No abstract

The mechanisms of drug resistance in cancer are poorly understood. Serial analysis of gene expression (SAGE) profiling of cisplatin-resistant and sensitive cells revealed many differentially expressed genes. Remarkably, many ECM genes were elevated in cisplatin-resistant cells. COL6A3 was one of the most highly upregulated genes, and cultivation of cisplatin-sensitive cells in the presence of collagen VI protein promoted resistance in vitro. Staining of ovarian tumors with collagen VI antibodies confirmed collagen VI expression in vivo and suggested reorganization of the extracellular matrix in the vicinity of the tumor. Furthermore, the presence of collagen VI correlated with tumor grade, an ovarian cancer prognostic factor. These results suggest that tumor cells may directly remodel their microenvironment to increase their survival in the presence of chemotherapeutic drugs.

Compared to normal human tissues, many common human cancers, including carcinoma of the colon, prostate, ovary, breast, and endometrium, express high levels of fatty acid synthase (FAS, EC ), the primary enzyme responsible for the synthesis of fatty acids. This differential expression of FAS between normal tissues and cancer has led to the notion that FAS is a target for anticancer drug development. Recent studies with C75, an inhibitor of fatty acid synthesis, have shown significant antitumor activity with concomitant inhibition of fatty acid synthesis in tumor tissue and normal liver. Importantly, histopathological analysis of normal tissues after C75 treatment showed no adverse effects on proliferating cellular compartments, such as bone marrow, gastrointestinal tract, skin, or lymphoid tissues. In this study, we describe the de novo synthesis of C75 based on the known mechanism of action of cerulenin and the theoretical reaction intermediates of the beta-ketoacyl synthase moiety of FAS. In addition, we demonstrate that C75 is a synthetic, chemically stable inhibitor of FAS. C75 inhibits purified mammalian FAS with characteristics of a slow-binding inhibitor and also inhibits fatty acid synthesis in human cancer cells. Treatment of human breast cancer cells with [5-(3)H]C75 demonstrates that C75 reacts preferentially with FAS in whole cells. Therefore, we have shown that the primary mechanism of the antitumor activity of C75 is likely mediated through its interaction with, and inhibition of, FAS. This development will enable the in vivo study of FAS inhibition in human cancer and other metabolic diseases.

Purpose: Persistent infection with oncogenic human papillomaviruses (HPV) plays a central etiologic role in the development of squamous carcinomas of the cervix and their precursor lesions, cervical intraepithelial neoplasias (CIN). We carried out a prospective observational cohort study evaluating known, quantifiable prognostic variables of clinical behavior in women with high-grade cervical lesions. Experimental Design: Our study cohort included healthy women with high-grade cervical lesions (CIN2/3) with residual visible lesions after colposcopically directed biopsy. We prospectively followed 100 women over 15 weeks before standard resection. HPV typing was done using PCR and a reverse line blot detection method. Results: The rate of spontaneous histologic regression, defined as (CIN1 or less at resection) was 28%. The overall rate of HPV infection was 100%. HPV16 was identified in 68% of the lesions. Women with HPV16 only were significantly less likely to regress, compared with women with HPV types other than HPV16 (odds ratio, 0.342; 95% confidence interval, 0.117-0.997; P = 0.049). In the cohort with HPV16 only, patients who had an HLA*A201 allele had similar outcomes to those who did not carryA201. However, among patients with HPV types other than HPV16, the HLA*A201 allele interaction was significant; patients with HLA*A201 were the least likely to resolve. Conclusions: CIN2/3 lesions associated with HPV16 alone are significantly less likely to resolve spontaneously than those caused by other types. Interactions among HPV type, HLA type, and regression rate support a role for HLA-restricted HPV-specific immune responses in determining disease outcome.Persistent infection with a high risk, or oncogenic type of human papillomavirus (HPV) is necessary but not sufficient for the development of most squamous carcinomas of the cervix and their precursor lesions, cervical intraepithelial neoplasia (CIN; ref. 1). CIN1, CIN2, and CIN3 lesions represent a spectrum of disease. Low-grade, or CIN1 lesions, represent a chronic HPV infection, in which HPV DNA is episomal and intact virion production and shedding occur. In women who are immunocompetent, many low-grade, or CIN1 lesions, will nonetheless eventually regress without intervention (1, 2). Reported rates of regression range up to 58% over 24 months (3). A very small percentage (f2%) will progress to high-grade lesions.In contrast, most high-grade, or CIN2/3 lesions are thought to be much more likely to persist than to regress. However, reported rates of spontaneous regression vary from 6% to 50%, depending on diagnostic criteria, and length of follow-up (4). The risk for progression to invasive cancer at 24 months in women with high-grade lesions is f1% to 2%.The mechanisms by which HPV-associated intraepithelial lesions resolve are not well understood. As a prelude to interventional clinical trials in women with biopsy-proven CIN2/3, we carried out a prospective observational cohort study evaluating known, quantifiable prognostic variables in immune ...