XAF1 as a prognostic biomarker and therapeutic target in squamous cell lung cancer

Background X-linked inhibitor of apoptosis （XlAP）-associated factor 1 （XAF1） is a new tumor suppressor. Low expression of XAF1 is associated with poor prognosis of human cancers. However, the effect of XAF1 on lung cancer remains unknown. In this study, we investigated the expression of XAF1 and its role in squamous cell lung cancer. Methods Cancer tissues, cancer adjacent tissues and normal lung tissues were collected from 51 cases of squamous cell lung cancer. The expression of XAF1 mRNA was determined by reverse transcription-polymerase chain reaction （RT-PCR）. The expression of XAF1 protein was determined by Western blotting and immunohistochemical staining. Ad5/F35-XAF1 virus was generated. Cell proliferation and apoptosis were measured by 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide （MTT） method and flow cytometry （FACS）, respectively. Results The levels of XAF1 protein and mRNA in cancer tissues were significantly lower than those in cancer adjacent and normal lung tissues （P 〈0.05）. The low expression of XAF1 was associated with tumor grade, disease stage, differentiation status and lymph node metastasis in squamous cell lung cancer patients. The restoration of XAF1 expression mediated by Ad5/F35-XAF1 virus significantly inhibited cell proliferation and induced apoptosis in a dose- and time-dependent manner. Conclusion XAF1 is a valuable prognostic marker in squamous cell lung cancer and may be a potential candidate gene for lung cancer therapy.

GRP78 upregulation-induced increase in cisplatin sensitivity of SPCA1 lung cancer cells

Background Glucose regulated protein 78 （GRP78）, an endoplasmic reticulum （ER） chaperone, plays a critical role in chemotherapy resistance in a variety of cancers. In this study, we investigated the up-regulation of GRP78 induced by A23187 and its association with the chemotherapeutical sensibility to cisplatin in human lung cancer cell line SPCAI. Methods SPCA1 cells were pretreated with A23187 at different concentrations. The expression of GRP78 at the mRNA level was analyzed by RT-PCR; the expression of GRP78 at the protein level was determined by Western blotting and immunofluorescence assay. Cell survival was determined by MTT assay. Cell apoptosis was analyzed by flow cytometry. Results The expression of GRP78 at both the mRNA and protein levels was obviously induced by A23187 in SPCA1 cells, with an elevation of GRP78 by 2.1-fold at the mRNA level and by 3.8-fold at the protein level compared to the control. There was a dose-dependent response. Survival curve analysis demonstrated that A23187 induction caused a significant reduction of survival for the cells subjected to cisplatin treatment （P 〈0.05）. After treatment by cisplatin, the percentage of apoptotic cells in the A23187 pretreated group increased about three fold compared with the control group （（27.53!-4.32）% vs. （9.25＋3.64）%, P 〈0.05）. Conclusions A23187 treatment was fairly effective for the induction of GRP78 in SPCA1 cells at both the mRNA and protein levels. To a certain extent, GRP78 up-regulation by A23187 was associated with the enhancement of drug sensitivity to cisplatin in human luncl cancer cell line SPCAI.

TGF-β/Akt/Smad signaling regulates ionizing radiation-induced epithelial-mesenchymal transition in acquired radioresistant lung cancer cells

Objective:To define the properties of lung cancer cells that resisted conventionally fractionated radiation exposure.Methods:Acquired radioresistant lung cancer cell line A549 was constructed by X-ray irradiation with a clinical conventional fraction dose of 2 Gy daily during 30 fractions.Cell morphology,molecular markers,migration capacity and invasion potential were evaluated by the microscope,Western blot,immunofluorescence,wound healing test and transwell chamber assay,respectively.Results:Radioresistant A549 cells shifted from an epithelial to a mesenchymal morphology,termed as epithelial-mesenchymal transition(EMT),and was accompanied by decreased expressions of epithelial markers(F=4.568,P<0.05)and increased expression of mesenchymal markers(F=4.270,P<0.05),greater migratory and invasive capabilities(t=6.386,5.644,P<0.05).The expression of TGF-β,and phosphorylated levels of Akt and Smad3 were also enhanced(F=6.496,4.685,3.370,P<0.05).Furthermore,the EMT phenotype induced by radiation could be reversed through inhibition of TGF-β,Akt or Smad3,indicating a functional relationship be-tween them.Conclusions:EMT mediates acquired radioresistance of lung cancer cells induced by IR with clinical parameters,and the crosstalk mode of TGF-β/Akt/Smad signaling plays a critical regulatory role in this process.

THE EFFECTS OF THE ETHANOLIC FRACTION OF CORIOLUS VERSICOLOR ON THE A549 NON-SMALL-CELL LUNG CANCER CELL LINE

Coriolus versicolor has demonstrated anti-cancer effects via polysaccharide-peptides(PSP)and polysaccharide Krestin(PSK).However,many other bioactive compounds within Coriolus versicolor(CV)may not have been identified.Our primary focus was to determine whether the ethanolic extract of Coriolus versicolor demonstrated any anti-cancer effects.The crude ethanolic extract was utilized,as was

Agglutinin isolated from Arisema heterophyllum Blume induces apoptosis and autophagy in A549 cells through inhibiting PI3K/Akt pathway and inducing ER stress

Arisaema heterophyllum Blume is one of the three medicinal plants known as traditional Chinese medicine Rhizoma Arisaematis(RA). RA has been popularly used to treat patients with convulsions, inflammation, and cancer for a long time. However, the underlying mechanisms for RA effects are still unclear. The present study was designed to determine the cytotoxicity of agglutinin isolated from Arisema heterophyllum Blume(AHA) and explore the possible mechanisms in human non-small-cell lung cancer A549 cells. AHA with purity up to 95% was isolated and purified from Arisaema heterophyllum Blume using hydrophobic interaction chromatography. AHA dose-dependently inhibited the proliferation of A549 cells and induced G_1 phase cell cycle arrest. AHA induced apoptosis by up-regulating pro-apoptotic Bax, decreasing anti-apoptotic Bcl-2, and activating caspase-9 and caspase-3. In A549 cells treated with AHA, the PI3K/Akt pathway was inhibited. Furthermore, AHA induced increase in the levels of ER stress markers such as phosphorylated eukaryotic initiation factor 2α(p-eIF2α), C/EBP-homologous protein(CHOP), inositol-requiring enzyme 1α(IRE1α), and phosphorylated c-Jun NH_2-terminal kinase(p-JNK). AHA also induced autophagy in A549 cells. Staining of acidic vesicular organelles(AVOs) and increase in the levels of LC3II and ATG7 were observed in AHA-treated cells. These findings suggested that AHA might be one of the active components with anti-cancer effects in Arisaema heterophyllum Blume. In conclusion, cytotoxicity of AHA on cancer cells might be related to its effects on apoptosis and autophagy through inhibition of PI3K/Akt pathway and induction of ER stress.