Expression levels of some antioxidant and epidermal growth factor receptor genes in patients with early-stage non-small cell lung cancer

Heme-Derived Metabolic Signals Dictate Immune Responses

Heme is one of the most abundant molecules in the body acting as the functional core of hemoglobin/myoglobin involved in the O₂/CO₂ carrying in the blood and tissues, redox enzymes and cytochromes in mitochondria. However, free heme is toxic and therefore its removal is a significant priority for the host. Heme is a well-established danger-associated molecular pattern (DAMP), which binds to toll-like receptor 4 (TLR4) to induce immune responses. Heme-derived metabolites including the bile pigments, biliverdin (BV) and bilirubin (BR), were first identified as toxic drivers of neonatal jaundice in 1800 but have only recently been appreciated as endogenous drivers of multiple signaling pathways involved in protection from oxidative stress and regulators of immune responses. The tissue concentration of heme, BV and BR is tightly controlled. Heme oxygenase-1 (HO-1, encoded by HMOX1) produces BV by heme degradation, while biliverdin reductase-A (BLVR-A) generates BR by the subsequent conversion of BV. BLVR-A is a fascinating protein that possesses a classical protein kinase domain, which is activated in response to BV binding to its enzymatic site and initiates the downstream mitogen-activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways. This links BLVR-A activity to cell growth and survival pathways. BLVR-A also contains a bZip DNA binding domain and a nuclear export sequence (NES) and acts as a transcription factor to regulate the expression of immune modulatory genes. Here we will discuss the role of heme-related immune response and the potential for targeting the heme system for therapies directed toward hepatitis and cancer.

Activity of Antioxidant Enzymes in the Tumor and Adjacent Noncancerous Tissues of Non-Small-Cell Lung Cancer

Lung tissue is directly exposed to high oxygen pressure, as well as increased endogenous and exogenous oxidative stress. Reactive oxygen species (ROS) generated in these conditions play an important role in the initiation and promotion of neoplastic growth. In response to oxidative stress, the antioxidant activity increases and minimizes ROS-induced injury in experimental systems. The aim of the present study was to evaluate the activity of antioxidant enzymes, such as superoxide dismutase (SOD; isoforms: Cu/ZnSOD and MnSOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione S-transferase (GST), along with the concentration of malondialdehyde (MDA) in tumor and adjacent noncancerous tissues of two histological types of NSCLC, i.e., adenocarcinoma and squamous cell carcinoma, collected from 53 individuals with surgically resectable NSCLC. MDA concentration was similar in tumors compared with adjacent noncancerous tissues. Tumor cells had low MnSOD activity, usually low Cu/ZnSOD activity, and almost always low catalase activity compared with those of the corresponding tumor-free lung tissues. Activities of GSH-related enzymes were significantly higher in tumor tissues, irrespective of the histological type of cancer. This pattern of antioxidant enzymes activity could possibly be the way by which tumor cells protect themselves against increased oxidative stress.

Comparison of redox parameters in ovarian endometrioma and its malignant transformation

The present study aimed to evaluate the levels of oxidative stress and antioxidant markers in benign endometrioma (OE) and its malignant transformation [endometriosis-associated ovarian cancer (EAOC)] by measuring 8-hydroxy-2-deoxyguanosine (8-OHdG), heme oxygenase-1 (HO-1) and total antioxidant capacity (TAC/Heme-iron) alterations associated with disease progression. Cyst fluid samples from 44 patients with OE and 14 patients with EAOC were studied using an enzyme-linked immunosorbent assay. A χ² test, t-test and Pearson correlation test were performed using SPSS version 22.0. The cut-off point, sensitivity and specificity of each marker for EAOC diagnosis were evaluated by receiver operating characteristic curve analysis. Cyst fluid 8-OHdG and HO-1 levels in the EAOC group were significantly decreased compared with the OE subjects (P=0.013 and P<0.001, respectively). The levels of TAC/Heme-iron in patients with EAOC were significantly higher compared with those in the OE subjects (P<0.001). The present study demonstrated a positive correlation between 8-OHdG and HO-1 levels (P=0.012). HO-1 exhibited the highest discriminant value for EAOC (Area Under the Curve=0.901). The optimal cut-off point of HO-1 for the diagnosis of EAOC was 2.314 ng/ml, with a sensitivity and specifity of 95.2 and 85.7%, respectively. The present study revealed a clear separation between the overall redox state in OE and EAOC. It was concluded that characteristic alterations in important factors in redox may be helpful for understanding the pathogenesis of the malignant transformation of endometriosis.

Specific protein carbonylation in human breast cancer tissue compared to adjacent healthy epithelial tissue

Protein carbonylation is an irreversible post-translational modification induced by severe oxidative stress. Reactive oxygen species (ROS) are constantly produced in cells and play important roles in both cancer progression and cancer suppression. ROS levels can be higher in tumor compared to surrounding healthy tissue but ROS-induced specific protein carbonylation and its unique role in cancer progression or suppression is poorly understood. In this study, we utilized previously validated ELISA and western blot methods to analyze the total and specific protein carbonylation in flash-frozen human breast cancer and matched adjacent healthy tissue to compare relative total, and specific protein carbonylation. Mass spectrometry, two-color western, and immunoprecipitation methods were used to identify and confirm the specifically carbonylated proteins in breast tumor tissue. Superoxide dismutase (SOD) activity was measured as an indicator of antioxidant activity, and LC3-II protein level was analyzed for autophagy by western blot. Findings were further confirmed using the immortalized MDA-MB-231 and MDA-MB-468 breast cancer and MCF-12A noncancerous human epithelial breast cell lines. Our results indicate that tumor tissue has greater total protein carbonylation, lower SOD1 and SOD2 protein levels, lower total SOD activity, and higher LC3-II levels compared to adjacent healthy tissue. We identified and confirmed three specific proteins of interest; filamin A, heat shock protein 90β (HSP90β), and bifunctional glutamate/proline-tRNA ligase (EPRS), that were selectively carbonylated in tumor tissue compared to matched adjacent healthy tissue. Correspondingly, compared to noncancerous MCF-12A epithelial cells, MDA-MB-231 cancer cells exhibited an increase in filamin A and EPRS protein carbonylation, decreased total SOD activity, and increased autophagy, but not increased HSP90β protein carbonylation. Identification of selectively carbonylated proteins and defining their roles in cancer progression may promote the development of targeted therapeutic approaches toward mitigating oxidative damage of these proteins.

Heme oxygenase-1 retards hepatocellular carcinoma progression through the microRNA pathway

Heme metabolism system is involved in microRNA (miRNA) biogenesis. The complicated interplay between heme oxygenase-1 (HO-1) and miRNA has been observed in various tissues and diseases, including human malignancy. In the present study, our data showed that stable HO-1 overexpression in hepatocellular carcinoma (HCC) cells downregulated several oncomiRs. The most stably downregulated are miR-30d and miR-107. Iron, one of HO-1 catalytic products, was an important mediator in this regulation. Cell function analysis demonstrated that HO-1 inhibited the proliferation and metastasis of HepG2 cells, whereas miR-30d/miR-107 improved the proliferative and migratory ability of HepG2 cells. The beneficial effect of HO-1 in HCC inhibition could be reversed by upregulating miR-30d and miR-107. Akt and ERK pathways may be involved in the regulation of HO-1/miR-30d/miR-107 in HCC. These data indicate that HO-1 significantly suppresses HCC progression by regulating the miR-30d/miR-107 level, suggesting miR-30d/miR-107 regulation as a new molecular mechanism of HO-1 anticancer effect.

Comparative proteomic profiling of triple-negative breast cancer reveals that up-regulation of RhoGDI-2 is associated to the inhibition of caspase 3 and caspase 9

There are no targeted therapeutic modalities for triple-negative breast cancer (TNBC), thus it is associated with poor prognosis and worst clinical outcome. Here, our aim was to identify deregulated proteins in TNBC with potential therapeutic applications. Proteomics profiling of TNBC and normal breast tissues through two-dimensional electrophoresis and ESI-MS/MS mass spectrometry revealed the existence of 16 proteins (RhoGDI-2, HSP27, SOD1, DJ1, UBE2N, PSME1, FTL, SH3BGRL, and eIF5A-1) with increased abundance in carcinomas. We also evidenced for the first time the deregulation of COX5, MTPN and DB1 proteins in TNBC that may represent novel tumor markers. Particularly, we confirmed the overexpression of the Rho-GDP dissociation inhibitor 2 (RhoGDI-2) in distinct breast cancer subtypes, as well as in metastatic cell lines derived from lung, prostate, and breast cancer. Remarkably, targeted disruption of RhoGDI-2 by RNA interference induced mitochondrial dysfunction, and facilitated caspase-3 and -9 activation in two breast cancer cell lines. Moreover, suppression of RhoGDI-2 resulted in a robust sensitization of breast cancer cells to cisplatin therapy. In conclusion, we identified novel proteins deregulated in TNBC, and confirmed the overexpression of RhoGDI-2. We propose that RhoGDI-2 inhibition may be exploited as a potential therapeutic strategy along cisplatin-based chemotherapy in breast cancer.

BIOLOGICAL SIGNIFICANCE

There are no useful biomarkers neither targeted therapeutic modalities for triple-negative breast cancer, which highly contributes to the poor prognosis of this breast cancer subtype. In this work, we used two-dimensional electrophoresis and ESI-MS/MS spectrometry to identify novel deregulated proteins in breast cancer tissues. Particularly, our results showed that RhoGDI-2, a protein that has been associated to metastasis and poor survival in human cancers, is overexpressed in different subtypes of breast tumors, as well as in metastatic cell lines derived from lung, prostate, and breast cancer. Our data also provided novel insights about the role of RhoGDI-2 in apoptosis through intrinsic pathway inhibition. Importantly, they suggested that targeted modulation of RhoGDI-2 levels might be a useful strategy for breast cancer therapy.

Correlation study and significance of the EGFR expression in serum, lymph nodes and tumor tissue of NSCLC

BACKGROUND

This study was designed to detect the protein expression of epidermal growth factor receptor (EGFR) among serum, lymph node, and tumor tissues, and to discuss their relationship and clinical significance. We investigated whether EGFR levels in serum and lymph nodes could be used as an effective method for non-small cell lung cancer (NSCLC) to diagnose and assess clinical stage.

METHODS

In 56 patients with NSCLC and 10 individuals with nonmalignant thoracic disease, we measured EGFR levels in serum using an enzyme immunoassay, and EGFR mRNA levels in lymph node and NSCLC tissues by quantitative real-time-polymerase chain reaction. We examined the correlation between them and with the clinical parameters.

RESULTS

Serum EGFR levels substantially decreased after surgical treatment (P < 0.001). Serum EGFR levels were correlated with smoking, surgery, and pathological type after surgery (all P < 0.05). EGFR mRNA levels in lymph node and tumor tissues were correlated more closely with lymph node metastasis (P = 0.015. EGFR mRNA in tissues was higher than that of benign pulmonary diseases (P = 0.020). There was an obvious positive correlation among EGFR levels of serum and lymph node tissues (r = 0.764; P < 0.001), serum and tumor tissues (r = 0.616; P < 0.001), and lymph node and tumor tissues (r = 0.904; P < 0.001) in NSCLCs.

CONCLUSION

The data suggest that detecting EGFR levels in serum and lymph node tissues could be a simple and effective method to diagnose and assess the clinical stage in patients with NSCLC.

Interplay between heme oxygenase-1 and miR-378 affects non-small cell lung carcinoma growth, vascularization, and metastasis

AIMS

Heme oxygenase-1 (HO-1, HMOX1) can prevent tumor initiation; while in various tumors, it has been demonstrated to promote growth, angiogenesis, and metastasis. Here, we investigated whether HMOX1 can modulate microRNAs (miRNAs) and regulate human non-small cell lung carcinoma (NSCLC) development.

RESULTS

Stable HMOX1 overexpression in NSCLC NCI-H292 cells up-regulated tumor-suppressive miRNAs, whereas it significantly diminished the expression of oncomirs and angiomirs. The most potently down-regulated was miR-378. HMOX1 also up-regulated p53, down-regulated angiopoietin-1 (Ang-1) and mucin-5AC (MUC5AC), reduced proliferation, migration, and diminished angiogenic potential. Carbon monoxide was a mediator of HMOX1 effects on proliferation, migration, and miR-378 expression. In contrast, stable miR-378 overexpression decreased HMOX1 and p53; while enhanced expression of MUC5AC, vascular endothelial growth factor (VEGF), interleukin-8 (IL-8), and Ang-1, and consequently increased proliferation, migration, and stimulation of endothelial cells. Adenoviral delivery of HMOX1 reversed miR-378 effect on the proliferation and migration of cancer cells. In vivo, HMOX1 overexpressing tumors were smaller, less vascularized and oxygenated, and less metastatic. Overexpression of miR-378 exerted opposite effects. Accordingly, in patients with NSCLC, HMOX1 expression was lower in metastases to lymph nodes than in primary tumors.

INNOVATION AND CONCLUSION

In vitro and in vivo data indicate that the interplay between HMOX1 and miR-378 significantly modulates NSCLC progression and angiogenesis, suggesting miR-378 as a new therapeutic target. REBOUND TRACK: This work was rejected during standard peer review and rescued by Rebound Peer Review (Antioxid Redox Signal 16, 293-296, 2012) with the following serving as open reviewers: James F. George, Mahin D. Maines, Justin C. Mason, and Yasufumi Sato.

High expression of heme oxygenase-1 is associated with tumor invasiveness and poor clinical outcome in non-small cell lung cancer patients

BACKGROUND

Heme oxygenase-1 (HO-1), a rate-limiting enzyme in heme catabolism, is known to play a role in the protection of cells against oxidative stress, inflammation, anomalous proliferation and apoptosis. As yet, the role of HO-1 expression in non-small cell lung cancer (NSCLC) development and metastasis remains unclear and insufficient data are available regarding its impact on the prognosis of NSCLC patients.

METHODS

Seventy NSCLC patients who underwent surgical resection were included in this HO-1 expression study and, concomitantly, clinical parameters were collected. Two lung adenocarcinoma cell lines (A549 and H441) were used to assess both invasive and migratory parameters in vitro.

RESULTS

NSCLC patients with a high HO-1 expression ratio (tumor tissue/normal tissue) (> 1) exhibited a significantly poorer prognosis and a higher metastatic rate compared to those with a low HO-1 expression ratio (p < 0.05). The invasive and migratory abilities of A549 and H441 cells significantly increased after exogenous HO-1 over-expression and significantly decreased after siRNA-mediated HO-1 expression silencing. HO-1 up- and down-regulation also positively correlated with the expression of metastasis-associated proteins EGFR, CD147 and MMP-9. In addition, we found that HO-1 expression can be inhibited by PI3K and AKT inhibitors, but not by MAPK inhibitors.

CONCLUSIONS

HO-1 is a poor prognostic NSCLC predictor and its over-expression may increase the metastatic potential of NSCLC. Based on our findings and those of others, HO-1 may be considered as a novel NSCLC therapeutic target.

Expression of heme oxygenase-1 in non-small cell lung cancer (NSCLC) and its correlation with clinical data

While changes in heme oxygenase (HO-1) in lung cancer have already been reported, conflicting results were obtained for enzyme expression in human lung cancer specimens. Therefore, the aim of this work was to study HO-1 expression in a large collection of human lung cancer samples. For this purpose, we analyzed the expression of HO-1 in an organized tissue microarray (TMA) and investigated its correlation with clinicopathological data. Ninety-six percent of tumor samples were positive for HO-1, and the expression of HO-1 was significantly higher in cancerous than in non-cancerous tissues. Importantly, HO-1 expression correlated with advanced stages and lymph node involvement. Additionally, quantitative RT-PCR in 18 pairs of human lung carcinomas and their adjacent non-malignant tissues was performed. Our results demonstrate that HO-1 protein is upregulated in epithelial malignant cells in NSCLC and its expression is associated with higher stages of the disease. Additionally, different subcellular localization is observed between tumor and adjacent non-malignant tissues.