A natural phenylpropionate derivative from Mirabilis himalaica inhibits cell proliferation and induces apoptosis in HepG2 cells

Bioactivity-guided study led to the isolation of a natural phenylpropionate derivative, (E)-3-(4-hydroxy-2-methoxyphenyl)-propenoic acid 4-hydroxy-3-methoxyphenyl ester from the roots of Mirabilis himalaica. Cellular analysis showed that compound 1 specifically inhibited the cancer cell growth through the S phase arrest. Mechanistically, compound 1 was able to induce the apoptosis in HepG2 cells through mitochondrial apoptosis pathway in which Bcl-2 and p53 were required. Interestingly, the cellular phenotype of compound 1 were shown specifically in cancer cells originated from hepatocellular carcinoma (HepG2) while compromised influence by compound 1 were detected within the normal human liver cells (L-02). Consistently, the in vivo inhibitory effects of compound 1 on tumor growth were validated by the in xenograft administrated with HepG2 cells. Our results provided a novel compound which might serve as a promising candidate and shed light on the therapy of the hepatocellular carcinoma.     

Shikonin inhibits proliferation of melanoma cells by MAPK pathway-mediated induction of apoptosis

Shikonin, a natural product isolated from the roots of Lithospermum erythrorhizon, exhibits pharmacological effects against inflammation, ulcers, infections, and tumors. In the present study, we aimed to investigate the antitumor effects of shikonin on the human melanoma cell line, A375SM, and in an in vivo mouse xenograft model. We examined the anticancer effects of shikonin by in vitro experiments (MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, 4′,6-diamidino-2-phenylindole (DAPI) stain, annexin V/ propidium iodide (PI) stain, and protein analysis of apoptosis and mitogen-activated protein kinase (MAPK) pathways). Further, the anticancer effect in vivo was confirmed through a xenograft model. Our results showed that shikonin inhibited the proliferation of melanoma cells in a dose-dependent manner. In addition, shikonin significantly increased nucleus and chromatin condensation and early/late apoptosis. Shikonin also increased the pro-apoptotic proteins and decreased the anti-apoptotic proteins. Additionally, shikonin was overexpressed in MAPK pathways. Investigation of the effects of shikonin in a mouse xenograft model not only showed decreased A375SM tumor volume but also increased apoptosis as determined by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay. Furthermore, pathologic changes were not observed in the liver and kidney of mice. Collectively, the study indicated that shikonin inhibited the proliferation of the human melanoma cells by inducing apoptosis, mediated by MAPK pathway and that it is a potential candidate for an anticancer drug against melanoma cancer.     

Panaxydol inhibits the proliferation and induces the differentiation of human hepatocarcinoma cell line HepG2

Panaxydol, a polyacetylene compound isolated from Panax ginseng, exerts anti-proliferative effects against malignant cells. No previous study, however, has been reported on its effects on hepatocellular carcinoma cells. Here, we investigated the effects of panaxydol on the proliferation and differentiation of human hepatocarcinoma cell line HepG2. We studied by electronic microscopy of morphological and ultrastructural changes induced by panaxydol. We also examined the cytotoxicities of panaxydol against HepG2 cells using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl tetrazolium bromide assay and the effect of panaxydol on cell cycle distributions by flow cytometry. We investigated the production of liver proteins in panaxydol-treated cells including alpha-fetoprotein and albumin and measured the specific activity of alkaline phosphatase and gamma-glutamyl transferase. We further investigated the effects of panaxydol on the expression of Id-1, Id-2, p21 and pRb by RT-PCR or immunoblotting analysis. We found that panaxydol inhibited the proliferation of HepG2 cells and caused morphological and ultrastructural changes in HepG2 cells resembling more mature forms of hepatocytes. Moreover, panaxydol induced a cell cycle arrest at the G₁ to S transition in HepG2 cells. It also significantly decreased the secretion of alpha-fetoprotein and the activity of gamma-glutamyl transferase. By contrast, panaxydol remarkably increased the secretion of albumin and the alkaline phosphatase activity. Furthermore, panaxydol increased the mRNA content of p21 while reducing that of Id-1 and Id-2. Panaxydol also increased the protein levels of p21, pRb and the hypophosphorylated pRb in a dose-dependent manner. These findings suggest that panaxydol is of value for further exploration as a potential anti-cancer agent.     

NK4 inhibits the proliferation and induces apoptosis of human rheumatoid arthritis synovial cells

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by proliferation and insufficient apoptosis of synovial cells. NK4 is a hepatocyte growth factor antagonist and is implicated in cell proliferation, viability, and apoptosis of many tumour cells. This study aimed to investigate the role of NK4 in the regulation of human RA synovial cell proliferation and apoptosis. Fibroblast‐like synoviocytes (FLSs) isolated from RA patients and MH7A synovial cells were subjected to MTT, flow cytometry, and Western blot analysis. We found that NK4 suppressed cell proliferation through cell cycle arrest at the G0/G1 phase and induced apoptosis in RA synovial cells. Furthermore, NK4 altered the expression of cell cycle and apoptosis‐related proteins such as cyclin D1, cyclin B1, PCNA, p21, p53, Bcl‐2, Bax, cleaved caspase‐9, and cleaved caspase‐3. Additionally, NK4 reduced the phosphorylation level of NF‐κB p65 and upregulated the expression of sirt1, but did not change the levels of p38 and p‐p38 in RA‐FLS and MH7A cells. In conclusion, NK4 inhibits the proliferation and induces apoptosis of human RA synovial cells. NK4 is a promising therapeutic target for RA. We demonstrated that NK4 inhibited cell proliferation by inducing apoptosis and arresting cell cycle in RA‐FLS and MH7A cells. The apoptotic effects of NK4 may be mediated in part by decreasing Bcl‐2 protein level, increasing Bax and caspase 3 protein levels, and inhibiting NF‐κB signalling in RA‐FLS and MH7A cells. These findings reveal potential mechanism underlying the role of NK4 in RA synovial cells and suggest that NK4 is a promising agent for RA treatment.     

Knockdown of Rab21 inhibits proliferation and induces apoptosis in human glioma cells

Background

Gliomas are commonly malignant tumors that arise in the human central nervous system and have a low overall five-year survival rate. Previous studies reported that several members of Rab GTPase family are involved in the development of glioma, and abnormal expression of Rab small GTPases is known to cause aberrant tumor cell behavior. In this study, we characterized the roles of Rab21 (Rab GTPase 21), a member of Rab GTPase family, in glioma cells.

Methods

The study involved downregulation of Rab21 in two glioma cell lines (T98G and U87) through transfection with specific-siRNA. Experiments using the MTT assay, cell cycle analysis, apoptosis assay, real-time PCR and western blot were performed to establish the expression levels of related genes.

Results

The results show that downregulation of Rab21 can significantly inhibit cell growth and remarkably induce cell apoptosis in T98G and U87 cell lines. Silencing Rab21 resulted in significantly increased expression of apoptosis-related proteins (caspase7, Bim and Bax) in glioma cells.

Conclusions

We inferred that Rab21 silencing can induce apoptosis and inhibit proliferation in human glioma cells, indicating that Rab21 might act as an oncogene and serve as a novel target for glioma therapy.

     

N-Benzoyl-12-nitrodehydroabietylamine-7-one, a novel dehydroabietylamine derivative, induces apoptosis and inhibits proliferation in HepG2 cells

The high biological activity of dehydroabietylamine derivatives has been reported previously. In this study, we aimed to screen 73 dehydroabietylamine derivatives as potential candidate inhibitors in liver cancer cells. Initially, the compounds structural activity relationship analysis was explored and N-benzoyl-12-nitrodehydroabietylamine-7-one (compound 81) was shown to have significant growth inhibitory activity in the human liver carcinoma cell line, HepG2. Further research into the anti-proliferative effect on HepG2 cells mediated by compound 81 was undertaken. The results suggest that compound 81 effectively induced apoptosis in HepG2 cells characterized by nuclear staining of DAPI, TUNEL assay and the activation of caspase-3. A decreased level of anti-apoptotic protein Bcl-2 and increased apoptotic Bax were also observed. Furthermore, Ki-67 protein staining and the BrdU incorporation assay showed that compound 81 significantly inhibited the proliferation of HepG2 cells. Cell cycle components analysis found that expression of cyclin D1 and cyclin B1 was reduced in HepG2 cells with compound 81 treatment, whereas the content of p21(Waf1/Cip1) was increased. Taken together, our data indicate that compound 81 induces apoptosis and inhibits proliferation in HepG2 cells, and may be a promising candidate in the development of a novel class of antitumor agents.     

MicroRNA-1284 inhibits proliferation and induces apoptosis in SGC-7901 human gastric cancer cells

Objectives

To explore the functional effects of miR-1284 on gastric cancer cells.

Results

Overexpression of miR-1284 significantly reduced SGC-7901 cell proliferation, but improved apoptosis. However, miR-1284 suppression displayed the inversed impacts. Furthermore, the protein levels of p27, Bax, procaspase-3 and active caspase-3 were up-regulated by miR-1284 overexpression, but were down-regulated by miR-1284 suppression. The level of Bcl-2 was down-regulated by miR-1284 overexpression, while it was up-regulated by miR-1284 suppression. The level of p21 was unaffected.

Conclusion

These results suggest that miR-1284 overexpression might be a suppressor for gastric cancer via controlling of cell proliferation and apoptosis.

     

Hexadecylphosphocholine inhibits phosphatidylcholine biosynthesis and the proliferation of HepG2 cells.

Hexadecylphosphocholine (HePC) is a synthetic lipid representative of a new group of antiproliferative agents, alkylphosphocholines (APC), which are promising candidates in anticancer therapy. Thus we have studied the action of HePC on the human hepatoblastoma cell line HepG2, which is frequently used as a model for studies into hepatic lipid metabolism. Non-toxic, micromolar concentrations of HePC exerted an antiproliferative effect on this hepatoma cell line. The incorporation into phosphatidylcholine (PC) of the exogenous precursor [methyl-14C]choline was substantially reduced by HePC. This effect was not due to any alteration in choline uptake by the cells, the degradation rate of PC or the release of PC into the culture medium. As anaccumulation of soluble choline derivatives points to CTP:phosphocholine cytidylyltransferase (CT) as the target of HePC activity we examined its effects on the different enzymes involved in the biosynthesis of PC via CDP-choline. Treatment with HePC altered neither the activity of choline kinase (CK) nor that of diacylglycerol cholinephosphotransferase (CPT), but it did inhibit CT activity in HepG2 cells. In vitro HePC also inhibited the activity of cytosolic but not membrane-bound CT. Taken together our results suggest that HePC interferes specifically with the biosynthesis of PC in HepG2 cells by depressing CT translocation to the membrane, which may well impair their proliferation.     

香烟烟雾提取物抑制肺泡上皮细胞的增殖并诱导其凋亡

香烟烟雾提取物（cigarette smoke extract,CSE）中含有丰富的氧化剂和自由基,由它所引起的氧化应激可导致肺泡壁的损伤进而发展为肺气肿.近年来,围绕CSE损伤肺泡壁作用机制的研究较为活跃,但其结果却一直存在着分歧.本实验的目的是观察CSE对肺泡Ⅱ型上皮细胞的损伤作用并探讨与其相关的分子机制.MTT比色法的结果显示,CSE以时间和剂量依赖性的方式降低细胞的增殖活力,流式细胞术的分析结果表明细胞增殖周期被阻滞在G1/S期.Hoechst 33258染色以及透射电镜观察从形态上确认CSE诱导细胞凋亡的发生,DNA梯的出现和Annexin V-FITC/碘化丙啶双染色的结果从分子水平得到进一步的证实.同时,运用流式细胞术检测到CSE诱导的凋亡伴随着Fas受体的高表达和caspase-3的显著活化.另外,使用H2DCFDA染色,经激光共聚焦显微镜术测得细胞内氧自由基在细胞受到CSE刺激以后大量快速积累.结果表明CSE能够抑制肺泡Ⅱ型上皮细胞来源的A549细胞的生长和增殖,并诱导细胞凋亡,由Fas受体所介导的死亡受体途径参与此凋亡过程,而CSE所引起的氧化应激则可能是阻止肺泡上皮细胞生长增殖并诱导其凋亡的始动因素.     

Matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway

The present study has investigated the anti-tumor activity and the underlying mechanisms of matrine on human colon cancer LoVo cells. Matrine inhibited the proliferation of the cells in dose- and time-dependent manners. The concentration required for 50 % inhibition (IC₅₀) was 1.15, 0.738, and 0.414 mg/ml, when cell were incubated with matrine for 24, 48, and 72 h, respectively. Matrine induced cell cycle arrest at G1 phase by downregulating cyclin D1 and upregulating p27 and p21. Matrine induced cell apoptosis by reducing the ratio of Bcl-2/Bax and increasing the activation of caspase-9 in a dose-dependent manner. Matrine displayed its anti-tumor activity by inactivating Akt, the upstream factor of the above proteins. Matrine significantly reduced the protein levels of pAkt, and increased the protein levels of other downstream factors, pBad and pGSK-3β. Specific inhibition of pAkt induced cell apoptosis, and synergized with matrine to inhibit the proliferation of LoVo cells; whereas activation of Akt neutralized the inhibitory effect of matrine on cell proliferation. The present study has demonstrated that matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway, indicating matrine may be a potential anti-cancer agent for colon cancer.     

VCC-1 over-expression inhibits cisplatin-induced apoptosis in HepG2 cells

Vascular endothelial growth factor-correlated chemokine 1 (VCC-1), a recently described chemokine, is hypothesized to be associated with carcinogenesis. However, the molecular mechanisms by which aberrant VCC-1 expression determines poor outcomes of cancers are unknown. In this study, we found that VCC-1 was highly expressed in hepatocellular carcinoma (HCC) tissue. It was also associated with proliferation of HepG2 cells, and inhibition of cisplatin-induced apoptosis of HepG2 cells. Conversely, down-regulation of VCC-1 in HepG2 cells increased cisplatin-induced apoptosis of HepG2 cells. In summary, these results suggest that VCC-1 is involved in cisplatin-induced apoptosis of HepG2 cells, and also provides some evidence for VCC-1 as a potential cellular target for chemotherapy.     

Ellipticine induces apoptosis through p53-dependent pathway in human hepatocellular carcinoma HepG2 cells

Ellipticine (5,11-dimethyl-6H-pyrido[4,3-b]carbazole), one of the simplest naturally occurring alkaloids, was isolated from the leaves of the evergreen tree Ochrosia elliptica Labill (Apocynaceae). Here, we reported that ellipticine inhibited the cell growth of human hepatocellular carcinoma cell line HepG2 and provided molecular understanding of this effect. The XTT assay results showed that ellipticine decreased the cell viability of HepG2 cells in a dose- and time-dependent manner, and the IC50 value was 4.1 microM. Furthermore, apoptosis induction by ellipticine in HepG2 cells was verified by the appearance of DNA fragmentation and annexin V-FITC/propidium iodide (PI) staining assay. Ellipticine treatment was found to result in the upregulation of p53, Fas/APO-1 receptor and Fas ligand. Besides, ellipticine also initiated mitochondrial apoptotic pathway through regulation of Bcl-2 family proteins expression, alteration of mitochondrial membrane potential (DeltaPsim), and activation of caspase-9 and caspase-3. Taken together, ellipticine decreased the cell growth and induced apoptosis in HepG2 cell.     

Stigmasterol isolated from marine microalgae Navicula incerta induces apoptosis in human hepatoma HepG2 cells

Plant sterols have shown potent anti-proliferative effects and apoptosis induction against breast and prostate cancers. However, the effect of sterols against hepatic cancer has not been investigated. In the present study, we assessed whether the stigmasterol isolated from Navicula incerta possesses apoptosis inductive effect in hepatocarcimona (HepG2) cells. According to the results, Stigmasterol has up-regulated the expression of pro-apoptotic gene expressions (Bax, p53) while down-regulating the anti-apoptotic genes (Bcl-2). Probably via mitochondrial apoptosis signaling pathway. With the induction of apoptosis caspase-8, 9 were activated. The DNA damage and increase in apoptotic cell numbers were observed through Hoechst staining, annexin V staining and cell cycle analysis. According to these results, we can suggest that the stigmasterol shows potent apoptosis inductive effects and has the potential to be tested as an anti-cancer therapeutic against liver cancer. [BMB Reports 2014; 47(8): 433-438]     

7,8-Dihydroxyflavone suppresses proliferation and induces apoptosis of human osteosarcoma cells

Recent studies suggest that 7,8-dihydroxyflavone (7,8-DHF) inhibits the development of several tumors.However,its role in osteosarcoma (OS) remains unknown.This...     

Cryptotanshinone induces ER stress-mediated apoptosis in HepG2 and MCF7 cells

The endoplasmic reticulum (ER) is a central organelle in eukaryotic cells that functions in protein synthesis and maturation, and also functions as a calcium storage organelle. Perturbation of ER functions leads to ER stress, which has been previously associated with a broad variety of diseases. ER stress is generally regarded as compensatory, but prolonged ER stress can activate apoptotic pathways in damaged cells. For this reason, pharmacological interventions that effectively enhance tumor death through ER stress have been the subject of a great deal of attention for anti-cancer therapy. Cryptotanshinone, the major active constituent isolated from the root of Salvia miltiorrhiza Bunge, has been recently evaluated for its anti-cancer activity, but the molecular mechanisms underlying these activities remain poorly understood. In particular, it remains completely unknown as to whether or not cryptotanshinone can induce ER stress. Herein, we identify cryptotanshinone as a potent stimulator of ER stress, leading to apoptosis in many cancer cell lines, including HepG2 hepatoma and MCF7 breast carcinoma, and also demonstrate that mitogen-activated protein kinases function as mediators in this process. Reactive oxygen species generated by cryptotanshinone have been shown to play a critical role in ER stress-induced apoptosis. Cryptotanshinone also evidenced sensitizing effects to a broad range of anti-cancer agents including Fas/Apo-1, TNF-α, cisplatin, etoposide or 5-FU through inducing ER stress, highlighting the therapeutic potential in the treatment of human hepatoma and breast cancer.     

Knockdown of TSP50 inhibits cell proliferation and induces apoptosis in P19 cells

Earlier studies identified testes-specific protease 50 (TSP50), which encodes a threonine protease, and showed that it was abnormally reactivated in many breast cancer biopsies. Further, it was shown to be negatively regulated by the p53 gene. However, little is known about the biological function of TSP50. In this study, we applied RNA interference to knockdown TSP50 gene expression in P19 murine embryonal carcinoma stem cells and tested whether this modulated the cell phenotype. The results showed that downregulation of TSP50 expression not only reduced cell proliferation, colony formation, and migration but also induced cell apoptosis. Further investigation revealed that knockdown of TSP50 resulted in greater sensitivity to doxorubicin-induced apoptosis and that activation of caspase-3 was involved in this process.