Ajit Kumar Professor of Biochemistry and Molecular Medicine Professor of Microbiology, Immunology, and Tropical Medicine (Secondary) Office Phone: 202-994-2919 Email: Department: Biochemistry and Molecular Medicine

Education

• PhD, University of Chicago, 1968

Research

MicroRNAs (miRNAs), among the non-protein coding transcripts have received most attention because of their role in post-transcriptional gene silencing. Perturbations in miRNA expression has emerged as markers of disease progression, including human cancer. Our studies indicate that hepatitis C virus (HCV) replication relies on miRNA-141 (miR-141) directed translational suppression of DLC1 (DLC1 tumor suppressor, a Rho-type GTPase-activating protein); DLC1 is frequently deleted in hepatocellular carcinoma and other epithelial tumors. Dependence of HCV replication on oncogenic miRNAs (miR-141), also called ‘oncomirs’, shares a common theme of targeting DLC1 tumor suppressor in other epithelial cancers. Our recent studies built on the in vitro cell culture studies of HCV replication in human primary hepatocytes to a mouse model of HCV-infection induced liver tumor in human hepatocyte engrafted MUP-uPA/SCID/bg mice, to focus on functional validation of oncomir-regulated genes in the development of hepatocellular carcinoma. Results suggest that HCV-infection induced oncogenic changes stem from targeting PTEN tumor suppressor, the second (only to p53) most commonly targeted tumor suppressor gene in human cancer. The development of HCV-infection associated hepatocellular carcinoma (HCC) relies on suppression of essential tumor suppressors whose target genes would serve as prognostic markers of HCC.  

Publications

View publications by this faculty member from January 1, 2013 - present

MicroRNA in HCV infection and liver cancer. Kumar, Ajit. Biochemica et Biophysica Acta 1809 (2011), pp. 694-699.

MicroRNA Silencing of Tumor Suppressor DLC-1 Promotes Efficient Hepatitis C Virus Replication in Primary Human Hepatocytes. Banaudha, Krishna; Kaliszewski, Michael; Korolnek, Tamara; Florea, Liliana; Yeung, Man Lung; Jeang, Kuan-The; Kumar, Ajit. Hepatology Vol. 53, No. 1 2011, pp. 53-61.

Primary Hepatocyte Culture Supports Hepatitis C Virus Replication: A Model for Infection-Associated Hepatocarcinogenesis. Banaudha, Krishna; Orenstein, Jan M.; Korolnek, Tamara; St. Laurent III, George C.; Wakita, Takaji; Kumar, Ajit. Hepatology, Vol. 51, No. 6 2010. Pp. 1922-1932.

Additional publications published before January 1, 2013 may be available within Himmelfarb Library's database.

Industry Relationships and Collaborations

This faculty member (or a member of their immediate family) has reported a financial interest with the healthcare related companies listed below. These relations have been reported to the University and, when appropriate, management plans are in place to address potential conflicts.

• None