Paclitaxel (Taxol) is currently used as the front-line chemotherapeutic agent for several cancers including ovarian carcinoma; however, the drug frequently induces drug resistance through multiple mechanisms. The new strategy of using natural compounds in combination therapies is highly attractive because those compounds may enhance the efficacy of chemotherapy. In this study, we found that tectorigenin, an isoflavonoid isolated from flower of Pueraria thunbergiana, enhanced the growth-inhibitory effect of paclitaxel in paclitaxel-resistant ovarian cancer cells (MPSC1(TR), A2780(TR) and SKOV3(TR)) as well as their naive counterparts. The combination of tectorigenin with paclitaxel resulted in a synergistic apoptosis compared with either agent alone through activation of caspases-3, -8 and -9. Treatment with tectorigenin inhibited the nuclear translocation of NFκB and the expression of NFκB-dependent genes such as FLIP, XIAP, Bcl-2, Bcl-xL and COX-2, which are known to be associated with chemoresistance. In addition, the tectorigenin-paclitaxel combination inhibited the phosphorylation of IκB and IKK and the activation of Akt in paclitaxel-resistant cancer cells. Moreover, tectorigenin-paclitaxel-induced cell growth inhibition was enhanced by pretreatment with the Akt inhibitor LY294002 or overexpression of the dominant negative Akt (Akt-DN), but reduced by overexpression of constitutively activated Akt (Akt-Myr). Furthermore, we found that Akt-Myr, at least in part, reversed tectorigenin-paclitaxel-induced nuclear translocation of NFκB and the phosphorylation of IκB and IKK. These data suggest that tectorigenin could sensitize paclitaxel-resistant human ovarian cancer cells through inactivation of the Akt/IKK/IκB/NFκB signaling pathway, and promise a new intervention to chemosensitize paclitaxel-induced cytotoxicity in ovarian cancer.

Purpose: The goal of this study was to investigate the therapeutic potentials of combining chemotherapy with human papillomavirus (HPV) E7 subunit vaccines in an animal tumor model and to determine the underlying therapeutic mechanisms. Experimental Design: Animals bearing HPV E6/E7^expressing tumors were treated intratumorally with a selected cytotoxic drug, cisplatin, twice at 1-week interval and s.c. with E7 subunit vaccines thrice at 1-week interval. Tumor chemoimmunoresponse was measured by tumor size. Ag-specific CTL activities and tumor histology were checked in mice under treatments. Apoptosis, in vivo T-cell subset depletion, adoptive CTL transfer, and tumor regression were used to determine the mechanisms for antitumor therapeutic effects. Results: Combined therapy using cisplatin plus E7 subunit vaccines improved cure and recurrence rates of tumors and long-term antitumor immunity dramatically more than single therapy alone. In particular, both components of E7 subunit vaccines were required for induction of Ag-specific CTL as well as therapeutic synergy when combined with cisplatin. This therapeutic synergy was abrogated by depletion of CD8 + Tcells in vivo and was concomitant with histologic changes (such as heavy infiltration of lymphocytes and reduced tumor cell density). Finally, the increased sensitivity of cisplatin-treated tumors to CTL-mediated killing was found to be responsible for therapeutic synergy. Conclusions: E7 subunit vaccines plus cisplatin mediate antitumor therapeutic synergy through the increased sensitivity of cisplatin-treated tumors to CTL-mediated killing. Moreover, E7-based therapeutic vaccines have the potential to improve chemotherapy in patients with cervical cancer.Cervical cancer of the uterus is caused mainly by infection with human papillomavirus (HPV; ref. 1). Presently, HPV virus-like particle-based prophylactic vaccination against HPV infection is expected to reduce cervical cancer incidence. In women already infected with HPV, however, therapeutic vaccines are one promising option for control of cervical cancer incidence. To date, HPV E6 and E7 proteins have been a major target for immune-based therapeutic strategies against HPV-derived cervical cancers as they are expressed constantly in cervical cancer cells (2, 3). In particular, a variety of E6-or E7-targeted vaccine types have been tested preclinically and in humans. These include peptide vaccines (4 -6), DNA vaccines (7 -10), recombinant proteins (11 -13), dendritic cell -based vaccines (14 -17), and viral/bacterial delivery of vaccines (18 -20). These studies have shown the importance of T-cell responses, particularly CTL in clearing cervical lesions in humans or tumors in animals. In our recent findings, tumor burden is inversely related to E7 subunit vaccine-induced antitumor therapeutic efficacy (21). For instance, E7 subunit vaccines were able to cure tumors of a smaller size (2 mm in diameter) but not larger tumors (6-8 mm in diameter). This prompted us to evaluate whether E7 subunit vaccines...

ObjectiveThe purpose of the current study was to evaluate survival outcome according to the expression status of CD73 in patients with epithelial ovarian cancer.MethodsA total of 167 patients with epithelial ovarian cancer were enrolled in the current study. For each patient, a retrospective review of medical records was conducted. Immunohistochemical staining for CD73, CD8, FoxP3, and CD68 was performed using tissue microarray made with paraffin embedded tissue block.ResultsAmong the enrolled patients, 29.9% of patients (n=50) showed negative expression for CD73, whereas 70.1% of patients (n=117) showed positive expression for CD73. The CD73 positive group showed better prognosis compared to the CD73 negative group (5-year overall survival of CD73 positive group, 73.0%; that of CD73 negative group, 50.1%; p=0.023). CD73 was more frequently expressed in mucinous adenocarcinoma and clear cell carcinoma compared to serous or endometrioid adenocarcinoma. In addition, CD73 overexpressions were more frequently detected in patients with known good prognostic factors, i.e., low stage, well/moderate differentiation, negative peritoneal cytology, no lymphovascular involvement, and no macroscopic residual tumor after debulking surgery. There was significantly more infiltration of regulatory T cells in the CD73 negative group compared to the CD73 positive group.ConclusionGood prognosis in patients with overexpression of CD73 may be due to that overexpression of CD73 was more frequently observed in epithelial ovarian cancer patients with known good prognostic factors. Therefore, this result means that favorable differentiation and stage have more influence on survival outcome than adverse effect of CD73 per se.

Despite evidence that leptin may play a role in the pathogenesis of endometriosis, the specific function of leptin in the migration and invasion of endometriotic cells is not well characterized. In this study, we investigated the effect of leptin on the migration, invasion and matrix metalloproteinase (MMP) expression levels of human endometriotic cells. We found that leptin stimulated the migration and invasion of endometriotic cells (11Z, 12Z and 22B) in a dose-dependent manner. Leptin receptor (ObR) siRNA significantly inhibited the migration and invasion induced by leptin in 11Z and 12Z cells. Leptin-induced migration and invasion were significantly attenuated by pretreatment with SB-3CT, a specific gelatinase (MMP-2 and MMP-9) inhibitor. In addition, leptin-induced increases in the mRNA and protein expression and enzyme activity of MMP-2 in 11Z and 12Z cells. Selectively inhibiting MMP-2 using siRNA and an inhibitor (GM6003), impaired the ability of leptin to stimulate the migration and invasion of endometriotic cells, suggesting that MMP-2 plays an essential role in leptin-induced migration and invasion. Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (JAK2/STAT3) inhibitor (AG490) significantly inhibited the migration, invasion and MMP-2 expression induced by leptin in endometriotic cells. Furthermore, the Extracellular signal-Regulated Kinase inhibitor PD98059 neutralized the migration and invasion promoting effects of leptin. Taken together, these results suggest that leptin may contribute to the migration and invasion abilities of endometriotic cells via the up-regulation of MMP-2 through an ObR-dependent JAK2/STAT3 signaling pathway.

Intratumoral electroporation (IT-EP) with IL-12 cDNA (IT-EP/IL12) can lead to the eradication of established B16 melanoma tumors in mice. Here, we explore the immunological mechanism of the antitumor effects generated by this therapy. The results show that IT-EP/IL12 applied only once resulted in eradication in 70% animals with large established B16 tumors. Tumor eradication required the participation of CD8+ T cells, but not CD4+ T cells and NK cells. IT-EP/IL12 induced antigen-specific CD8+ T cell responses against the immunodominant Trp2(180-188) epitope and generated a systemic response, resulting in significant therapeutic effects against distal, untreated tumors. The therapeutic effect of IT-EP/IL12 was absent in perforin-deficient mice, indicating that tumor elimination occurred through conventional perforin/granzyme lysis by CTLs. Moreover, this therapy induced some degree of immunological memory that protected approximately one-third of the cured mice against a subsequent tumor challenge. Moreover, antitumor efficacy and long-term protection against B16 were significantly improved by concurrent Trp2 peptide immunization through more induction of Ag-specific CTL responses and more attraction of IFN-γ-expressing CD8+ T cells into tumor sites. The antitumor effect of IT-EP/IL12 required the participation of IFN-γ, which was shown to induce MHC class I expression on B16 cells and increase the lytic activity of the CD8+ CTL generated by IT-EP/IL12. The results from these animal studies may help in the development of IT-EP/IL12 for cancer patients.