Gaucher disease is an autosomal recessive lysosomal storage disorder caused by the deficient activity of glucocerebrosidase. Accumulation of glucosylceramide, primarily in the lysosomes of cells of the reticuloendothelial system, leads to hepatosplenomegaly, anemia and skeletal lesions in type I disease, and neurologic manifestations in types II and III disease. We report herein the identification of hydrophilic active‐site‐specific chaperones that are capable of increasing glucocerebrosidase activity in the cultured fibroblasts of Gaucher patients. Screening of a variety of natural and synthetic alkaloid compounds showed isofagomine, N ‐dodecyl deoxynojirimycin, calystegines A 3 , B 1 , B 2 and C 1 , and 1,5‐dideoxy‐1,5‐iminoxylitol to be potent inhibitors of glucocerebrosidase. Among them, isofagomine was the most potent inhibitor of glucocerebrosidase in vitro , and the most effective active‐site‐specific chaperone capable of increasing residual glucocerebrosidase activity in fibroblasts established from Gaucher patients with the most prevalent Gaucher disease‐causing mutation (N370S). Intracellular enzyme activity increased approximately two‐fold after cells had been incubated with isofagomine, and the increase in glucocerebrosidase activity was both dose‐dependent and time‐dependent. Western blotting demonstrated that there was a substantial increase in glucocerebrosidase protein in cells after isofagomine treatment. Immunocytochemistry revealed an improvement in the glucocerebrosidase trafficking pattern, which overlaps that of lysosome‐associated membrane protein 2 in Gaucher fibroblasts cultivated with isofagomine, suggesting that the transport of mutant glucocerebrosidase is at least partially improved in the presence of isofagomine. The hydrophilic active‐site‐specific chaperones are less toxic to cultured cells. These results indicate that these hydrophilic small molecules are suitable candidates for further drug development for the treatment of Gaucher disease.
Patients with esophageal squamous cell carcinoma (ESCC) might have a specific mechanism for the carcinogenesis by alcohol consumption in the background esophageal mucosa, and nuclear factor erythroid 2-related factor 2 (NRF2), which plays a protective role against esophageal carcinogenesis, and barrier dysfunction might be associated with this phenomenon. This study aimed to confirm this hypothesis. Twenty patients with superficial ESCCs (ESCC patients) and 20 age- and sex-matched patients without ESCC (non-ESCC patients) were enrolled. Biopsy samples were obtained from non-neoplastic esophageal mucosa: one for histological evaluation, one for quantitative real-time polymerase chain reaction (PCR), and two for the mini-Ussing chamber system to measure transepithelial electrical resistance (TEER) and, thereafter, for PCR. The TEER after acetaldehyde or both acetaldehyde and ethanol exposure did not differ significantly between ESCC and non-ESCC patients. Unlike non-ESCC patients, mRNA levels of NRF2 target genes and claudin4 in ESCC patients tended to decrease after the exposure, with a significant difference between no exposure and both acetaldehyde and ethanol exposure in NRF2 target genes (p < 0.05). Furthermore, in ESCC patients, the decreased tendency of mRNA levels of NRF2 target genes after the exposure was more pronounced in high-risk states, such as aldehyde dehydrogenase 2 (ALDH2) Lys alleles (Glu/Lys + Lys/Lys), Lugol-voiding lesion grade C, and drinking history. In conclusion, the protective role of NRF2 against carcinogenesis from alcohol exposure might be disrupted in the background esophageal mucosa of ESCC patients, which might lead to a high incidence of metachronous ESCC.
Although Helicobacter pylori (H. pylori) eradication has some inhibitory effects on the subsequent development of gastric cancer, there are sporadic cases of gastric cancer even after successful eradication. The pathogenesis of gastric cancer emerging after H. pylori eradication remains to be clarified. In this study, employing Congo-red chromoendoscopy, which is capable of visualizing the acid-secreting fundic mucosa, we investigated the topographic relationship of the acid secretion pattern to the occurrence site of gastric cancers emerging after eradication. Fourteen consecutive patients who suffered from new gastric cancer after eradication, defined as lesions that were discovered at least 2 years after the eradication, were prospectively enrolled. Whether the neoplasias arose from acid-secreting or non-acid-secreting areas was evaluated with Congo-red chromoendoscopy. Biopsy specimens taken from the two areas were subjected to histologic evaluation and immunohistochemistry for Ki-67 and p53. The mean period from the eradication to the subsequent occurrence of gastric cancer was 74 (44) months. There were two cancer lesions in 5 cases, and thus there was a total 19 lesions from 14 cases. Congo-red chromoendoscopy revealed that all 19 lesions arose exclusively from non-acid-secreting areas. Histological examination revealed sustained hyperproliferation and accumulation of p53 protein was frequently detectable in non-acid-secreting areas. Genetic alteration such as p53 mutation seems to be already present in the residual non-acid-secreting areas after eradication, areas that could be the origin of gastric carcinogenesis after eradication. Identification of such high-risk areas should be a promising approach for estimating the individual cancer risk after eradication.
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