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C M Rudin

Publications and source records attributed to C M Rudin.

At least 19 recordsLinked to original sources
PubMed2002

A pilot trial of G3139, a bcl-2 antisense oligonucleotide, and paclitaxel in patients with chemorefractory small-cell lung cancer.

BACKGROUND: Chemorefractory small-cell lung cancer (SCLC) is defined as disease that progresses during primary therapy or within 3 months of completion of primary therapy. Patients with chemorefractory SCLC have a very poor prognosis, and no treatment has been shown to be of significant clinical benefit. Elevated expression of Bcl-2 is found in the majority of SCLCs and has been associated with therapeutic resistance. Suppression of Bcl-2 levels through the use of G3139, an antisense oligonucleotide complementary to the mRNA encoding Bcl-2, might increase the antitumor efficacy of cytotoxic therapy. PATIENTS AND METHODS: Twelve patients with chemorefractory SCLC participated in this pilot trial of paclitaxel combined with G3139. G3139 was given by continuous i.v. infusion over 7 days at a fixed dose of 3 mg/kg/day. Paclitaxel dose was initially 175 mg/m2 on day 6, but was decreased to 150 mg/m2 due to myelosuppression observed in two of the three patients treated in the first dose cohort. RESULTS: The combination of paclitaxel at 150 mg/m2 and G3139 at 3 mg/kg/day was found to be feasible and well tolerated. No objective responses were observed, but two patients had stable disease, one remaining stable on therapy for >30 weeks. Plasma G3139 levels were determined, and were found to be highest in the patient with prolonged stable disease, suggesting that individual variation in metabolism and clearance of the antisense oligonucleotide may influence activity. CONCLUSIONS: This study demonstrates that G3139 can be combined with paclitaxel in a cytotoxic dose range, and suggests that a similar combination be tested for activity in the context of chemoresponsive disease.

Adult↗
PubMed2001

A phase I trial of the oral platinum analogue JM216 with concomitant radiotherapy in advanced malignancies of the chest.

JM216 is an orally administered platinum analogue. We undertook this study to determine the maximally tolerated dose (MTD) of JM216 when administered with concomitant radiotherapy to the chest (200 cGy daily, 5 x/week) in patients with locoregionally advanced non-small cell lung (NSCLC) or esophageal cancer. Patients were excluded for inadequate bone marrow reserve, prior radiotherapy to the primary tumor or previous treatment with platinum drugs. A dose-limiting toxicity (DLT) was defined using the National Cancer Institute (NCI) Common Toxicity Criteria (CTC) and consisted of grade > or = 2 renal, hepatic, cardiac, or pulmonary toxicity or grade > or = 3 hematologic, neurological, or gastrointestinal toxicity. A total of 23 patients were registered; two never received treatment and are excluded from analyses. Six patients were treated at a dose of 30 mg/m2/day for 5 days with two grade 2 DLT's: cough (1 pt) and elevated trans-aminases (1 pt). Seven evaluable patients were treated at 60 mg/m2/day and seven experienced grade 3 or 4 toxicity, five related to myelosuppression. The dose was then reduced to 45 mg/m2/d. Eight patients were evaluable for toxicity, of which 5 experienced DLT: myelosuppression (3 pts), esophagitis (2 pts), dyspnea (1 pt), and elevated creatinine (1 pt). Fourteen patients were evaluable for efficacy, of which 6 had an objective response, including one complete response. The recommended phase II dose of JM216 with concurrent radiation therapy is 30 mg/m2/d for 5 days. The major DLT is myelosuppression with only limited increased toxicity within the field of radiation. This conceivably may limit the use of JM216 as a radiation sensitizer.

Administration, Oral↗
PubMed2001

A phase II trial of 9-aminocaptothecin (9-AC) as a 120-h infusion in patients with non-small cell lung cancer.

In a previous phase II trial of the synthetic topoisomerase I inhibitor, 9-aminocamptothecin (9-AC), given as a 72-h infusion, we identified modest single agent activity of 9% in patients with previously untreated advanced non-small cell lung cancer (NSCLC). Preclinical studies suggested that a more prolonged continuous infusion of the drug might lead to greater antitumor activity. A phase I study recommended a phase II dose of 25 microg/m2/hr for 120 h (3000 microg/m2 over 5 days), administered for 2 consecutive weeks of a 3-week cycle. We utilized this schedule and enrolled 13 chemotherapy-naïve patients with Stage IIIB and IV NSCLC in this trial: median age 67 (range 57-74); 46% male; 92% stage IV; and median performance status 1. Twelve patients are available for response and toxicity evaluation after 2 cycles of therapy. One patient achieved a partial response. Four patients had stable disease while seven patients had progressive disease. Patients with stable or progressive disease after two cycles received no additional 9-AC, and were offered conventional chemotherapy. The median survival time was 10.2 months and the one-year survival rate 28% (95% confidence interval, 5-58%). Significant toxicities included myelosuppression, fatigue, and anorexia. One patient had grade 4 neutropenia following the first week of cycle 2, and did not receive additional therapy. There were no neutropenia-related infections. These data suggest that this prolonged schedule is unlikely to increase 9-AC's very modest activity in NSCLC above that seen with the simpler 72-h administration schedule. Further evaluation of 9-AC in NSCLC is not recommended.

Aged↗
PubMed2001

Transcriptional activation of short interspersed elements by DNA-damaging agents.

Short interspersed elements (SINEs), typified by the human Alu repeat, are RNA polymerase III (pol III)-transcribed sequences that replicate within the genome through an RNA intermediate. Replication of SINEs has been extensive in mammalian evolution: an estimated 5% of the human genome consists of Alu repeats. The mechanisms regulating transcription, reverse transcription, and reinsertion of SINE elements in genomic DNA are poorly understood. Here we report that expression of murine SINE transcripts of both the B1 and B2 classes is strongly upregulated after prolonged exposure to cisplatin, etoposide, or gamma radiation. A similar induction of Alu transcripts in human cells occurs under these conditions. This induction is not due to a general upregulation of pol III activity in either species. Genotoxic treatment of murine cells containing an exogenous human Alu element induced Alu transcription. Concomitant with the increased expression of SINEs, an increase in cellular reverse transcriptase was observed after exposure to these same DNA-damaging agents. These findings suggest that genomic damage may be an important activator of SINEs, and that SINE mobility may contribute to secondary malignancy after exposure to DNA-damaging chemotherapy.

Animals↗
PubMed2001

Phase I Trial of ISIS 5132, an antisense oligonucleotide inhibitor of c-raf-1, administered by 24-hour weekly infusion to patients with advanced cancer.

Raf-1 is a serine/threonine kinase that functions as a critical effector of Ras-mediated signal transduction via the mitogen-activated protein kinase pathway. Constitutive activation of this pathway directly contributes to malignant transformation in many human tumors. A 20-base phosphorothioate oligonucleotide complementary to c-raf-1 mRNA (ISIS 5132; CGP 69846A) has been shown to specifically suppress Raf-1 expression both in vitro and in vivo. This Phase I trial, involving 22 patients with advanced cancer, was designed to evaluate the safety, feasibility, and maximum tolerated dose of ISIS 5132 administration as a weekly 24-h i.v. infusion. Pharmacokinetic analysis was performed, and c-raf-1 mRNA levels in peripheral blood mononuclear cells were assessed using quantitative reverse transcription-PCR. This trial defined a maximum tolerated dose of 24 mg/kg/week on this schedule. Two of four patients treated at 30 mg/kg/week had serious adverse events after the first dose of ISIS 5132, including acute hemolytic anemia and acute renal failure and anasarca. There were no major responses documented. Dose-dependent complement activation was demonstrated on this schedule, but not on previously evaluated schedules, of ISIS 5132 administration. In contrast to other trials of ISIS 5132, there appeared to be no consistent suppression of peripheral blood mononuclear cell c-raf-1 mRNA level on this schedule at any of the dose levels analyzed. These data suggest that the efficacy and toxicity profiles of antisense oligonucleotides may be highly dependent on the schedule of administration and support the analysis of the putative molecular target in the evaluation of novel therapeutics.

Adult↗
PubMed2001

ONYX-015. Onyx Pharmaceuticals.

ONYX-015 (CI-1042), an adenovirus modified selectively to replicate in and kill cells that harbor p53 mutations, is under development by Onyx Pharmaceuticals for the potential treatment of various solid tumors, including head and neck, gastrointestinal and pancreatic tumors. It is a recombinant adenovirus that carries a loss-of-function mutation at the E1B locus, the product of which is a 55 kDa protein that binds to and inactivates the p53 tumor suppressor protein. Wild-type adenoviruses must disable this gene before viral replication can occur. This, the ONYX-015 adenovirus will leave normal cells unaffected. Mutations in the p53 tumor suppressor gene are the most common type of genetic abnormality in cancer, occurring in more than half of all major cancer types. Thus, these cells are susceptible to the virus, which will readily replicate and cause cell death. ONYX-015 is in ongoing phase III trials for the treatment of recurrent head and neck cancer, phase II trials for colorectal, ovary, pancreas and mouth tumors, and phase I trials for digestive disease, esophagus and liver tumors. Onyx Pharmaceuticals was granted US-05677178 covering methods for the treatment of p53-related cancers in October 1997. The patent specifically covers the use of modified adenoviruses and other DNA viruses, which lack viral proteins that bind to p53, for the treatment of cancer patients whose tumors lack p53 function. The USPTO awarded Onyx Pharmaceuticals US-05846945 in December 1998, covering methods for treating cancer using replicating adenoviral therapy in combination with chemotherapy. In April 1999, the company also received EP-094910177.8 covering the technology in Europe.

Adenoviridae↗
PubMed2000

Cell line dependence of Bcl-2-induced alteration of glutathione handling.

Bcl-2 has been associated with both oxidative and antioxidative effects in vivo. Moreover, despite evidence that Bcl-2 is antiapoptotic by virtue of its effect on reactive oxygen species and their scavengers, Bcl-2 exerts its antiapoptotic effects even under anaerobic conditions. The reasons for the variable relationship between Bcl-2 and reactive oxygen species are not clear. The present studies demonstrate that the impact of Bcl-2 on glutathione (GSH) metabolism is cell line-dependent. Bcl-2 overproduction in PC12 cells is associated with increased functional thiol reserves, increased reductive activation of chemotherapeutic prodrugs, and GSH accumulation after treatment with N-acetylcysteine. In contrast, Bcl-2-overproducing MCF-7 breast cancer cells demonstrate neither altered GSH handling nor potentiation of chemotherapeutic prodrug reduction. These findings indicate that the effects of Bcl-2 on GSH handling are millieu-dependent. This could account for the variable effects of Bcl-2 in in vivo systems. Furthermore, since our previous studies have demonstrated that reduction-dependent prodrugs may be useful chemotherapeutic agents against tumors that demonstrate altered GSH handling, screening in vitro for alteration of GSH handling may predict responsiveness of such tumors to these reduction-dependent agents.

Acetylcysteine↗
PubMed1999

Bcl-xL and Bcl-2 expression in squamous cell carcinoma of the head and neck.

BACKGROUND: Inhibition of apoptosis, or programmed cell death, may be critical both in the development of cancer and in determining response to therapy. The authors examined the expression of two related apoptotic inhibitors, Bcl-2 and Bcl-xL, in pretreatment biopsies from a series of 42 patients with squamous cell carcinoma of the head and neck. The observed pattern of apoptotic inhibitor expression was compared with that of the p53 gene product, another factor implicated in carcinogenesis and therapeutic responsiveness. METHODS: Formalin fixed, paraffin embedded tumor biopsies from 42 patients with locally advanced squamous cell carcinoma of the head and neck were analyzed by immunohistochemistry using antibodies specific for Bcl-xL, Bcl-2, and p53. Measures of clinical outcome, including disease specific survival and overall survival, were compared among the groups. RESULTS: The majority of the tumors demonstrated enhanced expression of either Bcl-2 or Bcl-xL compared with surrounding normal epithelium. Fifty-two percent of the tumors had up-regulated Bcl-xL, and 17% had up-regulated Bcl-2. There was no overlap between these groups. Expression of Bcl-2, but not Bcl-xL, was correlated with improved disease specific survival. Immunohistochemically detectable p53 expression (48% of tumors) was not found to correlate with expression of either Bcl-xL or Bcl-2 and, in this series, was not a predictor of clinical outcome. CONCLUSIONS: These results suggest that disruption of apoptotic control pathways is an important event in the evolution of squamous cell carcinoma of the head and neck. A common mechanism for this disruption involves overexpression of Bcl-xL, Patients whose tumors demonstrate Bcl-2 positivity, even with locoregionally advanced disease, appear to have a high likelihood of cure with aggressive combined modality therapy and may be treated successfully with less toxic therapy.

Carcinoma, Squamous Cell↗
PubMed1999

Early release of mitochondrial cytochrome c and expression of mitochondrial epitope 7A6 with a porphyrin-derived photosensitizer: Bcl-2 and Bcl-xL overexpression do not prevent early mitochondrial events but still depress caspase activity.

Certain nonmetallic porphyrins have potent antitumor activity upon visible light irradiation. Treatment of HeLa cells with nanomolar amounts of the photochemo therapeutic agent verteporfin and red light mobilized caspases 2, 3, 6, 7, 8, and 9, caused degradation of specific caspase substrates, and resulted in morphologic changes consistent with apoptosis. Caspase processing was detectable by 1 hour after light irradiation. The mitochondrial 7A6 epitope, recognized by monoclonal antibody APO2.7, became accessible, and cytochrome c was detectable within the cytosolic fraction of cells treated with verteporfin immediately after light irradiation. The general caspase inhibitor benzyloxycarboyl-Val-Ala-Asp-fluoromethylketone did not prevent 7A6 expression produced by photosensitization at peptide concentrations which completely prevented caspase activation and cleavage of caspase-specific substrates. Enforced overexpression of Bcl-2 or Bcl-xL prevented cytochrome c release and 7A6 expression produced by ultraviolet B light treatment, but did not prevent cytochrome c release or 7A6 expression elicited by verteporfin photosensitization. Bcl-2 or Bcl-xL overexpression delayed morphologic changes, depressed caspase activation, and limited substrate degradation, but did not protect against loss of viability after verteporfin photosensitization. This observation indicates that cells overexpressing Bcl-2 or Bcl-xL exhibit resistance to caspase activation even after the appearance of cytochrome c in the cytosol. Porphyrin photosensitizers are effective chemotherapeutic agents that elicit primary proapoptotic mitochondrial events even in the setting of heightened Bcl-2 or Bcl-xL expression.

Animals↗
PubMed1998

Signal transduction pathways that regulate cell survival and cell death.

Apoptosis or programmed cell death (PCD) is a physiological process critical for organ development, tissue homeostasis and elimination of defective or potentially dangerous cells in complex organisms. Apoptosis permits cell death without a concomitant inflammatory response in the surrounding tissues. The process of apoptosis depends on the reception of multiple extracellular and intracellular signals, integration and amplification of these signals by second messengers and finally, activation of the death effector proteases. Defects in control of apoptotic pathways may contribute to a variety of diseases including cancer, autoimmune and neurodegenerative conditions and AIDS. While many components of the regulatory network controlling apoptosis have been defined, the mechanisms of action and patterns of interaction of these factors remain controversial. This article summarizes some of the known aspects of signaling pathways involved in apoptosis.

Animals↗
PubMed1998

Bcl-xL is phosphorylated in malignant cells following microtubule disruption.

The oncogenic protein Bcl-2 functions as a potent inhibitor of programmed cell death. This survival activity has been shown in some settings to be influenced by the Bcl-2 phosphorylation state. It has been demonstrated that treatment with microtubule-targeted agents results in phosphorylation of both Raf-1 kinase and Bcl-2. The Bcl-2-related family member Bcl-xL also exhibits a death suppressive activity, but its potential for phosphorylation following exposure to drugs that interact with microtubules has not been evaluated. Several tumor cell lines with low or undetectable levels of Bcl-2 protein expression were found to express Bcl-xL. A more slowly migrating Bcl-xL band was observed on immunoblots after cells were treated with microtubule-targeted agents. The appearance of this band was responsive to dose and was absent when the cell lysates were treated with lambda protein phosphatase. Using a Bcl-xL-specific monoclonal antibody, the phosphorylated form of Bcl-xL was immunoprecipitated from cells treated with paclitaxel and metabolically labeled with 32P-labeled inorganic orthophosphate. Herein, we report that Bcl-xL is phosphorylated in malignant cells after incubation with agents that target tubulin, including paclitaxel, vincristine, vinblastine, colchicine, and nocodazole. Moreover, paclitaxel-resistant ovarian carcinoma cell lines that have mutations in tubulin failed to exhibit phosphorylation of Bcl-xL after paclitaxel exposure, but they did demonstrate Bcl-xL phosphorylation in the presence of other tubulin-targeting agents. As observed for Bcl-2, phosphorylation of Bcl-xL was accompanied by phosphorylation of Raf-1. Interestingly, phosphorylation of these three proteins failed to occur or was much less pronounced when cells grown at high density were challenged with drug. Also, reduced Raf-1 expression, observed after treatment of cells with geldanamycin prior to and during incubation with the microtubule-active drugs, correlated with diminished Bcl-xL phosphorylation. Taken together, these results suggest that Bcl-xL, like Bcl-2, is phosphorylated by agents that disrupt microtubule architecture. By analogy with Bcl-2, this phosphorylation may play a critical role in modulating Bcl-xL function and may be an important determinant of microtubule-directed chemotherapeutic efficacy in human tumors.

Antibiotics, Antineoplastic↗
PubMed1998

A Bcl-xL transgene promotes malignant conversion of chemically initiated skin papillomas.

The role of apoptosis in the pathogenesis of skin cancer was analyzed in mice bearing a Bcl-xL transgene expressed under the control of the keratin 14 promoter. No spontaneous tumors developed in the skin of these transgenic mice. Bcl-xL transgenics also failed to develop skin lesions following treatment with the chemical mutagen 9,10-dimethyl-1,2-benzanthracene, or the tumor promoter O-tetradecanoylphorbol-13-acetate. However, Bcl-xL transgenics developed a two-fold greater number of benign papillomas than control littermates following treatment with the combination of 9,10-dimethyl-1,2-benzanthracene and O-tetradecanoylphorbol-13-acetate. More significantly, Bcl-xL transgenic mice developed invasive squamous cell carcinoma earlier and more frequently than wild-type controls in response to the chemical agents. These data suggest that Bcl-xL cannot functionally substitute for a mutagenic initiator or mitogenic promoter in tumorigenesis. In contrast, Bcl-xL overexpression can dramatically increase the malignant conversion rate of benign tumors, suggesting that inhibition of apoptosis can contribute to tumor progression.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

B-cell development and maturation.

Approximately 85% of all non-Hodgkin's lymphomas arise from cells of the B lineage. Sequential stages of B-cell development have been defined by molecular markers, and these markers can be used to reclassify lymphoid malignancies as representing maturational arrest and immortalization at specific points in B-cell ontogeny. Several of the factors controlling the ordered rearrangement and expression of the immunoglobulin (Ig) genes have been identified. Signals generated by intermediates in Ig gene rearrangement, as well as by the complete Ig molecule, have been found to be critical in guiding early B-cell development. The processes of peripheral B-cell activation, antigenic affinity maturation, and terminal B-cell differentiation are also highly regulated. The molecular mechanisms responsible for both promoting and attenuating B-cell (humoral) immune responses have been increasingly well defined. This review summarizes some aspects of the current understanding of normal B-cell development, maturation, activation, and death, focusing on the factors implicated in regulating progression through these stages.

Animals↗
PubMed1997

Apoptosis and disease: regulation and clinical relevance of programmed cell death.

Regulation of the homeostatic balance between cell proliferation and cell death is essential for development and maintenance of multicellular organisms. Physiologic, or programmed, cell death is dependent on a genetically encoded and evolutionarily conserved pathway that induces a form of cellular suicide known as apoptosis. In the past decade, it has become clear that the regulatory mechanisms controlling programmed cell death are as fundamental, and as complex, as those regulating cell proliferation. Perturbation of the signaling cascades regulating apoptosis, whether by extracellular triggers, acquired or germline genetic mutations, or viral mimicry of signaling molecules, can result in a wide variety of human diseases. Analysis of these regulatory pathways has led to a better understanding of the etiology and pathogenesis of many human diseases, notably cancers, infectious diseases including AIDS, autoimmune diseases, and neurodegenerative/neurodevelopmental diseases. Our understanding of the regulation of programmed cell death in health and disease is far from complete, and the challenge of converting that understanding into new therapeutic modalities has only begun to be approached.

Animals↗
PubMed1996

Apoptotic signaling in lymphocytes.

Two families of cell surface receptors are integral to the control of lymphocyte survival and programmed cell death (apoptosis): the tumor necrosis factor receptor family and the CD28/CTLA4 family. Tumor necrosis factor receptor family members bind a related collection of ligands (the tumor necrosis factor family) that can either induce or inhibit cell death. Two of the tumor necrosis factor receptor family members, tumor necrosis factor receptor 1 and Fas, have been implicated in the termination of immune responses through their ability to induce apoptosis. A number of cytoplasmic proteins implicated in signal generation by these receptors recently have been identified. These proteins fall into several related classes sharing intriguing structural motifs. The CD28 and CTLA4 molecules share at least two extracellular ligands and signaling through the two receptors appears to determine the apoptotic sensitivity of activated T cells. The effects of CD28 and CTLA4 on cell survival are dependent on T-cell antigen receptor engagement, providing a potent mechanism for clonally specific T-cell expansion or deletion. The study of the apoptotic pathways in lymphocytes has led to a better understanding of the mechanisms of autoimmune disease and serves as a model system for the study of the regulation of cell survival and tissue homeostasis.

Abatacept↗
PubMed1995

Expression of bcl-xL can confer a multidrug resistance phenotype.

It has been suggested that genes that regulate apoptotic cell death may play an important role in determining the sensitivity of tumor cells to chemotherapy. We have recently cloned a member of the bcl-2 family, bcl-x. To test whether bcl-XL expression affects the sensitivity of tumor cells to chemotherapy, we have created stable cell lines overexpressing bcl-XL and have tested these cells for resistance to cell death induced by metabolic inhibitors and chemotherapeutic agents. Bcl-XL expression dramatically reduces the cytotoxicity of bleomycin, cisplatin, etoposide, vincristine, hygromycin B, and mycophenolic acid for up to 4 days in culture. Bcl-XL does not prevent cells from undergoing cell cycle arrest in response to these drugs, but rather prevents treated cells from undergoing apoptosis. Cell-cycle analysis on cells treated with the chemotherapeutic agents bleomycin, cisplatin, etoposide, and vincristine, show that the drugs cause growth arrest in different positions within the cell cycle. Bcl-XL expressing cells treated with chemotherapeutic drugs retain their proliferative ability after the drugs are removed. Interestingly, vincristine-treated cells expressing bcl-XL become polyploid after drug removal. These data show that bcl-XL protects cells from a wide variety of apoptotic stimuli, acts in multiple positions within the cell cycle, and confers a multidrug resistance phenotype. The ability of bcl-XL to prevent apoptotic cell death in response to chemotherapy-induced DNA damage and cell-cycle arrest may contribute to the accumulation of chromosomal aberrations within tumors. The expression of bcl-XL in tumor cells is likely to be an important indicator of chemotherapeutic efficacy.

Animals↗
PubMed1992

Two conserved essential motifs of the murine immunoglobulin lambda enhancers bind B-cell-specific factors.

Two highly homologous enhancers associated with the two murine immunoglobulin lambda constant-region clusters were recently identified. In order to better understand the molecular basis for the developmental stage- and cell-type-restricted expression of lambda genes, we have undertaken an analysis of the putative regulatory domains of these enhancers. By using a combination of DNase I footprinting, electrophoretic mobility shift assay, and site-specific mutations, four candidate protein binding sites have been identified at analogous positions in both enhancers. A mutation of any of these sites decreases enhancer activity. Two of the sites, lambda A and lambda B, are essential for enhancer function, and both of these sites appear to bind both B-cell-specific and general factors. Nevertheless, isolated lambda A and lambda B sites show no evidence of inherent transactivating potential, alone or together, even when present in up to three copies. We suggest that the generation of transactivating signals from these enhancers may require the complex interaction of multiple B-cell-specific and nonspecific DNA-binding factors.

Animals↗