Targeting the Hedgehog Pathway Using Itraconazole to Prevent Progression of Barrett's Esophagus to Invasive Esophageal Adenocarcinoma.

OBJECTIVE: The aim of the study was to investigate whether inhibition of Sonic Hedgehog (SHH) pathway would prevent progression of Barrett's Esophagus (BE) to esophageal adenocarcinoma. BACKGROUND: The hedgehog signaling pathway is a leading candidate as a molecular mediator of BE and esophageal adenocarcinoma (EAC). Repurposed use of existing off-patent, safe and tolerable drugs that can inhibit hedgehog, such as itraconazole, could prevent progression of BE to EAC. METHODS: The efficacy of itraconazole was investigated using a surgical rat reflux model of Barrett's Metaplasia (BM). Weekly intraperitoneal injections of saline (control group) or itraconazole (treatment group; 200 mg/kg) were started at 24 weeks postsurgery. Esophageal tissue was harvested at 40 weeks. The role of the Hh pathway was also evaluated clinically. Esophageal tissue was harvested after 40 weeks for pathological examination and evaluation of the SHH pathway by immunohistochemistry. RESULTS: BM was present in control animals 29 of 31 (93%) versus itraconazole 22 of 24 (91%). EAC was significantly lower in itraconazole 2 of 24 (8%) versus control 10 of 31 (32%), respectively (P = 0.033). Esophageal SHH levels were lower in itraconazole vs control (P = 0.12). In esophageal tissue from humans with recurrent or persistent dysplastic BE within 24 months of ablative treatment, strong SHH and Indian Hedgehog expression occurred in distal BE versus proximal squamous epithelium, odds ratio = 6.1 (95% confidence interval: 1.6, 23.4) and odds ratio = 6.4 (95% confidence interval: 1.2, 32.8), respectively. CONCLUSION: Itraconazole significantly decreases EAC development and SHH expression in a preclinical animal model of BM. In humans, BE tissue expresses higher SHH, Indian Hedgehog, and bone morphogenic protein levels than normal squamous esophageal epithelium.

Current insight in the localized insulin-derived amyloidosis (LIDA): clinico-pathological characteristics and differential diagnosis.

BACKGROUND: In diabetic patients, subcutaneous insulin injection may cause several types of injection site-related lesions, such as lipoatrophy, insulin-induced cutaneous lipohypertrophy (IICL), allergic reaction, and iatrogenic localized insulin-derived amyloidosis (LIDA). Among these complications, both IICL and LIDA present as tumor-like and slow growing lesions; and they may be confused with one another. The clinical implication and management of IICL and LIDA are different. LIDA causes poor blood glycemic controls due to inadequate absorption of the insulin. Thus, accurate diagnosis of the lesion is critical in diabetic patients. REVIEW OF LITERATURE: LIDA is an extremely rare complication and often overlooked, it is managed by a surgical intervention. Whereas, IICL is a common side effect and can be managed by a non-surgical approach. Furthermore, in long-standing diabetics, patients may develop hypertrophic cardiomyopathy, proteinuria, peripheral, and autonomic neuropathy; these symptoms can be mistaken for a systemic amyloidosis. It is also necessary to distinguish LIDA from the systemic amyloidosis, which requires a more aggressive systemic therapy. LIDA should also be distinguished from primary cutaneous amyloidosis, with high risk of progression to a systemic amyloidosis. In this effort we reviewed 25 published manuscripts, including case reports and case series studies. We also summarized the literature and discussed differential diagnosis, including the approach to diagnose LIDA. CONCLUSION: The identification of amyloid material and immunoreactivity with anti-insulin antibodies are key diagnostic features of LIDA. Although several clinical and animal studies were made in recent years, the lesion is still under-diagnosed and underreported. The clinical suspicion and knowledge of the lesion play a crucial role for the accurate diagnosis of LIDA. Surgical excision of the lesion can dramatically decrease insulin requirement and improve glycemic control.

Hsp70's RNA-binding and mRNA-stabilizing activities are independent of its protein chaperone functions.

Hsp70 is a protein chaperone that prevents protein aggregation and aids protein folding by binding to hydrophobic peptide domains through a reversible mechanism directed by an ATPase cycle. However, Hsp70 also binds U-rich RNA including some AU-rich elements (AREs) that regulate the decay kinetics of select mRNAs and has recently been shown to bind and stabilize some ARE-containing transcripts in cells. Previous studies indicated that both the ATP- and peptide-binding domains of Hsp70 contributed to the stability of Hsp70-RNA complexes and that ATP might inhibit RNA recruitment. This suggested the possibility that RNA binding by Hsp70 might mimic features of its peptide-directed chaperone activities. Here, using purified, cofactor-free preparations of recombinant human Hsp70 and quantitative biochemical approaches, we found that high-affinity RNA binding requires at least 30 nucleotides of RNA sequence but is independent of Hsp70's nucleotide-bound status, ATPase activity, or peptide-binding roles. Furthermore, although both the ATP- and peptide-binding domains of Hsp70 could form complexes with an ARE sequence from VEGFA mRNA in vitro, only the peptide-binding domain could recover cellular VEGFA mRNA in ribonucleoprotein immunoprecipitations. Finally, Hsp70-directed stabilization of VEGFA mRNA in cells was mediated exclusively by the protein's peptide-binding domain. Together, these findings indicate that the RNA-binding and mRNA-stabilizing functions of Hsp70 are independent of its protein chaperone cycle but also provide potential mechanical explanations for several well-established and recently discovered cytoprotective and RNA-based Hsp70 functions.