Alterations in keratins and associated proteins during 4-Nitroquinoline-1- oxide induced rat oral carcinogenesis

Deepak Kanojia*, Sharada Sawant, Anita Borges, Arvind Ingle, Milind Vaidya

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Background: Oral squamous cell carcinoma (OSCC) is the sixth largest group of malignancies globally and the single largest group of malignancies in the Indian subcontinent. Despite the advances in treatment and therapeutic modalities the five year survival rate of OSCC has not changed in the last few decades, and remains less than 40%. Several studies have focused on defining molecular markers that can either detect cancer at an early stage or can predict patient′s outcome. However, such markers are still undefined. Keratins (K) are epithelia predominant intermediate filament proteins which are expressed in a differentiation dependent and site specific manner. Keratins are being used as biomarkers in different epithelial disorders including cancer. They are associated with desmoplakin and 6β4 integrin which are components of desmosomes and hemidesmosomes respectively. Materials and Methods: 4-Nitroquinoline 1-Oxide (4NQO) was used as a carcinogen for the development of various stages of oral carcinogenesis in rat lingual mucosa. Two-Dimentional gel electrophoresis was performed for the separation of Keratins followed by western blotting for their specific identification. Western blotting and RT PCR was carried out for desmoplakin and 6β4 integrin respectively to understand their levels. Immunohistochemical analysis was carried out to further study the localization of desmoplakin and 6 integrin. Results: In this study we have analysed the alterations in Keratins and associated proteins during sequential stages of 4NQO induced rat oral carcinogenesis. Our results showed that the alterations primarily begin after the dysplastic changes in the lingual epithelium like the elevation of Keratins 5/6a, ectopic expression of Keratin 8, increase in suprabasal expression of 6 integrin and increase in desmoplakin levels. Most of these alterations persisted till the development of SCC except desmoplakin, the levels of which were downregulated in papillomatous lesions and SCC. Many of these alterations have also been documented in human oral carcinogensis. Conclusion: Thus, 4NQO model of rat lingual carcinogenesis reproduces majority of the changes that are seen in human oral carcinogenesis and it can be exploited for the development of biomarkers.

Original languageEnglish (US)
Article number14
JournalJournal of Carcinogenesis
StatePublished - 2012


  • 4-Nitroquinoline-1-oxide
  • 6β4 integrin
  • Biomarkers
  • Desmoplakin
  • Keratin
  • Rat oral carcinogenesis
  • Squamous cell carcinoma

ASJC Scopus subject areas

  • Oncology
  • Cancer Research
  • Health, Toxicology and Mutagenesis


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