Distinct Differences in the Induction of Stimulus-mediated Superoxide Generation by Polymorphonuclear Neutrophils Isolated From Patients With Different Types of Leukemia

Background/Purpose: Accumulating literature has documented that there exists a distinct difference in nitro blue tetrazolium reduction capacity by the polymorphonuclear neutrophils (PMNs) from patients with different types of leukemia. The underlying mechanism associated with this observed phenomenon remains to be clarified. Methods: The production of O2−, monitored by a validated probe (lucigenin)-based ultraweak chemiluminescence, in resting and/or phorbol-1,2-myristate-1,3-acetate (PMA)- and zymosan-stimulated systems of various leukemic PMNs was measured. In parallel with these studies, we also quantified superoxide dismutase isozymes (Cu, Zn-SOD, Mn-SOD) from these isolated PMNs by established methods. Results: A marked increase was observed in O2− generation by the PMNs from patients with acute myeloid leukemia (AML), and chronic myeloid leukemia (CML), but not from patients with acute lymphocytic leukemia (ALL) when compared with controls either in the resting condition or after being stimulated by either PMA or zymosan. In parallel, we also quantified SOD isozyme activities and found that the total and CuZn-SOD of PMNs from AML were indeed significantly lower than either controls or ALL, implying that higher levels of O2− generation might result from a deficiency in this O2−-metabolizing enzyme. Conclusion: Our data suggest that a distinct difference in the capability of O2− generation under stimulated conditions between PMNs from ALL and AML (or CML) may be of potential taxonomic or even therapeutic usefulness. J Formos Med Asso

Is the Blood Donated by Habitual Nut Quid Chewers Suitable for Use in Transfusion?

Betel quid (BQ) chewing is a popular oral masticatory activity, and there are approximately 600 million BQ chewers worldwide. Although chewing BQ has been linked to the patho-genesis of oral cancer, leukoplakia, and oral submucous fibrosis. The question whether the mixed constituents present in areca nut, which may exert cytotoxic effects on red blood cells (RBCs), has never been addressed. Methods: Heparinized blood specimens were obtained with informed consent from healthy laboratory personnel. RBCs were separated with the standard procedure and adjusted to 10% hematocrit with PBS. Various concentrations of areca nut extract (ANE; 100–800 μg/mL) were added to these RBC preparations and incubated at 37°C for 4 hours. Two portions (0.4 mL each) of the incubated RBCs were then used for measuring osmotic deformability index and for observing RBC morphology with scanning electron microscopy. The remaining RBCs were used for determining membrane sulfhydryl groups and protein profiles by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Results: Blood incubated with various concentrations of ANE showed concentration-dependent decreases in osmotic deformability index and membrane sulfhydryl groups. Membrane protein profiles revealed a significant loss of the band 3 fraction, with the concomitant appearance of several new protein bands in the electropheretogram. Finally, drastic morphological changes of ANE-treated RBCs were observed. Conclusion: We suggest that to assure the quality of transfusion, the blood donated by a habitual BQ chewer should be used with caution because of its possible contamination with areca nut ingredients that may be cytotoxic to RBCs

A Novel Microtubule-Disrupting Agent Induces Endoplasmic Reticular Stress-Mediated Cell Death in Human Hepatocellular Carcinoma Cells

<div><p>Here, we present evidence of a novel microtubule-disrupting agent, N-deacetyl-N-(chromone-2-carbonyl)-thiocolchicine (TCD), exhibiting potent antitumor activity (with IC₅₀ values in the nanomolar range) against hepatocellular carcinoma cell lines. Cell cycle analysis revealed that TCD induced G₂/M cell-cycle arrest in a dose- and time-dependent manner in both Hep-J5 and Mahlavu HCC cell lines. TCD also induced a decrease in mitochondrial membrane potential (ΔΨm) and caused DNA damage. Mechanistically, TCD activated protein kinase RNA-like endoplasmic reticular kinase and several transcription factors, including activating transcription factor (ATF) 6, ATF4, ATF3, and the CCAAT-enhancer binding protein homologous protein. These data clearly demonstrate that the antitumor activity of TCD is mechanistically linked to its capacity to trigger both intrinsic and extrinsic apoptotic cell death via endoplasmic reticular stress pathway. The potent antitumor activity of TCD was similarly demonstrated in a hepatocellular carcinoma xenograft model, where 5 and 10 mg/kg doses of TCD significantly arrested Hep-J5 and Mahlavu tumor growth. Our finding suggests that TCD is a promising therapeutic agent against hepatocellular carcinoma; further translational assessment of its clinical usage is warranted.</p></div

A diagrammatic presentation depicting the interplay of diverse mechanistic pathways involved in TCD-induced apoptosis of human hepatocellular carcinoma cells by both microtubule disruption and ER stress.

<p>A diagrammatic presentation depicting the interplay of diverse mechanistic pathways involved in TCD-induced apoptosis of human hepatocellular carcinoma cells by both microtubule disruption and ER stress.</p

Therapeutic efficacy of formulated TCD against (A) Hep-J5 and (B) Mahlavu human hepatoma xenografts.

<p>Hepatoma cells were subcutaneously injected into mice. Mice were treated with saline, or 5 or 10 mg/kg TCD when the mean tumor diameter reached 5 mm. The difference in the mean tumor volume was statistically significant between saline- and TCD drug-treated mice (*<i>p</i><0.05; **<i>p</i><0.01).</p