Pterostilbene prevents AKT-ERK axis-mediated polymerization of surface fibronectin on suspended lung cancer cells independently of apoptosis and suppresses metastasis

Pterostilbene suppresses gastric cancer proliferation and metastasis by inhibiting oncogenic JAK2/STAT3 signaling: In vitro and in vivo therapeutic intervention

BACKGROUND

Gastric cancer (GC) represents a significant health burden with dire prognostic implications upon metastasis and recurrence. Pterostilbene (PTE) has been proven to have a strong ability to inhibit proliferation and metastasis in other cancers, while whether PTE exhibits anti-GC activity and its potential mechanism remain unclear.

PURPOSE

To explore the efficacy and potential mechanism of PTE in treating GC.

METHODS

We employed a comprehensive set of assays, including CCK-8, EdU staining, colony formation, flow cytometry, cell migration, and invasion assays, to detect the effect of PTE on the biological function of GC cells in vitro. The xenograft tumor model was established to evaluate the in vivo anti-GC activity of PTE. Network pharmacology was employed to predict PTE's potential targets and pathways within GC. Subsequently, Western blotting, immunofluorescence, and immunohistochemistry were utilized to analyze protein levels related to the cell cycle, EMT, and the JAK2/STAT3 pathway.

RESULTS

Our study demonstrated strong inhibitory effects of PTE on GC cells both in vitro and in vivo. In vitro, PTE significantly induced cell cycle arrest at G0/G1 and S phases and suppressed proliferation, migration, and invasion of GC cells. In vivo, PTE led to a dose-dependent reduction in tumor volume and weight. Importantly, PTE exhibited notable safety, leaving mouse weight, liver function, and kidney function unaffected. The involvement of the JAK2/STAT3 pathway in PTE's anti-GC effect was predicted utilizing network pharmacology. PTE suppressed JAK2 kinase activity by binding to the JH1 kinase structural domain and inhibited the downstream STAT3 signaling pathway. Western blotting confirmed PTE's inhibition of the JAK2/STAT3 pathway and EMT-associated protein levels. The anti-GC effect was partially reversed upon STAT3 activation, validating the pivotal role of the JAK2/STAT3 signaling pathway in PTE's activity.

CONCLUSION

Our investigation validates the potent inhibitory effects of PTE on the proliferation and metastasis of GC cells. Importantly, we present novel evidence implicating the JAK2/STAT3 pathway as the key mechanism through which PTE exerts its anti-GC activity. These findings not only establish the basis for considering PTE as a promising lead compound for GC therapeutics but also contribute significantly to our comprehension of the intricate molecular mechanisms underlying its exceptional anti-cancer properties.

Pterostilbene upregulates MICA/B via the PI3K/AKT signaling pathway to enhance the capability of natural killer cells to kill cervical cancer cells

Natural killer (NK) cells are triggered by the innate immune response in the tumor microenvironment. The extensive set of stimulating and inhibiting receptors mediates the target recognition of NK cells, and controls the strength of the effector reaction countering specific targeted cells. Yet, lacking major MHC (histocompatibility complex) MICA/B class I chain-related proteins on the membrane of tumor cells results in the failure of NK cell recognition and ability to resist NK cell destruction. Searching databases and molecular docking suggested that in cervical cancer, pterostilbene (3,5-dimethoxy-40-hydroxystilbene; PTS) in Vaccinium corymbosum extract could constrain PI3K/AKT signaling and improving the MICA/B expression. In flow cytometry, MTT assay, viability/cytotoxicity assay, and colony development assays, PTS reduced the development of cervical cancer cells and increased apoptosis. The quantitative real-time PCR (qRT-PCR) and a Western blot indicate that PTS controlled the cytolytic action of NK cells in tumor cells via increasing the MICA/B expression, thus modifying the anti-tumor immune response in cervical cancer.

The effectiveness of blood-activating and stasis-transforming traditional Chinese medicines (BAST) in lung cancer progression-a comprehensive review

ETHNOPHARMACOLOGICAL RELEVANCE

Blood-activating and stasis-transforming traditional Chinese medicines (BAST) are a class of herbs that have the effect of dilating blood vessels and dispersing stagnation. Modern pharmaceutical research has demonstrated that they are capable of improving hemodynamics and micro-flow, resist thrombosis and promote blood flow. BAST contain numerous active ingredients, which can theoretically regulate multiple targets at the same time and have a wide range of pharmacological effects in the treatment of diseases including human cancers. Clinically, BAST have minimal side effects and can be used in combination with Western medicine to improve patients' quality of life, lessen adverse effects and minimize the risk of recurrence and metastasis of cancers.

AIM OF THE REVIEW

We aimed to summarize the research progression of BAST on lung cancer in the past five years and present a prospect for the future. Particularly, this review further analyzes the effects and molecular mechanisms that BAST inhibit the invasion and metastasis of lung cancer.

MATERIALS AND METHODS

Relevant studies about BSAT were collected from PubMed and Web of science.

RESULTS

Lung cancer is one of the malignant tumors with the highest mortality rate. Most patients with lung cancer are diagnosed at an advanced stage and are highly susceptible to metastasis. Recent studies have shown that BAST, a class of traditional Chinese medicine (TCM) with the function of opening veins and dispersing blood stasis, significantly improve hemodynamics and microcirculation, prevent thrombosis and promote blood flow, and thereby inhibiting the invasion and metastasis of lung cancer. In the current review, we analyzed 51 active ingredients extracted from BAST. It was found that BAST and their active ingredients contribute to the prevention of invasion and metastasis of lung cancer through multiple mechanisms, such as regulation of EMT process, specific signaling pathway and metastasis-related genes, tumor blood vessel formation, immune microenvironment and inflammatory response of tumors.

CONCLUSIONS

BSAT and its active ingredients have showed promising anticancer activity and significantly inhibit the invasion and metastasis of lung cancer. A growing number of studies have realized their potential clinical significance in the therapy of lung cancer, which will provide substantial evidences for the development of new TCM for lung cancer therapy.

Biochemical features and therapeutic potential of α-Mangostin: Mechanism of action, medicinal values, and health benefits

α-Mangostin (α-MG) is a natural xanthone obtained from the pericarps of mangosteen. It exhibits excellent potential, including anti-cancer, neuroprotective, antimicrobial, antioxidant, and anti-inflammatory properties, and induces apoptosis. α-MG controls cell proliferation by modulating signaling molecules, thus implicated in cancer therapy. It possesses incredible pharmacological features and modulates crucial cellular and molecular factors. Due to its lesser water solubility and pitiable target selectivity, α-MG has limited clinical application. As a known antioxidant, α-MG has gained significant attention from the scientific community, increasing interest in extensive technical and biomedical applications. Nanoparticle-based drug delivery systems were designed to improve the pharmacological features and efficiency of α-MG. This review is focused on recent developments on the therapeutic potential of α-MG in managing cancer and neurological diseases, with a special focus on its mechanism of action. In addition, we highlighted biochemical and pharmacological features, metabolism, functions, anti-inflammatory, antioxidant effects and pre-clinical applications of α-MG.

Targeting autophagy and lipid metabolism in cancer stem cells

Cancer stem cells (CSCs) are a subset of cancer cells with self-renewal ability and tumor initiating properties. Unlike the other non-stem cancer cells, CSCs resist traditional therapy and remain a major cause of disease relapse. With the recent advances in metabolomics, various studies have demonstrated that CSCs have distinct metabolic properties. Metabolic reprogramming in CSCs contributes to self-renewal and maintenance of stemness. Accumulating evidence suggests that rewiring of energy metabolism is a key player that enables to meet energy demands, maintains stemness, and sustains cancer growth and invasion. CSCs use various mechanisms such as increased glycolysis, redox signaling and autophagy modulation to overcome nutritional deficiency and sustain cell survival. The alterations in lipid metabolism acquired by the CSCs support biomass production through increased dependence on fatty acid synthesis and β-oxidation and contribute to oncogenic signaling pathways. This review summarizes our current understanding of lipid metabolism in CSCs and how pharmacological regulation of autophagy and lipid metabolism influences CSC phenotype. Increased dependence on lipid metabolism appears as an attractive strategy to eliminate CSCs using therapeutic agents that specifically target CSCs based on their modulation of lipid metabolism.

Zinc Finger Protein 90 Knockdown Promotes Cisplatin Sensitivity via Nrf2/HO-1 Pathway in Ovarian Cancer Cell

Our study discussed the role of Zfp90 in ovarian cancer (OC) cell lines' sensitivity to cisplatin. We used two OC cell lines, SK-OV-3 and ES-2, to evaluate their role in cisplatin sensitization. The protein levels of p-Akt, ERK, caspase 3, Bcl-2, Bax, E-cadherin, MMP-2, MMP-9 and other drug resistance-related molecules, including Nrf2/HO-1, were discovered in the SK-OV-3 and ES-2 cells. We also used a human ovarian surface epithelial cell to compare the effect of Zfp90. Our outcomes indicated that cisplatin treatment generates reactive oxygen species (ROS) that modulate apoptotic protein expression. The anti-oxidative signal was also stimulated, which could hinder cell migration. The intervention of Zfp90 could greatly improve the apoptosis pathway and block the migrative pathway to regulate the cisplatin sensitivity in the OC cells. This study implies that the loss of function of Zfp90 might promote cisplatin sensitization in OC cells via regulating the Nrf2/HO-1 pathway to enhance cell apoptosis and inhibit the migrative effect in both SK-OV-3 and ES-2 cells.

Multivalent dipeptidyl peptidase IV fragment-nanogold complex inhibits cancer metastasis by blocking pericellular fibronectin

Inhibition of cancer metastasis is a fundamental challenge in cancer treatment. We have previously shown that metastasis of cancer cells in the lung is critically promoted by the interaction between the superficial dipeptidyl peptidase IV (DPP IV) expressed on lung endothelial cells and the pericellular polymeric fibronectin (polyFN) of circulating cancer cells. In the present study, we aimed to search for DPP IV fragments with high avidity to polyFN and develop FN-targeted gold nanoparticles (AuNPs) conjugated with DPP IV fragments for treating cancer metastasis. We first identified a DPP IV fragment encompassing amino acids 29-130 of DPP IV, designated DP4A, which contained FN-binding sites and could specifically bind to FN immobilized on gelatin agarose beads. Furthermore, we conjugated maltose binding protein (MBP)-fused DP4A proteins to AuNPs for fabricating a DP4A-AuNP complex and evaluated its FN-targeted activity in vitro and anti-metastatic efficacy in vivo. Our results show that DP4A-AuNP exhibited higher binding avidity to polyFN than DP4A by 9 folds. Furthermore, DP4A-AuNP was more potent than DP4A in inhibiting DPP IV binding to polyFN. In terms of polyFN-targeted effect, DP4A-AuNP interacted with FN-overexpressing cancer cells and was endocytosed into cells 10 to 100 times more efficiently than untargeted MBP-AuNP or PEG-AuNP with no noticeable cytotoxicity. Furthermore, DP4A-AuNP was superior to DP4A in competitive inhibition of cancer cell adhesion to DPP IV. Confocal microscopy analysis revealed that binding of DP4A-AuNP to pericellular FN induced FN clustering without altering its surface expression on cancer cells. Notably, intravenous treatment with DP4A-AuNP significantly reduced metastatic lung tumor nodules and prolonged the survival in the experimental metastatic 4T1 tumor model. Collectively, our findings suggest that the DP4A-AuNP complex with potent FN-targeted effects may have therapeutic potential for prevention and treatment of tumor metastasis to the lung.

Alpha-Mangostin Reduces Pericellular Fibronectin on Suspended Tumor Cells and Therapeutically, but Not Prophylactically, Suppresses Distant Metastasis

Major cancer deaths can be ascribed to distant metastasis to which the assembly of pericellular fibronectin (periFN) on suspended tumor cells (STCs) in the bloodstream that facilitate endothelial attachment can lead. Even though mangosteen pericarps (MP) extracts and the major component α-mangostin (α-MG) exhibit potent cancer chemopreventive properties, whether they can prophylactically and therapeutically be used as dietary nutraceuticals to prevent distant metastasis by suppressing periFN assembly on STCs within the circulation remains obscure. Immunofluorescence staining, MTT assays, flow cytometric assays, immunoblotting, and experimental metastasis mouse models were used to detect the effects of MP extracts or α-MG on periFN on STCs, tumor cell proliferation and apoptosis, the AKT activity, and tumor lung metastasis. The periFN assembly on STCs was significantly diminished upon treatments of STCs with either α-MG or MP extracts in a dose-dependent manner without inhibiting cell proliferation and viability due to increased AKT activity. Pretreatment of STCs with α-MG appeared to suppress tumor lung metastasis and prolong mouse survival rates. Oral gavage with MP extracts could therapeutically, but not prophylactically, prevent lung metastasis of STCs. We concluded that MP extracts or the major component α-MG may therapeutically serve as a potent anti-metastatic nutraceutical.

Hexokinases 2 promoted cell motility and distant metastasis by elevating fibronectin through Akt1/p-Akt1 in cervical cancer cells

Background

Hexokinases 2 (HK2) is a member of the hexokinases, linking with malignant tumor growth and distant metastasis. However, evidence regarding the potential role of HK2 in regulating cell motility and tumor metastasis during the cervical cancer malignant progression remains limited.

Methods

In vitro migration and invasion assay, in vivo metastasis experiments were performed to detect the effective of HK2 on regulating cell motility and tumor metastasis in cervical cancer cells. RNA-Seq was performed to explore the potential molecules that participate in HK2-mediated cell motility and tumor metastasis in cervical cancer cells. The correlation between HK2 and Akt1, p-Akt1, FN1 expression in cervical cancer cells and human squamous cervical carcinoma (SCC) samples was verified in this study.

Results

In this study, cervical cancer cells with exogenous HK2 expression exhibited enhanced cell motility and distant metastasis. Transcriptome sequencing analysis revealed that fibronectin (FN1) was significantly increased in HK2-overexpressing HeLa cells, and the PI3K/Akt signaling pathway was identified by KEGG pathway enrichment analysis. Further studies demonstrated that this promotion of cell motility by HK2 was probably a result of it inducing FN1, MMP2 and MMP9 expression by activating Akt1 in cervical cancer cells. Additionally, HK2 expression was altered with the changing of Akt1/p-Akt1 expression, implying that HK2 expression is also modulated by Akt1/p-Akt1. Moreover, the positive correlation between HK2 and Akt1, p-Akt1, FN1 expression in human squamous cervical carcinoma (SCC) samples was verified by using Pearson correlation analysis.

Conclusions

This study demonstrated that HK2 could activate Akt1 in cervical cancer cells, subsequently enhancing cell motility and tumor metastasis by inducing FN1, MMP2 and MMP9 expression. There likely exists an interactive regulatory mechanism between HK2 and Akt1 during the malignant process of cervical cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02312-0.

Targeting DNAJC19 overcomes tumor growth and lung metastasis in NSCLC by regulating PI3K/AKT signaling

Background

Some driver oncogenes are still unknown in non-small-cell lung cancer (NSCLC). DNAJC19, a major component of the translocation machinery of mitochondrial membranes, is a disease-associated protein. Herein, we report the role of DNAJC19 in NSCLC cell growth and metastasis.

Methods

Immunohistochemistry (IHC) was performed to investigate DNAJC19 expression in NSCLC clinical samples. For knockdown or overexpression assays in A549 or NCI-H1299 lung cancer cells, lentiviral vectors were used. After assessment of cell functions, DNAJC19-knockdown A549 cells were further applied to establish mouse xenograft and metastasis tumor models. Assessments based on the RNA-seq data, western blotting, PCR and IHC were performed for the mechanistic study.

Results

Expression of DNAJC19 was higher in tumors than in noncancerous adjacent tissues. Survival analysis indicated that low DNAJC19 levels were correlated with an increased progression-free survival rate. ShRNA-mediated knockdown of DNAJC19 markedly inhibited cell growth, viability, migration and invasion. Moreover, RNA-seq analysis revealed that the PI3K/AKT signaling pathway was involved in molecular events when A549 cells were treated with shDNAJC19. In addition, DNAJC19 knockdown decreased PI3Kp85a, AKT and p-AKT expression in A549 cells, and cellular functions were greatly rescued in DNAJC19-knockdown A549 cells by ectopic overexpression of AKT. Furthermore, tumor xenograft growth and lung metastasis were markedly repressed in the shDNAJC19 group compared to the control group. As expected, the expression levels of DNAJC19, PI3K and AKT in xenograft mouse samples were also lower in the shDNAJC19 group than in the shCtrl group.

Conclusions

DNAJC19 greatly promotes NSCLC cell growth and lung metastasis by regulating PI3K/AKT signaling, providing a novel therapeutic target for treating NSCLC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02054-z.

Anti-DLBCL efficacy of DCZ0825 in vitro and in vivo: involvement of the PI3K‒AKT‒mTOR/JNK pathway

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, characterized by high heterogeneity. The poor outcome of a portion of patients who suffer relapsing or resistant to conventional treatment impels the development of novel agents for DLBCL. DCZ0825 is a novel compound derived from pterostilbene and osalmide, whose antitumor activities have drawn our attention. In this study, we found that DCZ0825 exhibited high cytotoxicity toward DLBCL cell lines in a dose- and time-dependent manner, as revealed by cell counting kit-8 assay. Flow cytometry and western blot analysis results showed that DCZ0825 also promoted cell apoptosis via both extrinsic and intrinsic apoptosis pathways mediated by caspase. In addition, DCZ0825 induced cell cycle arrest in the G2/M phase by downregulating Cdc25C, CDK1, and Cyclin B1, thus interfering with cell proliferation. Further investigation showed the involvement of the phosphatidylinositol 3-kinase (PI3K)‒AKT‒mTOR/JNK pathway in the efficacy of DCZ0825 against DLBCL. Remarkably, DCZ0825 also exerted notable cytotoxic effects in vivo as well, with low toxicity to important internal organs such as the liver and kidney. Our results suggest that DCZ0825 may have the potential to become a novel anti-DLBCL agent or to replenish the conventional therapeutic scheme of DLBCL.

The Fibronectin Expression Determines the Distinct Progressions of Malignant Gliomas via Transforming Growth Factor-Beta Pathway

Due to the increasing incidence of malignant gliomas, particularly glioblastoma multiforme (GBM), a simple and reliable GBM diagnosis is needed to screen early the death-threaten patients. This study aimed to identify a protein that can be used to discriminate GBM from low-grade astrocytoma and elucidate further that it has a functional role during malignant glioma progressions. To identify proteins that display low or no expression in low-grade astrocytoma but elevated levels in GBM, glycoprotein fibronectin (FN) was particularly examined according to the mining of the Human Protein Atlas. Web-based open megadata minings revealed that FN was mainly mutated in the cBio Cancer Genomic Portal but dominantly overexpressed in the ONCOMINE (a cancer microarray database and integrated data-mining platform) in distinct tumor types. Furthermore, numerous different cancer patients with high FN indeed exhibited a poor prognosis in the PrognoScan mining, indicating that FN involves in tumor malignancy. To investigate further the significance of FN expression in glioma progression, tumor specimens from five malignant gliomas with recurrences that received at least two surgeries were enrolled and examined. The immunohistochemical staining showed that FN expression indeed determined the distinct progressions of malignant gliomas. Furthermore, the expression of vimentin (VIM), a mesenchymal protein that is strongly expressed in malignant cancers, was similar to the FN pattern. Moreover, the level of epithelial-mesenchymal transition (EMT) inducer transforming growth factor-beta (TGF-β) was almost recapitulated with the FN expression. Together, this study identifies a protein FN that can be used to diagnose GBM from low-grade astrocytoma; moreover, its expression functionally determines the malignant glioma progressions via TGF-β-induced EMT pathway.

Pterostilbene promotes mitochondrial apoptosis and inhibits proliferation in glioma cells

Glioma is the most general primary and lethal intracranial malignant tumor. Pterostilbene (PTE), an analog of stilbene and resveratrol, has attracted attention in recent years due to its significant antitumor activity in multiple solid tumors; however, its effect on drug-resistant glioma cells and the underlying mechanism have not yet been reported. In this study, we found that pterostilbene inhibited proliferation, induced intrinsic mitochondria-mediated apoptosis and caused S phase arrest, inhibited migration and excessive invasion in glioma cells. Pretreatment with the pan-caspase-inhibitor Z-VAD-FMK attenuated the PTE-induced apoptosis of glioma cells. Moreover, PTE significantly increased the production of reactive oxygen species (ROS) and reduce the mitochondrial membrane potential (MMP). Inhibition of ROS with N-acetyl-l-cysteine not only rescued PTE-induced reduction of cellular viability but also prevented glioma cell apoptosis. We also discovered ERK 1/2 and JNK signaling pathways were activated by PTE and contributed to induce glioma cell apoptosis. In addition, specific inhibitors of ERK 1/2 and JNK attenuated PTE-induced apoptosis. Besides, PTE significantly reduced tumor volume and prolonged median survival of tumor-bearing rats in vivo. In summary, the results of this study indicate that the anti-tumor effect of PTE on glioma cells may provide a new treatment option for glioma patients.

Pterostilbene inhibits gallbladder cancer progression by suppressing the PI3K/Akt pathway

Gallbladder cancer is the most common malignant tumor of the biliary system and is characterized by difficulty to diagnose in early stages, a high degree of malignancy, and poor prognosis. Finding new drugs may improve the prognosis for this dismal cancer. Herein, we investigated the potential application of pterostilbene (PTS) against gallbladder cancer in vivo and in vitro. PTS potently inhibited cell proliferation, migration and invasion of gallbladder cancer cells. Moreover, PTS also had a function of inducing apoptosis in vitro. Meanwhile, PTS reversed EMT with a correlated inhibition of PI3K/Akt activation. Tumor xenograft models showed that PTS inhibited tumor growth and had low toxicity in vivo, which were consistent with the in vitro data. These findings indicate that PTS arrests cell growth through inhibition of PI3K/AKT signaling and is a potential drug for the therapy of gallbladder cancer.

Anti-Stem Cell Property of Pterostilbene in Gastrointestinal Cancer Cells

Pterostilbene (PTE) is a natural sterbenoid contained in blueberries that has an antioxidant effect. In contrast, PTE also generates oxidative stress in cancer cells and provides an antitumor effect. Here, we examined the potential mechanism of this contrasting effect of PTE using three gastrointestinal cancer cell lines, namely CT26, HT29, and MKN74. PTE showed a dose-dependent inhibition of cell proliferation, sphere-forming ability, and stem cell marker expression in all three cell lines. Furthermore, the cells treated with PTE showed an increase in mitochondrial membrane potential and an increase in mitochondrial oxidative stress and lipid peroxide. Upon concurrent treatment with vitamin E, N-acetyl-L-cysteine, and PTE, the PTE-induced mitochondrial oxidative stress and growth inhibition were suppressed. These findings indicate that PTE induces oxidative stress in cancer cells, suppresses stemness, and inhibits proliferation. These antitumor effects of PTE are considered to be useful in cancer treatment.

MicroRNA-146a suppresses tumor malignancy via targeting vimentin in esophageal squamous cell carcinoma cells with lower fibronectin membrane assembly

Background

Esophageal squamous cell carcinoma (ESCC) is widely prevalent in Taiwan, and high metastatic spread of ESCC leads to poor survival rate. Fibronectin (FN) assembly on the cell membrane may induce ESCC mobility. MicroRNAs (MiRNAs) are abundant in and participate in tumorigenesis in many cancers. However, the role of MiRNA in FN assembly-related ESCC mobility remains unexplored.

Methods

We divided ESCC CE81T cells into high-FN assembly (CE81^FN+) and low-FN assembly (CE81^FN−) groups by flow cytometry. MiRNA microarray analysis identified miR-146a expression as the most down-regulated miRNA in comparison of CE81^FN+ and CE81^FN− cells.

Results

Cell proliferation and migration were decreased when CE81^FN+ cells overexpressed transgenic miR-146a compared to the parental cells, indicating an inverse correlation between low miR-146a expression and high proliferation as well as motility of FN assembly ESCC cells. Furthermore, vimentin is the target gene of miR-146a involved in ESCC tumorigenesis. MiR-146a suppressed cell proliferation, migration and invasion of CE81^FN+ cells through the inhibition of vimentin expression, as confirmed by real-time PCR, Western blotting and Transwell™ assay. Analysis of one hundred and thirty-six paired ESCC patient specimens revealed that low miR-146a and high vimentin levels were frequently detected in tumor, and that the former was associated with late tumor stages (III and IV). Notably, either low miR-146a expression or high vimentin level was significantly associated with poor overall survival rate among ESCC patients.

Conclusions

This is the first report to link FN assembly in the cell membrane with miR-146a, vimentin and ESCC tumorigenesis both in vitro and in ESCC patients.

Recent Advances in Synthesis, Bioactivity, and Pharmacokinetics of Pterostilbene, an Important Analog of Resveratrol

Pterostilbene is a natural 3,5-dimethoxy analog of resveratrol. This stilbene compound has a strong bioactivity and exists widely in Dalbergia and Vaccinium spp. Besides natural extraction, pterostilbene can be obtained by biosynthesis. Pterostilbene has become popular because of its remarkable pharmacological activities, such as anti-tumor, anti-oxidation, anti-inflammation, and neuroprotection. Pterostilbene can be rapidly absorbed and is widely distributed in tissues, but it does not seriously accumulate in the body. Pterostilbene can easily pass through the blood-brain barrier because of its low molecular weight and good liposolubility. In this review, the studies performed in the last three years on resources, synthesis, bioactivity, and pharmacokinetics of pterostilbene are summarized. This review focuses on the effects of pterostilbene on certain diseases to explore its targets, explain the possible mechanism, and look for potential therapeutic applications.

Depleting RhoA/Stress Fiber-Organized Fibronectin Matrices on Tumor Cells Non-Autonomously Aggravates Fibroblast-Driven Tumor Cell Growth

Fibronectin (FN) expressed by tumor cells has been known to be tumor suppressive but the pericellular FN (periFN) assembled on circulating tumor cells appears to evidently promote distant metastasis. Whereas the regulation of periFN assembly in suspended cells has currently been under investigation, how it is regulated in adherent tumor cells and the role of periFN in primary tumor growth remain elusive. Techniques of RNAi, plasmid transfections, immunoblotting, fluorescence/immunohistochemistry staining, cell proliferation assays, and primary tumor growth in C57BL6 mice and Fischer 344 rats were employed in this study. We found that endogenously synthesized FN in adherent tumor cells was required for periFN assembly which was aligned by RhoA-organized actin stress fiber (SF). Depleting periFN on adherent tumor cells congruently promoted in vivo tumor growth but surprisingly did not autonomously impact on in vitro tumor cell proliferation and apoptosis, suggestive of a non-autonomous role of periFN in in vivo tumor growth. We showed that the proliferative ability of shFN-expressing tumor cells was higher than shScramble cells did in the presence of fibroblasts. Altogether, these results suggested that depriving RhoA/SF-regulated periFN matrices non-autonomously promotes fibroblast-mediated tumor cell growth.

Fibronectin and colorectal cancer: signaling pathways and clinical implications

Colorectal cancer (CRC) is the fourth leading cause of cancer deaths worldwide, with poor prognosis mainly related to metastasis. Fibronectin (FN), a vital component of the extracellular matrix (ECM), has been found involved in tumorigenesis and malignant progression in different types of malignancy. Numerous studies have indicated the distinct expression of FN in various cancers and demonstrated the different functions of FN in the proliferation, migration, and invasion of cancers. Meanwhile, FN isoforms have been extensively used for targeted drug delivery and imaging for tumors. Although a growing number of studies on FN in CRC have been reported, integrated reviews on the relationship between FN and CRC are rare. In this review, we will summarize the association between FN and CRC, including the signaling pathways and molecules involved in, as well as potential diagnostic and therapeutic values of FN for patients with CRC.

Identification of a natural compound, sesamin, as a novel TRPM8 antagonist with inhibitory effects on prostate adenocarcinoma

Transient receptor potential melastatin 8 (TRPM8) is a calcium ion-permeable cation channel that is used as a prognostic marker and therapeutic target for different tumor types. To identify natural selective TRPM8 antagonists, we tested 158 traditional Chinese medicine (TCM) compounds for the ability to inhibit TRPM8. Calcium mobilization assays were used to evaluate the 158 TCM compound components in HEK293 cells stably expressing TRPM8. An identified putative TRPM8 antagonist, sesamin, was further evaluated. Publicly available cancer OMICS data were used to explore the expression of TRPM8, its gene regulatory network, and the survival of patients with prostate adenocarcinoma (PRAD). The cytotoxicity and specificity of sesamin to TRPM8 were tested in HEK293/TRPM8 cells. The effect of sesamin on cell proliferation in PRAD cell lines was assessed. Sesamin selectively inhibited TRPM8 in HEK293/TRPM8 cells (IC50: 9.78 μM), and a molecular docking study confirmed the binding of sesamin to TRPM8. TRPM8 was highly overexpressed in PRAD, and high TRPM8 expression was associated with poor survival of PRAD patients. Functional network analysis suggested that TRPM8 has key effects on proliferation, survival, and invasion of prostate cancer cells. Cell proliferation assays supported these findings and showed that sesamin inhibited the proliferation of PRAD cell lines DU145 and LNCaP cells. These data revealed that abnormal TRPM8 expression is associated with PRAD and that sesamin is a new anti-PRAD candidate drug, exerting inhibitory effects on TRPM8.

Heme oxygenase-1 inhibition mediates Gas6 to enhance bortezomib-sensitivity in multiple myeloma via ERK/STAT3 axis

Chemoresistance is still a critical challenge for efficient treatment of multiple myeloma (MM) during the bortezomib-based chemotherapy. Recent studies have suggested that heme oxygenase-1 (HO-1) is involved in apoptosis, proliferation and chemoresistance in cancer cells. Here we aim to investigate the role and mechanism of HO-1 in bortezomib-sensitivity to myeloma cells. In the study population, we found that HO-1 was highly expressed in CD138⁺ primary myeloma cells, which was positively associated with Gas6 expression and Gas6 plasma levels in MM patients. Downregulation of HO-1 using pharmacological inhibitor ZnPPIX or siRNA knockdown significantly enhanced myeloma cell sensitivity to bortezomib in human primary CD138⁺ cells, U266 and RPMI8226 cell lines. Mechanistically, HO-1 regulated Gas6 production via ERK/STAT3 axis. Combination with HO-1 inhibition increased bortezomib-induced apoptosis and antiproliferative effects via suppressing Gas6 production. These findings suggest that combination of bortezomib and HO-1 inhibitor may serve as a promising therapeutic target against bortezomib-resistant MM.

Pterostilbene Inhibits FcεRI Signaling through Activation of the LKB1/AMPK Pathway in Allergic Response

In this study, the role and mechanism of pterostilbene (Pts) in mast cell degranulation in vitro and in vivo were investigated. The results showed that Pts inhibited mast cell-mediated local passive allergic reactions in mice. In addition, treatment with Pts reduced both histamine release and calcium influx in rat peritoneal mast cells and RBL-2H3 cells and reduced IgE-mediated mast cell activation. Furthermore, the mechanism underlying Pts inhibition of mast cell signaling was probed via studying the effects of Pts on liver kinase B1 (LKB1), including the use of the LKB1 activator metformin and siRNA knockdown of LKB1. The data showed that Pts reduced the release of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, leukotriene C4, and prostaglandin D2 in mast cells by activating the LKB1/adenosine monophosphate (AMP)-activated protein kinase (AMPK) signaling pathway. Furthermore, Pts inhibited phosphorylation of FcεRI and FcεRI-mediated degranulation in RBL-2H3 cells. These effects were attenuated after LKB1 knockdown. Taken together, Pts could inhibit FcεRI signaling through activation of the LKB1/AMPK signaling pathway in IgE-mediated mast cell activation. Thus, Pts might be an effective therapeutic agent for mast cell-mediated allergic diseases.

Fibronectin in Cancer: Friend or Foe

The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.

Osimertinib and pterostilbene in EGFR-mutation-positive non-small cell lung cancer (NSCLC)

Monotherapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) still leads to incomplete responses in most EGFR-mutation positive non-small cell lung cancer (NSCLC) patients, often due to acquired resistance through activation of parallel compensatory pathways. We have previously shown that co-targeting EGFR, signal transducer and activator of transcription 3 (STAT3), and Src-yes-associated protein 1 (YAP1) was highly synergistic in vitro and in vivo. In the present study, we treated EGFR-mutation positive cell lines with the combination of osimertinib plus a natural compound, pterostilbene, which has been reported to abrogate Src and STAT3 activation.

Methods: Cell viability assays and immunoblotting were performed to reveal the mechanisms of action of pterostilbene, osimertinib and pterostilbene plus osimertinib in five EGFR-mutation positive NSCLC and one triple negative breast cancer (TNBC) cell lines.

Results: Osimertinib plus pterostilbene yielded synergistic effects in all EGFR-mutation positive NSCLC cell lines investigated. Surprisingly, pterostilbene alone did not inhibit, nor downregulate Src phosphorylation in the EGFR-mutation positive NSCLC cell lines or the TNBC cell line, MDA-MB-231. However, the double combination of osimertinib plus pterostilbene reversed the osimertinib-induced STAT3, YAP1, and CUB domain-containing protein-1 (CDCP1) phosphorylation and slightly suppressed Src phosphorylation in PC9 and H1975 cells.

Conclusion: The results of this study indicate that pterostilbene may be used to abrogate the activated resistance pathways of single osimertinib treatment in EGFR-mutation positive NSCLC. Future studies should focus on in vivo translation and confirmation of these results.

[Emerging Actions of Pterostilebene on Cancer Research]

紫檀芪（3, 5-二甲氧基-4’-羟基二苯乙烯）是一种主要存在于蓝莓、葡萄和花榈木中的多酚类化合物。已有的研究发现紫檀芪具有抗肺癌、乳腺癌、胃癌、结肠癌等多种肿瘤的抗癌作用。其作用机制涉及调控影响多种肿瘤生物学特性。此外，紫檀芪具有比白藜芦醇更高的生物利用度和生物活性，其抗肿瘤作用和机制值得深入探讨和研究。

The Establishment of a Lung Colonization Assay for Circulating Tumor Cell Visualization in Lung Tissues

Metastasis is the major cause of cancer death. The role of circulating tumor cells (CTCs) in promoting cancer metastasis, in which lung colonization by CTCs critically contributes to early lung metastatic processes, has been vigorously investigated. As such, animal models are the only approach that captures the full systemic process of metastasis. Given that problems occur in previous experimental designs for examining the contributions of CTCs to blood vessel extravasation, we established an in vivo lung colonization assay in which a long-term-fluorescence cell-tracer, carboxyfluorescein succinimidyl ester (CFSE), was used to label suspended tumor cells and lung perfusion was performed to clear non-specifically trapped CTCs prior to lung removal, confocal imaging, and quantification. Polymeric fibronectin (polyFN) assembled on CTC surfaces has been found to mediate lung colonization in the final establishment of metastatic tumor tissues. Here, to specifically test the requirement of polyFN assembly on CTCs for lung colonization and extravasation, we performed short term lung colonization assays in which suspended Lewis lung carcinoma cells (LLCs) stably expressing FN-shRNA (shFN) or scramble-shRNA (shScr) and pre-labeled with 20 μM of CFSE were intravenously inoculated into C57BL/6 mice. We successfully demonstrated that the abilities of shFN LLC cells to colonize the mouse lungs were significantly diminished in comparison to shScr LLC cells. Therefore, this short-term methodology may be widely applied to specifically demonstrate the ability of CTCs within the circulation to colonize the lungs.

Emerging role of lipid metabolism alterations in Cancer stem cells

BACKGROUND

Cancer stem cells (CSCs) or tumor-initiating cells (TICs) represent a small population of cancer cells with self-renewal and tumor-initiating properties. Unlike the bulk of tumor cells, CSCs or TICs are refractory to traditional therapy and are responsible for relapse or disease recurrence in cancer patients. Stem cells have distinct metabolic properties compared to differentiated cells, and metabolic rewiring contributes to self-renewal and stemness maintenance in CSCs.

MAIN BODY

Recent advances in metabolomic detection, particularly in hyperspectral-stimulated raman scattering microscopy, have expanded our knowledge of the contribution of lipid metabolism to the generation and maintenance of CSCs. Alterations in lipid uptake, de novo lipogenesis, lipid droplets, lipid desaturation, and fatty acid oxidation are all clearly implicated in CSCs regulation. Alterations on lipid metabolism not only satisfies the energy demands and biomass production of CSCs, but also contributes to the activation of several important oncogenic signaling pathways, including Wnt/β-catenin and Hippo/YAP signaling. In this review, we summarize the current progress in this attractive field and describe some recent therapeutic agents specifically targeting CSCs based on their modulation of lipid metabolism.

CONCLUSION

Increased reliance on lipid metabolism makes it a promising therapeutic strategy to eliminate CSCs. Targeting key players of fatty acids metabolism shows promising to anti-CSCs and tumor prevention effects.

Pterostilbene inhibits MTA1/HDAC1 complex leading to PTEN acetylation in hepatocellular carcinoma

PURPOSE

The aim of this study is to investigate the inhibition of cancer growth by pterostilbene through Metastasis-Associated Protein 1 (MTA1) and the histone deacetylase 1 (HDAC1) complex in hepatocellular carcinoma (HCC).

METHODS

We investigate the antitumor effects of pterostilbene (PTER) in HCC. The SMMC-7721 hepatoma cell line was cultured and treated with PTER for different time depending on the experiment. After treatment, we tested the cellular expression of proteins by Western blot and the expression of MTA1 mRNA by real-time PCR. And the immunoprecipitation was performed to confirm the acetylation in PTEN. Animal models have been established to confirm the anti-cancer effects of PTER.

RESULTS

PTER treatment could downregulate the expression of MTA1, and HDAC1 and elevates the Ac-PTEN ratio in tumors. The results suggest that PTER can decrease the expression of MTA1 and destabilize the MTA1/HDAC1 complex allowing acetylation/activation of PTEN on Lys402 site. The expression of MTA1 may be linked to cell apoptosis and invasion in HCC.

CONCLUSION

We demonstrated that PTER suppressed the growth, and invasion of HCC and was effective in regulating the levels of the MTA1/HDAC1/NuRD complex, promoting PTEN acetylation and apoptosis in HCC. Our findings suggest that the novel epigenetic nature of PTER anticancer activity opens up new avenues for primary chemoprevention, as well as anticancer and antimetastatic treatment.

Pterostilbene modulates the suppression of multidrug resistance protein 1 and triggers autophagic and apoptotic mechanisms in cisplatin-resistant human oral cancer CAR cells via AKT signaling

Pterostilbene is a natural polyphenolic compound that is primarily found in fruits, such as blueberries and has a similar structure to resveratrol. Pterostilbene exhibits antioxidant, anti-inflammatory and antitumor activity but the effects of pterostilbene on drug-resistant oral cancer cells and its underlying mechanisms of action have not yet been explored. Therefore, the present study was performed to clarify the anticancer effects of pterostilbene on cisplatin-resistant human oral cancer CAR cells. The results demonstrated that CAR cells exhibited marked shrinkage, cell membrane breakage and autophagic vacuole formation following treatment with pterostilbene. Pterostilbene also effectively inhibited cell viability and suppressed cell confluence in a time- and concentration-dependent manner. Probing with acridine orange, monodansylcadaverine and LysoTracker Red demonstrated that the number of acidic vesicular organelles was increased, indicating increased autophagy. Furthermore, Heochst 33342 staining determined that DNA condensation, a characteristic of apoptosis, was enhanced following treatment with pterostilbene. Furthermore, pterostilbene upregulated mRNA levels of LC3-II and Atg12, as well as the expression of Atgs/Beclin-1/LC3-associated signaling, suggesting that it enhances autophagy. The autophagy inhibitors 3-methyladenine and chloroquine were used to confirm that pterostilbene induces autophagy. It was also determined that pterostilbene triggered caspase-dependent apoptosis by directly testing DNA breakage and using the pan-caspase inhibitor carbobenzoxyvalyl-alanyl-aspartyl fluoromethyl ketone. The results demonstrated that pterostilbene mediates the apoptosis of CAR cells via the intrinsic apoptotic cascade. In addition, pterostilbene inhibited MDR1 expression and the phosphorylation of AKT on the Ser473 site in CAR cells. Therefore, pterostilbene may elicit an oral anticancer response in drug-resistant cells and may be used as a chemotherapeutic adjuvant to treat patients with oral cancer.

Apoptotic and Nonapoptotic Activities of Pterostilbene against Cancer

Cancer is a major cause of death. The outcomes of current therapeutic strategies against cancer often ironically lead to even increased mortality due to the subsequent drug resistance and to metastatic recurrence. Alternative medicines are thus urgently needed. Cumulative evidence has pointed out that pterostilbene (trans-3,5-dimethoxy-4-hydroxystilbene, PS) has excellent pharmacological benefits for the prevention and treatment for various types of cancer in their different stages of progression by evoking apoptotic or nonapoptotic anti-cancer activities. In this review article, we first update current knowledge regarding tumor progression toward accomplishment of metastasis. Subsequently, we review current literature regarding the anti-cancer activities of PS. Finally, we provide future perspectives to clinically utilize PS as novel cancer therapeutic remedies. We, therefore, conclude and propose that PS is one ideal alternative medicine to be administered in the diet as a nutritional supplement.