The intra-nucleus integration of mitochondrial DNA (mtDNA)in cervical mucosa cells and its relation with c-myc expression.

Daozhen Chen,Jinying Xiang,Wenqun Xue

doi:10.1186/1756-9966-27-36

Daozhen Chen, Jinying Xiang + Show 1 more

Open Access

https://doi.org/10.1186/1756-9966-27-36

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Abstract

ObjectiveTo explore the relationship between the integration of mitochondrial DNA(mtDNA) in the nuclei of cervical epithelium cells and the expression of c-myc.MethodsThe expression of c-myc protein was measured by immunohistochemical test in 40 cases of the uterine cervix cancer, 30 cases of cervical intraepithelial neoplasia (CIN) and 30 cases of normal cervical epithelium; the sequence of mtDNA in the nuclei was detected by in situ hybridization technique.ResultsThe detection rates of mtDNA in the nuclei of cervical epithelium cells were 27.5%, 13.3% and 0% in cervical carcinoma, CIN, and normal cervical epithelium respectively. The expression rate of c-myc in cervical mucoma cells was 67% in the mtDNA sequence positive group and was significantly higher than that in the negative group (36%).ConclusionThe integration of mtDNA into the nuclei of cervical epithelium cells may be involved in the carcinogenesis of cervical epithelium cells and the expression of c-myc might be related to the integration of mtDNA sequence into nuclei of cervical epithelium cells.

Highlights

Several studies have found that point mutation of some tumors was relevant to that of mtDNA, but it is unclear for causal relation, which could not rule out the possibility of mtDNA integration to the nuclear genome and inducing carcinogenesis
The roles of mtDNA intranuclear integration could be as follows: (1) The integration fragments or integration sites do not influence the normal function of genome and have little impact on the biological characteristics of the host cells; (2) activation of a "healthy gene" enhances the body's disease resistance and promotes biological evolution; (3) oncogene activation or anti-oncogene inhibition causes cell proliferation and differentiation out of control, which leads to cancerization; (4) apoptosis gene activation or anti-apoptosis gene inhibition induces cells apoptosis rapidly
According to FIGO clinical staging standard, 13 cases were in stage I and 27 cases were in stage II; These cases were classified as histological grading standard: 9 cases in grade I, 21 cases in grade II and 11 cases in grade III. radical hysterectomy plus pelvic curettage of lymph node was performed for all these patients whose age ranged from 36 to 71 years old, and median age was 59.5 years old. 30 cases of cervical intraepithelial neoplasia (CIN) and 30 cases of normal cervical epithelia were taken as control

Summary

Introduction

Several studies have found that point mutation of some tumors was relevant to that of mtDNA, but it is unclear for causal relation, which could not rule out the possibility of mtDNA integration to the nuclear genome and inducing carcinogenesis. The roles of mtDNA intranuclear integration could be as follows: (1) The integration fragments or integration sites do not influence the normal function of genome and have little impact on the biological characteristics of the host cells; (2) activation of a "healthy gene" enhances the body's disease resistance and promotes biological evolution; (3) oncogene activation or anti-oncogene inhibition causes cell proliferation and differentiation out of control, which leads to cancerization; (4) apoptosis gene activation or anti-apoptosis gene inhibition induces cells apoptosis rapidly. More and more data indicated that mtDNA integration existed (page number not for citation purposes)

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Conclusion