Synthetic polysulfane derivatives induce cell cycle arrest and apoptotic cell death in human hematopoietic cancer cells

Natural polysulfanes including diallyltrisulfide (DATS) and diallyltetrasulfide (DATTS) from garlic possess antimicrobial, chemopreventive and anticancer properties. However these compounds exhibit chemical instability and reduced solubility, which prevents their potential clinical applicability. We synthesized six DATS and DATTS derivatives, based on the polysulfane motif, expected to exhibit improved physical and chemical properties and verified their biological activity on human leukemia cells.We identified four novel cytotoxic compounds (IC₅₀ values: compound 1, 24.96 ± 12.37 μM; compound 2, 22.82 ± 4.20 μM; compound 3, 3.86 ± 1.64 μM and compound 5, 40.62 ± 10.07 μM, compared to DATTS: IC₅₀: 9.33 ± 3.86 μM). These polysulfanes possess excellent differential toxicity, as they did not affect proliferating mononuclear blood cells from healthy donors.We further demonstrated ability of active compounds to induce apoptosis in leukemia cells by analysis of nuclear fragmentation and of cleavage of effector and executioner caspases. Apoptosis was preceded by accumulation of cells in G2/M phase with a pro-metaphase-like nuclear pattern as well as microtubular alterations. Prolonged and persistent arrest of cancer cells in early mitosis by the benzyl derivative identifies this compound as the most stable and effective one for further mechanistic and in vivo studies.     

Retinoic acid-induced asymmetric craniofacial growth and cleft palate in the to mouse fetus

The etiology and pathogenetic mechanisms of cleft palate (CP) are rather uncertain. Both genetic and environmental factors are known to cause failure of horizontalization and/or failure of fusion of the palatal shelves resulting in CP. Retinoic acid (RA)-induced CP in the mouse is reported to exhibit two peaks of incidence separated by a less sensitive window. The morphologic bases of the differential sensitivity are not known. The objectives of this study were to determine whether the TO mouse had similar peaks of sensitivity to RA-induced CP, and if it did, to evaluate the morphologic and histologic bases of CP induced at an early [Gestation Day (GD) 8]and at a late (GD 12) stage of embryonic development Single doses of all-trans-RA were administered to groups of mice on one of GD 8 to 15. On GD 18, fetuses were evaluated for the presence of CP, and the developmental stage of the palatal shelves was determined. All doses of RA were found to induce a high incidence of CP in the GD 8 to 13 treatment groups. GD 14 and 15 were not susceptible. There were no stage-dependent peaks or less sensitive windows, indicating that RA-induced CP in this strain is a continuum from GD 8 through 13. Morphologically clefting in the GD 8-RA treatment group was characterized by extreme hypoplasia (65% to 100%, depending on the dose) or agenesis (35% in the 200 mg/kg group) of the palatal shelves and associated with astomia, microstomia, aglossia, microglossia, and micrognathia with fusion of mandible, maxilla, and zygoma. Treatment on subsequent days of gestation resulted in CP with the shelves reaching progressively higher levels of maturity in terms of developmental staging. There was no case of CP with horizontalized shelves apposing but failing to fuse with each other. The facial skeleton of GD 12-RA group was hypoplastic but not malformed. Reduction in all dimensions of the cranium and mandible was highly significant (P < 0.001) in the GD 8-RA group, whereas there was a clear unbalance between the vertical growth and that in other directions in the CD 12-RA group. The CR length, head and body weights, and the protein content of heads of GD 8-RA-treated embryos were significantly reduced. Histologic studies showed that both the intrinsic and extrinsic muscles of the tongue and face, growth of the Meckel's cartilage, and ossification of the mandible were severely affected in the GD 8 treatment group, whereas these tissues were only moderately affected in the embryos of the GD 12-RA group. However, the quality of cytodifferentiation of the muscles was not affected in either group. These data provide evidence for the susceptibility continuum of CP in this strain. They also indicate that agenesis and hypoplasia of the palatal shelves and primordia of craniofacial skeleton and musculature contribute to CP, the relative involvement of the components depending on the stage of drug administration. In the absence of pronounced cell death, it appears that RA possibly produces its deleterious effects on the precursors of craniofacial primordia, such as the neural crest, by misexpression of developmentally important genes.     

Dose- and time-dependent effects of doxorubicin on cytotoxicity,cell cycle and apoptotic cell death in human colon cancer cells

The cytostatic drug doxorubicin is a well-known chemotherapeutic agent which is used in treatment of a wide variety of cancers. A key factor in the response of cancer cells to chemotherapeutic drugs is the activation of the apoptotic pathway, a pathway that is often impaired in chemoresistant colon cancer cells. The aim of the present study was to investigate the effects of doxorubicin in Hct-116 human colon carcinoma cells in order to clarify if a time/concentration range for optimal doxorubicin-induced apoptosis exists. We compared a treatment schedule were cells were bolus incubated for 3 h with doxorubicin followed by 24 h in drug-free medium, with a continuous doxorubicin treatment schedule for 24 h. Bolus incubation was carried out to determine effects of doxorubicin accumulated during the first 3 h, whereas continuous incubation allowed further (continuous) exposure to doxorubicin. We found that bolus (3 h) treatment with doxorubicin resulted in a dose-dependent decrease of viable cells and concomitant increase of apoptosis. Additionally, bolus (3 h) doxorubicin incubation led to phosphorylation of p53 at serine 392, induction of p21, G2 arrest and increase of proapoptotic protein Bax. In contrast, continuous (24 h) treatment with doxorubicin reduced the number of living cells with no parallel raise in the amount of dead cells. Continuous (24 h) treatment with 5 μM doxorubicin resulted in cell cycle arrest in G0/G1 phase that was neither accompanied by phosphorylation and activation of p53 nor enhanced expression of p21. These results suggest that doxorubicin is able to induce cell death by apoptosis only at particular dose and treatment conditions and imply a completely different cellular response following bolus or continuous exposure to doxorubicin.     

维甲酸诱导BALB/C近交系小鼠产生腭裂的剂量研究

目的:研究维甲酸诱导BALB/C近交系小鼠产生腭裂所需的剂量。方法:将40只BALB/C近交系小鼠分成四组,每组10只,在妊娠10 d时分别给予不同剂量的维甲酸,给药后观察所有孕鼠的反应,在妊娠15 d时解剖部分孕鼠,取胎鼠头部,行冠状切片,苏木精-伊红染色法(HE染色),进行观察。剩余孕鼠任其自然分娩,观察子鼠情况。结果:给予70 m g/kg维甲酸后,孕鼠组绝大多数表现腭裂动物模型所需特征。结论:70 m g/kg剂量维甲酸能够诱导BALB/C近交系小鼠产生可靠的腭裂动物模型。     

Effect of zeranol on expression of apoptotic and cell cycle proteins in murine placentae

Mycotoxins are chemicals produced by fungus and many of them are toxic to humans. Zeranol is a mycotoxin used to promote growth in cattle in North America; yet such a practice draws concern about the residual compound in meat in European countries. In the present study, the toxicity of zeranol was tested in a mouse model for reproduction. Pregnant ICR mice were given p.o. daily doses of zeranol at 0, 1, 10, 100 mg/kg for 4 days (from E13.5 to E16.5). Increased rates of fetal resorption at late gestation (E17.5) and preterm birth (<E18.5) were observed in mice treated with zeranol. The apparent factors causing these perinatal conditions were subsequently investigated. Perturbation of cell death or proliferation-related proteins might deter the growth and maintenance of the placentae, and the subsequent fetal resorption and preterm birth. Placental tissue isolated from pregnant mice at E17.5 showed that the expressions of Cdk2 and 4, Cyclin D1 and Bcl-xL were reduced in zeranol-treatment groups. The downregulations might signify growth or maintenance failure in the placentae. Furthermore, reduction in the signaling proteins Erk-1/2 in the placentae could trigger the decrease in the cell cycle/apoptosis proteins. In addition, relaxin is associated with preterm labor. An increase in placental Relaxin-1 expression could also contribute to early delivery in this study. Result of the current study suggested that exposure to zeranol might introduce adverse effect in pregnancy.     

Common differentially expressed proteins were found in mouse cleft palate models induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and retinoic acid

Cleft palate(CP) is a widely studied congenital malformation. However, its etiology and pathogenesis still remain unclear. Proteins are fundamental molecules that participate in every biological process within cells. In this study, we established CP mouse models induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and retinoic acid (RA), using proteomics technology isobaric tags for relative and absolute quantitation (iTRAQ) to investigate the key proteins in the formation of CP. Pregnant mice were given a gavage of TCDD 28μg/kg or retinoic acid 80mg/kg of body weight or equivalent corn oil at gestational day 10.5(GD10.5) and sacrificed at GD 17.5. Foetal mice were recorded and collected for further detection. Western blot was performed to verify the iTRAQ results. Eventually, we obtained 18 common differentially expressed proteins in TCDD group and RA group compared with normal control, 17 up-regulated and 1 down-regulated. 14-3-3sigma and Annexin A1 were up-regulated in experimental groups at GD17.5, which was consistent with Western blot. We speculated that the common differentially expressed proteins might be one of the molecular mechanisms in the formation of cleft palate.     

Effect of Tanshitone on prevention and treatment of retinoic acid-induced osteoporosis in mice

Objective To observe the prevention and therapeutic effects of tanshitone(TAN)on retinoic acid induced osteoporosis in mice.Methods The mice osteoporosis was induced by given retinoic acid intragasttrically for two weeks.The histomorphological features of bone were observed and biochemical indexes in serum(Ca,P,ALP,TRAP,E2,BGP)were determined after mice were given TAN at the dose of 40,80,160 mg·kg-1 respectively.Results Tanshitone can induce high conversion of osteoporosis.The levels of P,ALP,TRAP and BGP in the TAN groups were lower than the model group,while the E2 level was higher than the model group.Conclusions Tanshitone can prevent the loss bone in the experimental mice.The mechanism may be that it improves the level of estrogenic hormone and inhibits the high bone turnover.     

Differential modulation of PI3-kinase/Akt pathway during all-trans retinoic acid- and Am80-induced HL-60 cell differentiation revealed by DNA microarray analysis

All-trans retinoic acid (ATRA) and Am80 are natural and synthetic derivatives of Vitamin A and have been used in the fields of oncology and dermatology for years. Their action was considered to be achieved mainly through binding to nuclear hormone receptors, retinoic acid receptors (RARs), although they have been observed to have different biological effects. For example, the two compounds have similar effects on differentiation but different effects on proliferation in human promyelocytic leukemia cell line HL-60 cells. To elucidate the genes responsible for this and other differences, we attempted for the first time to determine the genes whose expressions were differentially modulated during the time course of HL-60 cell differentiation by ATRA and Am80 treatment up to 72h utilizing DNA microarray and clustering analyses. As a result, the expressions of 204 genes were found to be modulated differentially by ATRA and Am80. Among them, we focused on two components of the PI3-kinase/Akt signal transduction pathway, phosphoinositide-3-kinase, beta-catalytic subunit and ribosomal protein S6 kinase polypeptide 1, which are related to the regulation of cell proliferation and apoptosis. Their expressions were specifically suppressed by ATRA, which coincided with the suppressive effects of ATRA on the HL-60 cell proliferation. Moreover, PI3-kinase inhibitors suppressed the proliferation of Am80-treated cells to the same extent as ATRA did. These results indicated that these gene products play a role in HL-60 cell growth suppression during the late stage of differentiation. The complete data and a list of the genes are available at .     

Lower concentrations of receptor for advanced glycation end products and epiregulin in amniotic fluid correlate to chemically induced cleft palate in mice

This study investigated the correlation between differentially expressed proteins in amniotic fluid (AF) and cleft palate induced by all-trans retinoic acid (atRA), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. Seven proteins were differentially expressed at embryonic day (E) 16.5 in atRA and control groups as revealed by label-based mouse antibody array. Enzyme-linked immunosorbent assay was further used to detect the expression levels of these proteins in AF from E13.5 to E16.5 in atRA, TCDD, and control groups. The cleft palate groups showed lower concentrations of receptor for advanced glycation end products (RAGE) and epiregulin at E16.5. RAGE immunostaining obviously decreased in palatal tissue sections obtained from E14.5 to E16.5 in the cleft palate groups as revealed by immunohistochemistry. These findings indicate that reduced levels of RAGE and epiregulin in AF are correlated to chemically induced cleft palate in mice.     

17Alpha-estradiol arrests cell cycle progression at G2/M and induces apoptotic cell death in human acute leukemia Jurkat T cells

A pharmacological dose (2.5-10 μM) of 17α-estradiol (17α-E₂) exerted a cytotoxic effect on human leukemias Jurkat T and U937 cells, which was not suppressed by the estrogen receptor (ER) antagonist ICI 182,780. Along with cytotoxicity in Jurkat T cells, several apoptotic events including mitochondrial cytochrome c release, activation of caspase-9, -3, and -8, PARP degradation, and DNA fragmentation were induced. The cytotoxicity of 17α-E₂ was not blocked by the anti-Fas neutralizing antibody ZB-4. While undergoing apoptosis, there was a remarkable accumulation of G₂/M cells with the upregulatoin of cdc2 kinase activity, which was reflected in the Thr56 phosphorylation of Bcl-2. Dephosphorylation at Tyr15 and phosphorylation at Thr161 of cdc2, and significant increase in the cyclin B1 level were underlying factors for the cdc2 kinase activation. Whereas the 17α-E₂-induced apoptosis was completely abrogated by overexpression of Bcl-2 or by pretreatment with the pan-caspase inhibitor z-VAD-fmk, the accumulation of G₂/M cells significantly increased. The caspase-8 inhibitor z-IETD-fmk failed to influence 17α-E₂-mediated caspase-9 activation, but it markedly reduced caspase-3 activation and PARP degradation with the suppression of apoptosis, indicating the contribution of caspase-8; not as an upstream event of the mitochondrial cytochrome c release, but to caspase-3 activation. In the presence of hydroxyurea, which blocked the cell cycle progression at the G₁/S boundary, 17α-E₂ failed to induce the G₂/M arrest as well as apoptosis. These results demonstrate that the cytotoxicity of 17α-E₂ toward Jurkat T cells is attributable to apoptosis mainly induced in G₂/M-arrested cells, in an ER-independent manner, via a mitochondria-dependent caspase pathway regulated by Bcl-2.     

Supercritical carbon dioxide extract of Physalis peruviana induced cell cycle arrest and apoptosis in human lung cancer H661 cells

Physalis peruviana L. (PP) is a popular folk medicine used for treating cancer, leukemia, hepatitis, rheumatism and other diseases. In this study, our objectives were to examine the total flavonoid and phenol content of different PP extracts (aqueous: HWEPP; ethanolic: EEPP; supercritical carbon dioxide: SCEPP-0, SCEPP-4 and SCEPP-5) and their antiproliferative effects in human lung cancer H661 cells. Among all the extracts tested, results showed that SCEPP-5 possessed the highest total flavonoid (226.19 ± 4.15 mg/g) and phenol (100.82 ± 6.25 mg/g) contents. SCEPP-5 also demonstrated the most potent inhibitory effect on H661 cell proliferation. Using DNA ladder and flow cytometry analysis, SCEPP-5 effectively induced H661 cell apoptosis as demonstrated by the accumulation of Sub-G1 peak and fragmentation of DNA. SCEPP-5 not only induced cell cycle arrest at S phase, it also up-regulated the expression of pro-apoptotic protein (Bax) and down-regulated the inhibitor of apoptosis protein (IAP). Furthermore, the apoptotic induction in H661 cells was found to associate with an elevated p53 protein expression, cytochrome c release, caspase-3 activation and PARP cleavage. Taken together, these results conclude that SCEPP-5 induced cell cycle arrest at S phase, and its apoptotic induction could be mediated through the p53-dependent pathway and modification of Bax and XIAP proteins expression. The results have also provided important pharmacological backgrounds for the potential use of PP supercritical fluid extract as products for cancer prevention.     

全反式维甲酸联合猪胆酸钠对人卵巢癌细胞生长抑制作用的影响

目的 探讨维甲酸（ATRA）及猪胆酸钠（SBANa)联合反应对人卵巢癌细胞生长的抑制作用。方法 实验共分为三组：单用ATRA组、单用SBANa组及ATRA＋SBANa联合用药组。应用MTT比色法、流式细胞仪对COC1、COC2、CAOV3三种卵巢癌细胞系在不同浓度的ATRA及SBANa下进行检测。结果 ATRA及SBANa联合应用后，能增强抑制卵巢癌细胞生长作用，当达到ATRA10μmol/L SBANa 100μg/ml浓度时，G0、G1期细胞比例增加，G2M、S期细胞比例下降，细胞增殖速度较单独用药组减缓。MTT检测提示在联合用药浓度达到ATRA 10μmol/L SBANa 100μg/ml时，癌细胞抑制率最佳。结论 ATRA及SBANa联合应用可增强对卵巢癌细胞增殖的抑制作用，并在ATRA 30μmol/L SBANa 100μg/ml浓度时，促进癌细胞凋亡。     

Patulin causes DNA damage leading to cell cycle arrest and apoptosis through modulation of Bax, p and p proteins in skin of mice

Patulin (PAT), a mycotoxin found in apples, grapes, oranges, pear and peaches, is a potent genotoxic compound. WHO has highlighted the need for the study of cutaneous toxicity of PAT as manual labour is employed during pre and post harvest stages, thereby causing direct exposure to skin. In the present study cutaneous toxicity of PAT was evaluated following topical application to Swiss Albino mice. Dermal exposure of PAT, to mice for 4 h resulted in a dose (40-160 μg/animal) and time (up to 6 h) dependent enhancement of ornithine decarboxylase (ODC), a marker enzyme of cell proliferation. The ODC activity was found to be normal after 12 and 24 h treatment of patulin. Topical application of PAT (160 μg/100 μl acetone) for 24-72 h caused (a) DNA damage in skin cells showing significant increase (34-63%) in olive tail moment, a parameter of Comet assay (b) significant G 1 and S-phase arrest along with induction of apoptosis (2.8-10 folds) as shown by annexin V and PI staining assay through flow cytometer. Moreover PAT leads to over expression of p^21/WAF1 (3.6-3.9 fold), pro apoptotic protein Bax (1.3-2.6) and tumor suppressor wild type p⁵³ (2.8-3.9 fold) protein. It was also shown that PAT induced apoptosis was mediated through mitochondrial intrinsic pathway as revealed through the release of cytochrome C protein in cytosol leading to enhancement of caspase-3 activity in skin cells of mice. These results suggest that PAT has a potential to induce DNA damage leading to p⁵³ mediated cell cycle arrest along with intrinsic pathway mediated apoptosis that may also be correlated with enhanced polyamine production as evident by induction of ODC activity, which may have dermal toxicological implications.     

Dose-dependent effects of berberine on cell cycle pause and apoptosis in Balb/c 3T3 cells

In determining the morphological appearance of Balb/c 3T3 cells from berberine-treated (100 and 200 g/ml) cultures by light microscopy demonstrated that the high berberine concentration (200 g/ml) treatment was associated with the accumulation of numerous apoptotic cells, as identified by condensed nuclei and decrease in cell size. On the other hand, accumulation of cells in G₂/M phase instead of induction of apoptosis was observed after 48–72 h of 100 g/ml berberine treatment. Berberine was found mainly in cytoplasm during berberine-induced (100 g/ml) cell cycle G₂/M arrest, while it was highly concentrated in nuclei in the induction of apoptosis under high dose of berberine (200 g/ml) treatment. Further addition of berberine (100–200 g/ml) had little effect on the induction of apoptosis in the cells that had already been exposed to 100 g/ml of berberine for 48 h. Our results suggest that there may exist in Balb/c 3T3 cells an important threshold for regulation of cell cycle pause and induction of apoptosis, that is dose-dependent.     

Proteomic analysis of changes in the protein composition of MCF-7 human breast cancer cells induced by all-trans retinoic acid, 9-cis retinoic acid,and their combination

Retinoic acid (all-trans and 9-cis) isomers represent important therapeutic agents for many types of cancers, including human breast cancer. Changes in protein composition of the MCF-7 human breast cancer cells were induced by all-trans retinoic acid, 9-cis retinoic acid, and their combination and subsequently proteomic strategies based on bottom-up method were applied. Proposed approach was used for the analysis of proteins extracted from MCF-7 human breast cancer cell line utilizing a commercially manufactured kit RIPA and separated on two dimensional (2D) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) after treatment with both retinoic acid isomers. We found significant differences in occurrence of proteins probably affecting the cell migration process in tumour cells. Heat shock protein 27, ribonucleoprotein SmD3, and cofilin-1 were significantly upregulated after treatment with combination of individual retinoic acid isomers. On the other hand, AP-5 complex subunit beta-1 shows the different response. Thus, the results might help to find the answer to important medical questions on (i) the identification of signaling pathways affected by retinoic acid isomers or (ii) how the observed proteomic pattern might reflect the effectiveness of retinoic acids treatment.     

Effect of bisphenol-A on the expression of selected genes involved in cell cycle and apoptosis in the OVCAR-3 cell line

To support the argument that bisphenol-A (BPA) poses a risk for ovarian cancer, OVCAR-3 cell line was exposed to environmentally relevant concentration of BPA. Expression of selected genes involved in cell cycle and apoptosis were evaluated by real-time PCR. In a dose-dependent manner, BPA increased OVCAR-3 cell proliferation and decreased caspase-3 activity, but it had no effect on DNA fragmentation. We noted 1.2-1.5-fold induction of genes responsible for inducing cell proliferation and 1.2-46-fold suppression of genes responsible for inhibition of proliferation. Moreover, 1.6-8-fold suppression of genes involved in the extrinsic apoptotic pathway was observed. In parallel, 1.3-2.5-fold suppression pro-apoptotic genes and 1.6-51-fold induction of pro-survival genes involved in the intrinsic apoptotic pathway were observed. Additionally, 1.7-fold induction of p53 and 5-fold induction of endonuclease G genes involved in CAD-independent DNA fragmentation were noted under the influence of BPA.In conclusion, we hypothesize that induction of p53 and suppression of caspase-3 and 7 gene expression observed in this study activate the DNA repair process. Therefore, despite the observed induction of endo G gene expression, the action of BPA on DNA fragmentation was not observed.     

Roles of endogenous glutathione levels on 6-hydroxydopamine-induced apoptotic neuronal cell death in human neuroblastoma SK-N-SH cells

We investigated the roles of endogenous glutathione on 6-hydroxydopamine (6-OHDA)-induced apoptosis in human neuroblastoma SK-N-SH cells using DNA fragmentation enzyme-immunoassay and the DNA dye Hoechst 33258 staining. We observed that exogenous reduced glutathione (GSH), but not oxidized glutathione (GSSG), protected 6-OHDA (25 micro M)-induced apoptosis in a dose-dependent manner. Preincubation (18 h) with the glutathione synthesis inhibitor DL-buthionine-(S,R)-sulfoximine (BSO) significantly potentiated the toxic effects of 6-OHDA (12.5 or 25 micro M). In contrast to BSO, N-acetylcysteine (NAC) blocked, and L-(-)-cystine, the glutathione precursor, significantly attenuated 6-OHDA (25 micro M)-induced apoptosis, respectively. No alterations in endogenous glutathione concentrations were detected at 5, 15, 30, 60 min, 1 hour, 3 hours, or 6 hours after 6-OHDA (25 micro M) treatment. However, we found a 3.5-fold increase of intracellular glutathione levels 24 hours later. On the contrary, higher concentration (100 micro M) of 6-OHDA treatment, which caused more severe cell death, showed no changes of glutathione levels. These results suggest that delayed induction of endogenous glutathione might play an important role in the neuroprotective mechanism against dopamine cell death. In addition, we found that NAC might work as a beneficial catecholaminergic neuron-survival factor more efficiently than exogenous glutathione or L-cystine.     

Roles of chlorophyllin in cell proliferation and the expression of apoptotic and cell cycle genes in HB4a non-tumor breast cells

Chlorophyllin (Chl) has attracted interest in the scientific community due to its chemopreventive and antimutagenic properties. However, the molecular mechanisms of action of Chl remain unclear. This study assesses the effects on cell proliferation and the expression of genes involved in apoptosis, and the cell cycle in HB4a cells treated with Chl. Chl was cytotoxic and induced apoptosis to HB4a cells at 400?μg/mL. Analysis of gene expression showed that there was a decrease in the mRNA level of BIRC5 and CCNA2 genes involved in apoptosis and cell cycle progression, respectively. The proapoptotic gene BAX and the antiapoptotic genes BCL-2 and BCL-XL were upregulated. The cytotoxicity of Chl has been attributed to increases in the expression of BAX and decreases in the expression of genes involved in the cell cycle, but increases in the expression of anti-apoptotic genes suggests a mechanism for protection from cell death induced by Chl. This study provides important information about mechanisms that protect against or trigger damaging processes in non-tumor cells.