The prognostic value of osteopontin expression in non-small cell lung cancer: a meta-analysis

Prognostic and clinicopathological value of osteopontin expression in non-small cell lung cancer: a meta-analysis and systematic review

BACKGROUND

Although Osteopontin (OPN) has been reported to be associated with many different human cancers, the data on non-small cell lung cancer (NSCLC) are not definitive. This study aimed to explore the prognostic effect of OPN expression and clinicopathological characteristics in patients with NSCLC.

METHODS

This study followed all aspects of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) report. PubMed, Embase and the Cochrane Library were searched to identify the relative studies. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to estimate the prognostic value of the OPN in patients with NSCLC. The odds ratio (OR) was calculated to represent the relationship between OPN expression and clinicopathological parameters.

RESULTS

A total of fifteen studies with 2173 participants were finally included. The results revealed that high expression of OPN was significantly associated with poorer overall survival (OS) (HR = 1.89; 95%CI = 1.68-2.11; p < 0.001). Moreover, a significant correlation was observed between increased OPN expression and poorly differentiated (well and moderately differentiated vs. poorly differentiated; pooled OR = 0.38; 95% CI = 0.23-0.64; p < 0.001), lymph node metastasis (absence vs. presence; pooled OR = 0.49; 95%CI = 0.32-0.74; p < 0.001), and distant metastasis (absence vs. presence; pooled OR = 0.18; 95%CI = 0.11-0.29; p < 0.001).

CONCLUSION

This meta-analysis implies that OPN might be a valuable biomarker for a poor prognosis and poor clinicopathological outcomes for patients with NSCLC.

HAX1 enhances the survival and metastasis of non-small cell lung cancer through the AKT/mTOR and MDM2/p53 signaling pathway

Background

HS‐1‐associated protein‐1 (HAX1) has been reported to be overexpressed in non‐small cell lung cancer (NSCLC) tissues. However, the underlying mechanism of HAX1 in NSCLC has not previously been demonstrated. The present study investigated the role and underlying mechanism of HAX1 in NSCLC.

Methods

The HAX1 expression were confirmed in NSCLC tissues through TCGA database and qRT‐PCR. Moreover, we performed qRT‐PCR, Western blotting, Transwell assays, TUNEL assays and so on to evaluate the role of HAX1 in A549 and H1299 cell lines.

Results

mRNA expression of HAX1 was overexpressed in NSCLC tissues compared to adjacent normal tissues according to The Cancer Genome Atlas (TCGA) database. QRT‐PCR assays showed that HAX1 mRNA expression was upregulated in NSCLC tissues. The high HAX1 mRNA levels were found to be positively associated with tumor size, TNM stage and lymphatic metastasis. Silencing of HAX1 promoted apoptosis and reduced invasion of A549 and H1299 cells by inhibiting the AKT/mTOR and MDM2/P53 signal pathway. AKT agonist SC79 could inhibit apoptosis and promote proliferation, migration and invasion of A549 and H1299 cells transfected with si‐HAX1.

Conclusions

The present study provided a better understanding of HAX1 mechanism in NSCLC and potential therapeutic target for NSCLC.

Blood serum proteins as biomarkers for prediction of survival, locoregional control and distant metastasis rate in radiotherapy and radio-chemotherapy for non-small cell lung cancer

BACKGROUND

Several studies have documented that blood biomarkers can improve basic prognostic models in radiotherapy and radio-chemotherapy for non-small cell lung cancer. The current study evaluated the prognostic impact of six markers focusing on their utility in homogenous subsets, compared to the significance in a large heterogeneous group.

METHODS

Blood samples of 337 patients who were referred for curative or palliative external beam thoracic radiotherapy for non-small cell lung cancer were collected. The concentration of osteopontin (OPN), vascular endothelial growth factor (VEGF), erythropoetin (EPO), high mobility group box 1 protein (HMGB1), insulin-like growth factor 1 (IGF-1) and platelet-derived growth factor (PDGF) in serum were measured by ELISA assay and the prognostic potential was assessed using univariable and multivariable survival models.

RESULTS

Multivariable analysis revealed that out of several variables studied six dichotomized features: namely: cigarette smoking, lack of chemotherapy, palliative doses of radiotherapy, high OPN concentration, advanced T stage and high VEGF concentration had a highly significant (p < 0.005) and independent influence on overall survival in the group of 337 patients. In a subset of patients treated with curative radio-chemotherapy or radiotherapy (N = 148) tumor pathology, EPO concentration and VEGF concentration, significantly and independently influenced overall survival. In a subset of patients with squamous cell cancer (N = 206) OPN had a highly significant impact on overall survival. In contrast, in a subset of patients with nonsquamous histology (N = 131) only VEGF had a significant influence on survival.

CONCLUSIONS

Blood serum proteins appear to be clinically useful prognosticators of overall survival in radio-chemotherapy and radiotherapy for non-small cell lung cancer. In unselected heterogeneous groups, dichotomized concentrations of OPN and VEGF emerged among the strongest independent prognosticators of overall survival. VEGF and EPO concentration (dichotomized) were found to be independent prognostic factors among the patients treated with curative doses of radiotherapy. The utility of OPN as a prognostic marker appeared restricted to the patients with squamous histology.

Osteopontin promotes cancer cell drug resistance, invasion, and lactate production and is associated with poor outcome of patients with advanced non-small-cell lung cancer

Background

Osteopontin (OPN), a member of the small integrin binding ligand N-linked glycoprotein family, has been analyzed in numerous types of human malignancy.

Purpose

The present study detected the expression levels of OPN and evaluated its role in tumor progression in patients with non-small cell lung cancer (NSCLC).

Patients and methods

OPN expression levels were detected using immunohistochemistry in 101 NSCLC tumors. The mRNA and protein levels have significant difference between advanced NSCLC and stage I/II NSCLC. The drug resistance, invasive ability and lactate production of NSCLC cancer cell lines (A549 and SK-MES-1) were detected in cancer cells with the disturbance of OPN.

Results

Immunostaining indicated that OPN was primarily expressed in the cytoplasm of NSCLC cells. Moreover, OPN correlates with NSCLC clinical traits. The results demonstrated that OPN expression levels significantly correlated with cancer differentiation, distant metastasis and the efficacy of platinum-based treatment. Notably, the results identified OPN expression levels as a potential factor for predicting the response of cells to first-line platinum-based chemotherapy using multivariate analysis, as well as predicting cancer differentiation and distant metastasis. Additionally, the abrogation of OPN levels reduced lactate production in NSCLC cells and occurred along side with the downregulation of lactate dehydrogenase A (LDHA).

Conclusion

The results of the current study suggest that OPN may be able to predict poor prognosis and cisplatin resistance in patients.

miR-335 inhibited cell proliferation of lung cancer cells by target Tra2β

Accumulating evidence has suggested that the dysregulation of miRNA is an important factor in the pathogenesis of lung cancer. Here, we demonstrate that miR-335 expression is reduced in non-small cell lung cancer (NSCLC) tumors relative to non-cancerous adjacent tissues, while the expression of Tra2β is increased. In addition, clinical data revealed that the increased Tra2β and decreased miR-335 expression observed in NSCLC cells was associated with poor patient survival rates. In vitro experimentation showed that the overexpression of miR-335 inhibited the growth, invasion and migration capabilities of A459 lung cancer cells, by targeting Tra2β. In contrast, inhibition of miR-335 or overexpression of the Tra2β target gene stimulated the growth, invasion and migratory capabilities of A459 lung cancer cells in vitro. Furthermore, overexpression of miR-335 or inhibition of Tra2β decreased the phosphorylation of Rb-S780 and Rb-AKT. Overall, these findings suggest that the downregulation of miR-335 in A459 lung cancer cells promoted cell proliferation through upregulation of Tra2β, mediated via activation of the AKT/mTOR signaling pathway, and suggest that miR-335 may have potential as a novel therapeutic target for NSCLC.

Decreased expression of speckle-type POZ protein for the prediction of poor prognosis in patients with non-small cell lung cancer

Speckle-type POZ domain protein (SPOP) has been acknowledged as a tumor suppressor gene in numerous types of cancer. However, SPOP expression and its prognostic role in human non-small cell lung cancer (NSCLC) remain unknown. The present study investigated SPOP expression in NSCLC and evaluated its prognostic significance in patients with NSCLC. The results demonstrated that SPOP expression was significantly downregulated in NSCLC tissues at the mRNA and protein level compared with normal lung tissues using reverse transcription-quantitative polymerase chain reaction, and western blot analysis. Immunohistochemical staining results also demonstrated that SPOP was expressed at a low level in 84.1% (132/157) of NSCLC samples and at a high level in 52.2% (12/23) of normal lung samples, whereby the difference was statistically significant (P<0.001). In addition, it was revealed that the level of SPOP was associated with histologic type (P=0.003), tumor differentiation (P=0.046), tumor size (P=0.0036), lymph node metastasis (P=0.041) and clinical stages (P=0.046). Furthermore, the overall survival of patients with high SPOP expression was significantly increased compared with that of patients with low SPOP expression (P=0.003). These results revealed that SPOP expression was downregulated in NSCLC tissues and associated with poor prognosis in patients with NSCLC, suggesting that SPOP is an independent prognostic marker candidate for NSCLC.

miR-202 functions as a tumor suppressor in non-small cell lung cancer by targeting STAT3

MicroRNAs (miRNAs) are a group of non-protein‑coding, short single-stranded RNAs, which are considered as promising molecular markers and therapeutic targets in several cancers. The present study explored the expression patterns and functional roles of miR‑202 in non‑small cell lung cancer (NSCLC). The expression levels of miR‑202 were determined in NSCLC tissues and cell lines using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). The functional impact of miR‑202 overexpression on NSCLC cell viability, migration and invasion were evaluated using Cell Counting Kit‑8 reagent and Transwell migration and invasion assays, respectively. The molecular mechanism underlying the tumor suppressive roles of miR‑202 on NSCLC was examined using bioinformatics analysis, luciferase reporter assay, RT‑qPCR and western blot analysis. In addition, signal transducer and activator of transcription (STAT) 3 was overexpressed to investigate the impact on miR‑202‑mediated tumor suppression in NSCLC. The results indicated that miR‑202 was downregulated in NSCLC tissues and cell lines, and was associated with tumor node metastasis stage and lymph node metastasis. Exogenous miR‑202 expression reduced NSCLC cell viability, migration and invasion. Furthermore, STAT3 was identified as a direct target gene of miR‑202 in NSCLC. STAT3 overexpression improved miR‑202‑impaired cell viability, migration and invasion. In conclusion, the present study revealed novel anticancer effects induced by miR‑202 upregulation in NSCLC, and indicated that STAT3 may be a molecular target of miR‑202.

MicroRNA-29a functions as a potential tumor suppressor through directly targeting CDC42 in non-small cell lung cancer

The expression and function of microRNA-29a (miR-29a) have been investigated in various types of cancer. In the present study, the expression, function and underlying molecular mechanism of miR-29a were investigated in non-small cell lung cancer (NSCLC). The expression level of miR-29a in NSCLC was determined using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell proliferation, migration and invasion ability were determined using Cell Counting Kit-8, cell migration and invasion assays, respectively. Bioinformatics analysis and dual-luciferase reporter assays were performed to determine whether cell division cycle 42 (CDC42) is a direct target gene of miR-29a. To assess CDC42 mRNA and protein expression following transfection with miR-29a, RT-qPCR and western blotting were performed. Following knockdown of CDC42, functional assays were performed to investigate the roles of CDC42 in NSCLC. The results demonstrated that miR-29a was downregulated in NSCLC and the decreased expression level of miR-29a was significantly associated with advanced tumor-node-metastasis classification and metastasis. In addition, upregulation of miR-29a inhibited cell proliferation, migration and invasion in NSCLC, whereas downregulation of miR-29a had the opposite effects. Furthermore, CDC42 was identified as a direct target gene of miR-29a in vitro. miR-29a was demonstrated to function as a tumor suppressor in NSCLC by directly targeting CDC42 and may be investigated further as a target therapy for NSCLC.

Loss of phosphatase and tensin homolog expression correlates with clinicopathological features of non-small cell lung cancer patients and its impact on survival: A systematic review and meta-analysis

BACKGROUND

Phosphatase and tensin homolog ( PTEN ), regarded as a tumor suppressor gene, may act as a prognostic biomarker in human cancers.

METHODS

All eligible studies from MEDLINE, Embase, CENTRAL, and the Chinese BioMedical Literature Database to October 2016 were incorporated. Two reviewers independently screened the literature according to inclusion and exclusion criteria, extracted the data, assessed the methodological quality of the included studies, and conducted meta-analysis.

RESULTS

A total of 2486 patients from 19 studies were included. PTEN expression was significantly correlated with gender, smoking history, histology (adenocarcinoma [ADC] vs. squamous cell carcinoma), tumor node metastasis stage (I-II vs. III-IV), N status (N0 vs. N1-N3), and distant metastasis (M0 vs. M1). Loss of PTEN expression was associated with poorer overall survival, but had no significant association with disease-free survival. Subgroup analysis showed that negative PTEN expression was associated with a poorer outcome in Asian and ADC patients, but not in Western or squamous cell carcinoma patients.

CONCLUSION

Loss of PTEN might play an unfavorable prognostic role for overall survival of non-small cell lung cancer patients, especially Asian or ADC patients.

MicroRNA-320 was downregulated in non-small cell lung cancer and inhibited cell proliferation, migration and invasion by targeting fatty acid synthase

The expression and functions of microRNA (miR)-320 have been previously investigated in various types of cancer. However, to the best of our knowledge, no previous studies have investigated miR-320 in human lung cancer. The current study determined the expression, biological functions and molecular mechanisms of miR‑320 in human lung cancer. The expression level of miR‑320 in human non‑small cell lung cancer (NSCLC) and normal adjacent tissue samples (NATs), NSCLC cell lines and non‑tumorigenic bronchial epithelial cells was measured by reverse transcription‑quantitative polymerase chain reaction. Following transfection with miR‑320 mimics, 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide, cell migration and cell invasion assays, western blot analysis and luciferase assay were performed in human NSCLC cell lines. The results demonstrated that miR‑320 was significantly downregulated in NSCLC tissue samples and cell lines compared with NATs and a control cell line, respectively. Statistical analysis demonstrated that expression of miR‑320 was significantly associated with the TNM classification and metastasis. It was also observed that miR‑320 inhibited cell growth, migration and invasion in NSCLC cells. Additionally, the present study provided evidence that miR‑320 may directly target fatty acid synthase. These results suggest that miR‑320 may serve as a therapeutic biomarker of NSCLC in the future.

Selective expression of transthyretin in subtypes of lung cancer

Transthyretin (TTR) is expressed primarily in liver, choroid plexus of brain and pancreatic islet A and B cells. It is also synthesized in some endocrine tumors. In the present study, the protein expression of TTR in lung cancer tissues and cell lines was investigated by western blot. The mRNA expression of TTR in 24 pairs of frozen lung cancer tissues was examined by RT-PCR. The specific expression and cellular distribution of TTR were also evaluated in 104 paraffin-embedded lung cancer samples and 3 normal lung tissues by immunohistochemistry. Similarly, the subcellular localization and expression of TTR were further analyzed in lung cancer cell lines. With the exception of mucinous adenocarcinoma, the expression of TTR protein was observed in all tested subtypes of lung carcinoma. Adenocarcinoma displayed the highest positive expression rate of TTR, accounting for 84.4 %, and the positive expression rate of TTR was up to 85.7 % at stages III and IV. The secretory bubbles with strong TTR staining were observed in luminal cells of lung cancer. Furthermore, the localization of TTR in the cytoplasm of lung cancer cells and the secretion of TTR into extracellular milieu were also confirmed. Taken together, TTR is selectively synthesized in lung cancer cells and can be secreted extracellularly.

Correlation between lung neoplasm and serum level of osteopontin: A meta-analysis

The aim of this meta-analysis was to evaluate the clinical significance of serum osteopontin (OPN) levels in lung neoplasm in patients to establish a novel diagnostic score model. Articles were identified by searching the PubMed, Web of Science, Google Scholar, China National Knowledge Infrastructure, and Wang Fang databases. Studies identified were pooled, and the standardized mean difference (SMD) and its corresponding 95% confidence interval (CI) were calculated. Subgroup analyses and publication bias detection were also conducted. Version 12.0 STATA software was used for statistical analysis. A final analysis of 1,327 subjects together (740 patients with lung neoplasms and 587 controls) was performed from 10 clinical case-control studies. The meta-analysis results showed a positive association between serum OPN levels and lung neoplasm (SMD=5.59, 95% CI: 1.85–3.32, P<0.001). The subgroup analysis by ethnicity detected that high levels of serum OPN may be the main risk factor for lung neoplasms in Asians (SMD=1.76, 95% CI: 1.24–2.29, P<0.001), but not in Caucasians (P=0.072). In conclusion, the present meta-analysis indicated that serum OPN levels were generally elevated in lung neoplasm patients, and thus, serum levels of OPN may be useful in diagnosing lung neoplasm in certain population groups.

Overexpression of osteopontin promotes resistance to cisplatin treatment in HCC

Osteopontin (OPN) is a multi-functional cytokine involved in cell survival, migration and adhesion. Increasing evidence has elucidated its role in tumorigenesis, progression and metastasis. However, the role of OPN in chemoresistance of human hepatocellular carcinoma (HCC) has not yet been clarified. In the present study, we examined the expression of OPN in human HCC samples before and after cisplatin-treatment, the results showed that OPN was significantly increased in cisplatin-resistant specimens. We then studied the effect of cisplatin on OPN expression in HCC cells, after exposure to cisplatin, the expression of OPN in HCC cells was elevated compared to control cells. We also found that PI3K/AKT signaling pathway was also activated by cisplatin and this effect was induced by the OPN pathway. To study the effect of OPN on chemoresistance, HCC cells were treated with cisplatin along with OPN. Incubation with OPN enchanced the chemoresistance of HCC cells to cisplatin. In contrast, blockage of OPN pathway promoted the chemosensitivity of HCC cells to cisplatin. Our results suggest that OPN enhanced chemoresistance of cisplatin in HCC cells by activating PI3K/AKT signaling pathway, blocking the OPN pathway might be a novel way to overcome the disease.

RNA-seq analysis of lung adenocarcinomas reveals different gene expression profiles between smoking and nonsmoking patients

Lung adenocarcinoma is caused by the combination of genetic and environmental effects, and smoking plays an important role in the disease development. Exploring the gene expression profile and identifying genes that are shared or vary between smokers and nonsmokers with lung adenocarcinoma will provide insights into the etiology of this complex cancer. We obtained RNA-seq data from paired normal and tumor tissues from 34 nonsmoking and 34 smoking patients with lung adenocarcinoma (GEO: GSE40419). R Bioconductor, edgeR, was adopted to conduct differential gene expression analysis between paired normal and tumor tissues. A generalized linear model was applied to identify genes that were differentially expressed in nonsmoker and smoker patients as well as genes that varied between these two groups. We identified 2273 genes that showed differential expression with FDR < 0.05 and |logFC| >1 in nonsmoker tumor versus normal tissues; 3030 genes in the smoking group; and 1967 genes were common to both groups. Sixty-eight and 70% of the identified genes were downregulated in nonsmoking and smoking groups, respectively. The 20 genes such as SPP1, SPINK1, and FAM83A with largest fold changes in smokers also showed similar large and highly significant fold changes in nonsmokers and vice versa, showing commonalities in expression changes for adenocarcinomas in both smokers and nonsmokers for these genes. We also identified 175 genes that were significantly differently expressed between tumor samples from nonsmoker and smoker patients. Gene expression profile varied substantially between smoker and nonsmoker patients with lung adenocarcinoma. Smoking patients overall showed far more complicated disease mechanism and have more dysregulation in their gene expression profiles. Our study reveals pathogenetic differences in smoking and nonsmoking patients with lung adenocarcinoma from transcriptome analysis. We provided a list of candidate genes for further study for disease detection and treatment in both smoking and nonsmoking patients with lung adenocarcinoma.

The reverse effect of X-ray irradiation on acquired gefitinib resistance in non-small cell lung cancer cell line NCI-H1975 in vitro

The clinical efficacy of gefitinib in the treatment of non-small cell lung cancer (NSCLC) with mutations in exon 18, 19 or 21 of epidermal growth factor receptor (EGFR) is limited by the acquired resistance to the drug. To explore whether X-ray irradiation could reverse the acquired gefitinib resistance in NSCLC cell in vitro. We chose a human NSCLC cell line NCI-H1975 to establish acquired gefitinib-resistant cell line named as NCI-H1975/GR. NCI-H1975/GR was irradiated with X-ray and then named as NCI-H1975/GR/XR. In the three cell lines, subsequently cell growth curves and cell population doubling time were calculated by cell proliferation assay, the changes of cell viability were evaluated by trypan blue dye exclusion method and MTT assay, the cell cycle distribution and apoptosis were investigated by flow cytometry, the expressions of E-cadherin and vimentin used to indicate epithelial-mesenchymal transition (EMT) were determined by western blot analysis, the protein expressions in EGFR/KRAS/BRAF transduction pathway were detected by immunocytochemistry, and the mutations of EGFR, KRAS and BRAF were detected by high resolution melting analysis and direct sequencing. We found that the X-ray irradiation enhanced the growth inhibitory effects of gefitinib on the acquired gefitinib-resistant cell line. Of NCI-H1975/GR/XR following gefitinib treatment, the IC50 decreased significantly, the cell proportion of phase G0/G1 was slightly higher, and the apoptosis cell proportion was significantly higher than those of NCI-H1975/GR. In addition, the reversal of EMT being present in NCI-H1975/GR cells was likely appearing in NCI-H1975/GR/XR cells. These results indicated that the acquired gefitinib resistance could be reversed by X-ray irradiation in NSCLC cell line NCI-H1975 harboring both the L858R and T790M mutation in vitro.