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Carcinogenesis is related to the loss of homeostatic control of cellular processes regulated by transcriptional circuits and epigenetic mechanisms. Among these, the activities of peroxisome proliferator-activated receptors (PPARs) and DNA methyltransferases (DNMTs) are crucial and intertwined. PPARγ is a key regulator of cell fate, linking nutrient sensing to transcription processes, and its expression oscillates with circadian rhythmicity. Aim of our study was to assess the periodicity of PPARγ and DNMTs in pancreatic cancer (PC). We investigated the time-related patterns of PPARG, DNMT1, and DNMT3B expression monitoring their mRNA levels by qRT-PCR at different time points over a 28-hour span in BxPC-3, CFPAC-1, PANC-1, and MIAPaCa-2 PC cells after synchronization with serum shock. PPARG and DNMT1 expression in PANC-1 cells and PPARG expression in MIAPaCa-2 cells were characterized by a 24 h period oscillation, and a borderline significant rhythm was observed for the PPARG, DNMT1, and DNMT3B expression profiles in the other cell lines. The time-qualified profiles of gene expression showed different shapes and phase relationships in the PC cell lines examined. In conclusion, PPARG and DNMTs expression is characterized by different timequalified patterns in cell lines derived from human PC, and this heterogeneity could influence cell phenotype and human disease behaviour. [ABSTRACT FROM AUTHOR]

Emerging evidence indicates that peroxisome proliferator-activated receptor γ (PPARγ) and DNA methyltransferases (DNMTs) play a role in carcinogenesis. In this study we aimed to evaluate the expression of PPARγ, DNMT1, and DNMT3B and their correlation with clinical-pathological features in patients with pancreatic cancer (PC), and to define the effect of PPARγ activation on DNMTs expression in PC cell lines. qRT-PCR analysis showed that DNMT3B expression was downregulated in tumors compared to normal tissues (P = 0.03), whereas PPARγ and DNMT1 levels did not show significant alterations in PC patients. Expression levels between PPARγ and DNMT1 and between DNMT1 and DNMT3B were highly correlated (P = 0.008 and P = 0.05 resp.). DNMT3B overexpression in tumor tissue was positively correlated with both lymph nodes spreading (P = 0.046) and resection margin status (P = 0.04), and a borderline association with perineural invasion (P = 0.06) was found. Furthermore, high levels of DNMT3B expression were significantly associated with a lower mortality in the whole population (HR = 0.485; 95% CI = 0.262-0.895, P = 0.02) and in the subgroup of patients without perineural invasion (HR = 0.314; 95%CI = 0.130-0.758; P = 0.01), while such association was not observed in patients with tumor invasion into perineural structures (P = 0.70). In conclusion, in vitro and in vivo PPARγ and DNMTs appear interrelated in PC, and this interaction might influence cell phenotype and disease behavior. [ABSTRACT FROM AUTHOR]