Clin Cancer Res
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Coordinated presentation of antigen and costimulatory molecules has been shown to result in the induction of an antigen-specific T-cell response rather than the development of anergy. This study evaluated the vaccine ALVAC-CEA B7.1, a canary pox virus that has been engineered to encode the gene for the tumor-associated antigen carcinoembryonic antigen (CEA) and B7.1, a T-cell costimulatory molecule. Patients with CEA-expressing tumors were immunized with 2.5 x 10(7) (n = 3), 1.0 x 10(8) (n = 6), and 4.5 x 10(8) (n = 30) plaque-forming units intradermally every other week for 8 weeks. ⋯ After four vaccinations, patients who were HLA-A-2-positive demonstrated increases in their CEA-specific T-cell precursor frequencies to a CEA-A2-binding peptide from baseline. The number of prior chemotherapy regimens was inversely correlated with the ability to generate a T-cell response. ALVAC-CEA B7.1 is safe in patients with advanced, recurrent adenocarcinomas that express CEA, and it is associated with the induction of a CEA-specific T-cell response.
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The antitumor effects of the selective cyclooxygenase (COX)-2 inhibitor SC-236 alone and in combination with radiation were investigated using the human glioma cell line U251 grown in monolayer culture and as tumor xenografts. On the basis of Western and Northern blot analyses, these cells express COX-2 protein and mRNA to levels similar to those in the human colon carcinoma cell line HT29. Treatment of U251 cells in monolayer culture with 50 microM SC-236 resulted in a time-dependent decrease in cell survival as determined by a clonogenic assay. ⋯ To extend these investigations to an in vivo situation, U251 glioma cells were grown as tumor xenografts in the hind leg of nude mice, and SC-236 was administered in drinking water. SC-236 alone slowed tumor growth rate, and when administered in combination with local irradiation, SC-236 caused a greater than additive increase in tumor growth delay. These in vitro and in vivo results suggest that the selective inhibition of COX-2 combined with radiation has potential as a cancer treatment.
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Raf proteins play a central role in the mitogen-activated protein kinase signaling pathway and hence are involved in oncogenic transformation and tumor cell proliferation. ISIS 5132 is a 20-base antisense phosphorothioate oligodeoxyribonucleotide that specifically down-regulates c-raf expression. We report here an initial study of the safety and tolerability of an i.v. infusion of ISIS 5132 in patients with advanced cancer. ⋯ Side effects were minimal and could not be specifically related to ISIS 5132. Two patients had prolonged stabilization of their disease, and one patient with ovarian carcinoma had a significant response with a 97% reduction in CA-125 levels. ISIS 5132, an antisense oligonucleotide against c-raf, was well tolerated at doses up to and including 4.0 mg/kg/day by 21-day continuous i.v. infusion and demonstrated antitumor activity at the doses tested.
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CGP 57148 is a potent inhibitor of the ABL protein tyrosine kinase and a promising new compound for the treatment of a variety of BCR-ABL-positive leukemias. We used this enzyme inhibitor to characterize the biological effects of BCR-ABL in primary cells and two growth factor-dependent BCR-ABL-transfected cell lines. The effect of CGP 57148 on primary cells is dependent on the stage of differentiation. ⋯ Inhibitors of signal transduction proteins such as PI-3 kinase, mitogen-activated protein/extracellular signal-regulated kinase kinase, and Janus-activated kinase 2 pathways were not capable of a comparable down-regulation of BCL-X. The Fas/Fas ligand system was not involved either in the induction of apoptosis by CGP 57148. We conclude that the inhibition of the BCR-ABL kinase by CGP 57148 (a) preferentially inhibits the growth of immature leukemic precursor cells, (b) efficiently reverts the antiapoptotic effects of BCR-ABL by down-regulation of BCL-X, and (c) is more effective than the inhibition of the downstream signal transduction pathways of PI-3 kinase, mitogen-activated protein/extracellular signal-regulated kinase kinase, and Janus-activated kinase 2.
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Although numerous chemotherapeutic regimens have been evaluated for patients with hormone-refractory prostate cancer, none has improved survival. Testosterone-repressed prostate message-2 (TRPM-2), which is highly up-regulated after androgen withdrawal and during androgen-independent progression in prostate cancer, has been shown to inhibit apoptosis induced by various kinds of stimuli. The objectives in this study were to test whether antisense (AS) oligodeoxynucleotides (ODNs) targeted against TRPM-2 enhance chemosensitivity in human androgen-independent prostate cancer PC-3 cells both in vitro and in vivo. ⋯ In vivo administration of AS ODN#2 plus either paclitaxel or mitoxantrone significantly decreased PC-3 tumor volume by 80 or 60%, respectively, compared with mismatch control ODN plus either paclitaxel or mitoxantrone. In addition, terminal deoxynucleotidyl transferase-mediated nick end labeling staining revealed increased apoptotic cells in tumors treated with AS ODN#2 plus paclitaxel or mitoxantrone. These findings confirm that TRPM-2 overexpression confers resistance to cytotoxic chemotherapy in prostate cancer cells and illustrates the potential utility of combined treatment with AS TRPM-2 ODN plus chemotherapeutic agents for patients with hormone-refractory prostate cancer.