[show abstract][hide abstract] ABSTRACT: Abstract Purpose: Study distribution, pharmacokinetics, and safety of intraperitoneal (IP) (212)Pb-TCMC-trastuzumab in patients with HER-2-expressing malignancy. Experimental Design: IP (212)Pb-TCMC-trastuzumab was delivered, after 4 mg/kg intravenous (IV) trastuzumab, to 3 patients with HER-2-expressing cancer who had failed standard therapies. Patients were monitored for toxicity and pharmacokinetics/dosimetry parameters. Results: Imaging studies after 0.2 mCi/m(2) (7.4 MBq/m(2)) show little redistribution out of the peritoneal cavity and no significant uptake in major organs. Peak blood level of the radiolabeled antibody, determined by decay corrected counts, was <23% injected dose at 63 hours; maximum blood radioactivity concentration was 6.3nCi/mL at 18 hours. Cumulative urinary excretion was ≤6% in 2.3 half-lives. The maximum external exposure rate immediately post-infusion at skin contact over the abdomen averaged 7.67 mR/h and dropped to 0.67 mR/h by 24 hours. The exposure rates at the other positions monitored (axilla, chest, and femur) decreased as a function of distance from the abdomen. The data points correlate closely with (212)Pb physical decay (T1/2=10.6 hours). Follow-up >6 months showed no evidence of agent-related toxicity. Conclusions: Pharmacokinetics and imaging after 0.2 mCi/m(2) IP (212)Pb-TCMC-trastuzumab in patients with HER-2-expressing malignancy showed minimal distribution outside the peritoneal cavity, ≤6% urinary excretion, and good tolerance.
Cancer Biotherapy & Radiopharmaceuticals 12/2013; 29(1):12. · 1.44 Impact Factor
[show abstract][hide abstract] ABSTRACT: Radiation therapy (RT) kills cancer cells by causing DNA damage, and stimulates a systemic antitumor immune response by releasing tumor antigen and endogenous adjuvant within the tumor microenvironment. However, RT also induces the recruitment of immunosuppressive myeloid cells, which can interfere with the antitumor immune responses elicited by apoptotic tumor cells. We hypothesized that local delivery of vaccine following RT will lead to the priming of antigen-specific cytotoxic T lymphocyte (CTL) immune responses and render immunosuppressive myeloid cells susceptible to killing by the activated CTLs.
Using several antigenic systems, we tested whether intratumoral injection of antigenic peptide/protein in irradiated tumors would be able to prime CTLs as well as load myeloid cells with antigen, rendering them susceptible to antigen-specific CTL killing.
We show that by combining RT and targeted antigenic peptide delivery to the tumor, the adjuvant effect generated by RT itself was sufficient to elicit the priming and expansion of antigen-specific CTLs, through the type I interferon dependent pathway, leading to synergistic therapeutic antitumor effects compared to either treatment alone. In addition, using two different types of transgenic mice, we demonstrated that CTL-mediated killing of stromal cells in tumors by our approach is important for tumor control. Finally, we confirmed the efficacy of this approach in our preclinical model using two clinically tested therapeutic HPV vaccines.
These data serve as an important foundation for the future clinical translation of RT combined with a clinically tested therapeutic HPV vaccine for the control of HPV-associated cancers.
Clinical Cancer Research 12/2013; · 7.84 Impact Factor
[show abstract][hide abstract] ABSTRACT: Clinical trial endpoints have profound effects on late phase clinical trial design, results interpretation, drug development, and regulatory approval of therapeutics. Selection of the optimal clinical trial endpoint is particularly provocative in ovarian cancer where long overall survival (OS) is observed even for those who present with advanced disease stages. The lack of new regulatory approvals and the lack of harmony between regulatory bodies globally for ovarian cancer therapeutics are of concern. The advantages and disadvantages of the numerous endpoints available are herein discussed within the unique context of ovarian cancer where both crossover and post-progression therapies potentially uncouple the surrogacy between progression-free survival (PFS) and OS, the two most widely supported and utilized endpoints. The roles of patient reported outcomes (PRO) and health related quality of life (HRQoL) are discussed, but even these widely supported parameters are affected by the unique characteristics of ovarian cancer where a significant percentage of patients may be asymptomatic. Original data regarding the endpoint preferences of ovarian cancer advocates is presented. Endpoint selection in ovarian cancer clinical trials should reflect the impact on disease burden and unique characteristics of the treatment cohort while reflecting true patient benefit. Both OS and PFS have led to regulatory approvals and are clinically important. However, current regulatory approval guidance by the FDA indicates that surrogates for overall survival, while acceptable, must be clinically meaningful. OS remains the most objective and accepted endpoint because it is least vulnerable to bias; however, the feasibility of OS in ovarian cancer is compromised by the requirement for large trial size, prolonged time-line for final analysis, and potential for unintended loss of treatment effect from active post-progression therapies. A large magnitude of effect in PFS improvement should establish benefit, and further communication with regulatory authorities to clarify acceptable endpoints should be undertaken.
[show abstract][hide abstract] ABSTRACT: These NCCN Guidelines Insights focus on the major updates to the 2013 NCCN Guidelines for Ovarian Cancer. Four updates were selected based on recent important updates in the guidelines and on debate among panel members about recent clinical trials. The topics include 1) intraperitoneal chemotherapy, 2) CA-125 monitoring for ovarian cancer recurrence, 3) surveillance recommendations for less common ovarian histopathologies, and 4) recent changes in therapy for recurrent epithelial ovarian cancer. These NCCN Guidelines Insights also discuss why some recommendations were not made.
Journal of the National Comprehensive Cancer Network: JNCCN 10/2013; 11(10):1199-209. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: The goal of this report is to review the activity of promising antifolate and folate receptor agents being developed for ovarian cancer including thymidylate synthetase inhibitors, antifolate receptor antibodies, and folate-chemotherapy conjugates.
A literature search was performed over the last 5 years using the terms "folate receptor" and "ovarian cancer" and those that specifically addressed the MOA were included. Abstracts presented within the last 3 years were also searched and included in this review where appropriate.
Thymidylate synthetase inhibitors are a promising avenue for ovarian cancer treatment. Phase II trials have shown pemetrexed to have activity in patients with platinum resistant ovarian cancer. Several other thymidylate synthetase inhibitors are in the early phase of development including BGC 945 and ZD-9331. Monoclonal antibodies that target the folate receptor have also shown great potential in the development of ovarian cancer therapies. Farletuzumab is one of these antibodies. A recent phase III trial found that farletuzumab in combination with carboplatin and a taxane did not meet the study's primary endpoint of progression-free survival (PFS). The post hoc exploratory analysis showed, however, a trend toward improved PFS in some patient subsets and further analysis is ongoing. The folate receptor is also utilized through folate conjugates. Vintafolide is one such agent which is currently in phase III development. Encouraging data from phase II trials showed an improvement in PFS from 2.7mo to 5mo. Folate can also be conjugated to radioisotopes for both therapeutic and imaging purposes, and early studies have shown correlation with amount of disease to therapy response.
Folate targeted agents continue to show promising antitumor activity in ovarian malignancy and initial clinical experience has demonstrated favorable toxicity profiles. Further development and resources targeted towards these therapies appear to be warranted.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: The conditionally replicative adenovirus Ad5/3-Δ24 has a type-3 knob incorporated into the type-5 fiber that facilitates enhanced ovarian cancer infectivity. Preclinical studies have shown that Ad5/3-Δ24 achieves significant oncolysis and anti-tumor activity in ovarian cancer models. The purpose of this study was to evaluate in a Phase I trial the feasibility and safety of intraperitoneal (IP) Ad5/3-Δ24 in recurrent ovarian cancer patients. METHODS: Eligible patients were treated with IP Ad5/3-Δ24 for 3 consecutive days in one of three dose cohorts ranging 1 x 10(10)-1 x 10(12) vp. Toxicity was assessed utilizing CTC grading and efficacy with RECIST. Ascites, serum, and other samples were obtained to evaluate gene transfer, generation of wildtype virus, viral shedding, and antibody response. RESULTS: Nine of 10 patients completed treatment per protocol. A total of 15 vector-related adverse events were experienced in 5 patients. These events included fever or chills, nausea, fatigue, and myalgia. All were grade 1-2 in nature, transient, and medically managed. Of the 8 treated patients evaluable for response, six patients had stable disease and 2 patients had progressive disease. Three patients had decreased CA-125 from pretreatment levels one month after treatment. Ancillary biologic studies indicated Ad5/3-Δ24 replication in patients in the higher dose cohorts. All patients experienced an anti-adenoviral neutralizing antibody effect. CONCLUSIONS: This study suggests the feasibility and safety of a serotype chimeric infectivity-enhanced CRAd, Ad5/3-Δ24, as a potential therapeutic option for recurrent ovarian cancer patients.
[show abstract][hide abstract] ABSTRACT: We have previously created a potent DNA vaccine encoding calreticulin linked to the human papillomavirus (HPV) oncogenic protein E7 (CRT/E7). While treatment with the CRT/E7 DNA vaccine generates significant tumor-specific immune responses in vaccinated mice, the potency with the DNA vaccine could potentially be improved by co-administration of a histone deacetylase inhibitor (HDACi) as HDACi has been shown to increase the expression of MHC class I and II molecules. Thus, we aimed to determine whether co-administration of a novel HDACi, AR-42, with therapeutic HPV DNA vaccines could improve the activation of HPV antigen-specific CD8(+) T cells, resulting in potent therapeutic antitumor effects. To do so, HPV-16 E7-expressing murine TC-1 tumor-bearing mice were treated orally with AR-42 and/or CRT/E7 DNA vaccine via gene gun. Mice were monitored for E7-specific CD8(+) T cell immune responses and antitumor effects. TC-1 tumor-bearing mice treated with AR-42 and CRT/E7 DNA vaccine experienced longer survival, decreased tumor growth, and enhanced E7-specific immune response compared to mice treated with AR-42 or CRT/E7 DNA vaccine alone. Additionally, treatment of TC-1 cells with AR-42 increased the surface expression of MHC class I molecules and increased the susceptibility of tumor cells to the cytotoxicity of E7-specific T cells. This study indicates the ability of AR-42 to significantly enhance the potency of the CRT/E7 DNA vaccine by improving tumor-specific immune responses and antitumor effects. Both AR-42 and CRT/E7 DNA vaccines have been used in independent clinical trials; the current study serves as foundation for future clinical trials combining both treatments in cervical cancer therapy. KEY MESSAGE: AR-42, a novel HDAC inhibitor, enhances potency of therapeutic HPV DNA vaccines AR-42 treatment leads to strong E7-specific CD8+ T cell immune responses AR-42 improves tumor-specific immunity and antitumor effects elicited by HPV DNA vaccine AR-42 is more potent than clinically available HDACi in combination with HPV DNA vaccine.
Journal of Molecular Medicine 05/2013; · 4.77 Impact Factor
[show abstract][hide abstract] ABSTRACT: Despite the conventional treatments of radiation therapy and chemotherapy, the 5-year survival rates for patients with advanced-stage cervical cancers remain low. Cancer immunotherapy has emerged as an alternative, innovative therapy that may improve survival. Here, we utilize a preclinical HPV-16 E6/E7-expressing tumor model, TC-1, and employ the chemotherapeutic agent cisplatin to generate an accumulation of CD11c+ dendritic cells in tumor loci making it an ideal location for the administration of therapeutic vaccines. Following cisplatin treatment, we tested different routes of administration of a therapeutic HPV vaccinia vaccine encoding HPV-16 E7 antigen (CRT/E7-VV). We found that TC-1 tumor-bearing C57BL/6 mice treated with cisplatin and intratumoral injection of CRT/E7-VV significantly increased E7-specific CD8+ T cells in the blood and generated potent local and systemic antitumor immune responses compared to mice receiving cisplatin and CRT/E7-VV intraperitoneally or mice treated with cisplatin alone. We further extended our study using a clinical grade recombinant vaccinia vaccine encoding HPV-16/18 E6/E7 antigens (TA-HPV). We found that intratumoral injection with TA-HPV following cisplatin treatment also led to increased E7-specific CD8+ T cells in the blood as well as significantly decreased tumor size compared to intratumoral injection with wild type vaccinia virus. Our study has strong implications for future clinical translation using intratumoral injection of TA-HPV in conjunction with the current treatment strategies for patients with advanced cervical cancer.
Cancer Immunology and Immunotherapy 04/2013; · 3.64 Impact Factor
[show abstract][hide abstract] ABSTRACT: Multiple classes of pharmacologic agents have the potential to induce the expression and release of pro-inflammatory factors from dying tumor cells. As a result, these cells can in theory elicit an immune response through various defined mechanisms to permanently eradicate disseminated cancer. However, the impact of chemotherapy on the tumor-specific immune response in the context of the tumor microenvironment is largely unknown. Within the tumor microenvironment, the immune response promoted by chemotherapy is antagonized by an immune-suppressive milieu, and the balance of these opposing forces dictates the clinical course of disease. Here we report that high antigen exposure within the tumor microenvironment following chemotherapy is sufficient to skew this balance in favor of a productive immune response. In elevating antigen exposure, chemotherapy can achieve long-term control of tumor progression without the need of an additional adjuvant. We found that chemotherapy initiated this phenomenon in the tumor microenvironment through an accumulation of dendritic cells, which stimulated CD8+ T cells and the type-I interferon pathway. From this conceptual base, we developed a simple approach to cancer therapy combining chemotherapy and vaccination that may be widely applicable.
[show abstract][hide abstract] ABSTRACT: The cellular development of resistance to chemotherapy contributes to the high mortality noted in patients affected by ovarian cancer. Novel compounds that specifically target cellular drug resistance in ovarian cancer are therefore highly desired. Previous epidemiological studies indicate that consumption of green tea and cruciferous vegetables is inversely associated with occurrence of ovarian cancer. Therefore revealing the effects and mechanisms of major components of green tea (epigallocatechin gallate, EGCG) and cruciferous vegetables (sulforaphane, SFN) on ovarian cancer cells will provide necessary knowledge for developing potential novel treatments for the disease. In this study, EGCG or SFN was used to treat both paclitaxel-sensitive (SKOV3-ip1) and -resistant (SKOV3TR-ip2) ovarian cancer cell lines alone or in combination. We found that SFN inhibits cell viability of both ovarian cancer cell lines time- and dose-dependently and that EGCG potentiates the inhibiting effect of SFN on ovarian cancer cells. Cell cycle analysis indicates SFN can arrest ovarian cancer cells in G2/M phase, while EGCG and SFN co-treatment can arrest cells in both G2/M and S phase. Combined EGCG and SFN treatment increases apoptosis significantly in paclitaxel-resistant SKOV3TR-ip2 cells after 6 days of treatment, while reducing the expression of hTERT, the main regulatory subunit of telomerase. Western blotting also indicates that SFN can down-regulate Bcl-2 (a gene involved in anti-apoptosis) protein levels in both cell types. Cleaved poly(ADP-ribose) polymerase (PARP) becomes up-regulated by 6 days of treatment with SFN and this is more pronounced for combination treatment indicating induction of apoptosis. Furthermore, phosphorylated H2AX is up-regulated after 6 days of treatment with SFN alone, and EGCG can potentiate this effect, suggesting that DNA damage is a potential cellular mechanism contributing to the inhibiting effect of EGCG and SFN combination treatment. Taken together, these results indicate that EGCG and SFN combination treatment can induce apoptosis by down-regulating of hTERT and Bcl-2 and promote DNA damage response specifically in paclitaxel-resistant ovarian cancer cell lines and suggest the use of these compounds for overcoming paclitaxel resistance in ovarian cancer treatment.
Experimental Cell Research 01/2013; · 3.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: Identification of associations between global DNA methylation and excess body weight (EBW) and related diseases and their modifying factors are an unmet research need that may lead to decreasing DNA methylation-associated disease risks in humans. The purpose of the current study was to evaluate the following; 1) Association between the degree of peripheral blood mononuclear cell (PBMC) L1 methylation and folate, and indicators of EBW, 2) Association between the degree of PBMC L1 methylation and folate, and insulin resistance (IR) as indicated by a higher homeostasis model assessment (HOMA-IR).
The study population consisted of 470 child-bearing age women diagnosed with abnormal pap. The degree of PBMC L1 methylation was assessed by pyrosequencing. Logistic regression models specified indicators of EBW (body mass index-BMI, body fat-BF and waist circumference-WC) or HOMA-IR as dependent variables and the degree of PBMC L1 methylation and circulating concentrations of folate as the independent predictor of primary interest.
Women with a lower degree of PBMC L1 methylation and lower plasma folate concentrations were significantly more likely to have higher BMI, % BF or WC (OR = 2.49, 95% CI:1.41-4.47, P = 0.002; OR = 2.49, 95% CI:1.40-4.51, P = 0.002 and OR = 1.98, 95% = 1.14-3.48 P = 0.0145, respectively) and higher HOMA-IR (OR = 1.78, 95% CI:1.02-3.13, P = 0.041).
Our results demonstrated that a lower degree of PBMC L1 methylation is associated with excess body weight and higher HOMA-IR, especially in the presence of lower concentrations of plasma folate.
PLoS ONE 01/2013; 8(1):e54544. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Advanced-stage ovarian cancer is characterized by high mortality due to development of resistance to conventional chemotherapy. Novel compounds that can enhance the efficacy of conventional chemotherapy in ovarian cancer may overcome this drug resistance. Consumption of green tea (epigallocatechin gallate, EGCG) and cruciferous vegetables (sulforaphane, SFN) is inversely associated with occurrence of ovarian cancer and has anticancer effects through targeting multiple molecules in cancer cells. However, the effects of EGCG and SFN combinational treatment on ovarian cancer cells and on efficacy of cisplatin to these cells are unknown. In this study, EGCG or SFN was used to treat both cisplatin-sensitive (A2780) and cisplatin-resistant (A2780/CP20) ovarian cancer cells alone or in combination with cisplatin. We found that EGCG and SFN combinational treatment can reduce cell viability of both ovarian cancer cell lines time- and dose-dependently. Furthermore, EGCG and SFN combinational treatment can enhance cisplatin-induced apoptosis and G2/M phase arrest, thereby enhancing the efficacy of cisplatin on both cisplatin-sensitive and cisplatin-resistant ovarian cancer cells. EGCG and SFN combinational treatment upregulated p21 expression induced by cisplatin in cisplatin-sensitive ovarian cancer cells, while p27 expression was not regulated by these treatments. Collectively, these studies provide novel approaches to overcoming cisplatin chemotherapy resistance in ovarian cancer.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: Erythropoiesis-stimulating agents (ESAs) support chemotherapy-induced anemia in patients with epithelial ovarian cancer (EOC). In response to research demonstrating that ESAs increase tumor growth and shorten survival, the Food and Drug Administration mandated the new APPRISE (Assisting Providers and Cancer Patients with Risk Information for the Safe use of ESAs) guidelines for consenting patients before ESAs administration. We sought to quantify the change in ESA and red blood cell (RBC) transfusion use after the APPRISE mandate was instituted. METHODS/MATERIALS: After institutional review board approval, a retrospective chart review compared patients with EOC undergoing chemotherapy before and after the APPRISE mandate. Abstracted data included patient demographics, chemotherapy treatment status and regimen, and number of patients requiring ESAs or RBCs. A cost savings analysis was also performed. RESULTS: Eighty-four patients who underwent 367 cycles of chemotherapy after the APPRISE guidelines were compared with a matched set of 88 patients receiving 613 cycles of chemotherapy before the APPRISE guidelines. There were no statistically significant differences between the groups. Most patients had advanced stage disease and received primary taxane-/platinum-based chemotherapy. Of 88 patients, 45 (51%) in the pre-APPRISE group received a total of 196 ESA injections compared with 0 patients in the post-APPRISE group. Red blood cell transfusion in the post-APPRISE group was similar to that in the pre-APPRISE group (8.3% vs 14.8%, P = 0.28). Omission of ESAs in the post-APPRISE group resulted in a roughly $700,000 savings in billable charges. CONCLUSIONS: In our institution, the APPRISE guidelines have resulted in complete cessation of the use of ESAs in patients with primary or recurrent EOC, resulting in considerable cost savings. Importantly, RBC transfusion rates did not significantly increase after the guidelines were imposed.
International Journal of Gynecological Cancer 12/2012; · 1.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: Introduction: Identification of human papillomavirus (HPV) as the etiologic factor of cervical, anogenital, and a subset of head and neck cancers has stimulated the development of preventive and therapeutic HPV vaccines to control HPV-associated malignancies. Excitement has been generated by the commercialization of two preventive L1-based vaccines, which use HPV virus-like particles (VLPs) to generate capsid-specific neutralizing antibodies. However, factors such as high cost and requirement for cold chain have prevented widespread implementation where they are needed most. Areas covered: Next generation preventive HPV vaccine candidates have focused on cost-effective stable alternatives and generating broader protection via targeting multivalent L1 VLPs, L2 capsid protein, and chimeric L1/L2 VLPs. Therapeutic HPV vaccine candidates have focused on enhancing T cell-mediated killing of HPV-transformed tumor cells, which constitutively express HPV-encoded proteins, E6 and E7. Several therapeutic HPV vaccines are in clinical trials. Expert opinion: Although progress is being made, cost remains an issue inhibiting the use of preventive HPV vaccines in countries that carry the majority of the cervical cancer burden. In addition, progression of therapeutic HPV vaccines through clinical trials may require combination strategies employing different therapeutic modalities. As research in the development of HPV vaccines continues, we may generate effective strategies to control HPV-associated malignancies.
Expert Opinion on Emerging Drugs 11/2012; · 2.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: These NCCN Guidelines Insights focus on the major updates for the 2012 NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Ovarian Cancer by describing how and why the new recommendations were made. The 6 update topics were selected based on recent important updates in the guidelines and on debate among panel members about recent clinical trials, and include: 1) screening, 2) diagnostic tests for assessing pelvic masses, 3) primary treatment using neoadjuvant chemotherapy, 4) primary adjuvant treatment using bevacizumab in combination with chemotherapy, 5) therapy for recurrent disease, and 6) management of drug/hypersensitivity reactions. These NCCN Guidelines Insights also discuss why some recommendations were not made (eg, panel members did not feel the new data warranted changing the guideline). See "Updates" in the NCCN Guidelines for Ovarian Cancer for a complete list of all the recent revisions.
Journal of the National Comprehensive Cancer Network: JNCCN 11/2012; 10(11):1339-1349. · 5.11 Impact Factor
[show abstract][hide abstract] ABSTRACT: Persistence of human papillomavirus (HPV) infection is necessary for the development of cervical cancer. Additionally, infection with HPV is implicated in the majority of cases of other genital tract malignancies including vulvar, penile, and vaginal cancer. HPV testing and vaccination are a routine part of obstetrical/gynecological clinical practice. With an enhanced public awareness of HPV infections, many patients turn to their obstetricians/gynecologists with questions about transmission, testing, and prevention. In this review, we will discuss the biology of HPV, epidemiology of disease, methods and indications for testing, and vaccination strategies.
American journal of obstetrics and gynecology 09/2012; · 3.28 Impact Factor
[show abstract][hide abstract] ABSTRACT: Targeting the tumor stroma in addition to the malignant cell compartment is of paramount importance to achieve complete tumor regression. In this work, we modified a previously designed tumor stroma-targeted conditionally replicative adenovirus (CRAd) based on the SPARC promoter by introducing a mutated E1A unable to bind pRB and pseudotyped with a chimeric Ad5/3 fiber (Ad F512v1), and assessed its replication/lytic capacity in ovary cancer in vitro and in vivo. AdF512v1 was able to replicate in fresh samples obtained from patients: (i) with primary human ovary cancer; (ii) that underwent neoadjuvant treatment; (iii) with metastatic disease. In addition, we show that four intraperitoneal (i.p.) injections of 5 × 10(10) v.p. eliminated 50% of xenografted human ovary tumors disseminated in nude mice. Moreover, AdF512v1 replication in tumor models was enhanced 15-40-fold when the tumor contained a mix of malignant and SPARC-expressing stromal cells (fibroblasts and endothelial cells). Contrary to the wild-type virus, AdF512v1 was unable to replicate in normal human ovary samples while the wild-type virus can replicate. This study provides evidence on the lytic capacity of this CRAd and highlights the importance of targeting the stromal tissue in addition to the malignant cell compartment to achieve tumor regression.Molecular Therapy (2012); doi:10.1038/mt.2012.147.
[show abstract][hide abstract] ABSTRACT: The hedgehog pathway has been implicated in the formation and maintenance of a variety of malignancies, including ovarian cancer; however, it is unknown whether hedgehog signaling is involved in ovarian cancer chemoresistance. The goal of this study was to determine the effects of antagonizing the hedgehog receptor, Smoothened (Smo), on chemotherapy response in ovarian cancer. Expression of hedgehog pathway members was assessed in three pairs of parental and chemotherapy-resistant ovarian cancer cell lines (A2780ip2/A2780cp20, SKOV3ip1/SKOV3TRip2, HeyA8/HeyA8MDR) using quantitative PCR and Western blot analysis. Cell lines were exposed to increasing concentrations of two different Smo antagonists (cyclopamine, LDE225) alone and in combination with carboplatin or paclitaxel. Selective knockdown of Smo, Gli1, or Gli2 was achieved using siRNA constructs. Cell viability was assessed by MTT assay. A2780cp20 and SKOV3TRip2 orthotopic xenografts were treated with vehicle, LDE225, paclitaxel, or combination therapy. Chemoresistant cell lines showed higher expression (>2-fold, P < 0.05) of hedgehog signaling components compared with their respective parental lines. Smo antagonists sensitized chemotherapy-resistant cell lines to paclitaxel, but not to carboplatin. LDE225 treatment also increased sensitivity of ALDH-positive cells to paclitaxel. A2780cp20 and SKOV3TRip2 xenografts treated with combined LDE225 and paclitaxel had significantly less tumor burden than those treated with vehicle or either agent alone. Increased taxane sensitivity seems to be mediated by a decrease in P-glycoprotein (MDR1) expression. Selective knockdown of Smo, Gli1, or Gli2 all increased taxane sensitivity. Smo antagonists reverse taxane resistance in chemoresistant ovarian cancer models, suggesting combined anti-hedgehog and chemotherapies could provide a useful therapeutic strategy for ovarian cancer.
Molecular Cancer Therapeutics 05/2012; 11(7):1587-97. · 5.60 Impact Factor