Role of long noncoding RNA MALAT1 promotes the occurrence and progression of cutaneous squamous cell carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of long noncoding RNA MALAT1 in the occurrence and progression of cutaneous squamous cell carcinoma (CSCC).</p><p><b>METHODS</b>Fifty-five tissue samples of CSCC and 10 normal epidermal tissues were collected for examination of the expression of MALAT1 using q-PCR and in situ hybridization. Human CSCC A431 cells were transfected with small interfering RNAs (siNC, siMALAT1-1, and siMALAT1-2) using Lipofectamine2000 to knock down MALAT1 gene, and the changes in the cell migration, invasion, mobility and proliferation were analyzed using Transwell assay, wound healing assay, and CCK-8 assay; the changes in the expressions of the related factors of epithelial-mesenchymal transition (EMT), including E-cadherin, vimentin, and β-catenin, were detected using qRT-PCR.</p><p><b>RESULTS</b>Compared with normal tissues, CSCC tissues of different grades of differentiation all showed significantly increased expression of MALAT1 (P<0.001). In A431 cells, MALAT1 knockdown with siRNAs resulted in significantly lowered cell proliferation (P<0.001), migration (P<0.01), invasion (P<0.01), and mobility (P<0.01). Knocking down MALAT1 gene also caused significantly increased expressions of E-cadherin and β-catenin (P<0.01) and lowered the expression of vimentin (P<0.01) in A431 cells.</p><p><b>CONCLUSION</b>The long noncoding RNA MALAT1 promotes the occurrence and progression of CSCC and can potentially serve as a therapeutic target in treatment of CSCC.</p>

Differential responses to UVB irradiation in human keratinocytes and epidermoid carcinoma cells / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To examine UVB-induced responses in normal human keratinocytes (HaCaT) and epidermoid carcinoma cells (A431) at the cellular and molecular level, and investigated the protective effect of salidroside.</p><p><b>METHODS</b>Cells irradiated by UVB at various dosage and their viability was assessed by MTT assays, cell cycle was analysed by flow cytometry. The expression of NF-κB, BCL-2, and CDK6 after 50 J/m(2) UVB irradiation were detected by RT-PCR and western blotting.</p><p><b>RESULTS</b>Our results confirmed greater tolerance of A341 cells to UVB-induced damage such as cell viability and cell cycle arrest, which was accompanied by differential expression changes in NF-κB, BCL-2, and CDK6. UVB exposure resulted in HaCaT cells undergoing G(1)-S phase arrest. When treated with salidroside, HaCaT survival was significantly enhanced following exposure to UVB, suggesting great therapeutic potential for this compound.</p><p><b>CONCLUSION</b>Taken together, our study suggests that A431 respond differently to UVB than normal HaCaT cells, and supports a role for NF-κB, CDK6, and BCL-2 in UVB-induced cell G(1)-S phase arrest. Furthermore, salidroside can effectively protect HaCaT from UVB irradiation.</p>

Mechanisms of ultraviolet B irradiation-induced injuries in 16HBE cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the biological effects of ultraviolet B (UVB) irradiation on human bronchial epithelial cells (16HBE cells) and explore the possible mechanism.</p><p><b>METHODS</b>The survival rates of 16HBE cells were detected by MTT assay at 12 h after UVB irradiation at different doses (0, 10, 30, 50, 70, and 100 J/m(2)) or at 50 J/m(2) for different durations (2, 4, 8, 12, and 24 h). The DNA ladder was detected by agarose gel electrophoresis, the cell cycle changes were analyzed by flow cytometry, and the expression of nuclear factor-κB (NF-κB)/p65 protein was assayed by Western blotting following the exposures.</p><p><b>RESULTS</b>UVB irradiation of the cells resulted in lowered cell survival rates, DNA fragmentation, S phase arrest and up-regulation of NF-κB/p65 protein expression.</p><p><b>CONCLUSIONS</b>UVB irradiation can induce growth inhibition and apoptosis of 16HBE cells, in which process NF-κB protein may play a key role.</p>

Mechanisms of G2/M cycle arrest induced by topo IIalpha and II beta inhibitors in H460 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the mechanisms of G(2)/M cycle arrest induced by topo IIalpha and IIbeta inhibitors in H460 cells.</p><p><b>METHODS</b>The inhibitory effects of XK469, adriamycin and etoposide on H460 cell growth were analyzed by MTT assay. The changes in cell cycle and expressions of cdc2, phos-cdc2 and 14-3-3sigma proteins induced by these 3 topo II inhibitors were detected by flow cytometry and Western blotting, respectively.</p><p><b>RESULTS</b>Both of the two types of topo II inhibitor resulted in dose-dependent G(2)/M phase arrest and growth inhibition of H460 cells, but XK469 failed to induce 14-3-3sigma protein expression as adriamycin and etoposide did.</p><p><b>CONCLUSION</b>Topo IIalpha and topo IIbeta inhibitors induce growth inhibition of H460 cells possibly through two different mechanisms, namely the 14-3-3sigma-dependent pathway and the 14-3-3sigma-independent pathway, but further functional inhibition test of 14-3-3sigma is needed to confirm this hypothesis.</p>

Roles of p38 and ERK signaling pathway in cell apoptosis induced by UVB irradiation / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the involvement of p38 and ERK signal transduction pathways in UVB-induced cell apoptosis.</p><p><b>METHODS</b>HaCat cells were exposed to UVB irradiation for 1, 3, 5, 10, and 15 min, respectively, after which the cell survival was assessed using MTT assay, and the cell apoptosis observed under fluorescent microscope with Hoechst staining. Western blotting was used to examine the possible signal transduction pathway involved in the cell apoptosis following the exposures.</p><p><b>RESULTS</b>For the same incubation time following the exposure, the cell survival rate decreased gradually with the increase of UVB irradiation dose. At a fixed UVB irradiation dose, prolonged cell incubation following the exposure resulted in decreased cell survival rate, which, however, began to increase after the minimum rate was reached. At different UVB doses, cell exposure for 5 min caused the highest cell apoptosis rate, which peaked at 12 h during the post-irradiation incubation. The expressions of p38 and p53 were significantly decreased while p44/42 expression remained unchanged in the exposed cells.</p><p><b>CONCLUSION</b>UVB irradiation can induce growth inhibition and apoptosis of HaCat cells in a dose- and time-dependent manner, and p38 pathway other than ERK pathway is probably involved in UVB-induced cell apoptosis.</p>

Specific small interfering RNAs inhibit replication of hepatitis B virus / 南方医科大学学报

<p><b>OBJECTIVE</b>To obtain specific small interfering RNAs (siRNA) for hepatitis B virus (HBV) and evaluate their interfering effect.</p><p><b>METHODS</b>Three siRNAs were transfected into HepG2.2.15 cells, and the amount of HBV mRNA in the cell culture medium was quantified with real-time fluorescence quantitative RT-PCR. HBsAg in the culture media was assayed with Western blotting at different time points after transfection.</p><p><b>RESULTS</b>The cells transfected with specific siRNAs showed decreased levels of HBV mRNA and HBsAg (P<0.05), but those with nonspecific siRNA transfection as the negative control did not show such changes (P>0.05).</p><p><b>CONCLUSION</b>Specific siRNA can significantly inhibit protein expression and mRNA synthesis of HBV in HepG2.2.15 cells in vitro.</p>

Positron emission tomography with L-S-methyl-11C-methioine and its biodistribution / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the biodistribution of L-[S-methyl-(11)C]-methioine ((11)C-MET) and explore its clinical application in positron emission tomography (PET) for brain tumor detection.</p><p><b>METHODS</b>Twenty-four Wistar rats and divided into 6 equal groups and injected with (11)C-MET through the tail vein and killed by decollation at 5, 10, 20, 30 and 40 min after injection, respectively. The liver, brain, blood, heart, lung, kidney, and spleen were harvested to measure the radioactivity and calculate the biodistribution of (11)C-MET. PET imaging with (11)C-MET was performed in 6 normal volunteers and 30 patients with pathologically confirmed brain gliomas.</p><p><b>RESULTS AND CONCLUSION</b>(11)C-MET showed high blood uptake and a long retention in the tumor mass, therefore can be a valuable tracer for PET imaging of brain tumor and the hypophysis.</p>

Changes in immune function of dendritic cells infected by recombinant adenovirus containing Her2/neu gene of extracellular and transmembrane domain proteins / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the functional changes of dendritic cells (DCs) infected in vitro by 3 recombinant adenoviruses encoding Her2/neu extracellular first-receptor domain (Her2-ECDs), full-length extracellular domain (Her2-ECD), and extracellular and transmembrane domain (Her2-TM) proteins (rAdHer2-ECDs, rAdHer2-ECD and rAdHer2-TM, respectively).</p><p><b>METHODS</b>The expressions of the target proteins were detected with Western blotting. The level of both interleukin (IL)-12 in the supernatant of in vitro cultured DCs infected with recombined adenoviruses and interferon gamma (IFN-gamma) in the supernatant of the lymphocyte populations co-cultured with DCs were determined by enzyme-linked immunosorbent assay (ELISA). The capacity of the DCs to stimulate allogeneic T lymphocyte proliferation was assessed by mixed lymphocyte reaction, and the activity of cellular toxic T lymphocytes (CTL) were investigated by MTT assay.</p><p><b>RESULTS</b>Her2-ECDs, ECD and TM proteins were detected in the transfected DCs. Compared with the untransfected DCs, more abundant IL-12 production was detected in the supernatant of the DCs 5 days after transfection, but the IL-12 level showed no significant difference between the DCs infected with the 3 recombinant adenoviruses. IFN-gamma production increased gradually with passage of the time following DC-stimulated lymphocyte proliferation irrespective of infection of the DCs, and only the DCs infected with rAdHer2-TM seemed to result in significant difference in DC-mediated allogeneic T lymphocyte proliferation. The killing of breast cancer cell line with Her2 overexpression was more efficient with infected DCs priming autologous T lymphocyte to generate CTL than with uninfected DCs and those modified by SK-OV-3 cell fragment. CTL activity induced by rAdHer2-TM-infected DCs was the strongest, and breast cancer cell-killing activity was more efficient against cell line with Her2/neu-overexpression.</p><p><b>CONCLUSION</b>The DCs infected with the recombinant adenovirus encoding Her2/neu extracellular and transmembrane domains show enhanced anti-tumor effect and induce Her2/neu-specific CTL activity.</p>