Targeted therapy with a selective BCL-2 inhibitor in older patients with acute myeloid leukemia

ABSTRACT Background: Older patients with acute myeloid leukemia are particularly difficult to treat, as they have a high risk of comorbidities, poor performance status and less tolerability to chemotherapy, as well as a more aggressive disease biology, responsible for the resistance to treatment. There is a need to explore novel therapeutic agents that are more effective and tolerable. Venetoclax, a BCL-2 inhibitor is a promising agent, as BCL-2 overexpression is present in 84% of acute myeloid leukemia patients at diagnosis and 95% of patients at relapse and has been associated with leukemia cell survival, chemotherapy resistance and poor prognosis. Objective: To review the available data about venetoclax in acute myeloid leukemia and how it can influence the treatment in older patients. Methods: Using the Pubmed database, we selected 29 articles published within the last 15 years, considering preclinical and clinical trials and review studies that combined venetoclax with acute myeloid leukemia. Results: Venetoclax has demonstrated promising results in preclinical and clinical trials, especially in patients with poor prognosis and the IDH mutation, with an excellent side-effect profile. However, resistance seems to develop rapidly with venetoclax monotherapy, because of antiapoptotic escape mechanisms. Conclusions: While the results with the use of venetoclax seem encouraging, it is not likely that targeting a single pathway will result in long-term disease control. The solution includes the use of combined therapy to block resistance mechanisms and enhance apoptosis, by reducing MCL-1, increasing BIM or inhibiting the complex IV in the mitochondria.

Apoptose e maturação placentária bovina: um estudo imunohistoquímico e morfométrico / Apoptosis and maturation of the bovine placenta: an immunohistochemical and morphometric study

A liberação da placenta após o parto envolve a perda da adesão materno-fetal e ocorre somente após a maturação completa do placentoma, que está relacionada com a diminuição da celularidade dos tecidos fetal e materno. A apoptose é requerida tanto para a maturação quanto para a liberação normal da placenta após o parto. O objetivo do presente estudo foi avaliar a ocorrência de apoptose em amostras de placenta de vacas em diferentes fases de gestação. Amostras de placentomas de 15 vacas saudáveis com 4 (n=5), 6 (n=5) e 9 (n=5) meses de gestação foram colhidas e processadas rotineiramente para a histologia, imunoistoquímica e histoquímica. As lâminas obtidas foram coradas em HE, Picrosirius Red e submetidas à análise imunoistoquímica das proteínas Caspase 3, Caspase 8, Bax e Bid. O aumento no número de vasos não necessariamente se associou ao aumento do calibre destes durante a evolução da gestação. Os resultados de histomorfometria revelaram aumento da marcação para Bax e Caspases 3 e 8 em células trofoblásticas binucleadas no final da gestação, enquanto o Bid se manteve sem alteração significativa. A histomorfometria das células trofoblásticas mononucleadas revelou expressão alta para Bax no início de gestação, com diminuição aos 6 meses de gestação e aumento das imunomarcações para Caspases 3 e 8, e Bid com o avanço gestacional. Os colágenos tipo I e III não aumentaram do terço médio ao final da gestação, o que é importante para a diminuição da adesão materno-fetal. Esses resultados confirmam que as Caspases 3 e 8, e o Bax estão envolvidos nos mecanismos de ativação da apoptose pela via intrínseca mitocondrial e/ou extrínseca ao longo da gestação em células trofoblásticas binucleadas, e que nas células trofoblásticas mononucleadas o Bax deixa de ser importante, enquanto o Bid e as Caspases 3 e 8 se tornam os mais significativos.

Placental release after birth involves loss of maternal-fetal adhesion and occurs only after complete maturation of the placentoma related to the decrease in cellularity of fetal and maternal tissues. Apoptosis is required for both the normal maturation and release of the placenta after birth. The aim of this study was to evaluate the occurrence of apoptosis in samples of the placenta of cows in different stages of gestation. Samples of 15 healthy cow placentomas at 4 (n=5), 6 (n=5) and 9 (n=5) months of gestation were harvested and processed for routine histology, immunohistochemistry and histochemistry. The slides were stained with HE, PicroSirius Red and subjected to immunohistochemical analysis of proteins Caspase 3, Caspase 8, Bax and Bid. Increase in number of vessels was not associated with increase in vascular area during progression of gestation. The results of histomorphometry revealed increased labeling for Bax and Caspases 3 and 8 in trophoblastic binucleated cells in late pregnancy, where the Bid remained without significant change. Histomorphometry analyzing the mononuclear trophoblast cells showed a high expression for Bax in early pregnancy, but decreased at 6 months of gestation. Immunolabeling revealed increased Caspases 3/8 and Bid with advancing of gestation. Further evaluation of type I and III collagen showed a decrease of both types of collagens at the end of gestation, what is very important for the reduction of maternal-fetal adhesion. These results confirm that Caspases 3 and 8 and Bax are involved in the mechanisms of activation of apoptosis through mitochondrial intrinsic and/or extrinsic pathway during pregnancy in trophoblastic binucleated cells. In mononuclear trophoblast cells Bax looses importance in the apoptosis process, awhile Bid and caspases 3 and 8 become the most significant.

Experimental research on the mechanisms of human multiple myeloma LP-1 cell apoptosis induced by oridonin / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the effects of oridonin (Ori) on human multiple myeloma (MM) cell line LP-1 apoptosis and its mechanisms.</p><p><b>METHODS</b>The human MM LP-1 cells were incubated in vitro by different concentrations of Ori. The proliferation activities of LP-1 cells were detected using MTT assay. The apoptosis rate of LP-1 cells was detected using Annexin V/PI double staining method. The ultrastructural changes of LP-1 cells were observed under transmission electron microscope (TEM) after they were treated with Ori. The mRNA expression of apoptosis correlated genes were detected using Real-time PCR.</p><p><b>RESULTS</b>Ori inhibited the proliferation of LP-1 cells in a dose- and time-dependent way. Results of Annexin V/PI double staining method showed that, along with increased drug concentration and prolonged drug action time, the apoptosis rate of LP-1 cells significantly increased. Under TEM, chromatin margination and mitochondrial swelling could be seen in LP-1 cells after they were treated by Ori. The mRNA expressions of PDCD5 and Bid were up-regulated, and those of Bcl-2 and NK-kappaB were down-regulated after action of Ori.</p><p><b>CONCLUSIONS</b>Ori induced cell apoptosis by up-regulating the mRNA expression of Bid and down-regulating the mRNA expression of Bcl-2 to decrease the mitochondrial membrane potential, trigger mitochondrial apoptosis way of LP-1 cells. Ori, also as the inhibitor of NF-kappaB activities, blocked the NF-kappaB activation, induced cell apoptosis, and inhibited the cell proliferation. Of them, it is necessary to further study the role of PDCD5 as an apoptosis promoter.</p>

Mycophenolic acid mediated mitochondrial membrane potential transition change lead to T lymphocyte apoptosis / 대한외과학회지

PURPOSE: This study demonstrated that apoptosis induced by mycophenolic acid (MPA) is mediated by mitochondrial membrane potential transition (MPT) changes in Jurkat cells. METHODS: Cell viability and MPT changes were measured by flow cytometry. Western blotting was performed to evaluate the expression of Bcl-2 family proteins, Bid, truncated Bid (tBid), cytochrome c, voltage dependent anion channel (VDAC), poly ADP-ribose polymerase (PARP), and protein kinase C-delta (PKC-delta). The catalytic activity of caspase-9 and -3 was also measured. RESULTS: Cell viability was decreased in time- and dose-dependent manners. Bcl-2 protein expression was decreased, but Bax protein expression was identified. A decreased Bcl-XL /Bcl-XS ratio was also noted. The expression of tBid protein also increased in a time-dependent manner in Jurkat cells treated with MPA. While normal MPT appeared as orange fluorescence, abnormal MPT corresponded to green fluorescence. Green fluorescence increased as orange decreased in the MPA-treated cells. Significantly increased concentrations of MPA induced the release of cytosolic cytochrome c. MPA also augmented the catalytic activity of caspase-9 and caspase-3 in Jurkat cells. Our findings demonstrated that MPA-induced apoptosis is mediated by MPT changes accompanied by decreased Bcl-XL expression and the appearance of tBid protein. The release of cytosolic cytochrome c from mitochondria and increased catalytic activity of caspase-9 and caspase-3 were observed in MPA-treated Jurkat cells. CONCLUSION: These results suggest that mitochondrial dysfunction caused by MPA induces human T lymphocyte apoptosis.

Apoptotic mechanism of WJH-6, a novel polyamine conjugate, on K562 and HL-60 cells / 药学学报

In the present study, the apoptotic mechanism and polyamine transporter recognition of WJH-6, a novel polyamine conjugate, were investigated in K562 and HL-60 cells. The cytotoxicity of WJH-6 was assessed by MTT assay; cell cycle distribution and apoptosis were measured by flow cytometry; the protein expression of Caspase-3, Caspase-8, Caspase-9, Bid and mitochondrial membrane potential (MMP) were evaluated by high content screening (HCS) analysis; the protein expression of cytochrome c was measured by Western blotting. The results showed that WJH-6 could be recognized and transported by polyamine transporter (PAT). Furthermore, WJH-6 was able to inhibit K562 and HL-60 cells proliferation and induce apoptosis. This apoptotic effect was relative to MMP loss, cytochrome c release from mitochondria to cytoplasm and the activation of Caspase-8, Caspase-9, Caspase-3 and Bid. These results suggested that WJH-6-induced K562 and HL-60 cells apoptosis was related with mitochondrial damage.

Association between myocardial calpain activation and apoptosis in lipopolysaccharide-induced septic mouse model / 中华心血管病杂志

<p><b>OBJECTIVE</b>in septic mice, myocardial calpain was activated and induced caspase-3 activation, the association between calpain activation and apoptosis was explored in this experiment.</p><p><b>METHODS</b>in in vivo model, adult C57 mice were injected with lipopolysaccharide (LPS, 4 mg/kg, i.p.) to induce sepsis. Myocardial calpain and caspase-3 activities, protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were detected by Western blot analysis and myocardial apoptosis was detected by TUNEL, myocardiac function was evaluated by Langendorff system. In in vitro model, adult rat cardiomyocytes were incubated with LPS (1 microg/ml) or co-incubated with calpain inhibitor-III (10 micromol/L), calpain activity, caspase-3 activity, protein levels of Bcl-2 and Bid, and cardiomyocyte apoptosis were detected.</p><p><b>RESULTS</b>in septic mice, myocardial calpain and caspase-3 activity were increased up to 2.7- and 1.8-folds, respectively. Both calpain inhibitor-III and PD150606 significantly attenuated the increase of caspase-3 activity. Myocardial protein levels of calpain-1, calpain-2, calpastatin, Bcl-2 and Bid were similar between control and septic mice, and no cleavage of both Bcl-2 and Bid was found in septic mice. Calpain inhibitor-III significantly improved myocardial function in septic mice. In in vitro model, calpain and caspase-3 activities were increased after 4 h LPS treatment, co-treatment with calpain inhibitor-III prevented caspase-3 activity increase, protein Bcl-2 and Bid were similar between normal cardiomyocytes and LPS-treated cardiomyocytes. Cardiomyocyte apoptosis was similar in in vivo and in vitro septic models.</p><p><b>CONCLUSION</b>myocardial calpain activity is increased in LPS induced septic mice, subsequent caspase-3 activation may contribute to myocardial dysfunction in septic mice without aggravating myocardial apoptosis and Bcl-2 and Bid are not involved on calpain induced caspase-3 activation in our model.</p>

The cytosolic domain of Bcl-2 forms small pores in model mitochondrial outer membrane after acidic pH-induced membrane association / 生物医学工程学杂志

The permeability of mitochondrial outer membrane (MOM) is regulated by the proteins of the Bcl-2 family via their interactions at the membrane. While pro-apoptotic Bax protein promotes MOM permeabilization (MOMP) releasing cytochrome c after activation by BH3-only protein, anti-apoptotic Bcl-2 protein protects MOM. However both Bax and Bcl-2 can form pores in model membranes. Unlike Bax pore that has been extensively studied and reported to be directly linked to MOMP, Bcl-2 pore is much less known; thus we investigated the pore-forming property of recombinant Bcl-2 lacking the C-terminal transmembrane sequence (Bcl-2deltaTM) in liposomal membranes of MOM lipids. We found that: (1) Bcl-2 formed pores at acidic pH that induced the association of Bcl-2 with liposome; (2) Bcl-2 pore size was dependent on Bcl-2 concentration, suggesting that oligomerization is involved in Bcl-2 pore formation; (3) Unlike Bax pore that could release large molecules up to 2 mega-Da, Bcl-2 pore was smaller and could only release the molecules of a few kilo-Da. Therefore, Bcl-2 and Bax may form different size pores in MOM, and while the large pore formed by Bax may release cytochrome c during apoptosis, the small pore formed by Bcl-2 may maintain the normal MOM permeability.

The Bax BH3 peptide H2-H3 promotes apoptosis by inhibiting Bcl-2's pore-forming and anti-Bax activities in the membrane / 生物医学工程学杂志

Pore-formation and protein-protein interactions are considered to play critical roles in the regulation of apoptosis by Bcl-2 family proteins. During the initiation of apoptosis, the anti-apoptotic Bcl-2 and the pro-apoptotic Bax form different pores to regulate the permeability of mitochondrial outer membrane, playing their opposite functions. Overexpression of Bcl-2 has been found in various cancer cells, therefore it is gaining widespread interest to discover small molecules to compromise Bcl-2 function for anti-cancer treatment. Since Bax binds to Bcl-2's hydrophobic groove via its BH3 domain (composed of helices 2 and 3), by which their functions are inhibited each other, the H2-H3 peptide that contains the functional BH3 domain of Bax has been considered as a potential Bcl-2 antagonist. We recently reported that Bax peptide H2-H3 promotes cell death by inducing Bax-mediated cytochrome c release and by antagonizing Bcl-2's inhibitory effect on Bax. However, the mechanism of how H2-H3 inhibits the anti-apoptotic activity of Bcl-2 remains poorly understood. To address this question, we reconstituted the Bcl-2 or Bax pore-forming process in vitro. We found that H2-H3 inhibited Bcl-2's pore formation and neutralized Bcl-2's inhibitory effect on Bax pore formation in the membrane, whereas the mutant H2-H3 peptide that does not induce apoptosis in cells was shown to have no effect on Bcl-2's activities. Thus, inhibiting Bcl-2's pore-forming and anti-Bax activities in the membrane is strongly correlated with H2-H3's pro-apoptosis function in cells.

Therapeutic Modulation of Apoptosis: Targeting the BCL-2 Family at the Interface of the Mitochondrial Membrane

A vast portion of human disease results when the process of apoptosis is defective. Disorders resulting from inappropriate cell death range from autoimmune and neurodegenerative conditions to heart disease. Conversely, prevention of apoptosis is the hallmark of cancer and confounds the efficacy of cancer therapeutics. In the search for optimal targets that would enable the control of apoptosis, members of the BCL-2 family of anti- and pro-apoptotic factors have figured prominently. Development of BCL-2 antisense approaches, small molecules, and BH3 peptidomimetics has met with both success and failure. Success-because BCL-2 proteins play essential roles in apoptosis. Failure-because single targets for drug development have limited scope. By examining the activity of the BCL-2 proteins in relation to the mitochondrial landscape and drawing attention to the significant mitochondrial membrane alterations that ensue during apoptosis, we demonstrate the need for a broader based multi-disciplinary approach for the design of novel apoptosis-modulating compounds in the treatment of human disease.

Overcoming acquired resistance to tumor necrosis factor-related apoptosis-inducing ligand by Bcl-XL small interfering RNA in human colon cancer / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the reversing effect of Bcl-XL small interfering RNA (siRNA) on the acquired resistance to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in human colon cancer.</p><p><b>METHODS</b>Human colon cancer cells DLD1-TRAIL/R, with acquired resistance to TRAIL, were firstly transfected with Bcl-XL siRNA for 24 h followed by the treatment of TRAIL protein. The survival rate of DLD1-TRAIL/R cells was assessed by FACS analysis and cell number counting, respectively, and activation of its apoptotic signaling was evaluated by Western blot.</p><p><b>RESULTS</b>Bcl-XL siRNA effectively downregulated the expression of Bcl-XL protein and reversed the acquired resistance to TRAIL in DLD1-TRAIL/R cells. After combination treatment of Bcl-XL siRNA and TRAIL protein, the apoptotic rate of DLD1-TRAIL/R cells was more than 50% and survival rate was less than 40%, whereas there was no effect on the survival of DLD1-TRAIL/R cells after treatment with control treatment or TRAIL protein treatment alone (P < 0.05). Western blot analysis demonstrated that caspase-8, caspase-9, Bid, caspase-3, and poly (ADP-ribose) polymerase (PARP) were obviously activated after combination treatment with Bcl-XL siRNA and TRAIL protein, and the release of cytochrome C was also significantly increased.</p><p><b>CONCLUSION</b>Bcl-XL siRNA can effectively reverse the acquired resistance to TRAIL in human colon cancer cells, suggesting that it might be a new strategy for overcoming the resistance in cancer therapy.</p>

Analysis of the NF-kappaB and Apoptosis Inducing Genes in Bladder Tumor / 대한비뇨기과학회지

PURPOSE: A multi-subunit transcription factor NF-kappaB mediates the antiapoptotic signals in several cancer cell lines and it is activated in a broad range of human tumors. In this study, we investigated whether the expression levels of the NF-kappaB and the apoptosis inducing genes were related to the pathogenesis and clinical properties of human bladder tumor. MATERIALS AND METHODS: The expressions of NF-kappaB, BCL2-associated X protein (BAX), BCL2-associated death protein (BAD) and BH3-interacting domain death agonist protein (BID) were investigated by performing immunohistochemical staining on 133 archival bladder tissue paraffin blocks; these blocks included 122 transitional cell carcinomas of the urinary bladder and 11 normal bladder mucosae. RESULTS: The expression levels of NF-kappaB were significantly higher in the bladder tumors than those of the normal bladder mucosae (p=0.001). The expression levels of BAX in the superficial and low-grade (grade 1 and 2) bladder tumors were significantly enhanced more than those of the high-grade and invasive cases (p=0.042 and p=0.045, respectively), while the expression levels of BAD in the tumor tissues and low-grade tumors were significantly elevated compared with those of the normal mucosae and high grade tumor (p=0.007 and p=0.048, respectively). But the expressions of BID were not correlated with any pathologic and clinical properties. CONCLUSIONS: The expressions of the NF-kappaB and apoptosis inducing genes such as BAX and BAD are strongly associated with the pathogenesis and clinical properties of bladder tumor. (Korean J Urol 2007;48:483-488)

Role of Bid protein in the mitochondria and Endoplasmic Reticulum associated apoptotic pathway / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the role of Bid protein in the mitochondria and endoplasmic reticulum (ER) associated apoptotic pathway.</p><p><b>METHODS</b>Apoptosis of MUTZ-1 cells induced by homoharringtonine (HHT) was measured by FACS. Mitochondria and ER associated apoptotic pathway was detected by RT-PCR and Western blotting. And the translocation of Bid protein was measured by laser scanning confocal microscope (LSCM).</p><p><b>RESULTS</b>After exposure of MUTZ-1 to HHT at 0.05 microg/ml for 24 h, typical ER-stress phenomenon induced apoptotic cells and release of Ca2+ from the cytosolic Ca2+ storage and the loss of mitochondrial membrane potential were observed. RT-PCR analysis revealed that mRNAs for ER stress-associated proapoptotic factor were markedly increased at 4 h after 0.05 microg/ml HHT treatment and peaked at 12 h, then decreased steady. Activation of caspase protein was also observed at 8 h. The translocation of Bid protein from ER to mitochondria was observed at 12 h after HHT treatment.</p><p><b>CONCLUSION</b>HHT can induce MUTZ-1 cells apoptosis. The cell death may be likely mediated by the ER stress pathway as well as mitochondrial pathway and Bid protein may be the cross talk of the two apoptotic pathways.</p>

Mitochondrial transmembrane potential loss caused by reactive oxygen species plays a major role in sodium selenite-induced apoptosis in NB4 cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the role of reactive oxygen species (ROS) and ROS-caused mitochondrial transmembrane potential loss in sodium selenite-induced apoptosis in NB4 cells.</p><p><b>METHODS</b>ROS production was measured by ROS-specific probe DCFH-DA. Sodium selenite mitochondrial transmembrane potential loss was evaluated by flow cytometry with Rh123 staining. Protein levels of cytochrome C, Bid, Bcl-xl, and Bax were measured by Western blot using protein-specific antibodies. NB4 cells were pre-incubated by MnTmPy or BSO before selenite treatment to further confirm the effects of ROS on NB4 cells.</p><p><b>RESULTS</b>20 micromol/L sodium selenite induced ROS production and mitochondrial transmembrane potential loss in NB4 cells time-dependently. Cytochrome C accumulated in cytoplasm after selenite treatment. Sodium selenite also downregulated Bcl-xl and activated Bax and Bid at protein level. Pretreatment with antioxidant MnTmPy almost fully abrogated the proapoptotic effect of sodium selenite prevented the cleavage of Bid protein and in turn the mitochondrail transmembrane potential loss. On the contrary, pretreatment with BSO intensified the mitochondrail transmembrane potential loss induced by sodium selenite.</p><p><b>CONCLUSIONS</b>Sodium selenite may induce apoptosis by inducing ROS production in NB4 cells, which leads to the downregulation of Bcl-xl, upregulation of Bax, and cleavage and activation of Bid. Bax and tBid then agregate on mitochondrial membrane, which in turn causes a decrease of mitochondrial transmembrane potential and release of cytochrome C into cytoplasm.</p>

Role of Bcl-xL in the cathepsin D-associated apoptosis of K562 cells / 中国实验血液学杂志

The purpose of study was to explore the possible functions of Bcl-xL in the glucosamine sulfate-induced apoptosis of chronic myeloid leukemia K562 cells. Light microscopy and Wright-Giemsa staining were used to investigate the morphologic evidences for apoptosis of K562 cells induced by glucosamine sulfate (GS); immunofluorescence was used to observe the translocation of cathepsin D and cytochrome C during the apoptosis; Western blot was performed to detect the expression of Bcl-xL, Bid, Bax in K562 cells treated by GS. The results showed that many vacuoles were observed in the cytoplasma of the K562 cells treated by GS; fluorescent signals of cathepsin D and cytochrome were fransformed from granules to disperse form by using immunofluorescence; the expression of Bcl-xL was found down-regulated in K562 cells treated by GS, but not in the cells pre-treated with pepstatin A; the significant changes were not detected in expression of Bax and Bid protein before or after apoptosis. It is concluded that Bcl-xL protein may mediate relationship between cathepsin D and mitochondia pathway, Cathepsin D may play an important role in the GS inducing apoptosis of K562 cells through downregulation of Bcl-xL expression.

Cap-independent protein translation is initially responsible for 4-(N-methylnitrosamino)-1-(3-pyridyl)-butanone (NNK)-induced apoptosis in normal human bronchial pithelial cells

Evidences show that eukaryotic mRNAs can perform protein translation through internal ribosome entry sites (IRES). 5'-Untranslated region of the mRNA encoding apoptotic protease-activating factor 1 (Apaf-1) contains IRES, and, thus, can be translated in a cap-independent manner. Effects of changes in protein translation pattern through rapamycin pretreatment on 4-(methylnitrosamino)-1-(3-pyridyl)-butanone(NNK, tobacco-specific lung carcinogen)-induced apoptosis in human bronchial epithelial cells were examined by caspase assay, FACS analysis, Western blotting, and transient transfection. Results showed that NNK induced apoptosis in concentration- and time-dependent manners. NNK-induced apoptosis occurred initially through cap-independent protein translation, which during later stage was replaced by cap-dependent protein translation. Our data may be pplicable as the mechanical basis of lung cancer treatment.

The Mechanism of Intracellular Signal Pathway that Baicalin Hydrate Elevate Chemotherapeutic Response of Cervical Carcinoma / 대한산부인과학회잡지

Baicalin is flavonoid and major component of PC-SPES. Flavonoids including baicalin have been reported to not only function as anti-oxidant but also cause cytotoxic effect. Baicalin hydrate has been reported to induce cell death, however the mechanism by which baicalin hydrate induces the apoptosis of cancer cells is still unclear. To evaluate the mechanistic insights of apoptosis by baicalin hydrate, we tested the activities of apoptosis signaling pathway in HeLa cells. The viability of HeLa and HeLa s3 cells was markedly decreased by baicalin hydrate in a dose- and time- dependent method. Baicalin hydrate induced the apoptotic death of HeLa cells, which was characterized by the chromatin condensation of the nuclei and phosphorylation of histone H2AX. Baicalin hydrate increased the sub-G1 DNA content of HeLa cell lines. Baicalin hydrate digested Bid protein, increased Bak protein level and also, induced mitochondrial dysfunction disrupted as shown as the mitochondrial membrane potential. It activated caspase-3, thereby resulted in cleavage of poly (ADP) ribose polymerase (PARP).