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Despite progress in chemotherapeutic agents, non-small cell lung cancers (NSCLC) still have a poor survival rate. Thus, development of new therapeutic strategies, specifically against cancer cells is still required. For this purpose, we treated the non-small cell lung cancer cell line NSCLC-N6 with the natural product cucurbitacin D (CucD) - extracted from the plant Ecballium elaterium in order first to assess its in vitro cytotoxicity, but also to study the genetic changes that it could bring out. CucD has shown a blocking in the G1 phase of the cell cycle in NSCLC-N6 cells prior to apoptotic cell death. The reverse transcriptase-polymerase chain reaction-differential display (RT-PCR-DD) technique was also applied on treated cells to elucidate the genetic mechanisms involved. We revealed an overexpression of Cyclin-dependent kinase 1 (CDK1) mRNA after treatment and, with the use of antisense oligonucleotides, an effective role in the proliferation arrest of NSCLC-N6 cells. The present study provides new insights about the mechanisms of proliferation arrest in tumor cells and open new ways of treatment to target tumor growth., (Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.)

Non-small cell lung cancers remain particularly refractory to current treatments. Thus, characterisation of new molecular targets whose expression during chemotherapy could stop tumour growth, is required. In order to identify these new targets, we applied RT-PCR differential display (RT-PCR-DD) to a non-small cell lung cancer line (NSCLC-N6) treated by an original chemical substance, VT1, capable of arresting the proliferation of NSCLC-N6 cells in G1 phase. This study enabled us to identify a novel RNA, which has a strong homology with a DNA clone (GenBank accession no.: AY166681). This RNA resides in 6p24-p25 within intron 2 of the HEF1 gene, has no apparent open reading frame and may consists of a single large exon. Antisense oligonucleotides indicated that this RNA is involved in the proliferation arrest induced with VT1 treatment in NSCLC-N6 cells. The structure of this novel RNA resembles that of the previous identified extremely long non-coding RNAs which seem to regulate gene expression. Thus, this novel B2 transcript may belong to this new expanding non-coding RNA family.

Despite new protocols, non-small cell bronchopulmonary cancers are still difficult to treat by current chemotherapeutic procedures. Thus, it is essential to define new treatment strategies and detect new therapeutic targets. In order to define these new targets, this study applied the "differential display" (DD) technique to the NSCLC-N6 cell line treated with VT1 [methyl-4-methoxy-3-(3-methyl-2-butanoyl)benzoate]. VT1 induces arrest of the NSCLC-N6 cell cycle in the G1-phase, followed by cell death. DD enabled us to detect seven overexpressed mRNAs during treatment, four of which corresponded to identified genes: aldehyde dehydrogenase 1, nuclear transcription factor Nrfl, junctional adhesion molecule, and amino-ketobutyrate ligase. An antisense strategy showed that amino-ketobutyrate ligase is involved in the proliferation arrest of NSCLC-N6 cells in the G1-phase after VT1 treatment.

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. Application of "antisense" strategy confirmed this novel mRNA induction was effectively linked to growth arrest. Therefore, these data provide new information about mechanisms participating in arrest of proliferation of tumor cells and open new ways of treatment to target tumor growth., (Copyright 2001 Wiley-Liss, Inc.)

An aqueous extract of the marine diatom Haslea ostrearia (Simonsen) was studied for its antiproliferative properties against human solid tumors: lung carcinoma (NSCLC-N6), kidney carcinoma (E39) and melanoma (M96). These types of carcinoma are particularly chemoresistant. The extract has a potent cytostatic effect in vitro on the three cell lines and blocks the NSCLC-N6 line in the G1/S phase of the cell cycle. Moreover, the extract strongly inhibits tumor growth of NSCLC-N6 bearing nude mice. These preliminary results indicate that the aqueous extract of Haslea ostrearia exhibits inhibitory effects both in vitro and in vivo against solid carcinoma lines, suggesting the presence of a new potent antitumor agent in the aqueous algal homogenate.