Inhibition of cell proliferation by a resveratrol analog in human pancreatic and breast cancer cells

A Concise Review on Natural Products and Their Derivatives for Breast Cancer Treatment

Cancer is a leading cause of death worldwide. Among other cancers, breast cancer has been found to produce maximum number of cases in 2020. Different factors including geographical, genetic, hormonal, oral contraceptives and modern lifestyle could be responsible for the development of breast cancer and different pathways can be targeted for breast cancer treatment. The various conventional approaches used for the treatment of breast cancer including radiotherapy, chemotherapy, hormone and immunotherapy. But due to the side effects associated with these conventional treatments such as non-selectivity, multidrug resistance and bioavailability, there is a need for the development of better therapeutic agents for breast cancer treatment. Several natural products have been explored for breast cancer treatment. However, many of these natural products suffered from the limitations of poor water solubility and possess toxic side effects. To overcome these limitations, several structural analogs of natural products have been synthesized and possess potent anti-breast cancer effects with less side effects over their precursor molecules. In the present manuscript, we describe the pathogenesis of breast cancer, some potent natural products used in the treatment of breast cancer and their selected structural analogs possessing potent anti-breast cancer effects. Database such as Science direct, Pubmed and Google scholar were searched using keywords 'risk factors', 'screening methods','receptors', and 'natural products and derivatives', Registered clinical trials on selected natural products were also analyzed. Present study concludes that eight selected natural products and their derivatives possess wide potential to exhibit anti-breast cancer effects and could be explored further to develop better chemotherapeutic agents against breast cancer.

Applications of resveratrol in the treatment of gastrointestinal cancer

Natural product compounds have lately attracted interest in the scientific community as a possible treatment for gastrointestinal (GI) cancer, due to their anti-inflammatory and anticancer properties. There are many preclinical, clinical, and epidemiological studies, suggesting that the consumption of polyphenol compounds, which are abundant in vegetables, grains, fruits, and pulses, may help to prevent various illnesses and disorders from developing, including several GI cancers. The development of GI malignancies follows a well-known path, in which normal gastrointestinal cells acquire abnormalities in their genetic composition, causing the cells to continuously proliferate, and metastasize to other sites, especially the brain and liver. Natural compounds with the ability to affect oncogenic pathways might be possible treatments for GI malignancies, and could easily be tested in clinical trials. Resveratrol is a non-flavonoid polyphenol and a natural stilbene, acting as a phytoestrogen with anti-cancer, cardioprotective, anti-oxidant, and anti-inflammatory properties. Resveratrol has been shown to overcome resistance mechanisms in cancer cells, and when combined with conventional anticancer drugs, could sensitize cancer cells to chemotherapy. Several new resveratrol analogs and nanostructured delivery vehicles with improved anti-GI cancer efficacy, absorption, and pharmacokinetic profiles have already been developed. This present review focuses on the in vitro and in vivo effects of resveratrol on GI cancers, as well as the underlying molecular mechanisms of action.

The role of Wnt/mTOR signaling in spinal cord injury

Spinal cord injury (SCI) is the most common disabling spinal injury, a complex pathologic process that can eventually lead to severe neurological dysfunction. The Wnt/mTOR signaling pathway is a pervasive signaling cascade that regulates a wide range of physiological processes during embryonic development, from stem cell pluripotency to cell fate. Numerous studies have reported that Wnt/mTOR signaling pathway plays an important role in neural development, synaptogenesis, neuron growth, differentiation and survival after the central nervous system (CNS) is damaged. Wnt/mTOR also plays an important role in regulating various pathophysiological processes after spinal cord injury (SCI). After SCI, Wnt/mTOR signal regulates the physiological and pathological processes of neural stem cell proliferation and differentiation, neuronal axon regeneration, neuroinflammation and pain through multiple pathways. Due to the characteristics of the Wnt signal in SCI make it a potential therapeutic target of SCI. In this paper, the characteristics of Wnt/mTOR signal, the role of Wnt/mTOR pathway on SCI and related mechanisms are reviewed, and some unsolved problems are discussed. It is hoped to provide reference value for the research field of the role of Wnt/mTOR pathway in SCI, and provide a theoretical basis for biological therapy of SCI.

mTOR pathway: A potential therapeutic target for spinal cord injury

Spinal cord injury (SCI) is the most common disabling spinal injury, and the complex pathological process can eventually lead to severe neurological dysfunction. Many studies have reported that the mammalian target of rapamycin (mTOR) signaling pathway plays an important role in synaptogenesis, neuron growth, differentiation, and survival after central nervous system injury. It is also involved in various traumatic and central nervous system diseases, including traumatic brain injury, neonatal hypoxic-ischemic brain injury, Alzheimer's disease, Parkinson's disease, and cerebral apoplexy. mTOR has also been reported to play an important regulatory role in various pathophysiological processes following SCI. Activation of mTOR signals after SCI can regulate physiological and pathological processes, such as proliferation and differentiation of neural stem cells, regeneration of nerve axons, neuroinflammation, and glial scar formation, through various pathways. Inhibition of mTOR activity has been confirmed to promote repair in SCI. At present, many studies have reported that Chinese herbal medicine can inhibit the SCI-activated mTOR pathway to improve the microenvironment and promote nerve repair after SCI. Due to the role of the mTOR pathway in SCI, it may be a potential therapeutic target for SCI. This review is focused on the pathophysiological process of SCI, characteristics of the mTOR pathway, role of the mTOR pathway in SCI, role of inhibition of mTOR on SCI, and role and significance of inhibition of mTOR by related Chinese herbal medicine inhibitors in SCI. In addition, the review discusses the deficiencies and solutions to mTOR and SCI research shortcomings. This study hopes to provide reference for mTOR and SCI research and a theoretical basis for SCI biotherapy.

Doxycycline potentiates the anti-proliferation effects of gemcitabine in pancreatic cancer cells

Gemcitabine is often recommended as a first-line treatment for patients with metastatic pancreatic cancer. However, gemcitabine resistance is a major challenge in the treatment of pancreatic ductal adenocarcinoma. Our group serendipitously identified the role of doxycycline as a potentiator of gemcitabine efficacy in pancreatic cancer cells. Doxycycline and gemcitabine co-treatment was significantly more cytotoxic to pancreatic cancer cells compared to gemcitabine alone. Interestingly, doxycycline only exerted synergistic effects when coupled with gemcitabine as opposed to other conventional chemotherapeutics including nucleoside analogs. The anti-clonogenic effects of gemcitabine on pancreatic cancer cells were also enhanced by doxycycline. According to cell cycle analyses, doxycycline prolonged gemcitabine-mediated S phase cell cycle arrest. Further, gene expression profiling analyses indicated that a small set of genes involved in cell cycle regulation were uniquely modulated by gemcitabine and doxycycline co-treatment compared to gemcitabine alone. Western blot analyses indicated that several cell cycle-related proteins, including cyclin D1, p21, and DNA damage inducible transcript 4 (DDIT4), were further modulated by doxycycline and gemcitabine co-treatment. Taken together, our findings indicate that doxycycline enhances the effects of gemcitabine on cell cycle progression, thus rendering pancreatic cancer cells more sensitive to gemcitabine. However, additional studies are required to assess the mechanisms of doxycycline and gemcitabine synergism, which might lead to novel treatment options for pancreatic cancer.

Combinatorial Epigenetics Impact of Polyphenols and Phytochemicals in Cancer Prevention and Therapy

Polyphenols are potent micronutrients that can be found in large quantities in various food sources and spices. These compounds, also known as phenolics due to their phenolic structure, play a vital nutrient-based role in the prevention of various diseases such as diabetes, cardiovascular diseases, neurodegenerative diseases, liver disease, and cancers. However, the function of polyphenols in disease prevention and therapy depends on their dietary consumption and biological properties. According to American Cancer Society statistics, there will be an expected rise of 23.6 million new cancer cases by 2030. Due to the severity of the increased risk, it is important to evaluate various preventive measures associated with cancer. Relatively recently, numerous studies have indicated that various dietary polyphenols and phytochemicals possess properties of modifying epigenetic mechanisms that modulate gene expression resulting in regulation of cancer. These polyphenols and phytochemicals, when administrated in a dose-dependent and combinatorial-based manner, can have an enhanced effect on epigenetic changes, which play a crucial role in cancer prevention and therapy. Hence, this review will focus on the mechanisms of combined polyphenols and phytochemicals that can impact various epigenetic modifications such as DNA methylation and histone modifications as well as regulation of non-coding miRNAs expression for treatment and prevention of various types of cancer.

Resveratrol and other dietary polyphenols are inhibitors of estrogen metabolism in human breast cancer cells

Polyphenols in foods and dietary supplements are commonly used for the prevention and treatment of a variety of malignancies, including breast cancer. However, daily intake by patients with breast cancer is controversial, as these compounds may stimulate cancer growth. Estrogens serve key roles in breast cancer cell proliferation; therefore, understanding the interaction between endogenous steroid hormones and natural dietary polyphenols is essential. Currently, comprehensive knowledge regarding these effects remains limited. The current review summarizes the dose-dependent in vitro and in vivo interactions of resveratrol and other dietary polyphenols with estrogen precursors, active estrogens, catechol estrogens and their respective glucuronidated, sulfated, glutathionated or O-methylated metabolites in estrogen receptor alpha negative (ERα-) and positive (ERα+) breast cancer. Which estrogen-metabolizing enzymes are affected by polyphenols is also reviewed in detail. Furthermore, the impacts of dose and therapy duration on disease development and progression in patients with breast cancer are discussed. The present article is part of a Special Issue titled 'CSR 2018'.

Combinational Proanthocyanidins and Resveratrol Synergistically Inhibit Human Breast Cancer Cells and Impact Epigenetic⁻Mediating Machinery

Breast cancer is the second most common cancer and the second leading cause of death from cancer among women in the United States (US). Cancer prevention and therapy through the use of phytochemicals that have epigenetic properties has gained considerable interest during the past few decades. Such dietary components include, but are not limited to, grape seed proanthocyanidins (GSPs) and resveratrol (Res), both of which are present in red wine. In this study, we report for the first time the synergistic effects of GSPs and Res on inhibiting MDA-MB-231 and MCF-7 human breast cancer cells. Our results of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and clonogenic assays indicate that treatments with the combinations of GSPs and Res synergistically decreased cell viability and posttreatment cell proliferation in both cell lines. Additional analyses show that treatments with GSPs and Res in combination synergistically induced apoptosis in MDA-MB-231 cells by upregulating Bax expression and down-regulating Bcl-2 expression. DNA methyltransferase (DNMT) activity and histone deacetylase (HDAC) activity were greatly reduced in MDA-MB-231 and MCF-7 cells after treatments with GSPs and Res in combination. Collectively, our findings suggest that GSPs and Res synergistically inhibit human breast cancer cells through inducing apoptosis, as well as modulating DNA methylation and histone modifications.

p27kip1 as a key regulator of endometriosis

p27^kip1 as a key regulator of endometriosis Gonçalves GA p27^kip1 is a cyclin-dependent kinase (CDK) inhibitor whose specific late G1 destruction allows progression of the cell across the G1/S boundary. There is a direct relationship between low level of p27 and rapid proliferation occurring in several benign states and in many malignances. In the glandular cells of the normal endometrium, the level of p27^kip1 is exceedingly low during the proliferative phase, whereas it is markedly increased during the secretory phase. The expression of p27^kip1 in endometriosis is very low but has been found to increase following treatment with progesterone. However, estrogen exposure is considered as a major risk factor in developing endometrial cancer. Endometriosis endometrial cells cultures have also lower levels of p27^kip1 compared to heath endometrial cells cultures and restore the cell cycle balance when transduced with an adenoviral vector carring the p27^kip1 coding gene (Adp27EGFP). More uniform and rigorous studies are required to confirm these and additional markers utility in a diagnostic and possible treatment panel. As a major clinical priority is to determine which lesions can be treated medically and which require surgical intervention, focusing future studies on markers that distinguish response to hormone therapy or are involved in hormone regulation, will be important future considerations. The goal of this highlight review is to provide a broad overview of the advancements in studies about endometriosis mainly correlating the cytokine p27^kip1 expression with the diagnostic and disease treatment.

Resveratrol improves neuron protection and functional recovery through enhancement of autophagy after spinal cord injury in mice

Resveratrol (Res), a natural phenolic compound, has been proven to have a wide variety of beneficial health effects. For example, resveratrol has neuroprotective effects in different central nervous system diseases. However, the mechanisms underlying resveratrol neuroprotection in spinal cord injury (SCI) remain unclear. In this study, we showed that resveratrol treatment improved the restoration of locomotor function, and decreased the degeneration of neurons in SCI mice, which was paralleled by a reduction of apoptosis. We further examined autophagy markers via western blot and immunofluorescence. Results showed that the beneficial effects of resveratrol were related to the promotion LC3II and beclin-1 expression. In addition, autophagy suppression with chloroquine (CQ) partially abolished apoptosis inhibition and locomotor functional improvement of Res on SCI, which indicated that the beneficial effect of resveratrol on SCI was through autophagy enhancement. In conclusion, these results illustrated that the neuroprotective effects of resveratrol in SCI are partially through autophagy stimulation, and implied that Res is a promising drug for SCI therapy.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

Effect of resveratrol on cancer progression through the REG Ⅲ expression pathway in head and neck cancer cells

Identification of reliable markers of chemo- and radiosensitivity and the key molecules that enhance the susceptibility of head and neck squamous cell carcinoma (HNSCC) to anticancer treatments is highly desirable. Previously, we have reported that regenerating gene (REG) Ⅲ expression was such a marker associated with an improved survival rate for HNSCC patients. In the present study, we investigated the stimulators for induction of REG Ⅲ expression using REG Ⅲ promoter assay in HNSCC cells transfected with REG Ⅲ promoter vector. We tested inflammatory cytokines, growth factors, polyphenols, PPARγ activator of thiazolidinediones, and histone deacetylase inhibitors, and found that 3,4',5-trihydroxy-trans-stilbene (resveratrol) significantly increased the REG Ⅲ promoter activity and the mRNA levels of REG Ⅲ in HNSCC cells. Moreover, we demonstrated the effect of resveratrol on cancer cell progression, such as cell proliferation, chemo‑ and radiosensitivity and cancer invasion of HNSCC cells. Resveratrol significantly inhibited cell growth, enhanced chemo‑ and radiosensitivity, and blocked cancer invasion of HNSCC cells. These data suggested that resveratrol could inhibit cancer progression through the REG Ⅲ expression pathway in HNSCC cells.

Resveratrol for breast cancer prevention and therapy: Preclinical evidence and molecular mechanisms

Globally, breast cancer is the most frequently diagnosed cancer among women. The major unresolved problems with metastatic breast cancer is recurrence after receiving objective response to chemotherapy, drug-induced side effects of first line chemotherapy and delayed response to second line of treatment. Unfortunately, very few options are available as third line treatment. It is clear that under such circumstances there is an urgent need for new and effective drugs. Phytochemicals are among the most promising chemopreventive treatment options for the management of cancer. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a non-flavonoid polyphenol present in several dietary sources, including grapes, berries, soy beans, pomegranate and peanuts, has been shown to possess a wide range of health benefits through its effect on a plethora of molecular targets.The present review encompasses the role of resveratrol and its natural/synthetic analogue in the light of their efficacy against tumor cell proliferation, metastasis, epigenetic alterations and for induction of apoptosis as well as sensitization toward chemotherapeutic drugs in various in vitro and in vivo models of breast cancer. The roles of resveratrol as a phytoestrogen, an aromatase inhibitor and in stem cell therapy as well as adjuvent treatment are also discussed. This review explores the full potential of resveratrol in breast cancer prevention and treatment with current limitations, challenges and future directions of research.

The p27 Pathway Modulates the Regulation of Skeletal Growth and Osteoblastic Bone Formation by Parathyroid Hormone-Related Peptide

Parathyroid hormone-related peptide (PTHrP) 1-84 knock-in mice (Pthrp KI) develop skeletal growth retardation and defective osteoblastic bone formation. To further examine the mechanisms underlying this phenotype, microarray analyses of differential gene expression profiles were performed in long bone extracts from Pthrp KI mice and their wild-type (WT) littermates. We found that the expression levels of p27, p16, and p53 were significantly upregulated in Pthrp KI mice relative to WT littermates. To determine whether p27 was involved in the regulation by PTHrP of skeletal growth and development in vivo, we generated compound mutant mice, which were homozygous for both p27 deletion and the Pthrp KI mutation (p27(-/-) Pthrp KI). We then compared p27(-/-) Pthrp KI mice with p27(-/-), Pthrp KI, and WT littermates. Deletion of p27 in Pthrp KI mice resulted in a longer lifespan, increased body weight, and improvement in skeletal growth. At 2 weeks of age, skeletal parameters, including length of long bones, size of epiphyses, numbers of proliferating cell nuclear antigen (PCNA)-positive chondrocytes, bone mineral density, trabecular bone volume, osteoblast numbers, and alkaline phosphatase (ALP)-, type I collagen-, and osteocalcin-positive bone areas were increased in p27(-/-) mice and reduced in both Pthrp KI and p27(-/-) Pthrp KI mice compared with WT mice; however, these parameters were increased in p27(-/-) Pthrp KI mice compared with Pthrp KI mice. As well, protein expression levels of PTHR, IGF-1, and Bmi-1, and the numbers of total colony-forming unit fibroblastic (CFU-f) and ALP-positive CFU-f were similarly increased in p27(-/-) Pthrp KI mice compared with Pthrp KI mice. Our results demonstrate that deletion of p27 in Pthrp KI mice can partially rescue defects in skeletal growth and osteoblastic bone formation by enhancing endochondral bone formation and osteogenesis. These studies, therefore, indicate that the p27 pathway may function downstream in the action of PTHrP to regulate skeletal growth and development.

Resveratrol protects spinal cord dorsal column from hypoxic injury by activating Nrf-2

Damage from oxidative stress plays a critical role in spinal cord injury. Nuclear factor erythroid 2-related factor (Nrf-2) signaling pathway can be activated by cellular oxidative stress. Resveratrol, a plant-derived polyphenolic compound found in red wine, has antioxidant properties. In the present study, we have examined the neuroprotective effect of resveratrol and the role of Nrf-2 in spinal cord hypoxic injury. The spinal cord was removed from adult male Wistar rats from T2-T10 and the dorsal column was used to induce hypoxic injury in vitro with and without treatment with resveratrol (50μM). Significant changes were found in the compound action potential (CAP) of spinal cord dorsal column, and hematoxyline and eosin (H&E) staining showed that resveratrol significantly improved neuronal injury. The biochemical assays showed significant changes in lipid peroxidase (LPO), reduced glutathione (GSH), superoxide dismutase (SOD), protein carbonyl (PC), mitochondrial ATP content, and mitochondrial Ca(++). Furthermore, using immunohistochemistry and Western blot, we found that after resveratrol treatment during hypoxic injury there was a significant activation of NrF-2 and down regulation of the glial fibrillary acidic protein (GFAP) content. The results show that resveratrol treatment has neuroprotective effects on CAP, Ca(++) loading, and biochemical parameters after hypoxic injury. The neuroprotective effect is likely to be exerted by increased activation of transcription factor Nrf-2 by resveratrol along with its direct antioxidant effect to ameliorate the oxidative damage and preserve mitochondrial function.

miR-148b functions as a tumor suppressor in pancreatic cancer by targeting AMPKα1

miRNAs are small noncoding RNAs that participate in a variety of biologic processes, and dysregulation of miRNA is always associated with cancer development and progression. Aberrant expression of miR-148b has been found in some types of cancer, but its expression and potential biologic role in pancreatic cancer are still largely unknown. In this study, our data showed that miR-148b was significantly downregulated in 48 pairs of human pancreatic cancer tissues and five cell lines. Furthermore, the deregulated miR-148b was correlated with increased tumor size, late tumor-node-metastasis stage, lymphatic invasion, distant metastasis, and worse prognosis in pancreatic cancer. Functional studies indicated overexpression of miR-148b dramatically suppressed the growth of cancer cells, attributable to induction of apoptosis and cell-cycle arrest at S-phase. Meanwhile, miR-148b remarkably inhibited invasion and enhanced chemosensitivity of pancreatic cancer cells. Moreover, ectopic expression of miR-148b was able to inhibit tumorigenicity in nude mice. Further studies revealed that AMPKα1 might be the direct target gene of miR-148b, and overexpressed AMPKα1 inversely correlated with miR-148b in pancreatic cancer. Silencing of AMPKα1 with RNA interference inhibited the growth of pancreatic cancer cells in vitro and in vivo and also induced apoptosis, cell-cycle arrest, and inhibited invasion of cancer cells, which is consistent with the effects of miR-148b overexpression. In conclusion, miR-148b can inhibit cell proliferation, invasion, and enhance chemosensitivity of pancreatic cancer by targeting AMPKα1. Our present results implicate the potential effects of miR-148b on prognosis and treatment of pancreatic cancer.

Pancreatic cancer chemoprevention by phytochemicals

Pancreatic cancer is fourth leading cause of cancer-related deaths in the United States of America. In spite of recent advances in the current therapeutic modalities such as surgery, radiation and chemotherapy patients, the average five year survival rate remains still less than 5%. Recently, compounds from natural sources receive ample of attention as anti-cancer agents. Many epidemiological studies published over the past few decades provide a strong correlation between consumption of vegetables, fruits or plant derived products and reduced incidence of cancer. The present review focuses on the potential antitumor effects of various natural products.

Grape-seed procyanidins inhibit the in vitro growth and invasion of pancreatic carcinoma cells

OBJECTIVES

Grape-seed procyanidins (GSPs) can inhibit cell proliferation and invasiveness in various human cancers. However, the effect of GSP on pancreatic carcinoma cells has not been investigated.

METHODS

Pancreatic carcinoma cell lines MIA PaCa-2 and BxPC-3 treated with GSP were assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for increased apoptosis by annexin V labeling, for their adhesion and invasion potential by evaluating their ability to penetrate through a matrix gel-coated Boyden chamber, and for changes in the levels of proteins involved in cellular events by immunoblotting.

RESULTS

Grape-seed procyanidin inhibited MIA PaCa-2 and BxPC-3 proliferation in a dose-dependent manner and induced G1-phase arrest of the cell cycle in BxPC-3 or mitochondria-mediated apoptosis in MIA PaCa-2. Grape-seed procyanidin also inhibited the adhesion and invasion potential of both cell lines in a dose-dependent manner, which are associated with the suppression of metalloproteases matrix metalloproteinase 9 or 2 (MMP-9 or -2) expression.

CONCLUSIONS

Grape-seed procyanidin inhibited the proliferation of pancreatic carcinoma cells by cell cycle blockage or apoptotic induction. The invasiveness was also suppressed by GSP through down-regulation of MMP-2 or MMP-9 in pancreatic carcinoma cells. Grape-seed procyanidin is a potential chemotherapeutic or preventive agent for pancreatic carcinoma.

MiR-196a is upregulated in gastric cancer and promotes cell proliferation by downregulating p27(kip1)

Aberrant expression of miR-196a has been frequently reported in cancer studies. However, the expression and mechanism of its function in gastric cancer remains unclear. Quantitative real-time PCR was carried out to detect the relative expression of miR-196a in gastric cancer cell lines and tissues. SGC7901 cells were treated with miR-196a inhibitors, mimics, or pCDNA/miR-196a to investigate the role of miR-196a in cell proliferation. Higher expression of miR-196a in gastric cancer tissues was associated with tumor size, a higher clinical stage, and was also correlated with shorter overall survival of patients with gastric cancer. Exogenous downregulation of miR-196a expression significantly suppressed the in vitro cell-cycle progression, proliferation, and colony formation of gastric cancer cells, and ectopic miR-196a expression significantly enhanced the development of tumors in nude mice. Luciferase assays revealed that miR-196a inhibited p27(kip1) expression by targeting one binding site in the 3'-untranslated region (3'-UTR) of p27(kip1) mRNA. qPCR and Western blot assays verified that miR-196a reduced p27(kip1) expression at both mRNA and protein levels. The p27(kip1)-mediated repression in cell proliferation was reverted by exogenous miR-196a expression. A reverse correlation between miR-196a and p27(kip1) expression was noted in gastric cancer tissues. Our study shows that aberrant overexpression of miR-196a and consequent downregulation of p27(kip1) could contribute to gastric carcinogenesis and would be targets for gastric cancer therapies and further developed as potential prognostic factors.

Resveratrol improves neuron protection and functional recovery in rat model of spinal cord injury

Researches on the pathology of spinal cord injury (SCI) have been recently focused on oxidative radicals stress and inflammation associated neuronal apoptosis. Resveratrol, a natural phenolic compound, has been extensively studied and shown a wide variety of health beneficial effects, including prevention of cardiovascular diseases and cancer and neuroprotective activities. However, the study of its potential role in neuroprotection and underlying mechanism in SCI model has been limited. In this study, we investigated the effect of resveratrol on neurologic functions and histopathologic changes after SCI and the mechanism underlying its neuroprotective effects. First, neuronal function after SCI was evaluated with Basso Beattle Bresnahan locomotor rating scale (BBB) and the result showed that injured animals treated with resveratrol showed a significant increase in BBB scores. Further, histopathological alternations were evaluated with HE and Nissl staining, showing a restored neural morphology and an increase of the number of neurons after resveratrol administration. To explore the underlying mechanism, anti-oxidation effect of resveratrol was assessed by measuring superoxide dismutase (SOD) activity and malondialdehyde (MDA) level after SCI. Resveratrol treatment reversed the decrease of SOD activity and increase of MDA level caused by SCI, suggesting its anti-oxidation role in response to the injury. In addition, resveratrol treatment suppressed immunoreactivity and expression of inflammatory cytokines including IL-1β, IL-10, TNF-α, and myeloperoxidase (MPO) after SCI, suggesting an anti-inflammation effect of resveratrol. Finally, resveratrol treatment inhibited injury-induced apoptosis as assessed by electrical microscopy and TUNEL staining and affected the expression level of apoptosis-related gene Bax, Bcl-2 and caspase-3, which indicated its anti-apoptosis role after SCI. Our data suggest that resveratrol significantly promotes the recovery of rat dorsal neuronal function after SCI, and this effect is related to its characteristics of anti-oxidation, anti-inflammation and anti-apoptosis.

Resveratrol, a red wine polyphenol, suppresses pancreatic cancer by inhibiting leukotriene A₄hydrolase

The anticancer effects of red wine have attracted considerable attention. Resveratrol (3,5,4'-trihydroxy-trans -stilbene) is a well-known polyphenolic compound of red wine with cancer chemopreventive activity. However, the basis for this activity is unclear. We studied leukotriene A(4) hydrolase (LTA(4)H) as a relevant target in pancreatic cancer. LTA(4)H knockdown limited the formation of leukotriene B(4) (LTB(4)), the enzymatic product of LTA(4)H, and suppressed anchorage-independent growth of pancreatic cancer cells. An in silico shape similarity algorithm predicted that LTA(4)H might be a potential target of resveratrol. In support of this idea, we found that resveratrol directly bound to LTA(4)H in vitro and in cells and suppressed proliferation and anchorage-independent growth of pancreatic cancer by inhibiting LTB(4) production and expression of the LTB(4) receptor 1 (BLT(1)). Notably, resveratrol exerted relatively stronger inhibitory effects than bestatin, an established inhibitor of LTA(4)H activity, and the inhibitory effects of resveratrol were reduced in cells where LTA(4)H was suppressed by shRNA-mediated knockdown. Importantly, resveratrol inhibited tumor formation in a xenograft mouse model of human pancreatic cancer by inhibiting LTA(4)H activity. Our findings identify LTA(4)H as a functionally important target for mediating the anticancer properties of resveratrol.

The function of p27 KIP1 during tumor development

Timely cell cycle regulation is conducted by sequential activation of a family of serine-threonine kinases called cycle dependent kinases (CDKs). Tight CDK regulation involves cyclin dependent kinase inhibitors (CKIs) which ensure the correct timing of CDK activation in different phases of the cell cycle. One CKI of importance is p27(KIP1). The regulation and cellular localization of p27(KIP1) can result in biologically contradicting roles when found in the nucleus or cytoplasm of both normal and tumor cells. The p27(KIP1) protein is mainly regulated by proteasomal degradation and its downregulation is often correlated with poor prognosis in several types of human cancers. The protein can also be functionally inactivated by cytoplasmic localization or by phosphorylation. The p27(KIP1) protein is an unconventional tumor suppressor because mutation of its gene is extremely rare in tumors, implying the normal function of the protein is deranged during tumor development. While the tumor suppressor function is mediated by p27(KIP1)s inhibitory interactions with the cyclin/CDK complexes, its oncogenic function is cyclin/CDK independent, and in many cases correlates with cytoplasmic localization. Here we review the basic features and novel aspects of the p27(KIP1) protein, which displays genetically separable tumor suppressing and oncogenic functions.