Suppression of AKT expression by miR‐153 produced anti‐tumor activity in lung cancer

Lung cancer is one of the leading causes of cancer death worldwide. microRNAs have been shown to be a novel class of regulators in lung cancer. Here, we explored the role of miR‐153 in the pathogenesis of lung cancer and its therapeutic potential. miR‐153 was significantly decreased in lung cancer tissues than the adjacent tissues. The protein and mRNA levels of protein kinase B (AKT), which were shown to promote tumor growth, were both increased in lung cancer tissues than adjacent tissues. Overexpression of miR‐153 significantly inhibited AKT protein expression, which were abrogated by co‐transfection of AMO‐153, the specific inhibitor of miR‐153. Luciferase assay showed that transfection of miR‐153 markedly suppressed the fluorescent intensity of chimeric vectors carrying the 3'UTR of AKT1, while produced no effect on the mutant construct, indicating that AKT is regulated by miR‐153. Overexpression of miR‐153 significantly inhibited the proliferation and migration, and promoted apoptosis of cultured lung cancer cells in vitro, and suppressed the growth of xenograft tumors in vivo. Interestingly, lung cancer cells with lower endogenous miR‐153 expression are more sensitive to ectopic overexpressed miR‐153. The IC₅₀ of miR‐153 on lung cancer cells is positive correlated with the endogenous miR‐153 level, while negative correlated with AKT level. Knockdown of AKT expression suppressed lung cancer cell proliferation. In summary, miR‐153 exerted anti‐tumor activity in lung cancer by targeting on AKT. The sensitivity of lung cancer cells to miR‐153 is determined by its endogenous miR‐153 level.     

Targeting SLC1a5‐mediated glutamine dependence in non‐small cell lung cancer

We previously elucidated the pleotropic role of solute carrier family A1 member 5 (SLC1A5) as the primary transporter of glutamine (Gln), a modulator of cell growth and oxidative stress in non‐small cell lung cancer (NSCLC). The aim of our study was to evaluate SLC1A5 as a potential new therapeutic target and candidate biomarker predictive of survival and response to therapy. SLC1A5 targeting was examined in a panel of NSCLC and human bronchial cell lines by RNA interference and by a small molecular inhibitor, gamma‐l ‐glutamyl‐p‐nitroanilide (GPNA). The effects of targeting SLC1A5 on cell growth, Gln uptake, ATP level, autophagy and cell death were examined. Inactivation of SLC1A5 genetically or pharmacologically decreased Gln consumption, inhibited cell growth, induced autophagy and apoptosis in a subgroup of NSCLC cell lines that overexpress SLC1A5. Targeting SLC1A5 function decreased tumor growth in NSCLC xenografts. A multivariate Cox proportional hazards analysis indicates that patients with increased SLC1A5 mRNA expression have significantly shorter overall survival (p = 0.01, HR = 1.24, 95% CI: 1.05–1.46), adjusted for age, gender, smoking history and disease stage. In an immunohistochemistry study on 207 NSCLC patients, SLC1A5 protein expression remained highly significant prognostic value in both univariate (p < 0.0001, HR = 1.45, 95% CI: 1.15–1.50) and multivariate analyses (p = 0.04, HR = 1.22, 95% CI: 1.01–1.31). These results position SLC1A5 as a new candidate prognostic biomarker for selective targeting of Gln‐dependent NSCLC.     

Long noncoding RNA actin filament‐associated protein 1 antisense RNA 1 promotes malignant phenotype through binding with lysine‐specific demethylase 1 and repressing HMG box‐containing protein 1 in non‐small‐cell lung cancer

The number of documented long noncoding RNAs (lncRNAs) has dramatically increased, and their biological functions and underlying mechanisms in pathological processes, especially cancer, remain to be elucidated. Actin filament‐associated protein 1 antisense RNA 1 (AFAP1‐AS1) is a 6810‐nt lncRNA located on chromosome 4p16.1 that was first reported to be upregulated in esophageal adenocarcinoma tissues and cell lines. Here we reported that AFAP1‐AS1, recruiting and binding to lysine‐specific demethylase 1 (LSD1), was generally overexpressed in human non‐small‐cell lung cancer (NSCLC) tissues using quantitative real‐time PCR. Higher AFAP1‐AS1 expression was significantly correlated with larger tumor size (P = .008), lymph node metastasis (P = .025), higher TNM stage (P = .024), and worse overall survival in NSCLC patients. In vitro experiments revealed that AFAP1‐AS1 downregulation inhibited cell migration and induced apoptosis; AFAP1‐AS1 knockdown also hindered tumorigenesis in vivo. Moreover, mechanistic investigations including RNA immunoprecipitation and ChIP assays validated that AFAP1‐AS1 repressed HMG box‐containing protein 1 (HBP1) expression by recruiting LSD1 to the HBP1 promoter regions in PC‐9 and H1975 cells. Furthermore, HBP1 functions as a tumor suppressor, and its ectopic expression hindered cell proliferation. Rescue assays determined that the oncogenic effect of AFAP1‐AS1 is partially dependent on the epigenetic silencing of HBP1. In conclusion, our results indicate that AFAP1‐AS1 is carcinogenic and that the AFAP1‐AS1/LSD1/HBP1 axis could constitute a new therapeutic direction for NSCLC.     

The sphingosine kinase 2 inhibitor ABC294640 displays anti‐non‐small cell lung cancer activities in vitro and in vivo

Non‐small cell lung cancer (NSCLC) accounts for about 85‐90% of lung cancer cases, and is the number one killer among cancers in the United States. The majorities of lung cancer patients do not respond well to conventional chemo‐ and/or radio‐therapeutic regimens, and have a dismal 5‐year survival rate of ～15%. The recent introduction of targeted therapy and immunotherapy gives new hopes to NSCLC patients, but even with these agents, not all patients respond, and responses are rarely complete. Thus, there is still an urgent need to identify new therapeutic targets in NSCLC and develop novel anti‐cancer agents. Sphingosine kinase 2 (SphK2) is one of the key enzymes in sphingolipid metabolism. SphK2 expression predicts poor survival in NSCLC patients, and is associated with Gefitinib‐resistance. In this study, the anti‐NSCLC activities of ABC294640, the only first‐in‐class orally available inhibitor of SphK2, were explored. The results obtained indicate that ABC294640 treatment causes significant NSCLC cell apoptosis, cell cycle arrest and suppression of tumor growth in vitro and in vivo. Moreover, lipidomics analyses revealed the complete signature of ceramide and dihydro(dh)‐ceramide species in the NSCLC cell‐lines with or without ABC294640 treatment. These findings indicate that sphingolipid metabolism targeted therapy may be developed as a promising strategy against NSCLC.     

Long non‐coding RNA UCA1 promotes glycolysis by upregulating hexokinase 2 through the mTOR–STAT3/microRNA143 pathway

Cancer cells preferentially metabolize glucose through aerobic glycolysis, a phenomenon known as the Warburg effect. Emerging evidence has shown that long non‐coding RNAs (lncRNAs) act as key regulators of multiple cancers. However, it remains largely unexplored whether and how lncRNA regulates glucose metabolism in cancer cells. In this study, we show that lncRNA UCA1 promotes glycolysis in bladder cancer cells, and that UCA1‐induced hexokinase 2 (HK2) functions as an important mediator in this process. We further show that UCA1 activates mTOR to regulate HK2 through both activation of STAT3 and repression of microRNA143. Taken together, these findings provide the first evidence that UCA1 plays a positive role in cancer cell glucose metabolism through the cascade of mTOR–STAT3/microRNA143–HK2, and reveal a novel link between lncRNA and the altered glucose metabolism in cancer cells.     

Prolonged survival after resection and radiotherapy for solitary brain metastases from non‐small‐cell lung cancer

Selected patients with brain metastases from non‐small‐cell lung cancer benefit from aggressive treatment. This report describes three patients who developed solitary brain metastases after previous resection of primary adenocarcinoma of the lung. Each underwent surgical resection of their brain metastasis followed by cranial irradiation and remain disease free 10 or more years later. Two patients developed cognitive impairment approximately 8 years after treatment of their brain metastasis, which was felt to be due to their previous brain irradiation. Here we discuss the treatment of solitary brain metastasis, particularly the value of combined method approaches in selected patients and dose–volume considerations.     

Genetic variation in innate immunity and inflammation pathways associated with lung cancer risk

BACKGROUND:

Pulmonary inflammation may contribute to lung cancer etiology. The authors conducted a broad evaluation of the association of single nucleotide polymorphisms (SNPs) in innate immunity and inflammation pathways with lung cancer risk and conducted comparisons with a lung cancer genome‐wide association study (GWAS).

METHODS:

In total, 378 patients with lung cancer (cases) and a group of 450 controls from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial were included. A proprietary oligonucleotide pool assay was used to genotype 1429 SNPs. Odds ratios and 95% confidence intervals were estimated for each SNP, and P values for trend (P_trend) were calculated. For statistically significant SNPs (P_trend < .05), the results were replicated with genotyped or imputed SNPs in the GWAS, and P values were adjusted for multiple testing.

RESULTS:

In the PLCO analysis, a significant association was observed between lung cancer and 81 SNPs located in 44 genes (P_trend < .05). Of these 81 SNPS, there was evidence for confirmation in the GWAS for 10 SNPs. However, after adjusting for multiple comparisons, the only SNP that retained a significant association with lung cancer in the replication phase was reference SNP rs4648127 (nuclear factor of kappa light polypeptide gene enhancer of B‐cells 1 [NFKB1]) (multiple testing‐adjusted P_trend = .02). The cytosine‐thymine (CT)/TT genotype of NFKB1 was associated with reduced odds of lung cancer in the PLCO study (odds ratio, 0.56; 95% confidence interval, 0.37‐0.86) and the in the GWAS (odds ratio, 0.79; 95% confidence interval, 0.69‐0.90).

CONCLUSIONS:

A significant association was observed between a variant in the NFKB1 gene and the risk of lung cancer. The current findings add to evidence implicating inflammation and immunity in lung cancer etiology. Cancer 2012. Published 2012 by the American Cancer Society.     

Polymorphisms of EpCAM gene and prognosis for non‐small‐cell lung cancer in Han Chinese

The epithelial cell adhesion molecule (EpCAM) is overexpressed in a wide variety of human cancers and is associated with patient prognosis, including those with lung cancer. However, the association of single nucleotide polymorphisms (SNPs) in the EpCAM gene with the prognosis for non‐small‐cell lung cancer (NSCLC) patients has never been investigated. We evaluated the association between two SNPs, rs1126497 and rs1421, in the EpCAM gene and clinical outcomes in a Chinese cohort of 506 NSCLC patients. The SNPs were genotyped using the Sequenom iPLEX genotyping system. Multivariate Cox proportional hazards model and Kaplan–Meier curves were used to assess the association of EpCAM gene genotypes with the prognosis of NSCLC. We found that the non‐synonymous SNP rs1126497 was significantly associated with survival. Compared with the CC genotype, the CT+TT genotype was a risk factor for both death (hazard ratio, 1.40; 95% confidence interval [CI], 1.02–1.94; P = 0.040) and recurrence (hazard ratio, 1.34; 95% CI, 1.02–1.77; P = 0.039). However, the SNP rs1421 did not show any significant effect on patient prognosis. Instead, the AG+GG genotype in rs1421 was significantly associated with early T stages (T1/T2) when compared with the AA genotype (odds ratio for late stage = 0.65; 95% CI, 0.44–0.96, P = 0.029). Further stratified analysis showed notable modulating effects of clinical characteristics on the associations between variant genotypes of rs1126497 and NSCLC outcomes. In conclusion, our study indicated that the non‐synonymous SNP rs1126497 may be a potential prognostic marker for NSCLC patients.     

Whole blood FPR1 mRNA expression predicts both non‐small cell and small cell lung cancer

While long‐term survival rates for early‐stage lung cancer are high, most cases are diagnosed in later stages that can negatively impact survival rates. We aim to design a simple, single biomarker blood test for early‐stage lung cancer that is robust to preclinical variables and can be readily implemented in the clinic. Whole blood was collected in PAXgene tubes from a training set of 29 patients, and a validation set of 260 patients, of which samples from 58 patients were prospectively collected in a clinical trial specifically for our study. After RNA was extracted, the expressions of FPR1 and a reference gene were quantified by an automated one‐step Taqman RT‐PCR assay. Elevated levels of FPR1 mRNA in whole blood predicted lung cancer status with a sensitivity of 55% and a specificity of 87% on all validation specimens. The prospectively collected specimens had a significantly higher 68% sensitivity and 89% specificity. Results from patients with benign nodules were similar to healthy volunteers. No meaningful correlation was present between our test results and any clinical characteristic other than lung cancer diagnosis. FPR1 mRNA levels in whole blood can predict the presence of lung cancer. Using this as a reflex test for positive lung cancer screening computed tomography scans has the potential to increase the positive predictive value. This marker can be easily measured in an automated process utilizing off‐the‐shelf equipment and reagents. Further work is justified to explain the source of this biomarker.