Human Health Sciences

Texas Tech university Department of Environmental Toxicology, Human Health Sciences

The primary objectives of the Division of Human Health Sciences are to study etiological role of various environmental toxicants in pathogenesis of acute and chronic human diseases, to determine adverse effects of environmental toxicants on humans, and to design effective prevention strategies for reducing human diseases risks linked to exposure to environmental toxicants.

Major approaches used by members of the Division include:

Development of sensitive methods to detect environmental toxicants in human body fluids for assessing human diseases risks;
Development of various animal and human cell models for studying potential molecular mechanisms of known human diseases related to exposure to environmental toxicants;
Validation of molecular biomarkers for environmental toxicants in high-risk human populations;
Study of modulative effects of various agents, especially natural products, on prevention of toxicants-caused human diseases; and
Epigenetics and gene-environment interactions in human cancer development

Biostatistical Studies

Lead By:
Dr. Degeng Wang
Dr. Sun Hee Yim

A significant component of the work being done within the Human Health Sciences group involves the investigation, development, and application of rigorous statistical methodologies to the data being collected as part of our human health studies. Specific areas of interest are; 1) the development of rigorous study design protocols, 2) the application of mixed-effects models to epidemiological data, 3) the development of novel techniques for analyzing data from various "omics" approaches, 4) the utility of nonparametric approaches to a variety of epidemiological study designs, and 5) the application of information-theoretic approaches to human health data. Our research group embraces the view that biostatistics (and science in general) will benefit from a reduced emphasis on concepts such as "significant/nonsignificant." Estimation of effect sizes and confidence intervals, as well as the development of tools to address hypotheses directly related to specific biological questions of interest, may provide more insight and scientific understanding of the processes affecting human health.

Biotoxin Studies

Lead By:
Dr. Ernest Smith

The long-term goal of this research team is to investigate mechanisms of combinative toxic effects of biotoxin mixture(s) on animal and humans and develop prevention strategies against potential use of these mixture(s) as biological warfare threats (BWT) or terrorist attacks. The research has been

supported by RDECOM/DOD for six years with two phases of work: phase one focused on studying acute toxicity of various biotoxin mixtures in animal and human cell models and to develop methods to detect these biotoxin mixtures in environmental samples and biological fluids. Phase two focused on studying molecular mechanisms of combinative acute toxic effects of biotoxin mixtures in animal and human cell models with emphasis on cell signaling pathways. Specific aims for current project include: 1) to explore molecular profiling in protein expression levels of biotoxin mixture targeted human cells using proteomic techniques. 2) To carry out metabolomic studies in biotoxin mixtures exposed and unexposed animals and human populations, and 3) To continue detoxifying studies with previously identified chemicals for antagonizing combinative acute toxic or cytotoxic effects caused by biotoxin mixtures.

Natural Products and Prevention of Carcinogenesis

Lead By:
Dr. Greg Mayer
Dr. Kamaleshwar Singh

The long-term goal of this research team is to study the potential of antioxidant natural products in prevention strategies to reduce human cancer incidence and mortality in high-risk areas. Focus of current research projects are targeted on breast, kidney, and prostate cancers, including 1) development and validation of molecular biomarkers for human cancer risk studies, and 2) molecular mechanism of natural products-mediated prevention of carcinogenesis.

Molecular Toxicology

Lead By:
Dr. Greg Mayer
Dr. Kamaleshwar Singh
Dr. Ernest Smith

The long-term goal of this research team is to study molecular mechanisms of environmental toxicants linked to the etiology of human acute and chronic diseases and to study molecular pathways for chemical/biological pathogenesis and their interactions. Current research areas include 1) genomic, proteomic, and metabolomic studies on molecular carcinogenesis, 2) stem cell research on human metabolic syndromes, and 3) pathway specific genetic polymorphisms. Tools used include normal and diseases stage cells, whole animal models, human molecular epidemiology studies, and various imaging facilities and analytical instruments.

Developmental and Reproductive Toxicology

Lead By:
Dr. Ernest Smith
Dr. Greg Mayer

Epigenetics and Gene-Environment Interactions in Human Cancer Development

Lead By:
Dr. Kamaleshwar Singh

In spite of tremendous progress made over the last decades in cancer diagnosis and prevention, the cancer remains as one of the leading causes of death in United States, and therefore it is a major public health issue. With technological advancement and genetic research, a number of cancer susceptible genes have been identified. In addition to genetic factors, the increasing number of epidemiological and experimental evidence strongly implicates the role of environmental factors in human cancer development. This is further supported by the facts that approximately 75 – 80% of all cancer in the United States is due to environmental factors, and large proportions (90-95%) of the cancer are sporadic (those cases of cancer that are not due to inheritance of genetic defects in cancer susceptible genes). Therefore, cancer is neither purely genetic nor purely environmental. It is the interaction of gene(s) and environment that ultimately determines the risk of cancer development. Additionally, epigenetic mechanisms have also been shown to play an important role in environmental carcinogenesis. Therefore, in order to understand the mechanistic basis for environment associated cancers, it is crucial to understand how the environmental factors interact with gene(s)/epigenome that results in human malignancies. Though the role of genetic changes of mutations in cancer development is well established, recent reports strongly suggest that epigenetic changes of DNA methylation and histone modifications (methylation and acetylation) play crucial role in the development of human cancers. It is in this context that one of our research objectives is to identify the genetic and epigenetic changes induced by environmental carcinogens and elucidate their role in human malignancy. This study will help understand the mechanistic basis of environmental carcinogenesis and develop suitable strategies for reducing environmental exposure-associated human cancers.

Our research program on epigenetics and gene-environment interaction is designed to provide opportunities for graduate training of theoretical and laboratory-based experimental knowledge on the application of basic biological science (cell biology, molecular biology, and genetics) to address the adverse effects of environmental exposures on human health.

The training through this program will provide our graduates the career opportunities not only in academia, but also in government agencies and private industries.