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The present study is on the growth inhibitory effect of Withania somnifera methanolic leaf extract and its active component, withanolide on HL-60 promyelocytic leukemia cells. The decrease in survival rate of HL-60 cells was noted to be associated with a time dependent decrease in the Bcl-2/Bax ratio, leading to up regulation of Bax. Both the crude leaf extract and the active component activated the apoptotic cascade through the cytochrome c release from mitochondria. The activation of caspase 9, caspase 8 and caspase 3 revealed that caspase was a key mediator in the apoptotic pathway. DNA fragmentation analysis revealed typical ladders as early as 12h indicative of caspase 3 role in the apoptotic pathway. Flow cytometry data demonstrated an increase of sub-G1 peak upon treatment by 51% at 24h, suggesting the induction of apoptotic cell death in HL-60 cells.

Conventional solvent fractionation and bioactivity based target assays were used to identify a new anti-cancer molecule from Phyllanthus urinaria, a herbal medicinal plant used in South India. At each step of the purification process the different fractions that were isolated were tested for specific anti-proliferative activity by assays measuring the inhibition of [(3)H]thymidine incorporation, and trypan blue drug exclusion. The ethyl acetate fraction that contained the bioactivity was further purified and resolved by HPLC on a preparative column. The purity of each of the fractions and their bioactivity were checked. Fraction 3 demonstrated a single spot on TLC and showed maximum anti-proliferative activity. This fraction was further purified and the structure was defined as 7'-hydroxy-3',4',5,9,9'-pentamethoxy-3,4-methylene dioxy lignan using NMR and mass spectrometry analysis. The pure compound and the crude ethyl acetate fraction which showed anti-proliferative activities were examined for ability to target specific markers of apoptosis like bcl2, c-myc and caspases and for effects on telomerase. Four specific cancer cell lines HEp2, EL-1 monocytes, HeLa and MCP7 were used in this study. The results indicate that 7'-hydroxy-3',4',5,9,9'-pentamethoxy-3,4-methylene dioxy lignan was capable of inhibiting telomerase activity and also could inhibit bcl2 and activate caspase 3 and caspase 8 whose significance in the induction of apoptosis is well known. We believe that this compound could serve as a valuable chemotherapeutic drug after further evaluations., (Copyright 2002 Cancer Research UK)

The limited availability of human heart tissue and its complex cell composition are major limiting factors for the reliable testing of drug efficacy and toxicity. Recently, we developed functional human and pig heart slice biomimetic culture systems that preserve the viability and functionality of 300 μm heart slices for up to 6 days. Here, we tested the reliability of this culture system for testing the cardiotoxicity of anti-cancer drugs. We tested three anti-cancer drugs (doxorubicin, trastuzumab, and sunitinib) with known different mechanisms of cardiotoxicity at three concentrations and assessed the effect of these drugs on heart slice viability, structure, function and gene expression. Slices incubated with any of these drugs for 48 h showed diminished in viability as well as loss of cardiomyocyte structure and function. Mechanistically, RNA sequencing of doxorubicin-treated tissues demonstrated a significant downregulation of cardiac genes and upregulation of oxidative stress responses. Trastuzumab treatment downregulated cardiac muscle contraction-related genes consistent with its clinically known effect on cardiomyocytes. Interestingly, sunitinib treatment resulted in significant downregulation of angiogenesis-related genes, in line with its mechanism of action. Similar to hiPS-derived-cardiomyocytes, heart slices recapitulated the expected toxicity of doxorubicin and trastuzumab, however, slices were superior in detecting sunitinib cardiotoxicity and mechanism in the clinically relevant concentration range of 0.1-1 μM. These results indicate that heart slice culture models have the potential to become a reliable platform for testing and elucidating mechanisms of drug cardiotoxicity.

Abstract: Aberrant epigenetics play a key role in the onset and progression of acute myeloid leukemia (AML). Herein we report in silico modelling based development of a novel, protein-vorinostat nanomedicine exhibiting selective and superior anti-leukemic activity against heterogeneous population of AML patient samples (n=9), including refractory and relapsed cases, and three representative cell lines expressing CD34+/CD38− stem cell phenotype (KG-1a), promyelocytic phenotype (HL-60) and FLT3-ITD mutation (MV4-11). Nano-vorinostat having ~100nm size exhibited enhanced cellular uptake rendering significantly lower IC50 in AML cell lines and patient samples, and induced enhanced HDAC inhibition, oxidative injury, cell cycle arrest and apoptosis compared to free vorinostat. Most importantly, nanomedicine showed exceptional single-agent activity against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. Collectively, this epigenetics targeted nanomedicine appears to be a promising therapeutic strategy against various French-American-British (FAB) classes of AML. From the Clinical Editor: Through the use of a protein-vorinostat agent, exceptional single-agent activity was demonstrated against the clonogenic proliferative capability of bone marrow derived leukemic progenitors, while remaining non-toxic to healthy bone marrow cells. The studied epigenetics targeted nanomedicine approach is a promising therapeutic strategy against various French-American-British classes of acute myeloid leukemia. [Copyright &y& Elsevier]