OBJECTIVE: To investigate the effects of mTOR inhibitors everolimus (EVE) and gemcitabine (GEM) on the proliferation, apoptosis and cell cycle of diffuse large B-cell lymphoma (DLBCL) cell line U2932, and further explore the molecular mechanisms, so as to provide new ideas and experimental basis for the clinical treatment of DLBCL. METHODS: The effect of EVE and GEM on the proliferation of U2932 cells was detected by CCK-8 assay, the IC₅₀ of the two drugs was calculated, and the combination index (CI=) of the two drugs was calculated by CompuSyn software. The effect of EVE and GEM on apoptosis of U2932 cells was detected by flow cytometry with AnnexinV-FITC/PI staining. Flow cytometry with propidium iodide (PI) staining was used to detect the effect of EVE and GEM on the cell cycle of U2932 cells. Western blot assay was used to detect the effects of EVE and GEM on the channel proteins p-mTOR and p-4EBP1, the anti-apoptotic proteins MCL-1 and Survivin, and the cell cycle protein Cyclin D1. RESULTS: Both EVE and GEM could significantly inhitbit the proliferation of U2932 cells in a time- and dose-dependent manner (r=0.465, 0.848; 0.555, 0.796). According to the calculation of CompuSyn software, EVE combined with GEM inhibited the proliferation of U2932 cells at 24, 48 and 72 h with CI=<1, which had a synergistic effect. After treated U2932 cells with 10 nmol/L EVE, 250 nmol/L GEM alone and in combination for 48 h, both EVE and GEM induced apoptosis, and the difference was statistically significant compared with the control group (P<0.05). The apoptosis rate was significantly enhanced after EVE in combination with GEM compared with single-agent (P<0.05). Both EVE and GEM alone and in combination significantly increased the proportion of cells in G₁ phase compared with the control group (P<0.05). The proportion of cells in G₁ phase was significantly increased when the two drugs were combined (P<0.05). The expression of p-mTOR and effector protein p-4EBP1 was significantly downregulated in the EVE combined with GEM group, the expression of anti-apoptotic proteins MCL-1, Survivin and cell cycle protein cyclin D1 was downregulated too (P<0.05). CONCLUSION EVE combined with GEM can synergistically inhibit the proliferation of U2932 cells, and the mechanism may be that they can synergistically induce apoptosis by downregulating the expression of MCL-1 and Survivin proteins and block the cell cycle progression by downregulating the expression of Cyclin D1.
Humans ; Gemcitabine ; Everolimus/pharmacology* ; Survivin/pharmacology* ; Cyclin D1/pharmacology* ; Myeloid Cell Leukemia Sequence 1 Protein ; Cell Line, Tumor ; Cell Proliferation ; TOR Serine-Threonine Kinases ; Apoptosis ; Apoptosis Regulatory Proteins ; Cell Cycle Proteins ; Lymphoma, Large B-Cell, Diffuse

Bavachin is a dihydroflavonoid compound isolated from Psoralea corylifolia, and exhibits anti-bacterial, anti-inflammatory, anti-tumor and lipid-lowering activities. Recent attention has gradually drawn on bavachin-induced apoptosis in many human cancer cell lines. However, the anti-cancer effects and related mechanisms in colorectal cancer remain unknown. Here, we investigated the effects of bavachin on colorectal cancer in vivo and in vitro. The results showed that bavachin inhibited the proliferation of human colorectal cancer cells and induce apoptosis. These changes were mediated by activating the MAPK signaling pathway, which significantly up-regulated the expression of Gadd45a. Furthermore, Gadd45a silencing obviously attenuated bavachin-mediated cell apoptosis. Inhibition of the MAPK signaling pathway by JNK/ERK/p38 inhibitors also weakened the up-regulation of Gadd45a by bavachin. The anticancer effect of bavachin was also validated using a mouse xenograft model of human colorectal cancer. In conclusion, these findings suggest that bavachin induces the apoptosis of colorectal cancer cells through activating the MAPK signaling pathway.
Humans ; Signal Transduction ; Flavonoids/pharmacology* ; Proteins/pharmacology* ; MAP Kinase Signaling System ; Colorectal Neoplasms/metabolism* ; Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Cell Cycle Proteins/pharmacology*

OBJECTIVE: To investigate the effects of methionine restriction on proliferation, cell cycle and apoptosis of human acute leukemia cells. METHODS: Cell Counting Kit-8 (CCK-8) assay was used to detect the effect of methionine restriction on HL-60 and Jurkat cells proliferation. The effect of methionine restriction on cell cycle of HL-60 and Jurkat cells was examined by PI staining. Annexin V-FITC / PI double staining was applied to detect apoptosis of HL-60 and Jurkat cells following methionine restriction. The expression of cell cycle-related proteins cyclin B1, CDC2 and apoptosis-related protein Bcl-2 was evaluated by Western blot assay. RESULTS: Methionine restriction significantly inhibited the proliferation of HL-60 and Jurkat cells in a time-dependent manner (HL-60: r =0.7773, Jurkat: r =0.8725), arrested the cells at G2/M phase (P < 0.001), and significantly induced apoptosis of HL-60 and Jurkat cells (HL-60: P < 0.001; Jurkat: P < 0.05). Furthermore, Western blot analysis demonstrated that methionine restriction significantly reduced the proteins expression of Cyclin B1 (P < 0.05), CDC2 (P < 0.01) and Bcl-2 (P < 0.001) in HL-60 and Jurkat cells. CONCLUSION Acute leukemia cells HL-60 and Jurkat exhibit methionine dependence. Methionine restriction can significantly inhibit the proliferation, promote cell cycle arrest and induce apoptosis of HL-60 and Jurkat cells, which suggests that methionine restriction may be a potential therapeutic strategy for acute leukemia.
Humans ; Cyclin B1/pharmacology* ; Cell Proliferation ; Methionine/pharmacology* ; Cell Cycle ; Apoptosis ; Leukemia, Myeloid, Acute ; Cell Division ; Cell Cycle Proteins ; Jurkat Cells ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; HL-60 Cells

OBJECTIVE: To investigate the effects of curcumin on the proliferation, apoptosis, and cell cycle of human acute myeloid leukemia cell line K562. METHODS: MTT method was used to detect the proliferation inhibition of logarithmic growth phase human acute myeloid leukemia K562 cells, flow cytometry was used to detect the cell cycle, Annexin V-FITC was used to detect the apoptosis rate, and real-time fluorescent quantitative PCR and Western blot were used to detect the expression of Bax, BCL-2 and caspase-3 mRNA and protein, respectively. RESULTS: The inhibition rate of cell proliferation in curcumin 10, 20, and 40 μmol/L group for 24 h and 48 h were higher than that in the control group (curcumin 0 μmol/L), and the cell proliferation inhibition rate was concentration-time dependent (r=0.879, r=0.914). The proportion of G₀/G₁ cells and apoptosis rate of K562 cells in the curcumin 10, 20, and 40 μmol/L group were higher than those in the control group, and showed drug concentration dependent (r=0.856, r=0.782). The expression of Bax and Caspase-3 mRNA in the curcumin 10, 20, and 40 μmol/L group was higher, while BCL-2 mRNA was lower than those in the control group, and showed drug concentration dependent (r=0.861, r=0.748, r=-0.817). The gray value of Bax protein expression in the curcumin 10, 20, and 40 μmol/L group was higher than that in the control group, while the gray value of BCL-2 and Caspase-3 protein expression was lower than that in the control group, and showed drug concentration dependent (r=0.764, r=-0.723, r=-0.831). CONCLUSION Curcumin can inhibit the proliferation of human acute myeloid leukemia cell line K562 cells, block the cell cycle at G₀/G₁ phase, promote cell apoptosis, and induce apoptosis by regulating Bax, BCL-2, and Caspase-3.
Apoptosis ; Caspase 3/metabolism* ; Cell Cycle ; Cell Proliferation ; Curcumin/pharmacology* ; Humans ; K562 Cells ; Leukemia, Myeloid, Acute/genetics* ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; RNA, Messenger/metabolism* ; bcl-2-Associated X Protein/pharmacology*

Currently, chemoresistance seriously attenuates the curative outcome of liver cancer. The purpose of our work was to investigate the influence of 6-shogaol on the inhibition of 5-fluorouracil (5-FU) in liver cancer. The cell viability of cancer cells was determined by MTT assay. Liver cancer cell apoptosis and the cell cycle were examined utilizing flow cytometry. Moreover, qRT-PCR and western blotting was used to analyse the mRNA and protein expression levels, respectively. Immunohistochemistry assays were used to examine multidrug resistance protein 1 (MRP1) expression in tumour tissues. In liver cancer cells, we found that 6-shogaol-5-FU combination treatment inhibited cell viability, facilitated G0/G1 cell cycle arrest, and accelerated apoptosis compared with 6-shogaol or 5-FU treatment alone. In cancer cells cotreated with 6-shogaol and 5-FU, AKT/mTOR pathway- and cell cycle-related protein expression levels were inhibited, and MRP1 expression was downregulated. AKT activation or MRP1 increase reversed the influence of combination treatment on liver cancer cell viability, apoptosis and cell cycle arrest. The inhibition of AKT activation to the anticancer effect of 6-shogaol-5-FU could be reversed by MRP1 silencing. Moreover, our results showed that 6-shogaol-5-FU combination treatment notably inhibited tumour growth in vivo. In summary, our data demonstrated that 6-shogaol contributed to the curative outcome of 5-FU in liver cancer by inhibiting the AKT/mTOR/MRP1 signalling pathway.
ATP Binding Cassette Transporter, Subfamily B, Member 1 ; Apoptosis ; Catechols ; Cell Cycle ; Cell Cycle Checkpoints ; Cell Line, Tumor ; Cell Proliferation ; Drug Resistance, Neoplasm ; Fluorouracil/pharmacology* ; Humans ; Liver Neoplasms/genetics* ; Multidrug Resistance-Associated Proteins ; Proto-Oncogene Proteins c-akt/metabolism* ; TOR Serine-Threonine Kinases/metabolism*

Cell Cycle/drug effects* ; Cell Line, Tumor ; Chalcone/pharmacology* ; Humans ; Membrane Potential, Mitochondrial/drug effects* ; Neuronal Outgrowth/drug effects* ; Okadaic Acid/toxicity* ; Reactive Oxygen Species/metabolism* ; Tretinoin/pharmacology* ; tau Proteins/metabolism*

Polo-like kinase 1 (Plk1) is widely regarded as one of the most promising targets for cancer therapy due to its essential role in cell division and tumor cell survival. At present, most Plk1 inhibitors have been developed based on kinase domain, some of which are in clinical trial. However, inhibitors targeting kinase domain face off-target effect and drug resistance owing to the conserved nature and the frequent mutations in the ATP-binding pocket. In addition to a highly conserved kinase domain, Plk1 also contains a unique Polo-Box domain (PBD), which is essential for Plk1's subcellular localization and mitotic functions. Inhibitors targeting Plk1 PBD show stronger selectivity and less drug resistance for cancer therapy. Therefore, Plk1 PBD is an attractive target for the development of anti-cancer agents. In this review, we will summarize the up-to date drug discovery for targeting Plk1 PBD, including the molecular structure and cellular functions of Plk1 PBD. Small-molecule inhibitors targeting Plk1 PBD not only provide an opportunity to specifically inhibit Plk1 activity for cancer treatment, but also unveil novel biological basis regarding the molecular recognition of Plk1 and its substrates.
Cell Cycle Proteins/genetics* ; Neoplasms/drug therapy* ; Protein Kinase Inhibitors/pharmacology* ; Protein-Serine-Threonine Kinases/genetics* ; Proto-Oncogene Proteins/genetics*

Proteasome inhibitors have shown remarkable success in the treatment of hematologic neoplasm. There has been a lot of attention to applying these drugs for solid tumor treatment. Recent preclinical study has signified the effectiveness on cell proliferation inhibition in lung adenocarcinoma treated by carfilzomib (CFZ), a second generation proteasome inhibitor. However, no insight has been gained regarding the mechanism. In this study, we have systematically investigated the CFZ functions in cell proliferation and growth, cell cycle arrest, and apoptosis in lung adenocarcinoma cells. Flow cytometry experiments showed that CFZ significantly induced G2/M cell cycle arrest and apoptosis in lung adenocarcinoma. MTS and colony formation assays revealed that CFZ substantially inhibited survival of lung adenocarcinoma cells. All results were consistently correlated to the upregulation expression of Gadd45a, which is an important gene in modulating cell cycle arrest and apoptosis in response to physiologic and environmental stresses. Here, upregulation of Gadd45a expression was observed after CFZ treatment. Knocking down Gadd45a expression suppressed G2/M arrest and apoptosis in CFZ-treated cells, and reduced cytotoxicity of this drug. The protein expression analysis has further identified that the AKT/FOXO3a pathway is involved in Gadd45a upregulation after CFZ treatment. These findings unveil a novel mechanism of proteasome inhibitor in anti-solid tumor activity, and shed light on novel preferable therapeutic strategy for lung adenocarcinoma. We believe that Gadd45a expression can be a highly promising candidate predictor in evaluating the efficacy of proteasome inhibitors in solid tumor therapy.
Adenocarcinoma of Lung/pathology* ; Apoptosis/drug effects* ; Cell Cycle Checkpoints/drug effects* ; Cell Cycle Proteins/genetics* ; Cell Line, Tumor ; Forkhead Box Protein O3/physiology* ; Gene Expression Regulation, Neoplastic/drug effects* ; Humans ; Lung Neoplasms/pathology* ; Oligopeptides/pharmacology* ; Proto-Oncogene Proteins c-akt/physiology* ; Up-Regulation

OBJECTIVE: To investigate the interaction between interleukin-17 (IL-17) and interferon-γ (IFN-γ) and how their interaction affects the growth of mouse hepatoma Hepa1-6 cells. METHODS: Hepa1-6 cells treated with IL-17 and IFN-γ either alone or in combination were examined for changes in cell proliferation using MTT assay and in cell cycle distribution using flow cytometry. Western blotting was used to detect the protein expression levels of proliferating cell nuclear antigen (PCNA), cyclin D1, P21 and P16 and the phosphorylation of p38MAPK, ERK1/2 and Stat1 in the cells. RESULTS: Compared with control group, IFN-γ treatment obviously inhibited the growth and proliferation of Hepa1-6 cells, induced cell cycle arrest at G0/G1 phase, reduced the protein expression of PCNA and cyclin D1, and increased the protein expression of P21. IL-17 alone had no effect on the growth of Hepa1-6 cells. In the combined treatment, IL-17 significantly antagonized the effects of IFN-γ. Compared with those treated with IFN-γ alone, the cells with the combined treatment showed significantly decreased G0/G1 cell population, increased the protein expressions of PCNA and cyclin D1, and decreased the protein expression of P21. IL-17 significantly inhibited IFN-γ-induced phosphorylation of p38MAPK and ERK1/2 without affecting the phosphorylation of Stat1. CONCLUSIONS IL-17 obviously reverses the antitumor effects of IFN-γ to promote the proliferation of mouse hepatoma cells and accelerate the development of hepatocellular carcinoma.
Animals ; Carcinoma, Hepatocellular ; metabolism ; pathology ; Cell Cycle ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Interferon-gamma ; antagonists & inhibitors ; Interleukin-17 ; pharmacology ; Liver Neoplasms ; metabolism ; pathology ; Mice ; Neoplasm Proteins ; metabolism ; Proliferating Cell Nuclear Antigen ; metabolism

Interferon-γ (IFN-γ) has been used to control cancers in clinical treatment. However, an increasing number of reports have suggested that in some cases effectiveness declines after a long treatment period, the reason being unclear. We have reported previously that long-term IFN-γ treatment induces malignant transformation of healthy lactating bovine mammary epithelial cells (BMECs) in vitro. In this study, we investigated the mechanisms underlying the malignant proliferation of BMECs under IFN-γ treatment. The primary BMECs used in this study were stimulated by IFN-γ (10 ng/mL) for a long term to promote malignancy. We observed that IFN-γ could promote malignant cell proliferation, increase the expression of cyclin D1/cyclin-dependent kinase 4 (CDK4), decrease the expression of p21, and upregulate the expression of cellular-abelsongene (c-Abl) and histone deacetylase 2 (HDAC2). The HDAC2 inhibitor, valproate (VPA) and the c-Abl inhibitor, imatinib, lowered the expression level of cyclin D1/CDK4, and increased the expression level of p21, leading to an inhibitory effect on IFN-γ-induced malignant cell growth. When c-Abl was downregulated, the HDAC2 level was also decreased by promoted proteasome degradation. These data suggest that IFN-γ promotes the growth of malignant BMECs through the c-Abl/HDAC2 signaling pathway. Our findings suggest that long-term application of IFN-γ may be closely associated with the promotion of cell growth and even the carcinogenesis of breast cancer.
Animals ; Carcinogenesis/pathology* ; Cattle ; Cell Cycle Proteins/metabolism* ; Cell Proliferation/drug effects* ; Cell Transformation, Neoplastic/pathology* ; Cells, Cultured ; Epithelial Cells/pathology* ; Female ; Histone Deacetylase 2/metabolism* ; Imatinib Mesylate/pharmacology* ; Interferon-gamma/pharmacology* ; Mammary Glands, Animal/pathology* ; Mammary Neoplasms, Experimental/pathology* ; Proto-Oncogene Proteins c-abl/metabolism* ; Signal Transduction ; Valproic Acid/pharmacology*