Endothelial cell (EC) apoptosis contributes to cigarette smoke (CS)-induced pulmonary emphysema. Metabolism of glucose, glutamine, and fatty acid is dysregulated in patients with chronic obstructive pulmonary disease (COPD). Whether CS causes metabolic dysregulation in ECs leading to development of COPD remains elusive. We hypothesized that CS alters metabolism, resulting in apoptosis in lung ECs. To test this hypothesis, we treated primary mouse pulmonary microvascular ECs (PMVECs) with CS extract (CSE) and employed PMVECs from healthy subjects and COPD patients. We found that mitochondrial respiration was reduced in CSE-treated PMVECs and in PMVECs from COPD patients. Specifically, oxidation of fatty acids (FAO) was reduced in these cells, which linked to reduced carnitine palmitoyltransferase 1a (Cpt1a), an essential enzyme for carnitine shuttle. CSE-induced apoptosis was further increased when cells were treated with a specific Cpt1 inhibitor etomoxir or transfected with Cpt1a siRNA. L-Carnitine treatment augmented FAO but attenuated CSE-induced apoptosis by upregulating Cpt1a. CSE treatment increased palmitate-derived ceramide synthesis, which was reduced by L-carnitine. Although CSE treatment increased glycolysis, inhibiting glycolysis with 2-deoxy-d-glucose had no effects on CSE-mediated apoptosis in lung ECs. Conclusively, FAO reduction increases ceramide and apoptosis in lung ECs treated with CSE, which may contribute to the pathogenesis of COPD/emphysema.

Chromatin assembly factor 1 subunit A (CHAF1A) is the largest subunit of the chromatin assembly factor 1 (CAF-1) complex that is implicated in the assembly of nucleosomes on newly synthesized DNA. The aim of the present study was to determine its expression and biological function in non-small cell lung cancer (NSCLC). The current study examined the levels of CHAF1A expression in 22 samples of NSCLC and corresponding normal lung tissues. Subsequently, endogenous CHAF1A expression in H1299 NSCLC cells was knocked down via lentiviral delivery of CHAF1A-targeting short hairpin RNA (shRNA), and cell proliferation, colony formation and cell cycle distribution were measured. The results demonstrated that levels of CHAF1A mRNA level were ~3-fold greater in NSCLC samples compared with adjacent normal tissues (P<0.05). shRNA-mediated silencing of CHAF1A significantly inhibited the proliferation and colony formation of H1299 cells, compared wirh the delivery of control shRNA (P<0.05). Furthermore, CHAF1A shRNA-transduced cells exhibited a significant increase in the percentage of S-phase cells and a significant decrease in the percentage of cells at the G0/G1 and G2/M phases, compared with control cells (P<0.05). Additionally, CHAF1A knockdown significantly decreased the expression of cyclin D1, cyclin-dependent kinase 2 and S-phase kinase-associated protein 2, and increased the expression of p21 and p27. This indicates that CHAF1A is upregulated in NSCLC and that its silencing suppresses the proliferation and colony formation of NSCLC cells, potentially by inducing G0/G1 cell cycle arrest. CHAF1A may therefore represent a potential therapeutic target to treat NSCLC.

Chromatin assembly factor 1 subunit B (CHAF1B) participates in DNA synthesis and repair. High CHAF1B expression has been associated with a poor prognosis in several types of cancers. However, no study has evaluated the clinical significance and biological function of CHAF1B in non-small cell lung cancer (NSCLC). In the present study, we aimed to investigate CHAF1B expression and its role in NSCLC. In the present study, it was revealed that CHAF1B was highly expressed in NSCLC lung tissues and 95-D cells. Kaplan-Meier survival analysis indicated that high CHAF1B expression in tumour tissue was associated with poor clinical outcomes in NSCLC patients. Multivariate Cox analyses revealed that lymph node metastasis, tumour-node-metastasis (TNM) stage and CHAF1B expression were independent prognostic factors in NSCLC patients. Moreover, CHAF1B knockdown in 95-D cells markedly inhibited tumour proliferation, reduced colony formation, induced cell cycle arrest and promoted apoptosis. In vivo studies demonstrated that CHAF1B knockdown inhibited the growth of transplanted tumours. Furthermore, our results revealed that the mechanism by which CHAF1B induced apoptosis was mediated by the activation of the p53-dependent apoptotic signalling pathway (BAK/Bcl-2/caspase-3) in 95-D cells. These data indicated that CHAF1B plays an important role in tumourigenesis and may be a therapeutic molecular target to counter NSCLC progression.

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The aim of this study was to investigate the role of chromatin assembly factor 1 subunit A (CHAF1A) in the pathogenesis of non-small cell lung cancer (NSCLC), as well as its association with disease prognosis. The expression levels of CHAF1A in NSCLC tissues were detected by immunohistochemical staining. The relationship between CHAF1A and patient survival was analysed. The effects of CHAF1A knock-down on cell proliferation, cell cycle, cell clones and cellular apoptosis were also analysed. The results showed that CHAF1A staining was observed in the cell nuclei in the NSCLC tissue, with higher H-score. In the CHAF1A low-expression group, the 5year survival rate was significantly higher and the recurrence rate was significantly lower compared with the high-expression group. Tumour size, lymph node metastasis, clinical staging and H-score represented influencing factors related to the 5-year survival. CHAF1A expression was significantly associated with the 5-year overall survival and metastasis and recurrence of NSCLC. In addition, CHAF1A knock-down inhibited the proliferation and changed the cell cycles, cell clones and cellular apoptosis in the lung cancer cells. The results indicated that higher CHAF1A expression is related to shortened survival period of NSCLC, and CHAF1A knock-down inhibited the proliferation of lung cancer cell lines. CHAF1A might represent a disease prognostic predictor in clinic.