Alloantigen gene therapy for head and neck cancer: evaluation of animal models

The current state of head and neck cancer gene therapy

The incidence of head and neck cancer continues to increase worldwide, with tobacco exposure and human papillomavirus type 16 infections being the major etiological factors. Current therapeutic options are ineffective in approximately half of the individuals afflicted with this malignancy. Developments in the identification of molecules that sustain head and neck squamous cell carcinoma (HNSCC) growth and survival have made molecular targeting by gene therapy approaches a feasible therapeutic strategy. Although gene therapy was originally designed to correct single gene defects, it has now evolved to encompass all forms of therapeutic interventions involving engineered cells and nucleic acids that modify the overall pattern of gene expression within target tissues. Several preclinical studies and clinical trials have tested the efficacy of targeting specific molecules in patients with HNSCC, using genetic therapy approaches. This review discusses promising preclinical and clinical approaches and new directions for HNSCC gene therapy.

Animal models in oral cancer research

Biologically and clinically relevant animal models are essential in investigation of the progression of diseases and the elaboration of diagnostic or therapeutic protocols. The several rodent models used for in vivo evaluation for oral cancer employ chemical, transplantation and genetic (knockout and transgenic) induction methods. These models are described together with their advantages and disadvantages. Their optimization and application in future research may improve the early detection and treatment of oral cancer.

Animal models for the study of squamous cell carcinoma of the upper aerodigestive tract: a historical perspective with review of their utility and limitations. Part A. Chemically-induced de novo cancer, syngeneic animal models of HNSCC, animal models of transplanted xenogeneic human tumors

Understanding the complex histological, genetic and molecular changes that lead to malignant transformation of squamous epithelia of the head and neck will likely guide the development of methods for improved diagnosis, monitoring and treatment of head and neck squamous cell carcinoma (HNSCC). The development and use of animal models that closely mimic the histopathology and molecular pathogenesis of HNSCC in humans would greatly expand the research possibilities and provide a means of testing potential therapeutic agents. However, many available animal models of HNSCC fall short of this objective. In order for investigators to select the appropriate model to answer scientific questions, it is important to understand the benefits and limitations of available animal models for the study of HNSCC. The purpose of this work is to give an overview of the most pertinent animal models of HNSCC, and to discuss future directions of research in this field.

Major histocompatibility gene therapy: the importance of haplotype and beta 2-microglobulin

OBJECTIVES/HYPOTHESIS

Alloantigen gene therapy with the genes for the Class I major histocompatibility complex (MHC) HLA-B7 and beta 2-microglobulin in HLA-B7-negative patients has potential efficacy in the treatment of head and neck cancer, although the mechanism of response is unclear. Whether tumor regression is due to a response to HLA-B7 in HLA-B7-negative patients (i.e., due to "foreign" antigen) or simply to MHC overexpression is unknown. Therefore, a mouse model was used to compare tumor growth following syngeneic MHC transfection to alloantigenic MHC transfection. The importance of the beta 2-microglobulin gene was also evaluated.

STUDY DESIGN

Prospective animal study.

METHODS

The head and neck cancer cell line SCC-VII that grows in immunocompetent C3H mice, which are MHC haplotype H2-K, was used. Stable transfections were made with H2-K, H2-K, and beta 2-microglobulin in the SCC-VII cells. To test the importance of MHC "foreignness," mice were injected with SCC-VII cells, SCC-VII plus H2-K plus beta 2-microglobulin transfected cells, and SCC-VII plus H2-K plus beta 2-microglobulin transfected cells. To evaluate beta 2-microglobulin, mice were injected with SCC-VII cells, SCC-VII plus H2-K plus beta 2-microglobulin transfected cells, SCC-VII plusH2-K transfected cells, and SCC-VII plus beta 2-microglobulin transfected cells. Tumor growth in all groups was compared statistically.

RESULTS

Major histocompatibility complex foreignness was a part of the antitumor response. Foreign MHC routinely abrogated tumor growth, whereas syngeneic MHC only slowed tumor growth. beta 2-microglobulin aided the MHC tumor inhibition but did not inhibit tumor without the MHC.

CONCLUSION

The antitumor response was greater when the MHC gene used was foreign. beta 2-microglobulin increased the efficacy of MHC gene therapy. Both of these findings are important when designing clinical trials of immunologically based gene therapies for head and neck cancer.

Progress in Head and Neck Cancer Immunotherapy: Can Tolerance and Immune Suppression Be Reversed?

The incidence of squamous cell carcinoma of the head and neck (SCCHN) is greater than 40,000 cases per year in the United States, and approximately 500,000 cases annually worldwide. Despite significant advances in detection, ablation, and reconstruction, survival has not improved appreciably over the past few decades. Therefore, novel approaches are necessary to provide head and neck oncologists with a more effective armamentarium against this challenging disease. Cancer immunotherapy describes various approaches to expand and activate the immune system to control tumor growth in vivo. So far, immunotherapy appears to have had applicability in conjunction with other therapeutic interventions that treat residual tumor cells after therapy or to reduce the occurrence of second primary tumors. In particular, diseases such as SCCHN are attractive candidates for novel therapeutic approaches, since the standard treatments have not yet successfully controlled this disease with sufficiently high success rates. This article reviews adjuvant immunotherapeutic strategies currently in trials or under development for SCCHN patients, including vaccination or cytokine immunostimulation.