The ubiquitin-proteasome system is a major regulatory pathway of protein degradation and plays an important role in cellular division. Fbxw7 (or hCdc4), a member of the F-box family of proteins, which are substrate recognition components of the multisubunit ubiquitin ligase SCF (Skp1-Cdc53/Cullin-F-box-protein), has been shown to mediate the ubiquitin-dependent proteolysis of several oncoproteins including cyclin E1, c-Myc, c-Jun, and Notch. The oncogenic potential of Fbxw7 substrates, frequent allelic loss in human cancers, and demonstration that mutation of FBXW7 cooperates with p53 in mouse tumorigenesis have suggested that Fbxw7 could function as a tumor suppressor in human cancer. Here, we carry out an extensive genetic screen of primary tumors to evaluate the role of FBXW7 as a tumor suppressor in human tumorigenesis. Our results indicate that FBXW7 is inactivated by mutation in diverse human cancer types with an overall mutation frequency of ∼6%. The highest mutation frequencies were found in tumors of the bile duct (cholangiocarcinomas, 35%), blood (T-cell acute lymphocytic leukemia, 31%), endometrium (9%), colon (9%), and stomach (6%). Approximately 43% of all mutations occur at two mutational “hotspots,” which alter Arg residues (Arg⁴⁶⁵ and Arg⁴⁷⁹) that are critical for substrate recognition. Furthermore, we show that Fbxw7^Arg465 hotspot mutant can abrogate wild-type Fbxw7 function through a dominant negative mechanism. Our study is the first comprehensive screen of FBXW7 mutations in various human malignancies and shows that FBXW7 is a general tumor suppressor in human cancer. [Cancer Res 2007;67(19):9006–12]

Background End-stage liver disease is a medical problem with high morbidity and mortality. We have investigated the feasibility, safety, and efficacy of using autologous mesenchymal stem cells (MSCs) as a treatment. Methods Eight patients (four hepatitis B, one hepatitis C, one alcoholic, and two cryptogenic) with end-stage liver disease having Model for End-Stage Liver Disease score ≥10 were included. Autologous MSCs were taken from iliac crest. Approximately, 30–50 million MSCs were proliferated and injected into peripheral or the portal vein. Liver function and clinical features were evaluated at baseline and 1, 2, 4, 8, and 24 weeks after injection. Results Treatment was well tolerated by all patients. Liver function improved as verified by the Model for End-Stage Liver Disease score, which decreased from 17.9±5.6 to 10.7±6.3 (P<0.05) and prothrombin complex from international normalized ratio 1.9±0.4 to 1.4±0.5 (P<0.05). Serum creatinine decreased from 114±35 to 80±18 μmol/l (P<0.05). Serum albumin changed from 30±5 to 33±5 g/l and bilirubin from 46±29 to 41±31 μmol/l. No adverse effects were noted. Conclusion Our data show that MSCs injection can be used for the treatment of end-stage liver disease with satisfactory tolerability. Furthermore, this treatment may improve clinical indices of liver function in end-stage liver disease.

Akkermansia muciniphila , as a member of the gut microbiota, has been proposed as a next-generation probiotic. Liver fibrosis is the main determinant of liver dysfunction and mortality in patients with chronic liver disease.

Inflammatory bowel disease (IBD) is described as a relapsing condition with high morbidity and uncertain complex pathogenesis. The association of Mycobacterium avium ssp. paratuberculosis (MAP) with Crohn’s disease (CD) in human has been debated for decades, however there is no confirmed data to verify such relations in Iran. The aim of this study was to investigate risk factors and a possible role of MAP in Iranian patients with CD. Anti-MAP antibodies were detected in serum of IBD patients and subjects without IBD (nIBD) through ELISA; MAP DNA and viable MAP cells were identified in patients’ biopsies through nested PCR and direct culture methods, respectively. Principal component analysis (PCA) was used to investigate the risk factors in relation to IBD and MAP infection. Positivity for IS900 PCR was detected in 64% (n = 18) of CD, 33% (n = 10) of ulcerative colitis (UC) and 9.7% (n = 6) of nIBD samples. Live MAP cells were isolated from biopsies of 2 CD patients only. Among 28 patients with CD, 46% (n = 13) and 39% (n = 11) were positive for antibodies against MAP3865c133–141 and MAP3865c125–133 peptides, respectively, whereas much lower seroreactivity was detected in UC subjects accounting for 3% (n = 1) for MAP3865c133–141 and 16.7% (n = 5) for MAP3865c125–133. A high immune reactivity to MAP epitopes among CD patients was positively correlated with consumption of fast food meals and IBD familiarity. For both CD and UC, breastfeeding period and consumption of fruit/vegetables presented negative correlation with the presence of anti-MAP antibodies. This study provided evidences that high prevalence of MAP DNA and anti-MAP antibodies in CD patients is significantly associated with the development of CD. Despite the role of several factors contributing to IBD, the presence of MAP DNA and anti-MAP antibodies in Iranian CD patients highlights a possible transmission of MAP from animal-derived products to humans.