Chromosomal microarray analysis for prenatal diagnosis of uniparental disomy: a retrospective study.

BACKGROUND: Chromosomal microarray analysis (CMA) is a valuable tool in prenatal diagnosis for the detection of chromosome uniparental disomy (UPD). This retrospective study examines fetuses undergoing invasive prenatal diagnosis through Affymetrix CytoScan 750 K array analysis. We evaluated both chromosome G-banding karyotyping data and CMA results from 2007 cases subjected to amniocentesis. RESULTS: The detection rate of regions of homozygosity (ROH) ≥ 10 Mb was 1.8% (33/2007), with chromosome 11 being the most frequently implicated (17.1%, 6/33). There were three cases where UPD predicted an abnormal phenotype based on imprinted gene expression. CONCLUSION: The integration of UPD detection by CMA offers a more precise approach to prenatal genetic diagnosis. CMA proves effective in identifying ROH and preventing the birth of children affected by imprinting diseases.

Case report: A case report and literature review of complete trisomy 9.

Complete trisomy 9 is a rare and lethal chromosomal anomaly characterized by multisystem dysmorphism and central nervous system (CNS) malformations. This study presents a case of complete trisomy 9 with an unusual phenotypic association and investigates the genetic pathways involved in this chromosomal abnormality. Trisomy 9 leads to a wide range of organ abnormalities, and this research contributes to a better understanding of the phenotype associated with this rare aneuploidy. The literature on the phenotypes of fetuses with various systems affected by complete trisomy 9 was reviewed and summarized. Correct diagnosis and appropriate counseling based on the characteristics of previous reports of fetuses with trisomy 9 is essential in maternity care and clinical management. To provide guidance and help for clinical diagnosis, this study aimed to explore the clinical and genetic characteristics of trisomy 9 syndrome to improve clinicians' understanding of the disease.

Fangchinoline Exerts Anticancer Effects on Colorectal Cancer Cells by Evoking Cell Apoptosis via Endoplasmic Reticulum Stress.

We studied the anti-tumor effect of fangchinoline (FAN) against human colorectal cancer cell lines CCL-244 and SW480 and analyzed the mechanism of FAN action. The cell viability and apoptosis were assessed by MTT test and Annexin V-PI staining; caspase-3 activity was measured by Western blotting. The expression of endoplasmic reticulum stress-related proteins was assessed by real-time PCR, Western blotting, and gene transfection. It was found that FAN inhibited cell growth and induced apoptosis in human colorectal cancer cell lines CCL-244 and SW480 in a dose-dependent manner. The caspase-3 inhibitor Ac-DEVD-CHO could reverse the inhibitory effect of FAN. Moreover, FAN significantly increased the expression of endoplasmic reticulum stress-related proteins p-PERK, p-eIF2α, ATF4, and CHOP in CCL-244 and SW480 cells. In addition, endoplasmic reticulum stress inhibitor 4-phenylbutyric acid or CHOP knockdown could prevent FAN-induced apoptosis. Thus, FAN induced apoptosis of human colorectal cancer through activation of endoplasmic reticulum stress.

CircRNA OXCT1 promotes the malignant progression and glutamine metabolism of non-small cell lung cancer by absorbing miR-516b-5p and upregulating SLC1A5.

Previous study has demonstrated the high expression of circular RNA 3-oxoacid CoA-transferase 1 (circ-OXCT1) in lung adenocarcinoma tumor tissues. However, the role and possible mechanism of circ-OXCT1 in non-small cell lung cancer (NSCLC) progression was unclear.Quantitative real-time PCR (qRT-PCR), western blotting and immunohistochemistry (IHC) staining assay were performed to detect the expression of circ-OXCT1, microRNA-516b-5p (miR-516b-5p), solute carrier family 1 member 5 (SLC1A5) and other indicated protein markers. Cell proliferation was measured by Cell counting kit 8 (CCK8), colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) assays. Flow cytometry was employed to detect the rate of apoptotic cells. Cell migration and invasion were measured using transwell assay. The relative glutamine uptake and α-ketoglutarate (α-KG) production was determined using commercial kits. Interaction between miR-516b-5p and circ-OXCT1 or SLC1A5 was predicted by bioinformatics analysis and confirmed via luciferase reporter and RNA immunoprecipitation (RIP) assays. In vivo assay was implemented to demonstrate the effect of circ-OXCT1 in tumor growth.Circ-OXCT1 and SLC1A5 were upregulated and miR-516b-5p was downregulated in NSCLC tissues and cells. Functional experiments revealed that circ-OXCT1 silencing suppressed cell proliferation, migration and invasion, but promoted cell apoptosis in vitro. Circ-OXCT1 knockdown repressed tumor formation in vivo. Besides, miR-516b-5p was a target of circ-OXCT1, and miR-516b-5p inhibitor could relieve circ-OXCT1 absence-mediated effects in NSCLC cells. SLC1A5 was identified as a target of miR-516b-5p. Circ-OXCT1 promoted SLC1A5 expression by target binding with miR-516b-5p.Circ-OXCT1 facilitated NSCLC progression via miR-516b-5p-dependent regulation of SLC1A5, which provided a possible circRNA-targeted therapy for NSCLC.

Detection of partial deletion and mosaicism using quantitative fluorescent polymerase chain reaction: Case reports and a review of the literature.

BACKGROUND: Aneuploidy of chromosomes 13, 18, 21, X, and Y can be detected by the quantitative fluorescence polymerase chain reaction (QF-PCR) performed with short tandem repeat (STR) markers. Although QF-PCR is designed to detect whole chromosome trisomy, the partial deletion or mosaic of chromosomes may also be detected. METHODS: Partial deletion or mosaic of chromosomes in three cases was detected by QF-PCR. Karyotyping and chromosome microarray analysis(CMA) were performed. We further reviewed the clinical utility of QF-PCR in detecting mosaicisms and deletions/duplications. RESULTS: QF-PCR demonstrated structurally abnormal 21, X, and Y chromosomes in primary amniotic cells. QF-PCR results in these three cases showed abnormal peak height/peak area, which could not be interpreted according to the kit instructions. QF-PCR results suggested that there were partial deletions or mosaicism, which were confirmed by karyotyping and CMA. CONCLUSION: In addition to detecting trisomies of whole chromosomes, QF-PCR can also detect deletion and mosaicism of chromosomes 13, 18, 21, X, and Y, which could suggest the presence of copy number variants (CNVs). Additional testing with genetic technologies, such as karyotyping or microarrays, is recommended when an uninformative pattern is suspected.

PARP-1 modulates the expression of miR-223 through histone acetylation to involve in the hydroquinone-induced carcinogenesis of TK6 cells.

The upstream regulators of microRNAs were rarely reported. Hydroquinone (HQ) is the main metabolite of benzene, one of the important environmental factors contributing to leukemia and lymphoma. In HQ-induced malignant transformed TK6 (TK6-HT) cells, the expression of PARP-1 and miR-223 were upregulated. When in PARP-1 silencing TK6-HT cells, miR-223 was downregulated and the apoptotic cell number correspondingly increased. In TK6 cells treated with HQ for different terms, the expression of miR-223 and PARP-1 were dynamically observed and found to be decreased and increased, respectively. Trichostatin A could increase the expression of miR-223, then the expression of HDAC1-2 and nuclear factor kappa B were found to be increased, but that of mH2A was decreased. PARP-1 silencing inhibited the protein expression of H3Ac, mH2A, and H3K27ac. By co-immunoprecipitation experiment, PARP-1 and HDAC2 were found to form a regulatory complex. In conclusion, we demonstrated that the upregulation of PARP-1 mediated activation of acetylation to promote the transcription of miR-223 possibly via coregulating with HDAC2, an epigenetic regulation mechanism involved in cell malignant transformation resulting from long-term exposure to HQ, in which course, H3K27ac might be a specific marker for the activation of histone H3, which also gives hints for benzene exposure research.

FISH-Based Karyotype Analyses of Four Dracaena Species.

The genus Dracaena is the main source of dragon's blood, which is a plant resin and has been used as traditional medicine since ancient times in different civilizations. However, the chromosome numbers and karyotypes present in this genus remain poorly understood. In this study, fluorescence in situ hybridization (FISH) using oligonucleotide probes for ribosomal DNAs (5S and 45S rDNA) and telomeric repeats (TTTAGGG)3 was applied to analyze 4 related species: Dracaena terniflora Roxb., Dracaena cambodiana Pierre ex Gagnep., Aizong (Dracaena sp.), and Dracaena cochinchinensis (Lour.) S.C. Chen. In all 4 species, both 5S and 45S rDNA showed hybridization signals in the paracentromeric region of a pair of chromosomes; the sizes of the 45S rDNA signals were larger than those of the 5S rDNA. Importantly, the telomeric repeat signals were located in the telomeric regions of almost all chromosomes. The results indicated that the chromosome number of all 4 Dracaena species is 2n = 40, and the lengths of the mitotic metaphase chromosomes range from 0.99 to 2.98 µm. Our results provide useful cytogenetic information, which will be beneficial to future studies in genome structure of the genus Dracaena.

Association of Obesity and Body Fat Percentage with Pubertal State in Six- to Nine-Year-Old Chinese Females.

Background: An early trend in the mean age of pubertal onset appears in adolescents, but the association between body fat percentage (BF%) of children and precocious puberty is unclear. The aim of the study was to analyze the association of sexual development with BF% in girls. Methods: A total of 407 females were included in this cross-sectional study. BF% was measured by Inbody S10, International Obesity Task Force was used to judge overweight or obesity, and early puberty was defined as a younger age than the median age in each of the pubertal Tanner stages. Logistic regression analysis was used to test relationships between pubertal states and independent variables, including age, weight, waist circumference (WC), type of school, and residency. Results: Females with early puberty exhibited higher anthropometry data (such as weight, BMI, BF%) than females with normal maturation (p < 0.001). Weight, BMI, WC, BF% residency, and school type were related to pubertal state (p < 0.001). Females with higher BF% were more likely to exhibit early puberty (odds ratio = 1.138, 95% confidence interval = 1.046-1.237). The students who lived in urban areas and studied in public schools had a lower risk of early puberty. Moreover, BF% continuously increased with age in 6- to 9-year-old girls. Conclusions: Females with higher BF% may be more likely to exhibit early puberty. In future studies, more research is needed to analyze this mechanism of how BF% influences puberty development.

miR-371b-5p promotes cell proliferation, migration and invasion in non-small cell lung cancer via SCAI.

OBJECTIVE: Multiple gene targets have been reported for treatment of non-small cell lung cancer (NSCLC), however, the accompanying genetic tolerance was reported increasingly. Therefore, it is important to find new biomarkers or therapeutic targets in treatment of NSCLC. METHODS: The expression levels of miR-371b-5p were detected by qRT-PCR in NSCLC tissues and cell lines. To evaluate the effect of miR-371b-5p on NSCLC progression, we first transfected the miR-371b-5p inhibitor for construction of the miR-371b-5p down-regulated cell model. Then the cell proliferation, migration, invasion and cell apoptosis were detected. In addition, the expression levels of adhesion factors were detected. The target gene of miR-371b-5p was identified by bioinformatics analysis, and rescue experiment was conducted to validate the effect of miR-371b-5p on proliferation, migration and invasion of NSCLC. RESULTS: Our findings revealed that the miR-371b-5p was overexpressed in NSCLC and could markedly promote the cell proliferation, migration and invasion. Expression levels of both intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly down-regulated when treated by miR-371b-5p inhibitor. Moreover, dual-luciferase reporter assay showed that the miR-371b-5p targeted SCAI in regulation of cell proliferation, migration and invasion, and the expression of miR-371b-5p was negatively associated with SCAI in NSCLC tissues and cell lines. Rescue experiment revealed that the miR-371b-5p could rescue the effect of SCAI on cell proliferation, migration and invasion. CONCLUSION: Our results suggest that the miR-371b-5p and SCAI may serve as novel prognostic biomarkers and therapeutic targets for NSCLC.

[The value of P16/ki67 double labeling, HPV E6/E7 mRNA detection and their combined application in cytological shunt diagnosis of low-grade squamous intraepithelial lesions].

Objective To explore the value of double labeling of P16/ki67, E6/E7 mRNA of human papillomavirus (HPV) and combined detection in shunt diagnosis of low-grade squamous intraepithelial lesions (LSIL) by thin-layer cervical cytology (TCT). Methods The study enrolled 239 patients who underwent colposcopy and biopsy within 4 weeks after primary TCT diagnosis. The remaining cytological samples were double-labeled with P16/ki67 immunocytochemical staining and the HPV E6/E7 mRNA was detected by Panther automatic HPV E6/E7 mRNA detection system. Using SPSS22.0 software, the positive rates of P16/ki67 double-labeling, HPV E6/E7 mRNA and combined detection were analyzed in different cervical lesions, and the positive rates in the same cervical lesions were compared horizontally to evaluate the efficiency of double labeling of P16/ki67, HPV E6/E7 and combined detection in the diagnosis of high-grade squamous intraepithelial lesions (HSIL) and above lesions. Results The diagnostic results of HE staining for the 239 cases of LSIL were 71 cases of chronic cervicitis (29.71%), 143 cases of LSIL (59.83%), 22 cases of HSIL (9.20%) and 3 cases of cervical cancer (1.26%). There were 46 cases of P16+ki67+ lesions (19.25%), 41 cases of ki67+P16- lesions (17.15%), 33 cases of ki67-P16+ lesions (13.81%) and 119 cases of P16-ki67- lesions (49.79%). The positive rates of P16/ki67 double-labeling, HPV E6/E7 mRNA and combined detection increased with the severity of cervical lesions. The positive rate of combined detection was the highest in the HSIL lesions, which was higher than that of P16/ki67 double-labeling and HPV E6/E7 mRNA detection. The sensitivity of combined detection was higher than that of P16/ki67 double-labeling and HPV E6/E7 mRNA detection. The Youden index of joint detection was 0.7850. Conclusion The combined detection of P16/ki67 double labeling, HPV E6/E7 mRNA and HPV E6/E7 mRNA had a certain clinical value in the management of cell LSIL shunt diagnosis. The combined detection significantly improved the sensitivity and Youden index of HSIL and above lesions, while maintaining a high specificity and coincidence rate.

Regulatory loop between lncRNA FAS-AS1 and DNMT3b controls FAS expression in hydroquinone-treated TK6 cells and benzene-exposed workers.

Hydroquinone (HQ), one of the main metabolites of benzene, is a well-known human leukemogen. However, the specific mechanism of how benzene or HQ contributes to the development of leukemia is unknown. In a previous study, we demonstrated the upregulation of DNA methyltransferase (DNMT) expression in HQ-induced malignant transformed TK6 (HQ-TK6) cells. Here, we investigated whether a regulatory loop between the long noncoding RNA FAS-AS1 and DNMT3b exists in HQ-TK6 cells and benzene-exposed workers. We found that the expression of FAS-AS1 was downregulated in HQ-TK6 cells and workers exposed to benzene longer than 1.5 years via histone acetylation, and FAS-AS1 expression was negatively correlated with the time of benzene exposure. Restoration of FAS-AS1 in HQ-TK6 cells promoted apoptosis and inhibited tumorigenicity in female nude mice. Interestingly, treatment with a DNMT inhibitor (5-aza-2-deoxycytidine), histone deacetylase inhibitor (trichostatin A), or DNMT3b knockout led to increased FAS-AS1 through increased H3K27ac protein expression in HQ-TK6 cells, and DNMT3b knockout decreased H3K27ac and DNMT3b enrichment to the FAS-AS1 promoter region, which suggested that DNMT3b and/or histone acetylation involve FAS-AS1 expression. Importantly, restoration of FAS-AS1 resulted in reduced expression of DNMT3b and SIRT1 and increased expression of FAS in both HQ-TK6 cells and xenograft tissues. Moreover, the average DNMT3b expression in 17 paired workers exposed to benzene within 1.5 years was decreased, but that of the remaining 103 paired workers with longer exposure times was increased. Conversely, DNMT3b was negatively correlated with FAS-AS1 expression. Both FAS-AS1 and DNMT3b influenced the enrichment of H3K27ac in the FAS promoter region by regulating the expression of SIRT1, consequently upregulating FAS expression. Taken together, these observations demonstrate crosstalk between FAS-AS1 and DNMT3b via a mutual inhibition loop and indicate a new mechanism by which FAS-AS1 regulates the expression of FAS in benzene-related carcinogenesis.

Investigation of RC-DTH air hammer performance using CFD approach with dynamic mesh method.

Reverse circulation down-the-hole (RC-DTH) air hammers have been widely used in construction and mining activities owing to their high drilling efficiency and good dust control performance. This paper presents a computational fluid dynamics (CFD) approach with the dynamic mesh method for evaluating the performance of RC-DTH air hammers. Nine stages of operating conditions of the RC-DTH air hammer are described herein to better understand the operating mechanism of the RC-DTH air hammer. Dynamic layering, sliding interfaces, as well as user-defined functions were employed to update the mesh in dynamic mesh modelling. The influences of rebound coefficient, input air pressure, and piston mass on the performance of RC-DTH air hammers were studied. It was found that increasing the rebound coefficient and input air pressure can improve the impact performance of RC-DTH air hammers, whereas increasing input air pressure can reduce energy efficiency and increase energy consumption. In addition, simulation results indicate that increasing the input air pressure may increase the stroke of the piston; the piston mass should be optimally selected to match the designed geometric parameters to avoid a significant drop in performance. The CFD approach with the dynamic mesh method shows superiority in evaluating the performance of RC-DTH air hammers.

Poly(ADP-ribose) polymerase-1 promotes expression of miR-155 by the up-regulation of methyl-CpG binding domain protein 2 in TK6 cells exposed to hydroquinone.

Hydroquinone (HQ), one of the major metabolites of benzene, can induce aberrant gene expression. MiR-155, a tumor activator, participates in various biological processes, including DNA damage response. However, the molecular mechanism of aberrant miR-155 expression is still not completely elucidated. Here, we investigated the mechanism of abnormal expression of miR-155 induced by poly(ADP-ribose)polymerase-1 (PARP-1) expression in HQ-treated TK6 lymphoblastoid cells. We examined the expression of genes related to abnormal expression of miR-155 to explore the reason for this phenomenon. The results of the present study showed that miR-155 was significantly increased and reactive oxygen species (ROS) were decreased in cells treated with HQ for 72 h compared with PBS-treated cells. Meanwhile, E4F1, PARP-1 and PARP-1 related co-regulators (NF-κB, HDAC1, and HDAC2), acetylated histone H3 (H3Ac) were increased in a concentration-dependent manner. Experiments for treatment with 5-AzaC (DNMTs inhibitor), TSA (HDACs inhibitor), DOX (to activate PARP-1) or MG132 (proteasome inhibitor) revealed that the MBDs and PARP-1 was positively associated with miR-155 expression. Moreover, in cells treated with HQ in conjunction with PARP-1 knockdown, expression of miR-155, H3Ac and MBD2 protein were decreased, compared with negative control. In conclusion, PARP-1 activates expression of miR-155 via acetylation by regulating MBD2 in TK6 cells exposed to HQ.

Serum Cystatin C Levels in Twin Pregnancy versus Singleton Pregnancy.

OBJECTIVE: To explore whether there was an increased secretion of cystatin C (Cys C) in twin pregnancy. METHODS: Patients with a total of 281 singleton pregnancies (including 38 patients with preeclampsia) and 72 twin pregnancies, as well as 42 patients who were not pregnant, were included in this study. We tested levels of serum Cys C, creatinine, and uric acid, along with the estimated glomerular filtration rate (eGFR), in different groups. RESULTS: The levels of serum Cys C in all 3 trimesters for women with twin pregnancy were much higher than those in the corresponding trimesters for women with singleton pregnancy. However, we observed little change in eGFR in the corresponding trimesters. Cys C/eGFR in the second and third trimester of twin pregnancy increased, compared with the corresponding trimesters of women with singleton pregnancy. Levels of serum Cys C were higher in the third trimester in women with twin pregnancy than that in patients with preeclampsia. Also, Cys C/eGFR in the third trimester of twin pregnancy was close to the level observed in patients with preeclampsia. CONCLUSIONS: Increased secretion of Cys C could contribute to the elevated serum Cys C levels that we observed in twin pregnancy.

E4F1 silencing inhibits the cell growth through cell-cycle arrest in malignant transformed cells induced by hydroquinone.

Hydroquinone (HQ), one of the most significant metabolic activation products of benzene in an organism, can cause hematological toxicity, such as acute myeloid leukemia. It is a clear carcinogen that can cause changes in the disorder of cell cycle and cell growth. However, its molecular mechanisms remain unclear. E4 transcription factor 1 (E4F1), an important transcription factor, participating in the regulation of cell cycle may be related to the occurrence of tumor. Here, we examined the HQ-induced malignant transformed TK6 cells (TK6-HT) to illustrate the role of E4F1 in carcinogenesis. The present study showed that both the expressions of E4F1 messenger RNA and protein increased obviously in TK6-HT, preliminarily indicating that E4F1 is associated with HQ-induced carcinogenesis. To further explore the role of E4F1, we established E4F1 silencing TK6-HT (pLVX-shE4F1) and its control cells (pLVX-shNC) using lentiviral short hairpin RNA (shRNA) interference expression plasmid vector pLVX-shRNA. Flow cytometry and cell counting kit-8 assay were used to determine the effects of E4F1 silencing on cell cycle and cell growth, respectively. E4F1 silencing inhibited cell growth in TK6-HT. The results from flow cytometry indicated that the inhibitory effect on cell growth may be the results of the E4F1 silencing-induced accumulation in G2/M compared with TK6-HT-shNC. Meanwhile, levels of DNA damage (γ-H2AX), proteins of Rb and phosphorylated Rb, and reactive oxygen species were increased in TK6-HT-shRNA2 cells, which is the critical reason of cell-cycle arrest. In conclusion, E4F1 silencing inhibits the cell growth through cell-cycle arrest in malignant transformed cells induced by HQ.

[Effects of Osthole on Apoptosis of HL-60 Cells Induced by TRAIL and Its Related Mechanism].

OBJECTIVE: To explore the effects of Osthole on apoptosis of HL-60 cells induced by tumor necrosis factor related apoptosis inducing ligand (TRAIL) and its possible mechanism. METHODS: The proliferative inhibition of HL-60 cells treated with different concentrations of Osthole, TRAIL alone and Osthole combined with TRAIL was measured by MTT assay. The HL-60 cells were treated with Osthole, TRAIL alone and Osthole combined with TRAIL at the concentration

miR-7-5p overexpression suppresses cell proliferation and promotes apoptosis through inhibiting the ability of DNA damage repair of PARP-1 and BRCA1 in TK6 cells exposed to hydroquinone.

Hydroquinone (HQ), one of the major metabolic products of benzene, is a carcinogen, which induces apoptosis and inhibit proliferation in lymphoma cells. microRNA-7-5p (miR-7-5p), a tumor suppressor, participates in various biological processes including cell proliferation and apoptosis regulation by repressing expression of specific oncogenic target genes. To explore whether miR-7-5p is involved in HQ-induced cell proliferation and apoptosis, we assessed the effect of miR-7-5p overexpression on induction of apoptosis analyzed by FACSCalibur flow cytometer in transfection of TK6 cells with miR-7-5p mimic (TK6- miR-7-5p). We observed an increased apoptosis by 25.43% and decreased proliferation by 28.30% in TK6-miR-7-5p cells compared to those negative control cells (TK6-shNC) in response to HQ treatment. Furthermore, HQ might active the apoptotic pathway via partly downregulation the expression of BRCA1 and PARP-1, followed by p53 activation, in TK6-miR-7-5p cells. In contrast, attenuated p53 and BRCA1 expression was observed in shPARP-1 cells than in NC cells after HQ treatment. Therefore, we conclude that HQ may activate apoptotic signals via inhibiting the tumor suppressive effects of miR-7-5p, which may be mediated partly by upregulating the expression of PARP-1 and BRCA1 in control cells. The increase of miR-7-5p expression further intensified downregulation of PARP-1 and BRCA1 in TK6-miR-7-5p cells, resulting in an increase of apoptosis and proliferation inhibited.

Bcl-2 protects TK6 cells against hydroquinone-induced apoptosis through PARP-1 cytoplasm translocation and stabilizing mitochondrial membrane potential.

B cell leukemia/lymphoma-2 (Bcl-2) suppresses apoptosis by binding the BH3 domain of proapoptotic factors and thereby regulating mitochondrial membrane potential (MMP). This study aimed to investigate the role of Bcl-2 in controlling the mitochondrial pathway of apoptosis during hydroquinone (HQ)-induced TK6 cytotoxicity. In this study, HQ, one metabolite of benzene, decreased the MMP in a concentration-dependent manner and induced the generation of reactive oxygen species (ROS), the activation of the DNA damage marker γ-H2AX, and production of the DNA damage-responsive enzyme poly(ADP-ribose)polymerase-1 (PARP-1). Exposure of TK6 cells to HQ leads to an increase in Bcl-2 and co-localization with PARP-1 in the cytoplasm. Inhibition of Bcl-2 using the BH3 mimetic, ABT-737, suppressed the PARP-1 nuclear to cytoplasm translocation and sensitized TK6 cells to HQ-induced apoptosis through depolarization of the MMP. Western blot analysis indicated that ABT-737 combined with HQ increased the levels of cleaved PARP and γ-H2AX, but significantly decreased the level of P53. Thus, ABT-737 can influence PARP-1 translocation and induce apoptosis via mitochondria-mediated apoptotic pathway, independently of P53. In addition, we found that knockdown of PARP-1 attenuated the HQ-induced production of cleaved PARP and P53. These results identify Bcl-2 as a protective mediator of HQ-induced apoptosis and show that upregulation of Bcl-2 helps to localize PARP-1 to the cytoplasm and stabilize MMP. Environ. Mol. Mutagen. 59:49-59, 2018. © 2017 Wiley Periodicals, Inc.