Journal Article

Decreased expression of glutathione <i>S</i>-transferase M1 in HPV16-transfected human cervical keratinocytes in culture

Chu Chen and Wilas Nirunsuksiri

in Carcinogenesis

Volume 20, issue 4, pages 699-703
Published in print April 1999 | ISSN: 0143-3334
Published online April 1999 | e-ISSN: 1460-2180 | DOI:
Decreased expression of glutathione S-transferase M1 in HPV16-transfected human cervical keratinocytes in culture

More Like This

Show all results sharing this subject:

  • Clinical Cytogenetics and Molecular Genetics


Show Summary Details


Glutathione S-transferase (GST) M1 is a member of the GST μ family of cytosolic enzymes that have been hypothesized to catalyze the conjugation of glutathione to a large number of hydrophobic substances, including carcinogens such as polynuclear aromatic hydrocarbons present in tobacco smoke, leading to their excretion. Epidemiologic and experimental evidence suggests that the risk of cervical cancer is related to both human papillomavirus (HPV) infection and cigarette smoking. We compared the enzymatic activities and mRNA levels of GSTs in GSTM1-positive human cervical keratinocytes (HCKs) that had been transfected with HPV16 with those in the parental cells. The GSTM1 activity toward the substrate trans-stilbene oxide was 5- to 7-fold lower than in the parental cells. The relative mRNA level in HCK transfected with HPV16 E6/E7, as quantified by reverse transcriptase–polymerase chain reaction (RT–PCR) with normalization against endogenous glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression, was 6% that of the parental cells. It was 16 and 82%, respectively, in cells that were transfected with HPV16 E6 alone or HPV16 E7 alone. When quantified by competitive RT–PCR using an exogenous nuclease-resistant synthetic cyclophilin RNA transcript as control, the mRNA level in HCK transfected with HPV16 E6 was ~10-fold lower that that in the parental cells. It was ~5- to 7-fold lower in the HPV16 E7 or HPV16 E6/E7 cells. Our results suggest that viral infections, through the modulation of cellular xenobiotic-metabolizing enzymes, may play a role in the ability of cells to handle environmental carcinogens.

Keywords: CDNB, 1-chloro-2,4-dinitrobenzene; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; GST, glutathione S-transferase; HCK, human cervical keratinocyte; HPV, human papillomavirus; KSFM, keratinocyte serum-free medium; PBS, phosphate-buffered saline; PCR, polymerase chain reaction; RT–PCR, reverse transcriptase–polymerase chain reaction; SDS, sodium dodecyl sulfate; SSC, sodium chloride–sodium citrate buffer; TSO, trans-stilbene oxide.

Journal Article.  5049 words.  Illustrated.

Subjects: Clinical Cytogenetics and Molecular Genetics

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.