Evidence for two modes of development of acquired tumor necrosis factor-related apoptosis-inducing ligand resistance. Involvement of Bcl-xL

Previous studies have shown that repeated application of TRAIL induces acquired resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Using human prostate adenocarcinoma DU-145 and human pancreatic carcinoma MiaPaCa-2 cells as a model, we now demonstrate for the first time that two states of acquired TRAIL resistance can be developed after TRAIL treatment. Data from survival assay and Western blot analysis show that acquired TRAIL resistance was developed within 1 day and gradually decayed within 6 days after TRAIL treatment in both cell lines. After TRAIL treatment, the level of Bcl-xL increased and reached a maximum within 2 days and gradually decreased in both cell lines. Bcl-xL-mediated development of acquired TRAIL resistance was suppressed by knockdown of Bcl-xL expression. Protein interaction assay revealed that during the development of TRAIL resistance, Bcl-xL dissociated from Bad and then associated with Bax. Overexpression of mutant-type Bad (S136A), which prevents this dissociation, partially suppressed the development of acquired TRAIL resistance. Thus, our results suggest that (a) dissociation of Bad from Bcl-xL and (b) an increase in the intracellular level of Bcl-xL are responsible for development of acquired TRAIL resistance.     

Halocynthiaxanthin and peridinin sensitize colon cancer cell lines to tumor necrosis factor-related apoptosis-inducing ligand

Carotenoids are compounds contained in foods and possess anticarcinogenic activity. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer therapeutics due to its ability to induce apoptosis selectively in cancer cells. However, some tumors remain tolerant to TRAIL-induced apoptosis. Therefore, it is important to develop agents that overcome this resistance. We show, for the first time, that certain carotenoids sensitize cancer cells to TRAIL-induced apoptosis. Combined treatment with halocynthiaxanthin, a dietary carotenoid contained in oysters and sea squirts, and TRAIL drastically induced apoptosis in colon cancer DLD-1 cells, whereas each agent alone only slightly induced apoptosis. The combination induced nuclear condensation and poly(ADP-ribose) polymerase cleavage, which are major features of apoptosis. Various caspase inhibitors could attenuate the apoptosis induced by this combination. Furthermore, the dominant-negative form of a TRAIL receptor could block the apoptosis, suggesting that halocynthiaxanthin specifically facilitated the TRAIL signaling pathway. To examine the molecular mechanism of the synergistic effect of the combined treatment, we did an RNase protection assay. Halocynthiaxanthin markedly up-regulated a TRAIL receptor, death receptor 5 (DR5), among the death receptor-related genes, suggesting a possible mechanism for the combined effects. Moreover, we examined whether other carotenoids also possess the same effects. Peridinin, but not alloxanthin, diadinochrome, and pyrrhoxanthin, induced DR5 expression and sensitized DLD-1 cells to TRAIL-induced apoptosis. These results indicate that the combination of certain carotenoids and TRAIL is a new strategy to overcome TRAIL resistance in cancer cells.     

Involvement of tumor necrosis factor-related apoptosis-inducing ligand in NK cell-mediated and IFN-gamma-dependent suppression of subcutaneous tumor growth

Natural killer (NK) cells and interferon- (IFN) gamma have been implicated in immune surveillance against tumor development. Here we show tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), which is a type II membrane protein belonging to the TNF family and plays a critical role in the NK cell-mediated and IFN-gamma-dependent suppression of subcutaneous growth of TRAIL-sensitive tumors. Administration of a neutralizing monoclonal antibody against TRAIL promoted outgrowth of subcutaneously inoculated TRAIL-sensitive tumors (L929, LB27.4, and Renca) but not TRAIL-resistant tumors (P815 and B16). Such a protective effect of TRAIL against TRAIL-sensitive tumors was abrogated in NK cell-depleted or IFN-gamma-deficient mice. These results suggested a substantial role of TRAIL as the effector molecule that eliminates subcutaneously developing TRAIL-sensitive tumors.     

Wogonin enhances antitumor activity of tumor necrosis factor-related apoptosis-inducing ligand in vivo through ROS-mediated downregulation of cFLIPL and IAP proteins

Combination of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) with other agents is a promising strategy to overcome TRAIL resistance in malignant cells. Wogonin, a flavonoid originated from Scutellaria baicalensis Georgi, has been shown to enhance TRAIL-induced apoptosis in malignant cells in in vitro studies. However, whether wogonin enhances TRAIL’s antitumor activity in vivo has never been studied. In this study, the effect of combination of TRAIL and wogonin was tested in a non-small-cell lung cancer xenografted tumor model in nude mice. Consistent with the in vitro study showing that wogonin sensitized A549 cells to TRAIL-induced apoptosis, wogonin greatly enhanced TRAIL-induced suppression of tumor growth, accompanied with increased apoptosis in tumor tissues as determined by TUNEL assay. The expression levels of antiapoptotic proteins including long form of cellular FLICE-like inhibitory protein (cFLIP_L), X-linked inhibitor of apoptosis protein (XIAP), and cellular inhibitor of apoptosis protein 1 and 2 (cIAP-1 and cIAP-2) were markedly reduced in both cultured cells and xenografted tumor tissues after co-treatment with wogonin and TRAIL. The down-regulation of these antiapoptotic proteins was likely mediated by proteasomal degradation that involved intracellular reactive oxygen species (ROS), because wogonin robustly induced ROS accumulation and ROS scavengers butylated hydroxyanisole (BHA) and N-acetyl-l-cysteine (NAC) and the proteasome inhibitor MG132 restored the expression of these antiapoptotic proteins in cells co-treated with wogonin and TRAIL. These results show for the first time that wogonin enhances TRAIL’s antitumor activity in vivo, suggesting this strategy has an application potential for clinical anticancer therapy.     

Transforming growth factor-beta-mediated tumor necrosis factor-related apoptosis-inducing ligand expression and apoptosis in hepatoma cells requires functional cooperation between Smad proteins and activator protein-1

Transforming growth factor-beta (TGF-beta) has been shown to induce apoptotic cell death in normal and transformed hepatocytes. We recently identified tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as an important mediator of TGF-beta-induced apoptosis in hepatoma cells. In this study, we have further explored the mechanism by which TGF-beta up-regulates TRAIL expression. The 5'-flanking region of the TRAIL gene was isolated and characterized. Deletion mutants of the 5'-untranslated region of the TRAIL gene revealed a region comprising nucleotides -1950 to -1100 responsible for TRAIL induction following treatment with TGF-beta. Within this region, we have identified an activator protein-1 (AP-1) site indispensable for TGF-beta-mediated induction of TRAIL. Activation of this AP-1 site is mediated by a JunD.FosB heterodimer. Expression of DNSmad4, DNJunD, or DNFosB significantly impairs TGF-beta-mediated activation of the TRAIL promoter. Furthermore, with tRNA interference targeting Smad4, junD, FosB, we could abolish TRAIL expression and, subsequently, TGF-beta-induced TRAIL-mediated apoptosis in hepatoma cells. Our results reveal a new AP-1 site within the TRAIL promoter functionally involved in TGF-beta-induced TRAIL expression and apoptosis in hepatomas and thus provide evidence for the underlying mechanism by which TGF-beta might regulate cell death in liver cancer.     

Three adenovirus E3 proteins cooperate to evade apoptosis by tumor necrosis factor-related apoptosis-inducing ligand receptor-1 and -2

Adenovirus encodes multiple gene products that regulate proapoptotic cellular responses to viral infection mediated by both the innate and adaptive immune systems. The E3-10.4K and 14.5K gene products are known to modulate the death receptor Fas. In this study, we demonstrate that an additional viral E3 protein, 6.7K, functions in the specific modulation of the two death receptors for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). The 6.7K protein is expressed on the cell surface and forms a complex with the 10.4K and 14.5K proteins, and this complex is sufficient to induce down-modulation of TRAIL receptor-1 and -2 from the cell surface and reverse the sensitivity of infected cells to TRAIL-mediated apoptosis. Down-modulation of TRAIL-R2 by the E3 complex is dependent on the cytoplasmic tail of the receptor, but the death domain alone is not sufficient. These results identify a mechanism for viral modulation of TRAIL receptor-mediated apoptosis and suggest the E3 protein complex has evolved to regulate the signaling of selected cytokine receptors.     

Deficient tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) death receptor transport to the cell surface in human colon cancer cells selected for resistance to TRAIL-induced apoptosis

Many tumor cell types are sensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis. Incubation of TRAIL-sensitive cells with TRAIL invariably leads to resistant survivors even when high doses of TRAIL are used. Because the emergence of resistance to apoptosis is a major concern in successful treatment of cancer, and TRAIL survivors may contribute to therapeutic failure, we investigated potential resistance mechanisms. We selected TRAIL-resistant SW480 human colon adenocarcinoma cells by repeatedly treating them with high and/or low doses of TRAIL. The resulting TRAIL-resistant clones were not cross-resistant to Fas or paclitaxel. Expression of modulators of apoptosis was not changed in the resistant cells, including TRAIL receptors, cFLIP, Bax, Bid, or IAP proteins. Surprisingly, we found that DISC formation was deficient in multiple selected TRAIL-resistant clones. DR4 was not recruited to the DISC upon TRAIL treatment, and caspase-8 was not activated at the DISC. Although total cellular DR4 mRNA and protein were virtually identical in TRAIL-sensitive parental and TRAIL-resistant clones, DR4 protein expression on the cell surface was essentially undetectable in the TRAIL-resistant clones. Moreover, exogenous DR4 and KILLER/DR5 were not properly transported to the cell surface in the TRAIL-resistant cells. Interestingly, TRAIL-resistant cells were resensitized to TRAIL by tunicamycin pretreatment, which increased cell surface expression of DR4 and KILLER/DR5. Our data suggest that tumor cells may become resistant to TRAIL through regulation of the death receptor cell surface transport and that resistance to TRAIL may be overcome by the glycosylation inhibitor/endoplasmic reticulum stress-inducing agent tunicamycin.     

Requirement of c-Jun NH2-terminal kinase activation in interferon-alpha-induced apoptosis through upregulation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in Daudi B lymphoma cells

Interferon alpha (IFN-alpha) inhibits growth, at least in part, through induction of apoptosis. However, the molecular mechanisms underlying IFN-alpha-induced apoptosis are not completely understood. In the present study, we found that IFN-alpha induced a sustained activation of c-Jun N-terminal kinase 1 (JNK1), but not extracellular kinases (ERKs), in Daudi B lymphoma cells, as assessed by Western blotting using phospho-specific antibodies. Several lines of evidence support the notion that the IFN-alpha-induced activation of JNK is responsible for IFN-alpha-induced apoptosis, at least in part, through upregulation of TNF-related apoptosis-inducing ligand (TRAIL). First, pretreatment of Daudi cells with a JNK inhibitor reduced IFN-alpha-induced upregulation of TRAIL and loss of mitochondrial membrane potential (DeltaPsim) and annexin-positive cells, which was assessed by flow cytometry. Second, a dominant-negative form of JNK1 (dnJNK1) also reduced these apoptotic events, while a constitutively active form of JNK1, MKK7-JNK1beta, enhanced them. Finally, treatment with IFN-alpha enhanced the promoter activity of the TRAIL gene, which was partially abrogated by either JNK inhibitor or dnJNK1, while it was moderately enhanced by MKK7-JNK1beta. These findings are useful for understanding molecular mechanisms of IFN-alpha-induced apoptosis and also for development of treatment modalities of some tumors with IFN-alpha.     

Expression of osteoprotegerin, receptor activator of nuclear factor kappa-B ligand, tumor necrosis factor-related apoptosis-inducing ligand, stromal cell-derived factor-1 and their receptors in epithelial metastatic breast cancer cell lines

ABSTRACT: BACKGROUND: While breast cancer (BC) is the major cause of death among women worldwide, there is no guarantee of better patient survival because many of these patients develop primarily metastases, despite efforts to detect it in its early stages. Bone metastasis is a common complication that occurs in 65-80 % of patients with disseminated disease, but the molecular basis underlying dormancy, dissemination and establishment of metastasis is not understood. Our objective has been to evaluate simultaneously osteoprotegerin (OPG), receptor activator of nuclear factor kappa B ligand (RANKL), tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), stromal cell-derived factor-1 (SDF-1), and their receptors (R) in 2 human BC cell lines, MDA-MB-231 and MCF-7. METHODS: OPG, RANKL, TRAIL and SDF-1 expression and release, in addition to the expression of their receptors has been investigated using immunofluorescence, imunocytochemistry and ELISA analyses. RESULTS: MCF-7 cells released higher levels of OPG in conditioned media (CM) than MDA-MB-231 cells; 100 % of both types of cell expressed OPG, RANKL, TRAIL and SDF-1. Moreover, 100 % in both lines expressed membrane RANKL and RANK, whereas only 50 % expressed CXCR4. Furthermore, 100 % expressed TRAIL-R1 and R4, 30-50 % TRAIL-R2, and 40-55 % TRAIL-R3. CONCLUSIONS: MCF-7 and MDA-MB-231 cells not only released OPG, but expressed RANKL, TRAIL and SDF-1. The majority of the cells also expressed RANK, CXCR4 and TRAIL-R. Since these ligands and their receptors are implicated in the regulation of proliferation, survival, migration and future bone metastasis during breast tumor progression, assessment of these molecules in tumor biopsies of BC patients could be useful in identifying patients with more aggressive tumors that are also at risk of bone metastasis, which may thus improve the available options for therapeutic intervention.     

Simultaneous inhibition of epidermal growth factor receptor (EGFR) signaling and enhanced activation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor-mediated apoptosis induction by an scFv:sTRAIL fusion protein with specificity for human EGFR

Epidermal growth factor receptor (EGFR) signaling inhibition by monoclonal antibodies and EGFR-specific tyrosine kinase inhibitors has shown clinical efficacy in cancer by restoring susceptibility of tumor cells to therapeutic apoptosis induction. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-cancer agent with tumor-selective apoptotic activity. Here we present a novel approach that combines EGFR-signaling inhibition with target cell-restricted apoptosis induction using a TRAIL fusion protein with engineered specificity for EGFR. This fusion protein, scFv425:sTRAIL, comprises the EGFR-blocking antibody fragment scFv425 genetically fused to soluble TRAIL (sTRAIL). Treatment with scFv425:sTRAIL resulted in the specific accretion to the cell surface of EGFR-positive cells only. EGFR-specific binding rapidly induced a dephosphorylation of EGFR and down-stream mitogenic signaling, which was accompanied by cFLIP(L) down-regulation and Bad dephosphorylation. EGFR-specific binding converted soluble scFv425:sTRAIL into a membrane-bound form of TRAIL that cross-linked agonistic TRAIL receptors in a paracrine manner, resulting in potent apoptosis induction in a series of EGFR-positive tumor cell lines. Co-treatment of EGFR-positive tumor cells with the EGFR-tyrosine kinase inhibitor Iressa resulted in a potent synergistic pro-apoptotic effect, caused by the specific down-regulation of c-FLIP. Furthermore, in mixed culture experiments binding (L)of scFv425:sTRAIL to EGFR-positive target cells conveyed a potent apoptotic effect toward EGFR-negative bystander tumor cells. The favorable characteristics of scFv425:sTRAIL, alone and in combination with Iressa, as well as its potent anti-tumor bystander activity indicate its potential value for treatment of EGFR-expressing cancers.     

Phosphorylated galectin-3 mediates tumor necrosis factor-related apoptosis-inducing ligand signaling by regulating phosphatase and tensin homologue deleted on chromosome 10 in human breast carcinoma cells

Galectin-3 (GAL3), a beta-galactoside-binding lectin, confers chemoresistance to a wide variety of cancer cell types. It may exhibit anti- or pro-apoptotic activity depending on the nature of the stimulus. We report here that introducing phosphorylated galectin-3 (P-GAL3) into GAL3-null, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-resistant human breast carcinoma cells promotes TRAIL-induced apoptotic cell death by stimulating the phosphorylation/inactivation of the pro-apoptotic molecule Bad resulting in the inhibition of mitochondrial depolarization and the release of cytochrome c. Exposure of the transfectant cells to TRAIL leads to the recruitment of the initiator capase-8 followed by activation of the effector caspase-9, independent of cytochrome c, and subsequently the processing of the executioner caspase-3. P-GAL3 and phosphatase and tensin homologue deleted on chromosome 10 (PTEN) were coordinately expressed, with concomitant dephosphorylation of Akt in TRAIL-sensitive cells. In contrast, overexpression of phospho-mutant GAL3 (incapable of phosphorylation) failed to elicit similar responses. Depletion of PTEN using small interference RNAs reinstated Akt phosphorylation and conferred TRAIL resistance. In addition phosphatidylinositol 3-kinase inhibitors rendered the phospho-mutant GAL3-resistant cells sensitive to TRAIL. These findings suggest a pivotal role for P-GAL3 in promoting TRAIL sensitivity through activation of a nonclassic apoptotic pathway and identify P-GAL3 as a novel regulator of PTEN.     

Calyculin A causes sensitization to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis by ROS-mediated down-regulation of cellular FLICE-inhibiting protein (c-FLIP) and by enhancing death receptor 4 mRNA stabilization

Calyculin A (Cal A) is a serine/threonine phosphatase inhibitor that is capable of inducing apoptosis in cancer cells. In this study, we examined whether Cal A could modulate TRAIL-induced apoptosis in human renal carcinoma-derived Caki cells. Our results show that Cal A is capable of sensitizing Caki cells to TRAIL-induced apoptosis, as well as U2OS human osteosarcoma cells and A549 human lung adenocarcinoma epithelial cells. Cal A increases intracellular ROS production and down-regulates c-FLIP(L) expression. Interestingly, the down-regulation of protein phosphatase 1 (PP1) by PP1 siRNA also reduced c-FLIP(L) expression via reactive oxygen species production. Furthermore, Cal A induced death receptor 4 (DR4) mRNA and protein expression by enhancing DR4 mRNA stability. We also found that PP4 siRNA up-regulated DR4 mRNA and protein expression. Collectively, our results suggest that Cal A could enhance TRAIL-mediated apoptosis via the down-regulation of c-FLIP(L) and the up-regulation of DR4 in human renal cell carcinoma cell line Caki.     

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) decoy receptor TRAIL-R3 is up-regulated by p53 in breast tumor cells through a mechanism involving an intronic p53-binding site

Tumor necrosis factor-related apoptosis-inducing ligand receptor 3 (TRAIL-R3) is a decoy receptor for TRAIL, a member of the tumor necrosis factor family. In several cell types decoy receptors inhibit TRAIL-induced apoptosis by binding TRAIL and thus preventing its binding to proapoptotic TRAIL receptors. We studied the regulation of TRAIL-R3 gene expression in breast tumor cells treated with the genotoxic drug doxorubicin (DXR). The breast tumor cell line MCF-7 (p53 wild type) responded to DXR with a marked elevation of TRAIL-R3 expression at the mRNA, total protein, and cell surface levels. In contrast, in EVSA-T cells (p53 mutant) DXR did not induce increased expression of TRAIL-R3. In MCF-7 cells overexpressing the human papillomavirus protein E6, which causes p53 degradation, DXR-induced TRAIL-R3 expression was notably reduced. Furthermore, in MCF-7 cells overexpressing a temperature-sensitive p53 mutant (Val135), shifting the cultures to the permissive temperature was sufficient to induce the expression of TRAIL-R3. We also cloned and characterized a p53 consensus element located within the first intron of the human TRAIL-R3 gene. This element binds p53 and confers responsiveness to genotoxic damage to constructs of the TRAIL-R3 promoter in transient transfection experiments. Our results indicate that genotoxic treatments such as DXR, frequently used in cancer therapy, may also induce genes such as TRAIL-R3 that potentially have antiapoptotic actions and thus interfere with the TRAIL signaling system. This is particularly important in view of the proposed use of TRAIL in antitumor therapy.     

Human tumor necrosis factor alpha-induced protein eight-like 1 exhibited potent anti-tumor effect through modulation of proliferation,survival, migration and invasion of lung cancer cells

Molecular and Cellular Biochemistry - Lung cancer represents one of the most prevalent neoplasms across the globe. Tobacco smoking, exposure to different occupational and environmental carcinogens,...     

GDP-mannose-4,6-dehydratase (GMDS) deficiency renders colon cancer cells resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor- and CD95-mediated apoptosis by inhibiting complex II formation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through binding to TRAIL receptors, death receptor 4 (DR4), and DR5. TRAIL has potential therapeutic value against cancer because of its selective cytotoxic effects on several transformed cell types. Fucosylation of proteins and lipids on the cell surface is a very important posttranslational modification that is involved in many cellular events. Recently, we found that a deficiency in GDP-mannose-4,6-dehydratase (GMDS) rendered colon cancer cells resistant to TRAIL-induced apoptosis, resulting in tumor development and metastasis by escape from tumor immune surveillance. GMDS is an indispensable regulator of cellular fucosylation. In this study, we investigated the molecular mechanism of inhibition of TRAIL signaling by GMDS deficiency. DR4, but not DR5, was found to be fucosylated; however, GMDS deficiency inhibited both DR4- and DR5-mediated apoptosis despite the absence of fucosylation on DR5. In addition, GMDS deficiency also inhibited CD95-mediated apoptosis but not the intrinsic apoptosis pathway induced by anti-cancer drugs. Binding of TRAIL and CD95 ligand to their cognate receptors primarily leads to formation of a complex comprising the receptor, FADD, and caspase-8, referred to as the death-inducing signaling complex (DISC). GMDS deficiency did not affect formation of the primary DISC or recruitment to and activation of caspase-8 on the DISC. However, formation of secondary FADD-dependent complex II, comprising caspase-8 and cFLIP, was significantly inhibited by GMDS deficiency. These results indicate that GMDS regulates the formation of secondary complex II from the primary DISC independent of direct fucosylation of death receptors.     

Contribution of epigenetic silencing of tumor necrosis factor-related apoptosis inducing ligand receptor 1 (DR4) to TRAIL resistance and ovarian cancer

Dysregulation of apoptosis may support tumorigenesis by allowing cells to live beyond their normally intended life span. The various receptors for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are located on chromosome 8p21.2, a region frequently deleted in ovarian cancer. Lack of expression of TRAIL receptor 1 (death receptor 4, DR4) correlates with resistance to TRAIL-induced apoptosis in ovarian cancer cells. Reconstitution of DR4 in the TRAIL-resistant A2780 ovarian cancer cell line was investigated with the demethylating agent 5-aza-2'-deoxycytidine and transient gene transfer. Regulation of other genes in the TRAIL pathway by 5-aza-2'-deoxycytidine was assessed in DNA GeneChip experiments. Primary ovarian cancers were analyzed by methylation-specific PCR and immunohistochemical analysis of a tissue microarray. Regulation of DR4 expression by demethylation or transient transfection is of functional relevance for TRAIL resistance in an ovarian cancer cell line. Hypermethylation of the DR4 promoter could be found in 10 of 36 (27.7%) DNAs isolated from ovarian cancer tissue. In an independent set of 68 ovarian cancer cases, a complete loss or down-regulation of DR4 protein expression was observed 10.3% and 8.8% patients, respectively. A significant (P = 0.019) majority of these patients was below 50 years of age. Our findings show a functional relevance of the level of DR4 expression in ovarian cancer and suggest a substantial contribution of DR4 hypermethylation and consequent loss of DR4 expression to ovarian cancer pathogenesis, particularly in premenopausal patients.     

Celastrol inhibit the proliferation,invasion and migration of human cervical HeLa cancer cells through down-regulation of MMP-2 and MMP-9

The present study evaluated the anticancer potential of celastrol through down-regulation of matrix metalloproteinase-2 (MMP-2) and MMP-9. HeLa cells were incubated with different concentrations of celastrol (1, 10 and 100 µM) for 48h. Doxorubicin was used as a reference drug. Cancer cell migration, apoptosis, cell viability and mitochondrial fragmentation were evaluated following celastrol treatment. In addition, the expression level of MMP-2, MMP-9 and caspase-3 was evaluated following celastrol treatment. HeLa cell viability was 94.1 ± 7, 53.4 ± 4 and 36.3 ± 2% at 1-100 µM of celastrol, respectively. Apoptotic cell numbers were increased, and inhibition of larger wounds in cancer cells was observed following celastrol treatment. Celastrol-treated cells showed condensed nuclei and clumped mitochondria. Reduced expression of MMP-2 and MMP-9 and increased expression of caspase-3 were observed following celastrol treatment. Based on the experimental results, we are concluding that the celastrol was effective against HeLa cervical cancer cells.