No abstract

The enzyme cyclooxygenase 2 (COX-2) is known to be involved in tumorigenesis and metastasis in certain types of cancer. Nevertheless, the prognostic value of COX-2 overexpression and its polymorphisms in patients with non-small cell lung cancer (NSCLC) have yet to be fully elucidated. The aim of the present study was to investigate the association between the three most commonly studied COX-2 gene polymorphisms (−1195 G/A, −765 G/C and 8473 T/C) with COX-2 expression and lung cancer risk in a Brazilian cohort. In the present hospital based, case-control retrospective study, 104 patients with NSCLC and 202 cancer free control subjects were genotyped for −1195 G/A, −765 G/C and 8473 T/C polymorphisms using allelic discrimination with a reverse transcription quantitative polymerase chain reaction method. COX-2 mRNA expression was analyzed in surgically resected tumors from 34 patients with NSCLC. The results revealed that COX-2 expression levels were higher in tumor tissue compared with normal lung tissue. However, this overexpression of COX-2 was not associated with the patient outcome, and furthermore, none of the analyzed polymorphisms were associated with the risk of developing lung cancer, COX-2 overexpression, or the overall survival of the patients with NSCLC. Taken together, the findings described in the present study do not support a major role for COX-2 polymorphisms and COX-2 overexpression in lung carcinogenesis within the Brazilian population.

Oral mucositis is an acute toxicity that occurs in patients submitted to chemoradiotherapy to treat head and neck squamous cell carcinoma. In this study, we evaluated differences in gene expression in the keratinocytes of the oral mucosa of patients treated with photobiomodulation therapy and tried to associate the molecular mechanisms with clinical findings. From June 2009 to December 2010, 27 patients were included in a randomized double-blind pilot study. Buccal smears from 13 patients were obtained at days 1 and 10 of chemoradiotherapy, and overall gene expression of samples from both dates were analyzed by complementary DNA (cDNA) microarray. In addition, samples from other 14 patients were also collected at D1 and D10 of chemoradiotherapy for subsequent validation of cDNA microarray findings by qPCR. The expression array analysis identified 105 upregulated and 60 downregulated genes in our post-treatment samples when compared with controls. Among the upregulated genes with the highest fold change, it was interesting to observe the presence of genes related to keratinocyte differentiation. Among downregulated genes were observed genes related to cytotoxicity and immune response. The results indicate that genes known to be induced during differentiation of human epidermal keratinocytes were upregulated while genes associated with cytotoxicity and immune response were downregulated in the laser group. These results support previous clinical findings indicating that the lower incidence of oral mucositis associated with photobiomodulation therapy might be correlated to the activation of genes involved in keratinocyte differentiation.

Platinum compounds remain the cornerstone for both early and advanced stages NSCLC management. However, mechanisms underlying platinum resistance and sensitivity are poorly understood, and no major impact in patient selection or treatment modulation has been achieved to date. Apoptosis inhibition and platinum-efflux are potential mechanisms, therefore we evaluated the role of XIAP, pAkt, and ATP7A in this setting. We have analyzed the tumor cell lines, LC94, LC319, and A549, all of adenocarcinoma histology and harboring KRAS mutations. The cisplatin (CPT) IC50 was assessed using MTT assay, after 48 h incubation. mRNA expression was evaluated by Real-time PCR, while Western blotting was performed to analyze protein expression. Also, two distinct cohorts of NSCLC patients were evaluated. The first was comprised of 39 patients diagnosed as early-stage NSCLC (IA-IIIB), whereas the second included patients with metastatic disease (IV). In the latter, patients were clinically classified as platinum-sensitive (N=4) and platinum-non-sensitive group (N=47). We have analyzed either mRNA expression or protein expression. NSCLC cell lines exhibited distinct profiles of CPT sensitivity. LC94 was especially sensitive to CPT, in contrast to LC319 and A549. Resistant cell lines (LC319 and A549) showed a positive correlation between high XIAP and ATP7A mRNA expression when compared to LC94. These data was corroborated by XIAP and ATP7A mRNA expression, which also showed a significant positive correlation (R2=0,88) in early-diagnosed patients (IA-IIIB). we did not correlate these data to response to CPT, since only few patients of this cohort received adjuvant therapy. XIAP protein expression was evaluated in cell lines and in the second clinical cohort. In fact, XIAP showed a considerably higher expression in LC 319 and A549 than in LC 94. Interestingly, XIAP shRNA lead not only to XIAP downregulation (85% reduction in mRNA compared to empty-vector control), but also to ATP7A (60% of reduction in mRNA). These changes were accompanied by reduction in the respective protein levels. Among patients with metastatic NSCLC, XIAP was expressed in 45% (21/47) in the platinum-non-sensitive group, while no expression was observed in the sensitive (0/4). Knowing that XIAP is regulated by PI3K/Akt pathway through phosphorylation at the serine 87 residue, which increases XIAP stability and accumulation, we further analyzed the Akt phosphorylation. LC319 displayed superior Akt phosporylation, in comparison to the lower level in LC 94. XIAP, pAkt, and ATP7A mRNA expression were positively correlated to CPT resistance/sensitivity in NSCLC. Furthermore, XIAP seems to indirectly regulate ATP7A transcritption and the correlation of expression of both proteins might cooperate for NSCLC chemoresistance. Further analyses are warranted to validate these findings and explore their potential as biomarkers in this setting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1731. doi:1538-7445.AM2012-1731

Some proteins, canonically not associated with amyloid diseases, can aggregate into amyloid-like fibrils under special conditions. Our group hypothesized that stressful cancer microenvironment might induce the formation of insoluble deposits of p53 mutant protein. A cohort of 28 non-small cell lung cancer (NSCLC) patients was used to test the aforementioned hypothesis. Tumor specimens were assessed for TP53 mutations using DNA sequencing and for amyloid formation by Congo red staining. TP53 mutations were present in 57% of patients, whereas no amyloid deposits were detected in tissue sections under polarized light microscopy. Mutant p53 proteins are not associated with the appearance of amyloid-like fibrils in NSCLC samples, and DNA sequencing remains the standard method to detect such abnormality.