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Saleem A. Khan, PhD

Dr. Saleem Khan


Fax: 412-624-1401
520 Bridgeside Point II
450 Technology Drive


PhD in Biochemistry, Indian Institute of Science, Bangalore (India)

Academic Affiliation(s)

Professor, Department of Microbiology and Molecular Genetics

Member, University of Pittsburgh Cancer Institute

Affiliate, Center for Vaccine Research, University of Pittsburgh

Member, Molecular Virology and Microbiology Graduate Program

Member, Molecular Genetics and Developmental Biology Graduate Program


My laboratory is studying the roles of microRNAs in HPV-associated cervical and head & neck cancers. We have found that the miRNA expression profiles in HPV-positive squamous cell carcinoma of the head and neck (SCCHN) cell lines and tissues are distinctively different from those of HPV-negative SCCHN and normal oropharyngeal tissue. We have also shown that the E6 oncogene of HPV-16 upregulates the expression of miR-363 and downregulates the expression of miR-218 in HPV-positive SCCHN cell lines. Furthermore, miR-363 is also upregulated in HPV-positive SCCHN tumor tissues. We have also shown previously that the E6 oncogene of high-risk HPVs such as types 16 and 18, but not that of low-risk HPVs such as type 6, downregulates the expression of miR-218 in cervical cancer cells. Our ongoing studies deal with the identification of the mechanisms by which E6 affects miR-363 and miR-218 expression and whether these effects are p53-dependent. We are investigating whether epigenetic processes such as DNA methylation and histone modifications are involved in E6-mediated regulation of these miRNAs. We are also testing whether miR-363 and miR-218 are oncogenic and tumor suppressor miRNAs, respectively, that affect cell proliferation, migration, invasion, adhesion and apoptosis. We are also studying the potential role of miRNAs in aging, using the XFE syndrome as a model system. Using fibroblasts from wild-type and progeroid mice, we have identified several miRNAs whose expression is altered in the ERCC1 progeroid mice. We have also found that the expression of several of these miRNAs is similarly affected in the tissues from the ERCC1 mutant mice. We are currently testing whether the aging-related miRNAs promote cellular senescence. We are also studying the role of PcrA helicase, an essential protein in Gram-positive bacteria, in plasmid replication and cellular DNA metabolism. We have shown that the PcrA helicases of S. aureus, B. anthracis, S. pneumoniae and B. cereus are multifunctional proteins that have ATPase, DNA binding, translocation and helicase activities. Recently, using biochemical and single-molecule approaches we have shown that PcrA blocks homologous DNA recombination in vitro by displacing the RecA protein bound to the DNA. A major current focus of the laboratory is to identify the biochemical activities of PcrA that make it an essential protein in S. aureus.

Lab Personnel

Dr. Parvez Akhtar, Research Associate
Celia Munko, Senior Research Specialist

Areas of Interest

Role of microRNAs in human papillomavirus-associated cancers & in aging; PcrA helicase


Fagerburg M. V, Schauer G. D, Thickman K. R, Bianco P. R, Khan S. A, Leuba S. H, and Anand S. P. PcrA-mediated disruption of RecA nucleoprotein filaments--essential role of the ATPase activity of RecA. Nucleic Acids Res. 40: 8416-8424. |  View Abstract

McBee W. C, Gardiner A. S, Edwards R. P, Lesnock J. L, Bhargava R, Austin R. M, Guido R. S, and Khan S. A. MicroRNA Analysis in Human Papillomavirus (HPV)-Associated Cervical Neoplasia and Cancer. J Carcinogene Mutagene 1:114. doi:10.4172/2157- 2518.1000114 |  View Abstract

Wald A. I, Hoskins E. E, Wells S. I, Ferris R. L, and Khan S. A. Alteration of microRNA profiles in squamous cell carcinoma of the head and neck cell lines by human papillomavirus. Head Neck. 33: 504-512. |  View Abstract

Ueda R, Kohanbash G, Sasaki K, Fujita M, Zhu X, Kastenhuber E. R, McDonald H. A, Potter D. M, Hamilton R. L, Lotze M. T, Khan S. A, Sobol R. W, and Okada H. Dicer-regulated microRNAs 222 and 339 promote resistance of cancer cells to cytotoxic T-lymphocytes by down-regulation of ICAM-1. Proc Natl Acad Sci USA. 106: 10746-10751. |  View Abstract

Martinez I, Gardiner A. S, Board K. F, Monzon F. A, Edwards R. P, and Khan S. A. Human papillomavirus type 16 reduces the expression of microRNA-218 in cervical carcinoma cells. Oncogene. 27: 2575-2582. |  View Abstract

Martinez I, Wang J, Hobson K. F, Ferris R. L, and Khan S. A. Identification of differentially expressed genes in HPV-positive and HPV-negative oropharyngeal squamous cell carcinomas. Eur J Cancer. 43: 415-432. |  View Abstract

Yablonska S, Hoskins E. E, Wells S. I, and Khan S. A. Identification of microRNAs dysregulated in human foreskin keratinocytes (HFKs) expressing the human papillomavirus (HPV) type 16 E6 and E7 oncoproteins. MicroRNA doi:2211-5366/12 [In press]