Key Research Information

Faculty Research Projects

Gail Cherry-Peppers, DDS.

Dr. Cherry-Peppers retired from the US Public Health Service as a Captain, where she was employed by several HHS Agencies, (NIH, HRSA, FDA) as a Dental Clinical Consultant with focus on the oral manifestations of chronic diseases and population sciences. She had leadership and service roles encompassing Women’s Health, Tobacco Use and Oral Health, HIV, Million Hearts and Chronic Diseases in Minority Populations. 

Since joining Howard University College of Dentistry, she serves as the Coordinator of Dental Public Health. Additionally, Dr. Cherry-Peppers serves as the HUCD Coordinator of the National HIV Curriculum, an AIDS Education and Training Center (AETC) National Coordinating Resource Center project with the Howard University HIV Team. The aim of this effort is to orient dental health professionals on how to engage and manage patients living with HIV. Another the goal of the program is to integrate the National HIV Curriculum into the existing dental curricula. The outcome is aimed at strengthening the HBCU HIV clinical workforce, and to reduce HIV disparity in communities of color.

Dr. Cherry-Peppers has interests in systemic diseases and oral health disparities in high risk populations and the broader areas dental public health. Her focus is on the oral manifestations of HIV, Cardiovascular Diseases, Kidney Disease, Diabetes and Metabolic Syndromes.

Esther L.B. Childers, D.D.S.

Dr. Childers is interested in neoplastic and non-neoplastic diseases of the oral and maxillofacial region.   She retired from the US Army Dental Corps as a Colonel and was Chair of the Department of Oral and Maxillofacial Pathology at the Armed Forces Institute of Pathology, where the mission was providing expert diagnostic consultation, education, and research.  Since joining the faculty at HUCD, Dr. Childers has expanded her interest to include cancer education and cancer research training, with a focus on recruiting and preparing minority researchers and educators.

Dr. Childers is focused on clinicopathologic studies to analyze and disseminate information based on her clinical and surgical pathology service.  Specific topics include:  pediatric diseases, odontogenic diseases, and soft tissue diseases.

Xinbin Gu, MD. PhD.

Dr. Xinbin Gu has primarily focused her research in cancer biology, cancer chemoprevention and cancer treatment for head and neck squamous cell carcinoma (HNSCC) and other types of cancers. Her group has reported that vitamin E succinate (alpha-TOS) is able to effectively inhibit HNSCC growth and viability in in vitro and in animal model systems (Clin Cancer Res 2008;15:1840-8). Dr. Gu’s group has discovered a natural compound, Salvianolic Acid B (Sal-B), that suppresses cancer growth through selectively inhibiting cyclooxygenase-2 (COX-2) expression to modulate the cell cycle and apoptosis (Int J Cancer 2009:124:2200-9; Cancer Prevention Res 2010;3:787-96; Oncotarget 2018, PMID: 30555632). Overexpression of COX-2 in the oral mucosa increases the risk of HNSCC. Understanding that selective COX-2 inhibitors can be used as chemo-preventative agents to reduce the risk of cancer. Currently, her group is working on understanding Sal-B’s pharmacokinetics and is developing a delivery system for future clinical trials. 

Dr. Gu’s group has also identified a set of cancer-associated miRNAs and characterized their functions and specific targets using various molecular techniques. Some miRNAs have shown promise in developing novel diagnostic markers and targeted therapies for head and neck cancer (Cancer Prevention Res 2011;4:1073-1083; Oncotarget 2017, PMID: 28212569). In recent years, Dr. Gu’s group has been working on a NIDCR funded project to develop the next generation of immunotherapy for cancer. Some of their ongoing developments include a humanized EGFR and EGFRvlll-bispecific immunotoxin for head and neck cancer therapy. 

In addition, Dr. Gu’s group has been working on a NDAF funded project to identify noninvasive salivary biomarkers for early diagnosis of diabetes and gum disease. They have found that the levels of salivary mucin proteins, such as mucin 7 and 5, are correlated with A1C levels. Their next step involves comparing and verifying the results within various populations.

Brian Laurence, DDS, PhD.

Dr. Brian Laurence is both a dentist and epidemiologist. He serves as the Director of Student and Community-Based Research Initiatives at the Howard University College of Dentistry. Dr. Laurence has published studies on the clinical outcomes associated with sickle cell disease and dental health. He has published studies on the associations among oral health, systemic health, and depression. He has also studied systemic health using hospital admission as a marker for worsening overall health. In addition, he has published on inter-professional approaches to evidence-based dental education.

Dr. Laurence is currently completing data collection on the Howard-Meharry Adolescent Caries Study (H-MACS). The study investigates the association between sugar sweetened beverage (SSB) consumption and dental caries in African American adolescents in the Washington, DC and Nashville, TN regions. Secondary aims of the project include measuring the prevalence of periodontal disease and other dental outcomes among African-American adolescents. This project has utilized a unique approach to partnering community-based research with the provision of preventive oral health. His research team has already submitted the first manuscript from this collaborative project. 

Dr. Laurence is also working with the research faculty from Medstar Health. He is currently completing an analysis of secondary data that will provide dental outcome data for patients visiting hospitals in Maryland. In addition, he has recently completed another funded project in which he examined the implementation of random inspections and a checklist in reducing plaque scores among elderly patients in long-term care facilities. 

Indra Mustapha, DDS, MS, PhD.

Dr. Mustapha is a board-certified Periodontist who, in private practice, has witnessed how periodontal inflammation has effects beyond the oral cavity and has a relationship with systemic health. Her PhD training in Clinical Investigation at Johns Hopkins University has assisted her to design clinical studies, analyze data, and interpret results.  Her work has included studying the systemic inflammation associated with periodontal disease, cardiovascular disease, diabetes, human-papilloma virus and oropharyngeal cancer. 

Dr. Mustapha has developed clinical studies in the College of Dentistry at Howard University to benefit the Washington DC population. Not only is Dr. Mustapha a role model for students, but she is known for helping others in the community and being a leader in oral and systemic inflammation with her clinical research. Her community-based, clinical work has been funded by NIH.

Dr. Mustapha’s publications thus far include: “Markers of systemic bacterial exposure in periodontal disease and cardiovascular disease risk-A systematic review and meta-analysis”, and a book chapter in a Center for Disease publication (“Chapter. 11: The Associations of Diabetes with Digestive, Oral and Liver Disease and Autonomic Neuropathy. Diabetes Public Health: From Data to Policy’).

Xiaowu Pang, PhD.

Dr. Pang earned his B.Sc. in Biochemistry from Wuhan University and his Ph.D in Biochemistry from the Virginia Commonwealth University College of Medicine. His early research focused on studying the mechanism behind flavivirus replication and RNA replicon development. Flavivirus RNA replicons are derived from the positive-strand viral RNA genome with at least one gene encoding an essential structural protein that has been deleted. RNA replicons can be regarded as disabled viruses unable to produce infectious progeny. Despite such gene deletions, the viral RNA is replicated and transcribed by the viral RNA polymerase. Any genetic information encoded by the replicon will be amplified many times, resulting in high levels of antigen expression. This property distinguishes RNA replicons from plasmid DNA-based vaccines, which rely on the initial levels of genetic information successfully delivered to the nucleus. His early publications have found that flavivirus replicons have great potential as vaccine vectors. The replicons are naturally non-cytopathic, induce strong cellular immune responses, and can be incorporated into virus-like particles (VLP) by packaging cell lines. 

Dr. Pang, along with his colleagues, has also completed studies on antigen-specific immunotherapy for cancer. Since constant expression of Human papillomavirus (HPV) viral proteins E6 and E7 is required for transformation and maintenance of the malignant phenotype, E6 and E7 antigens may represent ideal targets for therapeutic vaccines against HPV-associated cancer. He has found that the efficacy of a therapeutic vaccine can be further enhanced by a modulation of the cancer microenvironment. 

Dr. Pang’s research is currently supported by NIH STTR grant.

Tongxin Wang, PhD.

Dr. Tongxin Wang is a full-time professor, who is jointly appointed with the College of Dentistry and Center for Nanomaterials in College of Engineering. Dr. Wang obtained his Ph.D. from the Institute of Chemistry at the Chinese Academy of Sciences (ICCAS) in 2003. Before he joined Howard University in 2007, Dr. Wang worked at the Max Planck Institute of Colloids and Interfaces in Germany in 2003 and at the University of Pennsylvania in 2005 as a postdoctoral fellow. The unique feature of Wang’s lab is to combine polymers, nanomaterials, biomimetic / bio-inspired materials, and composites in order to develop novel biomaterials for bone and tooth application. Dr. Wang’s research has been supported by NIH R01, R56, RCMI/RTRN, the Department of Defense, and the Colgate Palmolive Company. His current research projects include: 

  • High performance bioresorbable nanocomposites for bone repair; 
  • Biomimetic mineralization for tooth repair; 
  • Tooth remineralization and tooth erosion prevention; 
  • Biomimetic dental composites with prolonged lifespan; 

Dr. Tongxin Wang has published more than 40 publications in peer reviewed journals including: J. Am. Chem. Soc., Angew. Chem., Langmuir, Adv. Mater., J. Dent. Res., etc. Several of them have been featured on the front covers or inside covers of the journals and have been reported by many media platforms. Dr. Wang has established wide collaborations with both domestic and internationally renowned institutions such as the American Dental Association, the Paffenbarger Research Center at the National Institute of Standards and Technology (NIST), the Chinese Academy of Sciences (CAS) School of Stomatology, Peking University, and the Colgate-Palmolive Company. Dr. Tongxin Wang has received the First Prize Award (2012) from the Junior Faculty on Health Sciences Research Day and the Inspirational Interdisciplinary Project Award for Faculty (2014) at Howard University. Dr. Wang also currently serves as a grant reviewer for NIH/SBIR/STTR, R21, R15, and R01 on bone and dental materials.

Guiqin Xie, MD, PhD.

Dr. Guiqin Xie joined Dr. Xinbin Gu’s research team in 2019 at Howard University College of Dentistry. She has since been actively developing new approaches for the treatment of head and neck cancer, glioblastoma multiforme, hepatocellular carcinoma and other types of cancers with focuses on: (1) development of T cell-mediated targeted gene delivery of immunotoxin in head and neck squamous cell carcinoma (HNSCC). Recombinant immunotoxin (RIT) has been shown to be extremely effective for the treatment of some hematopoietic malignancies. However, RIT is a highly immunogenic and very toxic protein, preventing its use as an effective treatment for solid tumors, including HNSCC. We will develop a novel approach to overcome the critical limitations of the current RIT application for treating HNSCC; (2) investigation of oncogenic transcriptional vulnerability to treat head and neck cancer. Multiple oncogenic events confer tumor cells transcriptional dependence for cell cycle progression which may eventually serve as biomarker for therapeutic targets; (3) development of combinatorial treatment of MEK inhibitor and transcription inhibition in head and neck cancer. Combination of a MEK inhibitor and a transcription inhibitor has shown potential efficacy in tumor cells in vitro. As Principal Investigator, Dr. Xie recently received a NIDCR/NIH R03 grant focusing on cancer immunotherapy.