No abstract

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...

No abstract

This study was conducted to investigate the effect of drying in antioxidant activity and to compare the changes of ascorbic acid and colour by drying and storage in Korean red pepper. The antioxidant activity of red pepper dried by modified method (MM, dried at 70°C/6 h in cut pods) was about threefold higher than those dried by conventional method (CM, dried at 80°C/5 h followed by 60°C/18 h in whole pods) in the ([2,2¢-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid)] (ABTS) and (2,2-diphenyl-1-picrylhydrazyl) (DPPH) radical-scavenging assays, respectively. The ascorbic acid contents in MM and CM drying were 12.41 ± 2.15 mg g )1 and 3.05 ± 0.39 mg g )1 , and were not changed for 3 months at 0°C in red pepper dried by MM. The ASTA colour values of red pepper dried by MM and CM were 114.0 and 107.4, respectively. For 6-month storage, 72-85% of the colour was retained regardless of drying and storage conditions.

The development of therapeutic vaccines has important implications for the treatment of cancer patients. Here we investigate whether human papillomavirus (HPV) E7 subunit vaccines can enhance tumor radioresponse using an established cervical cancer animal model. Radiation plus E7 subunit vaccines improved complete response, cure, and recurrence rates of tumors dramatically compared with single therapy alone. In particular, both components of the E7 subunit vaccines (E7 protein and CpG-oligodeoxynucleotide) were required for the induction of antigen (Ag)-specific cytotoxic T-lymphocyte (CTL) responses and for therapeutic synergy with radiotherapy. Moreover, with combined therapy the radiation dose could be reduced by 16 Gy to achieve an equivalent anti-tumor efficacy to radiation treatment alone. This therapeutic synergy was found to be mediated by CD8(+) CTLs and was concomitant with histological changes (presence of apoptotic bodies and multinucleated giant cells; heavy infiltration of lymphocytes), as determined by in vivo T-cell depletion and histological analysis. Finally, phenotypic changes of radiated tumors and their increased sensitivity to CTL-mediated killing appeared to be responsible for therapeutic synergy. These results show that E7 subunit vaccines act as a potent enhancer of tumor radioresponse and that this is mediated by increased sensitivity of radiated tumors to CTL-mediated killing. This study further suggests that E7-targeted therapeutic vaccines have the potential to improve radiotherapy in patients with cervical cancer.