Acquired Multidrug Resistance in AML Is Caused by Low Apoptotic Priming in Relapsed Myeloblasts.

In many cancers, mortality is associated with the emergence of relapse with multidrug resistance (MDR). Thus far, the investigation of cancer relapse mechanisms has largely focused on acquired genetic mutations. Using acute myeloid leukemia (AML) patient-derived xenografts (PDX), we systematically elucidated a basis of MDR and identified drug sensitivity in relapsed AML. We derived pharmacologic sensitivity for 22 AML PDX models using dynamic BH3 profiling (DBP), together with genomics and transcriptomics. Using in vivo acquired resistant PDXs, we found that resistance to unrelated, narrowly targeted agents in distinct PDXs was accompanied by broad resistance to drugs with disparate mechanisms. Moreover, baseline mitochondrial apoptotic priming was consistently reduced regardless of the class of drug-inducing selection. By applying DBP, we identified drugs showing effective in vivo activity in resistant models. This study implies evasion of apoptosis drives drug resistance and demonstrates the feasibility of the DBP approach to identify active drugs for patients with relapsed AML. SIGNIFICANCE: Acquired resistance to targeted therapy remains challenging in AML. We found that reduction in mitochondrial priming and common transcriptomic signatures was a conserved mechanism of acquired resistance across different drug classes in vivo. Drugs active in vivo can be identified even in the multidrug resistant state by DBP.

In-vitro and in-vivo investigation of amygdalin, metformin, and combination of both against doxorubicin on hepatocellular carcinoma.

AIM: Hepatocellular carcinoma (HCC) is a potentially life-threatening cancer. In the current study, anti-HCC efficacy of amygdalin, or metformin alone or in combination in comparison to doxorubicin was studied. MAIN METHODS: Both in-vitro and in-vivo based models. HepG-2 and Huh-7 cell lines as established in-vitro model for HCC were treated with different concentrations of indicated drugs to evaluate the cytotoxicity and determine IC50 for 24, 48 and 72 h. Moreover, the effect of different treatments on apoptosis and cell cycle using flow cytometric analysis were studied. Hepatocellular carcinoma induced in rats by diethyl-nitrosamine and carbon tetrachloride was established, to further investigate the efficacy of indicated drugs. Aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase were measured by spectrophotometer, alpha-fetoprotein, cytochrome-c, caspase-3 and malondialdehyde were measured by ELISA, and liver biopsies were also evaluated histopathologically. KEY FINDINGS: In-vitro results showed that the combination has a promising effect when compared to amygdalin or metformin alone as it is more cytotoxic and have higher ability for induction of apoptosis and arresting cell cycle. In-vivo doxorubicin has a good effect for treating HCC. Also, the combination showed a promising prognostic effect depending on the cytotoxic activity and tumor marker when compared to amygdalin or metformin alone. SIGNIFICANCE: Based on the current data, it was hypothesized that amygdalin and metformin especially when used in combination will be a promising approach with low side effects for enhancement of HCC.