Bioactive compounds from crocodile (Crocodylus siamensis) white blood cells induced apoptotic cell death in hela cells

Cell-Free Therapies: The Use of Cell Extracts to Mitigate Irradiation-Injured Salivary Glands

Radiotherapy is a standard treatment for head and neck cancer patients worldwide. However, millions of patients who received radiotherapy consequently suffer from xerostomia because of irreversible damage to salivary glands (SGs) caused by irradiation (IR). Current treatments for IR-induced SG hypofunction only provide temporary symptom alleviation but do not repair the damaged SG, thus resulting in limited treatment efficacy. Therefore, there has recently been a growing interest in regenerative treatments, such as cell-free therapies. This review aims to summarize cell-free therapies for IR-induced SG, with a particular emphasis on utilizing diverse cell extract (CE) administrations. Cell extract is a group of heterogeneous mixtures containing multifunctional inter-cellular molecules. This review discusses the current knowledge of CE's components and efficacy. We propose optimal approaches to improve cell extract treatment from multiple perspectives (e.g., delivery routes, preparation methods, and other details regarding CE administration). In addition, the advantages and limitations of CE treatment are systematically discussed by comparing it to other cell-free (such as conditioned media and exosomes) and cell-based therapies. Although a comprehensive identification of the bioactive factors within CEs and their mechanisms of action have yet to be fully understood, we propose cell extract therapy as an effective, practical, user-friendly, and safe option to conventional therapies in IR-induced SG.

PW06 Triggered Fas-FADD to Induce Apoptotic Cell Death In Human Pancreatic Carcinoma MIA PaCa-2 Cells through the Activation of the Caspase-Mediated Pathway

Pancreatic cancer has higher incidence and mortality rates worldwide. PW06 [(E)-3-(9-ethyl-9H-carbazol-3-yl)-1-(2,5-dimethoxyphenyl) prop-2-en-1-one] is a carbazole derivative containing chalcone moiety which was designed for inhibiting tumorigenesis in human pancreatic cancer. This study is aimed at investigating PW06-induced anticancer effects in human pancreatic cancer MIA PaCa-2 cells in vitro. The results showed PW06 potent antiproliferative/cytotoxic activities and induced cell morphological changes in a human pancreatic cancer cell line (MIA PaCa-2), and these effects are concentration-dependent (IC₅₀ is 0.43 μM). Annexin V and DAPI staining assays indicated that PW06 induced apoptotic cell death and DNA condensation. Western blotting indicated that PW06 increased the proapoptotic proteins such as Bak and Bad but decreased the antiapoptotic protein such as Bcl-2 and Bcl-xL. Moreover, PW06 increased the active form of caspase-8, caspase-9, and caspase-3, PARP, releasing cytochrome c, AIF, and Endo G from mitochondria in MIA PaCa-2 cells. Confocal laser microscopy assay also confirmed that PW06 increased Bak and decreased Bcl-xL. Also, the cells were pretreated with inhibitors of caspase-3, caspase-8, and caspase-9 and then were treated with PW06, resulting in increased viable cell number compared to PW06 treated only. Furthermore, PW06 showed a potent binding ability with hydrophobic interactions in the core site of the Fas-Fas death domains (FADD). In conclusion, PW06 can potent binding ability to the Fas-FADD which led to antiproliferative, cytotoxic activities, and apoptosis induction accompanied by the caspase-dependent and mitochondria-dependent pathways in human pancreatic cancer MIA PaCa-2 cells.

Anti-cancer peptides: their current trends in the development of peptide-based therapy and anti-tumor drugs

Human cancer remains a cause of high mortality throughout the world. The conventional methods and therapies currently employed for treatment are followed by moderate-to-severe side effects. They have not generated curative results due to the ineffectiveness of treatments. Besides, the associated high costs, technical requirements, and cytotoxicity further characterize their limitations. Due to relatively higher presidencies, bioactive peptides with anti-cancer attributes have recently become treatment choices within the therapeutic arsenal. The peptides act as potential anti-cancer agents explicitly targeting tumor cells while being less toxic to normal cells. The anti-cancer peptides are isolated from various natural sources, exhibit high selectivity and high penetration efficiency, and could be quickly restructured. The therapeutic benefits of compatible anti-cancer peptides have contributed to the significant expansion of cancer treatment; albeit, the mechanisms by which bioactive peptides inhibit the proliferation of tumor cells remain unclear. This review will provide a framework for assessing anti-cancer peptides' structural and functional aspects. It shall provide appropriate information on their mode of action to support and strengthen efforts to improve cancer prevention. The article will mention the therapeutic health benefits of anti-cancer peptides. Their importance in clinical studies is elaborated for reducing cancer incidences and developing sustainable treatment models.

Reptiles as Promising Sources of Medicinal Natural Products for Cancer Therapeutic Drugs

Natural products have historically played an important role as a source of therapeutic drugs for various diseases, and the development of medicinal natural products is still a field with high potential. Although diverse drugs have been developed for incurable diseases for several decades, discovering safe and efficient anticancer drugs remains a formidable challenge. Reptiles, as one source of Asian traditional medicines, are known to possess anticancer properties and have been used for a long time without a clarified scientific background. Recently, it has been reported that extracts, crude peptides, sera, and venom isolated from reptiles could effectively inhibit the survival and proliferation of various cancer cells. In this article, we summarize recent studies applying ingredients derived from reptiles in cancer therapy and discuss the difficulties and prospective development of natural product research.

Natural Peptides Inducing Cancer Cell Death: Mechanisms and Properties of Specific Candidates for Cancer Therapeutics

Nowadays, cancer has become the second highest leading cause of death, and it is expected to continue to affect the population in forthcoming years. Additionally, treatment options will become less accessible to the public as cases continue to grow and disease mechanisms expand. Hence, specific candidates with confirmed anticancer effects are required to develop new drugs. Among the novel therapeutic options, proteins are considered a relevant source, given that they have bioactive peptides encrypted within their sequences. These bioactive peptides, which are molecules consisting of 2–50 amino acids, have specific activities when administered, producing anticancer effects. Current databases report the effects of peptides. However, uncertainty is found when their molecular mechanisms are investigated. Furthermore, analyses addressing their interaction networks or their directly implicated mechanisms are needed to elucidate their effects on cancer cells entirely. Therefore, relevant peptides considered as candidates for cancer therapeutics with specific sequences and known anticancer mechanisms were accurately reviewed. Likewise, those features which turn certain peptides into candidates and the mechanisms by which peptides mediate tumor cell death were highlighted. This information will make robust the knowledge of these candidate peptides with recognized mechanisms and enhance their non-toxic capacity in relation to healthy cells and further avoid cell resistance.

Natural Peptides Inducing Cancer Cell Death: Mechanisms and Properties of Specific Candidates for Cancer Therapeutics

Nowadays, cancer has become the second highest leading cause of death, and it is expected to continue to affect the population in forthcoming years. Additionally, treatment options will become less accessible to the public as cases continue to grow and disease mechanisms expand. Hence, specific candidates with confirmed anticancer effects are required to develop new drugs. Among the novel therapeutic options, proteins are considered a relevant source, given that they have bioactive peptides encrypted within their sequences. These bioactive peptides, which are molecules consisting of 2–50 amino acids, have specific activities when administered, producing anticancer effects. Current databases report the effects of peptides. However, uncertainty is found when their molecular mechanisms are investigated. Furthermore, analyses addressing their interaction networks or their directly implicated mechanisms are needed to elucidate their effects on cancer cells entirely. Therefore, relevant peptides considered as candidates for cancer therapeutics with specific sequences and known anticancer mechanisms were accurately reviewed. Likewise, those features which turn certain peptides into candidates and the mechanisms by which peptides mediate tumor cell death were highlighted. This information will make robust the knowledge of these candidate peptides with recognized mechanisms and enhance their non-toxic capacity in relation to healthy cells and further avoid cell resistance.

SSTP1, a Host Defense Peptide, Exploits the Immunomodulatory IL6 Pathway to Induce Apoptosis in Cancer Cells

While the immunomodulatory pathways initiated in immune cells contribute to therapeutic response, their activation in cancer cells play a role in cancer progression. Also, many of the aberrantly expressed immunomodulators on cancer cells are considered as therapeutic targets. Here, we introduce host defense peptide (HDP), a known immuomodulator, as a therapeutic agent to target them. The cationic host defense peptides (HDPs), an integral part of the innate immune system, possess membranolytic activity, which imparts antimicrobial and antitumor efficacy to it. They act as immunomodulators by activating the immune cells. Though their antimicrobial function has been recently reassigned to immunoregulation, their antitumor activity is still attributed to its membranolytic activity. This membrane pore formation ability, which is proportional to the concentration of the peptide, also leads to side effects like hemolysis, limiting their therapeutic application. So, despite the identification of a variety of anticancer HDPs, their clinical utility is limited. Though HDPs are shown to exert the immunomodulatory activity through specific membrane targets on immune cells, their targets on cancer cells are unknown. We show that SSTP1, a novel HDP identified by shotgun cloning, binds to the active IL6/IL6Rα/gp130 complex on cancer cells, rearranging the active site residues. In contrast to the IL6 blockers inhibiting JAK/STAT activity, SSTP1 shifts the proliferative IL6/JAK/STAT signaling to the apoptotic IL6/JNK/AP1 pathway. In IL6Rα-overexpressing cancer cells, SSTP1 induces apoptosis at low concentration through JNK pathway, without causing significant membrane disruption. We highlight the importance of immunomodulatory pathways in cancer apoptosis, apart from its established role in immune cell regulation and cancer cell proliferation. Our study suggests that identification of the membrane targets for the promising anticancer HDPs might lead to the identification of new drugs for targeted therapy.

Crocodile blood supplementation protects vascular function in diabetic mice

Abstract

Cardiovascular disease is a major cause of mortality in diabetic patients due to the heightened oxidative stress and pro-inflammatory state in vascular tissues. Effective approaches targeting cardiovascular health for diabetic patients are urgently needed. Crocodile blood, an emerging dietary supplement, was suggested to have anti-oxidative and anti-inflammatory effects in vitro, which have yet to be proven in animal models. This study thereby aimed to evaluate whether crocodile blood can protect vascular function in diabetic mice against oxidation and inflammation. Diabetic db/db mice and their counterparts db/m+ mice were treated daily with crocodile blood soluble fraction (CBSF) or vehicle via oral gavage for 4 weeks before their aortae were harvested for endothelium-dependent relaxation (EDR) quantification using wire myograph, which is a well-established functional study for vascular function indication. Organ culture experiments culturing mouse aortae from C57BL/6 J mice with or without IL-1β and CBSF were done to evaluate the direct effect of CBSF on endothelial function. Reactive oxygen species (ROS) levels in mouse aortae were assessed by dihydroethidium (DHE) staining with inflammatory markers in endothelial cells quantified by quantitative polymerase chain reaction (qPCR). CBSF significantly improved deteriorated EDR in db/db diabetic mice through both diet supplementation and direct culture, with suppression of ROS level in mouse aortae. CBSF also maintained EDR and reduced ROS levels in mouse aortae against the presence of pro-inflammatory IL-1β. Under the pro-inflammatory state induced by IL-1β, gene expressions of inflammatory cytokines were downregulated, while the protective transcripts UCP2 and SIRT6 were upregulated in endothelial cells. Our study suggests a novel beneficial effect of crocodile blood on vascular function in diabetic mice and that supplementation of diet with crocodile blood may act as a complementary approach to protect against vascular diseases through anti-oxidation and anti-inflammation in diabetic patients.

Graphical abstract

Potential of crocodile blood as a medication and dietary supplement: A systemic review

Crocodile blood has long been used as a traditional medicine in many Asian countries to treat diseases such as asthma, allergies, and many others. Yet, only recently has the safety and effectiveness of using crocodile blood as a medicine been examined using modern scientific methods; with both conserved and novel active components identified from crocodile blood. Further in vitro and in vivo investigations found that crocodile blood can have a wide range of beneficial effects, including antimicrobial, antiviral, anti-oxidative, anti-inflammatory, antitumour effects, anti-anaemia, and enhancement of wound healing. A systematic research of literature published in English-language journals up to April 2020 was conducted in PubMed, Google Scholar, and Web of Science. Based on the biological and chemical knowledge of crocodile immunity and crocodile blood, this article aims to: provide a critical review on the proposed properties of crocodile blood, identify the knowledge gap and offer some insights for future investigations regarding the use of crocodile blood as a medication or dietary supplement.

Natural Products: Implication in Cancer Prevention and Treatment through Modulating Various Biological Activities

Cancer is one of the most leading causes of death worldwide. It is one of the primary global diseases that cause morbidity and mortality in millions of people. It is usually caused by different carcinogenic agents that damage the genetic material and alter the cell signaling pathways. Carcinogens are classified into two groups as genotoxic and non-genotoxic agents. Genotoxic carcinogens are capable of directly altering the genetic material, while the non-genotoxic carcinogens are capable of producing cancer by some secondary mechanisms not related to direct gene damage. There is undoubtedly the greatest need to utilize some novel natural products as anticancer agents, as these are within reach everywhere. Interventions by some natural products aimed at decreasing the levels and conditions of these risk factors can reduce the frequency of cancer incidences. Cancer is conventionally treated by surgery, radiation therapy and chemotherapy, but such treatments may be fast-acting and causes adverse effects on normal tissues. Alternative and innovative methods of cancer treatment with the least side effects and improved efficiency are being encouraged. In this review, we discuss the different risk factors of cancer development, conventional and innovative strategies of its management and provide a brief review of the most recognized natural products used as anticancer agents globally.

Gut microbiota of animals living in polluted environments are a potential resource of anticancer molecules

Cancer is a prominent cause of morbidity and mortality worldwide, in spite of advances in therapeutic interventions and supportive care. In 2018 alone, there were 18·1 million new cancer cases and 9·6 million deaths indicating the need for novel anticancer agents. Plant-based products have often been linked with protective effects against communicable and non-communicable diseases. Recently, we have shown that animals such as crocodiles thrive in polluted environments and are often exposed to carcinogenic agents, but still benefit from prolonged lifespan. The protective mechanisms shielding them from cancer could be attributed to the immune system, and/or it is possible that their gut microbiota produce anticancer molecules. In support, several lines of evidence suggest that gut microbiota plays a critical role in the physiology of its host. Here, we reviewed the available literature to assess whether the gut microbiota of animals thriving in polluted environment possess anticancer molecules.

Crocodylus porosus: a potential source of anticancer molecules

Background

Cancer remains a global threat resulting in significant morbidity and mortality despite advances in therapeutic interventions, suggesting urgency for identification of anticancer agents. Crocodiles thrive in polluted habitat, feed on germ-infested meat, are exposed to carcinogenic heavy metals, are the very few species to survive the catastrophic Cretaceous–Paleogene extinction event, yet have a prolonged lifespan and rarely been reported to develop cancer. Therefore, we hypothesised that animals living in polluted environments such as crocodiles possess anticancer molecules/mechanisms.

Methods

Crocodylus porosus was procured, blood collected, dissected and lysates prepared from internal organs. Organ lysates and sera were tested for growth inhibition, cytotoxic effects and cell survival against HeLa, PC3 and MCF7 cells and subjected to liquid chromatography mass spectrometry. RNA transcriptome analysis and differential gene analysis were performed using Galaxy Bioinformatics.

Results

Sera exhibited potent growth inhibition and cytotoxic effects against cancer cells. 80 molecules were detected from C. porosus and 19 molecules were putatively identified. Additionally, more than 100 potential anticancer peptides were identified from sera using bioinformatics based on peptide amino acid composition, binary profile, dipeptide composition and pseudo-amino acid composition. Following transcriptome analysis, 14 genes in treated HeLa cells, 51 genes in treated MCF7 cells and 2 genes in treated PC3 cells, were found to be expressed, compared with untreated controls.

Conclusion

Animals residing in polluted milieus are an unexploited source for prospective pharmaceutical drugs, and could lead to identification of novel antitumour compound(s) and/or further understanding of the mechanisms of cancer resistance.

Combinational treatment of 5-fluorouracil and casticin induces apoptosis in mouse leukemia WEHI-3 cells in vitro

Leukemia is one of the major diseases causing cancer-related deaths in the young population, and its cure rate is unsatisfying with side effects on patients. Fluorouracil (5-FU) is currently used as an anticancer drug for leukemia patients. Casticin, a natural polymethoxyflavone, exerts anticancer activity against many human cancer cell lines in vitro, but no other reports show 5-FU combined with casticin increased the mouse leukemia cell apoptosis in vitro. Herein, the antileukemia activity of 5-FU combined with casticin in WEHI-3 mouse leukemia cells was investigated in vitro. Treatment of two-drug combination had a higher decrease in cell viability and a higher increase in apoptotic cell death, the level of DNA condensation, and the length of comet tail than that of 5-FU or casticin treatment alone in WEHI-3 cells. In addition, the two-drug combination has a greater production rate of reactive oxygen species but a lower level of Ca²⁺ release and mitochondrial membrane potential (ΔΨ_m ) than that of 5-FU alone. Combined drugs also induced higher caspase-3 and caspase-8 activities than that of casticin alone and higher caspase-9 activity than that of 5-FU or casticin alone at 48 hours treatment. Furthermore, 5-FU combined with casticin has a higher expression of Cu/Zn superoxide dismutase (SOD [Cu/Zn]) and lower catalase than that of 5-FU or casticin treatment alone. The combined treatment has higher levels of Bax, Endo G, and cytochrome C of proapoptotic proteins than that of casticin alone and induced lower levels of B-cell lymphoma 2 (BCL-2) and BCL-X of antiapoptotic proteins than that of 5-FU or casticin only. Furthermore, the combined treatment had a higher expression of cleaved poly (ADP-ribose) polymerase (PARP) than that of casticin only. Based on these findings, we may suggest that 5-FU combined with casticin treatment increased apoptotic cell death in WEHI-3 mouse leukemia cells that may undergo mitochondria and caspases signaling pathways in vitro.

Fisetin Inhibits Cell Proliferation through the Induction of G0/G1 Phase Arrest and Caspase-3-Mediated Apoptosis in Mouse Leukemia Cells

Fisetin, a naturally occurring flavonoid, is found in common fruits and vegetables and has been shown to induce cytotoxic effects in many human cancer cell lines. No information has shown that fisetin induced cell cycle arrest and apoptosis in mouse leukemia WEHI-3 cells. We found that fisetin decreased total viable cells through G₀/G₁ phase arrest and induced sub-G₁ phase (apoptosis). We have confirmed fisetin induced cell apoptosis by the formation of DNA fragmentation and induction of apoptotic cell death. Results indicated that fisetin induced intracellular Ca 2+ increase but decreased the ROS production and the levels of ΔΨ m in WEHI-3 cells. Fisetin increased the activities of caspase-3, -8 and -9. Cells were pre-treated with inhibitors of caspase-3, -8 and -9 and then treated with fisetin and results showed increased viable cell number when compared to fisetin treated only. Fisetin reduced expressions of cdc25a but increased p-p53, Chk1, p21 and p27 that may lead to G₀/G₁ phase arrest. Fisetin inhibited anti-apoptotic protein Bcl-2 and Bcl-xL and increased pro-apoptotic protein Bax and Bak. Furthermore, fisetin increased the protein expression of cytochrome c and AIF. Fisetin decreased cell number through G₀/G₁ phase arrest via the inhibition of cdc25c and induction of apoptosis through caspase-dependent and mitochondria-dependent pathways. Therefore, fisetin may be useful as a potential therapeutic agent for leukemia.

Antitumor Ability of KT2 Peptide Derived from Leukocyte Peptide of Crocodile Against Human HCT116 Colon Cancer Xenografts

BACKGROUND/AIM

Many antimicrobial peptides have been shown to have anticancer activity against human cancer cell lines. Cationic KT2 peptide, derived from white blood cell extract of Crocodylus siamensis has antibacterial activity and antitumor activity against human cervical cancer cells, but there are no data on the effect of KT2 peptide on tumor growth in vivo. The anticancer activity of KT2 peptide on human colon cancer xenografts was investigated in nude mice.

MATERIALS AND METHODS

Tumors in nude mice (BALB/c -nu/nu mice) were induced by subcutaneous injection with HCT116 cells. Twelve days after cancer cell xenograft, mice were treated by intratumoral injection with phosphate-buffered saline or KT2 peptide (25 and 50 mg/kg) once every 2 days for a total of four times and mice were sacrificed at 2 days after the last treatment.

RESULTS

KT2 peptide treatment did not lead to significant difference in mouse body weight among groups, but reduced both tumor volume and weight of colon cancer xenografts. Moreover, KT2 peptide increased the expression of apoptotic proteins, such as BCL2-associated X (BAX), cleaved caspase-3, and poly (ADP-ribose) polymerase and reduced that of BCL2 apoptosis regulator in xenograft tumors.

CONCLUSION

This finding suggests that KT2 peptide may inhibit tumor growth via apoptosis induction in this mouse model and supports the antitumor ability of KT2 peptide.

Quercetin induced cell apoptosis and altered gene expression in AGS human gastric cancer cells

Quercetin is one of the natural components from natural plant and it induces cell apoptosis in many human cancer cell lines. However, no available reports show that quercetin induces apoptosis and altered associated gene expressions in human gastric cancer cells, thus, we investigated the effect of quercetin on the apoptotic cell death and associated gene expression in human gastric cancer AGS cells. Results indicated that quercetin induced cell morphological changes and reduced total viability via apoptotic cell death in AGS cells. Furthermore, results from flow cytometric assay indicated that quercetin increased reactive oxygen species (ROS) production, decreased the levels of mitochondrial membrane potential (ΔΨ_m ), and increased the apoptotic cell number in AGS cells. Results from western blotting showed that quercetin decreased anti-apoptotic protein of Mcl-1, Bcl-2, and Bcl-x but increased pro-apoptotic protein of Bad, Bax, and Bid. Furthermore, quercetin increased the gene expressions of TNFRSF10D (Tumor necrosis factor receptor superfamily, member 10d, decoy with truncated death domain), TP53INP1 (tumor protein p53 inducible nuclear protein 1), and JUNB (jun B proto-oncogene) but decreased the gene expression of VEGFB (vascular endothelial growth factor B), CDK10 (cyclin-dependent kinase 10), and KDELC2 (KDEL [Lys-Asp-Glu-Leu] containing 2) that are associated with apoptosis pathways. Thus, those findings may offer more information regarding the molecular, gene expression, and signaling pathway for quercetin induced apoptotic cell death in human gastric cancer cells.

Antitumor activity of RT2 peptide derived from crocodile leukocyte peptide on human colon cancer xenografts in nude mice

RT2, derived from the leukocyte peptide of Crocodylus siamensis, can kill human cervical cancer cells via apoptosis induction, but no evidence has shown in vivo. In this study, we investigated the antitumor effect of RT2 on human colon cancer xenografts in nude mice. Twenty-four mice were injected subcutaneously with human colon cancer HCT 116 cells. Eleven days after cancer cell implantation, the mice were treated with intratumoral injections of phosphate buffered saline (PBS) or RT2 (0.01, 0.1, and 1 mg/mouse) once every 2 days for a total of 5 times. The effect of a 10-day intratumoral injection of RT2 on body weight, biochemical, and hematological parameters in BALB/c mice showed no significant difference between the groups. Tumor volume showed a significant decrease only in the treatment group with RT2 (1 mg/mouse) at day 6 (P < .05), day 8 (P < .01), and day 10 (P < .01) after the first treatment. The protein expression levels of cleaved poly (ADP-ribose) polymerase (PARP), apoptosis-inducing factor (AIF), and the p53 tumor suppressor protein (p53) in xenograft tumors increased after treatment with RT2 (1 mg/mouse) compared to those in the PBS-injected group. Moreover, RT2 increased the expression of Endo G and Bcl-2 family proteins. Therefore, the peptide RT2 can inhibit tumor growth via the induction of apoptosis in an in vivo xenograft model.

Curcuminoids Induce Reactive Oxygen Species and Autophagy to Enhance Apoptosis in Human Oral Cancer Cells

Numerous studies support the use of herbal medicine or natural products for chemotherapy in human cancers. Reports have associated curcumin (CUR), dimethoxy curcumin (DMC) and bisdemethoxycurcumin (BDMC) with numerous biological activities including anticancer activities, but no available information have shown that these induced apoptotic cell death and autophagy in human oral cancer cells. In the present study, we investigated the effect of CUR, DMC and BDMC on the cell viability, apoptotic cell death, reactive oxygen species (ROS), Ca[Formula: see text], mitochondria membrane potential (MMP) and caspase activities using flow cytometry assay and autophagy by monodansylcadaverine (MDC) and acridine orange (AO) staining in human oral cancer SAS cells. Results indicated that CUR, DMC and BDMC decreased total viable cell number through the induction of cell autophagy and apoptosis in SAS cells. Cells were pretreated with N-acetyl-cysteine (NAC), 3-methyladenine (3MA), rapamycin and carbobenzoxy-valyl-alanyl-aspartyl-[O-methyl]-fluoro-methylketone (Z-VAD-fmk) and then were treated with CUR, DMC and BDMC that led to increased total viable cell number when compared to CUR, DMC and BDMC treatments only. Results indicated induced apoptotic cell death through ROS, mitochondria-dependent pathway and induction of cell autophagy. Based on those observations, we suggest that CUR, DMC and BDMC could be used as a potential anticancer agent in human oral cancer.

Casticin impairs cell growth and induces cell apoptosis via cell cycle arrest in human oral cancer SCC-4 cells

Casticin, a polymethoxyflavone, present in natural plants, has been shown to have biological activities including anti-cancer activities. Herein, we investigated the anti-oral cancer activity of casticin on SCC-4 cells in vitro. Viable cells, cell cycle distribution, apoptotic cell death, reactive oxygen species (ROS) production, and Ca²⁺ production, levels of ΔΨ_m and caspase activity were measured by flow cytometric assay. Cell apoptosis associated protein expressions were examined by Western blotting and confocal laser microscopy. Results indicated that casticin induced cell morphological changes, DNA condensation and damage, decreased the total viable cells, induced G₂ /M phase arrest in SCC-4 cells. Casticin promoted ROS and Ca²⁺ productions, decreases the levels of ΔΨ_m , promoted caspase-3, -8, and -9 activities in SCC-4 cells. Western blotting assay demonstrated that casticin affect protein level associated with G2/M phase arrest and apoptosis. Confocal laser microscopy also confirmed that casticin increased the translocation of AIF and cytochrome c in SCC-4 cells. In conclusion, casticin decreased cell number through G₂ /M phase arrest and the induction of cell apoptosis through caspase- and mitochondria-dependent pathways in SCC-4 cells.

Anticancer potential of bioactive peptides from animal sources (Review)

Cancer is the most common cause of human death worldwide. Conventional anticancer therapies, including chemotherapy and radiation, are associated with severe side effects and toxicities as well as low specificity. Peptides are rapidly being developed as potential anticancer agents that specifically target cancer cells and are less toxic to normal tissues, thus making them a better alternative for the prevention and management of cancer. Recent research has focused on anticancer peptides from natural animal sources, such as terrestrial mammals, marine animals, amphibians, and animal venoms. However, the mode of action by which bioactive peptides inhibit the proliferation of cancer cells remains unclear. In this review, we present the animal sources from which bioactive peptides with anticancer activity are derived and discuss multiple proposed mechanisms by which these peptides exert cytotoxic effects against cancer cells.

Bufalin induces apoptosis in vitro and has Antitumor activity against human lung cancer xenografts in vivo

Bufalin has been shown to be effective against a variety of cancer cells, but its role in lung cancer has never been studied in an animal model. In this study, we evaluated bufalin effects in a human lung cancer cell line NCI-H460 both in vitro and in vivo. Bufalin caused significant cytotoxicity in NCI-H460 cells at a concentration as low as 1 μM. DNA condensation was observed in bufalin-treated cells in a dose-dependent manner. Mitochondrial membrane potential (ΔΨ_m ) was reduced and reactive oxygen species (ROS) were increased in bufalin-treated NCI-H460 cells. Levels of several proapoptotic proteins such as Fas, Fas-ligand, cytochrome c, apoptosis protease activating factor-1, endonuclease G, caspase-3 and caspase-9 were increased after bufalin treatment. At the same time, anti-apoptotic B-cell lymphoma 2 protein levels were reduced. Bufalin decreased glucose regulated protein-78 gene expression but increased growth arrest- and DNA damage-inducible 153 gene expression. Bufalin injected intraperitoneally in a dose-dependent manner reduced tumor size in BALB/C nu/nu mice implanted with NCI-H460 cells. Bufalin injection did not produce significant drug-related toxicity in experimental animals except at a high dose (0.4 mg kg^-1 ). In conclusion, low concentrations of bufalin can induce apoptosis in the human lung cancer cell line NCI-H460 in vitro. Bufalin also reduced tumor size in mice injected with NCI-H460 cells without significant drug-related toxicity. These results indicate that bufalin may have potential to be developed as an agent for treating human non-small cell lung cancer. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1305-1317, 2017.

18α-Glycyrrhetinic Acid Induces Apoptosis of HL-60 Human Leukemia Cells through Caspases- and Mitochondria-Dependent Signaling Pathways

In this study we investigate the molecular mechanisms of caspases and mitochondria in the extrinsic and intrinsic signal apoptosis pathways in human leukemia HL-60 cells after in vitro exposure to 18α-glycyrrhetinic acid (18α-GA). Cells were exposed to 18α-GA at various concentrations for various time periods and were harvested for flow cytometry total viable cell and apoptotic cell death measurements. Cells treated with 18α-GA significantly inhibited cell proliferation and induced cell apoptosis in a dose-dependent manner, with an IC₅₀ value of 100 μM at 48 h. The cell growth inhibition resulted in induction of apoptosis and decreased the mitochondria membrane potential (ΔΨ_m) and increased caspase-8, -9 and -3 activities. Furthermore, cytochrome c and AIF were released from mitochondria, as shown by western blotting and confirmed by confocal laser microscopy. Western blotting showed that 18α-GA increased the levels of pro-apoptotic proteins such as Bax and Bid and decreased the anti-apoptotic proteins such as Bcl-2 and Bcl-xl, furthermore, results also showed that 18α-GA increased Fas and Fas-L which are associated with surface death receptor in HL-60 cells. Based on those observations, the present study supports the hypothesis that 18α-GA-induced apoptosis in HL-60 cells involves the activation of the both extrinsic and intrinsic apoptotic pathways.