in the occurrence and development of AD. Given the link between peripheral insulin resistance and tau pathology in streptozotocin- injected and db/db mouse models of diabetes, we fed high fat diet (HFD) to pR5 mice expressing P301L mutant human tau, with the aim of developing a new model with characteristics of obesity, T2DM and AD to mimic AD patients exacerbated by obesity and T2DM, an increasing trend in modern society. In our study, pR5 and C57BL/6 (WT) mice were randomly allocated to a standard diet (STD) or HFD for 30 weeks starting at 8 weeks of age. Food intake was measured weekly, body weight and fasting glucose levels were measured fortnightly, and a comprehensive behavioral test battery was performed to assess anxiety, depression and cognitive dysfunction. Glucose and insulin tolerance tests were performed after 30 weeks of HFD. We also investigated the effect of long term HFD on tau pathology in the brains of WT and P301L mice by performing western blotting of whole brain homogenates for total tau, phosphorylated tau at Ser396 and Thr231. Our results show that pR5 mice fed with HFD are more vulnerable to diet induced obesity compared to WT, especially with increasing age. In addition, pR5 mice on HFD developed glucose intolerance and insulin resistance. It was identified that long term HFD significantly aggravates depression like behavior and impairs cognitive function in pR5 mice, and also induces anxiety like behavior in both pR5 and WT mice. Long term HFD was also shown to aggravate tau hyperphosphorylation in pR5 transgenic mice, and increase total and hyperphosphorylated tau in WT mice. These results indicate that diet induced obesity of pR5 transgenic mice expressing P301L mutant human tau generates T2DM, and aggravates tau phosphorylation, and is therefore a model useful for investigations that seek to understand the relationships between AD, T2DM and obesity, and the underlying biochemical changes and mechanisms associated with metabolic disorders and AD tauopathy.

A series of 1,3,4-oxadiazole-1,2,3-triazole hybrids bearing different pharmacophoric moieties has been designed and synthesized. Their antiproliferative activity was evaluated against four human cancer cell lines (Panc-1, MCF-7, HT-29, and A-549) using the MTT (3-(4,5-dimethylthiazol-2-yl)−2,5-diphenyltetrazolium bromide) assay. The preliminary activity test displayed that the most active compounds, 6d, 6e, and 8a–e, suppressed cancer cell growth (GI₅₀ = 0.23–2.00 µM) comparably to erlotinib (GI₅₀ = 0.06 µM). Compounds 6d, 6e, and 8a–e inhibited the epidermal growth factor receptor tyrosine kinase (EGFR-TK) at IC₅₀ = 0.11–0.73 µM, compared to erlotinib (IC₅₀ = 0.08 ± 0.04 µM). The apoptotic mechanism revealed that the most active hybrid 8d induced expression levels of caspase-3, caspase-9, and cytochrome-c in the human cancer cell line Panc-1 by 7.80-, 19.30-, and 13-fold higher than doxorubicin. Also, 8d increased the Bax level by 40-fold than doxorubicin, along with decreasing Bcl-2 levels by 6.3-fold. Cell cycle analysis after treatment of Panc-1 cells with hybrid 8d revealed a high proportion of cell accumulation (41.53%) in the pre-G1 phase, indicating cell cycle arrest at the G1 transition. Computational docking of the 8d and 8e hybrids with the EGFR binding site revealed their ability to bind with EGFR similar to erlotinib. Finally, in silico absorption, distribution, metabolism, and excretion/pharmacokinetic studies for the most active hybrids are discussed.