal bleeding despite previous endoscopic sclerotherapy. All patients had melena, splenomegaly, hypersplenism, or some combination thereof. Left portal vein (LPV) patency was verified in 22 patients using intraoperative direct portography through the umbilical vein. Partial splenectomy was performed to enable the harvest of the splenic vein trunk, which was anastomosed between the superior mesenteric vein (SMV) and the left portal vein (LPV). All patients were followed for 12-48 months (mean=25.6 months) and no patients were lost to follow-up. RESULTS: Preoperative Doppler ultrasound (US) imaging indicated that 18/25 patients had adequate intrahepatic portal veins for shunting, with no blood flow in the LPVs of 7 patients. LPV patency in 22/25 patients was verified using intraoperative direct portography, with successful MRB. Shunting was converted into a portosystemic shunt in the remaining 3/25 patients with thrombosed LPVs. A Doppler US evaluation of the vein conduit revealed excellent postoperative flow. The patients' mean hemoglobin, platelet, and white blood cell counts increased significantly, and in all cases the endoscopic status obviously improved after shunting. Occlusion or narrowing occurred in 2/22 patients after discharge. At 12 months (for 1 patient) and 24 months (for 1 patient), the shunt was converted into a portosystemic shunt. The cumulative graft patency rate was 91% (20/22). CONCLUSIONS: Partial splenectomy and splenic vein autografting in MRB surgery can successfully resolve prehepatic portal hypertension and hypersplenism in children.

Adenylyl cyclase 6 activation negatively regulates TLR4 signaling through lipid raft-mediated endocytosis.

Proper intracellular localization of TLRs is essential for their signaling and biological function. Endocytosis constitutes a key step in protein turnover, as well as maintenance of TLR localization in plasma membrane and intracellular compartments, and thus provides important regulating points to their signaling. In this study, we demonstrate that adenylyl cyclase (AC) activation attenuates TLR4 signaling in a murine macrophage cell line (RAW 264.7) and bone marrow-derived macrophages when stimulated with LPS. We further show that the AC6 isoform plays a key role in negative regulation of TLR4 signaling by promoting protein degradation. TLR4 is normally endocytosed through the clathrin-mediated pathway, but concomitant AC6 activation shifts it to lipid raft-mediated endocytosis, which accelerates degradation of TLR4 and suppresses downstream signaling. Our studies unveil a new mechanism of negative regulation of TLR4 signaling through AC6-mediated endocytosis, which might provide a novel therapeutic approach for limiting inflammatory and autoimmune diseases.

BlyS: a potential hallmark of multiple myeloma.

Multiple myeloma (MM) is a plasma cell dyscrasia characterized by bone lesions and production of a paraprotein. B-lymphocyte stimulator (BLyS) and its receptor (BAFFR) were highly expressed on peripheral blood and bone marrow B cells in MM patients as compared to those with monoclonal gammopathy of unknown significance (MGUS) and healthy donors. Serum BLyS levels in MM patients were significantly higher than those in MGUS patients and healthy controls. BLyS expression was increased in bone marrow specimens from MM patients as ascertained by immunofluorescence. Furthermore, BLyS, together with IL-2 and IL-6, significantly promoted MM cell proliferation and BLyS receptor expression compared with that in the control group. Treatment with bortezomib, a therapeutic proteasome inhibitor induced apoptosis and repressed the proliferation of RPMI8226 and U266 cells through inhibition of NF-κB p65 and IκBα. These findings suggest that BLyS is involved in the immunopathogenesis of MM and may prove to be a hallmark of MM.

Meta-analysis of the efficacy and safety of the application of adjuvant material in the repair of anterior vaginal wall prolapsed.

INTRODUCTION: This study is a meta-analysis of the efficacy and safety of the application of adjuvant material in the repair of anterior vaginal wall prolapse and a sub-category analysis of the use of nonabsorbable synthetic mesh, biological graft and absorbable synthetic mesh. METHOD: Pubmed, Embase and Ovid databases were searched for published randomized controlled trials from 1980 to February 2012 on the treatment of anterior vaginal wall prolapse with adjuvant materials. A comprehensive meta-analysis applying Revman5.1 analysis software was performed. RESULTS: A total of 20 randomized controlled trials including 2,313 participants were recognized. The result showed that repair with adjuvant materials was better and more effective; nevertheless, use of adjuvant materials resulted in longer duration of surgery and more peri-operative bleeding when compared with the control group, but no significant differences were observed between the two groups regarding visceral injury, postoperative pain, urinary tract infection rate, new stress incontinence and new dyspareunia. CONCLUSION: Adjuvant material is worthy of clinical popularization, especially the biological graft type because of its lower anatomy failure rate and no difference in safety compared with the control group. However, exposure to adjuvant materials and erosion rate are high, which are the most important aspects to be improved.

Cross-reactivity of autoreactive T cells with MBP and viral antigens in patients with MS.

In this study, we detected the viral DNA of Human Herpes Virus 6 (HHV-6) in the sera and cell-free cerebrospinal fluid (CSF) of Chinese multiple sclerosis (MS) patients. The results revealed that the copy numbers of serum HHV-6 viral DNA were higher in MS than in normal subjects (NS) or in other neurologic diseases (OND). We also found that in the MS subjects, most T cells recognizing myelin basic protein (MBP) were cross-reactive and could be activated by a synthetic peptide corresponding to residues of HHV-6 or EBV. The estimated precursor frequency of these cross-reactive T cells recognizing both peptides, MBP and HHV-6 or EBV, was significantly elevated in MS compared with that in controls. More significant was the presence of CD8+ cytotoxic cross-reactive T cells, as they could directly induce injury to oligodendrocytes that are known to express both MBP and MHC class I molecules. The study provides important evidence for understanding the potential role of HHV-6 or EBV infection in the pathogenesis of MS.

Osteopontin mediates dense culture-induced proliferation and adhesion of prostate tumour cells: role of protein kinase C, p38 mitogen-activated protein kinase and calcium.

Cells growing in high density were observed to undergo a variety of responses due to cell-cell contact, pericellular hypoxia, etc. In order to investigate the influence of cell density on cell proliferation and adhesion and to elucidate possible mechanisms, we tested the growth ability of human prostate tumour (PC-3M) cells in dense culture and the influences of density on cell adhesion. Our results demonstrate that increasing cell density exerted stress on PC-3M cells, which decreased cell proliferation in dense cultures, but tended to facilitate tumour metastasis since cell adhesion ability was elevated and the cells showed an increased growth rate after being moved to a favourable growth environment. We conclude that higher cell density-mediated pericellular hypoxia was an important factor inducing expression of the intrinsic hypoxia marker osteopontin, another mechanism contributing to cell adhesion enhancement in PC-3M cells. In addition, cell density enhanced adhesion ability due to the activation of p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase C. Intracellular calcium also played positive roles at least partially through activating p38 MAPK.

siRNA directed against c-Myc inhibits proliferation and downregulates human telomerase reverse transcriptase in human colon cancer Colo 320 cells.

The c-Myc and human telomerase reverse transcriptase gene (hTERT) gene are frequently deregulated and overexpressed in malignancy. hTERT activity is induced by c-Myc and strategies designed to inhibit c-Myc expression in cancer cells may have considerable therapeutic value. We designed and used a short hairpin RNA to inhibit c-Myc expression in Colo 320 cells and validated its effect on cell proliferation. In this study, four c-Myc-shRNA expression vectors were constructed and introduced into Colo 320 cells. The effects of c-Myc silencing on tumor cell growth was assessed by soft agar assay and DNA synthesis experiments. The expressions of c-Myc and hTERT were also assessed by real-time reverse transcription-polymerase chain reaction and Western blot analysis. Upon transient transfection with plasmid encoding shRNA, it was found that expression of c-Myc and hTERT decreased in shRNA-transfected cells. The downregulation of c-Myc and hTERT inhibited cell growth, shortened telomere lengths, and suppressed telomerase activity. In conclusion, our findings demonstrate that shRNA of c-Myc can inhibit the DNA replication in Colo 320 cells effectively and reduce telomere length and telomerase activity, therefore, it could be used as a new potential anticancer tool for therapy of human colon cancer.

Depletion of c-Myc inhibits human colon cancer colo 320 cells' growth.

Human colon cancer is the leading cause of cancer death in both men and women worldwide. The c-Myc gene is frequently deregulated and overexpressed in this malignancy, and strategies designed to inhibit c-Myc expression in cancer cells may have considerable therapeutic value. We design and use short hairpin RNA (shRNA) to inhibit c-Myc expression in Colo 320 cells and validat its effect on cell proliferation. In this study, four c-Myc-shRNA expression vectors were constructed and introduced into Colo 320 cells, and the cell cycle and apoptotic cells were analyzed by flow cytometry. The effects of c-Myc silencing on tumor-cell growth was assessed by the soft agar assay and by DNA synthesis experiments. Expression of c-Myc was also assessed by real-time reverse transcription polymerase chain reaction and Western blot analysis. Upon transient transfection with plasmid-encoding shRNA, it was found that expression of c-Myc decreased in shRNA-transfected cells, and the downregulation of c-Myc inhibited cell growth and induced apoptosis in Colo 320 cells. c-Myc downregulation also increased cell population in the G0-G1 phase. In conclusion, our findings demonstrate that shRNA can inhibit the DNA replication and induce apoptosis in Colo 320 cells effectively and, therefore, could be used as a new potential anticancer tool for the therapy of human colon cancer.