Manoalide Preferentially Provides Antiproliferation of Oral Cancer Cells by Oxidative Stress-Mediated Apoptosis and DNA Damage

Marine anticancer drugs in modulating miRNAs and antioxidant signaling

Several marine drugs exert anticancer effects by inducing oxidative stress, which becomes overloaded and kills cancer cells when redox homeostasis is imbalanced. The downregulation of antioxidant signaling induces oxidative stress, while its upregulation attenuates oxidative stress. Marine drugs have miRNA-modulating effects against cancer cells. However, the potential antioxidant targets of such drugs have been rarely explored. This review aims to categorize the marine-drug-modulated miRNAs that downregulate their antioxidant targets, causing oxidative stress in anticancer treatments. We also categorize the downregulation of oxidative-stress-inducing miRNAs in antioxidant protection among non-cancer cells. We summarize the putative antioxidant targets of miRNA-modulating marine drugs by introducing a bioinformatics tool (miRDB). Finally, the marine drugs affecting antioxidant targets are surveyed. In this way, the connections between marine drugs and their modulating miRNA and antioxidant targets are innovatively categorized to provide a precise network for exploring their potential anticancer functions and protective effects on non-cancer cells.

Demethoxymurrapanine, an indole-naphthoquinone alkaloid, inhibits the proliferation of oral cancer cells without major side effects on normal cells

Antioral cancer drugs need a greater antiproliferative impact on cancer than on normal cells. Demethoxymurrapanine (DEMU) inhibits proliferation in several cancer cells, but an in-depth investigation was necessary. This study evaluated the proliferation-modulating effects of DEMU, focusing on oral cancer and normal cells. DEMU (0, 2, 3, and 4 μg/mL) at 48 h treatments inhibited the proliferation of oral cancer cells (the cell viability (%) for Ca9-22 cells was 100.0 ± 2.2, 75.4 ± 5.6, 26.0 ± 3.8, and 15.4 ± 1.4, and for CAL 27 cells was 100.0 ± 9.4, 77.2 ± 5.9, 57.4 ± 10.7, and 27.1 ± 1.1) more strongly than that of normal cells (the cell viability (%) for S-G cells was 100.0 ± 6.6, 91.0 ± 4.6, 95.0 ± 2.6, and 95.8 ± 5.5), although this was blocked by the antioxidant N-acetylcysteine. The presence of oxidative stress was evidenced by the increase of reactive oxygen species and mitochondrial superoxide and the downregulation of the cellular antioxidant glutathione in oral cancer cells, but these changes were minor in normal cells. DEMU also caused greater induction of the subG1 phase, extrinsic and intrinsic apoptosis (annexin V and caspases 3, 8, and 9), and DNA damage (γH2AX and 8-hydroxy-2-deoxyguanosine) in oral cancer than in normal cells. N-acetylcysteine attenuated all these DEMU-induced changes. Together, these data demonstrate the preferential antiproliferative function of DEMU in oral cancer cells, with the preferential induction of oxidative stress, apoptosis, and DNA damage in these cancer cells, and low cytotoxicity toward normal cells.

6-n-Butoxy-10-nitro-12,13-dioxa-11-azatricyclo[7.3.1.02,7]trideca-2,4,6,10-tetraene Improves the X-ray Sensitivity on Inhibiting Proliferation and Promoting Oxidative Stress and Apoptosis of Oral Cancer Cells

This in vitro study examines the anti-oral cancer effects and mechanisms of a combined X-ray/SK2 treatment, i.e., X-ray and 6-n-butoxy-10-nitro-12,13-dioxa-11-azatricyclo[7.3.1.02,7]trideca-2,4,6,10-tetraene (SK2). ATP cell viability and flow cytometry-based cell cycle, apoptosis, oxidative stress, and DNA damage assessments were conducted. The X-ray/SK2 treatment exhibited lower viability in oral cancer (Ca9-22 and CAL 27) cells than in normal (Smulow-Glickman, S-G) cells, i.e., 32.0%, 46.1% vs. 59.0%, which showed more antiproliferative changes than with X-ray or SK2 treatment. Oral cancer cells under X-ray/SK2 treatment showed slight subG1 and G2/M increments and induced high annexin V-monitored apoptosis compared to X-ray or SK2 treatment. The X-ray/SK2 treatment showed higher caspase 3 and 8 levels for oral cancer cells than other treatments. X-ray/SK2 showed a higher caspase 9 level in CAL 27 cells than other treatments, while Ca9-22 cells showed similar levels under X-ray and/or SK2. The X-ray/SK2 treatment showed higher reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) depletion than other treatments. Meanwhile, the mitochondrial superoxide (MitoSOX) and glutathione levels in X-ray/SK2 treatment did not exhibit the highest rank compared to others. Moreover, oral cancer cells had higher γH2AX and/or 8-hydroxy-2-deoxyguanosine levels from X-ray/SK2 treatment than others. All these measurements for X-ray/SK2 in oral cancer cells were higher than in normal cells and attenuated by N-acetylcysteine. In conclusion, X-ray/SK2 treatment showed ROS-dependent enhanced antiproliferative, apoptotic, and DNA damage effects in oral cancer cells with a lower cytotoxic influence on normal cells.

Exploring the multifaceted effects of Ammi visnaga: subchronic toxicity, antioxidant capacity, immunomodulatory, and anti-inflammatory activities

Ammi visnaga (A. visnaga) is an annual herb that has been used in traditional medicine to treat various ailments attributed to the presence of its bioactive compounds. The purpose of this study was to identify and examine the phytochemical properties of the hydroalcoholic extract of A. visnaga using in vitro and in vivo models. Our findings demonstrated that the extract contained a variety of beneficial components, including phenols, flavonoids, tannins, coumarins, saponins, khellin, and visnagin. The total polyphenolic content and total flavonoid content were 23.26 mg/GAE/g dry weight and 13.26 mg/GAE/g dry weight, respectively. In vitro tests demonstrated that the extract possessed antioxidant properties as evidenced by the ability to scavenge free radicals, including DPPH, ABTS, nitric oxide (NO), phosphomolybdate, and ferric-reducing antioxidant power (FRAP). Further, the extract was found to inhibit hydrogen peroxide (H2O2)-induced hemolysis. In a 90-d in vivo study, female Wistar rats were administered 1 g/kg of A. visnaga extract orally resulting in a significant increase in total white blood cell count. Although morphological changes were observed in the liver, no marked alterations were noted in kidneys and spleen. In a female Swiss albino mice model of acetic acid-induced vascular permeability, A. visnaga significantly inhibited extravasations of Evans blue at doses of 0.5 or 1 g/kg with inhibition percentages of 51 and 65%, respectively, blocking tissue necrosis. The extract also demonstrated potential immunomodulatory properties in mice by enhancing antibody production in response to antigens. In silico molecular docking studies demonstrated a strong affinity between khellin or visnagin and immunomodulatory proteins, NF-κB, p52, and TNF-α. These findings suggest that A. visnaga may be considered a beneficial antioxidant with immunomodulatory properties and might serve as a therapeutic agent to combat certain diseases.

Ameliorative inhibition of sirtuin 6 by imidazole derivative triggers oxidative stress-mediated apoptosis associated with Nrf2/Keap1 signaling in non-small cell lung cancer cell lines

Background: Redox homeostasis is the vital regulatory system with respect to antioxidative response and detoxification. The imbalance of redox homeostasis causes oxidative stress. Nuclear factor-erythroid 2 p45-related factor 2 (Nrf2, also called Nfe2l2)/Kelchlike ECH-associated protein 1 (Keap1) signaling is the major regulator of redox homeostasis. Nrf2/Keap1 signaling is reported to be involved in cancer cell growth and survival. A high level of Nrf2 in cancers is associated with poor prognosis, resistance to therapeutics, and rapid proliferation, framing Nrf2 as an interesting target in cancer biology. Sirtuins (SIRT1-7) are class III histone deacetylases with NAD + dependent deacetylase activity that have a remarkable impact on antioxidant and redox signaling (ARS) linked with Nrf2 deacetylation thereby increasing its transcription by epigenetic modifications which has been identified as a crucial event in cancer progression under the influence of oxidative stress in various transformed cells. SIRT6 plays an important role in the cytoprotective effect of multiple diseases, including cancer. This study aimed to inhibit SIRT6 using an imidazole derivative, Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate, to assess its impact on Nrf2/Keap1 signaling in A549 and NCI-H460 cell lines. Method: Half maximal inhibitory concentration (IC50) of Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate was fixed by cell viability assay. The changes in the gene expression of important regulators involved in this study were examined using quantitative real-time PCR (qRT-PCR) and protein expression changes were confirmed by Western blotting. The changes in the antioxidant molecules are determined by biochemical assays. Further, morphological studies were performed to observe the generation of reactive oxygen species, mitochondrial damage, and apoptosis. Results: We inhibited SIRT6 using Ethyl 2-[5-(4-chlorophenyl)-2-methyl-1-H-Imidazole-4-yl] acetate and demonstrated that SIRT6 inhibition impacts the modulation of antioxidant and redox signaling. The level of antioxidant enzymes and percentage of reactive oxygen species scavenging activity were depleted. The morphological studies showed ROS generation, mitochondrial damage, nuclear damage, and apoptosis. The molecular examination of apoptotic factors confirmed apoptotic cell death. Further, molecular studies confirmed the changes in Nrf2 and Keap1 expression during SIRT6 inhibition. Conclusion: The overall study suggests that SIRT6 inhibition by imidazole derivative disrupts Nrf2/Keap1 signaling leading to oxidative stress and apoptosis induction.

The neddylation inhibitor MLN4924 inhibits proliferation and triggers apoptosis of oral cancer cells but not for normal cells

Increased neddylation benefits the survival of several types of cancer cells. The inhibition of neddylation has the potential to exert anticancer effects but is rarely assessed in oral cancer cells. This study aimed to investigate the antiproliferation potential of a neddylation inhibitor MLN4924 (pevonedistat) for oral cancer cells. MLN4924 inhibited the cell viability of oral cancer cells more than that of normal oral cells (HGF-1) with 100% viability, that is, IC50 values of oral cancer cells (CAL 27, OC-2, and Ca9-22) are 1.8, 1.4, and 1.9 μM. MLN4924 caused apoptotic changes such as the subG1 accumulation, activation of annexin V, pancaspase, and caspases 3/8/9 of oral cancer cells at a greater rate than in normal oral cells. MLN4924 induced greater oxidative stress in oral cancer cells compared to normal cells by upregulating reactive oxygen species and mitochondrial superoxide and depleting the mitochondrial membrane potential and glutathione. In oral cancer cells, preferential inductions also occurred for DNA damage (γH2AX and 8-oxo-2'-deoxyguanosine). Therefore, this investigation demonstrates that MLN4924 is a potential anti-oral-cancer agent showing preferential inhibition of apoptosis and promotion of DNA damage with fewer cytotoxic effects on normal cells.

Manoalide Induces Intrinsic Apoptosis by Oxidative Stress and Mitochondrial Dysfunction in Human Osteosarcoma Cells

Osteosarcoma (OS) is the most common primary malignant bone tumor that produces immature osteoid. Metastatic OS has a poor prognosis with a death rate of >70%. Manoalide is a natural sesterterpenoid isolated from marine sponges. It is a phospholipase A2 inhibitor with anti-inflammatory, analgesic, and anti-cancer properties. This study aimed to investigate the mechanism and effect of manoalide on OS cells. Our experiments showed that manoalide induced cytotoxicity in 143B and MG63 cells (human osteosarcoma). Treatment with manoalide at concentrations of 10, 20, and 40 µM for 24 and 48 h reduced MG63 cell viability to 45.13-4.40% (p < 0.01). Meanwhile, manoalide caused reactive oxygen species (ROS) overproduction and disrupted antioxidant proteins, activating the apoptotic proteins caspase-9/-3 and PARP (Poly (ADP-ribose) polymerase). Excessive levels of ROS in the mitochondria affected oxidative phosphorylation, ATP generation, and membrane potential (ΔΨ_m). Additionally, manoalide down-regulated mitochondrial fusion protein and up-regulated mitochondrial fission protein, resulting in mitochondrial fragmentation and impaired function. On the contrary, a pre-treatment with n-acetyl-l-cysteine ameliorated manoalide-induced apoptosis, ROS, and antioxidant proteins in OS cells. Overall, our findings show that manoalide induces oxidative stress, mitochondrial dysfunction, and apoptosis, causing the cell death of OS cells, showing potential as an innovative alternative treatment in human OS.

Synthesis and Anticancer Evaluation of 4-Anilinoquinolinylchalcone Derivatives

A series of 4-anilinoquinolinylchalcone derivatives were synthesized and evaluated for antiproliferative activities against the growth of human cancer cell lines (Huh-7 and MDA-MB-231) and normal lung cells (MRC-5). The results exhibited low cytotoxicity against human lung cells (MRC-5). Among them, (E)-3-{4-{[4-(benzyloxy)phenyl]amino}quinolin-2-yl}-1-(4-methoxyphenyl) prop-2-en-1-one (4a) was found to have the highest cytotoxicity in breast cancer cells and low cytotoxicity in normal cells. Compound 4a causes ATP depletion and apoptosis of breast cancer MDA-MB-231 cells and triggers reactive oxygen species (ROS)-dependent caspase 3/7 activation. In conclusion, it is worth studying 4-anilinoquinolinylchalcone derivatives further as new potential anticancer agents for the treatment of human cancers.

NLRP3 Inflammasome’s Activation in Acute and Chronic Brain Diseases—An Update on Pathogenetic Mechanisms and Therapeutic Perspectives with Respect to Other Inflammasomes

Increasingly prevalent acute and chronic human brain diseases are scourges for the elderly. Besides the lack of therapies, these ailments share a neuroinflammation that is triggered/sustained by different innate immunity-related protein oligomers called inflammasomes. Relevant neuroinflammation players such as microglia/monocytes typically exhibit a strong NLRP3 inflammasome activation. Hence the idea that NLRP3 suppression might solve neurodegenerative ailments. Here we review the recent Literature about this topic. First, we update conditions and mechanisms, including RNAs, extracellular vesicles/exosomes, endogenous compounds, and ethnic/pharmacological agents/extracts regulating NLRP3 function. Second, we pinpoint NLRP3-activating mechanisms and known NLRP3 inhibition effects in acute (ischemia, stroke, hemorrhage), chronic (Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, MS, ALS), and virus-induced (Zika, SARS-CoV-2, and others) human brain diseases. The available data show that (i) disease-specific divergent mechanisms activate the (mainly animal) brains NLRP3; (ii) no evidence proves that NLRP3 inhibition modifies human brain diseases (yet ad hoc trials are ongoing); and (iii) no findings exclude that concurrently activated other-than-NLRP3 inflammasomes might functionally replace the inhibited NLRP3. Finally, we highlight that among the causes of the persistent lack of therapies are the species difference problem in disease models and a preference for symptomatic over etiologic therapeutic approaches. Therefore, we posit that human neural cell-based disease models could drive etiological, pathogenetic, and therapeutic advances, including NLRP3’s and other inflammasomes’ regulation, while minimizing failure risks in candidate drug trials.

Oxidative-Stress-Mediated ER Stress Is Involved in Regulating Manoalide-Induced Antiproliferation in Oral Cancer Cells

Manoalide provides preferential antiproliferation of oral cancer but is non-cytotoxic to normal cells by modulating reactive oxygen species (ROS) and apoptosis. Although ROS interplays with endoplasmic reticulum (ER) stress and apoptosis, the influence of ER stress on manoalide-triggered apoptosis has not been reported. The role of ER stress in manoalide-induced preferential antiproliferation and apoptosis was assessed in this study. Manoalide induces a higher ER expansion and aggresome accumulation of oral cancer than normal cells. Generally, manoalide differentially influences higher mRNA and protein expressions of ER-stress-associated genes (PERK, IRE1α, ATF6, and BIP) in oral cancer cells than in normal cells. Subsequently, the contribution of ER stress on manoalide-treated oral cancer cells was further examined. ER stress inducer, thapsigargin, enhances the manoalide-induced antiproliferation, caspase 3/7 activation, and autophagy of oral cancer cells rather than normal cells. Moreover, N-acetylcysteine, an ROS inhibitor, reverses the responses of ER stress, aggresome formation, and the antiproliferation of oral cancer cells. Consequently, the preferential ER stress of manoalide-treated oral cancer cells is crucial for its antiproliferative effect.

Natural product manoalide promotes EGFR-TKI sensitivity of lung cancer cells by KRAS-ERK pathway and mitochondrial Ca2+ overload-induced ferroptosis

Background: Manoalide (MA), a proven natural inhibitor of PLA2 has anticancer effects, but its potential application and mechanism as an anticancer drug to promote EGFR-TKI sensitivity in lung cancer cells have not been studied. Methods: KRAS-mutated lung cancer cells and organoids, acquired osimertinib-resistant lung cancer cell lines HCC827OR, were used as EGFR-TKI-resistant models. CCK-8, clone formation, apoptosis assays, and calcein-AM staining were performed to investigate the inhibitory effects of MA in lung cancer cells and organoids. The flow cytometry or confocal microscope was used to detect lipid droplets, ROS, lipid peroxidation, mitochondria Ca²⁺, and iron content. The oxygen consumption rate (OCR) and fatty acid oxidation (FAO) were used to estimate the effect of MA on mitochondrial function. Results: MA inhibits the proliferation of KRAS-mutated lung cancer cells and organoids. In addition, MA induces ER stress in a ROS-dependent mechanism. The ROS induced by MA is mainly in mitochondrial and causes lipid peroxidation, thereby inhibiting mitochondrial FAO metabolism and promoting the accumulation of lipid droplets. MA also suppresses the KRAS-ERK pathway through ROS and promotes the sensitivity of KRAS-mutated lung cancer cells and organoids to osimertinib. Furthermore, MA induces ferroptosis by suppressing the NRF2-SLC7A11 axis and mitochondrial Ca²⁺ overload induced-FTH1 pathways to promote the sensitivity of osimertinib-resistant lung cancer cells to osimertinib. Conclusions: MA is a candidate EGFR-TKI sensitizer in KRAS-mutated and osimertinib-resistant lung cancer cells.

Roles of Mitochondria in Oral Squamous Cell Carcinoma Therapy: Friend or Foe?

Oral squamous cell carcinoma (OSCC) therapy is unsatisfactory, and the prevalence of the disease is increasing. The role of mitochondria in OSCC therapy has recently attracted increasing attention, however, many mechanisms remain unclear. Therefore, we elaborate upon relative studies in this review to achieve a better therapeutic effect of OSCC treatment in the future. Interestingly, we found that mitochondria not only contribute to OSCC therapy but also promote resistance, and targeting the mitochondria of OSCC via nanoparticles is a promising way to treat OSCC.

Antioral Cancer Effects by the Nitrated [6,6,6]Tricycles Compound (SK1) In Vitro

A novel nitrated [6,6,6]tricycles-derived compound containing nitro, methoxy, and ispropyloxy groups, namely SK1, was developed in our previous report. However, the anticancer effects of SK1 were not assessed. Moreover, SK1 contains two nitro groups (NO2) and one nitrogen-oxygen (N-O) bond exhibiting the potential for oxidative stress generation, but this was not examined. The present study aimed to evaluate the antiproliferation effects and oxidative stress and its associated responses between oral cancer and normal cells. Based on the MTS assay, SK1 demonstrated more antiproliferation ability in oral cancer cells than normal cells, reversed by N-acetylcysteine. This suggests that SK1 causes antiproliferation effects preferentially in an oxidative stress-dependent manner. The oxidative stress-associated responses were further validated, showing higher ROS/MitoSOX burst, MMP, and GSH depletion in oral cancer cells than in normal cells. Meanwhile, SK1 caused oxidative stress-causing apoptosis, such as caspases 3/8/9, and DNA damages, such as γH2AX and 8-OHdG, to a greater extent in oral cancer cells than in normal cells. Siilar to cell viability, these oxidative stress responses were partially diminished by NAC, indicating that SK1 promoted oxidative stress-dependent responses. In conclusion, SK1 exerts oxidative stress, apoptosis, and DNA damage to a greater extent to oral cancer cells than in normal cells.

Methanol Extract of Clavularia inflata Exerts Apoptosis and DNA Damage to Oral Cancer Cells

Antiproliferation effects of Clavularia-derived natural products against cancer cells have been reported on, but most studies have focused on identifying bioactive compounds, lacking a detailed investigation of the molecular mechanism. Crude extracts generally exhibit multiple targeting potentials for anticancer effects, but they have rarely been assessed for methanol extracts of Clavularia inflata (MECI). This investigation aims to evaluate the antiproliferation of MECI and to examine several potential mechanisms between oral cancer and normal cells. A 24 h MTS assay demonstrated that MECI decreased cell viability in several oral cancer cell lines more than in normal cells. N-acetylcysteine (NAC), an oxidative stress inhibitor, recovered these antiproliferation effects. Higher oxidative stress was stimulated by MECI in oral cancer cells than in normal cells, as proven by examining reactive oxygen species and mitochondrial superoxide. This preferential induction of oxidative stress was partly explained by downregulating more cellular antioxidants, such as glutathione, in oral cancer cells than in normal cells. Consequently, the MECI-generated high oxidative stress in oral cancer cells was preferred to trigger more subG1 population, apoptosis expression (annexin V and caspase activation), and DNA damage, reverted by NAC. In conclusion, MECI is a potent marine natural product showing preferential antiproliferation against oral cancer cells.

Physapruin A Enhances DNA Damage and Inhibits DNA Repair to Suppress Oral Cancer Cell Proliferation

The selective antiproliferation to oral cancer cells of Physalis peruviana-derived physapruin A (PHA) is rarely reported. Either drug-induced apoptosis and DNA damage or DNA repair suppression may effectively inhibit cancer cell proliferation. This study examined the selective antiproliferation ability of PHA and explored detailed mechanisms of apoptosis, DNA damage, and repair. During an ATP assay, PHA provided high cytotoxicity to two oral cancer cell lines (CAL 27 and Ca9-22) but no cytotoxicity to two non-malignant oral cells (HGF-1 and SG). This selective antiproliferation of PHA was associated with the selective generation of reactive oxygen species (ROS) in oral cancer cells rather than in non-malignant oral cells, as detected by flow cytometry. Moreover, PHA induced other oxidative stresses in oral cancer cells, such as mitochondrial superoxide generation and mitochondrial membrane potential depletion. PHA also demonstrated selective apoptosis in oral cancer cells rather than non-malignant cells in annexin V/7-aminoactinmycin D and caspase 3/7 activity assays. In flow cytometry and immunofluorescence assays, PHA induced γH2AX expressions and increased the γH2AX foci number of DNA damages in oral cancer cells. In contrast, the mRNA expressions for DNA repair signaling, including homologous recombination (HR) and non-homologous end joining (NHEJ)-associated genes, were inhibited by PHA in oral cancer cells. Moreover, the PHA-induced changes were alleviated by the oxidative stress inhibitor N-acetylcysteine. Therefore, PHA generates selective antiproliferation, oxidative stress, and apoptosis associated with DNA damage induction and DNA repair suppression in oral cancer cells.

Physapruin A Induces Reactive Oxygen Species to Trigger Cytoprotective Autophagy of Breast Cancer Cells

Physalis peruviana-derived physapruin A (PHA) is a potent compound that selectively generates reactive oxygen species (ROS) and induces cancer cell death. Autophagy, a cellular self-clearance pathway, can be induced by ROS and plays a dual role in cancer cell death. However, the role of autophagy in PHA-treated cancer cells is not understood. Our study initially showed that autophagy inhibitors such as bafilomycin A1 enhanced the cytotoxic effects of PHA in breast cancer cell lines, including MCF7 and MDA-MB-231. PHA treatment decreased the p62 protein level and increased LC3-II flux. PHA increased the fluorescence intensity of DAPGreen and DALGreen, which are used to reflect the formation of autophagosome/autolysosome and autolysosome, respectively. ROS scavenger N-acetylcysteine (NAC) decreased PHA-elevated autophagy activity, implying that PHA-induced ROS may be required for autophagy induction in breast cancer cells. Moreover, the autophagy inhibitor increased ROS levels and enhanced PHA-elevated ROS levels, while NAC scavenges the produced ROS resulting from PHA and autophagy inhibitor. In addition, the autophagy inhibitor elevated the PHA-induced proportion of annexin V/7-aminoactinmycin D and cleavage of caspase-3/8/9 and poly (ADP-ribose) polymerase. In contrast, NAC and apoptosis inhibitor Z-VAD-FMK blocked the proportion of annexin V/7-aminoactinmycin D and the activation of caspases. Taken together, PHA induced ROS to promote autophagy, which might play an antioxidant and anti-apoptotic role in breast cancer cells.

Brown Algae-Derived Fucoidan Exerts Oxidative Stress-Dependent Antiproliferation on Oral Cancer Cells

Fucoidan is a dietary brown algae-derived fucose-rich polysaccharide. However, the anticancer effects of fucoidan for oral cancer treatment remain unclear, particularly in terms of its preferential antiproliferation ability and oxidative-stress-associated responses. This study first evaluated the effects and mechanisms of the preferential antiproliferation of fucoidan between oral cancer and non-malignant oral cells (S–G). In a 48 h MTS assay, fucoidan showed higher antiproliferation in response to five types of oral cancer cells, but not S–G cells, demonstrating preferential antiproliferation of oral cancer cells. Oral cancer cells (Ca9-22 and CAL 27) showing high sensitivity to fucoidan were selected to explore the antiproliferation mechanism compared to S–G cells. Fucoidan showed subG1 accumulation and an annexin V increase in apoptosis, accompanied by caspase 8, 9, and 3 activations in oral cancer cells, but not in S–G cells. Fucoidan increased reactive oxygen species and mitochondrial superoxide levels and decreased cellular glutathione in oral cancer cells compared with S–G cells. These oxidative stress effects were attributed to the downregulation of antioxidant signaling genes (NRF2, TXN, and HMOX1) in oral cancer cells rather than S–G cells. Fucoidan showed DNA damage-inducible effects (γH2AX and 8-hydroxy-2-deoxyguanosine) in oral cancer cells but not in S–G cells. Accordingly, these preferential changes in oral cancer but not in non-malignant cells contribute to the preferential antiproliferation mechanism of fucoidan. Furthermore, these changes were reverted by pretreatment with the antioxidant N-acetylcysteine. Therefore, for the first time, this study provides a detailed understanding of the preferential antiproliferation effects and mechanisms of fucoidan in oral cancer cells.

Combined Treatment with Cryptocaryone and Ultraviolet C Promotes Antiproliferation and Apoptosis of Oral Cancer Cells

Cryptocaryone (CPC) was previously reported as preferential for killing natural products in oral cancer cells. However, its radiosensitizing potential combined with ultraviolet C (UVC) cell killing of oral cancer cells remains unclear. This study evaluates the combined anti-proliferation effect and clarifies the mechanism of combined UVC/CPC effects on oral cancer cells. UVC/CPC shows higher anti-proliferation than individual and control treatments in a low cytotoxic environment on normal oral cells. Mechanistically, combined UVC/CPC generates high levels of reactive oxygen species and induces mitochondrial dysfunction by generating mitochondrial superoxide, increasing mitochondrial mass and causing the potential destruction of the mitochondrial membrane compared to individual treatments. Moreover, combined UVC/CPC causes higher G2/M arrest and triggers apoptosis, with greater evidence of cell cycle disturbance, annexin V, pancaspase, caspases 3/7 expression or activity in oral cancer cells than individual treatments. Western blotting further indicates that UVC/CPC induces overexpression for cleaved types of poly (ADP-ribose) polymerase and caspase 3 more than individual treatments. Additionally, UVC/CPC highly induces γH2AX and 8-hydroxy-2'-deoxyguanosine adducts as DNA damage in oral cancer cells. Taken together, CPC shows a radiosensitizing anti-proliferation effect on UVC irradiated oral cancer cells with combined effects through oxidative stress, apoptosis and DNA damage.

Inhibition of the NLRP3 Inflammasome Activation by Manoalide Ameliorates Experimental Autoimmune Encephalomyelitis Pathogenesis

The activation of NLRP3 inflammasome leads to cell pyroptosis and inflammatory cytokines secretion and gets involved in the development of many diseases, such as neuroinflammation and metabolic syndrome, but the drugs targeting NLRP3 are not clinically available for now. Through screening the small molecule library, we found that manoalide is a highly selective small molecule inhibitor of NLRP3. Mechanismly, manoalide inhibited the NLRP3 inflammasome activation by acting downstream of potassium efflux, chloride efflux and mitochondrial dysfunction. Moreover, manoalide blocked the interaction between NEK7 and NLRP3 by covalently binding to Lys 377 of the NLRP3 protein. Treatment of manoalide relieved the pathogenesis of experimental autoimmune encephalomyelitis (EAE) in mice. Thus, our results identify manoalide as a selective and covalent NLRP3 inhibitor and suggest it has the potential for the treatment of NLRP3-associated diseases.

Carnosic Acid Suppresses the Development of Oral Squamous Cell Carcinoma via Mitochondrial-Mediated Apoptosis

Oral squamous cell carcinoma (OSCC) predominantly consists of squamous cells and is the tumor with the highest incidence of the head and neck. Carnosic acid (CA), a natural monomer drug obtained from rosemary and salvia, shows various pharmacological effects, including of tumor development. This study aimed to assess for an effect of CA on the development of OSCC and the underlying mechanisms. In CAL27 and SCC9 cells, CA inhibited cell proliferation and migration, increased intracellular levels of reactive oxygen species (ROS) and Ca²⁺, decreased the mitochondrial membrane potential (MMP), and promoted apoptosis. In CAL27- and SCC9-xenotransplanted BALB/c nude mice, CA inhibited the tumor growth without affecting the body weight and tissue morphology. CA upregulated Bax, Bad, cleaved Caspase-3 and -9 levels, and the cleaved PARP1/PARP1 ratio but downregulated Bcl-2 in CA-treated OSCC cells and OSCC cells-xenotransplanted BALB/c nude mice. These results indicate that CA suppresses OSCC at least via the mitochondrial apoptotic pathway and offers this natural compound as a potential therapeutic against OSCC.

A calcium channel blocker, manoalide exerts an anti-allergic inflammatory effect through attenuating NF-κB activity

BACKGROUND

Many people are troubled by allergic inflammation including ocular allergic diseases, anaphylaxis, allergic rhinitis, atopic dermatitis, and eczema. Consequently, finding medications for use in allergic inflammation therapy is crucial in human health. Manoalide, a marine natural product isolated as an anti-bacterial metabolite from Luffariella variabilis, is a calcium channel blocker. However, its latent ability as an anti-allergic inflammatory agent has not yet been reported. Our research aimed to elucidate whether manoalide exerts an anti-allergic inflammatory effect in the human mast cell line, HMC-1.

METHODS

Herein, we investigated the immunoregulatory effects and molecular mechanisms of manoalide in HMC-1 cells.

RESULTS

Manoalide significantly alleviated secretion of the inflammatory cytokines interleukin (IL)-1β, thymic stromal lymphopoietin, tumor necrosis factor-α, IL-6, and IL-8 via blockage of caspase-1 without cytotoxicity in activated HMC-1 cells. Activation of nuclear factor-κB increased by mast cell stimulation was attenuated by treatment with manoalide. In addition, we demonstrated that manoalide treatment remarkably attenuated the activation of mitogen-activated protein kinases in activated-HMC-1 cells.

CONCLUSIONS

Taken together, our findings indicate manoalide has an anti-allergic inflammatory role, and we propose that manoalide might have potential as a novel anti-allergic inflammatory agent.

Burmannic Acid Inhibits Proliferation and Induces Oxidative Stress Response of Oral Cancer Cells

Burmannic acid (BURA) is a new apocarotenoid bioactive compound derived from Indonesian cinnamon; however, its anticancer effect has rarely been investigated in oral cancer cells. In this investigation, the consequences of the antiproliferation of oral cancer cells effected by BURA were evaluated. BURA selectively suppressed cell proliferation of oral cancer cells (Ca9-22 and CAL 27) but showed little cytotoxicity to normal oral cells (HGF-1). In terms of mechanism, BURA perturbed cell cycle distribution, upregulated mitochondrial superoxide, induced mitochondrial depolarization, triggered γH2AX and 8-hydroxy-2-deoxyguanosine DNA damage, and induced apoptosis and caspase 3/8/9 activation in oral cancer cells. Application of N-acetylcysteine confirmed oxidative stress as the critical factor in promoting antiproliferation, apoptosis, and DNA damage in oral cancer cells.

Nepenthes Extract Induces Selective Killing, Necrosis, and Apoptosis in Oral Cancer Cells

Ethyl acetate Nepenthes extract (EANT) from Nepenthes thorellii × (ventricosa × maxima) shows antiproliferation and apoptosis but not necrosis in breast cancer cells, but this has not been investigated in oral cancer cells. In the present study, EANT shows no cytotoxicity to normal oral cells but exhibits selective killing to six oral cancer cell lines. They were suppressed by pretreatment of the antioxidant inhibitor N-acetylcysteine (NAC), demonstrating that EANT-induced cell death was mediated by oxidative stress. Concerning high sensitivity to EANT, Ca9-22 and CAL 27 oral cancer cells were chosen for exploring detailed selective killing mechanisms. EANT triggers a mixture of necrosis and apoptosis as determined by annexin V/7-aminoactinmycin D analysis. Still, they show differential switches from necrosis at a low (10 μg/mL) concentration to apoptosis at high (25 μg/mL) concentration of EANT in oral cancer cells. NAC induces necrosis but suppresses annexin V-detected apoptosis in oral cancer cells. Necrostatin 1 (NEC1), a necroptosis inhibitor, moderately suppresses necrosis but induces apoptosis at 10 μg/mL EANT. In contrast, Z-VAD-FMK, a pancaspase inhibitor, slightly causes necrosis but suppresses apoptosis at 10 μg/mL EANT. Furthermore, the flow cytometry-detected pancaspase activity is dose-responsively increased but is suppressed by NAC and ZVAD, although not for NEC1 in oral cancer cells. EANT causes several oxidative stress events such as reactive oxygen species, mitochondrial superoxide, and mitochondrial membrane depolarization. In response to oxidative stresses, the mRNA for antioxidant signaling, such as nuclear factor erythroid 2-like 2 (NFE2L2), catalase (CAT), heme oxygenase 1 (HMOX1), and thioredoxin (TXN), are overexpressed in oral cancer cells. Moreover, EANT also triggers DNA damage, as detected by γH2AX and 8-oxo-2'-deoxyguanosine adducts. The dependence of oxidative stress is validated by the evidence that NAC pretreatment reverts the changes of cellular and mitochondrial stress and DNA damage. Therefore, EANT exhibits antiproliferation involving an oxidative stress-dependent necrosis/apoptosis switch and DNA damage in oral cancer cells.

Pomegranate Extract (POMx) Induces Mitochondrial Dysfunction and Apoptosis of Oral Cancer Cells

The anticancer effect of pomegranate polyphenolic extract POMx in oral cancer cells has rarely been explored, especially where its impact on mitochondrial functioning is concerned. Here, we attempt to evaluate the proliferation modulating function and mechanism of POMx against human oral cancer (Ca9-22, HSC-3, and OC-2) cells. POMx induced ATP depletion, subG1 accumulation, and annexin V/Western blotting-detected apoptosis in these three oral cancer cell lines but showed no toxicity to normal oral cell lines (HGF-1). POMx triggered mitochondrial membrane potential (MitoMP) disruption and mitochondrial superoxide (MitoSOX) generation associated with the differential downregulation of several antioxidant gene mRNA/protein expressions in oral cancer cells. POMx downregulated mitochondrial mass, mitochondrial DNA copy number, and mitochondrial biogenesis gene mRNA/protein expression in oral cancer cells. Moreover, POMx induced both PCR-based mitochondrial DNA damage and γH2AX-detected nuclear DNA damage in oral cancer cells. In conclusion, POMx provides antiproliferation and apoptosis of oral cancer cells through mechanisms of mitochondrial impairment.

Realizing the Potential of Blueberry as Natural Inhibitor of Metastasis and Powerful Apoptosis Inducer: Tapping the Treasure Trove for Effective Regulation of Cell Signaling Pathways

Blueberries belong to the genus Vaccinium of the family Ericaceae. Rapidly accumulating experimentally verified data is uncovering the tremendous pharmacological properties of biologically active constituents of blueberries against different diseases. Our rapidly evolving knowledge about the multifaceted nature of cancer has opened new horizons to search for different strategies to target multiple effectors of oncogenic networks to effectively inhibit cancer onset and progression. Excitingly, whole blueberry powder and various bioactive constituents (pterostilbene, malvidin-3-galactoside) of blueberries have been shown to efficiently inhibit metastasis in animal models. These results are encouraging and future studies must focus on the identification of cell signaling pathways effectively modulated by blueberries in different cancers. It seems exciting to note that researchers are focusing on metastasis inhibitory effects of blueberry; however, to reap full benefits, it is necessary to take a step back and critically re-interpret the mechanisms used by active components of blueberry to inhibit or prevent metastasis. JAK/STAT, TGF/SMAD, Notch, SHH/GLI, and Wnt/ β-Catenin have been shown to be directly involved in the regulation of metastasis. However, because of limited studies, it is difficult to critically assess the true potential of blueberry. Loss of apoptosis, metastasis and deregulation of signaling pathways are branching trajectories of molecular oncology. Accordingly, we have to emphasize on these essential facets to realistically claim blueberry as "Superfood". Different clinical trials have been conducted to gather clinical evidence about the chemopreventive role of blueberry or its bioactive components in cancer patients. But it seems clear that because of the lack of sufficient proof-of-concept studies, we cannot extract significant information about the transition of blueberry into the next phases of clinical trials. Overview of the existing scientific evidence revealed visible knowledge gaps and a better understanding of the targets of blueberry will be helpful in efficient and meaningful translation of laboratory findings to clinically effective therapeutics.

Oxidative Stress-Dependent Synergistic Antiproliferation, Apoptosis, and DNA Damage of Ultraviolet-C and Coral-Derived Sinularin Combined Treatment for Oral Cancer Cells

Combined treatment is increasingly used to improve cancer therapy. Non-ionizing radiation ultraviolet-C (UVC) and sinularin, a coral Sinularia flexibilis-derived cembranolide, were separately reported to provide an antiproliferation function to some kinds of cancer cells. However, an antiproliferation function using the combined treatment of UVC/sinularin has not been investigated as yet. This study aimed to examine the combined antiproliferation function and explore the combination of UVC/sinularin in oral cancer cells compared to normal oral cells. Regarding cell viability, UVC/sinularin displays the synergistic and selective killing of two oral cancer cell lines, but remains non-effective for normal oral cell lines compared to treatments in terms of MTS and ATP assays. In tests using the flow cytometry, luminescence, and Western blotting methods, UVC/sinularin-treated oral cancer cells exhibited higher reactive oxygen species production, mitochondrial superoxide generation, mitochondrial membrane potential destruction, annexin V, pan-caspase, caspase 3/7, and cleaved-poly (ADP-ribose) polymerase expressions than that in normal oral cells. Accordingly, oxidative stress and apoptosis are highly induced in a combined UVC/sinularin treatment. Moreover, UVC/sinularin treatment provides higher G2/M arrest and γH2AX/8-hydroxyl-2'deoxyguanosine-detected DNA damages in oral cancer cells than in the separate treatments. A pretreatment can revert all of these changes of UVC/sinularin treatment with the antioxidant N-acetylcysteine. Taken together, UVC/sinularin acting upon oral cancer cells exhibits a synergistic and selective antiproliferation ability involving oxidative stress-dependent apoptosis and cellular DNA damage with low toxic side effects on normal oral cells.

Physalis peruviana-Derived Physapruin A (PHA) Inhibits Breast Cancer Cell Proliferation and Induces Oxidative-Stress-Mediated Apoptosis and DNA Damage

Breast cancer expresses clinically heterogeneous characteristics and requires multipurpose drug development for curing the different tumor subtypes. Many withanolides have been isolated from Physalis species showing anticancer effects, but the anticancer function of physapruin A (PHA) has rarely been investigated. In this study, the anticancer properties of PHA in breast cancer cells were examined by concentration and time-course experiments. In terms of cellular ATP content, PHA inhibited the proliferation of three kinds of breast cancer cells: MCF7 (estrogen receptor (ER)+, progesterone receptor (PR)+/−, human epidermal growth factor receptor 2 (HER2)−), SKBR3 (ER−/PR−/HER2+), and MDA-MB-231 (triple-negative). Moreover, PHA induced G2/M arrest in MCF7 and MDA-MB-231 cells. In terms of flow cytometry, PHA induced the generation of reactive oxygen species (ROS), the generation of mitochondrial superoxide, mitochondrial membrane potential depletion, and γH2AX-detected DNA damage in breast cancer MCF7 and MDA-MB-231 cells, which were suppressed by the ROS inhibitor N-acetylcysteine (NAC). In terms of flow cytometry and Western blotting, PHA induced apoptotic expression (annexin V, and intrinsic and extrinsic apoptotic signaling), which was suppressed by NAC and an apoptosis inhibitor (Z-VAD-FMK), in breast cancer cells. Therefore, PHA is a potential anti-breast-cancer natural product that modulates the oxidative-stress response, cell-cycle disturbance, apoptosis, and γH2AX-detected DNA damage.

Manoalide Shows Mutual Interaction between Cellular and Mitochondrial Reactive Species with Apoptosis in Oral Cancer Cells

We previously found that marine sponge-derived manoalide induced antiproliferation and apoptosis of oral cancer cells as well as reactive species generations probed by dichloro-dihydrofluorescein diacetate (DCFH-DA) and MitoSOX Red. However, the sources of cellular and mitochondrial redox stresses and the mutual interacting effects between these redox stresses and apoptosis remain unclear. To address this issue, we examined a panel of reactive species and used the inhibitors of cellular reactive species (N-acetylcysteine (NAC)), mitochondrial reactive species (MitoTEMPO), and apoptosis (Z-VAD-FMK; ZVAD) to explore their interactions in manoalide-treated oral cancer Ca9-22 and CAL 27 cells. Hydroxyl (˙OH), nitrogen dioxide (NO₂˙), nitric oxide (˙NO), carbonate radical-anion (CO₃ ^˙-), peroxynitrite (ONOO^-), and superoxide (O₂ ^˙-) were increased in oral cancer cells following manoalide treatments in terms of fluorescence staining and flow cytometry. Cellular reactive species (˙OH, NO₂ ^·, ˙NO, CO₃ ^˙-, and ONOO^-) as well as cellular and mitochondrial reactive species (O₂ ^˙-) were induced in oral cancer cells following manoalide treatment for 6 h. NAC, MitoTEMPO, and ZVAD inhibit manoalide-induced apoptosis in terms of annexin V and pancaspase activity assays. Moreover, NAC inhibits mitochondrial reactive species and MitoTEMPO inhibits cellular reactive species, suggesting that cellular and mitochondrial reactive species can crosstalk to regulate each other. ZVAD shows suppressing effects on the generation of both cellular and mitochondrial reactive species. In conclusion, manoalide induces reciprocally activation between cellular and mitochondrial reactive species and apoptosis in oral cancer cells.

Application of marine natural products in drug research

New diseases are emerging as the environment changes, so drug manufacturers are always on the lookout for new resources to develop effective and safe drugs. In recent years, many bioactive substances have been produced in the marine environment, which represents an alternative resource for new drugs used to combat major diseases such as cancer or inflammation. Many marine-derived medicinal substances are in preclinical or early stage of clinical development, and some marine drugs have been put on the market, such as ET743 (Yondelis®). This review presents the sources, activities, mechanisms of action and syntheses of bioactive substances based on marine natural products in clinical trials and on the market, which is helpful to understand the progress of drug research by application of marine natural products.

Effect of Diphenyleneiodonium Chloride on Intracellular Reactive Oxygen Species Metabolism with Emphasis on NADPH Oxidase and Mitochondria in Two Therapeutically Relevant Human Cell Types

Reactive oxygen species (ROS) have recently been recognized as important signal transducers, particularly regulating proliferation and differentiation of cells. Diphenyleneiodonium (DPI) is known as an inhibitor of the nicotinamide adenine dinucleotide phosphate oxidase (NOX) and is also affecting mitochondrial function. The aim of this study was to investigate the effect of DPI on ROS metabolism and mitochondrial function in human amniotic membrane mesenchymal stromal cells (hAMSCs), human bone marrow mesenchymal stromal cells (hBMSCs), hBMSCs induced into osteoblast-like cells, and osteosarcoma cell line MG-63. Our data suggested a combination of a membrane potential sensitive fluorescent dye, tetramethylrhodamine methyl ester (TMRM), and a ROS-sensitive dye, CM-H2DCFDA, combined with a pretreatment with mitochondria-targeted ROS scavenger MitoTEMPO as a good tool to examine effects of DPI. We observed critical differences in ROS metabolism between hAMSCs, hBMSCs, osteoblast-like cells, and MG-63 cells, which were linked to energy metabolism. In cell types using predominantly glycolysis as the energy source, such as hAMSCs, DPI predominantly interacted with NOX, and it was not toxic for the cells. In hBMSCs, the ROS turnover was influenced by NOX activity rather than by the mitochondria. In cells with aerobic metabolism, such as MG 63, the mitochondria became an additional target for DPI, and these cells were prone to the toxic effects of DPI. In summary, our data suggest that undifferentiated cells rather than differentiated parenchymal cells should be considered as potential targets for DPI.

CYP26A1 Is a Novel Biomarker for Betel Quid-Related Oral and Pharyngeal Cancers

Betel quid (BQ) has been classified as a Group I human carcinogen in light of evidence demonstrating an association with an elevated risk of oral and pharyngeal cancers. To date, the incidence rate of oral and pharynx cancers among Taiwanese men ranks the highest worldwide. However, no study has yet confirmed variants of CYP26A1 was associated with the risks of oral and pharyngeal cancers. A case-control study was conducted (n = 339). CYP26A1 polymorphism was performed using SNP assay. Real-time qRT-PCR and Western blotting were used to determine the levels of CYP26A1 expression. The cancer cell model involved treatment with arecoline. Our findings showed that the downregulation of CYP26A1 mRNA and protein expression are more frequently observed in cancerous tissues than adjacent normal tissues in patients with oral and pharynx cancers (p < 0.01). We found that CYP26A1 was downregulated as the arecoline dose increased. We hypothesized that lower levels of CYP26A1 mRNA expression can be utilized a clinically biomarker causes oral and pharynx cancers. Arecoline appears to modulate CYP26A1 expression through specific pathways. Carriers of CYP26A1 SNP, rs2068888 (G/G)/rs4418728 (G/G) and who have lower levels of CYP26A1 expression are associated with an increased risk of oral and pharyngeal cancers.

Low Dose Combined Treatment with Ultraviolet-C and Withaferin a Enhances Selective Killing of Oral Cancer Cells

Withaferin A (WFA), a Withania somnifera-derived triterpenoid, is an anticancer natural product. The anticancer effect of nonionizing radiation such as ultraviolet-C (UVC) as well as the combined treatment of UVC and WFA is rarely investigated. Low dose UVC and/or WFA treatments (12 J/m² and/or 1 μM) were chosen to evaluate antioral cancer cell line effects by examining cytotoxicity, cell cycle disruption, apoptosis induction, and DNA damage. For two cancer cell lines (Ca9-22 and HSC-3), single treatment (UVC or WFA) showed about 80% viability, while a combined treatment of UVC/WFA showed about 40% viability. In contrast, there was noncytotoxicity to normal oral cell lines (HGF-1). Compared to single treatment and control, low dose UVC/WFA shows high inductions of apoptosis in terms of flow cytometric detections for subG1, annexin V, pancaspase changes as well as Western blotting for detecting cleaved poly (ADP-ribose) polymerase (c-PARP) and caspase 3 (c-Cas 3) and luciferase assay for detecting Cas 3/7 activity. Low dose UVC/WFA also showed high inductions of oxidative stress and DNA damage in terms of flow cytometric detections of reactive oxygen species (ROS), mitochondrial superoxide (MitoSOX) generation, and membrane potential (MitoMP) destruction, γH2AX and 8-oxo-2’deoxyguanosine (8-oxodG) types of DNA damages. For comparison, low dose UVC/WFA show rare inductions of annexin V, Cas 3/7 activity, ROS, MitoSOX, and MitoMP changes to normal oral HGF-1 cells. Therefore, low dose UVC/WFA provides a novel selectively killing mechanism to oral cancer cells, suggesting that WFA is a UVC sensitizer to inhibit the proliferation of oral cancer cells.

Antimycin A shows selective antiproliferation to oral cancer cells by oxidative stress-mediated apoptosis and DNA damage

The antibiotic antimycin A (AMA) is commonly used as an inhibitor for the electron transport chain but its application in anticancer studies is rare. Recently, the repurposing use of AMA in antiproliferation of several cancer cell types has been reported. However, it is rarely investigated in oral cancer cells. The purpose of this study is to investigate the selective antiproliferation ability of AMA treatment on oral cancer cells. Cell viability, flow cytometry, and western blotting were applied to explore its possible anticancer mechanism in terms of both concentration- and exposure time-effects. AMA shows the higher antiproliferation to two oral cancer CAL 27 and Ca9-22 cell lines than normal oral HGF-1 cell lines. Moreover, AMA induces the production of higher reactive oxygen species (ROS) levels and pan-caspase activation in oral cancer CAL 27 and Ca9-22 cells than in normal oral HGF-1 cells, providing the possible mechanism for its selective antiproliferation effect of AMA. In addition to ROS, AMA induces mitochondrial superoxide (MitoSOX) generation and depletes mitochondrial membrane potential (MitoMP). This further supports the AMA-induced oxidative stress changes in oral cancer CAL 27 and Ca9-22 cells. AMA also shows high expressions of annexin V in CAL 27 and Ca9-22 cells and cleaved forms of poly (ADP-ribose) polymerase (PARP), caspase 9, and caspase 3 in CAL 27 cells, supporting the apoptosis-inducing ability of AMA. Furthermore, AMA induces DNA damage (γH2AX and 8-oxo-2'-deoxyguanosine [8-oxodG]) in CAL 27 and Ca9-22 cells. Notably, the AMA-induced selective antiproliferation, oxidative stress, and DNA damage were partly prevented from N-acetylcysteine (NAC) pretreatments. Taken together, AMA selectively kills oral cancer cells in an oxidative stress-dependent mechanism involving apoptosis and DNA damage.

Withanolide C Inhibits Proliferation of Breast Cancer Cells via Oxidative Stress-Mediated Apoptosis and DNA Damage

Some withanolides, particularly the family of steroidal lactones, show anticancer effects, but this is rarely reported for withanolide C (WHC)—especially anti-breast cancer effects. The subject of this study is to evaluate the ability of WHC to regulate the proliferation of breast cancer cells, using both time and concentration in treatment with WHC. In terms of ATP depletion, WHC induced more antiproliferation to three breast cancer cell lines, SKBR3, MCF7, and MDA-MB-231, than to normal breast M10 cell lines. SKBR3 and MCF7 cells showing higher sensitivity to WHC were used to explore the antiproliferation mechanism. Flow cytometric apoptosis analyses showed that subG1 phase and annexin V population were increased in breast cancer cells after WHC treatment. Western blotting showed that cleaved forms of the apoptotic proteins poly (ADP-ribose) polymerase (c-PARP) and cleaved caspase 3 (c-Cas 3) were increased in breast cancer cells. Flow cytometric oxidative stress analyses showed that WHC triggered reactive oxygen species (ROS) and mitochondrial superoxide (MitoSOX) production as well as glutathione depletion. In contrast, normal breast M10 cells showed lower levels of ROS and annexin V expression than breast cancer cells. Flow cytometric DNA damage analyses showed that WHC triggered γH2AX and 8-oxo-2′-deoxyguanosine (8-oxodG) expression in breast cancer cells. Moreover, N-acetylcysteine (NAC) pretreatment reverted oxidative stress-mediated ATP depletion, apoptosis, and DNA damage. Therefore, WHC kills breast cancer cells depending on oxidative stress-associated mechanisms.

Combined Treatment of Sulfonyl Chromen-4-Ones (CHW09) and Ultraviolet-C (UVC) Enhances Proliferation Inhibition, Apoptosis, Oxidative Stress, and DNA Damage against Oral Cancer Cells

The sensitizing effect of chromone-derived compounds on UVC-induced proliferation inhibition has not been comprehensively investigated so far. The subject of this study was to examine the proliferation change of oral cancer cells while using the combined treatment of UVC (254 nm) with our previously developed sulfonyl chromen-4-ones (CHW09), namely UVC/CHW09. Cell viability, apoptosis, oxidative stress, and DNA damage for the individual and combined treatments for UVC and/or CHW09 were examined in oral cancer Ca9-22 cells. In 24 h MTS assay, UVC (30 J/m²; UVC30), or CHW09 (25 and 50 µg/mL; namely, CHW09-25 and CHW09-50) show 54%, 59%, and 45% viability. The combined treatment (UVC30/CHW09-25 and UVC30/CHW09-50) show lower cell viability (45% and 35%). Mechanistically, UVC/CHW09 induced higher apoptosis than individual treatments and untreated control, which were supported by the evidence of flow cytometry for subG1, annexin V/7-aminoactinomycin D, pancaspase and caspases 3/7 activity, and western blotting for cleaved poly(ADP-ribose) polymerase. Moreover, this cleaved PARP expression was downregulated by pancaspase inhibitor Z-VAD-FMK. UVC/CHW09 showed higher oxidative stress than individual treatments and untreated control in terms of flow cytometry for reactive oxygen species, mitochondrial membrane potential, and mitochondrial mass. Furthermore, UVC/CHW09 showed higher DNA damage than individual treatments and untreated control in terms of flow cytometry for H2A histone family member X and 8-oxo-2’-deoxyguanosine. In conclusion, combined treatment UVC/CHW09 suppresses proliferation, and promotes apoptosis, oxidative stress, and DNA damage against oral cancer cells, providing a novel application of sulfonyl chromen-4-ones in order to sensitize UVC induced proliferation inhibition for oral cancer therapy.

Role of Natural Bioactive Compounds in the Rise and Fall of Cancers

Recent years have seen the idea of a close association between nutrition and the modulation of cancer development/progression reinforced [...].