No abstract

Parkinson's disease (PD) is a progressive neurodegenerative disorder that is primarily characterized by the degeneration of dopaminergic neurons in the nigrostriatal pathway. Previous studies have demonstrated that chronic systemic exposure of Lewis rats to rotenone produced many features of PD, and cerebral tauopathy was also detected in the case of severe weight loss. The present study was designed to assess the neurotoxicity of rotenone after daily oral administration for 28 days at several doses in C57BL/6 mice. In addition, we examined the protective effects of 4-phenylbutyrate (4-PBA) on nigral dopamine (DA) neurons in rotenone-treated mice. 4-PBA was injected intraperitoneally daily 30 min before each oral administration of rotenone. Chronic oral administration of rotenone at high doses induced specific nigrostriatal DA neurodegeneration, motor deficits and the up-regulation of a-synuclein in the surviving DA neurons. In contrast to the Lewis rat model, cerebral tauopathy was not detected in this mouse model. 4-PBA inhibited rotenone-induced neuronal death and decreased the protein level of a-synuclein. These results suggest that this rotenone mouse model may be useful for understanding the mechanism of DA neurodegeneration in PD, and that 4-PBA has a neuroprotective effect in the treatment of PD.

Purpose ROS1 rearrangement leads to constitutive ROS1 activation with potent transforming activity. In an ongoing phase 1 trial, the ALK tyrosine kinase inhibitor (TKI) crizotinib shows remarkable initial responses in patients with non-small cell lung cancer (NSCLC) harboring ROS1 fusions; however, cancers eventually develop crizotinib resistance due to acquired mutations such as G2032R in ROS1. Thus, understanding the crizotinib resistance mechanisms in ROS1 rearranged NSCLC and identification of therapeutic strategies to overcome the resistance are required. Experimental Design The sensitivity of CD74-ROS1-transformed Ba/F3 cells to multiple ALK inhibitors was examined. Acquired ROS1 inhibitor resistant mutations in CD74-ROS1 fusion were screened by N-ethyl-N-nitrosourea mutagenesis with Ba/F3 cells. To overcome the resistance mutation, we performed high throughput drug screening with small molecular inhibitors and anticancer drugs used in clinical practice or being currently tested in clinical trials. The effect of the identified drug was assessed in the CD74-ROS1 mutant Ba/F3 cells and crizotinib resistant patient-derived cancer cells (MGH047) harboring G2032R mutated CD74-ROS1. Results We identified multiple novel crizotinib resistance mutations in the ROS1 kinase domain including the G2032R mutation. As the result of high-throughput drug screening, we found that the cMET/RET/VEGFR inhibitor cabozantinib (XL184) effectively inhibited the survival of CD74-ROS1-WT and resistant mutants harboring Ba/F3 and MGH047 cells. Furthermore, cabozantinib could overcome all the resistance by all newly identified secondary mutations. Conclusions We developed a comprehensive model of acquired resistance to ROS1 inhibitors in NSCLC with ROS1 rearrangement and identified cabozantinib as a therapeutic strategy to overcome the resistance.

In the present study, we investigated the role of the macrophage inflammatory protein-1alpha (MIP-1alpha) in the pathogenesis of neuropathic pain following partial sciatic nerve ligation (PSL) in mice. MIP-1alpha mRNA and its protein were dramatically up-regulated after PSL, and MIP-1alpha was localized on macrophages and Schwann cells in the injured sciatic nerve (SCN). PSL-induced long-lasting tactile allodynia and thermal hyperalgesia were prevented by the perineural injection of anti-MIP-1alpha (2ng). Intraneural (20ng) and perineural (100ng) injection of recombinant MIP-1alpha elicited tactile allodynia and thermal hyperalgesia in sham-operated limb. MIP-1alpha receptors (CCR1 and CCR5) mRNA and their proteins were also up-regulated in the SCN after PSL, and were localized on macrophages and Schwann cells. PSL-induced tactile allodynia was attenuated by perineural injection (0.2nmol) of siRNA against CCR1 and CCR5. On the other hand, PSL-induced thermal hyperalgesia was prevented by siRNA against CCR5, but not CCR1. Interleukin-1beta (IL-1beta) mRNA and its precursor protein in macrophages and Schwann cells were also up-regulated in the SCN after PSL, and PSL-induced neuropathic pain was prevented by the perineural injection of anti-IL-1beta (2ng). PSL-induced IL-1beta up-regulation was suppressed by anti-MIP-1alpha and siRNA against CCR1 and CCR5. Perineural injection of nicotine (20nmol), a macrophage suppressor, prevented PSL-induced neuropathic pain and suppressed MIP-1alpha and IL-1beta expressions. In conclusion, we propose a novel critical molecule MIP-1alpha derived from macrophages and Schwann cells that appears to play a crucial role in the development of neuropathic pain induced by PSL.