Anti-NO2-Tyrosine polyclonal antibody

Chronic myeloid leukemia is driven by the BCR-ABL oncoprotein, a constitutively active protein tyrosine kinase. Although tyrosine kinase inhibitors (TKIs) have greatly improved the prognosis of CML patients, the emergence of TKI resistance is an important clinical problem, which deserves additional treatment options based on unique biological properties to CML cells. In this study, we show that metabolic homeostasis is critical for survival of CML cells, especially when the disease is in advanced stages. The BCR-ABL protein activates AMP-activated protein kinase (AMPK) for ATP production and the mTOR pathway to suppress autophagy. BCR-ABL is detected in the nuclei of advanced-stage CML cells, in which ATP is sufficiently supplied by enhanced glucose metabolism. AMP-activated protein kinase is further activated under energy-deprived conditions and triggers autophagy through ULK1 phosphorylation and mTOR inhibition. In addition, AMPK phosphorylates 14-3-3 and Beclin 1 to facilitate cytoplasmic translocation of nuclear BCR-ABL in a BCR-ABL/14-3-3 tau/Beclin1/XPO1 complex. Cytoplasmic BCR-ABL protein undergoes autophagic degradation when intracellular ATP is exhausted by disruption of the energy balance or forced autophagy flux with AMP mimetics, mTOR inhibitors, or arsenic trioxide, leading to apoptotic cell death. This pathway represents a novel therapeutic vulnerability that could be useful for treating TKI-resistant CML.

Background TAPUR is a pragmatic, phase II basket study evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancers harboring genomic alterations known to be drug targets. Sunitinib is an oral multikinase inhibitor ofFMS-like tyrosine kinase-3(FLT-3), among other targets. Results from a cohort of patients with metastatic colorectal cancer (mCRC) withFLT-3amplification treated with sunitinib are reported. Objective This study aimed to investigate whether patients with mCRC withFLT-3amplification would be responsive to sunitinib, an oral multikinase inhibitor. Methods Eligible patients received a standard sunitinib dose of 50 mg orally for 4 weeks followed by 2 weeks off. Simon's two-stage design was used with the primary study endpoint of objective response (OR) or stable disease (SD) at 16 weeks based on Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1. Secondary endpoints were progression-free survival, overall survival, and safety. Results Ten patients were enrolled from November 2016 to April 2018. All patients had mCRC withFLT-3amplification. No ORs were observed. Although two patients had SD at 16 weeks, one died because of disease progression shortly thereafter and the cohort was closed. A single grade 3 adverse event of diarrhea was reported as possibly related to sunitinib. Conclusions Monotherapy with sunitinib does not have clinical activity in patients with mCRC withFLT-3amplification and should not be prescribed for off-label use. Other treatments should be considered for these patients, including treatments offered in clinical trials.