Enhanced Urinary Bladder, Liver and Colon Carcinogenesis in Zucker Diabetic Fatty Rats in a Multiorgan Carcinogenesis Bioassay: Evidence for Mechanisms Involving Activation of PI3K Signaling and Impairment of p53 on Urinary Bladder Carcinogenesis

In the present study, modifying effects of diabetes on carcinogenesis induced in type 2 diabetes mellitus model Zucker diabetic fatty (ZDF) rats were investigated using a multiorgan carcinogenesis bioassay. Our re sults demonstrated enhancement of urinary bladder, colon and liver carcinogenesis in ZDF rats treated with five types of carcinogens (DMBDD). Elevated insulin and leptin and decreased adiponectin levels in the serum may be responsible for the high susceptibility of type 2 diabetes mellitus model rats to carcinogenesis in these organs. Possible mechanisms of increased susceptibility of diabetic rats to bladder carcinogenesis could be activation of the PI3K pathway and suppression of p53 in the urothelium in consequence of the above serum protein alterations.

The BH3 alpha-helical mimic BH3-M6 disrupts Bcl-X(L), Bcl-2, and MCL-1 protein-protein interactions with Bax, Bak, Bad, or Bim and induces apoptosis in a Bax- and Bim-dependent manner

A critical hallmark of cancer cell survival is evasion of apoptosis. This is commonly due to overexpression of anti-apoptotic proteins such as Bcl-2, Bcl-X(L), and Mcl-1, which bind to the BH3 α-helical domain of pro-apoptotic proteins such as Bax, Bak, Bad, and Bim, and inhibit their function. We designed a BH3 α-helical mimetic BH3-M6 that binds to Bcl-X(L) and Mcl-1 and prevents their binding to fluorescently labeled Bak- or Bim-BH3 peptides in vitro. Using several approaches, we demonstrate that BH3-M6 is a pan-Bcl-2 antagonist that inhibits the binding of Bcl-X(L), Bcl-2, and Mcl-1 to multi-domain Bax or Bak, or BH3-only Bim or Bad in cell-free systems and in intact human cancer cells, freeing up pro-apoptotic proteins to induce apoptosis. BH3-M6 disruption of these protein-protein interactions is associated with cytochrome c release from mitochondria, caspase-3 activation and PARP cleavage. Using caspase inhibitors and Bax and Bak siRNAs, we demonstrate that BH3-M6-induced apoptosis is caspase- and Bax-, but not Bak-dependent. Furthermore, BH3-M6 disrupts Bcl-X(L)/Bim, Bcl-2/Bim, and Mcl-1/Bim protein-protein interactions and frees up Bim to induce apoptosis in human cancer cells that depend for tumor survival on the neutralization of Bim with Bcl-X(L), Bcl-2, or Mcl-1. Finally, BH3-M6 sensitizes cells to apoptosis induced by the proteasome inhibitor CEP-1612.

Expression and translocation of aquaporin-2 in the endolymphatic sac in patients with Meniere's disease

Meniere's disease, characterised by episodic vertigo, fluctuating hearing loss and tinnitus, can occur under conditions of stress. Its pathology was first revealed to be inner ear hydrops through temporal bone studies in 1938. Although its pathogenesis has been proposed to be a disorder of water transport in the inner ear, subsequently, it remains unsolved, until now. A recent study revealed that both plasma stress hormone, vasopressin (pAVP) and its receptor, V2 (V2R) expression in the inner ear endolymphatic sac were significantly higher in Meniere's patients. In the present study, to link V2R-related molecules and inner ear hydrops, we examined V2R-linked water channel molecule, aquaporin-2 (AQP2) expression and translocation in human endolymphatic sac. AQP2 mRNA expression in the endolymphatic sac was significantly higher in Meniere's patients by using real-time polymerase chain reaction, as further confirmed by western blotting. AQP2-like immunoreactivity (-LIR) was translocated from luminal to basolateral side with endosomal trapping in the endolymphatic sac at the time of AVP exposure in human endolymphatic sac tissue culture. The similar AQP2-LIR translocation was also demonstrated by forskolin and blocked by vasopressin/V2R specific antagonist, OPC31260 and protein kinase A (PKA) specific antagonists, H-89 and KT-5720. We concluded that in the pathogenesis of inner ear hydrops resulting in Meniere's attacks, pAVP elevation as a result of stress and subsequent V2R-cAMP-PKA-AQP2 activation and endosomal trapping of AQP2 in the endolymphatic sac, might be important as a basis of this disease. Further experimental and clinical studies are needed to better clarify the neuroscientific relationship between stress and Meniere's disease.

Experimental encephalomyocarditis virus infection in small laboratory rodents

Encephalomyocarditis virus (EMCV) is a cardiovirus that belongs to the family Picornaviridae. EMCV is an important cause of acute myocarditis in piglets and of fetal death or abortion in pregnant sows. Small rodents, especially rats, have been suspected to be reservoir hosts or carriers. This virus also induces type 1 diabetes mellitus, encephalomyelitis, myocarditis, orchitis and/or sialodacryoadenitis in small laboratory rodents. This paper reviews the pathology and pathogenesis of experimental infection with EMCV in small laboratory rodents.

Enhanced initial bone regeneration with inorganic polyphosphate-adsorbed hydroxyapatite

Inorganic polyphosphate (poly(P)) can promote binding between fibroblast growth factors and their receptors and enhance osteoblastic cell differentiation and calcification. This study evaluated the possibilities for poly(P) adsorbed onto interconnected porous calcium hydroxyapatite (IP-CHA) as a new bone regeneration material. Prepared 1%, 5%, 25% and 50% poly(P)/IP-CHA composites showed the elution peak of poly(P) between 15 and 20 min, respectively, with the highest value from 50% poly(P)/IP-CHA in vitro. Histologically, at 1 week of placement into the femur of rabbits, granulation tissue had penetrated into the pores in all composites and IP-CHA as a control. In contrast, at 2 weeks of placement, newly formed lamellar bone was found in all groups, although a higher amount of bone regeneration was obviously formed in the 25% and 50% poly(P)/IP-CHA with a significantly higher value of bone regeneration ratio of 50% poly(P)/IP-CHA. These results indicate that 25% and 50% poly(P)/IP-CHA composites may enhance initial bone regeneration.

Etoposide induces G2/M arrest and apoptosis in neural progenitor cells via DNA damage and an ATM/p53-related pathway

Etoposide (VP-16), an anti-tumor agent, is a topoisomerase II inhibitor that causes DNA damage. In our previous studies, it was shown that VP-16 induces S-phase accumulation and G2/M arrest, eventually resulting in apoptosis, through p53-related pathway in the mouse fetal brain. We injected 4 mg/kg of VP-16 into pregnant mice on day 12 of gestation, and the fetuses were investigated for the cell cycle checkpoint and mechanism of apoptosis. The transition of the neural progenitor cells in the fetuses was delayed as compared to that in the control, and most of the apoptotic cells were BrdU positive. VP-16-induced S-phase accumulation was brought about by the acceleration of G1/S transition rather than by the inhibition of S-phase progression. Phosphorylation of ataxia telangiectasia-mutated kinase (ATM) at Ser1981 and gammaH2AX after VP-16 treatment showed DNA damage. p53 was phosphorylated at Ser15 and 20 and increased after activation of the ATM kinase pathway. Cdc25A degradation might induce the inhibition of S-phase progression. It is supposed that an increase in cyclin A might accelerate G1/S progression. It is also indicated that VP-16-induced G2/M arrest is caused by p21, which inactivates cyclin B-Cdc2 complex and eventually prevents mitotic entry. In p53-deficient fetal brains, G2/M and apoptosis were almost abrogated, although S-phase accumulation still occurred. It is suggested that VP-16 induced p53-independent S-phase accumulation, and p53-dependent G2/M arrest and apoptosis of the neural progenitor cells in fetal mouse brain.

Abstract 732: Targeting the Bcl-2/BH3 protein-protein interaction: Identification, design, and synthesis of new selective inhibitors of the Mcl-1/BH3 interaction

It is well accepted that escape of apoptosis is a major mechanism for cancer progression and drug resistance. Anti-apoptotic members of the Bcl-2 protein family, such as Bcl-2, Bcl-xL and Mcl-1, are among the most effective inhibitors of apoptosis and are frequently upregulated in various types of human cancer. A number of pro-apoptotic proteins share only the BH3 domain with other members of the Bcl-2 family, so called BH3-only proteins, and appear to function essentially as transdominant inhibitors by binding to anti-apoptotic Bcl-2 family proteins and neutralizing their cell-survival activity. The development of small molecules to mimic the BH3 proteins has been an intense area of research. It is clear from the development of ABT737 (and its orally available relative ABT-263) that targeting of Bcl-2/Bcl-xL by small molecule BH3-mimetics is a promising strategy for the development of a new class of anticancer drugs. However the clinical potential of ABT737 may be limited since it does not inhibit the pro-survival Bcl-2 family protein Mcl-1. To date available Bcl-2 family proteins inhibitors are either pan-inhibitors such as (-)-gossypol (which simultaneously inhibits Bcl-xl/BH3, Bcl-2/BH3 and Mcl-1/BH3 interactions) or are selective for the Bcl-xl/BH3 and Bcl-2/BH3 interactions. Hence a selective Mcl-1/BH3 inhibitor would greatly aid investigating the role of Mcl-1 in cancer and in drug resistance and complement the activity of ABT737. Our current study is centered on the identification and the synthesis of small molecule selective inhibitors of the Mcl-1/BH3 interaction. To this aim we interrogated the hit-list from inhibitors of the MLSCN screen of the Mcl-1-NOXA interaction [(Emory, AID 1022) TR-FRET screen for Mcl-1-NOXA inhibitors]. We docked 2100 of the experimental 2100 MLSCN hits with Mcl-1 protein structure derived from the Mcl-1-NOXA X-ray crystal structure. We then examined the top 375 compounds. We then ranked them by docking score, the number of MLSCN biological assays tested and number of hits in these assays. We then selected compounds that docked well and had been tested in many MLSCN assays for which they were not hits. Selected compounds were purchased and assessed for activity in an Alphascreen and ELISA assay, to reveal the hit HL5-026 (IC50 = 46 µM). HL5-026 is an inhibitor of the Mcl-1/Bim-BH3 interaction that has four-fold selectivity over Bcl-xl/Bim-BH3. HL5-026 binding to Mcl-1 is currently being assessed via co-crystallization and other biophysical techniques. We will report the synthesis and biological evaluation of focused libraries based on the initial hit and designed by modeling and docking to Mcl-1. First generation libraries have revealed compounds of improved activity. Structure activity relationships around the hits will be disclosed as well as the outcomes of further rounds of chemical design and biological assessment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 732.

Potassium bromate enhances N-ethyl-N-hydroxyethylnitrosamine-induced kidney carcinogenesis only at high doses in Wistar rats: indication of the existence of an enhancement threshold

As susceptibility to carcinogens varies considerably among different strains of experimental animals, evaluation of dose-response relationships for genotoxic carcinogen in different strains is indispensable for risk assessment. Potassium bromate (KBrO(3)) is a genotoxic carcinogen inducing kidney cancers at high doses in male F344 rats, but little is known about its carcinogenic effects in other strains of rats. The purpose of the present study was to determine dose-response relationships for carcinogenic effects of KBrO(3) on N-ethyl-N-hydroxyethylnitrosamine (EHEN)-induced kidney carcinogenesis in male Wistar rats. We found that KBrO(3) showed significant enhancement effects on EHEN-induced kidney carcinogenesis at above 250 ppm but not at doses of 125 ppm and below when evaluated in terms of induction of either preneoplastic lesions or tumors in male Wistar rats. Furthermore, KBrO(3) significantly increased the formation of oxidative DNA damage at doses of 125 and above but not at doses of 30 ppm and below in kidneys. These results demonstrated that low doses of KBrO(3) exert no effects on development of EHEN-initiated kidney lesions and induction of oxidative DNA damage. Taking account of previous similar findings in male F344 rats, it is strongly suggested that a threshold dose exists for enhancement effects of KBrO(3) on kidney carcinogenesis in rats.

Effect of combined application of bFGF and inorganic polyphosphate on bioactivities of osteoblasts and initial bone regeneration

Basic fibroblast growth factor (bFGF) and inorganic polyphosphate (poly(P)) have been recognized as therapeutic agents that enhance bone regeneration. It has also been shown that poly(P) may enhance the mitogenic activity of bFGF. The purpose of this study is to evaluate the combined effect of bFGF and poly(P) on bioactivities of osteoblasts and initial bone regeneration in vitro and in vivo. MC3T3-E1 cells were treated with bFGF, poly(P) or bFGF+poly(P), then subjected to cell proliferation assay, alkaline phosphatase (ALP) activity measurement, quantitative real-time reverse transcription-polymerase chain reaction and Alizarin S Red staining. In an in vivo study, bFGF-, poly(P)- and bFGF+poly(P)-modified interconnected porous hydroxyapatite (IPHA) complexes were fabricated, and placed into the femurs of rabbits to evaluate new bone formation histologically and histomorphometrically. The highest enhancement of cell proliferation were observed in those treated with bFGF+poly(P) on days 5 and 7. Cells treated with bFGF+poly(P) also exhibited increased ALP activity on days 5 and 10, up-regulated mRNA levels of osteocalcin and osteopontin, and enhanced calcification when compared to the non-treated cells. In vivo, the highest bone formation ratio was observed in bFGF+poly(P)-modified IPHA complexes. This study indicated that co-application of bFGF and poly(P) may provide enhanced bone formation by modulating cell proliferation and the mineralization process. It is anticipated that a combined application of bFGF and poly(P) can provide a novel method for bone regeneration in clinical use.

Increased risk of exacerbating gastrointestinal disease among elderly patients following treatment with calcium channel blockers

BACKGROUND AND OBJECTIVE

Calcium channel blockers (CCBs) have been widely used for the treatment of hypertension and angina pectoris. It is presumed that CCBs decrease the lower esophageal sphincter pressure and as a result, the risk of gastrointestinal disease may be increased. Since the prevalence of gastrointestinal diseases has increased in elderly patients, it is possible that treatment with CCBs may have contributed to this increase. Therefore, we considered that the risk of exacerbating gastrointestinal disease among elderly patients by CCBs can be estimated by using the prescription ratio of antisecretory drugs as an outcome.

METHOD

We hypothesized that patients who are prescribed CCBs would increase the use of antisecretory drugs involving H(2)-receptor antagonists and proton pump inhibitors (PPIs). From January 2001 to December 2005, a dynamic retrospective cohort study was performed at three community pharmacies in Nagasaki city, Japan, to assess the use of antisecretory drugs following treatment with CCBs among elderly patients. The correlation of initiation of antisecretory drugs treatment to maintenance therapy with PPIs was determined by the Cox proportional hazards model.

RESULTS

The proposed study includes 303 patients prescribed CCBs and 258 controls. During the study period, 138 patients prescribed CCBs and 66 controls were initiated by giving antisecretory drugs; the hazard ratio was 1.40 (95% confidence interval 1.21-1.63). Eighty two patients taking CCBs and 32 controls were initiated by the maintenance therapy with PPIs; the hazard ratio was 1.48 (95% confidence interval 1.21-1.83).

CONCLUSION

Patients who simultaneously initiated the use of antisecretory drugs with CCBs could not be found. Therefore, antisecretory drugs have not been used to prevent the gastrointestinal diseases caused by CCBs. The results obtained in this study suggest that the risk of gastrointestinal disease could be increased by long-term treatment with CCBs for elderly patients.

Meniere's attacks occur in the inner ear with excessive vasopressin type-2 receptors

Meniere's disease is peculiar to humans and is characterised by episodic vertigo, fluctuating hearing loss and tinnitus, and attacks of the affliction occurring under conditions of stress. Its pathology was first revealed to be inner ear hydrops through temporal bone studies in 1938. Although subsequently proposed as a disorder of water metabolism in the inner ear, its pathogenesis remains unsolved. The present study aimed to assess the link between the inner ear pathology in Meniere's disease and vasopressin, an anti-diuretic stress hormone with a potential role in inner ear fluid homeostasis. Blood samples were obtained from Meniere's disease patients in the morning, before any surgical treatment, to examine plasma vasopressin (pAVP) levels, and then from inner ear tissue during surgical treatment, to examine vasopressin type-2 receptor (V2R) in the endolymphatic sac. pAVP and the relative V2R mRNA expression in the endolymphatic sac were examined using a real-time polymerase chain reaction. Relative cAMP activity in the endolymphatic sac was also examined using tissue culture and cAMP assay. Both pAVP (1.6-fold versus controls; P = 0.048) and inner ear V2R mRNA expression (41.5-fold versus controls; P = 0.022) were significantly higher in Meniere's patients. cAMP activity was basally up-regulated (2.1-fold versus controls) and cAMP sensitivity to vasopressin application was largely elevated (4.9-fold versus controls) in Meniere's patients. We conclude that, in the pathogenesis of inner ear hydrops, resulting in Meniere's attacks, elevation of pAVP levels (probably as a result of stress) may present as a matter of consequence, but susceptibility of the V2R-overexpressed and cAMP-hypersensitized inner ear to pAVP elevation might be essential as the basis of this disease. Further experimental and clinical studies are needed to better clarify the relationship between Meniere's disease and stress.

Complementary Distributions of Amyloid-β and Neprilysin in the Brains of Dogs and Cats

Neprilysin is an amyloid-β-degrading enzyme localized in the brain parenchyma. The involvement of neprilysin in the pathogenesis of Alzheimer's disease has recently received much attention. We examined the localization of neprilysin and amyloid-β, as well as the activity of neprilysin, in the brains of dogs and cats of various ages to clarify the relationship between neprilysin activity and amyloid-β deposition. The distribution of neprilysin was almost identical in dogs and cats, being high in the striatum, globus pallidus, and substantia nigra, but very low in the cerebral cortex. The white matter and hippocampus were negative. Neprilysin activity in the brain regions in dogs and cats was ranked from high to low as follows: thalamus/striatum > cerebral cortex > hippocampus > white matter. Amyloid-β deposition was first detected at 7 and 10 years of age in dogs and cats, respectively, and both the quantity and frequency of deposition increased with age. In both species, amyloid-β deposition appeared in the cerebral cortex and the hippocampus. In summary, the localization of neprilysin and neprilysin activity, and that of amyloid-β, were complementary in the brains of dogs and cats.

Unilateral optical nerve hypoplasia in a Beagle dog

Unilateral (left eye) optic nerve hypoplasia was detected in a six-month-old male Beagle dog. Vision testing indicated that the left eye had poor vision and testing the pupillary light reflex showed the left eye to have an absence of the afferent pathway of the reflex but it had a normal efferent pathway. Ophthalmoscopy revealed a small-sized optic disc, winding retinal artery and dilated retinal vasculature in the left globe. Electroretinography showed no abnormal findings even in the left globe. Histopathologically, the left optic nerve was markedly hypoplastic and was composed of sparse neural elements and a moderate amount of connective and glial tissues. In the retina of the left globe, the nerve fibre layer and the ganglion cell layer were reduced in thickness, although a small number of ganglion cells were still present. There were no abnormal findings detected in the right globe and the right optic nerve. The brain appeared normal macroscopically.

Management of total paralysis of the brachial plexus by the double free-muscle transfer technique

The double free-muscle transfer technique achieved a dramatic revolution in the treatment of total paralysis of the brachial plexus by providing universal prehensile function, although several requirements such as successful free-muscle transfers, stability of the proximal joints and prolonged postoperative rehabilitation are necessary for the success of this procedure. To obtain the best outcome of double free-muscle transfer, it is imperative to understand the key factors, viz. selection of the donor muscle, meticulous microsurgical technique, importance of proximal joint stability, selection of the kind of grip and postoperative rehabilitation. Double free-muscle transfer is not a simple microsurgical muscle transfer for finger movement, but a universal reconstructive procedure for total paralysis of the upper limb.