Chemopreventive potential of natural compounds in head and neck cancer

Curcumin: A Potential Weapon in the Prevention and Treatment of Head and Neck Cancer

Head and neck cancers (HNC) are aggressive, difficult-to-treat tumors that can be caused by genetic factors but mainly by lifestyle or infection caused by the human papillomavirus. As the sixth most common malignancy, it presents a formidable therapeutic challenge with limited therapeutic modalities. Curcumin, a natural polyphenol, is appearing as a promising multitarget anticancer and antimetastatic agent. Numerous studies have shown that curcumin and its derivatives have the potential to affect signaling pathways (NF-κB, JAK/STAT, and EGFR) and molecular mechanisms that are crucial for the growth and migration of head and neck tumors. Furthermore, its ability to interact with the tumor microenvironment and trigger the immune system may significantly influence the organism's immune response to the tumor. Combining curcumin with conventional therapies such as chemotherapy or radiotherapy may improve the efficacy of treatment and reduce the side effects of treatment, thereby increasing its therapeutic potential. This review is a comprehensive overview that discusses both the benefits and limitations of curcumin and its therapeutic effects in the context of tumor biology, with an emphasis on molecular mechanisms in the context of HNC. This review also includes possibilities to improve the limiting properties of curcumin both in terms of the development of new derivatives, formulations, or combinations with conventional therapies that have potential as a new type of therapy for the treatment of HNC and subsequent use in clinical practice.

Chemoprevention of Head and Neck Cancer: A Review of Current Approaches and Future Perspectives

Head and neck squamous cell carcinoma (HNSCC) is a spectrum of heterogeneous malignancies. A variety of genetic, environmental, and lifestyle factors contribute to the development of HNSCC. Carcinogenesis is a multistep process in which cell proliferation-associated oncogenes and cell-cycle regulation-associated tumor suppressor genes are dysregulated, resulting in premalignant lesions. Immune evasion is a critical step in the progression of benign lesions to advanced cancer. This review discusses the advances that have been made in chemoprevention strategies for HNSCC. The rationale for the use of chemopreventive agents to inhibit head and neck cancer development is highlighted by the positive outcomes of several clinical trials. We discuss the potential of some of the commonly studied agents including vitamin A analogs, EGFR inhibitors, COX-2 inhibitors, metabolic modulators, and natural compounds such as green tea, as well as immunotherapy and photodynamic therapy to prevent HNSCC. Our review provides insight into the potential benefits of these agents and the gaps that remain to be addressed. The published results reaffirm the promise of chemoprevention in head and neck cancer and suggest that continued exploration is needed to overcome the limitations. Because the current focus on chemopreventive agents is limited, major efforts in precision oncology approaches and substantial increase in funding will promote research into chemoprevention, which will eventually decrease the incidence of HNSCC.

Phytochemicals targeting epidermal growth factor receptor (EGFR) for the prevention and treatment of HNSCC: A review

Head and neck squamous cell carcinoma (HNSCC) develops from the mucosal epithelium of the oral cavity, pharynx, and larynx, and is the most common malignancy of the head and neck, the incidence of which continues to rise. The epidermal growth factor receptor is thought to play a key role in the pathogenesis of HNSCC. Inhibition of epidermal growth factor receptor has been identified as an effective target for the treatment of HNSCC. Many phytochemicals have emerged as potential new drugs for the treatment of HNSCC. A systematic search was conducted for research articles published in PubMed, and Medline on relevant aspects. This review provides an overview of the available literature and reports highlighting the in vitro effects of phytochemicals on epidermal growth factor in various HNSCC cell models and in vivo in animal models and emphasizes the importance of epidermal growth factor as a current therapeutic target for HNSCC. Based on our review, we conclude that phytochemicals targeting the epidermal growth factor receptor are potentially effective candidates for the development of new drugs for the treatment of HNSCC. It provides an idea for further development and application of herbal medicines for cancer treatment.

Molecular pathways modulated by phytochemicals in head and neck cancer

In the last few years, natural dietary phytochemicals have shown immense potential in the suppression and incidence of Head and Neck Cancer (HNC). From various in-vitro, animal, and epidemiological studies it is now clear that intake of foods rich in dietary phytochemicals lower the risk of HNC. These phytochemicals have been reported to target different stages of Head and Neck cancer (initiation to promotion) by modulating many cellular signaling pathways. A single phytochemical may target different pathways simultaneously or a single pathway may be targeted by a diversity of phytochemicals. This review highlights the molecular pathways modulated by a large number of phytochemicals relevant to HNC with an intent to identify specific signaling pathways that could be therapeutically targeted. Therefore, relevant literature was screened and scrutinized for molecular details. We have focused on the complexity of the molecular mechanisms that are modulated by various phytochemicals and the role they can play in better clinical efficacy and management of head and neck cancer. In-depth knowledge of these molecular mechanisms can lead to innovative therapeutic strategies using phytochemicals alone or along with available treatments for various cancers including HNC. Molecular pathways modulated by Phytochemicals.

A Comprehensive Review of Natural Products as Therapeutic or Chemopreventive Agents against Head and Neck Squamous Cell Carcinoma Cells Using Preclinical Models

Head and neck squamous cell carcinoma (HNSCC) is a type of cancer that arises from the epithelium lining of the oral cavity, hypopharynx, oropharynx, and larynx. Despite the advancement of current treatments, including surgery, chemotherapy, and radiotherapy, the overall survival rate of patients afflicted with HNSCC remains poor. The reasons for these poor outcomes are due to late diagnoses and patient-acquired resistance to treatment. Natural products have been extensively explored as a safer and more acceptable alternative therapy to the current treatments, with numerous studies displaying their potential against HNSCC. This review highlights preclinical studies in the past 5 years involving natural products against HNSCC and explores the signaling pathways altered by these products. This review also addresses challenges and future directions of natural products as chemotherapeutic and chemoprevention agents against HNSCC.

Dietary Carotenoids in Head and Neck Cancer-Molecular and Clinical Implications

Head and neck cancer (HNC) is one of the most common cancers in the world according to GLOBCAN. In 2018, it was reported that HNC accounts for approximately 3% of all human cancers (51,540 new cases) and is the cause of nearly 1.5% of all cancer deaths (10,030 deaths). Despite great advances in treatment, HNC is indicated as a leading cause of death worldwide. In addition to having a positive impact on general health, a diet rich in carotenoids can regulate stages in the course of carcinogenesis; indeed, strong epidemiological associations exist between dietary carotenoids and HNS, and it is presumed that diets with carotenoids can even reduce cancer risk. They have also been proposed as potential chemotherapeutic agents and substances used in chemoprevention of HNC. The present review discusses the links between dietary carotenoids and HNC. It examines the prospective anticancer effect of dietary carotenoids against intracellular cell signalling and mechanisms, oxidative stress regulation, as well as their impact on apoptosis, cell cycle progression, cell proliferation, angiogenesis, metastasis, and chemoprevention; it also provides an overview of the limited preclinical and clinical research published in this arena. Recent epidemiological, key opinion-forming systematic reviews, cross-sectional, longitudinal, prospective, and interventional studies based on in vitro and animal models of HNC also indicate that high carotenoid content obtained from daily supplementation has positive effects on the initiation, promotion, and progression of HNC. This article presents these results according to their increasing clinical credibility.

New Scenarios in Pharmacological Treatments of Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinoma (HNSCC) is one of the most frequent types of cancer with a lethal outcome in half of the diagnosed cases. Mostly, HNSCC develops in the oral cavity, and its development is associated with tobacco and areca nut/betel quid usage, alcohol consumption, and HPV infection. Oral squamous cell carcinoma, as other head and neck cancers, presents a high degree of intratumor heterogeneity, which makes their treatment difficult, and directly correlates with drug resistance. Since the classical treatments for HNSCC oftentimes do not resolve the clinical picture, there is great need for novel therapeutic approaches, models for drug testing, and new drug delivery systems.

Combination of resveratrol and green tea epigallocatechin gallate induces synergistic apoptosis and inhibits tumor growth in vivo in head and neck cancer models

Despite widespread interest in chemoprevention and therapy due to the high margin of safety of dietary natural compounds, clinical intervention with single agents has failed to yield the expected outcomes, mostly due to poor bioavailability and low potency. Combinations of natural agents with synergistic effects are gaining increasing attention. In the present study, in vitro and in vivo antitumor effects of a combination of two natural dietary agents, green tea epigallocatechin gallate (EGCG) and resveratrol were investigated. It was revealed that their combination at low doses (at which single agents induce minimal apoptosis) synergistically increased apoptosis (combination index <1) in head and neck cancer cell lines. Synergistic apoptosis was also supported by caspase-3 and PARP cleavage. The combination also significantly inhibited growth of xenografted head and neck tumors in nude mice as supported by significant inhibition of tumor volume, tumor weight and Ki67 expression, and increase in TUNEL-positive cells. Mechanistic studies revealed that the combination inhibited AKT-mTOR signaling both in vitro and in vivo. In addition, overexpression of constitutively active AKT protected cells from apoptosis induced by the combination of EGCG and resveratrol. Collectively, the present results for the first time suggest that the combination of EGCG and resveratrol has synergistic growth inhibitory effects and provide an important rationale for future clinical development for chemoprevention and treatment of head and neck cancer.

Flavonoids Induce Migration Arrest and Apoptosis in Detroit 562 Oropharynx Squamous Cell Carcinoma Cells

Despite advances in the treatment of head and neck squamous cell carcinoma (HNSCC), the morbidity remains at a high level due to the resistance of SCC cells to chemotherapeutics. This study aimed to determine and compare the magnitude of the flavonoids’ effectiveness in activating apoptosis and migration arrest in HNSCC cells in vitro. Methods: Head and neck SCC cells of the Detroit 562 line were exposed to a range of concentrations (5–100 μM) of quercetin (Que), hesperidin (Hes) and rutin (Rut) for 24 and 48 h. The SCC cell viability and migration rate were investigated using cytotoxicity and migration inhibition assays. Muse Cell Analyzer flow cytometry was utilized to quantitatively assess the apoptosis rate of Detroit 562 cells exposed to Que, Hes and Rut. The morphology of the SCC cells was evaluated via hematoxylin-eosin staining. Results: The viability diminishment of the Detroit 562-line cells treated with Que, Hes and Rut for 48 h revealed a significant dose-dependent trend, relatively equal for three substances, whereas the most noticeable cytotoxic effect observed for Hes. Exposure to Hes and Rut exhibited a dose-dependent increased proportion of apoptotic SCC cells, at either necrosis or late apoptosis stage. Detroit 562 SCC migration rate and cells motility were halted for the 100 µM dose of Hes and Que. The comparative results elucidated that Hesperidin and Quercetin achieved a more potent reduction of Detroit 562 migration at 24 h. Conclusions: Hesperidin, rutin and quercetin are capable of inducing apoptosis and migration arrest in the Detroit 562 cell line to various extents, resulting in proapoptotic attenuating effects at different magnitudes.

Role of Endothelin 1 on Proliferation and Migration of Human MCF-7 Cells

Objective

The aim of this study was to explore the role of endothelin 1 (ET-1) in human breast cancer proliferation and migration and antagonism of endothelin receptor A (ETAR) and endothelin receptor B (ETBR) by using the non-selective dual ETA/ETB receptor antagonist bosentan and determine its anti-proliferative, anti-metastatic, and apoptotic effects demonstrated by nuclear factor kappa B (NF-kB), vascular endothelial growth factor (VEGF), Caspase 3 and Caspase 9 expression on endothelin-induced proliferation of MCF-7 cell line in vitro.

Materials and Methods

A total of 8,000 cells were seeded into e-plates 24 hours after the cells were incubated with or without 10-4 M BOS (1 hour before ET-1 treatment); 10-7, 10-8, and 10-9 M ET-1 for 1-4 days.

Results

Whether ET-1 is present or not in the tumor area, bosentan exerts anti-proliferative effect on breast cancer. However, ET-1 and bosentan group showed important inhibitory effect on tumor migration compared to bosentan alone, which can be attributed to increased activity of ET-1 axis in the presence of ET-1. The imbalance among the NF-kB, caspases, and VEGF, which are predictive factors of carcinogenesis significantly improved after bosentan administration.

Conclusion

Our study definitely demonstrated ET-1 and its critical role in cancer progression with apoptotic and anti-apoptotic pathways (NF-κB) and VEGF expression, and migration analyses were also performed. The second major finding was that bosentan inhibited ET-1-mediated effects on tumor proliferation and migration.

Molecular targeted therapy: novel therapeutic approach for head and neck cancer

Cancer is a major public health burden worldwide, affecting millions of people each year. One of the major hallmarks of cancer is rapid growth and progression by evasion of host immune responses. Tumor resistance to conventional anticancer drugs by several mechanisms, such as drug inactivation, efflux pumps and enhanced toxicity to normal cells decreases their clinical efficacy. These limitations resulted in the development of new targeted agents, such as monoclonal antibodies and small molecule inhibitors that have high tumor specificity. This paper discusses the therapeutic applications of novel molecular targeted agents and immunotherapy as an alternative treatment option for head and neck cancers, as well as provides insight into future therapeutic approaches for advanced head and neck cancers.

The Effect of Resveratrol or Curcumin on Head and Neck Cancer Cells Sensitivity to the Cytotoxic Effects of Cisplatin

Natural compounds can modulate all three major phases of carcinogenesis. The role of the natural compounds such as resveratrol (RSV) and curcumin (CRM) in modulation of anticancer potential of platinum-based drugs (CisPt) is still a topic of considerable debate. In order to enhance head and neck cancer (HNSCC) cells’ sensitivity to the cytotoxic effects of CisPt combined treatments with RSV or CRM were used. The study aim was to evaluate how the RSV or CRM associated to CisPt treatment modulated some cellular processes such as proliferation, P21 gene expression, apoptotic process, and cell cycle development in HNSCC tumor cell line (PE/CA-PJ49) compared to a normal cell line (HUVEC). The results showed that RSV or CRM treatment affected the viability of tumor cells more than normal cells. These natural compounds act against proliferation and sustain the effects of cisplatin by cell cycle arrest, induction of apoptosis and amplification of P21 expression in tumor cells. In conclusion, using RSV or CRM as adjuvants in CisPt therapy might have a beneficial effect by supporting the effects induced by CisPt.

Anti-Cancer Effect of 3-Hydroxy-β-Ionone Identified from Moringa oleifera Lam. Leaf on Human Squamous Cell Carcinoma 15 Cell Line

Squamous cell carcinoma is the most common type of head and neck cancer worldwide. Radiation and chemotherapy are general treatments for patients; however, these remedies can have adverse side effects and tumours develop drug resistance. Effective treatments still require improvement for cancer patients. Here, we investigated the anti-cancer effect of Moringa oleifera (MO) Lam. leaf extracts and their fractions, 3-hydroxy-β-ionone on SCC15 cell line. SCC15 were treated with and without MO leaf extracts and their fractions. MTT assay was used to determine cell viability on SCC15. Cell cycle and apoptosis were evaluated by the Muse™ Cell Analyser. Colony formation and wound closure analysis of SCC15 were performed in 6-well plates. Apoptosis markers were evaluated by immunoblotting. We found that Moringa extracts and 3-HBI significantly inhibited proliferation of SCC15. Moreover, they induced apoptosis and cell cycle arrest at G2/M phase in SCC15 compared to the untreated control. MO extracts and 3-HBI also inhibited colony formation and cell migration of SCC15. Furthermore, we observed the upregulation of cleaved caspase-3 and Bax with downregulation of anti-apoptotic Bcl-2, indicating the induction of cancer cell apoptosis. Our results revealed that MO extracts and 3-HBI provided anti-cancer properties by inhibiting progression and inducing apoptosis of SCC15.

Natural Products and Synthetic Analogs as a Source of Antitumor Drugs

Cancer is a heterogeneous disease and one of the major issues of health concern, especially for the public health system globally. Nature is a source of anticancer drugs with abundant pool of diverse chemicals and pharmacologically active compounds. In recent decade, some natural products and synthetic analogs have been investigated for the cancer treatment. This article presents the utilization of natural products as a source of antitumor drugs.

High olive oil diets enhance cervical tumour growth in mice: transcriptome analysis for potential candidate genes and pathways

BACKGROUND

Numerous epidemiologic studies have found a close association between obesity and cancer. Dietary fat is a fundamental contributor to obesity and is a risk factor for cancer. Thus far, the impact of dietary olive oil on cancer development remains inconclusive, and little is known about its underlying mechanisms.

METHODS

Nude mouse xenograft models were used to examine the effects of high olive oil diet feeding on cervical cancer (CC) development and progression. Cell proliferation, migration and invasion were observed by the methods of EdU incorporation, Wound healing and Transwell assay, separately. RNA-sequencing technology and comprehensive bioinformatics analyses were used to elucidate the molecular processes regulated by dietary fat. Differentially expressed genes (DEGs) were identified and were functionally analyzed by Gene Ontology (GO), Kyoto Enrichment of Genes and Genomes (KEGG). Then, protein-protein interaction (PPI) network and sub-PPI network analyses were conducted using the STRING database and Cytoscape software.

RESULTS

A high olive oil diet aggravated tumourigenesis in an experimental xenograft model of CC. Oleic acid, the main ingredient of olive oil, promoted cell growth and migration in vitro. Transcriptome sequencing analysis of xenograft tumour tissues was then performed to elucidate the regulation of molecular events regulated by dietary fat. Dietary olive oil induced 648 DEGs, comprising 155 up-regulated DEGs and 493 down-regulated DEGs. GO and pathway enrichment analysis revealed that some of the DEGs including EGR1 and FOXN2 were involved in the transcription regulation and others, including TGFB2 and COL4A3 in cell proliferation. The 15 most strongly associated DEGs were selected from the PPI network and hub genes including JUN, TIMP3, OAS1, OASL and EGR1 were confirmed by real-time quantitative PCR analysis.

CONCLUSIONS

Our study suggests that a high olive oil diet aggravates CC progression in vivo and in vitro. We provide clues to build a potential link between dietary fat and cancerogenesis and identify areas requiring further investigation.

[Combined treatment with myo-inositol and luteolin selectively suppresses growth of human lung cancer A549 cells possibly by suppressing activation of PDK1 and Akt]

OBJECTIVE

To study the effects of myo-inositol and luteolin on human lung cancer A549 cells and explore the possible mechanisms.

METHODS

A549 cells were treated with different concentrations of myo-inositol and luteolin, either alone or in combination, and the cell viability was examined using MTT assay. A549 cells and human bronchial epithelial Beas-2B cells were treated for 48 h with 10 mmol/L myo-inositol and 20 μmol/L luteolin, alone or in combination, and the cell proliferation was detected using MTT assay; the colony formation and migration of the cells were examined with colony formation assay and wound healing assay, respectively. The protein expression levels in A549 cells were detected using Western blotting.

RESULTS

Both myo-inositol and luteolin could dose-dependently inhibit the viability of A549 cells. Treatments with 10 mmol/L myo-inositol, 20 μmol/L luteolin, and both for 48 h caused significant reduction in the cell viability (92%, 83% and 70% of the control level, respectively) and colony number (79%, 73% and 43%, respectively), and significantly lowered the wound closure rate (24.61%, 13.08% and 8.65%, respectively, as compared with 29.99% in the control group). Similar treatments with myoinositol and luteolin alone or in combination produced no significant inhibitory effect on the growth, colony formation or migration of Beas-2B cells. The expressions of p-PDK1 and p-Akt in myo-inositol-treated A549 cells and the expression of pPDK1 in luteolin-treated cells were significantly decreased (P &lt; 0.05), and the decrements were more obvious in the combined treatment group (P &lt; 0.05).

CONCLUSIONS

Luteolin combined with myo-inositol can selectively inhibit the proliferation and migration of A549 cells, and these effects are probably mediated, at least in part, by suppressing the activation of PDK1 and Akt.

Identification of FOXM1 as a specific marker for triple‑negative breast cancer

The present study aimed to identify the therapeutic role of the forkhead box M1 (FOXM1)-associated pathway in triple-negative breast cancer (TNBC). Using a Cancer Landscapes-based analysis, a gene regulatory network model was constructed. The present results demonstrated that FOXM1 occupies a key position in gene networks and is a critical regulatory gene in breast cancer. Using breast carcinoma gene expression data from The Cancer Genome Atlas, it was identified that FOXM1 expression was increased in the basal-like breast cancer subtype compared with other breast cancer subtypes. RNA-sequencing analysis of MDA-MB-231 cells treated with 4 and 10 µl/ml Thiostrepton identified 662 and 5,888 significantly differentially expressed genes, respectively. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses demonstrated that FOXM1 was highly associated with multiple biological processes and was markedly associated with metabolic pathways in TNBC. The use of Search Tool for the Retrieval of Interacting Genes/Proteins provided a critical assessment and integration of protein-protein interactions, and demonstrated the multiple important functions of FOXM1 in TNBC. Real-time cell analysis, reverse transcription-quantitative polymerase chain reaction and immunofluorescence staining were used to assess the anti-tumor activity of Thiostrepton in TNBC cells in vitro. The present results identified that suppression of FOXM1 using Thiostrepton inhibited MDA-MB-231 cell proliferation and the expression of cell cycle-associated genes, including cyclin A2, cyclin B2, checkpoint kinase 1, centrosomal protein 55 and polo like kinase 1. Immunofluorescence staining analysis demonstrated that vimentin, filamentous actin and zinc finger E-box-binding homeobox 1 were all decreased following treatment with Thiostrepton. Furthermore, a BALB/C nude mouse subcutaneous xenograft model was used to verify the function of FOXM1 in vivo. The present results demonstrated that FOXM1 inhibition significantly suppressed MDA-MB-231 cell tumorigenesis in vivo. Overall, the present results suggested that FOXM1 is a key gene that serves important roles in multiple biological processes in TNBC and that it may serve as a novel therapeutic target in TNBC.

Chemopreventive role of olive oil in colon carcinogenesis by targeting noncoding RNAs and methylation machinery

Epigenetic therapy induced by dietary components has become a strong interest in the field of cancer prevention. Olive oil, a potent dietary chemopreventive agent, control colon cancer, however, its role in epigenetic therapy remains unclear. Thus, we aimed to investigate the effect of olive oil in a preclinical model of colon cancer by targeting genetic and epigenetic mechanisms. DMH was used to induce colon cancer in rats; while olive oil was given to separate group of rats along with DMH treatment. Tumor burden and incidence in DMH and DMH + olive oil-treated rats was observed by macroscopic examination and histoarchitectural studies. Potent anti-inflammatory, anti-angiogenic and pro-apoptotic activity of olive oil was explored by gene expression and immunohistochemical studies. The effect of olive oil on epigenetic alterations was examined by detecting promoter methylation with MS-HRM and dysregulation of miRNA by TaqMan MicroRNA Assay. We observed that olive oil administration lowered tumor incidence and inhibited the development of tumors in DMH-treated rats. Olive oil markedly decreased the expression of inflammatory and angiogenic markers and restored the expression of pro-apoptotic markers in DMH-treated rats. Furthermore, the inverse relationship between gene expression and DNA methylation, deviant miRNA pattern and miRNA silencing mediated by aberrant DNA methylation was also seen in DMH-treated rats, which was potentially reversible upon olive oil treatment. Our study concludes that olive oil may play a role in the epigenetic therapy by altering NF-κB and apoptotic pathways via targeting noncoding RNAs and methylation machinery that affecting epigenome to prevent colon carcinogenesis.

A Review of Promising Natural Chemopreventive Agents for Head and Neck Cancer

Head and neck squamous cell carcinoma (HNSCC) accounts for 300,000 deaths per year worldwide, and overall survival rates have shown little improvement over the past three decades. Current treatment methods including surgery, chemotherapy, and radiotherapy leave patients with secondary morbidities. Thus, treatment of HNSCC may benefit from exploration of natural compounds as chemopreventive agents. With excellent safety profiles, reduced toxicities, antioxidant properties, and general acceptance for use as dietary supplements, natural compounds are viewed as a desirable area of investigation for chemoprevention. Though most of the field is early in development, numerous studies display the potential utility of natural compounds against HNSCC. These compounds face additional challenges such as low bioavailability for systemic delivery, potential toxicities when consumed in pharmacologic doses, and acquired resistance. However, novel delivery vehicles and synthetic analogues have shown to overcome some of these challenges. This review covers 11 promising natural compounds in the chemoprevention of HNSCC including vitamin A, curcumin, isothiocyanate, green tea, luteolin, resveratrol, genistein, lycopene, bitter melon, withaferin A, and guggulsterone. The review discusses the therapeutic potential and associated challenges of these agents in the chemopreventive efforts against HNSCC. Cancer Prev Res; 11(8); 441-50. ©2018 AACR.

Tannic acid mediated induction of apoptosis in human glioma Hs 683 cells

Tannic acid (TA), a natural plant compound, is known to induce the death of cancer cells in various types of cancer. The present study was designed with the aim of exploring the effects of tannic acid in vitro on HS 683, a glioma cell line, and to study the mechanism involved in the induction of cytotoxicity and apoptosis by TA. TA exhibited maximum cytotoxic activity against the Hs 683 cell line. Nuclear morphology, 4′,6-diamidino-2-phenylindole staining and annexin V/propidium iodide apoptosis assaying of Hs 683 cells confirmed that cell death was due to the induction of apoptosis by TA. Further mechanistic study of TA on Hs 683 cells revealed that it decreased cell growth with increasing TA concentration, that resulted in the activation of pro-caspase 3 and caspase 9 and the cleavage of poly (ADP-ribose) polymerase, implying the induction of apoptosis cascades. Biochemical evidence of apoptosis resulted from the loss of mitochondrial membrane potential and increased intracellular reactive oxygen species production by TA in a dose-dependent manner. Based on this data, TA may be further investigated as a potential anticancer therapeutic lead.

Icaritin Reduces Oral Squamous Cell Carcinoma Progression via the Inhibition of STAT3 Signaling

Icaritin, a traditional Chinese medicine, possesses antitumor activity. The current study aimed to investigate icaritin effect and potential mechanism on oral squamous cell carcinoma (OSCC) development. OSCC cells proliferation, apoptosis, and autophagy were analyzed after incubation with icaritin at different concentrations and incubation times. The expressions of proteins related to proliferation, apoptosis, and autophagy, as well as signal transducer and activator of transcription 3 (STAT3) signal network, were also evaluated by western blot. Furthermore, STAT3 was knocked down by siRNA transfection to determine STAT3 role in OSCC cell proliferation and apoptosis. An oral specific carcinogenesis mouse model was used to explore icaritin effect on OSCC in vivo. Icaritin significantly inhibited OSCC proliferation in vitro and reduced the expression of both the cell-cycle progression proteins cyclin A2 and cyclin D1. Besides, icaritin increased cleaved caspase 3 and cleaved poly-(ADP-ribose) polymerase expression leading to apoptosis, and it activated autophagy. Icaritin significantly inhibited the expression of phospho-STAT3 (p-STAT3) in a dose- and time-dependent manner. In the in vivo experiment, the number of malignant tumors in the icaritin-treated group was significantly lower than the control. Overall, icaritin suppressed proliferation, promoted apoptosis and autophagy, and inhibited STAT3 signaling in OSCC in vitro and in vivo. In conclusion, icaritin might be a potential therapeutic agent against OSCC development.

Cantharidin Induced Oral Squamous Cell Carcinoma Cell Apoptosis via the JNK-Regulated Mitochondria and Endoplasmic Reticulum Stress-Related Signaling Pathways

Oral cancer is a subtype of head and neck cancer which represents 2.65% of all human malignancies. Most of oral cancer is histopathologically diagnosed as oral squamous cell carcinoma (OSCC). OSCC is characterized by a high degree of local invasion and a high rate of metastasis to the cervical lymph nodes. How to prevention and treatment of OSCC is important and imperative. Here, we investigated the therapeutic effect and molecular mechanism of cantharidin, an active compound isolated from blister beetles, on OSCC in vitro. Results showed that cantharidin significantly decreased cell viability in human tongue squamous carcinoma-derived SAS, CAL-27, and SCC-4 cell lines. The further mechanistic studies were carried out in SAS cells. Cantharidin also significantly increased apoptosis-related signals, including caspase-9, caspase-7 and caspase-3 proteins. Besides, cantharidin decreased mitochondrial transmembrane potential (MMP) and induced cytochrome c and apoptosis inducing factor (AIF) release. Cantharidin also increased Bax, Bid, and Bak protein expressions and decreased Bcl-2 protein expression. Cantharidin could also increase the endoplasmic reticulum (ER) stress signals, including the expressions of phosphorylated eIF-2α and CHOP, but not Grp78 and Grp94. Furthermore, cantharidin reduced pro-caspase-12 protein expression. In signals of mitogen-activated protein kinases, cantharidin increased the phosphorylation of JNK, but not ERK and p38. Transfection of shRNA-JNK to OSCC cells effectively reversed the cantharidin-induced cell apoptotic signals, including the mitochondrial and ER stress-related signaling molecules. Taken together, these findings suggest that cantharidin induces apoptosis in OSCC cells via the JNK-regulated mitochondria and ER stress-related signaling pathways.

Cellular uptake and anticancer activity of salvianolic acid B phospholipid complex loaded nanoparticles in head and neck cancer and precancer cells

Salvianolic acid B (SalB) was demonstrated to be a promising chemopreventive agent for head and neck squamous cell carcinoma (HNSCC) in the previous studies by our and other research institution, but the properties like low efficacy, poor systemic delivery, and low bioavailability has hampered its clinical applications. To continue our research program focused on the use of natural compounds on cancer chemoprevention, we propose a first example of phospholipid complex loaded nanoparticles (PLC-NPs) encapsulating SalB as a potential carrier for intervention of HNSCC (HN13, HN30) cells and precancer Leuk1 cells in this study. Qualitative and quantitive studies of cellular uptake showed that intracellular accumulation of SalB was significantly higher when HN13, HN30 and Leuk1 cells were incubated with SalB-PLC-NPs complex (nano-SalB) as against free-SalB. Cell viability assay revealed that the cell growth of HN13 and HN30 cells was significantly inhibited of 56.1% and 29.3%, respectively, for nano-SalB compared to an equivalent amount of free-SalB (P<0.001). Moreover, cell cycle and apoptosis assay showed that a clear trend of cell cycle arrest and induction of apoptosis was also observed within the HNSCC cells treated with nano-SalB. Collectively, this study demonstrated that nano-SalB was significantly more potent had an anticancer effect against HNSCC cells, which serves as the first step toward establishing SalB nano-formulations as promising cancer chemopreventive agents. The current study could pave a new way for the development of drugs that target HNSCC in the future.

Acetylshikonin inhibits growth of oral squamous cell carcinoma by inducing apoptosis

OBJECTIVES

Recently, shikonin derivatives from Lithospermum erythrorhizon have been suggested as potential chemotherapeutic agents against numerous types of cancers in addition to their traditional uses, e.g., as anti-inflammatory agents. Acetylshikonin, one of shikonin derivatives, has also been reported to possess anticancer activity. However, few studies of the effectiveness of acetylshikonin against cancer cells have been conducted, and there are no studies of oral cancers. In this study, we investigated the usefulness of acetylshikonin as a treatment regimen for oral cancers by observing the growth inhibitory function of acetylshikonin and the involved mechanisms.

DESIGNS

The viability, cell cycle, and ratio of apoptotic cells of oral squamous cell carcinoma (OSCC) cells were observed after treatment with acetylshikonin using MTT assay, flow cytometric analysis, and Annexin V/PI staining, respectively. In addition, molecular changes of apoptosis-related pathways and the role of reactive oxygen species (ROS) were analyzed in acetylshikonin-treated cells.

RESULTS

We observed that acetylshikonin significantly suppressed the growth of OSCC cells by inducing apoptotic cell death, and acetylshikonin affected the viability of a normal keratinocyte cell line HaCaT to a lesser degree, suggesting that acetylshikonin may be a good chemotherapeutic reagent with less toxicity to normal tissues. In addition, we found that acetylshikonin-induced apoptosis of OSCC cells is mediated by ROS as well as G2 cell cycle arrest. ROS production in response to acetylshikonin treatment enhanced the phosphorylation of JNK and p38 MAPK, which are in the major pathways of apoptotic cell death mechanisms.

CONCLUSIONS

In summary, our data suggest that acetylshikonin is a strong candidate for use as a selective chemotherapeutic agent for the treatment of OSCC.

Co-targeting of Cyclooxygenase-2 and FoxM1 is a viable strategy in inducing anticancer effects in colorectal cancer cells

Background

Cross-talk between deregulated signaling pathways in cancer cells causes uncontrolled growth and proliferation. These cancers cells become more aggressive and quickly develop resistance to therapy. Therefore targeting of these deregulated pathways simultaneously can result in efficient cell death of cancer cells. In this study we investigated co-expression of Cox-2 and FoxM1 in a cohort of colorectal carcinoma (CRC) samples and also examined whether inhibition of Cox-2 and FoxM1 simultaneously can lead to inhibition of cell viability and induction of apoptosis in colorectal cancer cell lines and in vivo xenografts.

Methods

Protein expression of Cox-2 and FoxM1 was determined in a large cohort of 770 clinical CRC samples in a tissue micro-array format by immunohistochemistry. Cell death was measured using live dead assay. Apoptosis was measured by annexin V/PI dual staining. Immunoblotting was performed to examine the expression of proteins. Calcusyn software was utilized to estimate the synergistic doses using chou and Talalay method.

Results

Co-expression of Cox-2 and FoxM1 was detected in 33.3 % (232/697) of CRC’s and associated with an aggressive phenotype characterized by younger age (p = 0.0191), high proliferative index marker; Ki-67 (p = 0.004) and MMP-9 (p = 0.0116) as well as activation of AKT (p = 0.0214). In vitro, inhibition of FoxM1 and Cox-2 with pharmacological inhibitors; Thiostrepton and NS398 resulted in efficient down-regulation of FoxM1 and Cox-2 expression along with in-activation of AKT and inhibition of colony formation, invasion and migratory capability of CRC cells. In addition, there was also inhibition of cell viability and induction of apoptosis via the mitochondrial apoptotic pathway in CRC cell lines. Finally, treatment of CRC xenograft tumors in nude mice with combination of Cox-2 and FoxM1 inhibitors inhibited tumor growth significantly via down-regulation of Cox-2 and FoxM1 expression.

Conclusions

These findings demonstrate that co-expression of Cox-2 and FoxM1 might play a critical role in the pathogenesis of CRC. Therefore, targeting of these pathways simultaneously with sub toxic doses of pharmacological inhibitors can be a potential therapeutic approach for the treatment of this subset of CRC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0406-1) contains supplementary material, which is available to authorized users.

FLLL12 induces apoptosis in lung cancer cells through a p53/p73-independent but death receptor 5-dependent pathway

Unlike chemotherapy drugs, the safety of natural compounds such as curcumin has been well established. However, the potential use of curcumin in cancer has been compromised by its low bioavailability, limited tissue distribution and rapid biotransformation leading to low in vivo efficacy. To circumvent these problems, more potent and bioavailable analogs have been synthesized. In the current study, we investigated the mechanism of anti-tumor effect of one such analog, FLLL12, in lung cancers. IC50 values measured by sulforhodamine B (SRB) assay at 72 h and apoptosis assays (annexin V staining, cleavage of PARP and caspase-3) suggest that FLLL12 is 5-10-fold more potent than curcumin against a panel of premalignant and malignant lung cancer cell lines, depending on the cell line. Moreover, FLLL12 induced the expression of death receptor-5 (DR5). Ablation of the expression of the components of the extrinsic apoptotic pathway (DR5, caspase-8 and Bid) by siRNA significantly protected cells from FLLL12-induced apoptosis (p < 0.05). Analysis of mRNA expression revealed that FLLL-12 had no significant effect on the expression of DR5 mRNA expression. Interestingly, inhibition of global phosphatase activity as well as protein tyrosine phosphatases (PTPs), but not of alkaline phosphatases, strongly inhibited DR5 expression and significantly inhibited apoptosis (p < 0.05), suggesting the involvement of PTPs in the regulation of DR5 expression and apoptosis. We further showed that the apoptosis is independent of p53 and p73. Taken together, our results strongly suggest that FLLL12 induces apoptosis of lung cancer cell lines by posttranscriptional regulation of DR5 through activation of protein tyrosine phosphatase(s).

Effect of the coffee ingredient cafestol on head and neck squamous cell carcinoma cell lines

BACKGROUND AND PURPOSE

Cafestol is a diterpene molecule found in coffee beans and has anticarcinogenic properties. The aim of the study was to examine the effects of cafestol in head and neck squamous cell carcinoma (HNSCC) cells.

MATERIALS AND METHODS

Three HNSCC cell lines (SCC25, CAL27 and FaDu) were treated with increasing doses of cafestol. Then combination experiments with cisplatin and irradiation were carried out. Drug interactions and possible synergy were calculated using the combination index analysis. Clonogenic assays were performed after irradiation with 2, 4, 6 and 8 Gy, respectively, and the rate of apoptosis was measured with flow cytometry.

RESULTS

Treatment of HNSCC cells with cafestol leads to a dose-dependent reduction of cell viability and to induction of apoptosis. Combination with irradiation shows a reduction of clonogenic survival compared to each treatment method alone. In two of the cell lines a significant additive effect was observed.

CONCLUSION

Cafestol is a naturally occurring effective compound with growth-inhibiting properties in head and neck cancer cells. Moreover, it leads to a significant inhibition of colony formation.

Association of cancer metabolism-related proteins with oral carcinogenesis - indications for chemoprevention and metabolic sensitizing of oral squamous cell carcinoma?

Background

Tumor metabolism is a crucial factor for the carcinogenesis of oral squamous cell carcinoma (OSCC).

Methods

Expression of IGF-R1, glycolysis-related proteins (GLUT-1, HK 2, PFK-1, LDHA, TKTL1), mitochondrial enzymes (SDHA, SDHB, ATP synthase) were analyzed in normal oral mucosa (n = 5), oral precursor lesions (simple hyperplasia, n = 11; squamous intraepithelial neoplasia, SIN I-III, n = 35), and OSCC specimen (n = 42) by immunohistochemistry and real-time polymerase chain reaction (qPCR) analysis in OSCC cell lines. Metabolism-related proteins were correlated with proliferation activity (Ki-67) and apoptotic properties (TUNEL assay) in OSCC. Specificity of antibodies was confirmed by western blotting in cancer cell lines.

Results

Expression of IGF-R1, glycolysis-related proteins (GLUT-1, HK 2, LDHA, TKTL1), and mitochondrial enzymes (SDHA, SDHB, ATP synthase) were significantly increased in the carcinogenesis of OSCC. Metabolic active regions of OSCC were strongly correlated with proliferating cancer (Ki-67+) cells without detection of apoptosis (TUNEL assay).

Conclusions

This study provides the first evidence of the expression of IGF-R1, glycolysis-related proteins GLUT-1, HK 2, PFK-1, LDHA, and TKTL1, as well as mitochondrial enzymes SDHA, SDHB, and ATP synthase in the multi-step carcinogenesis of OSCC. Both, hypoxia-related glucose metabolism and mitochondrial oxidative phosphorylation characteristics are associated with the carcinogenesis of OSCC. Acidosis and OXPHOS may drive a metabolic shift towards the pentose phosphate pathway (PPP). Therefore, inhibition of the PPP, glycolysis, and targeted anti-mitochondrial therapies (ROS generation) by natural compounds or synthetic vitamin derivatives may act as sensitizer for apoptosis in cancer cells mediated by adjuvant therapies in OSCC.

Chemoprevention of head and neck squamous cell carcinoma through inhibition of NF-κB signaling

Nuclear factor-kappa B (NF-κB) transcription factors regulate cellular processes such as inflammation and cell survival. The NF-κB pathway is often activated with development and progression of head and neck squamous cell carcinoma (HNSCC). As such, NF-κB represents an attractive target for chemoprevention. HNSCC involves progression of lesions from premalignant to malignant, providing a window of opportunity for intervention with chemopreventive agents. Appropriate chemopreventive agents should be inexpensive, nontoxic, and target important pathways involved in the development of HNSCC. Several such agents that inhibit the NF-κB pathway have been investigated in HNSCC. Retinoids have been studied most extensively but have shown limited potential in human trials. Epidermal growth factor receptor inhibitors and PI3K-mTOR inhibitors may benefit a subset of patients. Other agents such as green tea extract and curcumin are appealing because they are generally regarded as safe. In contrast, there is evidence that Vitamin E supplementation may actually increase mortality of cancer patients. Repurposed drugs such as cyclooxygenase (COX) inhibitors and antidiabetic drugs are an emerging area of interest. Future research to develop agents with lower toxicity and higher specificity for the NF-κB pathway, and to target these therapies to individual patient genetic signatures should help to increase the utility of chemoprevention in HSNCC.

Correlation of Notch1, pAKT and nuclear NF-κB expression in triple negative breast cancer

Gene expression profiling reveals elevated Notch1 mRNA expression in triple negative breast cancers (TNBC), both basaloid and claudin-low subtypes. Notch ligands, Jagged1 and Jagged2, have been correlated with poor prognosis in TNBC. AKT, an oncogenic protein kinase family that is activated downstream of Notch in breast cancer cell lines, is frequently activated in breast cancer. Recent publications suggest that inhibition of cell growth, migration, invasion, and induction of apoptosis caused by Notch1 or Jagged1 inhibition may be attributed in part to inactivation of the AKT signaling pathway. There is significant evidence that Notch1 activates NF-κB in several models, and that AKT can mediate NF-κB activation. In this study, we evaluated Notch1 protein expression by immunohistochemistry (IHC) and correlated this with expression of pAKT and nuclear NF-κB p65 (RelA) in TNBC. A tissue microarray (TMA) containing 32 formalin-fixed, paraffin-embedded (FFPE) TNBC tumor specimens was constructed from the archival tissue database of the Department of Pathology at UMMC and IHC for Notch1 protein, pAKT 1/2/3 (Ser473), and NF-κB, p65 subunit was performed on the TMA with appropriate positive and negative controls. Of the 32 TNBC in our cohort, 100% expressed Notch1 protein by IHC: 24 (75%) showed cytoplasmic expression, 25 (78%) showed membranous expression, and 17 (53%) showed both cytoplasmic and membranous expression. Overall, 29 (91%) expressed pAKT by IHC: 28 (97%) showed cytoplasmic expression, 14 (48%) showed nuclear expression and 13 (45%) showed both cytoplasmic and nuclear expression. Nuclear staining for NF-κB p65 was detected in all 32 TNBC specimens with variable intensities. On bivariate analysis, cytoplasmic Notch1 was significantly correlated with cytoplasmic pAKT (r = 0.373, P = 0.035) and nuclear NF-κB (r = 0.483, P = 0.005); both cytoplasmic and nuclear pAKT significantly correlated with nuclear NF-κB (r = 0.391, P = 0.027; r = 0.525, P = 0.002, respectively). These results suggest that 1) the cross-talk between Notch1, AKT and NF-κB identified in preclinical models may operate in a significant fraction of human TNBC, and 2) combination therapy with agents targeting these pathways warrants further investigation.

Aminoglycosylation can enhance the G-quadruplex binding activity of epigallocatechin

With the aim of enhancing G-quadruplex binding activity, two new glucosaminosides (16, 18) of penta-methylated epigallocatechin were synthesized by chemical glycosylation. Subsequent ESI-TOF-MS analysis demonstrated that these two glucosaminoside derivatives exhibit much stronger binding activity to human telomeric DNA and RNA G-quadruplexes than their parent structure (i.e., methylated EGC) (14) as well as natural epigallocatechin (EGC, 6). The DNA G-quadruplex binding activity of 16 and 18 is even more potent than strong G-quadruplex binder quercetin, which has a more planar structure. These two synthetic compounds also showed a higher binding strength to human telomeric RNA G-quadruplex than its DNA counterpart. Analysis of the structure-activity relationship revealed that the more basic compound, 16, has a higher binding capacity with DNA and RNA G-quadruplexes than its N-acetyl derivative, 18, suggesting the importance of the basicity of the aminoglycoside for G-quadruplex binding activity. Molecular docking simulation predicted that the aromatic ring of 16 π-stacks with the aromatic ring of guanine nucleotides, with the glucosamine moiety residing in the groove of G-quadruplex. This research indicates that glycosylation of natural products with aminosugar can significantly enhance their G-quadruplex binding activities, thus is an effective way to generate small molecules targeting G-quadruplexes in nucleic acids. In addition, this is the first report that green tea catechin can bind to nucleic acid G-quadruplex structures.

Cancer prevention with promising natural products: mechanisms of action and molecular targets

Cancer is the second leading cause of death worldwide. There is greater need for more effective and less toxic therapeutic and preventive strategies. Natural products are becoming an important research area for novel and bioactive molecules for drug discovery. Phytochemicals and dietary compounds have been used for the treatment of cancer throughout history due to their safety, low toxicity, and general availability. Many active phytochemicals are in human clinical trials. Studies have indicated that daily consumption of dietary phytochemicals have cancer protective effects against carcinogens. They can inhibit, delay, or reverse carcinogenesis by inducing detoxifying and antioxidant enzymes systems, regulating inflammatory and proliferative signaling pathways, and inducing cell cycle arrest and apoptosis. Epidemiological studies have also revealed that high dietary intakes of fruits and vegetables reduce the risk of cancer. This review discusses potential natural cancer preventive compounds, their molecular targets, and their mechanisms of actions.

Plants vs. cancer: a review on natural phytochemicals in preventing and treating cancers and their druggability

Cancer remains to be one of the leading causes of death in the United States and around the world. The advent of modern drug-targeted therapies has undeniably improved cancer patients' cares. However, advanced metastasized cancer remains untreatable. Hence, continued searching for a safer and more effective chemoprevention and treatment is clearly needed for the improvement of the efficiency and to lower the treatment cost for cancer care. Cancer chemoprevention with natural phytochemical compounds is an emerging strategy to prevent, impede, delay, or cure cancer. This review summarizes the latest research in cancer chemoprevention and treatment using the bioactive components from natural plants. Relevant molecular mechanisms involved in the pharmacological effects of these phytochemicals are discussed. Pharmaceutical developmental challenges and opportunities in bringing the phytochemicals into the market are also explored. The authors wish to expand this research area not only for their scientific soundness, but also for their potential druggability.

Bak is a key molecule in apoptosis induced by methanol extracts of Codonopsis lanceolata and Tricholoma matsutake in HSC-2 human oral cancer cells

Since the 5-year survival rate of oral cancer remains low, more effective and non-toxic therapeutic and preventive strategies are required. Certain natural products possess anti-cancer properties. The present study investigated the effects of the methanol extracts of Codonopsis lanceolata (MECI) and Tricholoma matsutake (METM) and identified the molecular target in HSC-2 human oral cancer cells. The results revealed that MECI and METM inhibited growth and induced apoptosis, as demonstrated by poly (ADP-ribose) polymerase (PARP) cleavage and nuclear condensation and fragmentation. The compounds also increased Bak protein expression, while Bax, Bcl-XL and Mcl-1 were not affected. The results of the present study show that MECI and METM induce apoptosis to inhibit tumor growth of HSC-2 cells by modulating the Bak protein and suggest that Codonopsis lanceolata and Tricholoma matsutake are potential anticancer drug candidates for oral cancer.

Food-related compounds that modulate expression of inducible nitric oxide synthase may act as its inhibitors

Natural compounds commonly found in foods may contribute to protect cells against the deleterious effects of inflammation. These anti-inflammatory properties have been linked to the modulation of transcription factors that control expression of inflammation-related genes, including the inducible nitric oxide synthase (iNOS), rather than a direct inhibitory action on these proteins. In this study, forty two natural dietary compounds, known for their ability to exert an inhibitory effect on the expression of iNOS, have been studied in silico as docking ligands on two available 3D structures for this protein (PDB ID: 3E7G and PDB ID: 1NSI). Natural compounds such as silibinin and cyanidin-3-rutinoside and other flavonoids showed the highest theoretical affinities for iNOS. Docking affinity values calculated for several known iNOS inhibitors significatively correlated with their reported half maximal inhibitory concentrations (R = 0.842, P < 0.0001), suggesting the computational reliability of the predictions made by our docking simulations. Moreover, docking affinity values for potent iNOS inhibitors are of similar magnitude to those obtained for some studied natural products. Results presented here indicate that, in addition to gene expression modulation of proteins involved in inflammation, some chemicals present in food may be acting by direct binding and possible inhibiting actions on iNOS.

Cross-talk between NFkB and the PI3-kinase/AKT pathway can be targeted in primary effusion lymphoma (PEL) cell lines for efficient apoptosis

Background

A number of constitutively activated signaling pathways play critical roles in the survival and growth of primary effusion lymphoma cells (PELs) including NFkB and PI3/AKT kinase cascades. NFkBis constitutively activated in a number of malignancies, including multiple myeloma, Burkitt’s lymphoma and diffuse large cell B-cell lymphoma. However, its role in primary effusion lymphoma has not been fully explored.

Methodology/Principal Findings

We used pharmacological inhibition and gene silencing to define the role of NFkB in growth and survival of PEL cells. Inhibition of NFkB activity by Bay11-7085 resulted in decreased expression of p65 in the nuclear compartment as detected by EMSA assays. In addition, Bay11-7085 treatment caused de-phosphorylation of AKT and its downstream targets suggesting a cross-talk between NFkB and the PI3-kinase/AKT pathway. Importantly, treatment of PEL cells with Bay11-7085 led to inhibition of cell viability and induced apoptosis in a dose dependent manner. Similar apoptotic effects were found when p65 was knocked down using specific small interference RNA. Finally, co-treatment of PEL cells with suboptimal doses of Bay11-7085 and LY294002 led to synergistic apoptotic responses in PEL cells.

Conclusion/Significance

These data support a strong biological-link between NFkB and the PI3-kinase/AKT pathway in the modulation of anti-apoptotic effects in PEL cells. Synergistic targeting of these pathways using NFKB- and PI3-kinase/AKT- inhibitors may have a therapeutic potential for the treatment of PEL and possibly other malignancies with constitutive activation of these pathways.

Plant phytochemicals as new potential drugs for immune disorders and cancer therapy: really a promising path?

Plant phytochemicals represent an exciting opportunity to maintain best health conditions through a balanced and properly administered daily nutrition or dietary supplement and have often been considered a good option for obtaining a few promising, expensive new drugs from plants. Several polyphenolic compounds, such as resveratrol, tea catechins and flavonoids, which are commonly found in vegetables, fruits and plant-derived juices or beverages, exert well-evidenced cardioprotective, neuroprotective, chemopreventive and anti-inflammatory properties, but, nevertheless, further clinical and epidemiological research is required. Most of these botanical byproducts are produced as noxious components by plants, in order to prevent pathogen colonization, insect-mediated damage and also to discourage animals from eating them. An evolutionary theory of stress adaptation would explain how these toxic substances from nature act as protective molecules. A future challenge to achieve a rather complete understanding of these chemical phenol derivatives for human health should deal with the complexity of cellular signalling networks, the epigenetic machinery endowment of the cell and the nonlinear relationship between dose and effectiveness.

Curcumin and other polyphenolic compounds in head and neck cancer chemoprevention

Despite clear results of observational studies linking a diet rich in fruits and vegetables to a decreased cancer risk, large interventional trials evaluating the impact of dietary micronutrient supplementation, mostly vitamins, could not show any beneficial effects. Today it has become clear that a single micronutrient, given in supernutritional doses, cannot match cancer preventive effects of whole fruits and vegetables. In this regard polyphenols came into focus, not only because of their antioxidant potential but also because of their ability to interact with molecular targets within the cells. Because polyphenols occur in many foods and beverages in high concentration and evidence for their anticancer activity is best for tissues they can come into direct contact with, field cancerization predestines upper aerodigestive tract epithelium for cancer chemoprevention by polyphenols. In this paper, we summarize cancer chemopreventive attempts with emphasis on head and neck carcinogenesis and discuss some methodological issues. We present data regarding antimutagenic effects of curcumin and epigallocatechin-3-gallate in human oropharyngeal mucosa cultures exposed to cigarette smoke condensate.

Chemoprotective effects of carnosine against genotoxicity induced by cyclophosphamide in mice bone marrow cells

The protective effects of carnosine as a natural dipeptide were investigated in mouse bone marrow cells against genotoxicity induced by cyclophosphamide. Mice were injected with solutions of carnosine at three different doses (10, 50 and 100 mg kg(-1) bw) for five consecutive days. On the fifth day of treatment, mice were injected cyclophosphamide and killed after 24 h. The frequency of micronuclei in polychromatic erythrocytes and the ratio of polychromatic erythrocyte/polychromatic erythrocyte + normochromatic erythrocyte [PCE/(PCE + NCE)] were evaluated by May-Grunwald/Giemsa staining. Histopathology of bone marrow was examined in mice treated with cyclophosphamide and carnosine. Carnosine significantly reduced micronucleated polychromatic erythrocytes (MnPCEs) induced by cyclophosphamide at all three doses. Carnosine at dose of 100 mg kg(-1) bw reduced MnPCEs 3.76-fold and completely normalized the PCE/(PCE + NCE) ratio. Administration of carnosine inhibited bone marrow toxicity induced by cyclophosphamide. It appeared that carnosine with protective activity reduced the oxidative stress and genotoxicity induced by cyclophosphamide in bone marrow cells of mice.

Nutrigenomics and Cancer Prevention

Mounting evidence continues to point to dietary habits as a modifier of cancer risk and tumor behavior; although it is clear that considerable variability occurs across studies. While genetic public health messages can be developed, the use of mean values may result in underexposure to some essential and nonessential food components, yet precipitate overexposure to nutrients. Undeniably, inconsistencies in the literature may reflect variation in timing of exposures to specific dietary constituents, interactions with the food matrix, processing technologies, or the genomic variation among individuals, which can influence absorption, metabolism, and/or the molecular target. Inter-individual variability in genetics, epigenetics, transcriptomics, proteomics, metabolomics, or microbiomics can influence the magnitude and direction of response to bioactive food components, as briefly reviewed in this article. Unquestionably, understanding nutrigenomics holds promise to reveal those who will benefit most from dietary interventions plus identify any who might be placed at risk due to overexposures.

Fucoidan from Sargassum sp. and Fucus vesiculosus reduces cell viability of lung carcinoma and melanoma cells in vitro and activates natural killer cells in mice in vivo

Fucoidan is known to exhibit crucial biological activities, including anti-tumor activity. In this study, we examined the influence of crude fucoidan extracted from Sargassum sp. (MTA) and Fucus vesiculosus (SIG) on Lewis lung carcinoma cells (LCC) and melanoma B16 cells (MC). In vitro studies were performed using cell viability analysis and showed that SIG and MTA fucoidans significantly decreased the viable number of LCC and MC cells in a dose-response fashion. Histochemical staining showed morphological changes of melanoma B16 cells after exposure to fucoidan. The observed changes were indicative of crude fucoidan induced apoptosis. Male C57BL/6JJCL mice were subjected to daily i.p. injections over 4 days with either SIG or MTA fucoidan (50mg/kg body wt.). The cytolytic activity of natural killer (NK) cells was enhanced by crude fucoidan in a dose-dependent manner as indicated by (51)Cr labeled YAC-1 target cell release. This study provides substantial indications that crude fucoidan exerts bioactive effects on lung and skin cancer model cells in vitro and induces enhanced natural killer cell activity in mice in vivo.

Enhancing photodynamyc therapy efficacy by combination therapy: dated, current and oncoming strategies

Combination therapy is a common practice in many medical disciplines. It is defined as the use of more than one drug to treat the same disease. Sometimes this expression describes the simultaneous use of therapeutic approaches that target different cellular/molecular pathways, increasing the chances of killing the diseased cell. This short review is concerned with therapeutic combinations in which PDT (Photodynamyc Therapy) is the core therapeutic partner. Besides the description of the principal methods used to assess the efficacy attained by combinations in respect to monotherapy, this review describes experimental results in which PDT was combined with conventional drugs in different experimental conditions. This inventory is far from exhaustive, as the number of photosensitizers used in combination with different drugs is very large. Reports cited in this work have been selected because considered representative. The combinations we have reviewed include the association of PDT with anti-oxidants, chemotherapeutics, drugs targeting topoisomerases I and II, antimetabolites and others. Some paragraphs are dedicated to PDT and immuno-modulation, others to associations of PDT with angiogenesis inhibitors, receptor inhibitors, radiotherapy and more. Finally, a look is dedicated to combinations involving the use of natural compounds and, as new entries, drugs that act as proteasome inhibitors.