Strategies to accomplish targeted expression of transgenes in ovarian cancer for molecular therapeutic applications.

PURPOSE: The purpose of the study was to determine the capability of the midkine (MK) and cycooxygenase-2 (cox-2) gene promoter regions to function as tumor-specific promoters for use in targeted gene therapy of ovarian cancer. EXPERIMENTAL DESIGN: Established and primary ovarian cancer and mesothelial cells were transduced by adenoviral vectors containing a reporter or thymidine kinase gene expressed under the control of the MK, cox-2, or cytomegalovirus (CMV) promoters. SCID or C57BL/6 mice were injected i.p. with these same vectors. In vitro reporter gene expression and cellular cytotoxicity was determined using luciferase and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, respectively. Acute toxicity in vivo was assessed by histological evaluation of harvested tissues. RESULTS: Consistent activation of the MK and cox-2 promoters was noted in all of the ovarian cancer cell lines in addition to primary ovarian cancer cells. In contrast, reduced reporter activity was reported in mesothelial cells transduced with adenoviruses containing the test promoters, which was especially apparent for the cox-2 promoter. Additionally, the cox-2 promoter exhibited significantly lower reporter gene levels in liver and peritoneum than the control promoter in in vivo experiments. Tumor-cell killing induced by Adcox-2 MTK was comparable to that observed with AdCMVTK. However, a clear differential toxicity pattern was observed in favor of animals treated with Adcox-2 MTK when compared with controls. CONCLUSIONS: These data clearly demonstrate that the transcriptional control afforded by the cox-2 promoter is tumor-specific and is able to mitigate associated toxicity in normal tissue while maintaining therapeutic efficacy in the context of an ovarian cancer molecular chemotherapeutic approach.

An immunomagnetic-based method for the purification of ovarian cancer cells from patient-derived ascites.

OBJECTIVE: Primary ovarian cancer cells obtained from fresh tumor have many advantages over established cell lines. Therefore, a procedure for the specific and efficient purification of such neoplastic cells is critical. We report an effective immunomagnetic method for the isolation of tumor cells from the ascitic fluid of patients diagnosed with ovarian adenocarcinoma. METHODS: This procedure incorporates the use of monoclonal antibody (mAb) CC49, which recognizes the tumor-associated glycoprotein 72 (TAG-72). TAG-72 is highly expressed on ovarian tumor cell surfaces with little or no reactivity with normal tissues. Also used in this protocol are immunomagnetic beads, which bind to the CC49 mAb via a secondary antibody. When ovarian cancer cells adhere to the magnetic beads, a magnetic field is used to separate the tumor cells from all other cellular components. RESULTS: Using ascitic fluid from five patients, we found that preparations before purification contained between 38 and 52% neoplastic cells. Using our method, we produced preparations that were between 63 and 96% pure for cancer cells, thus obtaining an average increase in tumor cell enrichment of 86%. CONCLUSION: We, therefore, believe this method is preferable for producing high yields of pure ovarian neoplastic cells. We are now employing this technique in our laboratory to provide a stringent and pure template for our studies on gene transfer to primary ovarian cancer cells.

Current strategies in gene therapy for ovarian cancer.

The application of gene therapy strategies for ovarian cancer has employed various viral and nonviral vectors. Thus far, adenovirus has been the most promising vehicle for gene replacement but the use of non DNA-based viruses is also being explored. Recent novel advances in gene therapy approaches include refinement of vector targeting and the use of site-specific promoters and conditionally replicative adenoviral vectors. Although several clinical trials have documented the relative safety of gene therapy in ovarian cancer patients, few significant clinical responses have been effected. However, advances in the field are occurring rapidly and this strategy does appear promising for the treatment of ovarian cancer.

Lysophosphatidic acid induces urokinase secretion by ovarian cancer cells.

Lysophosphatidic acid (LPA) is present at high concentrations in ascites from ovarian cancer patients and has potent mitogenic properties in vitro. Urokinase plasminogen activator (uPA), a critical component of the metastatic cascade, is also found at high concentrations in ovarian ascites and ovarian cancers, and the levels of uPA correlate inversely with prognosis. Because LPA stimulates the invasion of both hepatoma and lung cell lines, we investigated whether LPA could induce uPA secretion by ovarian epithelial cells and whether this process was associated with malignant transformation of ovarian epithelial cells. As indicated by zymography and Western blotting, physiologically relevant concentrations of LPA equivalent to those present in ovarian cancer ascites stimulated uPA secretion in the ovarian cancer cell lines OVCAR-3, SKOV-3, OVCA 429, OVCA 432, and OVCA 433, but not from established normal ovarian epithelial (NOE) cells as indicated by normal epithelial cell lines NOE 033 and NOE 035 or from SV40 large T antigen-immortalized normal epithelial cell lines IOSE 29 and IOSE 80. 18:1 LPA, but not 18:0 LPA, 16:0 LPA, or lysophosphatidylcholine, induced uPA secretion, concordant with previous studies of LPA receptor selectivity. Expression of the edg-2 LPA receptor was not consistently different between normal epithelial cell lines and ovarian cancer cell lines. In contrast, expression of the edg-4 LPA receptor was markedly increased in ovarian cancer cell lines as compared with NOE cell lines, raising the possibility that the edg-4 LPA receptor contributes to the ability of ovarian cancer cells but not NOE cells to produce uPA in response to LPA. LPA induced a consistent increase in uPA promoter activity and mRNA levels, suggesting that increased uPA production is, at least in part, transcriptional. Malignant transformation may alter LPA-induced cell activation by altering the pattern of LPA receptors present and may possibly lead to more aggressive behavior by up-regulating LPA-mediated uPA secretion and stimulating extracellular stromal breakdown and invasion.

Unicornuate uterus with a rudimentary horn and ovarian dysgerminoma. A case report.

BACKGROUND: Several documented cases of endometrial and cervical carcinoma arising in unicornuate uteri have been described; however, ovarian malignancy occurring in conjunction with this müllerian anomaly has not been reported. CASE: An 18-year-old woman had a unicornuate uterus, noncommunicating rudimentary horn and homogeneous, solid, right ovarian mass found to be a dysgerminoma at surgery. CONCLUSION: Müllerian anomalies are unlikely to predispose women to ovarian malignancies. However, it is essential to keep in mind that women with such anomalies, though presenting at a young age, could still have cervical, uterine or even ovarian malignancies.

Parvovirus B19 infection in a twin pregnancy.

BACKGROUND: Parvovirus infection has been associated with the development of nonimmune hydrops fetalis in pregnancy. This report describes a twin pregnancy in which one fetus was affected by parvovirus B19 and the other was not. CASE: A 35-year-old woman was found to have a twin gestation at genetic amniocentesis. Subsequent ultrasound at 18 weeks showed that twin B had evidence of hydrops fetalis. Serum from the mother tested positive for parvovirus B19 immunoglobulin (Ig) G and IgM. Cultured amniotic fluid from twin B was subsequently found to be positive for parvovirus B19. At 20 weeks' gestation, the hydropic fetus died. The unaffected fetus grew normally. At 40 weeks, the unaffected fetus was delivered vaginally with no difficulties. Cord blood from the unaffected fetus was negative for parvovirus B19 IgM. CONCLUSION: This case demonstrates differential infection of parvovirus B19 in a diamniotic, dichorionic twin pregnancy. One twin developed signs of hydrops fetalis consistent with parvovirus B19. The diagnosis was confirmed immunologically and by amniotic fluid culture. The second twin had no evidence of parvovirus B19 and no immunologic suggestion of infection at birth. This is the only known report of such differential transmission of parvovirus B19 in a twin pregnancy.