Changes in pathological and biochemical findings of systemic tissue sites in familial amyloid polyneuropathy more than 10†years after liver transplantation.

OBJECTIVE: To elucidate the long-term effects of liver transplantation (LT) on familial amyloid polyneuropathy (FAP). METHODS: We investigated clinicopathological and biochemical characteristics of systemic tissues in four autopsied cases of FAP patients surviving more than 10 years after LT and seven autopsied cases without LT. For analysing the truncated form of transthyretin (TTR) in amyloid, we also employed specimens from additional 18 FAP patients. RESULTS: Several tissue sites such as the heart, tongue and spinal cord had moderate-to-severe amyloid deposits but other tissues showed no or mild amyloid deposition. Those findings seemed similar to those observed in senile systemic amyloidosis (SSA), a sporadic amyloidosis caused by wild-type (WT) TTR. Also, amyloid deposits in systemic tissue sites except for the spinal cord in patients after LT derived mostly from WT TTR secreted from the normal liver grafts. In addition, in non-transplantation patients, proportions of WT TTR seemed to be relatively high in those tissue sites in which patients after LT had severe amyloid deposition, which suggests that WT TTR tends to form amyloid in those tissue sites. Finally, although the truncation of TTR in amyloid deposits did not depend on undergoing LT, we elucidated the truncation of TTR occurred predominantly in patients from non-endemic areas of Japan, where FAP amyloidogenic TTR V30M patients are late onset and low penetrance, compared with patients from an endemic area of Japan. CONCLUSIONS: FAP may shift to systemic WT TTR amyloid formation after LT, which seems to be similar to the process in SSA. The truncation of TTR in amyloid deposits may depend on some genetic or environmental factors other than undergoing LT.

Sphingosine kinase 1 plays a role in the upregulation of CD44 expression through extracellular signal-regulated kinase signaling in human colon cancer cells.

Our previous study has shown that the activity and expression of sphingosine kinase (SPHK) regulated the sensitivity of human colon cancer cells to the chemotherapeutic oxaliplatin (L-OHP). In addition, the cancer stem cell marker CD44 increases cell resistance to anticancer drugs. Here, we use colon cancer cell lines to examine the relationship between SPHK1 activity and CD44 expression.CD44 expression was measured by western blotting and quantitative PCR in two human colon cancer cell lines: L-OHP-resistant RKO and L-OHP-sensitive HCT116. The regulation of CD44 by SPHK1 was examined by either blocking or overexpressing SPHK1 and by using an L-OHP-resistant HCT116 clone (HCT116-R).The levels of SPHK1, CD44, phosphorylated-Akt, and phosphorylated-extracellular signal-regulated kinase (ERK) were much higher in the RKO cells than in the HCT116 cells. The treatment of RKO cells with the SPHK inhibitor or SPHK1 silencing by RNA interference suppressed CD44 protein expression. SPHK1 and CD44 levels were much higher in HCT116-R cells compared with the parental HCT116 cells. Transfection of HCT116 cells with SPHK1 cDNA enhanced the expression of both CD44 and phosphorylated-ERK. The increase in the CD44 protein level was abolished by the inhibition of ERK phosphorylation. Treatment of RKO cells with the sphingosine-1-phosphate (S1P)2 receptor antagonist suppressed ERK phosphorylation and the expression of CD44 mRNA and protein. Exogenous stimulation with S1P increased ERK phosphorylation and CD44 protein expression in HCT116 cells, but treatment with an MEK inhibitor and S1P2 receptor antagonist blocked this effect.These findings indicate that SPHK1 and its product, S1P, contribute toward the regulation of CD44 protein expression through the ERK signaling pathway through S1P2 in human colon cancer cells.

Aged vervet monkeys developing transthyretin amyloidosis with the human disease-causing Ile122 allele: a valid pathological model of the human disease.

Mutant forms of transthyretin (TTR) cause the most common type of autosomal-dominant hereditary systemic amyloidosis. In addition, wild-type TTR causes senile systemic amyloidosis, a sporadic disease seen in the elderly. Although spontaneous development of TTR amyloidosis had not been reported in animals other than humans, we recently determined that two aged vervet monkeys (Chlorocebus pygerythrus) spontaneously developed systemic TTR amyloidosis. In this study here, we first determined that aged vervet monkeys developed TTR amyloidosis and showed cardiac dysfunction but other primates did not. We also found that vervet monkeys had the TTR Ile122 allele, which is well known as a frequent mutation-causing human TTR amyloidosis. Furthermore, we generated recombinant monkey TTRs and determined that the vervet monkey TTR had lower tetrameric stability and formed more amyloid fibrils than did cynomolgus monkey TTR, which had the Val122 allele. We thus propose that the Ile122 allele has an important role in TTR amyloidosis in the aged vervet monkey and that this monkey can serve as a valid pathological model of the human disease. Finally, from the viewpoint of molecular evolution of TTR in primates, we determined that human TTR mutations causing the leptomeningeal phenotype of TTR amyloidosis tended to occur in amino acid residues that showed no diversity throughout primate evolution. Those findings may be valuable for understanding the genotype-phenotype correlation in this inherited human disease.

Clinicopathological features of senile systemic amyloidosis: an ante- and post-mortem study.

Senile systemic amyloidosis is a common age-related amyloidosis that involves accumulation of wild-type transthyretin, with cardiac dysfunction being a predominant result. The importance of obtaining an accurate diagnosis of senile systemic amyloidosis has been increasingly recognized, so that novel treatments are being developed. However, the clinicopathological features of senile systemic amyloidosis remain to be completely understood. Here, we evaluated cardiac specimens from 181 consecutive post-mortem cases older than 40 years, including 6 cases of senile systemic amyloidosis, and 5 cases of familial amyloidotic polyneuropathy, which is a hereditary systemic amyloidosis caused by mutant forms of transthyretin. Furthermore, we studied ante-mortem clinicopathological findings of 11 senile systemic amyloidosis cases, in which 9 cases underwent gastrointestinal tract biopsy and/or subcutaneous tissue biopsy, at Kumamoto University Hospital. Of the autopsied cases of elderly Japanese (older than 80 years), 12% had senile systemic amyloidosis, with the percentage increasing with age. The occurrence of senile systemic amyloidosis in elderly Japanese patients was lower than that in previous reports, which suggests that a genetic background and/or environmental factor(s) may have important roles in the occurrence of senile systemic amyloidosis. Transthyretin amyloid deposits in familial amyloidotic polyneuropathy cases developed mainly in the pericardium and the surrounding muscle fascicles, whereas in cases with senile systemic amyloidosis the transthyretin amyloid deposits had a patchy plaque-like shape and developed mainly inside the ventricular wall. Biopsies from senile systemic amyloidosis patients evidenced amyloid deposits in 44% (4/9) of gastrointestinal tract and subcutaneous tissue samples combined. As myocardial biopsy may be dangerous for elderly people, the use of a combination of gastrointestinal tract and subcutaneous tissue biopsies may make diagnosis of senile systemic amyloidosis easier.

Zinc and its transporter ZIP6 are key mediators of breast cancer cell survival under high glucose conditions.

Recent studies have shown that hyperglycaemia is related to breast cancer progression; however, the mechanisms underlying the relationship between hyperglycaemia and breast cancer cell survival remain unknown. Here, we demonstrate that as compared to physiological glucose conditions, high glucose conditions promote a significant increase in MCF-7 cell survival under hypoxia. High glucose levels inhibit apoptosis and induce epithelial-to-mesenchymal transition, resulting in increased cell viability under hypoxic conditions. Moreover, high glucose-treated cells display significant increases in intracellular Zn2+ levels and reduction in mRNA expression of the zinc (Zn) transporter Zrt- and Irt-like protein 6 (ZIP6) in hypoxia. ZIP6 deficiency disturbs intracellular Zn2+ homeostasis, leading to increased cell survival in hypoxia and reduced E-cadherin expression, indicating that decreased ZIP6 expression is strongly associated with resistance to hypoxia.

High glucose level promotes migration behavior of breast cancer cells through zinc and its transporters.

BACKGROUND: The diabetes patients have been associated with an increased risk of mortality by breast cancer and there are difference between the breast cancer patients with diabetes, and their nondiabetic counterparts in the regimen choice and effects of breast cancer treatment. However, the pathophysiological relationships of diabetes and breast cancer have not yet been elucidated in detail. In this study, we investigate the breast cancer cell line, MCF-7 motility, which linked to invasion and metastasis, in high glucose level corresponding to hyperglycemia and the role of Zn and its transporter. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated the significant motility of MCF-7 cultured in hyperglycemic level (25 mM glucose) in comparison to normal physiological glucose level (5.5 mM glucose). The other hand, the osmotic control medium, 5.5 mM glucose with 19.5 mM mannitol or fructose had no effect on migratory, suggesting that high glucose level promotes the migration of MCF-7. Moreover, the activity of intracellular Zn(2+) uptake significantly increased in high glucose-treated cells in comparison to 5.5 mM glucose, and the mRNA expression of zinc transporters, ZIP6 and ZIP10, was upregulated in 25 mM glucose-treated cells. The deficiency of ZIP6 or ZIP10 and intracellular Zn(2+) significantly inhibited the high migration activity in 25 mM glucose medium, indicating that Zn(2+) transported via ZIP6 and ZIP10 play an essential role in the promotion of cell motility by high glucose stimulation. CONCLUSION/SIGNIFICANCE: Zinc and its transporters, ZIP6 and ZIP10, are required for the motility stimulated with high glucose level. These findings provide the first evidence proposing the novel strategies for the diagnosis and therapy of breast cancer with hyperglycemia.

Pathological changes long after liver transplantation in a familial amyloidotic polyneuropathy patient.

Liver transplantation (LT) reportedly prolongs the survival of patients with familial amyloidotic polyneuropathy (FAP), a fatal hereditary systemic amyloidosis caused by mutant transthyretin (TTR). However, what happens in systemic tissue sites long after LT is poorly understood. In the present study, we report pathological and biochemical findings for an FAP patient who underwent LT and died from refractory ventricular fibrillation more than 16 years after FAP onset. Our autopsy study revealed that the distributions of amyloid deposits after LT were quite different from those in FAP amyloidogenic TTR V30M patients not having had LT and seemed to be similar to those observed in senile systemic amyloidosis (SSA), a sporadic systemic amyloidosis derived from wild-type (WT) TTR. Our biochemical examination also revealed that this patient's cardiac and tongue amyloid deposits derived mostly from WT TTR. We propose that FAP patients after LT may suffer from SSA-like WT TTR amyloidosis in systemic organs.