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Biomedical subjects

Robert L Fine

Publications and source records attributed to Robert L Fine.

28 records · Page 2Linked to original sources

Pancreatic cancer and thromboembolic disease.

Thromboembolic disease is a common complication of pancreatic cancer and is causally associated with the generation of an intrinsic hypercoagulable state. Pancreatic-cancer cells activate platelets and express several procoagulant factors, including tissue factor and thrombin. The activation of coagulation is not simply an epiphenomenon, but might also be related to enhanced tumour growth and angiogenesis. Clinical manifestations of thromboembolic disease in pancreatic cancer include deep venous thrombosis, pulmonary embolism, disseminated intravascular coagulation, portal vein thrombosis, and arterial thromboembolism. Reported incidences of disease range from 17% to 57%. Treatment options include warfarin and low-molecular-weight heparins. Studies over the past decade suggest that long-term use of these heparins in both primary and secondary prevention of venous thromboembolic disease improves outcomes in comparison with warfarin. Further research is needed to understand better the morbidity and mortality associated with this disease in pancreatic cancer and to optimise strategies of prevention and treatment.

Anticoagulants↗

The imperative for hospital-based palliative care: patient, institutional, and societal benefits.

Challenges in societal demographics, finances, and human suffering are pushing us towards a new paradigm in health care delivery. The palliative care paradigm is a necessary complement to existing acute care and chronic care paradigms. Palliative care does not replace prior paradigms; instead, it adds value and provides a shift in focus when appropriate. Baylor University Medical Center has all of the components needed for an effective palliative care program, including expertise in palliative medicine, pain management, ethics, geriatrics, oncology, other medical specialties, nursing, social work, and pastoral care. The palliative care consultation service will enhance patient care and improve financial performance in patients with serious life-limiting illnesses.

Journal Article↗

Resolution of futility by due process: early experience with the Texas Advance Directives Act.

Every U.S. state has developed legal rules to address end-of-life decision making. No law to date has effectively dealt with medical futility--an issue that has engendered significant debate in the medical and legal literature, many court cases, and a formal opinion from the American Medical Association's Council on Ethical and Judicial Affairs. In 1999, Texas was the first state to adopt a law regulating end-of-life decisions, providing a legislatively sanctioned, extrajudicial, due process mechanism for resolving medical futility disputes and other end-of-life ethical disagreements. After 2 years of practical experience with this law, data collected at a large tertiary care teaching hospital strongly suggest that the law represents a first step toward practical resolution of this controversial area of modern health care. As such, the law may be of interest to practitioners, patients, and legislators elsewhere.

Advance Directives↗

Fas-mediated apoptosis is dependent on wild-type p53 status in human cancer cells expressing a temperature-sensitive p53 mutant alanine-143.

The p53 mutant 143Ala is a human temperature-sensitive mutant with two conformational states. To definitively determine whether the Fas signal transduction pathway and the function of the pathway are dependent on p53 status, we have established stable transfectants of p53 mutant 143Ala in two human cancer cell lines: H1299 (lung cancer line) and PC-3 (prostate cancer line), the native state of which contains null p53 status and can grow at 37 degrees C and 32.5 degrees C. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and cell cycle analysis showed inhibition of the growth of cells overexpressing p53 mutant 143Ala in the wild-type p53 form at 32.5 degrees C because of induction of G0/G1 arrest. Transfected cells had increased protein expression of p21, Fas, and MDM2 at the wild-type p53 conformation at 32.5 degrees C, but not in the mutant p53 form at 37 degrees C. However, there was no change in protein expression of FADD, FAP-1, Bcl-2, or Bax at 32.5 or 37 degrees C. Assays for apoptosis demonstrated that anti-Fas antibody CH-11 and FasL induced apoptosis only in cells that overexpress p53 mutant 143Ala at 32.5 degrees C with the wild-type p53 form. Both caspase-3 and caspase-8 activities were increased by anti-Fas antibody CH-11 only in cells at 32.5 degrees C with wild-type p53. Our results demonstrated that Fas-mediated apoptosis in H1299 and PC-3 cells expressing p53 mutant 143Ala occurred only with the wild-type p53 phenotype. These results support the hypothesis that Fas-mediated apoptosis is dependent, at least partially, on the presence of a functional wild-type p53 state. This model may be a useful tool for dissecting the specific interactions between wild-type p53 and the Fas signal transduction pathway in human cancer cells.

Adenocarcinoma↗

Preferential induction of necrosis in human breast cancer cells by a p53 peptide derived from the MDM2 binding site.

p53 is the most frequently altered gene in human cancer and therefore represents an ideal target for cancer therapy. Several amino terminal p53-derived synthetic peptides were tested for their antiproliferative effects on breast cancer cell lines MDA-MB-468 (mutant p53), MCF-7 (overexpressed wild-type p53), and MDA-MB-157 (null p53). p53(15)Ant peptide representing the majority of the mouse double minute clone 2 binding site on p53 (amino acids 12-26) fused to the Drosophila carrier protein Antennapedia was the most effective. p53(15)Ant peptide induced rapid, nonapoptotic cell death resembling necrosis in all breast cancer cells; however, minimal cytotoxicity was observed in the nonmalignant breast epithelial cells MCF-10-2A and MCF-10F. Bioinformatic/biophysical analysis utilizing hydrophobic moment and secondary structure predictions as well as circular dichroism spectroscopy revealed an alpha-helical hydrophobic peptide structure with membrane disruptive potential. Based on these findings, p53(15)Ant peptide may be a novel peptide cancer therapeutic because it induces necrotic cell death and not apoptosis, which is uncommon in traditional cancer therapy.

Amino Acid Chloromethyl Ketones↗

Correlation between hydrophobic properties and efficiency of carrier-mediated membrane transduction and apoptosis of a p53 C-terminal peptide.

Two membrane transporters, the 17 amino acid (aa) oligopeptide penetratin derived from the homeodomain of Antennapedia (Ant) and an analogue of the basic domain of TAT (aa 47-57) (TAT-a) from HIV-1, were tested as carriers for a p53 C-terminal peptide (aa 361-382) into human breast cancer cells. The studies were performed to determine whether the membrane-transduction efficiency of membrane carriers: Ant, TAT or TAT analogue (TAT-a) correlated with peptide hydrophobic features. Peptide-sequence analysis clearly demonstrated that the Ant sequence and p53 peptide sequence (p53p) together created a peptide with enhanced hydrophobic characteristics; while the TAT or TAT analogue (TAT-a) and p53p sequence together created a peptide with significantly less hydrophobic qualities. The degree of hydrophobic moment and helical wheel plots for these peptides correlated directly with their ability to transduce the p53 peptide. Western blot analysis revealed that Ant was able to transduce p53 C-terminal peptide into human breast cancer cells as a highly efficient membrane transporter. Compared to Ant, TAT-a fused to the C-terminus of p53 peptide (p53p-TAT-a) was a less efficient carrier into these cells under the conditions of our study. Additionally, N-terminal linked TAT-a to p53p (TAT-a-p53p) showed even lower efficiency as a transporter than p53-TAT-a. Apoptosis assays showed that the p53 peptide, fused at its C-terminus to Ant (p53p-Ant), induced a higher percentage of apoptotic cells in human breast cancer cell lines expressing mutant or wild-type p53 as compared to p53 peptide fused at its C-terminus to the TAT-a sequence (p53p-TAT-a) or when fused at the N-terminus to TAT-a (TAT-a-p53p). These data suggested a direct correlation between hydrophobic characteristics and efficiency as a transporter. Sequence study, using hydrophobic moment and helical wheel analyses, may be useful predictive tools for choosing the best carrier for a peptide.

Amino Acid Sequence↗

A novel stereo-selective sulfonylurea, 1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one, has antitumor efficacy in in vitro and in vivo tumor models.

The antitumor activities of novel 1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-ones were studied to determine the potential of these compounds as antitumor candidates. The agents studied were: DW2143 (1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one), a racemic mixture, and DW2282 [(4S)-1-[1-(4-aminobenzoyl)-2,3-dihydro-1H-indol-6-sulfonyl]-4-phenyl-imidazolidin-2-one], an S-isomer. DW2143 and DW2282 suppressed the in vitro growth of tumor cells at lower concentrations than doxorubicin, but tumor specificity was not observed between the compounds. These compounds when administered orally were not active in syngeneic models of murine Colon 26 adenocarcinoma and L1210 leukemia. However, DW2143 suppressed the growth of SW620 (human colon cancer) and NCI-H23 (human lung cancer) cells in nude mice, inhibiting tumor growth by 87 and 67%, respectively. DW2282 was a more potent inhibitor of SW620 tumor cell growth in nude mice and was also lower in toxicity than DW2143. Moreover, DW2282 did not produce a series of toxic symptoms caused by the aniline metabolites of sulfonylureas, including hypoglycemia. These results suggest that DW2282, an S-isomer, could be a novel antitumor candidate with higher specificity and lower toxicity than other orally active sulfonylureas.

Animals↗

The novel antimicrotubule agent cryptophycin 52 (LY355703) induces apoptosis via multiple pathways in human prostate cancer cells.

We assessed the ability of cryptophycin 52 (LY355703), a novel antimicrotubule, to induce growth arrest and apoptosis in prostate cancer cell lines and investigated potential molecular mechanisms of death. LNCaP (androgen-dependent) and DU-145 (androgen-independent) cells accumulated in G(2)-M phase of the cell cycle and progressively acquired sub-G(0)-G(1) DNA content after 48 h of exposure to cryptophycin 52 (1-10 pM). Induction of apoptosis was confirmed by DNA ladder formation and detection of cytoplasmic nucleosomes. PC-3 (androgen-independent) cells were less responsive to cryptophycin 52-induced death. Apoptosis was associated with proteolytic processing and activation of the caspase-3-like subfamily proteins caspase-3 and caspase-7 and cleavage of the caspase substrate poly(ADP-ribose) polymerase. The pan-caspase inhibitor BOC-Asp(OMe)-fluoromethylketone effectively reduced cryptophycin 52-induced caspase-3-like protease activity and apoptosis in DU-145 cells. In contrast, BOC-Asp(OMe)-fluoromethylketone did not inhibit apoptosis induction in LNCaP cells by cryptophycin 52, even though both cryptophycin 52-induced caspase-3-like activity and staurosporine-induced death were blocked under identical conditions. Cryptophycin 52 induced phosphorylation of c-raf1 and bcl-2 and/or bcl-x(L) to comparable levels in all cell lines studied, and LNCaP cells overexpressing bcl-2 were more resistant to cryptophycin 52-induced apoptosis. Up-regulation of p53, bax, and p21 expression was induced in wild-type p53-expressing LNCaP cells only after cryptophycin 52 exposure. A sustained increase in c-Jun NH(2)-terminal kinase phosphorylation was also observed, the levels of which strongly correlated with apoptosis. We conclude that apoptosis induced by cryptophycin 52 in prostate cancer cells is androgen status independent, cell type specific for caspase requirement, modulated by the bcl-2 family, linked to but not dependent on p53, and strongly correlated with c-Jun NH(2)-terminal kinase phosphorylation. Cryptophycin 52-induced apoptosis in prostate cancer cells is therefore associated with multiple cell line-specific alterations in apoptosis-associated proteins and pathways.

Androgens↗