Biomedical subjects

Philip A Philip

Publications and source records attributed to Philip A Philip.

At least 19 recordsLinked to original sources

PubMed2006

Phase I study of bryostatin 1 and gemcitabine.

PURPOSE: Bryostatin 1 is a macrocyclic lactone with protein kinase C inhibitory activity. Gemcitabine is a nucleotide analogue with a broad spectrum of anticancer activity. Bryostatin 1 enhanced the activity of antitumor agents including gemcitabine in preclinical models. The primary objective of this phase I study was to determine the recommended doses for phase II trials of bryostatin 1 and gemcitabine. EXPERIMENTAL DESIGN: Eligible patients had histologic or cytologic diagnosis of nonhematologic cancer refractory to conventional treatment; life expectancy of >3 months; normal renal, hepatic, and bone marrow function; and a Southwest Oncology Group performance status of 0 to 2. Gemcitabine was administered i.v. over 30 minutes and was followed by bryostatin 1 by i.v. infusion over 24 hours on days 1, 8, and 15 of a 28-day cycle. Bryostatin 1 (microg/m(2)) and gemcitabine (mg/m(2)) doses were escalated as follows: 25/600, 25/800, 25/1,000, 30/1,000, 35/1,000, and 45/1,000, respectively. RESULTS: Thirty-six patients (mean age, 57 years; male/female 15:21) were treated. The median number of treatment cycles per patient was 3 (range, 0-24). Four patients developed dose limiting toxicities: myalgia, 2; myelosuppression, 1; and elevation of serum alanine aminotransferase levels, 1. Ten grade 3 toxicities were observed (anemia, 2; neutropenia, 5; thrombocytopenia, 3). No treatment-related death was seen. The recommended doses for phase II trials for bryostatin 1 and gemcitabine were 35 microg/m(2) and 1,000 mg/m(2), respectively. Two heavily pretreated patients with breast and colon cancer experienced partial responses lasting 22 and 8 months, respectively. Eight patients had stable disease. CONCLUSION: The combination of bryostatin 1 and gemcitabine seemed to be well tolerated with limited grade 3 toxicity. The recommended dose of bryostatin 1 in combination with full doses of gemcitabine was 35 microg/m(2).

Adolescent↗

PubMed2006

Potentiation of the effect of erlotinib by genistein in pancreatic cancer: the role of Akt and nuclear factor-kappaB.

The epidermal growth factor receptor (EGFR) is a target of new therapies in most nonhematologic cancers. EGFR blockade alone may not be sufficient for the control of growth and invasion of human pancreas cancer because of the independent activation of Akt and nuclear factor-kappaB (NF-kappaB). The expression of EGFR, Akt, and NF-kappaB was determined in six human pancreatic cancer cell lines. Selected cells for specific expression were treated with erlotinib, genistein, gemcitabine, or the combination. Growth inhibition was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and apoptosis was assayed by ELISA. EGFR, phosphorylated EGFR, phosphorylated Akt, and survivin expressions were determined by immunoblotting. Electrophoretic mobility shift assay was used to evaluate the DNA binding activity of NF-kappaB. Genistein significantly increased (P < 0.05) erlotinib-induced growth inhibition and apoptosis in BxPC-3, CAPAN-2, and AsPC-1 cells. In the BxPC-3 cell line, significant down-regulation of EGFR, phosphorylated Akt, NF-kappaB activation, and survivin was observed in the cells treated with the combination compared with the erlotinib-treated cells. In the HPAC and MIAPaCa cell line, no potentiation of the effects of erlotinib by genistein on cell growth or inhibition of the EGFR/Akt/NF-kappaB was observed. Genistein potentiated growth inhibition and apoptosis of the gemcitabine and erlotinib combination in COLO-357 cell line. Genistein potentiates the growth inhibition and apoptosis induced by erlotinib and gemcitabine in certain pancreatic cancer cells. Akt and NF-kappaB inhibition represents one of the mechanisms for the potentiation of erlotinib- and gemcitabine-induced cell death by genistein.

Apoptosis↗

PubMed2006

Consensus report of the international society of gastrointestinal oncology on therapeutic progress in advanced pancreatic cancer.

Since 1997, when gemcitabine showed superior clinical benefit to single-agent 5-fluorouracil, it has remained the standard of care for the treatment of advanced pancreatic cancer. Numerous new agents, both cytotoxic and targeted, have been tested against this standard. Some trials showed improved response rates or progression free survival, but there was no clear improvement in survival. For the current report, those trial results were reviewed in depth for methodology, endpoints, and study characteristics. More recent studies have shown progress. Studies with combinations of gemcitabine and capecitabine and with the epidermal growth factor receptor antagoinist, erlotinib, have demonstrated survival benefits. Currently, studies of combinations with oxaliplatin, bevacizumab, and cetuximab are ongoing. Other targeted therapies also are considered for future clinical trials. Based on a comprehensive review of past trials, a consensus on endpoints in the treatment of pancreatic cancer and an approach to new trials is presented.

Antineoplastic Agents↗

PubMed2006

Phase II study of erlotinib in patients with advanced biliary cancer.

PURPOSE: Epidermal growth factor receptor/human epidermal growth factor receptor 1 and ligand expression is common in biliary cancers (BILI) and may be associated with worse outcome. The primary objective of this study was to determine the proportion of patients with advanced BILI who were progression-free at 6 months. METHODS: Patients with either unresectable or metastatic disease were studied. Only one prior systemic or locoregional therapy was allowed. Erlotinib was administered continuously at a dose of 150 mg per day orally. RESULTS: Forty-two patients with BILI were enrolled. The median age was 67 years (range, 33 to 82 years). Fifty-two percent of patients had Eastern Cooperative Oncology Group performance status of 1. Fifty-seven percent of patients had received prior chemotherapy for advanced BILI. HER1/EGFR expression by immunohistochemistry in tumor cells was detected in 29 (81%) of the 36 assessable patients. Seven of the patients (17%; 95% CI, 7% to 31%) were progression free at 6 months. Three patients had partial response by Response Evaluation Criteria in Solid Tumors Group classification of duration 4, 4, and 14 months, respectively. All responding patients had mild (grade 1/2) skin rash and two patients had positive tumoral HER1/EGFR expression. Three patients (7%) had toxicity-related dose reductions of erlotinib due to grade 2/3 skin rash. CONCLUSION: Results suggest a therapeutic benefit for EGFR blockade with erlotinib in patients with biliary cancer. Additional studies with erlotinib as a single agent and in combination with other targeted agents are warranted in this disease.

Adult↗

PubMed2006

A multi-institutional phase II trial of preoperative full-dose gemcitabine and concurrent radiation for patients with potentially resectable pancreatic carcinoma.

BACKGROUND: We report the results of a multi-institutional phase II trial that used preoperative full-dose gemcitabine and radiotherapy for patients with potentially resectable pancreatic carcinoma. METHODS: Patients were treated before surgery with three cycles of full-dose gemcitabine (1000 mg/m2 intravenously), with radiation during the second cycle (36 Gy in daily 2.4-Gy fractions). Patients underwent surgery 4 to 6 weeks after the last gemcitabine infusion. RESULTS: There were 10 men and 10 women, with a median age of 58 years (range, 50-80 years). Nineteen patients (95%) completed therapy without interruption, and one experienced grade 3 gastrointestinal toxicity. The mean weight loss after therapy was 4.0%. Of 20 patients taken to surgery, 17 (85%) underwent resections (16 pancreaticoduodenectomies and 1 distal pancreatectomy). The complication rate was 24%, with an average length of stay of 13.5 days. There were no operative deaths. Pathologic analysis revealed clear margins in 16 (94%) of 17 and uninvolved lymph nodes in 11 (65%) of 17 specimens. One specimen contained no residual tumor, and three specimens revealed only microscopic foci of residual disease. With a median follow-up of 18 months, 7 (41%) of the 17 patients with resected disease are alive with no recurrence, 3 (18%) are alive with distant metastases, and 7 (41%) have died. CONCLUSIONS: Preoperative gemcitabine/radiotherapy is well tolerated and safe when delivered in a multi-institutional setting. This protocol had a high rate of subsequent resection, with acceptable morbidity. The high rate of negative margins and uninvolved nodes suggests a significant tumor response. Preliminary survival data are encouraging. This regimen should be considered in future neoadjuvant trials for pancreatic cancer.

Aged↗

PubMed2006

A phase I study of flavopiridol and docetaxel.

BACKGROUND: Flavopiridol is a cyclin dependent kinase inhibitor. Preclinical models suggest a sequence dependent synergy between flavopiridol and taxanes. The primary objective of this study was to determine the maximum tolerated dose (MTD) of flavopiridol and docetaxel and the influence of flavopiridol on the pharmacokinetics of docetaxel. METHODS: The major eligibility criteria included: a diagnosis of non-hematologic cancer with no conventional effective therapy, normal organ function, and ECOG performance status of 0-2. Patients were treated with docetaxel followed 24 h later by flavopiridol given via continuous intravenous infusion over a 24-h period. The starting doses of docetaxel and flavopiridol were 60 and 60 mg/m2, respectively. Cycles were repeated every 21 days. All patients received diarrhea prophylaxis consisting of bismuth subsalicylate. RESULTS: Ten patients (M:F 4:6; median age 56 years) were treated. The median number of cycles per patient was 2 (range 1-6). Two of the three patients on dose level 1 developed dose-limiting toxicities consisting of neutropenia and fever. Seven patients were subsequently enrolled on dose level -1 (docetaxel 60 mg/m2, flavopiridol 50 mg/m2). One episode of grade 3 diarrhea was reported at dose level -1. CONCLUSIONS: Neutropenia complicated by infection was the major dose-limiting toxicity. The recommended doses of flavopiridol and docetaxel for phase II trials are 50 and 60 mg/m2 every three weeks, respectively.

Antineoplastic Agents, Phytogenic↗

PubMed2006

A phase II study of docetaxel, doxorubicin, and infusional 5-fluorouracil in the treatment of patients with locally advanced breast cancer.

OBJECTIVE: The primary aim of this study was to estimate the rate of clinical and pathologic response to preoperative docetaxel, doxorubicin, and infusional 5-fluorouracil in patients with locally advanced breast cancer. Secondary objective included the determination of toxicity profile. PATIENTS AND METHODS: Thirty-nine patients (median age 49 years) with histologically confirmed locally advanced breast cancer (stage IIIA or IIIB) were studied. Patients received 4 courses of chemotherapy with docetaxel (75 mg/m2 iv over 1 hour), doxorubicin (50 mg/m2 iv bolus), and 5-fluorouracil (300 mg/m2/d as continuous iv infusion on days 1-5). Treatment cycles were repeated every 21 days. Prophylactic filgastrim 5 microg/kg s/c QD was administered to all patients. Definitive surgery was performed after the completion of 4 cycles of therapy. Pathologic complete response was defined as the absence of invasive cancer in both the breast and ipsilateral axillary lymph nodes. RESULTS: The clinical objective response rate (partial plus complete) was 87% (95% confidence interval [CI]: 76-98%). Three patients (8%) had complete pathologic response. Two patients progressed preoperatively. Thirteen patients (33%) developed neutropenic fever. Fifty-three percent of the patients were hospitalized for treatment related complications. No cardiotoxicity or treatment related deaths were observed. CONCLUSIONS: Triple cytotoxic therapy based on concurrent doxorubicin and docetaxel with infusional 5-flourouracil (5-FU) does not appear to significantly improve the pathologic response in patients with locally advanced breast cancer.

Adult↗

PubMed2005

Molecular evidence for increased antitumor activity of gemcitabine by genistein in vitro and in vivo using an orthotopic model of pancreatic cancer.

Soy isoflavone genistein exhibits growth inhibitory activity against human pancreatic cancer cell lines. We previously reported the potential of genistein to augment chemotherapeutic response of pancreatic cancer cells in vitro. In the present study, we investigated whether genistein pretreatment could be used as a novel strategy for gemcitabine-induced killing in vitro and enhanced antitumor activity in vivo using an orthotopic tumor model. We conducted our studies using paired isogenic human pancreatic cancer cell line with differences in metastatic behavior (COLO 357 and L3.6pl). In vitro studies were done to measure growth inhibition and degree of apoptotic cell death induced by either genistein alone, gemcitabine alone, or genistein followed by gemcitabine. Our results show that pretreatment of cells with genistein for 24 hours followed by gemcitabine resulted in 60% to 80% growth inhibition compared with 25% to 30% when gemcitabine was used alone. The overall growth inhibition was directly correlated with apoptotic cell death irrespective of the metastatic potential of cells. Several genes that are known to inhibit apoptosis and contribute to chemoresistance such as nuclear factor-kappaB (NF-kappaB) and Akt were assessed to investigate the basis for the observed chemosensitizing effects of genistein. Genistein potentiated the gemcitabine-induced killing by down-regulation of NF-kappaB and Akt. In contrast, Akt and NF-kappaB were found to be up-regulated when pancreatic cancer cells were exposed to gemcitabine alone, suggesting the potential mechanism of acquired chemoresistance. In addition to in vitro results, we show here for the first time, that genistein in combination with gemcitabine is much more effective as an antitumor agent compared with either agent alone in our orthotopic tumor model. But most importantly, our data also showed that a specific target, such as NF-kappaB, was inactivated in genistein-treated animal tumors and that gemcitabine-induced activation of NF-kappaB was completely inhibited in animal tumors treated with genistein and gemcitabine. These results provide strong molecular in vivo evidence in support of our hypothesis that inactivation of NF-kappaB signaling pathway by genistein could also abrogate gemcitabine-induced activation of NF-kappaB resulting in the chemosensitization of pancreatic tumors to gemcitabine, which is likely to be an important and novel strategy for the treatment of pancreatic cancer.

Animals↗

PubMed2005

Phase II study of Erlotinib (OSI-774) in patients with advanced hepatocellular cancer.

PURPOSE: Epidermal growth factor receptor/human epidermal growth factor receptor 1 (EGFR/HER1) and ligand expression is frequently seen in hepatocellular cancers (HCCs). Erlotinib (Tarceva, OSI-774; OSI Pharmaceuticals, Melville, NY) is a receptor tyrosine kinase inhibitor with specificity for the EGFR/HER1. METHODS: The primary objective of this study was to determine the proportion of patients with advanced HCC who were progression-free at 6 months. Patients with either unresectable or metastatic disease were studied. Only one prior systemic or locoregional therapy was allowed. Erlotinib was given continuously at a dose of 150 mg per day orally. RESULTS: Thirty-eight patients with HCC were enrolled. Median age of the patients was 69 years (range, 27 to 83 years). A majority of patients (63%) had an Eastern Cooperative Oncology Group performance status of 1. Forty-seven percent of patients had received prior chemotherapy for advanced HCC. EGFR/HER1 expression was detected in 88% of the patients. Median number of cycles per patient was two (range, 1 to 26). Twelve (32%; CI 95%, 18 to 49) of the 38 patients with HCC were progression-free at 6 months. Three patients had partial radiologic responses of duration of 2, 10, and 11 months, respectively. Disease control was seen in 59% of the patients. Median overall survival time was 13 months. Ten patients (26%) had toxicity-related dose reductions of erlotinib. Grade 3/4 skin toxicity or diarrhea was encountered in five and three patients, respectively. CONCLUSION: Results of this trial suggest a benefit for EGFR/HER1 blockade with erlotinib in patients with HCC manifested by disease control. Additional studies with erlotinib as a single agent or in combination with other agents are warranted.

Administration, Oral↗

PubMed2005

Inactivation of nuclear factor kappaB by soy isoflavone genistein contributes to increased apoptosis induced by chemotherapeutic agents in human cancer cells.

Cancer chemotherapeutic strategies commonly require multiple agents. However, use of multiple agents contributes to added toxicity resulting in poor treatment outcome. Thus, combination chemotherapy must be optimized to increase tumor response and at the same time lower its toxicity. Chemotherapeutic agents are known to induce nuclear factor kappaB (NF-kappaB) activity in tumor cells, resulting in lower cell killing and drug resistance. In contrast, genistein has been shown to inhibit the activity of NF-kappaB and the growth of various cancer cells without causing systemic toxicity. We therefore investigated whether the inactivation of NF-kappaB by genistein before treatment of various cancer cells with chemotherapeutic agents could lead to better tumor cell killing as tested by in vitro studies using gene transfections and also by animal studies. PC-3 (prostate), MDA-MB-231 (breast), H460 (lung), and BxPC-3 (pancreas) cancer cells were pretreated with 15 to 30 micromol/L genistein for 24 hours and then exposed to low doses of chemotherapeutic agents for an additional 48 to 72 hours. We found that 15 to 30 micromol/L genistein combined with 100 to 500 nmol/L cisplatin, 0.5 to 2 nmol/L docetaxel, or 50 ng/mL doxorubicin resulted in significantly greater inhibition of cell growth and induction of apoptosis compared with either agent alone. Moreover, we found that the NF-kappaB activity was significantly increased within 2 hours of cisplatin and docetaxel treatment and that the NF-kappaB inducing activity of these agents was completely abrogated in cells pretreated with genistein. These results were also supported, for the first time, by animal experiments, p65 cDNA transfection and p65 small interfering RNA studies, which clearly showed that a specific target (NF-kappaB) was affected in vivo. Collectively, our results clearly suggest that genistein pretreatment inactivates NF-kappaB and may contribute to increased growth inhibition and apoptosis induced by cisplatin, docetaxel, and doxorubicin in prostate, breast, lung, and pancreatic cancer cells. Theses results warrant carefully designed clinical studies investigating the combination of soy isoflavones and commonly used chemotherapeutic agents for the treatment of human cancers.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

Sequence dependent potentiation of gemcitabine by flavopiridol in human breast cancer cells.

PURPOSE: Flavopiridol is a novel cyclin dependent kinase (cdk) inhibitor currently in Phase I and II clinical trials. We investigated the interaction between flavopiridol and gemcitabine in two human breast cancer cell lines. Experimental design. MCF-7 [Estrogen receptor (ER) positive] and MDA-MB-231 cells (ER negative) were treated with sub-cytotoxic concentrations of gemcitabine (G), flavopiridol (F), and flavopiridol followed by gemcitabine (F-G), or gemcitabine followed by flavopiridol (G-F) and assayed for biological activity. RESULTS: Growth inhibition assessed by serial cell counting and MTT assay was highest in the G-F group. Significant increase in apoptosis assessed by flow cytometry, poly-ADP-ribose polymerase (PARP) and Caspase-3 degradation was also highest in the G-F group. Expression of pro-apoptotic Bax was up-regulated and anti-apoptotic Bcl-2 was down-regulated in only the G-F treated cells. Significant up regulation of p21(WAF-1) was demonstrated in the G-F group but not in the reverse regimen treated cells. No effect on protein kinase C (PKC) expression was seen in any of the treated cells. CONCLUSIONS: In conclusion, similar to the results in the gastrointestinal cell lines, a sequence dependent potentiation of the effect of gemcitabine by flavopiridol was demonstrated in breast cancer cell lines and it was independent of ER status. This was accompanied by enhanced apoptosis and the up regulation of p21(WAF-1) protein. These results provide rationale for pre-clinical evaluation of this treatment strategy using animal models and in the design of clinical trials of this drug in combination with cytotoxic therapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2005

A phase II study of celecoxib, gemcitabine, and cisplatin in advanced pancreatic cancer.

BACKGROUND: Pancreatic cancer is amongst the most chemoresistant malignancies. Expression of the cyclooxygenase-2 (COX-2) enzyme plays a major role in tumor progression and resistance to therapy. A Phase II study was undertaken to determine the effect of gemcitabine by fixed-dose rate infusion (FDR), cisplatin and the COX-2 inhibitor, celecoxib, on the 6-month survival rate in patients with metastatic pancreatic cancer. METHODS: The eligibility criteria included a pathologically or cytologically confirmed diagnosis of adenocarcinoma of the pancreas. No prior gemcitabine therapy was allowed. Patients received a combination of gemcitabine 1,000 mg/m(2) over 100 minutes, cisplatin 35 mg/m(2) I.V. on days 1 and 8, and celecoxib continuously at a daily dose of 800 mg. Cycles were repeated every 21 days. RESULTS: Twenty-two patients with metastatic pancreas cancer were enrolled (median age, 59.5 years; M:F, 13:9). The median number of cycles was 2 per patient. The median survival time was 5.8 months (90% CI, 3.6-7.6 months). The probability of survival at 6 months was 46% (90% CI, 27-62%). The major toxicity was neutropenia with grade 3 or 4 toxicities seen in 65% of patients. CONCLUSIONS: The addition of celecoxib to gemcitabine (by FDR) and cisplatin did not appear to increase activity of the chemotherapy doublet in patients with advanced pancreatic cancer. Celecoxib alone may not be sufficient to sensitize pancreatic cancer to the effects of conventional cytotoxic therapy.

Adenocarcinoma↗

PubMed2005

Phase I study of liposomal doxorubicin (Doxil) and cyclophosphamide in solid tumors.

INTRODUCTION: The purpose of this study was to determine the recommended phase II dose (RPTD) of the combination of cyclophosphamide and liposomal doxorubicin (Doxil). PATIENTS AND METHODS: Eligibility criteria included: a diagnosis of non-hematologic cancer with no conventional effective therapy, normal renal, liver and bone marrow function, and ECOG performance status of 0-2. Both drugs were administered intravenously on day 1 of a 21-day cycle. The following doses (mg/m2) of Doxil and cyclophosphamide were tested: 30/500, 40/600, and 48/600. RESULTS: Thirty-seven patients with a median age of 62 years (male:female 21:16) received 119 cycles of Doxil and cyclophosphamide. Hand-foot syndrome and mucositis were the dose limiting toxicities for this combination. Other major toxicities included neutropenia. The side effects to the combination were cumulative. The RPTD of Doxil and cyclophosphamide was 48 mg/m2 and 600 mg/m2, respectively. Three patients with adenocarcinoma of the stomach, fibrosarcoma of the stomach and renal cell carcinoma showed objective antitumor responses. CONCLUSION: The toxicity profile of the combination of Doxil/cyclophosphamide differs significantly from that of non-liposomal doxorubicin plus cyclophosphamide. Major toxicities of the combination include the hand-foot syndrome, stomatitis and neutropenia.

Adult↗

PubMed2005

Experience with docetaxel in the treatment of gastric cancer.

Gastric cancer is the second most common cause of cancer death worldwide. In operable patients, standard care includes surgery with or without adjuvant chemotherapy and radiotherapy; standard care for inoperable disease includes chemotherapy with or without radiotherapy. Docetaxel has shown in vitro and in vivo antitumor effects on human gastric cell lines and gastric cancer xenografts. Phase I through III trials of docetaxel alone and in combination with other chemotherapy agents have subsequently been conducted. This review provides an overview of these studies and suggestions for future directions in the treatment of gastric cancer.

Antineoplastic Agents, Phytogenic↗

PubMed2005

A phase II study of carboplatin and paclitaxel in adenocarcinoma of unknown primary.

BACKGROUND: Cisplatin-based combination chemotherapy is commonly used in the treatment of carcinoma of unknown primary site. Paclitaxel has shown promising activity as a single agent in a number of malignancies. This study was conducted to evaluate the efficacy and toxicity of combination carboplatin and paclitaxel in patients with adenocarcinoma of unknown primary site (ACUP). METHODS: Twenty-two patients with ACUP were enrolled in the study. Patients were treated with 200 mg/m2 paclitaxel intravenously (IV) over 3 hours followed by carboplatin IV with a targeted plasma area under the curve (AUC) of 5 mg/h/mL. RESULTS: A total of 73 treatment courses were administered with a median of 5 courses per patient. Five of the 22 registered patients had a major response for an objective response rate of 23% (90% confidence interval [CI], 0.11-0.40) by intention-to-treat analysis. The median response duration was 4.1 months (90% CI, 3.6-7.1). The median survival time was 6.5 months (90% CI, 5.5-10.1) and the 1-year survival rate was 27% (90% CI, 0.11-0.42). The major toxicity observed was neutropenia, with grade 3-4 neutropenia occurring in 3 patients (14%). There were no treatment-related deaths. CONCLUSIONS: The combination of carboplatin and paclitaxel is a tolerable and moderately active regimen in ACUP.

Adenocarcinoma↗

PubMed2005

Simultaneous targeting of the epidermal growth factor receptor and cyclooxygenase-2 pathways for pancreatic cancer therapy.

The aims of this study were to determine the effects of (a) combining the epidermal growth factor receptor (EGFR) blocker (erlotinib) and the cyclooxygenase-2 inhibitor (celecoxib) on cell growth and apoptosis in human pancreatic cancer cell lines, (b) baseline EGFR expression on the potentiation of erlotinib-induced apoptosis by celecoxib, and (c) the effects of the combination on the expression of the COX-2, EGFR, HER-2/neu, and nuclear factor-kappaB (NF-kappaB). Baseline expression of EGFR was determined by Western blot analysis in five human pancreatic cancer cell lines. BxPC-3, PANC-1, and HPAC had high EGFR and MIAPaCa had low EGFR. Cells were grown in culture and treated with erlotinib (1 and 10 micromol/L), celecoxib (1 and 10 micromol/L), and the combination. Growth inhibition was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and apoptosis was assayed by ELISA. Reverse transcriptase-PCR was used to evaluate COX-2 and EGFR mRNA. EGFR, COX-2, and HER-2/neu expression was determined by Western immunoblotting. Electrophoretic mobility shift assay was used to evaluate NF-kappaB activation. Growth inhibition and apoptosis were significantly (P < 0.05) higher in BxPC-3, HPAC, and PANC-1 cells treated with celecoxib and erlotinib than cells treated with either celecoxib or erlotinib. However, no potentiation in growth inhibition or apoptosis was observed in the MIAPaCa cell line with low expression of the EGFR. Significant down-regulation of COX-2 and EGFR expression was observed in the BxPC-3 and HPAC cells treated with the combination of erlotinib (1 micromol/L) and celecoxib (10 micromol/L) compared with celecoxib- or erlotinib-treated cells. Celecoxib significantly down-regulated HER-2/neu expression in BxPC-3 and HPAC cell lines. Significant inhibition of NF-kappaB activation was observed in BxPC-3 and HPAC cell lines treated with erlotinib and celecoxib. (a) Celecoxib can potentiate erlotinib-induced growth inhibition and apoptosis in pancreatic cell lines, (b) high baseline EGFR expression is a predictor of this potentiation, and (c) the down-regulation of EGFR, COX-2, and HER-2/neu expression and NF-kappaB inactivation contributes to the potentiation of erlotinib by celecoxib.

Apoptosis↗

PubMed2004

Cytochrome p450 and glutathione transferase expression in squamous cell cancer.

PURPOSE: The cytochrome P-450 (CYP) and glutathione S-transferase (GST) enzyme systems modulate the carcinogenic effects of tobacco. Therefore, the expression of these enzymes may be in part responsible for the observed interindividual and inter-racial differences in the risk of development of squamous cell carcinoma of the head and neck (SCCHN). The first aim of this study was to evaluate the feasibility of measuring the expression of the CYP and GST in target tissue from the head and neck. The second aim was to compare the expression of CYPs 1A1, 2E1, and 3A4 in squamous epithelium from African-American and Caucasian pediatric patients. The third aim was to compare the expression of CYPs 1A1, 2E1, 3A4, and GST-pi on the p16 expression in patients with SCCHN. EXPERIMENTAL DESIGN: The expression of CYP 1A1, 2E1, 3A4, GST-pi, and p16 was quantified by immunoblotting. Expression of CYPs 1A1, 2E1, and 3A4 was quantified in tissue from 160 pediatric patients undergoing tonsillectomy. Expression of CYPs 1A1, 2E1, 3A4, GST-pi, and p16 was determined in 46 resected SCCHN patients. RESULTS: Large interindividual variability in the expression of these enzymes was observed in the pediatric and adult populations. No significant difference was observed in CYP 1A1, 2E1, and 3A4 expression of Caucasian and African-American patients. There was no correlation between p16 and enzyme expression in patients with SCCHN. CONCLUSION: Evaluation of CYP expression in the target tissue of interest is feasible. The clinical significance of CYPs and GST-pi alterations in the risk of developing SCCHN will need to be investigated in larger trials.

Blotting, Western↗

PubMed2004

Intensity-modulated radiotherapy (IMRT) and concurrent capecitabine for pancreatic cancer.

PURPOSE: Local failure continues to be a major problem in the management of pancreatic cancer. Delivery of adequate radiation doses to the pancreas is limited by radiation-sensitive normal structures in the upper abdomen. To overcome some of these restrictions, we have developed a regimen of intensity-modulated radiotherapy (IMRT) with concurrent capecitabine. METHODS AND MATERIAL: This is a retrospective analysis of the first 15 patients with adenocarcinoma of the pancreas treated on this regimen (7 as adjuvant therapy after curative resection and 8 patients for unresectable disease). Intensity-modulated radiotherapy was planned using the CORVUS system and delivered with a segmented multileaf collimator, using a 6-MV photon beam and 10 intensity steps. Two target volumes were entered: target 1 consisted of the gross tumor volume (in unresectable cases) or the tumor bed (in postsurgical cases); and target 2 consisted of the draining lymph nodes. Both targets were treated simultaneously in 25 daily fractions, 5 days a week. In the postoperative setting, the total dose to target 1 was 45-54 Gy (median, 54 Gy). For unresectable disease the dose was 54-55 Gy (median, 54 Gy). The total dose to target 2 was 45 Gy in all patients. Patients were treated with one of two six-field beam arrangements found to produce superior dose distributions. Capecitabine was given at 1,600 mg/m(2)/day in two divided doses, 5 days per week, concurrently with radiotherapy. In addition, most patients (73%) received gemcitabine-based chemotherapy. Systemic chemotherapy was given before, after, or both before and after chemoradiotherapy in 47%, 7%, and 20% of patients, respectively. Patients were evaluated on a weekly basis. RESULTS: Treatment was tolerated well. Grade 1/2 nausea/vomiting developed in 8 patients (53%) and Grade 1/2 hematologic toxicity developed in 9 patients (60%). Only 1 patient (7%) had Grade 3 toxicity, a gastric ulceration that responded to medical management. Nine patients (60%) had weight loss (median, 7 lbs; range, 3-12 lbs). The median follow-up time is 8.5 months (10.1 months in patients who are alive). In the resectable group there have been no deaths, and there has been 1 local relapse (14%). In the unresectable group there have been 2 deaths, and the 1-year actuarial survival rate is 69%. Two patients converted to resectability, 5 patients (62.5%) have persistent locoregional disease after chemoradiotherapy, and 1 patient (12%) is locally controlled without surgery. CONCLUSIONS: This regimen of IMRT with tumor-selective radiosensitization is well tolerated. The low toxicity profile compares favorably with that of protocols based on continuous-infusion 5-fluorouracil or gemcitabine, and the preliminary indications of efficacy are encouraging.

Adenocarcinoma↗