s-trans-trans-farnesylthiosalicylic-acid and Lung-Neoplasms

KRAS mutations are present in 30% of lung adenocarcinomas. Salirasib prevents Ras membrane binding thereby blocking the function of all Ras isoforms. This phase II study determined the activity of salirasib in patients with advanced lung adenocarcinomas with KRAS mutations.. Two cohorts of patients with stage IIIB/IV lung adenocarcinoma were eligible: patients with tumors with KRAS mutations who were previously treated with chemotherapy and patients receiving initial therapy who had ≥15 pack-year smoking history. Salirasib was given orally from days 1 to 28 of a 35-day cycle. The primary end point was the rate of nonprogression at 10 weeks.. Thirty-three patients were enrolled. Thirty patients had KRAS mutations (23 patients who were previously treated and 7/10 patients who had no prior therapy). Of the previously treated patients, 7 of 23 (30%) had stable disease at 10 weeks, and 4 of 10 (40%) previously untreated patients had stable disease at 10 weeks. No patient had a radiographic partial response (0% observed rate, 95% confidence interval 0-12%). The median overall survival was not reached (>9 months) for previously untreated patients and it was 15 months for patients who received prior chemotherapy. Diarrhea, nausea, and fatigue were the most common toxicities.. Salirasib at the current dose and schedule has insufficient activity in the treatment of KRAS mutant lung adenocarcinoma to warrant further evaluation. The successful enrollment of 30 patients with tumors with KRAS mutant lung adenocarcinoma over 15 months at a single site demonstrates that drug trials directed at a KRAS-specific genotype in lung cancer are feasible.

Topics: Adenocarcinoma; Aged; Antineoplastic Agents; Carcinoma, Non-Small-Cell Lung; DNA, Neoplasm; Farnesol; Female; Follow-Up Studies; Humans; Lung Neoplasms; Male; Middle Aged; Mutation; Neoplasm Staging; Polymerase Chain Reaction; Proto-Oncogene Proteins; Proto-Oncogene Proteins p21(ras); ras Proteins; Salicylates; Survival Rate; Treatment Outcome

Histone deacetylase (HDAC) inhibitors, such as valproic acid (VPA), constitute a novel class of anticancer agents that cause an increase in acetylated histones and thus restore the expression of dormant tumor-suppressor and other genes related to cell differentiation, cell-cycle arrest or apoptosis of tumor cells. The Ras inhibitor farnesylthiosalicylic acid (FTS, salirasib) attenuates cancer cell proliferation in vitro and in vivo and, under certain circumstances, induces cell death. FTS by itself does not induce differentiation or complete growth arrest. The abovementioned activity of VPA as a differentiation agent suggested that it might be worth investigating its possible therapeutic potential in synergistic combination with FTS. Here, we examined whether the combined application of VPA and FTS could synergistically inhibit the proliferation of cancer cells that express oncogenic K-Ras (A549 nonsmall-cell lung carcinoma cells), DLD1 (colon carcinoma cells) or chronically active wild-type K-Ras and constitutively active B-Raf (ARO, thyroid carcinoma cells). The results showed that combined treatment with VPA and FTS synergistically reduces proliferation in all of these cancer cell lines by downregulating Ras and blocking the expression of Survivin and Aurora A. These alterations, which were most pronounced following the combined treatment, led to a mitotic crisis, as reflected by mislocalization of the chromosomal passenger complex. Our findings thus demonstrate that combination therapy with VPA and FTS might offer a promising therapeutic approach to the treatment of epithelial tumors.

Topics: Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Aurora Kinases; Blotting, Western; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cell Division; Cell Line, Tumor; Colonic Neoplasms; Down-Regulation; Farnesol; Flow Cytometry; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Inhibitor of Apoptosis Proteins; Lung Neoplasms; Microtubule-Associated Proteins; Protein Serine-Threonine Kinases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Neoplasm; Salicylates; Survivin; Valproic Acid

Aberrant Ras pathway functions contribute to the malignant phenotype of lung cancers. Inhibitors of Ras might therefore be considered as potential drugs for lung cancer therapy. Here, we show that the Ras inhibitor farnesylthiosalicylic acid (salirasib) inhibits proliferation of human lung cancer cells harboring a mutated K-ras gene (A549, H23, or HTB54) or overexpressing a growth factor receptor (H1299 or HTB58) and enhances the cytotoxic effect of the chemotherapeutic drug gemcitabine. Salirasib inhibited active K-Ras in A549 cells, reversed their transformed morphology, and inhibited their anchorage-independent growth in vitro. Tumor growth in A549 and HTB58 cell nude mouse models was inhibited by i.p. administration of salirasib. P.o. formulated salirasib also inhibited A549 cell tumor growth. Our results suggest that p.o. salirasib may be considered as a potential treatment for lung cancer therapy.

Topics: Animals; Antineoplastic Agents; Cell Division; Cell Line, Tumor; Farnesol; Humans; Lung Neoplasms; Mice; Mice, Nude; ras Proteins; Salicylates

This study examined possible mechanisms for hypoxia-increased metastasis in a green fluorescent protein-labeled human fibrosarcoma cell line (HT1080). The efficiency of the lung arrest of tumor cells, which can be dependent on the adhesive potential of the tumor cells, was assessed by measuring the level of integrin alpha3beta1 protein and by adhesion assays, whereas the extravasation potential was examined by an invasion assay. These properties were not changed by exposure to hypoxia, indicating that lung arrest and extravasation are unlikely to play a major role in the effect of hypoxia on metastasis in this model. The main effect of hypoxic exposure was found to be increased survival after lung arrest as determined by clonogenic assay of tumor cells recovered from mouse lungs after i.v. injection. Concomitantly, apoptosis was identified as responsible for the death of lung-arrested cells, suggesting the involvement of an altered apoptotic response following hypoxic exposure of these cells. Consistent with this finding, we found that the effect of hypoxia on both increased metastasis and survival of arrested cells was inhibited by treatment with farnesylthiosalicylic acid. However, this effect was not due to down-regulation of hypoxia-inducible factor-1alpha, a mechanism of action of this drug reported by previous studies. Further detailed studies of the mechanisms of action of the drug are needed.

Topics: Animals; Antineoplastic Agents; Cell Adhesion; Cell Hypoxia; Cell Line, Tumor; Cell Survival; Farnesol; Fibrosarcoma; Green Fluorescent Proteins; Humans; Lung Neoplasms; Mice; Mice, SCID; Neoplasm Transplantation; Salicylates; Transplantation, Heterologous