Repurposed benzydamine targeting CDK2 suppresses the growth of esophageal squamous cell carcinoma / 医学前沿

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer death worldwide. It is urgent to develop new drugs to improve the prognosis of ESCC patients. Here, we found benzydamine, a locally acting non-steroidal anti-inflammatory drug, had potent cytotoxic effect on ESCC cells. Benzydamine could suppress ESCC proliferation in vivo and in vitro. In terms of mechanism, CDK2 was identified as a target of benzydamine by molecular docking, pull-down assay and in vitro kinase assay. Specifically, benzydamine inhibited the growth of ESCC cells by inhibiting CDK2 activity and affecting downstream phosphorylation of MCM2, c-Myc and Rb, resulting in cell cycle arrest. Our study illustrates that benzydamine inhibits the growth of ESCC cells by downregulating the CDK2 pathway.

Advances of the regulatory mechanism of cyclin, cyclin- dependent kinases and related kinase inhibitors in cell cycle progression / 生物工程学报

Cell cycle plays a crucial role in cell development. Cell cycle progression is mainly regulated by cyclin dependent kinase (CDK), cyclin and endogenous CDK inhibitor (CKI). Among these, CDK is the main cell cycle regulator, binding to cyclin to form the cyclin-CDK complex, which phosphorylates hundreds of substrates and regulates interphase and mitotic progression. Abnormal activity of various cell cycle proteins can cause uncontrolled proliferation of cancer cells, which leads to cancer development. Therefore, understanding the changes in CDK activity, cyclin-CDK assembly and the role of CDK inhibitors will help to understand the underlying regulatory processes in cell cycle progression, as well as provide a basis for the treatment of cancer and disease and the development of CDK inhibitor-based therapeutic agents. This review focuses on the key events of CDK activation or inactivation, and summarizes the regulatory processes of cyclin-CDK at specific times and locations, as well as the progress of research on relevant CDK inhibitor therapeutics in cancer and disease. The review concludes with a brief description of the current challenges of the cell cycle process, with the aim to provide scientific references and new ideas for further research on cell cycle process.

Artesunate inhibits proliferation of glioblastoma cells by arresting cell cycle / 中国中药杂志

Glioblastoma is a common brain tumor and the overall survival rate of the patients is very low, so it is an effective way to develop the potential chemotherapy or adjuvant chemotherapy drugs in glioblastoma treatment. As a well-known antimalarial drug, artesunate(ARTs) has clear side effects, and recently it has been reported to have antitumor effects, but rarely reported in glioblastoma. Different concentrations of ARTs were used to treat the glioblastoma cells, and then the inhibitory effect of ARTs on glioblastoma proliferation was detected by MTT assay; Ki67 immunofluorescence assay was used to detect the proliferation of cells; Soft agar experiment was used to explain the clonal formation abilities ; Flow Cytometry was used to detect the cell cycle; and Western blot assay was used to determine the expression of key cell cycle protein. MTT assay results indicated that ARTs-treated glioblastoma cell A172, U251, U87 were significantly inhibited in a time-and-dose dependent manner as compared to the control group(DMSO treatment group). Soft agar experiment showed that ARTs could significantly reduce the clonal formation ability of glioblastoma. Furthermore, Flow cytometry analysis showed that ARTs could obviously increase the cell proportion in G₀/G₁ phase and reduce the cell proportion in S phase. Western blot results showed that the expressions of cell cycle-related proteins CDK2, CDK4, cyclin D1 and cyclin B1 were all obviously down-regulated. Above all, ARTs may inhibit the proliferation of glioblastoma cells by arresting cell cycle in G₀/G₁ phase through down-regulating the expression of CDK2, CDK4, cyclin D1, cyclin B1. These results may not only provide a novel method for rediscovering and reusing ARTs but also provide a new potential drug for treating glioblastoma.

Correlation between cyclin-dependent kinase inhibitor p27kip1 and trastuzumab-resistance in gastric cancer / 中南大学学报(医学版)

OBJECTIVE@#To investigate the correlation between cyclin-dependent kinase inhibitor p27kip1 and trastuzumab-resistance in gastric cancer.
@*METHODS@#We selected HER2-overexpressed human gastric cancer cell line NCI-N87 to establish trastuzumab-resistant NCI-N87/TR cell line by stepwise exposure to different doses of trastuzumab. The 50% inhibitory concentration (IC(50)) of trastuzumab and resistance index (RI) were calculated or analyzed by MTT assay. The expression levels of cdk2 and p27kip1 were detected by Western blot. After the treatment with cdk2 inhibitor (Purvalanol A), the expression levels of relevant proteins in NCI-N87/TR cells were detected by Western blot, and the sensitivity to trastuzumab was analyzed by MTT assay. 
@*RESULTS@#Compared with NCI-N87 cells, the expression of cdk2 was significantly increased in NCI-N87/TR cells (P<0.001), while the expression of p27kip1 showed a significant decrease (P<0.001). Restoration of the p27kip1 protein expression by cdk2 inhibitor (Purvalanol A) increased the sensitivity of NCI-N87/TR to trastuzumab.
@*CONCLUSION@#Down-regulation of p27kip1 might be a mechanism for triggering trastuzumab resistance to gastric cancer cell line NCI-N87.

Repetitive magnetic stimulation promotes neural stem cells proliferation by upregulating MiR-106b in vitro / 华中科技大学学报（医学）（英德文版）

Neural stem cells (NSCs) proliferation can be influenced by repetitive transcranial magnetic stimulation (rTMS) in vivo via microRNA-106b-25 cluster, but the underlying mechanisms are poorly understood. This study investigated the involvement of microRNA-106b-25 cluster in the proliferation of NSCs after repetitive magnetic stimulation (rMS) in vitro. NSCs were stimulated by rMS (200/400/600/800/1000 pulses per day, with 10 Hz frequency and 50% maximum machine output) over a 3-day period. NSCs proliferation was detected by using ki-67 and EdU staining. Ki-67, p21, p57, cyclinD1, cyclinE, cyclinA, cdk2, cdk4 proteins and miR-106b, miR-93, miR-25 mRNAs were detected by Western blotting and qRT-PCR, respectively. The results showed that rMS could promote NSCs proliferation in a dose-dependent manner. The proportions of ki-67+ and Edu+ cells in 1000 pulses group were 20.65% and 4.00%, respectively, significantly higher than those in control group (9.25%, 2.05%). The expression levels of miR-106b and miR-93 were significantly upregulated in 600-1000 pulses groups compared with control group (P<0.05 or 0.01 for all). The expression levels of p21 protein were decreased significantly in 800/1000 pulses groups, and those of cyclinD1, cyclinA, cyclinE, cdk2 and cdk4 were obviously increased after rMS as compared with control group (P<0.05 or 0.01 for all). In conclusion, our findings suggested that rMS enhances the NSCs proliferation in vitro in a dose-dependent manner and miR-106b/p21/cdks/cyclins pathway was involved in the process.

Effect of emodin on proliferation and cell cycle of human oral squamous carcinoma Tca8113 cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of emodin on proliferation and cell cycle distribution of human oral squamous carcinoma cells in vitro.</p><p><b>METHODS</b>Cultured human oral squamous carcinoma Tca8113 cells were treated with 2.5, 5, 10, 20, 40, 60 and 80 µmol/L emodin for 24, 48 or 72 h, with the cells treated with 0.1% DMSO as control. MTT assay and flow cytometry were used to evaluate the changes in cell proliferation and cell cycle distribution, respectively. Western blotting was employed to analyze the changes in the expression levels of the cell cycle-related proteins CDK2, cyclin E and P21 after emodin treatment.</p><p><b>RESULTS</b>Emodin significantly inhibited the growth and proliferation of Tca8113 cells within 72 h in a time- and dose-dependent manner, and caused cell cycle arrest in G0-G1 phase. Western blotting revealed that emodin treatment significantly lowered the expression levels of CDK2, cyclin E and P21 proteins in Tca8113 cells (P<0.05).</p><p><b>CONCLUSION</b>Emodin can inhibit the proliferation of Tca8113 cells and affect their cell cycle distribution possibly by inhibiting the signaling pathways of cell cycle regulation.</p>

Study on effect of tetramethylpyrazine on proliferation and apoptosis of leukemic U937 cells and its mechanism / 中国中药杂志

<p><b>OBJECTIVE</b>To study the proliferation and apoptosis of tetramethylpyrazine (TMP) on leukemic U937 cells and its possible mechanism.</p><p><b>METHOD</b>The inhibitory effect of TMP on the proliferation of U937 cells was detected by CCK-8 assay. The cell apoptosis and cycle distribution were examined by the flow cytometry. The mRNA expressions of bcl-2 and P27 were determined by the Real-time PCR. Western blot was carried out to detect bcl-2, caspase-3, cyclin E1, CDK2 and P27 expressions.</p><p><b>RESULT</b>TMP inhibited the proliferation of U937 cells in a dose-and-time dependent manner, with IC50 value of 160 mg x L(-1) at 48 h. In addition, TMP could induce the apoptosis of U937 cells and block the cell cycle in G0/G1 phase. According to the results of Real-time PCR and Western blot, TMP could down-regulate the expression of apoptosis-related molecule bcl-2, cycle-related protein cyclin E1 and CDK2 and up-regulate caspase-3 and P27.</p><p><b>CONCLUSION</b>TMP shows the effects in inhibiting the proliferation of leukemic U937 cells and inducing the apoptosis. Its mechanism may be related to the impacts on the cell cycle distribution, down-regulation of the bcl-2 expression, which finally activates caspase-3, starts the apoptosis path and causes the cell apoptosis.</p>

Effects of small interfering RNA silencing MACC-1 expression on cell proliferation, cell cycle and invasion ability of cervical cancer SiHa cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expression of metastasis-associated in colon cancer-1 (MACC-1) mediated by siRNA, and to study the effects of its downregulation on cell proliferation, cell cycle and invasion ability of cervical cancer SiHa cells.</p><p><b>METHODS</b>MACC-1 siRNA and control siRNA were transfected into cervical cancer SiHa cells, and the expression of MACC-1 protein after transfection with MACC-1 siRNA was detected by Western blotting. The changes of cell proliferation, cell cycle and invasion ability of the SiHa cells were determined by CCK-8 kit, flow cytometry and Boyden chamber assay. The expressions of cell cycle- and invasion-related proteins were analyzed by Western blotting.</p><p><b>RESULTS</b>Compared with the untreated group (0.317 ± 0.023) and control siRNA group (0.309 ± 0.021), the expression of MACC-1 protein was downregulated in the MACC1 siRNA group (0.041 ± 0.006) (P < 0.05), and its downregulation significantly suppressed the cell proliferation, altered the cell cycle distribution and reduced the cell invasion ability of the SiHa cells (P < 0.05). Compared with the untreated group (0.217 ± 0.025 and 0.215 ± 0.024) and the control siRNA group (0.222 ± 0.023 and 0.207 ± 0.027), the expression of cyclin D1 and Cdk2 proteins were significantly decreased in the MACC1 siRNA group (0.076 ± 0.010 and 0.039 ± 0.007) (P < 0.05). Compared with the untreated group (0.099 ± 0.007) and control siRNA group (0.105 ± 0.012), the expression of p21 protein was significantly increased in the MACC1 siRNA group (0.676 ± 0.044) (P < 0.05). The downregulation of MACC-1 expression also evoked a decrease of expressions of MMP-2 and MMP-9 proteins and an increase of E-cadherin protein expression (P < 0.05).</p><p><b>CONCLUSIONS</b>MACC-1 downregulation-mediated inhibition of proliferation and decreased invasion ability of tumor cells may be closely associated with the alterations of expressions of cell cycle- and invasion-related proteins.</p>

Inhibitions of SphK1 inhibitor SKI II on cell cycle progression and cell invasion of hepatoma HepG2 cells / 药学学报

Sphingosine kinase 1 (SphK1) plays critical roles in cell biological functions. Here we investigated the effects of SphK1 inhibitor SKI II on hepatoma HepG2 cell cycle progression and invasion. Cell survival was determined by SRB assay, cell cycle progression was assayed by flow cytometry, the ability of cell invasion was measured by Matrigel-Transwell assay and protein expression was detected by Western blotting. The results showed that SKI II markedly inhibited HepG2 cell survival in a dose-dependent manner, induced G1 phase arrest in HepG2 cell and inhibited cell invasion. SKI II markedly decreased the expressions of G1-phase-related proteins CDK2, CDK4 and Cdc2 and the levels of cell invasion-associated proteins MMP2 and MMP9. The results showed that SKI II inhibited cell cycle progression and cell invasion, implying SphK1 as a potential target for hepatoma treatment.

Effect of honokiol on proliferation and apoptosis in HL-60 cells and its potential mechanism / 中国实验血液学杂志

This study was aimed to investigate the effect of Honokiol (HNK) on proliferation and apoptosis of acute myeloid leukemia HL-60 cells and its potential mechanism. Inhibitory effect of HNK on the HL-60 cell proliferation was detected by MTT assay. Flow cytometry was used to detect the change of cell cycle and AnnexinV/PI staining was used to detect apoptosis. Western blot was applied to analyze the cell cycle protein (cyclins), cyclin-dependent kinase (CDK), P53, P21, P27, BCL-2, BCL-XL, Bax, caspase-3/9 and proteins for MAPK signal pathway. The results showed that HNK could inhibit the proliferation of HL-60 cells in time- and dose dependent ways. HNK arrested HL-60 cells in G0/G1 phase, and S phase cells decreased significantly (P < 0.05). The expression of cyclin D1, cyclin A, cyclin E and CDK2/4/6 were significantly down-regulated (P < 0.05), the expression of P53 and P21 was significantly upregulated after treating for 24 h with HNK (P < 0.05). After 24 h treatment with HNK, HL-60 cell apoptosis increased significantly with the upregulation of activated caspase-3, -9, BAX expression and the downregulation of BCL-2, BCL-XL expression. The MAPK subfamily, P38 and JNK were not significantly changed, but the expression of MEK1/2-ERK1/2 was significantly downregulated (P < 0.05). It is concluded that HNK arrestes the cells at G0/G1 phase and induces HL-60 cell apoptosis through the intervention of MEK1/2-ERK1/2 signaling pathway.

Abnormal expressions of positive cell cycle control factors and thyroid carcinoma occurrence and progression / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the relationship between abnormal expressions of positive cell cycle control factors and thyroid carcinoma occurrence and progression, and assess the value of these factors in evaluating tumor cell proliferation activity and the prognosis of the patients.</p><p><b>METHODS</b>Immunohistochemical SP method was used to detect the expressions of MCM7, CDK2 and Ki-67 proteins in 50 cases of thyroid carcinoma, 30 cases of thyroid adenoma, 30 cases of nodular goiter and 20 cases of normal thyroid gland tissues.</p><p><b>RESULTS</b>The positive rates of MCM7, CDK2 and Ki-67 expressions in thyroid carcinoma were 100% (50/50), 80.00% (40/50) and 84.00% (42/50), significantly higher than the rates in thyroid adenoma, nodular goiter and normal thyroid tissue (P<0.01). In thyroid carcinoma tissues, positive correlations were observed between the expressions of MCM7 and CDK2 proteins (r=0.637, P<0.01), MCM7 and Ki-67 proteins (r=0.633, P<0.01), and CDK2 and Ki-67 proteins (r=0.862, P<0.01).</p><p><b>CONCLUSION</b>The high expressions of MCM7, CDK2 and Ki-67 protein may contribute to the development of thyroid carcinoma, and their combined examination may serve as useful index for early diagnosis and prognostic evaluation of thyroid carcinoma. MCM7 is superior to Ki-67 in the evaluation of the thyroid tumor cell proliferation activity.</p>

Blocking effect of arsenic trioxide on the proliferation and cell cycle of human Burkitt lymphoma cells and its related mechanism / 中国实验血液学杂志

This study was aimed to investigate the effect of arsenic trioxide (As2O3) on proliferation and cell cycle of human Burkitt lymphoma cells and its related molecular mechanism, so as to provide experimental evidence for treatment of Burkitt lymphoma with As2O3. Human Burkitt lymphoma cell line Namalwa was used as the model, the effect of As2O3 on cell proliferation, cell cycle and apoptosis, as well as the expression of cell cycle modulation related genes, including mRNA and protein level, were detected by MTT method, flow cytometry, real-time quantitative PCR (RQ-PCR) and Western blot, respectively. The results showed that the As2O3 inhibited significantly the growth and proliferation of Namalwa cells in concentration-and time-dependent manner. The As2O3 arrested obviously cell cycle of Namalwa cells in G1 phase, and showed significant concentration-effect relationship. The As2O3 induced the apoptosis of Namalwa cells in concentration-and time-dependent manner, downregulated the expression of the important driving genes of cell cycle including Cyclin E and CDK2 in mRNA and protein level, upregulated the expression of the important inhibiting gene of cell cycle-P21 in mRNA and protein level in concentration-dependent manner. It is concluded that As2O3 inhibits significantly the growth and proliferation of Namalwa cells, and the effect was closely relates with its inducing the apoptosis and blocking the cell cycle of Namalwa. The action of blocking cell cycle is closely associated with its downregulating the expression of driving genes of cell cycle-Cyclin E and CDK2, upregulating the expression of the inhibiting gene of cell cycle-P21.

Effect of Oxaliplatin on cell cycle of hepatocellular carcinoma cell line HepG2 / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of Oxaliplatin (L-OHP) on cell cycle in hepatocellular carcinoma cell line HepG2 and the involved mechanism.</p><p><b>METHODS</b>Inhibitory effect of L-OHP on the proliferation of HepG2 cells was determined by MTT assay. Cell cycle distribution was shown by flow FCM. The expression levels of cyclinD1, CDK2, CDK4, p16, p21, p53 were detected by RT-PCR and Western blot.</p><p><b>RESULTS</b>MTT method revealed that L-OHP inhibited proliferation of hepatocellular carcinoma HepG2 cells in a dose- and time-dependent manner. L-OHP induced S cell cycle arrest in HepG2 cell; down-regulated the levels of CDK4, cyclinD1 and up-regulated the levels of p21, p53. There were no significant changes of CDK2 and p16 after L-OHP treatment.</p><p><b>CONCLUSION</b>L-OHP inhibits the proliferation of HepG2 cells by blocking cell at S stage, which may be resulted from the activity of CDK4, CyclinD1 and p21.</p>

Effect of silencing AEG-1 with small interfering RNA on the proliferation and cell cycle of gastric carcinoma SGC-7901 cells / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the effect of down-regulation of astrocyte elevated gene-1 (AEG-1) expression on cell proliferation and cell cycle of gastric carcinoma cells, and its possible molecular mechanism.</p><p><b>METHODS</b>Control siRNA and AEG-1 siRNA were transfected into gastric carcinoma SGC-7901 cells. 48 h after transfection, the cells were divided into 3 groups including untransfected, siRNA control and AEG-1 siRNA transfection groups. Expressions of AEG-1 mRNA and protein in the 3 group cells were detected by real-time quantitative PCR and Western blot. The changes of cell proliferation were examined using CCK-8 kit, and the cell cycle distribution was detected by flow cytometry. Finally, expressions of cell proliferation and cell cycle related proteins were detected by Western blot.</p><p><b>RESULTS</b>Real-time quantitative PCR and Western blot demonstrated that compared with the untransfected and siRNA control groups, expressions of AEG-1 mRNA and protein were significantly down-regulated in the AEG-1 siRNA transfection group (P < 0.05), but there was no significant difference between the untransfected and siRNA control groups (P > 0.05). Furthermore, in vivo experiment confirmed a significant down-regulation of AEG-1 protein in the AEG-1 siRNA transfection group (P < 0.05). In addition, AEG-1 siRNA obviously inhibited the proliferation of SGC-7901 cells at different time points after transfection with AEG-1 siRNA. The percentage of cells in G0/G1 phase in the AEG-1 siRNA transfection group [(61.26 ± 1.25)%] was significantly higher than those in the untransfected group [(46.17 ± 1.91)%] and siRNA control group [(46.46 ± 1.96)%], and there was a significant difference between them (all P < 0.001). Furthermore, the result of Western blotting revealed that down-regulation of AEG-1 expression evoked the down-regulation of cdk2 and cyclin D1 expressions and elevation of p21 expression in vitro and in vivo.</p><p><b>CONCLUSIONS</b>The inhibition of cell proliferation and cell cycle arrest mediated by down-regulation of AEG-1 expression may be closely associated with the changes of expression of cell cycle related proteins including cdk2, cyclin D1 and p21.</p>

Structure of the catalytic domain of a state transition kinase homolog from Micromonas algae

Under natural environments, plants and algae have evolved various photosynthetic acclimation mechanisms in response to the constantly changing light conditions. The state transition and long-term response processes in photosynthetic acclimation involve remodeling and composition alteration of thylakoid membrane. A chloroplast protein kinase named Stt7/STN7 has been found to have pivotal roles in both state transition and long-term response. Here we report the crystal structures of the kinase domain of a putative Stt7/STN7 homolog from Micromonas sp. RCC299 (MsStt7d) in the apo form and in complex with various nucleotide substrates. MsStt7d adopts a canonical protein kinase fold and contains all the essential residues at the active site. A novel hairpin motif, found to be a conserved feature of the Stt7/STN7 family and indispensable for the kinase stability, interacts with the activation loop and fixes it in an active conformation. We have also demonstrated that MsStt7d is a dualspecifi city kinase that phosphorylates both Thr and Tyr residues. Moreover, preliminary in vitro data suggest that it might be capable of phosphorylating a consensus N-terminal pentapeptide of light-harvesting proteins Micromonas Lhcp4 and Arabidopsis Lhcb1 directly. The potential peptide/protein substrate binding site is predicted based on the location of a pseudo-substrate contributed by the adjacent molecule within the crystallographic dimer. The structural and biochemical data presented here provide a framework for an improved understanding on the role of Stt7/STN7 in photosynthetic acclimation.

Effect of down-regulation of histone deacetylase 2 protein expression on cell proliferation and cell cycle in cervical carcinoma / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the effect of down-regulation of histone deacetylase 2 (HDAC2) expression on cell proliferation and cell cycle in cervical carcinoma cell lines HeLa.</p><p><b>METHODS</b>HDAC2 siRNA and control siRNA were transfected to HeLa cells. CCK-8 and flow cytometry were used to analyze the changes of cell proliferation and cell cycle, respectively. Western blot was employed to detect the changes of cell proliferation and cell cycle-related proteins.</p><p><b>RESULTS</b>HDAC2 siRNA significantly down-regulated the expression of HDAC2 protein in HeLa cells, resulting in marked inhibition of cell proliferation. In addition, the percentage of cells in G(0)/G(1) phase in HDAC2 siRNA group (63.3% ± 2.0%) was significantly higher than that in untreated group (29.3% ± 1.7%) or control siRNA group (29.4% ± 1.7%), F = 354.181, P = 0.000. Furthermore, Western blot demonstrated that down-regulation of HDAC2 expression decreased the expression of cyclin D1, cyclin E and CDK2 proteins but increased the expression of p21 protein.</p><p><b>CONCLUSIONS</b>Down-regulation of HDAC2 expression mediates proliferation inhibition and cell cycle arrest. It is associated with decrease in cyclin D1, cyclin E and CDK2 protein expression and increase in p21 protein expression.</p>

Effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration of laryngeal squamous cell carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression of histone deacetylase 6 (HDAC6) in laryngeal squamous cell carcinoma, and to analyze the effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration of laryngeal squamous cell carcinoma cell line Hep-2 cells, and to explore their possible molecular mechanisms.</p><p><b>METHODS</b>Immunohistochemistry was used to detect the expression of HDAC6 protein in 55 cases of laryngeal squamous cell carcinoma and 20 cases of normal laryngeal mucosa. HDAC6 siRNA and control siRNA were transfected into Hep-2 cells via lipofectamine 2000, and the interfering effect was analyzed using Western blotting. The effects of downregulation of HDAC6 expression on cell cycle, proliferation and migration were determined by cell counting kit-8 (CCK-8), flow cytometry and Boyden chamber, respectively. Finally, Western blotting was used to detect the expressions of cell cycle, proliferation and migration related proteins.</p><p><b>RESULTS</b>There was a high level expression of HDAC6 protein in laryngeal squamous cell carcinoma, and its expression was not related to age and sex of the patients (P > 0.05), but closely associated with the degree of histological differentiation, TNM staging and lymph node metastasis (P < 0.05). HDAC6 siRNA effectively down-regulated the expression of HDAC6 protein in laryngeal squamous cell carcinoma cell line Hep-2 cells, and downregulation of its expression obviously inhibited cell proliferation, arrested cell cycle at G(0)/G(1) phase and decreased cell migration ability in Hep-2 cells. Additionally, the downregulation of HDAC6 protein expression markedly decreased the expressions of cyclin D1, cyclin E, cdk2 and MMP-9 proteins, but increased the expressions of p21 and E-cadherin proteins.</p><p><b>CONCLUSIONS</b>HDAC6 may play a pivotal role in the carcinogenesis and development of laryngeal squamous cell carcinoma. The downregulation of HDAC6 expression-mediated cell proliferation inhibition, cell cycle arrest and decreased cell migration ability may be closely associated with the decrease of cyclin D1, cyclin E, cdk2 and MMP-9 proteins and increase of p21 and E-cadherin proteins.</p>

Effect of Notch1 on cell cycle, apoptosis and migration of laryngeal squamous cell carninoma cell line Hep-2 / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the effect of Notch1 on cell cycle, apoptosis and migration of laryngeal squamous cell carcinoma cell line Hep-2 and explore its possible molecular mechanism.</p><p><b>METHODS</b>Hep-2 cells were divided into three groups: untreated group, empty vector group and Notch1 group. The effects of upregulation of Notch1 expression on cell proliferation, cell cycle and apoptosis were assessed by CCK-8 staining and flow cytometry, respectively, and effect of upregulation of Notch1 expression on cell migration of Hep-2 cells was studied using Boyden chamber assay, and further expression changes of genes related to cell proliferation, cell cycle, apoptosis and migration were detected by semi-quantitative RT-PCR and Western blotting.</p><p><b>RESULTS</b>Compared with the untreated group and empty vector group, cell proliferation of Hep-2 in the Notch1 group was significantly inhibited (P < 0.05). The results of flow cytometry revealed that the percentage of cells at G0/G1 phase in the Notch1 group was (70.43 +/- 1.36)%, significantly higher than the (46.39 +/- 1.19)% in the untreated group or (48.41 +/- 1.18)% in the empty vector group, and there was a significant difference among the three groups (P = 0.000). In addition, the percentage of apoptotic cells in the Notch1 group was (22.46 +/- 0.90)%, significantly higher than that in the untreated group [(5.77 +/- 0.37)%] or empty vector group [(6.09 +/- 0.20)%], with a significant difference among the three groups (P = 0.000). The results of Boyden chamber assay demonstrated that the number of cells migrated through membrane in the Notch1 group was evidently lower than that in the untreated group and empty vector group. Moreover, the results of semi-quantitative RT-PCR and Western blotting showed that cell proliferation inhibition and cell cycle arrest were closely associated with downregulation of cyclin D1, cyclin E and CDK2 expressions and upregulation of p53 expression. In addition, upregulation of Notch1 expression mediated cell apoptosis was tightly related to upregulation of caspase 3/9 expressions and downregulation of Bcl-2, while the decrease of Hep-2 cell migration ability was obviously correlated with downregulation of MMP-2/-9 expressions.</p><p><b>CONCLUSIONS</b>Notch1 signaling pathway may play a pivotal role in the occurrence and development of laryngeal squamous cell carcinoma. Further study may elucidate that Notchl signaling pathway may become a molecular target for therapy of laryngeal squamous cell carcinoma.</p>

Effects of Qufengtongluo Recipe on expressions of cell cycle regulatory proteins in rat mesangial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effects of Qufengtongluo Recipe (QFTLR) on the expressions of cell cycle regulatory proteins in rat mesangial cells (MCs) in vitro and investigate the mechanism by which QFTLR inhibits MC proliferation.</p><p><b>METHODS</b>Using the methods of serum pharmacology, we studied the expressions of cell cycle regulatory proteins in rat MCs treated with QFTLR by laser scanning confocal microscope and immunohistochemistry.</p><p><b>RESULTS</b>Compared with the normal control cells, the cells challenged with lipopolysaccharide (LPS) showed significantly enhanced expressions of cyclin D1, CDK2, and P21 (P<0.01) and obviously lowered protein expression of P27 (P<0.01). Treatment of the LPS-challenged cells with QFTLR and benazepril both resulted in significantly attenuated expressions of cyclin D1, CDK2, and P21 and obvious increase of P27 expression (P<0.05 or P<0.01), but QFTLR produced stronger effects than benazepril in regulating of cyclinD1, P21 and P27 protein expressions (P<0.05 or P<0.01).</p><p><b>CONCLUSION</b>QFTLR inhibits rat MC proliferation in vitro possibly by down-regulating the cellular expressions of cyclin D1, CDK2, and P21 and up-regulating the expression of P27 protein.</p>

NNIspm, a polyamine derivative, induces cellular senescence of human hepatoma HepG2 cells and its molecular mechanism / 药学学报

This study is to examine the effects of NNIspm-mediated cellular senescence of HepG2 cells and elucidate its potential molecular mechanism. Cellular senescence was detected with senescence-associated beta-galactosidase staining. Cell cycle distribution, intracellular fluorescence intensity and accumulation of intracellular reactive oxygen species (ROS) were detected by high content screening (HCS). Protein expression was detected by Western blotting. Polyamines content was analyzed by high performance liquid chromatography (HPLC). The results demonstrated that NNIspm significantly induced HepG2 cells senescence. This effect was due to the decrease of intracellular polyamines, the arrest at G0/G1 phase and an increase of ROS level. The molecular senescence marker p21 increased significantly after NNIspm treatment. In contrast, the protein expressions of Cyclin E and CDK2 were obvious down-regulation. The results indicated that cellular senescence induced by NNIspm was one of its antitumor mechanisms.