Objective: To investigate the effect of β,-sitosterol on endometrial cells to understand the underlying mechanism. Materials and Methods: This is a laboratory-based experimental study conducted on animals and cells. Histological assays were performed to determine the effect of β,-sitosterol on endometrial cells. The CCK-8 assay was used to assess the inhibitory effect of β,-sitosterol on the proliferation of ectopic endometrial stromal cells (hEM15A). Flow cytometry was performed to evaluate the induction of apoptosis by β,-sitosterol in hEM15A cells. The transwell invasion assay was conducted to measure the suppression of hEM15A cell migration by β,-sitosterol. Western blot analyses were performed to analyze the effect of β,-sitosterol on the expression of Smad family member 7 (Smad7) and the activity of transforming growth factor-β,(TGF-β, 1), as well as the phosphorylation of Smad2 and Smad3. Results: Histological assays showed that β,-sitosterol regulates histopathology and induces apoptosis of endometrial cells in vivo. The CCK-8 assay revealed that β,-sitosterol could inhibit the proliferation of hEM15A in human endometriosis patients. Flow cytometry showed that apoptosis was triggered by β,-sitosterol in hEM15A. The transwell invasion assay indicated that the hEM15A migration under the β,-sitosterol treatment group was suppressed. Western blot analyses suggested that β,-sitosterol increased the expression of Smad7, decreased the activity of TGF-β, 1, and reduced the phosphorylation of Smad2 and Smad3. The effect of β,-sitosterol was weakened by the silence of Smad7. Conclusion: The results suggest that β,-sitosterol can inhibit the proliferation of endometrial cells and relieve endometriosis by inhibiting TGF-β,-induced phosphorylation of Smads through regulation of Smad7.

Aim: Our aim was to investigate the association between two single nucleotide polymorphisms (SNPs) of SMAD7 and the risk of CRC among Iranian individuals. Background: Genome-wide association studies (GWAS) have identified 18q21 as a risk locus for colorectal cancer (CRC), which maps to the SMAD7 gene. Methods: This case– control study was conducted on 109 CRC cases and 109 controls in the Iranian population to evaluate the influence of two SNPs of SMAD7, rs2337106 and rs6507874, on the risk of CRC as well as on clinicopathological features. Genotype determination was performed by TaqMan assay via an ABI 7500 Real Time PCR System (Applied Biosystems) for the DNA of peripheral blood. Descriptive analysis and logistic regression model were used for statistical analyses. Results: Genotyping of the SNPs in the SMAD7 gene revealed that the frequency of G allele of rs2337106 was 53. 7% in controls and 56. 4% in cases (p-value=0. 564) while the frequency of C allele of rs6507874 was 55. 5% in controls and 56. 3% in cases (pvalue= 0. 772). Further, there were no significant differences in genotype frequencies of these SNPs between CRC patients and controls. The SMAD7 genotypes were not associated with the risk of CRC or with any clinicopathological characteristics such as tumor site, tumor grade, and stage TNM in CRC patients (p-value>0. 05), even after adjustment for sex, age, and smoking status. Conclusion: Our results provided the first evidence that SMAD7 genotypes, rs2337106 and rs6507874, could not be predisposing markers in genetic susceptibility to CRC in an Iranian population, at least in the studied population.

Sulfur mustard (SM)-exposed individuals develop late pulmonary complications, which are associated with chronic inflammation and fibrotic changes in the lung tissue. MicroRNAs are known to act as important regulators of inflammatory responses, including inflammation and fibrosis-related cytokine signaling. In this study, we investigated the expression miR-15b-5p and miR-21-5p, two regulators of TGF-β signaling, as well as their target molecule, SMAD7, in lung tissues from SM-exposed and control individuals. Total RNA was extracted from formalin-fixed paraffin-embedded (FFPE) lung tissue biopsies obtained during surgery from SM-exposed (n=20) or control (n=20) cases. Quality of the extracted RNA was evaluated by an Agilent Bioanalyzer and RNA was quantified using a NanoDrop. MiR-21-5p, miR-15b-5p and SMAD7 expression levels were measured by realtime RT-PCR. miR-21-5p expression levels were significantly decreased (2. 7 fold) in the lung tissues from SM-exposed individuals compared with tissues obtained from the control group(p=0. 02). There were no significant differences in miR-15b-5p expression levels between the two groups(p=0. 94). Interestingly, SMAD7 expression levels were significantly higher (5. 8 fold) in SM-exposed individuals’ lung tissues compared with the control group(p=0. 045). Our data indicate that exposure to sulfur mustard affects the expression of miR-21-5p as well as its target, SMAD7, in lung tissues many years after exposure. Considering the role of SMAD7 in the regulation of TGF-β signaling, these changes might point to a potential mechanism by which SM-exposure regulates inflammatory/fibrotic alterations in lung tissue.