Selective pks+ Escherichia coli strains induce cell cycle arrest and apoptosis in colon cancer cell line

pks+ Escherichia coli (E. coli) triggers genomic instability in normal colon cells which leads to colorectal cancer (CRC) tumorigenesis. Previously, we reported a significant presentation of pks+ E. coli strains in CRC patients' biopsies as compared to healthy cohorts. In this work, using an in vitro infection model, we further explored the ability of these strains in modulating cell cycle arrest and activation of apoptotic mediators in both primary colon epithelial cells (PCE) and CRC cells (HCT-116). Sixteen strains, of which eight tumours and the matching non-malignant tissues, respectively, from eight pks+ E. coli CRC patients were subjected to BrDU staining and cell cycle analysis via flow cytometry, while a subset of these strains underwent analysis of apoptotic mediators including caspase proteins, cellular reactive oxygen species (cROS) and mitochondrial membrane potential (MMP) via spectrophotometry as well as proinflammatory cytokines via flow cytometry. Data revealed that all strains exerted S-phase cell cycle blockade in both cells and G2/M phase in PCE cells only. Moreover, more significant upregulation of Caspase 9, cROS, proinflammatory cytokines and prominent downregulation of MMP were detected in HCT-116 cells indicating the potential role of pks related bacterial toxin as anticancer agent as compared to PCE cells which undergo cellular senescence leading to cell death without apparent upregulation of apoptotic mediators. These findings suggest the existence of discrepancies underlying the mechanism of action of pks+ E. coli on both cancer and normal cell lines. This work propounds the rationale to further understand the mechanism underlying pks+ E. coli-mediated CRC tumorigenesis and cancer killing.

Comparative expression of pro-inflammatory and apoptotic biosignatures in chronic HBV-infected patients with and without liver cirrhosis

The interplay of immune mediators is paramount to optimal host anti-viral immune responses, especially against chronic hepatitis B virus (HBV) infection. Here, we investigated the dynamic changes in host immune responses in chronic HBV-infected individuals with and without liver cirrhosis by examining the signatures of apoptosis and plasma levels of pro-inflammatory cytokines, chemokines, and cytotoxic proteins. A total of 40 chronic HBV patients with and without liver cirrhosis were studied for plasma levels of immune mediators, and signatures of apoptosis in peripheral blood mononuclear cells (PBMCs). The intracellular concentrations of reactive oxygen species (ROS) in patients with chronic HBV with liver cirrhosis was relatively higher as compared to chronic HBV patients. The onset of apoptosis was sustained due to ongoing liver inflammation in concert with plasma TNF-α and IL-6 levels. Plasma VEGF was upregulated among chronic HBV patients with liver cirrhosis, whereas CCL2, CCL5 and granzyme B levels were down-regulated. High levels of ROS, IL-6 and TNF-α correlated with ongoing inflammation among chronic HBV patients with liver cirrhosis, which likely attributed to the expression of biosignatures of apoptosis and activation in immune cells.

Stingless Bee Honey and Honeybee Honey Characteristics in Relation to Anticancer Potential

Introduction: The composition of the honey depends on the intrinsic and extrinsic factors, including place of origin, the floral types, the season and the storage conditions. This study compared the anticancer potential, quality, antioxidant and phytochemical between unprocessed stingless bee honey (SBH) and honeybee honey (HBH) from the same environmental factors including place of nest, floral type (Acacia), harvesting month (August) and storage conditions (<5°C). Materials and methods: To measure quality, 5-hydroxymethylfurfural (HMF) and diastase activity were determined, followed by total phenolic content (TPC) and total flavonoid content (TFC) for phytochemicals. Antioxidant activity was assessed via 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Cytotoxicity towards cervical cancer cell line (HeLa) was measured using a 2-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay (IC50). Results: The results indicated that HBH exhibited significantly higher diastase activity (2.17 ± 0.07 DN), TPC (338.95 ± 3.49 mg GAE/kg), DPPH scavenging activity EC50 (80.06 mg/ml) and MTT activity IC50 (64.80 mg/ml) towards HeLa as compared to SBH with absence of diastase activity, TPC (250.60 ± 3.98 mg GAE/kg), DPPH scavenging activity EC50 (165.80 mg/ml) and MTT activity IC50 (75.76 mg/ml). However, there were no significant differences in HMF and TFC between HBH and SBH. Conclusion: Therefore, the present study found that HBH demonstrates better antioxidant capacity, anticancer potential and phenolic content as compared to SBH.

Cytotoxic Activity of Isoniazid Derivative in Human Breast Cancer Cells

BACKGROUND/AIM

Isoniazid is an antibiotic used for the treatment of tuberculosis. Previously, we found that the isoniazid derivative (E)-N'-(2,3,4-trihydroxybenzylidene) isonicotinohydrazide (ITHB4) could be developed as novel antimycobacterial agent by lead optimization. We further explored the ability of this compound compared to zerumbone in inhibiting the growth of MCF-7 breast cancer cells.

MATERIALS AND METHODS

Cytotoxicity was measured by the MTT assay and further confirmed via apoptosis, ROS, cell cycle, DNA fragmentation and cytokine assays.

RESULTS

ITHB4 demonstrated a lower IC₅₀ compared to zerumbone in inhibiting the proliferation of MCF-7 cells. ITHB4 showed no toxicity against normal breast and human immune cells. Apoptosis assay revealed that ITHB4, at a concentration equal to the IC₅₀, induces apoptosis of MCF-7 cells and cell cycle arrest at the sub-G1 and G₂/M phases. ITHB4 triggered accumulation of intracellular ROS and nuclear DNA fragmentation. Secretion of pro-inflammatory cytokines induced inflammation and potentially immunogenic cell death.

CONCLUSION

ITHB4 has almost similar chemotherapeutic properties as zerumbone in inhibiting MCF-7 growth, and hence provide the basis for further experiments in animal models.

Release of pro-inflammatory cytokines TNF-α, IFN-γ and IL-6 by Burkholderia pseudomallei- stimulated peripheral blood mononucleocytes of acute myeloid leukemia patients

Acute myeloid leukemia (AML) is a malignant disease progressed from abnormal production of immature myeloid cells, which is often associated with concurrent infections after diagnosis. It was widely established that infections are the major contributors to mortality in this group due to the prevalency of neutropenia. Gram-negative Burkholderia pseudomallei is the causative agent of melioidosis. This disease had been reported in several neutropenic cancer patients undergoing chemotherapy resulting in severe clinical presentations and high mortalities which is in need of critical attention. Studies show that cytokines are important mediators of melioidosis progression and low neutrophil counts are associated with progression of its severity. However, to date, there are no reports on cytokine production in neutropenic cancer patients who are prone to melioidosis. Hence, here we assessed the cytokine production in neutropenic AML patients by introducing B. pseudomallei to their peripheral blood mononuclear cell (PBMC) culture in vitro. We observed that inflammatory response related cytokines namely TNF-α, IFN-γ IL-6 and IL-10 were highly circulated in infected PBMCs suggesting that these cytokines may play important roles in the progression of severity in melioidosis infected neutropenic patients.