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Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells.
Toxicology. 2009 Aug 03; 262(2):153-61.T

Abstract

T-2 toxin is the most toxic trichothecene and both humans and animals suffer from several pathological conditions after consumption of foodstuffs contaminated with trichothecenes. We investigated the molecular mechanism of T-2 toxin induced cytotoxicity and cell death in HeLa cells. T-2 toxin at LC50 of 10 ng/ml caused time dependent increase in cytotoxicity as assessed by dye uptake, lactatedehydrogenase leakage and MTT assay. The toxin caused generation of reactive oxygen species as early as 30 min followed by significant depletion of glutathione levels and increased lipid peroxidation. The results indicate oxidative stress as underlying mechanism of cytotoxicity. Single stranded DNA damage after T-2 treatment was observed as early as 2 and 4h by DNA diffusion assay. The cells exhibited apoptotic morphology like condensed chromatin and nuclear fragmentation after 4h of treatment. Downstream of T-2 induced oxidative stress and DNA damage a time dependent increase in expression level of p53 protein was observed. The increase in Bax/Bcl2 ratio indicated shift in response, in favour of apoptotic process in T-2 toxin treated cells. Western blot analysis showed increase in levels of mitochondrial apoptogenic factors Bax, Bcl-2, cytochrome-c followed by activation of caspases-9, -3 and -7 leading to DNA fragmentation and apoptosis. In addition to caspase-dependent pathway, our results showed involvement of caspase-independent AIF pathway in T-2 induced apoptosis. Broad spectrum caspase inhibitor z-VAD-fmk could partially protect the cells from DNA damage but could not inhibit AIF induced oligonucleosomal DNA fragmentation beyond 4 h. Results of the study clearly show that oxidative stress is the underlying mechanism by which T-2 toxin causes DNA damage and apoptosis.

Authors+Show Affiliations

Division of Pharmacology and Toxicology, Defence Research and Development Establishment, Jhansi Road, Gwalior 474002, India.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19524637

Citation

Chaudhari, Manjari, et al. "Oxidative Stress Induction By T-2 Toxin Causes DNA Damage and Triggers Apoptosis Via Caspase Pathway in Human Cervical Cancer Cells." Toxicology, vol. 262, no. 2, 2009, pp. 153-61.
Chaudhari M, Jayaraj R, Bhaskar AS, et al. Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells. Toxicology. 2009;262(2):153-61.
Chaudhari, M., Jayaraj, R., Bhaskar, A. S., & Lakshmana Rao, P. V. (2009). Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells. Toxicology, 262(2), 153-61. https://doi.org/10.1016/j.tox.2009.06.002
Chaudhari M, et al. Oxidative Stress Induction By T-2 Toxin Causes DNA Damage and Triggers Apoptosis Via Caspase Pathway in Human Cervical Cancer Cells. Toxicology. 2009 Aug 3;262(2):153-61. PubMed PMID: 19524637.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Oxidative stress induction by T-2 toxin causes DNA damage and triggers apoptosis via caspase pathway in human cervical cancer cells. AU - Chaudhari,Manjari, AU - Jayaraj,R, AU - Bhaskar,A S B, AU - Lakshmana Rao,P V, Y1 - 2009/06/12/ PY - 2009/04/08/received PY - 2009/05/31/revised PY - 2009/06/02/accepted PY - 2009/6/16/entrez PY - 2009/6/16/pubmed PY - 2009/7/29/medline SP - 153 EP - 61 JF - Toxicology JO - Toxicology VL - 262 IS - 2 N2 - T-2 toxin is the most toxic trichothecene and both humans and animals suffer from several pathological conditions after consumption of foodstuffs contaminated with trichothecenes. We investigated the molecular mechanism of T-2 toxin induced cytotoxicity and cell death in HeLa cells. T-2 toxin at LC50 of 10 ng/ml caused time dependent increase in cytotoxicity as assessed by dye uptake, lactatedehydrogenase leakage and MTT assay. The toxin caused generation of reactive oxygen species as early as 30 min followed by significant depletion of glutathione levels and increased lipid peroxidation. The results indicate oxidative stress as underlying mechanism of cytotoxicity. Single stranded DNA damage after T-2 treatment was observed as early as 2 and 4h by DNA diffusion assay. The cells exhibited apoptotic morphology like condensed chromatin and nuclear fragmentation after 4h of treatment. Downstream of T-2 induced oxidative stress and DNA damage a time dependent increase in expression level of p53 protein was observed. The increase in Bax/Bcl2 ratio indicated shift in response, in favour of apoptotic process in T-2 toxin treated cells. Western blot analysis showed increase in levels of mitochondrial apoptogenic factors Bax, Bcl-2, cytochrome-c followed by activation of caspases-9, -3 and -7 leading to DNA fragmentation and apoptosis. In addition to caspase-dependent pathway, our results showed involvement of caspase-independent AIF pathway in T-2 induced apoptosis. Broad spectrum caspase inhibitor z-VAD-fmk could partially protect the cells from DNA damage but could not inhibit AIF induced oligonucleosomal DNA fragmentation beyond 4 h. Results of the study clearly show that oxidative stress is the underlying mechanism by which T-2 toxin causes DNA damage and apoptosis. SN - 1879-3185 UR - https://www.unboundmedicine.com/medline/citation/19524637/Oxidative_stress_induction_by_T_2_toxin_causes_DNA_damage_and_triggers_apoptosis_via_caspase_pathway_in_human_cervical_cancer_cells_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0300-483X(09)00290-X DB - PRIME DP - Unbound Medicine ER -