Association between nuclear expression of retinoic acid receptor alpha and beta and clinicopathological features and prognosis of advanced non-small cell lung cancer.

BACKGROUND: Transcription factors such as retinoic acid receptor alpha (RARα) and beta (RARß) and Yin Yang 1 (YY1) are associated with the progression of non-small cell lung cancer (NSCLC). In particular, a lack of RARß expression is associated with NSCLC development. The aim of this study was to analyze the expression of RARα, RARß and YY1 and their relationship with prognosis in patients with advanced NSCLC. METHODS: The expression of RARα, RARß and YY1 was assessed by immunohistochemistry and quantitative computerized image software. RESULTS: Eighty-five patients treated with platinum-based chemotherapy were included in the analysis. The mean and standard deviation of the nuclear expression of RARα, RARß and YY1 were 184.5 ± 124.4, 18 ± 27 and 16.6 ± 20.5, respectively. The nuclear expression of RARß was associated with the nuclear expression of YY1 (R 2 = 0.28; p value < 0.0001). Patients with high nuclear expression of YY1 were likely to be non-smokers (61.9 vs 40.5 %). Median progression-free survival (PFS) was 5.9 months (3.48-8.28). Low expression of RARα was independently associated with worse PFS following chemotherapy (10.3 vs 5.46 months p = 0.040). Median overall survival (OS) was 15.6 months (4.5-26.7), and lower nuclear expression of RARß was independently associated with shorter OS (27.5 vs 8.7 months; p = 0.037). CONCLUSION: Our study suggests that the loss of RARs is associated with a worse prognosis and these receptors could be a potential molecular target for NSCLC.

All-trans retinoic acid induces nerve regeneration and increases serum and nerve contents of neural growth factor in experimental diabetic neuropathy.

Local diminution of the neural growth factor (NGF) contributes to the apparition of diabetic neuropathy. All-trans retinoic acid (RA) increases the expression of neural growth factor and its receptor participating in translation pathways. This study evaluates RA as a treatment of diabetic neuropathy: 120 mice were assigned randomly to 4 groups. Group A (n = 30) was taken as control; group B (n = 30) received 50 mg/kg intraperitoneal streptozotocin (STZ); group C (n = 30) received STZ, and after diabetic neuropathy developed, they were treated with subcutaneous RA 20 mg/kg daily during 60 days; and group D (n = 30) only received RA. Plasma glucose, thermosensitive tests, serum, and the nerve contents of NGF were measured in all animals. Evaluation by electron microscopy was performed in search of morphologic changes secondary to neuropathy and nerve regeneration. Diabetic mice had an increased threshold to pain. Treatment with RA in diabetic mice reverted changes in sensitivity as compared with diabetic mice that received placebo (P < 0.001). No differences in pain threshold among controls, RA, and diabetes mellitus (DM) + RA groups were found. Glucose levels were not affected by the treatment with RA. NGF diminished significantly in the sciatic nerve in diabetic mice as compared with controls and with the RA group. Animals with DM + RA had a significant increase of NGF in nerves as compared with the other groups. RA also regressed the ultrastructural changes induced by diabetes that showed increased neural regeneration. RA can revert functional and ultrastructural changes and induce neural regeneration after the establishment of diabetic neuropathy, possibly because of the increased of NGF concentrations in nerve terminals.