Anjali Gaikwad

Utilization of an ex vivo human placental perfusion model to predict potential fetal exposure to carboplatin during pregnancy

OBJECTIVE The objective of this study was to determine the fetal drug compartment concentrations when various concentrations of carboplatin cross the placental-trophoblastic barrier and the effect on the fetal kidneys. STUDY DESIGN An ex vivo human placenta perfusion model was utilized. Term human placentae (n = 9) were collected immediately after delivery and then reperfused with plasma concentrations achieved with carboplatin an area under the curve of 5 (1000 ng/mL), 7.5 (5000 ng/mL), or 11 (11,000 ng/mL). Antipyrine was used as a reference compound. Samples were collected over 2 hours. Placental transfer was evaluated by computation of transport fraction and clearance index. Primary cells isolated by explant culture of 16-18 week old fetal organ tissues were incubated with carboplatin for up to 48 hours with untreated cell as controls. Immunohistochemical, flow cytometry analysis, and immunoblotting were applied for the expression of apoptosis-related proteins. RESULTS Mean transport fractions for carboplatin at low, middle, and high concentrations were 0.05 ± 0.02, 0.04 ± 0.01, and 0.10 ± 0.01, respectively, with clearance indexes of 0.22 ± 0.01, 0.14 ± 0.08, and 0.50 ± 0.07, respectively. The fetal peak concentrations of carboplatin achieved were 61 ± 39 ng/mL (low), 375 ± 248 ng/mL (middle), and 2081 ± 529 ng/mL (high). Fetal kidney cells exposed to carboplatin showed a concentration-dependent increased expression of apoptosis-inducing factor and p53 apoptosis proteins and a time-dependent increase in expression Bax apoptosis protein expression. Apoptosis was confirmed at the high concentration by flow cytometry. CONCLUSION Doses of carboplatin up to an area under the curve of 7.5 were not associated with significant placental transfer, fetal exposure, or fetal toxic effects. This suggests it might not be necessary to empirically reduce carboplatin doses in pregnant women.

In vitro evaluation of the effects of gefitinib on the modulation of cytotoxic activity of selected anticancer agents in a panel of human ovarian cancer cell lines

PurposeThis study was conducted to determine the in vitro optimal combination of selected anticancer agents with gefitinib and evaluate its effect on the expression of correlative biological targets in the cell-signaling pathway. In addition, the effect of gefitinib on the expression of ATP-binding cassette (ABC) transport proteins was evaluated.MethodsGrowth inhibition assays were conducted in five human ovarian cancer cell lines to evaluate the activity of selected anticancer agents in combination with gefitinib compared to each alone. Enzyme linked immunosorbant assay (ELISA) assessed the presence of pEGFR in treated and untreated cells. Expression of correlative biological targets in the cell-signaling pathway was completed by immunoblotting. RT-PCR was used to characterize the expression ABC transport proteins.ResultsThis in vitro study confirmed gefitinib did not have significant cytotoxic activity, the combination of gefitinib with other chemotherapy drugs demonstrated improved in vitro cytotoxic activity in platinum sensitive ovarian cancer cell lines. Suppression of pAKT and p-erk activation in cells treated with combination of cisplatin and gefitinib was observed and suggests the role of gefitinib inhibition of proliferative cell signaling pathway.ConclusionThis data suggests that EGFR-inhibitors, such as gefitinib, have the potential to modulate common mechanisms of drug resistance and may have a role in optimizing chemotherapy regimens for the treatment of ovarian cancer.

Determination of the optimal combination chemotherapy regimen for treatment of platinum-resistant ovarian cancer in nude mouse model

Objective. The primary objective of this study was to evaluate the potential to increase the in vivo activity of liposomal doxorubicin when administered in combination with other chemotherapeutic agents such as topotecan, docetaxel, gemcitabine, capecitabine, or celecoxib in an ovarian cancer xenograft mouse model to identify new treatment options for recurrent platinum-sensitive/resistant ovarian cancer. Methods. This was a five-arm study in two xenograft ovarian cancer mouse models, ES-2 (platinum-sensitive), and OVCAR3 (platinumresistant), to evaluate the combination of liposomal doxorubicin with the common chemotherapeutic agents. Each cell line had five mice for each treatment arm, five vehicle control mice, and five liposomal doxorubicin alone control mice. Experiments were done in duplicate. Results. The percentage tumor reduction ranged from 52% to 74.1% for the single-agent treatment arms. Tumor growth inhibition and regression (response) was improved on the combination treatment arms ranging from 76.1% to 100%.We observed increased activity in the liposomal doxorubicin plus topotecan arm, with a 27.3% improvement in response, compared with either agent alone. Conclusions. The addition of liposomal doxorubicin demonstrated increased antitumor activity compared with either agent used alone. The most active combination treatment arm was liposomal doxorubicin with topotecan which is consistent with recent clinical study reports of enhanced activity with the combination of topoisomerase I and topoisomerase II agents. Additional studies are warranted to evaluate the efficacy and safety to optimize the combination of liposomal doxorubicin and topotecan for the treatment of recurrent or refractory ovarian cancer.

In vitro evaluation of the effects of gefitinib on the cytotoxic activity of selected anticancer agents in a panel of human endometrial cancer cell lines

Purpose. This study was conducted to determine the in vitro optimal combination of selected anticancer agents with gefitinib and evaluate its effect on the expression of correlative biological targets in the cell-signaling pathway. In addition, the effect of gefitinib on the expression of ATP-binding cassette (ABC) transport proteins was evaluated. Methods. Growth inhibition assays were conducted in six human endometrial cancer cell lines to evaluate the activity of selected anticancer agents with gefitinib compared to each alone. Enzyme linked immunosorbant assay (ELISA) assessed the presence of pEGFR in treated and untreated cells. Evaluation of the suppression of correlative biological targets in the cell-signaling pathway was completed by immunoblotting. RT-PCR was used to characterize the expression of MRP and ABC transport proteins. Results. This in vitro study gefitinib did not observe cytotoxic activity as a single agent. However, the activity of gefitinib as EGFR inhibitor was confirmed. The combination of gefitinib with paclitaxel and docetaxel exhibited improved in vitro cytotoxic activity compared to each antineoplastic agent alone. Suppression of pAKT and p27 in the human endometrial cancer cells treated with selected combinations of chemotherapeutic drugs and gefitinib was observed. Conclusion. These data suggest that EGFRinhibitors, such as gefitinib, have the potential to modulate common mechanisms of drug resistance and may have a role in optimizing antineoplastic regimens for the treatment of recurrent endometrial cancer. This may represent a promising option for this class of agents in the treatment of endometrial cancer. J Oncol Pharm Practice (2009) 15: 35—44.

Evaluating the potential effect on fetal tissue after exposure to granisetron during pregnancy

The objective of this study was to elucidate the possible toxic effects on the fetal tissues after exposure to two clinically relevant concentrations of granisetron. Primary cells were isolated from human fetal organs of 16-19 weeks gestational age and treated with 3 ng/mL or 30 ng/mL of granisetron. Cell cycle progression was evaluated by flow cytometry. ELISA was used to detect alterations in major apoptotic proteins. Up to 10% apoptosis in cardiac tissue was observed following treatment with 30 ng/mL granisetron. Neither concentration of granisetron caused alteration in cell cycle progression or alterations in apoptotic proteins in any of the other tissues. At 30 ng/mL granisetron concentration had the potential to induce up to 10% apoptosis in cardiac tissue; clinical significance needs further evaluation. At granisetron 3 ng/mL there was no detectable toxicity or on any fetal tissue in this study. Further research is needed to confirm these preliminary findings and determine if clinically significant.

Assessment of Dong Quai Hepatic Metabolism and Potential Interactions when Combined with Chemotherapy

Background: Dong Quai is a common herbal supplement classified as a “phytoestrogen” used for the improvement of female reproductive function. In the oncology setting, women often seek natural approaches for managing symptoms associated with decreased hormone levels either from surgery or chemotherapy-induced. Clinically, the concern is the safety of phytoestrogens in combination with chemotherapy. The objective of this study was to characterize the hepatic metabolism of Dong Quai to define the potential for drug interactions with selected chemotherapy agents and its impact on alterations in the cytotoxicity in panel of human cancer cell lines. Methods: In vitro high through-put cytochrome P450 (CYP450) inhibition assay was performed for CYP450 2C9, 2C8, 2D6 and 3A4 isoenzymesto evaluate phase I metabolism of Dong Quai alcohol-free extract. An ex vivo hepatic induction assay with human hepatocytes was used to determine whether Dong Quai is an inducer of CYP450 isoenzymes. The potential cytotoxic effects of Dong Quai alone and its effect when combined with selected chemotherapies were evaluated by a growth inhibition assay in a panel of eight human cancer cell lines. Results: No inhibition of CYP450 was observed in presence of Dong Quai. At an estimated clinical relevant concentration of 0.86 mg/mL, Dong Quai demonstrated Quai induced CYP3A4, 2C9, 2C8 and 2D6. Dong Quaidid not demonstrated cytotoxicity by itself in the panels of eight human cancer cell lines with 50% growth inhibition was not achieved. The 25% growth inhibition was achieved at concentrations ranging from 0.39 mg/mL to 4.48 mg/mL. Combination growth inhibition assays showed decreased cytotoxic activity of chemotherapy agents. Conclusion: This data suggests that Dong Quai is an inducer of the CYP450 pathways and also decreased cytotoxic activity of selected chemotherapy. Until confirmatory in vivo information available Dong Quai should be used with caution with chemotherapy.

Defining the role of echinocandin catechol functional groups in the development of secondary hepatocellular carcinoma

OBJECTIVES To determine whether the catechol functional group on echinocandins decreases the catechol-O-methyltransferase (COMT) metabolism of catechol oestrogens (CEs) and the potential role of this functional group in the development of hepatocellular cancer. METHODS Human COMT expression was measured by RT-PCR in a panel of selected human cancer cell lines and human hepatocytes. An ex vivo human hepatocyte model was employed to evaluate the metabolism of 17-β-oestradiol to CEs in the presence of a catechol (B(0)C) versus a non-catechol echinocandin (B(0)) compound. COMT inhibition assays were conducted to evaluate the metabolism of CEs in the presence of B(0)C or B(0). Oestrogen receptor expression in human hepatic carcinoma cells was evaluated by RT-PCR and western blotting. Cell proliferation assays were used to evaluate the impact of B(0) or B(0)C on cancer cell growth. RESULTS MCF-7 and Hep-G2 cells and human hepatocytes expressed variant Met/Met COMT. At clinically relevant concentrations, only B(0)C significantly increased CE levels in the COMT inhibition assays, to 90.0 μM compared with 79.8 μM in the untreated controls (P = 0.032). A high concentration (500 μg/mL) of B(0)C decreased COMT expression to 79%, 94% and 90% of untreated, baseline control levels in the three cell lines, respectively. B(0)C and B(0) did not increase cell growth in the cancer cell lines evaluated. CONCLUSIONS At clinically achievable concentrations only B(0)C significantly inhibited COMT activity and increased CE concentrations. Short-term exposure did not alter the rate of cancer cell growth. Confirmation is needed to determine the clinical impact of long-term exposure to and the use of echinocandins with catechol functional groups.

Evaluation Fucoidan Extracts From Undaria pinnatifida and Fucus vesiculosus in Combination With Anticancer Drugs in Human Cancer Orthotopic Mouse Models

Objective: To determine the activity of fucoidan from Undaria pinnatifida (UPF) and Fucus vesiculosus (FVF) when given in combination of chemotherapy drugs using selected human breast or ovarian cancer orthotopic mouse models. Methods: Mice were inoculated with 1 × 106 cells of TOV-112d, MCF-7, or ZR-75 subcutaneously or SKOV3-GFP-Luc intraperitoneally on day 0. MCF-7 and ZR-75 mice were administered with estradiol valerate 2 mg/kg in 0.2 mL castor oil subcutaneously two days prior to cell inoculation. Mice were randomized to one of six arms (N = 10/arm) paclitaxel, UPF/paclitaxel, FVF/paclitaxel, tamoxifen, UPF/tamoxifen, or FVF/tamoxifen. Tumors were measured three times per week for 28 days. Results: Improved activity was observed with UPF or FVF in combination with tamoxifen in both the MCF-7 and ZR-75D breast cancer mouse models. Decreased activity of paclitaxel was observed when given in combination with UPF or FVF in both breast cancer mouse models. The combination of FVF/tamoxifen in the TOV-112d ovarian cancer mouse model had improved activity but no there was difference observed with the UPF/tamoxifen in either ovarian cancer mouse model. No difference was observed with combination of UPF or FVF with paclitaxel in human ovarian cancer SKOV3 or TOV-112d orthotopic mouse models. Conclusion: This study did confirm that UPF/FVF in combination with tamoxifen did not decrease tamoxifen activity in both breast and ovarian cancer, with some potential to improve activity compared to tamoxifen alone in breast cancers. Previous in vitro studies had suggested UPF and FVF had overall synergistic activity with paclitaxel; however, in the current in vivo human cancer mouse model studies there was no change in paclitaxel activity when given in combination with UPF or FVF in either of the two human ovarian cancer models. Furthermore, this study demonstrated that UPF or FVF given in combination with paclitaxel had a potential antagonistic effect in breast cancer models. Additional studies are warranted to delineate mechanisms contributing to variation in the in vivo activity when given in combination with paclitaxel. As a first step, a clinical pharmacokinetic study evaluating impact of FVF/UPF given in combination with chemotherapy in patients with solid tumors is underway.

Preclinical Evaluation of Safety of Fucoidan Extracts From Undaria pinnatifida and Fucus vesiculosus for Use in Cancer Treatment

Objectives: To evaluate potential hepatic metabolism-mediated drug interactions with fucoidan from Undaria pinnatifida (UPF) or Fucus vesiculosus (FVF) and potential growth inhibition activity with either fucoidan alone or with chemotherapy. In vivo studies were done to confirm safety and investigate fucoidan-mediated immune modulation. Methods: Cytochrome P450 (CYP450) 3A4, 2C8, 2C9, and 2D6 inhibition experiments were conducted in vitro followed by an ex vivo human hepatocytes model to evaluate the CYP450 induction potential of each fucoidan at highest theoretical concentrations. Four hepatic metabolism phase II pathways—glutathione S transferase (GST), quinone oxidoreductase (QOR), catechol-O-methyltransferases (COMT), and uridine di-phosphate (UDP)-glucuronosyltransferase (UGT)—were evaluated with validated immunoassays. Growth inhibition assays were performed with each fucoidan alone and in combination with chemotherapy agents in a panel of human cancer cell lines. In vivo studies evaluated safety and immune modualtion. Results: CYP450 inhibition was observed with FVF. The GST, QOR, and UGT pathways had no changes. UPF and FVF both interacted with COMT. No growth inhibitory activity in cancer cell lines was observed. UPF and FVF had synergistic activity with paclitaxel or tamoxifen and additive activity with topotecan. In vivo, FVF decreased HeLa human cervical tumor growth and both FVF and UPF decreased TOV-112D human ovarian tumor growth. Otherwise, no significant change in tumor growth was observed. FVF immune modulation of IgG and IL-6 was observed (p<0.03). Conclusion: At higher doses, UPF and FVF may have limited potential for drug-supplement interactions, with either CYP450 or COMT hepatic metabolism pathways. Additional studies are warranted to evaluate to confirm findings of fucoidans in combination with chemotherapy.

Evaluation of Active Hexose Correlated Compound (AHCC) in Combination With Anticancer Hormones in Orthotopic Breast Cancer Models

Objective. To determine the impact on antitumor activity when active hexose correlated compound (AHCC) in combination with anticancer hormonal agents in orthotopic mouse models of human estrogen receptor positive breast cancer and evaluate impact of AHCC on aromatase activity. Methods. The study consisted of 7 treatment arms (n=10) conducted in 2 breast cancer mouse models: MCF-7 and ZR-75. Treatment groups included untreated, vehicle, AHCC 50 mg/kg, AHCC 50 mg/kg + tamoxifen 10 mg/kg, tamoxifen 10 mg/kg, AHCC 50 mg/kg + letrozole 10 µg/mouse, or letrozole 10 µg/mouse. All treatments were administered daily by oral gavage for 12 weeks. Tumors were measured 3 times a week. In vitro estrone and 17β-estradiol enzyme immunoassay was used to evaluate aromatase activity. Results. There was no difference in the activity with the combination of AHCC + tamoxifen compared with tamoxifen (P = 0.29). In the ZR-75 model (catechol-O-methyltransferase [COMT] wild-type), there was no difference in activity with the letrozole + AHCC compared with letrozole. However, in the MCF-7 model (COMT variant), AHCC + letrozole resulted in a decrease in activity compared with letrozole (P < 0.01). Immunoassay data suggested that AHCC is a potential inducer of aromatase activity. In both tumor models, there was cytotoxicity observed with AHCC compared with untreated (P < 0.02). Conclusion. AHCC did not change the activity of tamoxifen. AHCC may have some interaction with letrozole in patients with COMT variant genotype. AHCC had cytotoxicity that warrents additional studies to evaluate its potential role for consolidation/prevention of breast cancer.