Up-regulation of a novel mRNA (NY-CO-1) involved in the methyl 4-methoxy-3-(3-methyl-2-butenoyl) benzoate (VT1)-induced proliferation arrest of a non-small-cell lung carcinoma cell line (NSCLC-N6)

Abstract

It is now well known that treatment of tumors, especially non-small-cell lung cancer (NSCLC), remains limited and it is urgent to develop strategies that target tumor cells and their genetic features. In this regard, our work is about genetic modifications arising in an in vitro NSCLC cell line after treatment with a chemical substance, methyl 4-methoxy-3-(3-methyl-2-butenoyl) benzoate (VT1). First, we showed that VT1 induces arrest of proliferation by blocking cells in the G1 phase of the cell cycle. Second, we use "differential display" strategy to clarify the genetic mechanisms involved in this proliferation arrest. A novel mRNA, NY-CO-1 (New-York Colon 1), of unknown function showed up-regulated expression after treatment. The use of chemotherapeutic agents in the treatment of tumors is limited by several factors including innate or acquired drug resistance and systemic toxicity. 1 In bronchopulmonary carcinomas, chemotherapy remains relatively inactive against these cancers, with a poor response rate and a survival benefit limited to a period of a few weeks or months. 2,3 Accordingly, new treatment approaches need to be considered.In this context, the first purpose of our study was to investigate the biological activity of a chemical constituent, methyl 4-methoxy-3-(3-methyl-2-butenoyl) benzoate, also named VT1, in an NSCLC cell line derived from a human non-small-cell lung carcinoma. VT1 is a synthetic molecule obtained after chemical modifications of a precursor molecule of natural origin extracted from Piper-Toboganum. 4 The NSCLC cell line shows a chemosensitivity for conventional drugs close to clinical doses, making it an excellent model for studying the biological activity of new products, 5 including marine substances that have shown biological activity on this cell line. 6 -8 The present study, which investigated VT1 cellular and molecular mechanisms of action on the human NSCLC cell line, found that proliferation could be stopped by incubation with VT1. The cellular mechanisms involved induction of programmed cell death of apoptotic type, which was associated with cellular morphological modifications and cell cycle blockade in the G1 phase.Many studies have presented previously genetic factors involved in cell death. They include nuclear factors like p53 and its partners, p21 and GADD45, 9 but also cytoplasmic and extracellular factors like the bcl-2 gene family, 10 caspases 11 or FAS ligand and TNF␣. 12 In tumor cells these factors are often inactive (mutation in the p53 gene), but it is possible to engage these cells in a programmed cell death after treatment by a certain type of substance. The latter shows that other genetic factors implicated in programmed cell death should exist and, finally, that tumor cells are a good model for characterizing them.Thus, the second purpose of our study was to clarify the genetic mechanisms involved in proliferation arrest of the human NSCLC-N6 cell line after treatment, which led us to employ the "differential display" strategy. This powerful method makes ...

Kavalactones and Benzoic Acid Derivatives from Leaves of Piper fuligineum Kunth (Piperaceae)

“…Thus, compound 6 was established as methyl 4-methoxy-3-(3-methylbut-2-enoyl)benzoate, a methylated derivative of methyl taboganate. 36 The biogenesis involved in the formation of kavalactones and benzoic acid derivatives in P. fuligineum suggests that shikimic acid is the key building block in their formation (Figure 1). Additionally, the oxidation level of the benzoic acid derivatives in P. fuligineum indicates that such oxidations are important processes for achieving the chemical diversity observed for the kavalactones and benzoic acid derivatives, which includes a chromanone.…”

Drosophila caliban, a nuclear export mediator, can function as a tumor suppressor in human lung cancer cells

“…Activation of human Sdccag1 had been reported to result in G0/G1 cell cycle arrest in NSCLC-N6 cells (Carbonnelle et al, 2001); however, the constitutive expression of fly Clbn neither results in arrest nor changes the length of the cell cycle of A549 (approximately 24 h) and EKVX (approximately 48 h) cells. Furthermore, inhibition of human Sdccag1 with shRNAs also did not appear to have an effect on the cell cycle lengths of NHBE and WI-38 cells.…”

“…Human Sdccag1 has been implicated in colon and lung cancers, but its biochemical function was unknown (Scanlan et al, 1998;Carbonnelle et al, 2001). To determine the biological function of the fly homolog Clbn, we transfected Drosophila SL2 tissue culture cells with a green fluorescent tagged NES, pAc5.1-EYFP-HDA, and used RNAi to determine whether Clbn and/ or the Drosophila Exportin protein, encoded by embargoed (emb; Collier et al, 2000), are necessary for HDAmediated nuclear export.…”

“…It was enigmatic why Sdccag1 was cloned using SEREX (Scanlan et al, 1998), which implies that it is over-or mis-expressed in colon cancer patients, if it is in fact a human tumor suppressor (Carbonnelle et al, 2001). As the former paper described their clone of the carboxy-terminal third of Sdccag1 as full length, we reasoned that this truncated protein might function as a dominant negative.…”

“…Another group identified the protein as a tumor suppressor, as when sdccag1 was induced in a non-small-cell lung cancer cell line, NSCLC-N6, it caused a cell cycle arrest. Blocking the synthesis of Sdccag1 protein with antisense RNA reverted the cells to cancer (Carbonnelle et al, 2001).…”