Polymorphisms in the transforming growth factor‐β1 gene and the risk of asthma: A meta‐analysis

Background and objective: Polymorphisms in the transforming growth factor‐β1 (TGF‐β1) gene have been implicated in susceptibility to asthma, but a large number of studies have reported inconclusive results. A meta‐analysis was performed to investigate the association between polymorphisms in the TGF‐β1 gene and asthma susceptibility. Methods: Searches were performed of Medline (Ovid), PubMed, the Chinese Biological Medicine Database (CBM), the Chinese Journals Full‐text Database (CNKI), the Cochrane Library Database and the Web of Science, covering all papers published up to 30 April 2009. Statistical analysis was performed using Revman4.2.8 and STATA10.0 software. Results: Two polymorphisms (?509C/T and 915G/C(G25C)) were investigated in 14 studies, involving 2979 asthma patients and 4941 control subjects. The results showed that individuals carrying the ?509T allele (TT+TC) had a 36% increased risk of asthma, when compared with homozygotes (?509CC) (OR 1.36, 95% CI: 1.12–1.65). However, there was no significant association with risk of asthma in carriers of the 915C allele (GC+CC) compared with 915GG homozygotes (OR 1.05, 95% CI: 0.65–1.70). In a subgroup analysis by ethnicity, the risk of asthma associated with the ?509T allele was significantly elevated among Asians (OR 1.50, 95% CI: 1.04–2.17) but not Caucasians (OR 1.16, 95% CI: 1.00–1.36). In a subgroup analysis by age, the ?509T allele was associated with a significantly elevated risk of asthma among adults (OR 1.45, 95% CI: 1.09–1.92) but not children (OR 1.19, 95% CI: 0.96–1.46). Conclusions: This meta‐analysis suggested that the ?509C/T polymorphism in the TGF‐β1 gene may be a risk factor for asthma. To further evaluate gene–gene and gene–environment interactions between polymorphisms in the TGF‐β1 gene and asthma susceptibility, more studies involving thousands of patients are required.     

Changes in angiogenesis and hypoxia‐inducible factor‐1α protein expression in relapsed/refractory indolent non‐Hodgkin lymphomas

Angiogenesis is involved in the pathogenesis and progression of non‐Hodgkin lymphomas (NHL), and hypoxia‐inducible factor‐1α (HIF‐1α, also termed HIF1A) might contribute to this process. Currently, there is no direct evidence that the clinical progression of indolent NHL is associated with angiogenesis, and the expression of HIF‐1α at recurrence is unknown. Matched lymph node biopsies at diagnosis and recurrence of relapsed/refractory indolent NHL patients were analysed by immunohistochemical and morphometric analysis. We observed an increased vascular network and HIF‐1α protein expression in the second biopsy, providing direct evidence that angiogenesis is an essential process for disease progression.     

New mechanism of transforming growth factor‐β signaling in hepatoma: Dramatic up‐regulation of tumor initiating cells and epidermal growth factor receptor expression

Aim: Transforming growth factor‐β (TGF‐β) has dual activity in tumor cells. We studied the effect of TGF‐β on tumor‐initiating cells (TICs), which are similar in self‐renewal and differentiation features to normal adult stem cells. Methods: We used side population (SP) cells that exclude DNA binding dye Hoechst 33342 to obtain TICs, studied the differences in the kinetics of the SP cell response to TGF‐β treatment between hepatic tumor cell lines, and performed gene analysis. Results: SP cells from all cell lines have higher proliferative ability compared to non‐SP cells and they are drug resistant. TGF‐β treatment increased the percentage of SP cells (%SP) and the survival rate; chemotherapeutic drug resistance developed only in K‐251 SP cells. Gene analysis showed that TGF‐β up‐regulated epidermal growth factor receptor (EGFR) only in K‐251 cells. There were no EGFR mutations in K‐251, which had been reported in lung cancer. Knockdown of Smad4 using the small‐interfering RNA technique in K‐251 cells inhibited EGFR overexpression and significantly decreased the %SP. In contrast, the JNK inhibitor had little effect on EGFR expression or the %SP. Conclusion: TGF‐β treatment of K‐251 cells causes tumor progression and the anti‐cancer drug resistant phenotype by increasing SP.     

The primary mitogen (TCPOBOP)‐induced hepatocyte proliferation is resistant to transforming growth factor‐ β‐1 inhibition

Background: Transforming growth factor (TGF)‐β‐1 is a very efficient inhibitor of hepatocyte proliferation in various in vivo and in vitro experimental systems. However, there are no data on whether it can influence the mitogenic response induced by primary hepatocyte mitogens. Aims: In this study, we compared the proliferative response in the liver between wild‐type and transgenic mice, overexpressing active TGF‐β‐1 in their liver following the treatment by a primary hepatocyte mitogen TCPOBOP (1,4‐bis[2‐(3,5‐dichloropyridyloxy)]benzene). Methods: The proliferative response was characterized by the immunohistochemical examination of pulse and cumulative bromodeoxyuridine labelling and by quantitative real‐time polymerase chain reaction analysis of cell cycle‐related genes. Results: Neither of the applied techniques revealed significant differences between the two groups of mice; furthermore, we observed the upregulation of TGF‐β‐1 expression following the mitogenic treatment. Conclusions: TGF‐β‐1 does not inhibit the primary mitogen‐induced proliferative response of the hepatocytes. This observation may provide an explanation for the divergent consequences of hepatic proliferations induced by partial hepatectomy or primary mitogenic treatment.     

The −509C/T polymorphism of transforming growth factor‐β1 is associated with increased risk for development of chronic idiopathic neutropenia

Objective: Impaired granulopoiesis in chronic idiopathic neutropenia (CIN) has been associated with an inflammatory bone marrow (BM) microenvironment consisting of pro‐inflammatory and pro‐apoptotic mediators, such as tumor necrosis factor (TNF)‐α, transforming growth factor (TGF)‐β1, and Fas‐Ligand (Fas‐L). In this study, we evaluated the frequency of TNF‐α, TGF‐β1 and Fas‐L gene polymorphisms in CIN patients and explored their role in excessive cytokine production and their association with CIN development. Methods: The TNF‐α?308G/A, TGF‐β1 ?509C/T, +869T/C, +915G/C, and Fas‐L ?844T/C polymorphisms were studied in 57 CIN patients, and 100 healthy controls from Crete, a well‐defined area with genetically homogeneous population, using a polymerase chain reaction‐based restriction fragment length polymorphism assay. Results: The mutant genotype C/T or T/T of TGF‐β1 ?509C/T polymorphism was more common in CIN patients than in controls (P = 0.033). Compared to wild‐type genotype, the TT genotype was associated with increased risk for CIN development (OR: 5.7; 95% CI: 1.18–27.26; P = 0.033). Compared to controls, patients with CT and TT genotypes displayed increased TGF‐β1 levels in serum (P < 0.0001 and P = 0.0002, respectively) and BM (P < 0.0001 and P = 0.0002, respectively). No significant difference was found between patients and controls in the frequency of TNF‐α?308G/A, TGF‐β1 +869T/C and +915G/C and Fas‐L ‐844T/C polymorphisms. Conclusions: The TGF‐β1 ?509C/T polymorphism is associated with increased risk for CIN and contributes to the pathophysiology of the disorder by inducing TGF‐β1 overproduction. This is the first study providing evidence that genetic factors may predispose to CIN and may have a role in the pathophysiology of the disorder.     

Association of 29C>T polymorphism in the transforming growth factor‐β1 gene with lean body mass in community‐dwelling Japanese population

Aim: Sarcopenia is the significant degenerative loss of skeletal muscle mass and strength associated with aging, and it is one of the components of frailty. We previously reported an association between the 29C>T polymorphism in the transforming growth factor‐β1 gene (rs1800470) and the prevalence of vertebral fractures in subjects with postmenopausal osteoporosis. The association was not attributable to bone mineral density, which suggests that polymorphism influences some aspects of bone quality that affects strength and/or frailty rather than bone strength itself. Thus, we examined the relationship between genetic polymorphism and lean body mass in a Japanese population. Methods: A total of 479 adults comprising 143 men and 336 women, age 23 to 85 years, participated in the present study. Fat‐free mass was measured by dual energy X‐ray absorptiometry, and the relative skeletal muscle index was calculated as the ratio of appendicular (sum of arms and legs) fat‐free mass to the square of height. Results: Total, leg, and appendicular fat‐free mass as well as the relative skeletal muscle index were significantly lower in male subjects with CT/TT genotypes compared to those with CC genotype. Female subjects did not show any genotype‐dependent differences when analyzed as a group, but when those without menstruation (postmenopausal women) were analyzed, arm fat‐free mass was significantly lower in the CT/TT genotypes than in the CC genotype. Conclusions: T allele of the 29C>T polymorphism in the transforming growth factor‐β1 gene might be a risk factor of sarcopenia in a Japanese population. Geriatr Gerontol Int 2012; 12: 292–297.     

Prognostic value of hypoxia inducible factor 1α in esophageal squamous cell carcinoma

Hypoxia inducible factor 1α (HIF 1α) plays a major role in the pleitropic response observed secondary to hypoxic conditions in tumors. Its expression in the tumor cells has been correlated to tumor aggressiveness and prognosis in squamous cell carcinoma (SCC) of the esophagus in Far Eastern population, but limited information is available on the prognostic role of HIF 1α in SCC of esophagus in European population. This information may help in choosing appropriate therapeutic strategies and possibly developing a monoclonal antibody with therapeutic potential targeting the HIF 1α. Tumor samples from 36 patients diagnosed with SCC of the esophagus were collected. Prepared tissue sections were stained with validated and specific monoclonal antibodies for HIF 1α and the expression was correlated with the disease pattern and survival. Out of 36 patients, 17 patients showed low and 19 high expression of HIF 1α. There was no difference in the disease‐free and overall survival between these two groups (P > 0.05, log rank test). Regression analysis showed that HIF 1α was not an independent prognostic factor for survival (P > 0.05). HIF 1α did not show prognostic value in SCC of the esophagus in our study on European population, in agreement with previous studies. Novel strategies on the therapeutic manipulation of HIF 1α in cancer are to be explored further and may have a role to play in improving treatment outcome.