A Novel Role for the Klebsiella pneumoniae Sap (Sensitivity to Antimicrobial Peptides) Transporter in Intestinal Cell Interactions, Innate Immune Responses, Liver Abscess, and Virulence.

Klebsiella pneumoniae is an important human pathogen causing hospital-acquired and community-acquired infections. Systemic K. pneumoniae infections may be preceded by gastrointestinal colonization, but the basis of this bacterium's interaction with the intestinal epithelium remains unclear. Here, we report that the K. pneumoniae Sap (sensitivity to antimicrobial peptides) transporter contributes to bacterial-host cell interactions and in vivo virulence. Gene deletion showed that sapA is required for the adherence of a K. pneumoniae blood isolate to intestinal epithelial, lung epithelial, urinary bladder epithelial, and liver cells. The ΔsapA mutant was deficient for translocation across intestinal epithelial monolayers, macrophage interactions, and induction of proinflammatory cytokines. In a mouse gastrointestinal infection model, ΔsapA yielded significantly decreased bacterial loads in liver, spleen and intestine, reduced liver abscess generation, and decreased mortality. These findings offer new insights into the pathogenic interaction of K. pneumoniae with the host gastrointestinal tract to cause systemic infection.

Oxidative stress-modulating drugs have preferential anticancer effects - involving the regulation of apoptosis, DNA damage, endoplasmic reticulum stress, autophagy, metabolism, and migration.

To achieve preferential effects against cancer cells but less damage to normal cells is one of the main challenges of cancer research. In this review, we explore the roles and relationships of oxidative stress-mediated apoptosis, DNA damage, ER stress, autophagy, metabolism, and migration of ROS-modulating anticancer drugs. Understanding preferential anticancer effects in more detail will improve chemotherapeutic approaches that are based on ROS-modulating drugs in cancer treatments.

Butanol-Partitioned Extraction from Aqueous Extract of Gracilaria tenuistipitata Inhibits Cell Proliferation of Oral Cancer Cells Involving Apoptosis and Oxidative Stress.

We have previously found that the aqueous extract of Gracilaria tenuistipitata (AEGT) and its partitioned fractions had antioxidant properties in biochemical assays. Although the butanol-partitioned fraction of AEGT (AEGT-pBuOH) had a stronger antioxidant performance than AEGT, its biological effects are still unknown. In this study, the cellular responses of oral cancer cells to AEGT-pBuOH were monitored in terms of cell viability, cell cycle progression, apoptosis, and oxidative stress responses. In an ATP content assay, the cell viability of oral cancer cells treated with AEGT-pBuOH was dose responsively inhibited (p < 0.005). For flow cytometry, AEGT-pBuOH was also found to dose responsively induce cell cycle disturbance by propidium iodide (PI) staining and to induce apoptosis by annexin V/PI and pan-caspase staining (p < 0.005). In AEGT-pBuOH-treated oral cancer cells, the reactive oxygen species (ROS) was increased and mitochondrial membrane potential was decreased in a dose-response manner (p < 0.005). These results suggest that AEGT-pBuOH inhibited the proliferation and induced apoptosis of oral cancer cells involving the ROS generation and mitochondrial depolarization.

Sinuleptolide inhibits proliferation of oral cancer Ca9-22 cells involving apoptosis, oxidative stress, and DNA damage.

OBJECTIVE: Sinuleptolide, a soft corals-derived bioactive norditerpenoid, is a marine natural product with a potent anti-inflammatory effect. We evaluate the potential anti-oral cancer effects of sinuleptolide and investigate the possible mechanisms involved. DESIGNS: Cell viability, cell cycle, apoptosis, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and DNA damage analyses were performed. RESULTS: In a cell viability assay, we found that sinuleptolide is dose-responsively antiproliferative against oral gingival cancer Ca9-22 cells but less harmful to normal human gingival fibroblast (HGF-1) cells (P<0.001). In cell cycle analysis, sinuleptolide induced subG1 accumulation at a higher dose and led to G2/M arrest of Ca9-22 cells (P<0.005). Apoptosis was significantly increased in sinuleptolide-treated Ca9-22 cells based on annexin V and poly(ADP-ribose) polymerase (PARP) expressions (P<0.05-0.0001). Based on flow cytometer analysis, sinuleptolide also induced the generation of ROS and decreased MMP in a dose-responsive manner (P<0.05-0.0001). DNA damage increased dose-responsively after sinuleptolide treatments (P < 0.001) based on comet and γH2AX assays. CONCLUSION: Sinuleptolide can induce an antiproliferation of oral cancer Ca9-22 cells involving apoptosis, oxidative stress and DNA damage, suggesting that sinuleptolide represents a potential chemotherapeutic drug for oral cancer treatment.

Anticancer drugs for the modulation of endoplasmic reticulum stress and oxidative stress.

Prior research has demonstrated how the endoplasmic reticulum (ER) functions as a multifunctional organelle and as a well-orchestrated protein-folding unit. It consists of sensors which detect stress-induced unfolded/misfolded proteins and it is the place where protein folding is catalyzed with chaperones. During this folding process, an immaculate disulfide bond formation requires an oxidized environment provided by the ER. Protein folding and the generation of reactive oxygen species (ROS) as a protein oxidative byproduct in ER are crosslinked. An ER stress-induced response also mediates the expression of the apoptosis-associated gene C/EBP-homologous protein (CHOP) and death receptor 5 (DR5). ER stress induces the upregulation of tumor necrosis factor-related apoptosis inducing ligand (TRAIL) receptor and opening new horizons for therapeutic research. These findings can be used to maximize TRAIL-induced apoptosis in xenografted mice. This review summarizes the current understanding of the interplay between ER stress and ROS. We also discuss how damage-associated molecular patterns (DAMPs) function as modulators of immunogenic cell death and how natural products and drugs have shown potential in regulating ER stress and ROS in different cancer cell lines. Drugs as inducers and inhibitors of ROS modulation may respectively exert inducible and inhibitory effects on ER stress and unfolded protein response (UPR). Reconceptualization of the molecular crosstalk among ROS modulating effectors, ER stress, and DAMPs will lead to advances in anticancer therapy.

Activation and Inhibition of ATM by Phytochemicals: Awakening and Sleeping the Guardian Angel Naturally.

Double-stranded breaks (DSBs) are cytotoxic DNA lesions caused by oxygen radicals, ionizing radiation, and radiomimetic chemicals. Increasing understanding of DNA damage signaling has provided an ever-expanding list of modulators reported to orchestrate DNA damage repair and ataxia telangiectasia mutated (ATM) is the master regulator and main transducer of the DSB response. Increasingly, it is being realized that DNA damage response is a synchronized and branched network that functionalizes different molecular cascades to activate special checkpoints, thus temporarily arresting progression of the cell cycle while damage is being assessed and processed. It is noteworthy that both nutrigenetics and nutrigenomics have revolutionized the field of molecular biology and rapidly accumulating experimental evidence has started to shed light on biological activities of a wide range of phytochemicals reported to modulate cell cycle, DNA repair, cell growth, differentiation and apoptosis as evidenced by cell-based studies. In this review, we have attempted to provide an overview of DNA damage signaling, how ATM signaling regulates tumor necrosis factors-related apoptosis inducing ligand (TRAIL)-induced intracellular network. We also illuminate on how resveratrol, epigallocatechin gallate, curcumin, jaceosidin, cucurbitacin, apigenin, genistein, and others trigger activation of ATM in different cancer cells as well as agents for ATM inactivation. Understanding the interplay of TRAIL-induced intracellular signaling and ATM modulation of downstream effectors is very important. This holds particularly for a reconceptualization of the apparently paradoxical roles and therapeutically targetable for enhancing the response to DNA damage-inducing therapy.

Concentration effects of grape seed extracts in anti-oral cancer cells involving differential apoptosis, oxidative stress, and DNA damage.

BACKGROUND: Grape seeds extract (GSE) is a famous health food supplement for its antioxidant property. Different concentrations of GSE may have different impacts on cellular oxidative/reduction homeostasis. Antiproliferative effect of GSE has been reported in many cancers but rarely in oral cancer. METHODS: The aim of this study is to examine the antioral cancer effects of different concentrations of GSE in terms of cell viability, apoptosis, reactive oxygen species (ROS), mitochondrial function, and DNA damage. RESULTS: High concentrations (50-400 µg/ml) of GSE dose-responsively inhibited proliferation of oral cancer Ca9-22 cells but low concentrations (1-10 µg/ml) of GSE showed a mild effect in a MTS assay. For apoptosis analyses, subG1 population and annexin V intensity in high concentrations of GSE-treated Ca9-22 cells was increased but less so at low concentrations. ROS generation and mitochondrial depolarization increased dose-responsively at high concentrations but showed minor changes at low concentrations of GSE in Ca9-22 cells. Additionally, high concentrations of GSE dose-responsively induced more γH2AX-based DNA damage than low concentrations. CONCLUSIONS: Differential concentrations of GSE may have a differentially antiproliferative function against oral cancer cells via differential apoptosis, oxidative stress and DNA damage.

Methanolic extracts of Solieria robusta inhibits proliferation of oral cancer Ca9-22 cells via apoptosis and oxidative stress.

Many red algae-derived natural products are known to have anticancer effects. The biological functions of the red alga Solieria robusta from the Karachi coast (Pakistan) remain unclear. Here, we prepared a methanolic extracts of S. robusta (MESR) to examine its possible anti-oral cancer effects and the corresponding mechanism of action. Cell viability of MESR-incubated oral cancer Ca9-22 cells was dose-responsively decreased (p<0.001). According to a propidium iodide (PI)-based assay the cell cycle distribution was dramatically changed, especially for subG1 accumulation. Annexin V/PI assay of apoptosis using flow cytometry also showed that MESR-incubated Ca9-22 cells were dose-responsively increased (p<0.001). For evaluation of oxidative stress in MESR-incubated Ca9-22 cells, we found that reactive oxygen species (ROS) were overexpressed dose- and time-responsively and mitochondrial depolarization was also increased (p<0.001). Taken together, MESR showed inhibitory effects on oral cancer proliferation coupled with apoptosis and oxidative stress.

Reactive oxygen species and autophagy modulation in non-marine drugs and marine drugs.

It is becoming more understandable that an existing challenge for translational research is the development of pharmaceuticals that appropriately target reactive oxygen species (ROS)-mediated molecular networks in cancer cells. In line with this approach, there is an overwhelmingly increasing list of many non-marine drugs and marine drugs reported to be involved in inhibiting and suppressing cancer progression through ROS-mediated cell death. In this review, we describe the strategy of oxidative stress-based therapy and connect the ROS modulating effect to the regulation of apoptosis and autophagy. Finally, we focus on exploring the function and mechanism of cancer therapy by the autophagy modulators including inhibitors and inducers from non-marine drugs and marine drugs.