ABSTRACT
Intracellular lipid accumulation has been associated with a poor prognosis in cancer. We have previously reported the involvement of lipid droplets in cell proliferation in colon cancer cells, suggesting a role for these organelles in cancer development. In this study, we evaluate the role of lipid droplets in cell cycle regulation and cellular transformation. Cell cycle synchronization of NIH 3T3 cells revealed increased numbers and dispersed distribution of lipid droplets specifically during S phase. Also, the transformed cell lineage NIH 3T3-H-rasV12 showed an accumulation of both lipid droplets and PLIN2 protein above the levels in NIH 3T3 cells. PLIN2 gene overexpression, however, was not able to induce NIH 3T3 cell transformation, disproving the hypothesis that PLIN2 is an oncogene. Furthermore, positive PLIN2 staining was strongly associated with highly proliferative Ki-67-positive areas in human colon adenocarcinoma tissue samples. Taken together, these results indicate that cell cycle progression is associated with tight regulation of lipid droplets, a process that is altered in transformed cells, suggesting the existence of a mechanism that connects cell cycle progression and cell proliferation with lipid accumulation.
Subject(s)
Adenocarcinoma/metabolism , Cell Transformation, Neoplastic/metabolism , Colonic Neoplasms/metabolism , Lipid Droplets/metabolism , Perilipin-2/metabolism , Adenocarcinoma/genetics , Animals , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Cell Cycle , Cell Proliferation , Cell Transformation, Neoplastic/genetics , Colonic Neoplasms/genetics , Disease Progression , Gene Expression Regulation, Neoplastic , Humans , Mice , NIH 3T3 Cells , Perilipin-2/genetics , Proto-Oncogene Proteins p21(ras)/genetics , Up-RegulationABSTRACT
Esophageal squamous cell carcinoma (ESCC) is highly fatal due to late diagnosis and inefficient treatment. Early disease detection could improve diagnosis and patient survival. Esophageal squamous epithelial cells express SPRR3, a member of the small proline-rich protein family, which is downregulated in ESCC. Therefore, SPRR3 expression may be used as a biomarker to follow the transition from healthy mucosa to ESCC. Both SPRR3 mRNA splice variants, v1 and v2, were evaluated by real time PCR in tumor and histologically normal adjacent tissue biopsies from 84 ESCC patients and 18 healthy controls. SPRR3-v1 was most highly expressed in the esophageal mucosa of healthy subjects, with an increasingly lower expression in the adjacent mucosa of ESCC patients and in tumors, respectively. SPRR3-v2 expression was low in normal mucosa and in tumors but it was higher in the adjacent mucosa of ESCC patients. In addition, we found a significant correlation between a lower SPRR3-v1 and SPRR3-v2 expression and age and alcohol consumption, respectively. SPRR3 protein expression presented a good correlation with SPRR3 mRNA expression. Cut-off points to discriminate between healthy mucosa, tumor and adjacent mucosa were determined with receiver operating characteristic (ROC) curves. This analysis showed that SPRR3-v1 expression discriminates the esophageal mucosa of healthy subjects from the adjacent mucosa and the tumor of ESCC patients with high sensitivity and specificity. Our data shows that the quantitative analysis of SPRR3 mRNA is a robust and reliable method to monitor the malignant transformation of the healthy esophageal mucosa into ESCC.
Subject(s)
Biomarkers, Tumor/genetics , Carcinoma, Squamous Cell/genetics , Cornified Envelope Proline-Rich Proteins/genetics , Esophageal Neoplasms/genetics , Reverse Transcriptase Polymerase Chain Reaction , Aged , Biomarkers, Tumor/metabolism , Carcinoma, Squamous Cell/pathology , Cornified Envelope Proline-Rich Proteins/metabolism , Demography , Esophageal Neoplasms/pathology , Female , Gene Expression Regulation, Neoplastic , Humans , Immunohistochemistry , Male , Middle Aged , RNA, Messenger/genetics , RNA, Messenger/metabolism , ROC Curve , Sensitivity and SpecificityABSTRACT
Schistosoma mansoni has been reported to cause a downregulation of hepatic cytochrome P450 activities after granulomas are formed around worm eggs harbored in the mouse liver. Only a few studies, however, provided data on the activity of xenobiotic-biotransaformation enzymes in the early phase of S. mansoni infection. In this study, we evaluated the alterations of liver microsomal enzymes during early infection (post-infection days, PIDs, 15 and 30) when granulomas are not found in the mouse liver yet. Swiss Webster (SW) and DBA/2 mice of either sex were infected with 100 S. mansoni cercariae on postnatal day 10. Levels of total-CYPs and activities of alkoxyresorufin-O-dealkylases (EROD, MROD, PROD and BROD), N-nitrosodimethylamine-N-demethylase (NDMA-d), coumarin 7-hydroxylase (COH, DBA/2 only) and UDP-glucuronosyltransferase (UGT) were measured in liver microsomes from mice killed on PIDs 15 and 30. Age-matched (sham-infected) mice of the same sex and strain were used as controls. Neither total-CYP levels nor microsomal enzyme activities were altered in SW and DBA/2 mice on PID 15. On PID 30, total-CYP levels, and COH, PROD and UGT activities remained unaltered, while gender- and strain-specific minor changes of EROD, MROD, BROD and NDMA-d (i.e., increase in SW and reduction in DBA/2) were found. In conclusion, our results suggest that, contrasting to a consistent and almost generalized downregulation of CYPs in chronic schistosomiasis, alterations of hepatic CYPs in early (acute) infection are isoform and mouse's gender and strain specific.
