TIDIER Trial: A Randomized, Phase II Clinical Trial of Time-Restricted Eating Versus Dietary Counseling to Improve the Effect of Radiotherapy.
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Journal Article↗
Biomedical subjects
Paul Frankel
Publications and source records attributed to Paul Frankel.
A phase I study of oxaliplatin in combination with gemcitabine: correlation of clinical outcome with gene expression.
PURPOSE: Oxaliplatin has in vitro activity similar to or higher than other platinum agents. Preclinically, gemcitabine has demonstrated synergy when combined with platinum compounds. These facts formed the rationale for determining the maximum tolerated dose (MTD) of gemcitabine in combination with oxaliplatin. METHODS: Eligible patients with advanced incurable solid tumors were given oxaliplatin 130 mg/m2 as a 2-h infusion on day 1 followed by escalating doses of gemcitabine given over 30 min on day 1 and 8 of a 21-day cycle. RESULTS: A total of 43 patients were enrolled, including 30 patients at the MTD in an expanded cohort. At a gemcitabine dose of 800 mg/m2, 1/6 patients had a dose limiting toxicity (DLT) (grade 3 blurred vision and memory loss). At 1,000 mg/m2, 1/6 patients had a DLT (grade 3 increase in AST). At 1,200 mg/m2, 2/3 patients had a DLT (grade 4 thrombocytopenia and grade 3 confusion). The MTD of gemcitabine with 130 mg/m2 of oxaliplatin was therefore 1,000 mg/m2. The clearances of gemcitabine and ultrafilterable platinum are within the ranges previously reported for single agents. A patient with colon cancer had a partial response, and 21 patients had a best response of stable disease. In patients with tumor biopsies treated at the MTD, decreased ribonucleotide reductase M2 expression correlated with response. CONCLUSION: Treatment with gemcitabine and oxaliplatin was well tolerated with primarily hematologic toxicity at the MTD. Study of biochemical correlates of response remain of interest thought current results remain exploratory.
Adult↗
Salvage high-dose-rate (HDR) brachytherapy for recurrent head-and-neck cancer.
BACKGROUND: A significant portion of head-and-neck cancer patients will develop persistent or recurrent disease after definitive treatment. Radiation therapy is often used as definitive therapy or as an adjunct to surgery. Recurrent cancer of the head and neck in the previously irradiated field is, thus, a common occurrence and poses a therapeutic challenge. Some studies have evaluated low-dose-rate (LDR) brachytherapy as a therapeutic option, including a large case series with long-term follow-up by our own institution. High-dose-rate (HDR) brachytherapy offers therapeutic advantages over LDR brachytherapy. This study evaluates the local control and outcomes of patients with previously irradiated recurrent head-and-neck cancer treated with HDR interstitial brachytherapy. METHODS AND MATERIALS: Between 1997 and 2002, 30 patients who received prior radiation therapy for primary tumors of the head and neck were treated for biopsy-proven recurrent disease. All patients received previous radiation as definitive therapy alone or as adjunct to surgery. All patients were inoperable, refused surgery, or had gross residual disease after salvage surgery for their recurrent disease. Thirty-six sites on the 30 patients were implanted by application of high-dose-rate interstitial brachytherapy techniques with mean tumor dose of 34 Gy (18-48 Gy) in twice daily fractions of 300 to 400 cGy per fraction. RESULTS: At a minimum follow-up of 12 months, local tumor control was achieved in 69% of implanted sites. Disease-specific survival at 1 and 2 years was 54% and 45%, respectively. Overall survival at 1 and 2 years was 56% and 37%, respectively. Grade 3/4 late complications occurred in 16% of the patients. No fatal complications occurred. CONCLUSION: HDR brachytherapy can play an important role in the salvage treatment of previously irradiated recurrent head-and-neck cancer. This study shows that comparable results are obtained by HDR brachytherapy with fewer late complications than were indicated by previously reported data for LDR brachytherapy.
Adenocarcinoma↗
The cyclin-dependent kinase inhibitor UCN-01 plus cisplatin in advanced solid tumors: a California cancer consortium phase I pharmacokinetic and molecular correlative trial.
BACKGROUND: UCN-01 (7-hydroxy-staurosporine) is a novel antineoplastic agent targeting cyclin-dependent kinases, which shows potent in vitro and in vivo activity against a broad range of tumor types. Our group has previously shown that UCN-01 potentiates the apoptotic response of agents such as cisplatin in vitro by preventing sequence-specific abrogation of G2 arrest caused by DNA-damaging chemotherapies. PATIENTS AND METHODS: This National Cancer Institute-sponsored phase I trial was designed to determine the safety, maximum tolerated dose, and pharmacokinetics of escalating doses of cisplatin in combination with UCN-01 in patients with advanced malignant solid tumors, as well as to do molecular correlative studies on tumor specimens. Cisplatin was infused over 1 hour before UCN-01 (45 mg/m2/d) given as a 72-hour continuous infusion. Escalation of cisplatin was planned through five dose levels at 20, 30, 45, 60, and 75 mg/m2. RESULTS: Ten patients were accrued. Accrual was halted at dose level 2 (cisplatin, 30 mg/m2) due to dose-limiting toxicities consisting of grade 5 sepsis with respiratory failure associated with grade 3 creatinine (one patient) and grade 3 atrial fibrillation (one patient). Plasma and salivary pharmacokinetics of UCN-01 were unaffected by cisplatin. Pretreatment and posttreatment tumor biopsies showed that UCN-01 was active against a key molecular target, the checkpoint kinase Chk1. CONCLUSIONS: This phase I trial failed to achieve targeted therapeutic dose levels of cisplatin when combined with prolonged infusion UCN-01. However, because preclinical data indicate that UCN-01 potentiates response to platinum, further studies with alternative dose schedules of the combination, or with other platinum analogues, are warranted.
Antineoplastic Combined Chemotherapy Protocols↗
Paclitaxel-based high-dose chemotherapy with autologous stem cell rescue for relapsed germ cell cancer.
We evaluated the antitumor activity of tandem cycles of high-dose chemotherapy with autologous peripheral stem cell transplantation (aPSCT) in relapsed germ cell tumors by using high-dose paclitaxel, carboplatin, etoposide, and ifosfamide. Thirty-three patients were entered, and 31 underwent protocol therapy. Paclitaxel 350 mg/m2 (5 patients) or 425 mg/m2 (26 patients) by 24-hour continuous intravenous infusion was followed by 3 daily doses of carboplatin and either etoposide (cycle 1) or ifosfamide/mesna (cycle 2). The carboplatin dose had a calculated area under the curve of 7 mg-min/mL, and the daily dose of etoposide was 20 mg/kg (cycle 1). Ifosfamide 3 g/m2/d for 3 days (with mesna uroprotection) was substituted for etoposide in cycle 2. Each cycle was supported by granulocyte colony-stimulating factor-mobilized peripheral blood stem cells. Thirty-one patients were evaluable for response, toxicity, and long-term disease control. Two patients did not undergo aPSCT because of rapid disease progression. Nineteen patients received both cycles of aPSCT, 8 progressed after cycle 1, 3 refused the second cycle, and 1 died of fungal infection during cycle 1. Twelve patients remain relapse free at a median of 67 months from the initiation of therapy. Whereas the International Germ Cell Cancer Collaborative Group category at the time of initial diagnosis did not seem to predict outcome, the patient's probability of achieving durable remission was significantly associated with the Beyer prognostic score at the time of protocol entry. Regimens containing the most active agents in relapsed nonseminomatous germ cell tumors, including high-dose paclitaxel, are well tolerated and have promising activity even in patients with poor-risk features who do not achieve durable remissions with standard therapy. The Beyer prognostic system is a valuable predictor for patients undergoing aPSCT.
Adolescent↗
Intermittent dosing of the farnesyl transferase inhibitor tipifarnib (R115777) in advanced malignant solid tumors: a phase I California Cancer Consortium Trial.
Tipifarnib (R115777) inhibits farnesylation of key proteins that modulate signaling pathways implicated in cell growth and proliferation, including members of the Ras and Rho families. It has broad-spectrum antiproliferative activity in vitro and in vivo. Clinical trials employing a continuous administration schedule have demonstrated dose-limiting neurotoxicity and myelosuppression. Preclinical studies have shown that intermittent oral administration can suppress tumor growth comparable to continuous administration. We conducted a National Cancer Institute-sponsored phase I trial to determine the feasibility of an intermittent dosing schedule of R115777 given orally twice daily on weeks 1 and 3 of a 28-day cycle in patients with malignant solid tumors. Starting dose was 300 mg twice daily (b.i.d.) with escalation by 300 mg b.i.d. increments over six dose levels to a maximum of 1800 mg b.i.d. Dose-limiting toxicity (DLT) was defined as any grade 3 or 4 non-hematologic toxicity, grade 4 thrombocytopenia, grade 4 neutropenia (ANC) with fever (38.3 degrees C or above) or a documented infection. Twenty-one patients with advanced solid tumors, all of whom had prior systemic therapy, were accrued. Grade 3 fatigue was dose limiting for two of three patients at the 900 mg b.i.d. dose level. Although no responses were seen, four of six patients with stable disease remained on study for at least a year (16, 17, 13 and 12 months) before developing progressive disease. Three of these prolonged stable disease patients had non-small cell lung cancer. We conclude that intermittent dosing of R115777 is feasible and tolerable. The recommended phase II dose is 600 mg orally b.i.d. on alternate weeks.
Administration, Oral↗
Clinicopathologic significance of synchronous and metachronous adenomas in colorectal cancer.
PURPOSE: Colorectal cancers (CRCs) evolve from a multiple-step tumorigenesis and, morphologically, are characterized by adenoma. Colorectal cancers with adenomas have distinct clinical features, including reports of improved survival. It is hypothesized that this survival advantage is related to biologic differences in CRC with adenomas rather than earlier diagnosis or earlier stage of disease presentation. PATIENTS AND METHODS: A retrospective chart review of 569 patients treated from 1983 through 2002 was conducted. Data on age, sex, and survival; CRC stage, location, and recurrence; adenoma number, size, histology, and location; and colonoscopy history were analyzed. RESULTS: The mean patient age was 62 years (range, 17-90 years), and 54% of patients were men. The majority of CRCs were left-sided (67%). The American Joint Committee on Cancer stage distribution was 0/I (12%), II (21%), III (34%), and IV (33%). Colorectal cancer with synchronous adenoma was seen in 33% of cases; overall, CRC with adenoma comprised 42% of cases. The event-free survival and overall survival favored CRC with adenoma. After adjusting for age, disease stage, sex, and total number of colonoscopic examinations, the relative risk for an event was 1.51 (P < 0.003) for patients without adenomas versus those with adenomas. CONCLUSION: Colorectal cancer with adenoma represents a distinct population of patients with CRC. The apparent association seems to confer a survival advantage that is not based on age, sex, or disease stage. The survival benefit, although slightly less dramatic, remained significant even when controlled for the number of colonoscopies.
Adenoma↗
RalA interacts with ZONAB in a cell density-dependent manner and regulates its transcriptional activity.
Ral proteins are members of the Ras superfamily of small GTPases and are involved in signalling pathways for actin cytoskeleton remodelling, cell cycle control, cellular transformation and vesicle transport. To identify novel RalA effector proteins, we used the reverse Ras recruitment system and found that RalA interacts with a Y-box transcription factor, ZO-1-associated nucleic acid-binding protein (ZONAB), in a GTP-dependent manner. The amount of the RalA-ZONAB complex increases as epithelial cells become more dense and increase cell contacts. The RalA-ZONAB interaction results in a relief of transcriptional repression of a ZONAB-regulated promoter. Additionally, expression of oncogenic Ras alleviates transcriptional repression by ZONAB in a RalA-dependent manner. The data presented here implicate the RalA/ZONAB interaction in the regulation of ZONAB function.
Animals↗
Feasibility and pharmacokinetic study of infusional dexrazoxane and dose-intensive doxorubicin administered concurrently over 96 h for the treatment of advanced malignancies.
PURPOSE: Dexrazoxane administration prior to short infusion doxorubicin prevents anthracycline-related heart damage. Since delivery of doxorubicin by 96-h continuous intravenous infusion also reduces cardiac injury, we studied delivering dexrazoxane and doxorubicin concomitantly by prolonged intravenous infusion. METHODS: Patients with advanced malignancies received tandem cycles of concurrent 96-h infusions of dexrazoxane 500 mg/m2 and doxorubicin 165 mg/m2, and 24 h after completion of chemotherapy, granulocyte-colony stimulating factor (5 microg/kg) and oral levofloxacin (500 mg) were administered daily until the white blood cell count reached 10,000 microl(-1). Plasma samples were analyzed for dexrazoxane and doxorubicin concentrations. RESULTS: Ten patients were enrolled; eight patients had measurable disease. Two partial responses were observed in patients with soft-tissue sarcoma. The median number of days of granulocytopenia (<500 microl(-1)) was nine and of platelet count <20,000 microl(-1) was seven. Six patients received a single cycle because of progression (one), stable disease (four), or reversible, asymptomatic 10% decrease in cardiac ejection fraction (two). Principal grade 3/4 toxicities included hypotension (two), anorexia (four), stomatitis (four), typhlitis (two), and febrile neutropenia (seven), with documented infection (three). One death from neutropenic sepsis occurred. Dexrazoxane levels ranged from 1270 to 2800 nM, and doxorubicin levels ranged from 59.1 to 106.9 nM. CONCLUSIONS: These results suggest that tandem cycles of concurrent 96-h infusions of dexrazoxane and high-dose doxorubicin can be administered with minimal cardiac toxicity, and have activity in patients with recurrent sarcomas. However, significant non-cardiac toxicities indicate that the cardiac sparing potential of this approach would be maximized at lower dose levels of doxorubicin.
Adult↗
Prognostic indicators and survival in patients with stage IIIB inflammatory breast carcinoma after dose-intense chemotherapy.
PURPOSE: To improve treatment outcome for patients presenting with inflammatory breast cancer (IBC), we have sequentially developed and tested single and tandem dose-intense chemotherapy regimens (DICT). Tumor- and treatment-related factors were analyzed to generate a prognostic model. PATIENTS AND METHODS: Between May 1989 and April 2002, 120 patients received conventional-dose chemotherapy, surgery, and sequentially developed single- or tandem-cycle DICT. Disease- and treatment-specific features were subjected to univariate and multivariate analysis to correlate with outcome. RESULTS: At a median follow-up of 61 months (range, 21 to 161 months), estimated 5-year relapse-free survival (RFS) and overall survival (OS) were 44% (95% CI, 34% to 53%) and 64% (95% CI, 55% to 73%), respectively. In an age-adjusted multivariate analysis, RFS was better in patients with estrogen receptor (ER)/progesterone receptor (PR)-positive tumors (P =.002), for patients with fewer than four involved axillary nodes before DICT (P =.01), and in patients treated with radiation therapy (P =.001) and tandem DICT (P =.049). OS was improved in patients with ER/PR-positive tumors (P =.002), in those with fewer than four involved axillary nodes before DICT (P =.03), and in patients treated with radiation therapy (P =.002). CONCLUSION: This retrospective analysis suggests that either single or tandem DICT can be administered safely and may benefit selected patients with stage IIIB IBC. Those with receptor-negative IBC and with four or more involved axillary nodes before DICT need improved neoadjuvant and postadjuvant intensification therapy. A prospective randomized trial of single versus tandem DICT would be required to confirm the potential benefit of tandem DICT in the setting of IBC.
Adult↗
Gemcitabine in patients with non-small-cell lung cancer previously treated with platinum-based chemotherapy: a phase II California cancer consortium trial.
A phase II trial was designed to evaluate the efficacy and toxicity of gemcitabine in patients with non-small-cell lung cancer (NSCLC) previously treated with platinum-containing regimens and prospectively categorized for platinum response status. Treatment consisted of gemcitabine 1000 mg/m2 given intravenously on days 1 and 8 of a 21-day cycle. The status of p53 in pretreatment tumor tissue was assessed by immunohistochemistry (IHC). Sixty-one patients who progressed or recurred following platinum-based therapy were enrolled, 26 platinum-sensitive and 35 platinum-refractory. A median of 4 treatment courses (range, 2-7 courses) was delivered. Of the 55 patients assessable for response, there was 1 confirmed complete response and 3 with a confirmed partial response for an overall response proportion of 7%. Twenty-one patients had stable disease while 28 progressed and 2 patients had an unconfirmed partial response. Three of the responders (2 confirmed, 1 unconfirmed) were platinum-refractory. Median progression-free survival (PFS) and overall survival for all patients were 4.1 months and 8.6 months, respectively. Median PFS and overall survival for the platinum-sensitive and platinum-refractory cohorts were 5.4 months versus 3.1 months, and 11.9 months versus 7.1 months, respectively. Toxicity was principally hematologic with grade 3/4 neutropenia in 21% and grade 4 platelets in 8%. There were no treatment-related deaths. Twenty-four of 33 patients (73%) had p53-positive tumors. Although no significant association between platinum sensitivity and p53 status was seen, patients with platinum-sensitive disease and negative p53 by IHC had a trend toward longer survival compared to those with platinum-refractory disease and/or p53 positivity (P = 0.06). We concluded that salvage gemcitabine in this dose and schedule is safe and tolerable in previously platinum-treated patients with NSCLC.
Adult↗
Phase I trial of intraperitoneal docetaxel in the treatment of advanced malignancies primarily confined to the peritoneal cavity: dose-limiting toxicity and pharmacokinetics.
PURPOSE: The purpose of this Phase I study was to determine the maximum tolerated dose and dose-limiting toxicities (DLTs) of i.p. docetaxel and to determine the peritoneal pharmacokinetics and pharmacological advantage of this agent. EXPERIMENTAL DESIGN: Twenty-one patients with peritoneal carcinomatosis received docetaxel administered via an implanted i.p. catheter at doses of 40, 80, 100, 125, or 156 mg/m2 every 3 weeks. DLTs on course 1 were used to define the maximum tolerated dose. RESULTS: Tumor types included gastric adenocarcinoma (n=7), ovarian cancer (n=4), other gastrointestinal primaries (n=3), and other cancers (n=7). Sixty cycles of i.p. docetaxel (median, 2; range, 1-11) were delivered. DLTs occurred in two patients at the 156 mg/m2 dose level; both developed an ileus, and one patient died of neutropenic sepsis. One of five evaluable patients treated with 125 mg/m2 docetaxel i.p. developed grade 4 neutropenic sepsis and stomatitis; another patient developed renal failure attributable to glomerulonephritis and grade 3 thrombocytopenia that was not judged to be dose-limiting. One of six patients receiving 100 mg/m2 D, the recommended Phase II dose, developed grade 4 neutropenia lasting <5 days. Other non-DLT treatment-related toxicities included dehydration requiring i.v. fluids, emesis, stomatitis, constipation, and abdominal pain. Best response on protocol therapy included 7 of 18 patients with stable disease for a median of 5 cycles (range, 2-11); 11 patients progressed by the first evaluation after a median of 2 cycles (range, 1-3). There were three patients inevaluable for response who received only one cycle of i.p. docetaxel (two because of patient preference and one because of adhesion formation). Pharmacokinetic evaluation revealed mean plasma areas under the curves (AUC) at 100 and 125 mg/m2 i.p. docetaxel of 3.14 and 6.33 microM.h (ranges, 1.02-5.88 and 3.97-12.70 microM. h), respectively; the mean peritoneal AUCs were 315 and 1063 microM.h (ranges, 250-373 and 239-2222 microM.h), respectively. The mean peak plasma concentrations at 100 and 125 mg/m2 i.p. docetaxel were 0.46 and 0.66 microM, and the mean peak peritoneal concentrations at those doses were 59 and 81 microM, respectively. The median and mean pharmacological advantage calculations (AUCperitoneal/AUCplasma) across all dose levels were 152 and 181, respectively (range, 18.8-367.4). The mean peritoneal 24- and 96-h concentrations were 0.9 microM (range, 0.2-1.6 microM) and <0.1 nM, respectively. The mean time that the concentration was >0.1 microM was 31.2 h (range, 27-36.5 h). CONCLUSIONS: i.p. docetaxel can be safely delivered at a dose of 100 mg/m2 i.p. every 3 weeks. This route of administration provides a significant peritoneal pharmacological advantage while delivering systemic concentrations consistent with the administration of standard i.v. doses.
Adenocarcinoma↗
SU5416 plus interferon alpha in advanced renal cell carcinoma: a phase II California Cancer Consortium Study with biological and imaging correlates of angiogenesis inhibition.
PURPOSE: Vascular endothelial growth factor (VEGF) is expressed in up to 70% of renal cell carcinomas (RCCs) and is a rational therapeutic target. SU5416 is a small molecule inhibitor of VEGF-mediated signaling through Flk-1, a transmembrane tyrosine kinase. IFN-alpha also possesses dose- and schedule-dependent antiangiogenic effects at doses lower than those used for RCC therapy. We hypothesized that SU5416 plus low dose IFN-alpha 2B (Intron-A) would result in a 1-year event-free survival (EFS), exceeding 20% in patients with metastatic RCC using the results of a randomized immunotherapy trial as historical control. Efficacy was correlated with serial plasma VEGF and plasminogen activator inhibitor-1 levels and with positron emission tomography scans. EXPERIMENTAL DESIGN: Thirty patients were treated with SU5416 145 mg/m(2) i.v. twice weekly plus Intron-A 1 million units s.c. twice daily, cycled every 6 weeks. RESULTS: Fifteen patients (50%) had stable disease (SD) at 12 weeks, including 1 minor response and 8 with progressive disease (27%). Median survival time was 10 months, and 1-year EFS was 6% (95% confidence interval, 1-35). The most common grade 3 or 4 toxicities included fatigue and lymphopenia, among others. There were 3 on-study deaths, 2 of which were infection-related. Significant declines in median plasma levels of VEGF pre- and posttherapy were observed. In 5 patients with paired FDG and O-15 positron emission tomography scans, tumor metabolism and perfusion were unchanged in 3 patients with SD, increased in 1 patient with progression, and decreased in 1 patient with SD. CONCLUSIONS: Although SU5146 plus low-dose IFN exhibits biological activity in RCC as evidenced by significant declines in serial VEGF and plasminogen activator inhibitor-1 plasma levels, the 1-year EFS of 6% and adverse toxicity profile diminishes enthusiasm for additional studies with this combination in advanced RCC.
Adult↗
Tirapazamine plus carboplatin and paclitaxel in advanced malignant solid tumors: a california cancer consortium phase I and molecular correlative study.
PURPOSE: Tumor hypoxia confers chemotherapy resistance. Tirapazamine is a cytotoxin that selectively targets hypoxic cells and has supra-additive toxicity with platinums and taxanes in preclinical studies. We conducted a Phase I study of tirapazamine, carboplatin, and paclitaxel and assessed potential plasma markers of hypoxia as surrogates for response. EXPERIMENTAL DESIGN: Forty-two patients with advanced solid tumors were treated at four dose levels; parallel dose escalations were carried out in chemotherapy-naive and previously treated subjects. Pre and post-therapy plasma levels of the hypoxia-induced proteins plasminogen activator inhibitor-1 and vascular endothelial growth factor were measured. RESULTS: Three of four chemotherapy-naïve patients developed dose-limiting toxicities at dose level 4 (grade 3 stomatitis/infection, grade 3 emesis, and grade 4 febrile neutropenia). Four of seven previously treated patients developed dose-limiting toxicities at dose level 3, including one death [grade 3 myalgia, grade 3 infection/grade 4 neutropenia, grade 3 infection/grade 4 neutropenia, and grade 5 infection (death)/grade 4 neutropenia]. Of 38 patients assessable for response, 3 had a complete response, 1 a partial response, 1 an unconfirmed partial response, and 23 had stable disease in at least one evaluation; 10 quickly progressed. One complete responder had normalization of vascular endothelial growth factor and plasminogen activator inhibitor-1 levels. CONCLUSION: Dose levels 3 (carboplatin AUC of 6, 225 mg/m(2) paclitaxel, and 330 mg/m(2) tirapazamine) and 2 (carboplatin AUC 6, 225 mg/m(2) paclitaxel, and 260 mg/m(2) tirapazamine) are the maximum tolerated doses for chemotherapy naive and patients treated previously, respectively. Dose level 3 is the experimental arm of a Phase III Southwest Oncology Group trial (S0003) in advanced non-small cell lung cancer. Potential markers of tumor hypoxia may be useful correlates in studies of hypoxic cytotoxins and are being prospectively investigated in S0003.
Adult↗
Quantification of chemotherapeutic target gene mRNA expression in human breast cancer biopsies: comparison of real-time reverse transcription-PCR vs. relative quantification reverse transcription-PCR utilizing DNA sequencer analysis of PCR products.
The solid tumor mRNA expression of genes related to the mechanism of action of certain antineoplastic agents is often predictive of clinical efficacy. We report here on the development of a rapid and practical real-time RT-PCR method to quantify genetic expression in solid tumors. The genes examined are related to the intracellular pharmacology of gemcitabine and cisplatin, two drugs that are used in the treatment of several types of advanced cancer. We evaluated target gene mRNA levels from breast tumor samples using two quantitative RT-PCR methods: 1) an improved relative RT-PCR method using fluorescence-labeled primers, automated PCR set up, and GeneScan analysis software; and 2) real-time RT-PCR with redesigned primers using an ABI 7900HT instrument, with additional postprocessing of the data to adjust for efficiency differences across the target genes. Using these methods, we quantified mRNA expression levels of deoxycytidine kinase (dCK), deoxycytidylate deaminase (dCDA), the M1 and M2 subunits of ribonucleotide reductase (RRM1, RRM2), and excision cross complementation group 1 (ERCC1) in 35 human "fresh" frozen breast cancer biopsies. While both assay methods were substantially more rapid than traditional RT-PCR, real-time RT-PCR appeared to be superior to the amplification end-point measurement in terms of precision and high throughput, even when a DNA sequencer was used to assess fluorescence-labeled PCR products. This reproducible, highly sensitive real-time RT-PCR method for the detection and quantification of the mRNAs for dCK, dCDA, RRM1, RRM2, and ERCC1 in human breast cancer biopsies appears to be more informative and less time-consuming than either classical radioisotope-dependent RT-PCR or the technique utilizing GeneScan analysis described herein. By allowing the measurement of intratumoral target gene expression, these new methods may prove useful in predicting the clinical utility of gemcitabine- and platinum-containing chemotherapy programs in patients with solid tumors.
Algorithms↗
Down-regulation of growth arrest DNA damage-inducible gene 45beta expression is associated with human hepatocellular carcinoma.
In this study, we describe the growth arrest DNA damage-inducible gene 45beta (GADD45beta), whose expression was significantly down-regulated in the hepatocellular carcinoma (HCC) microarray study and confirmed by Northern blot analysis. The results suggested that expression of GADD45beta was decreased in human liver cancer cell lines HepG2 and Hep3B, but not in normal human embryonic liver cell line CL-48 or normal liver tissue. Histochemistry study and real-time PCR further confirmed that GADD45beta staining in HCC was significantly decreased when compared to surrounding non-neoplastic liver tissue. In further studies of multiple human cancer tissues, GADD45beta strongly stained tissues such as colon cancer, breast cancer, prostate cancer, squamous cell cancer, lymphoma, and leiomyosarcoma, suggesting that the decreased expression of GADD45beta is specific to HCC. Eighty-five cases of primary HCC were further examined by immunohistochemistry and statistical analyses demonstrated that HCC scored lower than matched non-neoplastic liver tissues consistently and significantly. No staining occurred in 12.94% of HCC cases (score = 0, n = 11); 42.35% had weak staining (score = 1, n = 36); 27.06% had moderate staining (score = 2, n = 23); and 17.65% had staining as strong as normal tissue (score = 3, n = 15). Overall, surrounding non-neoplastic liver tissue was highly positive for GADD45beta compared to adjacent neoplastic liver tissues (P < 0.01). We further observed that down-regulation of GADD45beta expression was strongly correlated with differentiation (P < 0.01) and high nuclear grade (P < 0.01). Moreover, we found that expression of GADD45beta was inversely correlated to the presence of mutant p53 in HCC tissue (P < 0.05). Thus, the results of our study suggest that GADD45beta, which is down-regulated in most cases of HCC, remains an ideal candidate for development as a molecular marker in the diagnosis of HCC and as a potential therapeutic target.
Adult↗
Elevated phospholipase D activity in H-Ras- but not K-Ras-transformed cells by the synergistic action of RalA and ARF6.
Phospholipase D (PLD) activity is elevated in response to the oncogenic stimulus of H-Ras but not K-Ras. H-Ras and K-Ras have been reported to localize to different membrane microdomains, with H-Ras localizing to caveolin-enriched light membrane fractions. We reported previously that PLD activity elevated in response to mitogenic stimulation is restricted to the caveolin-enriched light membrane fractions. PLD activity in H-Ras-transformed cells is dependent upon RalA, and consistent with a lack of elevated PLD activity in K-Ras-transformed cells, RalA was not activated in K-Ras-transformed cells. Although H-Ras-induced PLD activity is dependent upon RalA, an activated mutant of RalA is not sufficient to elevate PLD activity. We reported previously that RalA interacts with PLD activating ADP ribosylation factor (ARF) proteins. In cells transformed by H-Ras, we found increased coprecipitation of ARF6 with RalA. Moreover, ARF6 colocalized with RalA in light membrane fractions. Interestingly, ARF6 protein levels were elevated in H-Ras- but not K-Ras-transformed cells. A dominant-negative mutant of ARF6 inhibited PLD activity in H-Ras-transformed NIH 3T3 cells. Activated mutants of either ARF6 or RalA were not sufficient to elevate PLD activity in NIH 3T3 cells; however, expression of both activated RalA and activated ARF6 in NIH 3T3 cells led to increased PLD activity. These data suggest a model whereby H-Ras stimulates the activation of both RalA and ARF6, which together lead to the elevation of PLD activity.
3T3 Cells↗
Parametric models for accelerated and long-term survival: a comment on proportional hazards.
The Cox proportional hazards model (CPH) is routinely used in clinical trials, but it may encounter serious difficulties with departures from the proportional hazards assumption, even when the departures are not readily detected by commonly used diagnostics. We consider the Gamel-Boag (GB) model, a log-normal model for accelerated failure in which a proportion of subjects are long-term survivors. When the CPH model is fit to simulated data generated from this model, the results can range from gross overstatement of the effect size, to a situation where increasing follow-up may cause a decline in power. We implement a fitting algorithm for the GB model that permits separate covariate effects on the rapidity of early failure and the fraction of long-term survivors. When effects are detected by both the CPH and GB methods, the attribution of the effect to long-term or short-term survival may change the interpretation of the data. We believe these examples motivate more frequent use of parametric survival models in conjunction with the semi-parametric Cox proportional hazards model.
Algorithms↗