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C/EBP homologous protein (CHOP), a 29 kDa cellular protein, plays a role in regulating tumor proliferation, differentiation, metabolism, cell death, and in tumor resistance to chemotherapy. Non-small cell lung cancer (NSCLC) is a tumor of the respiratory system and drug resistance is prevalent among NSCLC clinical cell cultures. Herein, our study elucidated the effect of CHOP on NSCLC cells with cisplatin resistance and its mechanism. In a NSCLC cell line with cisplatin-resistance, CHOP expression was decreased, compared with A549 cells. Overexpression of CHOP decreased the cell viability and enhanced cell apoptosis in the cells treated with cisplatin. Expression of CHOP also inhibited the cell proliferation and metastasis. CHOP increased the therapeutic effect of cisplatin on NSCLC cells through the Bcl-2/JNK pathway. In summary, CHOP regulated cisplatin resistance in cells of NSCLC by promoting the expression of apoptotic proteins and inhibiting the Bcl-2/JNK signaling pathway, indicating the antitumor effects of CHOP.

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BACKGROUND/AIMS: Cigarette smoking is a major risk factor of chronic obstructive pulmonary disease. This study aimed to examine the effects of cigarette smoke extract (CSE) on alveolar type II epithelial cells (AECII) and investigate the underlying mechanism. METHODS: Primary AECII were isolated from rat lung tissues and exposed to CSE. Apoptosis was detected by flow cytometry. Protein expression was detected by Western blot analysis. RESULTS: Primary rat AECII maintained morphological and physiological characteristic after 3 passages. CSE increased the expression of ER specific pro-apoptosis factors CHOP and caspase 12, and the phosphorylation of JNK in AECII. CSE activated ER stress signaling and increased the phosphorylation of PERK, eIF2α and IRE1. Furthermore, CSE induced the expression of Hrd1, a key factor of ER-associated degradation, in AECII. Knockdown of Hrd1 led to more than 2 fold increase of apoptosis, while overexpression of Hrd1 attenuated CSE induced apoptosis of AECII. CONCLUSIONS: Our results suggest that ER stress induces HRD1 to protect alveolar type II epithelial cells from apoptosis induced by CSE.

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OBJECTIVE: To observe the expression of hypoxia-inducible factor-lalpha subunit (HIF-1alpha), HIF prolyl hydroxylase domain-containing protein(PHDs) and factor inhibiting HIF-1(FIH) in pulmonary arteries of patient with chronic obstructive pulmonary disease (COPD). METHODS: Pulmonary specimens were obtained from patients undergoing lobectomy for lung cancer, 12 had concurrent COPD (COPD group) and 14 without COPD (control group). The ratio of vascular wall area to total vascular area (WA%) and pulmonary artery media thickness (PAMT) was observed, and HIF-1alpha and its hydroxylases(PHD1, PHD2, PHD3, FIH) mRNA and protein were detected by in situ hybridization and immunohistochemistry respectively. RESULTS: WA% and PAMT of COPD patients(50 microm +/- 9 microm, 40% +/- 5%, were statistically different from those of the control subjects (39 microm +/- 6 microm, 31% +/- 4%, P < 0.01). Relative quantification of mRNA and protein levels (absorbance, A) showed that HIF-lalpha mRNA and protein levels in COPD group (0.230 +/- 0.036,0.275 +/- 0.039) were statistically higher than those of the control subjects (0.174 +/- 0.029, 0.102 +/- 0.015, P < 0.01 ), and that the protein level increased more markedly. PHD1 mRNA in COPD subjects (0.180 +/- 0.030) was comparable to that in control group (0.191 +/- 0.029, P > 0.05); PHD2 and PHD3 mRNA levels in COPD (0.245 +/- 0.044, 0.252 +/- 0.023) were significantly higher than those in control group(0.182 +/- 0.028, 0.127 +/- 0.017, P < 0.01). On the other hand, in COPD subjects PHD1 protein (0.104 +/- 0.015) was significantly lower(P < 0.01), whereas PHD2 protein (0.274 +/- 0.044) was significantly higher(P < 0.01) than those in control group(0.209 +/- 0.023, 0.219+/- 0.043). As for PHD3 protein, no significant changes were observed between the two groups (0.161+/- 0.023 in COPD, 0.146 +/- 0.021 in control, P > 0.05). FIH mRNA and protein both showed no differences between the two groups. Linear correlation analysis showed that HIF1alpha protein was positively correlated with WA%, PAMT, PHD2 mRNA and protein, PHD3 mRNA, and that HIF1alpha protein was negatively correlated with PHD1 protein. CONCLUSION: PHDs may be involved in the process of hypoxic pulmonary vascular remodeling in COPD via regulation of HIF-1alpha gene expression

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OBJECTIVE: To investigate the expression of mitogen-actived protein kinase (MAPK), phosphatidylinositol 3-kinase (PI3K) and hypoxia-inducible factor-1alpha (HIF-1alpha) in pulmonary artery of chronic obstructive pulmonary disease (COPD), and therefore to explore the possible roles of MAPK, PI3K and HIF-1alpha in the development of hypoxia-induced pulmonary hypertension (HPH). METHODS: Small pulmonary arterial remodeling was observed by morphometric analysis in surgically removed lung tissues from COPD patients and control patients treated for lung tumors. The expression of p-ERK, p-JNK, p-P38, p-PKB and HIF-1alpha in lung tissue was examined by in situ hybridization and immunohistochemistry. RESULTS: Morphometry analysis showed that the ratio of wall area to total area (WA%) and pulmonary artery media thickness (PAMT) were increased in COPD patients [18 +/- 3, (31 +/- 3) microm] than in the control [30 +/- 5, (40 +/- 4) microm, t = 7.58, 6.57, all P < 0.01]. The expression levels of p-ERK protein, p-PKB protein, HIF-1alpha protein and HIF-1alpha mRNA level (absorbance, A) were significantly higher in pulmonary artery walls of COPD patients (0.164 +/- 0.012, 0.113 +/- 0.009, 0.232 +/- 0.008, 0.154 +/- 0.013, respectively) as compared to those of the control (0.062 +/- 0.010, 0.031 +/- 0.011, 0.058 +/- 0.006, 0.052 +/- 0.008, respectively, t = 23.18, 21.03, 62.14, 2.44, all P < 0.01), while p-JNK and p-P38 protein levels in the control group (0.048 +/- 0.013, 0.028 +/- 0.007, respectively) and COPD patients (0.041 +/- 0.012, 0.031 +/- 0.010, respectively, all P > 0.05) were barely positive. The expression of p-ERK, p-PKB and HIF-1alpha were negatively correlated with LA% (r = -0.920 - -0.892, all P < 0.05), and positively correlated with PAMT (r = 0.895 - 0.934, all P < 0.05). CONCLUSION: Differential expression of p-ERK, p-PKB and HIF-1alpha may be involved in the occurrence of HPH in COPD patients.

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OBJECTIVE: To investigate the dynamic expression of hypoxia-inducible factor 1alpha (HIF-1alpha) and mitogen-activated protein kinase (MAPK) in pulmonary arteries of rats with hypoxia-induced pulmonary hypertension. METHODS: Forty male adult Wistar rats were randomly divided into five groups:a control group (C group) and groups with hypoxia for 3, 7, 14 and 21 days (H(3), H(7), H(14) and H(21) group), eight rats per group. Mean pulmonary pressure (mPAP), right ventrical hypertrophy index (RVHI) and vessel morphometry were measured. The levels of HIF-1alpha mRNA expression in lung tissue was measured by in site hybridization (ISH). The protein expression of HIF-1alpha and p-ERK, p-JNK, p-P38 were observed by immunohistochemistry or Western blot. RESULTS: The level of mPAP [(23.5 +/- 1.8) mm Hg], the ratio of vascular wall thickness to external diameter [WT, (45.5 +/- 3.1)%] and the ratio of vascular wall area to the total area [LA, (54.7 +/- 3.2)%] were significantly higher in H(7) group than those in C group [(16.2 +/- 2.0) mm Hg, (36.8 +/- 2.5)% and (63.2 +/- 2.5)% respectively, all P < 0.05]. These parameters reached a high level and remained stable on H(14) group, RVHI was significantly higher [(26.9 +/- 1.3)%] on H(14) group than in C group [(23.0 +/- 1.5)%, P < 0.05]. Expression of p-ERK protein in C group was barely positive, but was up-regulated in pulmonary arterial tunica intima and tunica media of all hypoxia rats. Expression of p-JNK and p-P38 in C group and hypoxia groups were barely positive. Expression of HIF-1alpha protein in C group was barely positive, but was up-regulated in pulmonary arterial tunica intima of all hypoxic rats. In pulmonary arterial tunica media, the levels of HIF-1alpha protein was markedly up-regulated in H(3) group (0.209 +/- 0.009, P < 0.05), reaching its peak at H(7) group (0.232 +/- 0.008, P < 0.05), then tended to decline in H(14) group and H(21) group. HIF-1alpha mRNA staining was barely positive in C group, H(3) group and H(7) group, but began to increase significantly at H(14) group (0.305 +/- 0.104, P < 0.05), then remained stable in pulmonary arterial tunica intima. Linear correlation analysis showed that p-ERK, HIF-1alpha mRNA and mPAP were correlated with vessel morphometry and RVHI (P < 0.01); p-ERK was positively correlated with HIF-1alpha mRNA and protein (tunica intima). CONCLUSION: MAPK as a signal transduction may play an important role in the development of hypoxia-induced pulmonary hypertension.

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