Production of various marker substances in human ovarian cancer cell lines of epithelial origin

Oncolytic viral therapy for cervical and ovarian cancer cells by Sindbis virus AR339 strain

PURPOSE

Recently, the application of replication-competent viruses has been studied as anticancer agents. Sindbis virus (SIN) is an RNA virus that belongs to the Alphavirus genus in the Togaviridae virus family. The AR339 strain of SIN has not been reported to induce any serious disease to humans.

EXPERIMENTAL DESIGN

In this study, we evaluated the feasibility of the replication-competent SIN AR339 strain as an agent for cervical and ovarian cancer therapy.

RESULTS

SIN infection was able to induce cytopathic effects and apoptosis in two cervical cancer cells (HeLaS3 and C33A) and three ovarian cancer cells (HOC-1, HAC-2, and OMC-3) but not in normal human keratinocytes in vitro. The analysis of cell viability, virus protein synthesis, and viral growth showed the cancer-specific cytotoxicity and virus growth of SIN. In nude mice, i.t. and i.v. inoculation of SIN resulted in significant regression of established cervical tumors implanted at their backs. Histologic studies revealed that systemic treatment with the single injection of SIN induces necrosis within tumors at a remote site. In the metastasis model of ovarian cancer, suppression of ascites formation was observed in nude mice with i.p. SIN treatment. By using an in vivo green fluorescent protein imaging system, we also showed that systemic treatment with SIN targeted tumors specifically.

CONCLUSIONS

Our study suggested that SIN AR339 strain has a possibility as a novel agent for human cervical and ovarian cancer therapy.

Establishment and characterization of a new HPV-negative squamous cell carcinoma cell line (Yumoto) from the human uterine cervix

A new cell line, Yumoto, derived from a squamous cell carcinoma of the uterine cervix, was established from serially transplanted tumor tissues in nude mice. Monolayer cultured cells were polygonal and formed pavement-like sheet. They showed a piling-up tendency and were devoid of contact inhibition. Electron micrographs demonstrated the presence of microvilli on the cell surface, abundant tonofilaments in the cytoplasm, and the connection with desmosomes. These electron micrographical characteristics of Yumoto cells were consistent with those of squamous cell origin. Yumoto cells were highly tumorigenic in BALB/c nude mice and produced a well-differentiated squamous cell carcinoma of keratinizing type which closely resembled to the original tumor tissues in nude mice. The presence of HPV DNA was examined using polymerase chain reaction and Southern blot analysis, but no known types of HPV DNA could be detected. Exons 2 through 11 of the p53 gene were analyzed by direct DNA sequencing, revealing a homozygous mutation at codon 281 in exon 8, GAC to CAC (Asp-->His). Furthermore, physical p53-gene deletion was demonstrated by dual-color fluorescence in situ hybridization. This cell line is useful for studying the carcinogenesis of cervical carcinoma and for investigating the biological characteristics of a HPV-negative and mutated p53 squamous cell carcinoma of the uterine cervix.

Interleukin-6 (IL-6) production in carcinoma of the cervix

Interleukin-6 (IL-6) is a pleiotropic cytokine that is not only a mediator in major immunologic reactions but also a growth factor of keratinocytes. We studied the IL-6 secretion in vitro of 15 human cell lines derived from both squamous cell carcinoma (SCC) and adenocarcinoma of the uterine cervix. Four of the eight well differentiated SCC secreted a large amount (> 1500 pg/48 h/10(6) cells) of IL-6 in nude mice. In contrast, poorly differentiated SCC cell lines and all of the 7 adenocarcinoma cell lines secreted a small amount (< 500 pg/48 h/10(6) cells of IL-6). The expression of IL-6 mRNA of the cell lines correlated well with their IL-6 secretion potential. However, the expression of IL-6 receptor did not correlate with the IL-6 secretory potential. We also studied the IL-6 secretion of freshly isolated normal squamous epithelium and of dysplastic epithelium. In culture, two normal squamous epithelia secreted a large amount (> 2000 pg/48 h/10(6) cells), whereas 8 dysplasia epithelia secreted an extremely small amount (< 10 pg/48 h/10(6) cells). About one-third of patients with SCC had a raised serum IL-6 value. IL-6 production may help to differentiate between SCC and adenocarcinoma of the uterine cervix. IL-6 regulation seems to change in the course of SCC carcinogenesis.

Expression of a human multidrug resistance gene in human ovarian carcinoma cell lines

To investigate the possible role of the multidrug resistance phenotype to chemoresistance in human ovarian carcinoma, we have analyzed human multidrug resistance gene (mdr 1) expression in 8 human ovarian adenocarcinoma cell lines. An increase in P-glycoprotein level specific to multidrug-resistant tumor cells was not apparently associated with the increase in resistance to vincristine (VCR) or doxorubicin (Adriamycin). Mdr 1 transcripts (4.5 kilobases) were observed in the RNA preparation obtained from only one cell line (SHIN-3) that showed the highest resistance to both drugs in vitro and in vivo. No cell lines showed mdr 1 DNA amplification. These results suggest that the insensitivity of human ovarian carcinoma to chemotherapy could be partly explained by the expression of mdr 1.