Professor of Oncology, Department of Cancer Genetics
Roswell Park Cancer Institute
Elm and Carlton Streets
Buffalo, NY 14263
Telephone: (716) 845-8017
Fax:            (716) 845-1047
E-mail:        keshav.singh@roswellpark.org

General Research Interests

Mitochondrial oxidative stress, genomic instability and its role in breast cancer

Current Program

* Mitochondria-to-nucleus communication and its role in breast cancer
* Global response to oxidative stress and its role in cancer
* Mechanisms of mitochondria-mediated-mutator phenotype
* Oxidative damage and its repair in the nucleus and the mitochondria

Laboratory Personnel

Graduate Students

Brandon Hall, B.S. Graduate Student
Gretchka Mair, B.S. Graduate Student
Kelly Burke, B.S. Graduate Student
Claus Dresler, M.S. Visiting Graduate Student
Sheila Figel BS, Graduate Student


Description of Research

 

With the exception of peripheral red blood cells, mitochondria are present in all eukaroytic cells in varying numbers, from hundreds to thousands. Mitochondria perform multiple cellular function and are the major source of cellular energy and of reactive oxygen species (ROS). It is estimated that human cells produce up to 10 million ROS/mitochondrion/day. In mitochondria, the ROS are formed by the univalent reduction of molecular oxygen that is mediated by reactive compounds such as semi-ubiquinone, which are involved in electron transport chain. ROS cause oxidative stress, mutations, and promote tumor formation and progression. The growth promoting effects of oxidative stress in cancer is due to oxidative stress responsive signal transduction. Oxidative stress is also implicated in aging, and many diseases including heart, lung and neurodegenerative diseases.

The long-term goal of our laboratory is to understand the mechanisms of mitochondria mediated oxidative stress, genomic instability and its role in cancer. Currently, research in the laboratory is focused on identifying pathway(s) that protect cells from mitochondrial oxidative stress and genomic instability of both the mitochondrial and nuclear genomes. We are also conducting experiments to identify genes that are involved in monitoring the functional state of mitochondria and transducing signals from dysfunctional mitochondria to the nucleus (Mitochondria-to-Nucleus communication). These studies employ the unicellular eukaryote Saccharomyces cerevisiae yeast, mouse, and mammalian cell culture model systems to study these processes. Environmental carcinogens, pharmacological and chemotherapeutic agents are used to induce oxidative stress and genomic instability. Our approach uses both molecular and genetic methods in concert: molecular assays are used to detect and characterize genes of interest and in vivo function of the proteins is assessed by genetic analysis. In addition to understanding basic mechanisms, we have taken a multidisciplinary translational approach to identify molecular markers of oxidative stress involved in detection, diagnosis and treatment of cancer and other oxidative stress related diseases.

Described below are the ongoing projects in my laboratory

1) Genetics of mitochondria-to-nucleus communication in human breast epithelial cells and its role in breast cancer: We have determined the global gene expression profile in response to loss of mitochondrial function in breast epithelial cells. This project investigates the role of identified genes in primary breast cancer. Currently we are investigating the function of one such protein called BACH1 (BRCA1 interacting protein) involved in mitochondria-mediated nuclear genomic instability and its role in breast cancer.

2) Genetics of mitochondria-to-nucleus communication in yeast cells: This project investigates the genes and mechanisms involved in monitoring the functional state of mitochondria, the major site of ROS production. We have used cDNA microarray to determine the global gene expression profile in response to loss of mitochondrial function and are currently investigating the pathways that protect cells from mitochondria-mediated nuclear mutator phenotype.

3) Global response to oxidative stress in Saccharomyces cerevisiae: We have determined the in vivo genetic targets of superoxide induced oxidative stress. We are now investigating the global mechanisms of adaptation to oxidative stress that leads to genomic instability. This project uses genetic and biochemical approaches to identify pathways involved in oxidative DNA damage and repair in the mitochondria and in the nucleus of yeast S. cerevisiae.

4) Genetic instability in human epithelial cells: Investigates the mechanisms of spontaneous or induced (by carcinogens and cancer therapeutic agents) mitochondrial and nuclear genome mutagenesis in human breast epithelial cell culture model. This project uses genetic and biochemical approaches to define the mechanisms involved in oxidative DNA damage and repair in the mitochondria and in the nucleus of mammary epithelial cells.

Key Publications

• Katrangi E, D'Souza G, Boddapati SV, Kulawiec M, Singh KK, Bigger B, Weissig V, Xenogeneic transfer of isolated murine mitochondria to human þ°cells can improve respiratory function.  Rejuvenation Res, In press
• Verma M, Naviaux RK, Tanaka M, Jumar D, Franceschi C, Singh KK.  Meeting report:  Mitochondrial DNA and cancer epidemiology.  Cancer Res 2007; 67(2):437-439.
• Vujcic M, Shroff M, Singh KK.  Genetic determinants of mitochrondrial response to arsenic in yeast Saccharomyces Cerevisiae.  Cancer Res 2007; 67(20): 9740-9749.
• Desler C, Munch-Petersen B, Stevnsner T, Matsui SI, Kulawiec M, Singh KK, Rasmussen LJ.  Mitochondria as a determinant of nucleotide pools and chromosomal ability.  Mutat Res 2007; 625(1-2)112-124.
• Weinberger M, Feng L, Paul A, Smith DL JR, Hontz RD, Smith JS, Vujcic M, Singh KK, Huberman JA, Burhans WC.  DNA replication stress is a determinant of chronological lifespan in budding yeast.  PLoS ONE 2007; 2:1:e748.
• Modica-Napolitano JS, Kulawiec M, Singh KK.  Mitochondria and human cancer.  Curr Mol Med 2007; 7(1):121-131.
• Singh KK.  Mitochondria damage checkpoint, aging and cancer.  Ann NY Acad Sci 2006; 1067:182-190.
• Zhang H, Chatterjee A, Singh KK. Saccharomyces cerevisiae polymerase ζ functions in mitochondria. Genetics 2006; 171:2683-2688.
• Kulawiec M, Arnouk H, Desouki M, Kazim L, Still I, Singh KK. Proteomic analysis of proteins involved in mitochondria-to-nucleus retrograde response in human cancer cells. Cancer Biol Ther 2006; 8:9657-9875.
• Singh KK, Desouki M, Franklin RB, Costello LC.  Mitochondrial aconitase and citgrate metabolism in malignant and nonmalignant human prostate tissues.  Mol Cancer 2006; 5(1):14.
• Desouki MM, Kulawiec M, Bansal S, Das GM, Singh KK. Cross talk between mitochondria and superoxide generating NADPH oxidase in breast and ovarian tumors. Cancer Biol Therap 2005; 4(12):1367-1373.
• Gourley PL, Hendricks JK, McDonald AE, Copeland RG, Barrett KE, Gourley CR, Singh KK, Naviaux RK. Mitochondrial correlation microscopy and nanolaser spectroscopy - new tools for biophotonic detection of cancer in single cells. Technol Cancer Res Treat 2005; 6:585-592.
• Singh KK. Nanotechnology in cancer detection and treatment. Technol Cancer Res 2005; 4:583-584.
• Franklin RB, Feng P, Milon B, Desouki MM, Singh KK, Kajdacsy-Balla A, Bagasra O, Costello LC. hZIP1 zinc uptake transporter down regulation and zinc depletion in prostate cancer. Mol Cancer 2005; 4:32.
• Singh KK, Kulaweic M, Still I, Desouki MM, Geradts, Matsui S-I. Inter-genomic cross talk between mitochondria and the nucleus plays an important role in tumorigenesis. Gene 2005; 354-140-146.
• Ambrosone CB, Ahn J, Singh KK, Rezashiraz H, Furberg H, Sweeney C, Coles B, Trovato A. Polymorphisms in genes related to oxidative stress (MPO, MnSOD, CAT) and survival after treatment for breast cancer.  Cancer Res 2005; 65:1105-1111.
• Park SY, Choi B, Cheon H, Pak YK, Kulawiec M, Singh KK, Lee MS. Cellular aging of mitochondrial DNA-depleted cells. Biochem Biophys Res Commun 2004; 4:325:1399-1405.
• Mori N, Delsite R, Natarajan K, Bhujwalla ZM, Singh KK. Loss of p53 function in colon cancer cells results in increased phosphocholine and total choline. Molec Imaging 2004; 3:319-323.
• Kachhap S, Singh KK. Expression of uracil glycosylase inhibitor in mitochondria is not mutagenic. Molecular Cancer 2004; 3:32-36.
• Singh KK. Mitochondrial dysfunction is a common phenotype in aging and cancer. Ann NY Acad Sci 2004; 1019:260-264
• Singh KK, Rasmussen AK, Rasmussen LJ. Genome wide analysis of signal transducers and regulators of mitochondrial dysfunction in S. cerevisiae Ann NY Acad Sci 2004; 1011:284-298.
• Zhou S, Kachhap S, Singh KK. Mitochondrial impairment in p53 deficient human cancer cells. Mutagenesis 2003; 18:287-292.
• Singh KK, Luccy BM, Zullo SJ. Mitochondria, Oxidative Stress and Mitochondrial Diseases. In: Oxidative Stress and Aging: Advances in Basic Science, Diagnostics, and Intervention. World Scientific Publishing Company, New York, NY, 2003; pp 452-466.
• Rasmussen AK, Chatterjee A, Rasmussen LR, Singh KK. Mitochondria-mediated mutator phenotype in Saccharomyces cerevisiae. Nucleic Acid Res 2003; 31:3909-3917.
• Kim G, Sikder H, Singh KK. A colorimetric method identifies the vulnerability of mitochondria to oxidative damage. Mutagenesis 2002; 17:375-381.
• Napolitano J, and Singh KK. Mitochondria as targets for detection and treatment of cancer. Expert Reviews in Molecular Medicine. 11 April, http://www-ermm.cbcu.cam.ac.uk/02004453h.htm, 2002.
• Delsite RD, Kachhap S, Anbazhagan R, Gabrielson E, Singh KK. Nuclear genes involved in mitochondria-to-nucleus communication in breast cancer cells, Molec Cancer 2002; 1:6-15.
• Jager AC, Rasmussen M, Bisgaard HC, Singh KK, Nielsen FC, Rasmussen LJ. HNPCC Mutations in the Human DNA Mismatch Repair Gene hMLH1 Influence Assembly of hMutL and hMLH1-hEXO1 Complexes. Oncogene 2001; 20:3590-3595.
• Singh KK, Sigala B, Sikder HA, Kim G, Schwimmer C. Inactivation of Saccharomyces cerevisiae OGG1 gene leads to increase frequency of mitochondrial deletions. Nucleic Acid Res 2001; 29:1381-1388.
• Parker A, Gu Y, Mahoney W, Suk-Hee L, Singh KK, Lu A. Human homolog of the MutY repair protein (hMYH) physically interacts with proteins involved in long-patch DNA base excision repair. J Biol Chem 2001; 276:5547-5555.
• Chatterjee A, and Singh KK. Uracil-DNA glycosylase deficient yeast exhibits a mitochondrial mutator phenotype. Nucleic Acid Res 2001; 29:4935-4940.
• Naviaux R, and Singh KK. Manipulations of the mitochondrial germ line must be openly debated and followed up. Nature 2001; 413:347.
• Singh KK. The Saccharomyces cerevisiae Sln1p-Ssk1p two-component system mediates response to oxidative stress and in an oxidant specific fashion. Free Rad Biol Med 2000; 29:1043-1050.
• Singh KK, Russell J, Sigala B, Zhang Y, Williams JR, Keshav KF. Mitochondrial DNA determines the cellular response to cancer therapeutic agents. Oncogene 1999; 18:6641-6646.
• Singh KK. Mitochondrial DNA mutations in Aging, Disease, and Cancer. Springer, New York, NY, 1998.