The Research Of NKX2-1 With The Biological Effect And Anti-cancer Drug Resistance In Lung Cancer Cells

[BACKGROUND]Lung cancer is the leading cause of cancer death in the United States[1]. In recent twenty years, the total incidence of lung cancer is rising in Chinese. With the aging of population, the polluting and destroying environment, the morbidity and mortality of lung cancer are growing up. In lung cancer, the oncogenes such as MYC, KRAS, MET, EGFR, ERBB2, CCND1 and CDK4 contribute to tumor development and progression, and amplified genes have become important targets for molecularly-directed therapies[2].We have already made much progress in treatment for lung cancer, but up to now, only 15%of lung cancer patients survive 5 years after diagnosis[3]. The predominant cause of failure is believed to be distant metastases, even during in early stage[4]. So, it is important that how to detect these lung cancer early, especially those occult cancer prior to the emergence of clinical manifestations. And thus there is a need for a more sensitive and specificity marker of detecting lung cancer, above all occult cancer, and then directing the rational remedy. And now, the top thing of lung caner research is how to detect early and how to treat effectively.Nkx2-1, is Nkx2 family homeodomain-containing transcription factor, marks the region arising from lung buds. Nkx2-1 (Nkx homeobox-1 gene), also known as TTF-1 (thyroid transcription factor-1), T/EBP (thyroid-specific-enhancer-binding protein) or TITF, which was identified in 1989 as a transcription factors from rat thyroid cell line FRTL-5 which can activate the rat thyroglobulin promoter [5]. And it activates selectively in the thyroid, lung and ventral forebrain [6]. Nkx2-1 can express constantly in the human embryo and adult lung, to maintain the normal development and function. So, many disease of lung has some relationship with NKX2-1, especially lung cancer. Owing to its tissue restricted expression and recently study, have suggested that Nkx2-1 plays a role of a proto-oncogene in lung cancer and has been widely for diagnosis whether the tumor source [7-12] or malignant mesothelioma [13-16] is the lung or the other tissue. NKX2-1 is expressed highly and specifically in lung adenocarcinoma. Kwei [18] proposed that NKX2-1 maybe is a fighting-core, an indispensable factor of lung cancer and a risk reason in recurrence.NKX2-1 has specific correction with lung cancer, then, whether NKX2-1 can play a pivotal role on the development and prognosis in lung cancer? Up to now, some reports have been reported, but unfortunately, the prognostic significance between NKX2-1 and lung cancer has still unclear. Maybe, different mechanism and biology function of NKX2-1 cause the different drug-resisitance, cell proliferation and apoptosis. So, the prognostic significance of Nkx2-1 to lung cancer is different. If we can elucidate the key relation between NKX2-1 and lung cancer, we would open a new avenue to diagnose early and to treat pulmonary carcinoma effectively.[OBJECTIVE]1. Confirm the expression of NKX2-1 in different lung cancer cells and the expression in lung cancer patients.2. Confirm the relationship between NKX2-1 and the ability of proliferation, necrosis and migration of lung cancer cell.3. Confirm the effect of NKX2-1 on drug-resistance.4. Study preliminarily on the dependence of EGFR and NKX2-1. [METHODS]Part I1. To detect the protein expression of NKX2-1 in 9 lung cancer cells with western-blot.2. To select cells with different expression of NKX2-1 (low and high expression), to observe the ability of proliferation, migration, necrosis and the reaction to cisplatin.PartⅡ.1. Stable transfection NKX2-1 into NCI-H1299.2. To observe the NCI-H1299 of high-expression-Nkx2.1 (NCI-H1299Nkx2.1) in cell proliferation, migration, necrosis and the reaction to cisplatin, gefitinib, docetaxel and gemcitabine.3. To confirm the relation with the expression of NKX2-1 and EFGR using western-blot.Part III. To detect the expression of serum NKX2-1 in lung cancer patients with ELISA assay.[RESULTS]1. Protein expression:High:NCI-H358, HCC827, A549 and NCI-H446Low:Bease-2B,NCI-H1650, NCI-H1299, NCI-H1993 and SKMES-12. Cell necrosis:NKX2-1 can prompt the necrosis of lung cancer cells in some time.3. Migration:NKX2-1 can inhibit the migration of lung cancer cells and maybe can weaken the metastatic ability in lung cancer.4. Proliferation:NKX2-1 can hold back the proliferation of lung cancer cells in the same time as necrosis.5. The sensitivity to drug: Cisplatin:NKX2-1 has some relationship with cisplatin-resistance. Docetaxel:NKX2-1 also has some relationship with docetaxel-resistance.Gefibinib:NKX2-1 has irrelevant with gefitinib.Gemcitabine:NKX2-1 is susceptible to gemcitabine.6. Correction of Nkx2-1 and EGFR: The total expression of EGFR seemly has nothing to do with Nkx2-1.7. The expression of Nkx2-lwith protein level in lung cancer:The expression of serum Nkx2-1 in lung cancer group is higher than control group. And the level of serum Nkx2-1 with lung cancer patients is no link with the different stage of lung cancer.