Garcinol sensitizes human head and neck carcinoma to cisplatin in a xenograft mouse model despite downregulation of proliferative biomarkers

Pharmacological Utilization of Bergamottin, Derived from Grapefruits, in Cancer Prevention and Therapy

Cancer still remains one of the leading causes of death worldwide. In spite of significant advances in treatment options and the advent of novel targeted therapies, there still remains an unmet need for the identification of novel pharmacological agents for cancer therapy. This has led to several studies evaluating the possible application of natural agents found in vegetables, fruits, or plant-derived products that may be useful for cancer treatment. Bergamottin is a furanocoumarin derived from grapefruits and is also a well-known cytochrome P450 inhibitor. Recent studies have demonstrated potent anti-oxidative, anti-inflammatory, and anti-cancer properties of grapefruit furanocoumarin both in vitro and in vivo. The present review focuses on the potential anti-neoplastic effects of bergamottin in different tumor models and briefly describes the molecular targets affected by this agent.

N-Substituted Pyrido-1,4-Oxazin-3-Ones Induce Apoptosis of Hepatocellular Carcinoma Cells by Targeting NF-κB Signaling Pathway

Hepatocellular carcinoma (HCC) is a fatal disease and ranked fifth in cancer related mortality. Persistent activation of NF-κB is responsible for the oncogenesis, metastasis, tumor evasion, anti-apoptosis, angiogenesis and proliferation in HCC. Therefore, designing of chemically novel, biologically potent small molecules that target NF-κB signaling cascade have gained prominent clinical interest. Herein we synthesized a novel class of 4-(substituted)-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one by reacting 2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one with various alkyl halides by using combustion derived bismuth oxide. We evaluated the antiproliferative efficacy of newly synthesized compounds against HCC cells and identified 4-(4-nitrobenzyl)-2H-pyrido[3,2-b][1,4]oxazin-3(4H)-one (NPO) as lead anticancer agent. In addition, we investigated the effect of NPO on the DNA binding ability of NF-κB and NF-κB regulated luciferase expression in HCC cells. The results demonstrated that NPO can induce significant growth inhibitory effects in HepG2, HCCLM3 and Huh-7 cells in dose and time-dependent manner. Interestingly, NPO induced significant downregulation in p65 DNA binding ability, p65 phosphorylation and subsequent expression of NF-κB dependent luciferase gene expression in diverse HCC cell lines. Further, in silico docking analysis suggested that NPO can show direct physical interaction with NF-κB. Finally, NPO was found to significantly abrogate tumor growth at a dose of 50 mg/kg in an orthotopic mouse model. Thus, we report the potential anticancer effects of NPO as a novel inhibitor of NF-κB signaling pathway in HCC.

Garcinol exerts anti-cancer effect in human cervical cancer cells through upregulation of T-cadherin

Garcinol, a polyisoprenylated benzophenone, has been demonstrated to exert anti-cancer effects in various tumor cells. However, the effect of garcinol on cervical cancer (CC) cell progression and the related molecular mechanism remains poorly understood. Accumulating evidence has verified that downregualtion of T-cadherin is closely associated with tumorigenesis, suggesting that T-cadherin might be a potential therapeutic target for cancer treatment. In the present study, Hela and SiHa cells were treated with different concentrations of garcinol (0, 5, 10, and 25 u M), and T-cadherin siRNA was synthesized and transfected into Hela and SiHa cells combined with garcinol (25 u M) treatment. We found that garcinol dose-dependently suppressed cell viability, colony formation, invasion, migration, cell cycle progression, and promoted cell apoptosis in CC cell lines, as well as inhibited tumor growth in xenograft model. Importantly, our results showed that garcinol treatment increased the expression of T-cadherin both in vitro and in vivo, and knockdown of T-cahderin partially reversed garcinol-induced inhibition of CC development via activating P13 K/AKT signaling pathway in CC cell lines. Thus, these findings demonstrated the tumor suppressive function of garcinol on CC progression, and emphasized that the T-cadherin/P13 K/AKT was a potential mechanism involved in the antumor effects of garcinol.

Magnolol: A Neolignan from the Magnolia Family for the Prevention and Treatment of Cancer

The past few decades have witnessed widespread research to challenge carcinogenesis; however, it remains one of the most important health concerns with the worst prognosis and diagnosis. Increasing lines of evidence clearly show that the rate of cancer incidence will increase in future and will create global havoc, designating it as an epidemic. Conventional chemotherapeutics and treatment with synthetic disciplines are often associated with adverse side effects and development of chemoresistance. Thus, discovering novel economic and patient friendly drugs that are safe and efficacious is warranted. Several natural compounds have proved their potential against this dreadful disease so far. Magnolol is a hydroxylated biphenyl isolated from the root and stem bark of Magnolia tree. Magnolol can efficiently prevent or inhibit the growth of various cancers originating from different organs such as brain, breast, cervical, colon, liver, lung, prostate, skin, etc. Considering these perspectives, the current review primarily focuses on the fascinating role of magnolol against various types of cancers, and the source and chemistry of magnolol and the molecular mechanism underlying the targets of magnolol are discussed. This review proposes magnolol as a suitable candidate that can be appropriately designed and established into a potent anti-cancer drug.

Evidence for the Involvement of the Master Transcription Factor NF-κB in Cancer Initiation and Progression

Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is responsible for the regulation of a large number of genes that are involved in important physiological processes, including survival, inflammation, and immune responses. At the same time, this transcription factor can control the expression of a plethora of genes that promote tumor cell proliferation, survival, metastasis, inflammation, invasion, and angiogenesis. The aberrant activation of this transcription factor has been observed in several types of cancer and is known to contribute to aggressive tumor growth and resistance to therapeutic treatment. Although NF-κB has been identified to be a major contributor to cancer initiation and development, there is evidence revealing its role in tumor suppression. This review briefly highlights the major mechanisms of NF-κB activation, the role of NF-κB in tumor promotion and suppression, as well as a few important pharmacological strategies that have been developed to modulate NF-κB function.

Garcinol Enhances TRAIL-Induced Apoptotic Cell Death through Up-Regulation of DR5 and Down-Regulation of c-FLIP Expression

Garcinol is a polyisoprenylated benzophenone derived from the Garcinia indica fruit that possess potential therapeutic effects such as inhibition of inflammation and tumor expansion. Here, we investigated whether garcinol induces TRAIL sensitization in renal carcinoma cells. Single treatment with garcinol or TRAIL did not effect on apoptosis. However, combined treatment with garcinol plus TRAIL significantly induced apoptosis in renal carcinoma (Caki, ACHN and A498), lung carcinoma (A549), and hepatoma (SK-Hep1) cells. In contrast, garcinol plus TRAIL did not alter cell viability in normal cells. Garcinol plus TRAIL induced up-regulation of DR5 and down-regulation of c-FLIP expression at post-translational levels. Furthermore, knock-down of DR5 by siRNA and ectopic expression of c-FLIP blocked apoptotic cell death induced by garcinol plus TRAIL. Overall, our study provides evidence that garcinol can be exploited as a potential TRAIL sensitizer.

Safety profile of 40% Garcinol from Garcinia indica in experimental rodents

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Evaluated standardized 40% Garcinol in Wistar rats for its safety.

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Acute, sub-acute sub-chronic and reproductive/developmental toxicity study conducted.

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40% Garcinol safe up to 2000 mg/kg at single dose.

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NOAEL of 40% Garcinol at sub acute, sub-chronic and reproductive/developmental study is 100 mg/kg/day.

The present study was taken up to evaluate the single dose acute toxicity, 28 days and 90 days repeated dose toxicity and reproductive/developmental toxicity of standardized 40% Garcinol in experimental rodents. The studies were conducted in compliance with OECD principles of good laboratory practice, guidelines for testing of chemicals no.420, 407, 408 and 421 respectively. Single dose acute oral toxicity was conducted on female Wistar rats as sighting study step-I (300 mg/kg) & sighting study step-II (2000 mg/kg) and main study (2000 mg/kg). Sub-acute, sub-chronic and reproductive/developmental studies were conducted in Wistar rats divided equally in vehicle control, 20, 50 and 100 mg/kg dose group along with recovery groups for vehicle control and high dose. Reproductive/developmental study was carried out for minimum of 28 days and in females during pregnancy and 4 days post partum. There were no abnormal clinical signs/behavioural changes, reproductive and developmental parameters, gross and histopathological changes as well as no alteration in the body weight, body temperature, haematology and other biochemical parameters in all the four studies. 40% Garcinol has a low toxicity profile in rodents and had no observed effects under experimental conditions used.

Natural compound Oblongifolin C confers gemcitabine resistance in pancreatic cancer by downregulating Src/MAPK/ERK pathways

Gemcitabine (GEM)-induced drug resistance is the major reason for the failure of chemotherapy in pancreatic cancer (PC). In this study, we found that Oblongifolin C (OC) efficiently inhibited PC cell proliferation by inducing G0/G1 arrest and apoptosis. Also, our mechanism study demonstrated that OC re-sensitized the GEM-resistant PC cells through the ubiquitin-proteasome-dependent degradation of Src, and then downregulating the MAPK pathway. Knockdown of Src plus OC resulted in a greater inhibitory effect in GEM-resistant PC cells. In contrast, Src overexpression reversed OC-mediated chemosensitization, thereby implicating Src in the action of OC. Moreover, our in vivo study showed that OC suppressed the tumor growth via the downregulation of Src, and enhanced the chemosensitivity of GEM-resistant PC to GEM. Overall, our results have revealed that OC is applicable as a promising agent for overcoming GEM-resistant PC, especially with aberrant Src expression.

Research Progress of Polycyclic Polyprenylated Acylphloroglucinols

Polycyclic polyprenylated acylphloroglucinols (PPAPs) are a class of hybrid natural products sharing the mevalonate/methylerythritol phosphate and polyketide biosynthetic pathways and showing considerable structure and bioactivity diversity. This review discusses the progress of research into the chemistry and biological activity of 421 natural PPAPs in the past 11 years as well as in-depth studies of biological activities and total synthesis of some PPAPs isolated before 2006. We created an online database of all PPAPs known to date at http://www.chem.uky.edu/research/grossman/PPAPs . Two subclasses of biosynthetically related metabolites, spirocyclic PPAPs with octahydrospiro[cyclohexan-1,5'-indene]-2,4,6-trione core and complicated PPAPs produced by intramolecular [4 + 2] cycloadditions of MPAPs, are brought into the PPAP family. Some PPAPs' relative or absolute configurations are reassigned or critically discussed, and the confusing trivial names in PPAPs investigations are clarified. Pharmacologic studies have revealed a new molecular mechanism whereby hyperforin and its derivatives regulate neurotransmitter levels by activating TRPC6 as well as the antitumor mechanism of garcinol and its analogues. The antineoplastic potential of some type B PPAPs such as oblongifolin C and guttiferone K has increased significantly. As a result of the recent appearances of innovative synthetic methods and strategies, the total syntheses of 22 natural PPAPs including hyperforin, garcinol, and plukenetione A have been accomplished.

TR4 nuclear receptor enhances the cisplatin chemo-sensitivity via altering the ATF3 expression to better suppress HCC cell growth

Early studies indicated that TR4 nuclear receptor (TR4) may play a key role to modulate the prostate cancer progression, its potential linkage to liver cancer progression, however, remains unclear. Here we found that higher TR4 expression in hepatocellular carcinoma (HCC) cells might enhance the efficacy of cisplatin chemotherapy to better suppress the HCC progression. Knocking down TR4 with TR4-siRNA in HCC Huh7 and Hep3B cells increased cisplatin chemotherapy resistance and overexpression of TR4 with TR4-cDNA in HCC LM3 and SNU387 cells increased cisplatin chemotherapy sensitivity. Mechanism dissection found that TR4 might function through altering the ATF3 expression at the transcriptional level to enhance the cisplatin chemotherapy sensitivity, and interrupting ATF3 expression via ATF3-siRNA reversed TR4-enhanced cisplatin chemotherapy sensitivity in HCC cells. The in vivo HCC mouse model using xenografted HCC LM3 cells also confirmed in vitro cell lines data showing TR4 enhanced the cisplatin chemotherapy sensitivity. Together, these results provided a new potential therapeutic approach via altering the TR4-ATF3 signals to increase the efficacy of cisplatin to better suppress the HCC progression.

Garcinol and Its Role in Chronic Diseases

The various bioactive compounds isolated from leaves and fruits of Garcinia sps plants, have been characterized and experimentally demonstrated to be anti-oxidant, anti-inflammatory and anti-cancer in nature. Garcinol, a polyisoprenylated benzophenone, obtained from plant Garcinia indica has been found to be an effective inhibitor of several key regulatory pathways (e.g., NF-kB, STAT3 etc.) in cancer cells, thereby being able to control malignant growth of solid tumours in vivo. Despite its high potential as an anti-neoplastic modulator of several cancer types such as head and neck cancer, breast cancer, hepatocellular carcinoma, prostate cancer, colon cancer etc., it is still in preclinical stage due to lack of systematic and conclusive evaluation of pharmacological parameters. While it is promising anti-cancer effects are being positively ascertained for therapeutic development, studies on its effectiveness in ameliorating other chronic diseases such as cardiovascular diseases, diabetes, allergy, neurodegenerative diseases etc., though seem favourable, are very recent and require in depth scientific investigation.

Garcinol from Garcinia indica Downregulates Cancer Stem-like Cell Biomarker ALDH1A1 in Nonsmall Cell Lung Cancer A549 Cells through DDIT3 Activation

Nonsmall cell lung cancer (NSCLC) is the predominant type of lung cancer. Patients with NSCLC show high mortality rates because of failure to clean up cancer stem cells (CSCs). The anticancer activity of phytochemical garcinol has been identified in various cancer cell models. However, the effect of garcinol on NSCLC cell lines is still lacking. Of the NSCLC cell lines we tested, A549 cells were the most sensitive to garcinol. Interestingly, Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1) was preferentially expressed in A549 cells and downregulated by the addition of garcinol. We also found that garcinol enriched DNA damage-inducible transcript 3 (DDIT3) and then altered DDIT3-CCAAT-enhancer-binding proteins beta (C/EBPβ) interaction resulting in a decreased binding of C/EBPβ to the endogenous ALDH1A1 promoter. Furthermore, garcinol's inhibition of ALDH1A1 was identified in a xenograft mice model. Garcinol repressed ALDH1A1 transcription in A549 cells through alterations in the interaction between DDIT3 and C/EBPβ. Garcinol could be a potential dietary phytochemical candidate for NSCLCs patients whose tumors harbored high ALDH1A1 expression.

The C8 side chain is one of the key functional group of Garcinol for its anti-cancer effects

Garcinol from the fruit rind of Garcinia indica shows anti-carcinogenic and anti-inflammatory properties, but its mechanism and key functional groups were still need to be identified. Our previous computer modeling suggested that the C8 side chain of Garcinol is so large that it may influence the bioactivity of the compound. 8-Me Garcinol, a derivative of Garcinol in which the bulky side chain at the C8 position of Garcinol is replaced with a much smaller methyl group, was synthesized through a 12-step procedure starting from 1,3-cyclohexanedione. The antitumor activity of Garcinol and 8-Me Garcinol was evaluated in vitro by MTT, cell cycle and cell apoptosis assays. The results showed that 8-Me Garcinol had weaker inhibitory activity on cells proliferation, and little effects on cell cycle and apoptosis in oral cancer cell line SCC15 cells when compared with Garcinol. All of the results indicated 8-Me Garcinol exerts weaker antitumor activity than Garcinol, and the C8 side chain might be an important active site in Garcinol. Changing the C8 side chain will affect the inhibitory effect of Garcinol.

Garcinol exhibits anti-proliferative activities by targeting microsomal prostaglandin E synthase-1 in human colon cancer cells

BACKGROUND

Colorectal cancer is the fourth leading cause of death. Various natural compounds are known to have antitumor properties. Garcinol, a polyisoprenylated benzophenone, has antioxidant and anti-inflammatory properties. In the current study, we investigated the anticancer activity of garcinol on human colorectal adenocarcinoma cell line (HT-29) human colon cancer cells.

METHODS

HT-29 cells were treated with various concentrations of garcinol for 24 h. The effect of garcinol on HT-29 cells proliferation was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay; the mRNA expression of microsomal prostaglandin E synthase-1 (mPGES-1), hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), C-X-C chemokine receptor type 4 (CXCR4), matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9) were examined by quantitative real-time polymerase chain reaction; apoptosis was detected by proportion of sub-G1 cell; caspase 3 activity and prostaglandin E2 (PGE2) level were determined by enzyme-linked immunosorbent assay and HT-29 cells migration was assessed using scratch test.

RESULTS

Garcinol preconditioning markedly decreased the expression of mPGES-1, HIF-1α, VEGF, CXCR4, MMP-2, and MMP-9. The proportion of cells in sub-G1 phase and caspase 3 activity were increased by garcinol treatment whereas the cell proliferation, PGE2 level, and cell migration were decreased in these cells, compared to the control group.

CONCLUSION

Our findings suggest that garcinol plays a critical role in elevating apoptosis and inhibiting HT-29 cells proliferation, angiogenesis, and invasion by suppressing the mPGES-1/PGE2/HIF-1α signaling pathways.

Aberrant lysine acetylation in tumorigenesis: Implications in the development of therapeutics

The 'language' of covalent histone modifications translates environmental and cellular cues into gene expression. This vast array of post-translational modifications on histones are more than just covalent moieties added onto a protein, as they also form a platform on which crucial cellular signals are relayed. The reversible lysine acetylation has emerged as an important post-translational modification of both histone and non-histone proteins, dictating numerous epigenetic programs within a cell. Thus, understanding the complex biology of lysine acetylation and its regulators is essential for the development of epigenetic therapeutics. In this review, we will attempt to address the complexities of lysine acetylation in the context of tumorigenesis, their role in cancer progression and emphasize on the modalities developed to target lysine acetyltransferases towards cancer treatment.

Adamantyl-tethered-biphenylic compounds induce apoptosis in cancer cells by targeting Bcl homologs

Bcl homologs prominently contribute to apoptotic resistance in cancer cells and serve as molecular targets in treatment of various cancers. Herein, we report the synthesis of biphenyl-adamantane derivatives by a ligand free palladium on carbon based Suzuki reaction using diisopropylamine as a base for the coupling of adamantane based aryl chloride with a variety of aryl boronic acids. Among the biphenyl derivatives synthesized, compound 3'-(adamantan-1-yl)-4'-methoxy-[1,1'-biphenyl]-3-ol (AMB) displayed cytotoxic activity against hepatocellular carcinoma cell lines without significantly affecting the normal cell lines. Further, AMB caused increased accumulation of the HCC cells in subG1 phase, decreased the expression of Bcl-2, Bcl-xL, cyclin D1, caspase-3, survivin and increased the cleavage of PARP in a time-dependent manner. In silico molecular interaction studies between Bcl homologs and AMB showed that the biphenyl scaffold is predicted to form π-π interactions with Phe-101 and Tyr-105 and the adamantyl fragment is predicted to occupy another hydrophobic region in the kink region of the binding groove. In summary, we report on the synthesis and biological characterization of adamantyl-tethered biphenylic compounds that induce apoptosis in tumor cells most likely by targeting Bcl homologs.

Association of CCND1 gene polymorphism with cervical cancer susceptibility in Caucasian population: a meta-analysis

OBJECTIVE

To study G870A polymorphism in CCND1 gene and the risk of cervical cancer susceptibility in Caucasian population by meta-analysis.

METHODS

Search the correlative study of G870A polymorphism in CCND1 gene and cervical cancer susceptibility in PubMed and EMBASE database, and extract the reference data according to the including criteria. We used RevMan 5.2 software to merge the OR value and 95% confidence interval and to perform meta-analysis.

RESULTS

Five case-control studies were enrolled into the analysis, including 1665 patients with cervical cancer and 2511 healthy people as control. It was revealed by meta-analysis that, in the Caucasian population, there was no significant correlation between G870A polymorphism in CCND1 gene and the risk of cervical cancer (G allele vs. A: OR = 1.01, 95% CI = 0.80-1.27, P = 0.95; AA vs. GA + GG: OR = 1.13, 95% CI = 0.98-1.30, P = 0.10; (GA + AA) vs. GG: OR = 1.15, 95% CI = 0.72-1.85, P = 0.55).

CONCLUSION

G870A polymorphism in CCND1 gene may be uncorrelated with the development of cervical cancer in Caucasian population.