Enterolactone Induces G1-phase Cell Cycle Arrest in Nonsmall Cell Lung Cancer Cells by Downregulating Cyclins and Cyclin-dependent Kinases

Anticancer potential of flaxseed lignans, their metabolites and synthetic counterparts in relation with molecular targets: current challenges and future perspectives

Lignans are known dietary polyphenols found in cereals, plants and seeds. Flaxseed is one of the major sources of lignans mainly existing in the form of secoisolariciresinol diglucoside (SDG) which can be metabolised by the gut microbes into secoisolariciresinol (SECO) and mammalian lignan (enterodiol and enterolactone) that are easily absorbed through the intestines. Numerous studies reveal that flaxseed lignans (FLs) can be promising chemotherapeutics/chemopreventive agents. Their anticancer activity can occur through the induction of apoptosis, inhibition of cell proliferation, and the hindering of metastasis and angiogenesis. The anti-carcinogenesis of flaxseed lignans is achieved through multiple molecular mechanisms involving biochemical entities such as cellular kinases, cell cycle mediators, transcription factors, inflammatory cytokines, reactive oxygen species, and drug transporters. This review summarizes the bioavailability of FLs, their anticancer mechanisms in relevance to molecular targets, safety, and the scope of future research. Overall, FLs can be utilized in functional foods, dietary supplements, and pharmaceuticals for the management and prevention of cancers.

Synthetic Secoisolariciresinol Diglucoside (LGM2605) Prevents Asbestos-Induced Inflammation and Genotoxic Cell Damage in Human Mesothelial Cells

Although alveolar macrophages play a critical role in malignant transformation of mesothelial cells following asbestos exposure, inflammatory and oxidative processes continue to occur in the mesothelial cells lining the pleura that may contribute to the carcinogenic process. Malignant transformation of mesothelial cells following asbestos exposure occurs over several decades; however, amelioration of DNA damage, inflammation, and cell injury may impede the carcinogenic process. We have shown in an in vitro model of asbestos-induced macrophage activation that synthetic secoisolariciresinol diglucoside (LGM2605), given preventively, reduced inflammatory cascades and oxidative/nitrosative cell damage. Therefore, it was hypothesized that LGM2605 could also be effective in reducing asbestos-induced activation and the damage of pleural mesothelial cells. LGM2605 treatment (50 µM) of huma n pleural mesothelial cells was initiated 4 h prior to exposure to asbestos (crocidolite, 20 µg/cm2). Supernatant and cells were evaluated at 0, 2, 4, and 8 h post asbestos exposure for reactive oxygen species (ROS) generation, DNA damage (oxidized guanine), inflammasome activation (caspase-1 activity) and associated pro-inflammatory cytokine release (IL-1β, IL-18, IL-6, TNFα, and HMGB1), and markers of oxidative stress (malondialdehyde (MDA) and 8-iso-prostaglandin F2a (8-iso-PGF2α). Asbestos induced a time-dependent ROS increase that was significantly (p < 0.0001) reduced (29.4%) by LGM2605 treatment. LGM2605 pretreatment also reduced levels of asbestos-induced DNA damage by 73.6% ± 1.0%. Although levels of inflammasome-activated cytokines, IL-1β and IL-18, reached 29.2 pg/mL ± 0.7 pg/mL and 43.9 pg/mL ± 0.8 pg/mL, respectively, LGM2605 treatment significantly (p < 0.0001) reduced cytokine levels comparable to baseline (non-asbestos exposed) values (3.8 pg/mL ± 0.2 pg/mL and 5.4 pg/mL ± 0.2 pg/mL, respectively). Furthermore, levels of IL-6 and TNFα in asbestos-exposed mesothelial cells were high (289.1 pg/mL ± 2.9 pg/mL and 511.3 pg/mL ± 10.2 pg/mL, respectively), while remaining undetectable with LGM2605 pretreatment. HMGB1 (a key inflammatory mediator and initiator of malignant transformation) release was reduced 75.3% ± 0.4% by LGM2605. Levels of MDA and 8-iso-PGF2α, markers of oxidative cell injury, were significantly (p < 0.001) reduced by 80.5% ± 0.1% and 76.6% ± 0.3%, respectively. LGM2605, given preventively, reduced ROS generation, DNA damage, and inflammasome-activated cytokine release and key inflammatory mediators implicated in asbestos-induced malignant transformation of normal mesothelial cells.

Secoisolariciresinol diglucoside induces pyroptosis by activating caspase-1 to cleave GSDMD in colorectal cancer cells

Secoisolariciresinol diglucoside (SDG) is the main component of lignans with various biological activities, including anticancer activity. However, whether SDG has obvious anticancer effects on colorectal cancer (CRC) is unclear. Pyroptosis, a form of programmed cell death, has received increasing attention in cancer‐related research. In this study, we aimed to test the anticancer properties and relatecd functional mechanisms of SDG. we found that SDG not only inhibited the cell viability of HCT116 cells, but also induced HCT116 cells to swell with apparent large bubbles, which are typical signs of pyroptosis. Furthermore, SDG induced cell pyroptosis by enhancing cleavage of the N‐terminal fragment of gasdermin D (GSDMD) in CRC cells, accompanied by increased caspase‐1 cleavage. Consistent with this, SDG‐induced GSDMD‐N‐terminal fragment cleavage and pyroptosis were reduced by siRNA‐mediated silencing of caspase‐1 or treatment with the specific caspase‐1 inhibitor VX‐765 treatment, suggesting that active caspase‐1 further induces pyroptosis. A mechanistic study showed that SDG induced reactive oxygen species (ROS) accumulation and inhibits phosphatidylinositol 3‐kinase (PI3K) phosphorylation and increases pyroptosis, while increasing GSDMD and caspase‐1 cleavage and enhancing expression of BCL2‐associated X (BAX), which could be rescued by the ROS scavenger (NAC), suggesting that SDG‐induced GSDME‐dependent pyroptosis is related to the ROS/PI3K/AKT/BAX‐mitochondrial apoptotic pathway. In vivo results showed that SDG significantly inhibited tumor growth and induced pyroptosis in the HCT116‐CRC nude mouse model. In conclusion, our findings suggest that the anticancer activity of SDG in CRC is associated with the induction of GSDMD‐dependent pyroptosis by SDG through the generation of ROS/P13K/AKT/BAK‐mitochondrail apoptosis pathway, providing insights into SDG in its potential new application in cancer treatment.

Antitumour Activity of Muricatacin Isomers and its Derivatives in Human Colorectal Carcinoma Cell HCT116

BACKGROUND AND PURPOSE

Colorectal cancer is one of the leading causes of cancer-related death in elderly people. The natural product muricatacin is an important member of the γ-lactone family, and it has exhibited antitumour activity in multiple cancer cell lines; however, the antitumour activities of muricatacin stereoisomers and their derivatives in colorectal cancer cells have not yet been systematically explored.

METHODS

The colorectal carcinoma cell line HCT116 was investigated in this study. Cell proliferation was assessed by MTT assay or crystal violet staining. Cell cycle arrest and cell apoptosis were evaluated by flow cytometry assay. The expression levels of p53, p21, cyclin E, cyclin D1, caspase-3, cleaved caspase-3, caspase-9, cleaved caspase-9 and LC3B were measured using western blot analysis. Autophagy induced by M2 was monitored by immunofluorescence assay with an antibody against LC3B.

RESULTS

Cell proliferation assays showed that both naturally occurring muricatacin (M4) and its synthetic stereoisomer (M2) are potent cell growth inhibitors in HCT116 cells, with IC50 values of 79.43 and 83.17μM, respectively; these values are much lower than those of the other two isomers, M1 and M3, and those of the sixmembered lactone analogues. The flow cytometry analysis revealed that M2 and M4 induced significant cell cycle arrest during G0/G1 phase and caused relatively low apoptosis rates in HCT116 cells. Further analysis indicated that M2 caused p53-independent p21 induction and cyclin E/cyclin D1 downregulation. In addition, M2 also markedly induced autophagy in the early stage of administration.

CONCLUSION

Our results suggested that muricatacins possess potent antitumour activity against the colorectal carcinoma cell line HCT116 through inducing G0/G1 phase cell cycle arrest and autophagy in the early stage of administration.

[Expression of CDC25A in non-small cell lung cancer and its relationship with let-7 gene]

OBJECTIVE

To investigate the expression of CDC25A in non- small cell lung cancer (NSCLC) tissues and explore its correlation with the clinicpathological features of the patients and the expressions of let-7a1 and let-7c.

METHODS

We collected surgical specimens of pathologically confirmed NSCLC tissues and paired adjacent lung tissues from 44 patients and tissues of benign lung lesions from 9 patients. The expressions of CDC25A protein and mRNA in the tissues were detected by immunohistochemistry and fluorescence quantitative RT-PCR, respectively; the expressions of let-7a1 and let-7c mRNA were detected using tail-adding fluorescence quantitative RT-PCR.

RESULTS

The positivity rate of CDC25A protein expression was significantly higher in NSCLC tissues than in the adjacent tissues and benign pulmonary lesions (P < 0.05). CDC25A protein expression in NSCLC was not correlated with the patients' age, gender, pathological type, degree of tumor differentiation, or clinical stages (P > 0.05), and was significantly correlated with smoking and lymph node metastasis (P < 0.05). CDC25A mRNA expression was also significantly higher in NSCLC tissues than in the adjacent tissues and benign pulmonary lesions (F=6.33, P < 0.05), and was similar between the latter two tissues (P > 0.05). Pearson correlation analysis showed that CDC25A expression had a significant negative correlation with let-7c expression in both NSCLC tissues (r=-0.42) and adjacent lung tissues (r=-0.40) but was not correlated with let-7a1 expression.

CONCLUSIONS

The expression level of CDC25A is significantly increased in NSCLC with a negative correlation with Let-7c expression, which identifies CDC25A as a possible downstream target gene of Let-7c.

α-Cyperone inhibits the proliferation of human cervical cancer HeLa cells via ROS-mediated PI3K/Akt/mTOR signaling pathway

Cervical cancer is the fourth leading killer of female cancer patients worldwide. Each year more than half a million women are diagnosed with cervical cancer and the disease results in over 300, 000 deaths. α-Cyperone is known as the principal active ingredient in the Cyperus rotundus (Family: Cyperaceae). However, the effects of α-Cyperone on cancers, especially on cervical cancer, are yet to be explored. In the present study, the underlying mechanism of the anti-tumor activity of α-Cyperone against HeLa cells was investigated. The results showed that α-Cyperone inhibited proliferation and induced apoptosis in HeLa cells. Mechanistically, α-Cyperone promoted HeLa cells apoptosis via a mitochondrial apoptotic pathway, which was proved by increased level of intracellular reactive oxygen species (ROS) and upregulated expression of cytochrome c, cleaved caspase-3, PARP, and Bax. Further RNA-sequencing revealed α-Cyperone inhibited the activation of PI3K/Akt/mTOR signaling pathway in HeLa cells, which confirmed by PI3K inhibitor and agonist. The PI3K inhibitor (LY294002) synergized with α-Cyperone in arresting the growth of HeLa cells, whereas the PI3K agonist (IGF-1) abrogated such an effect. Interestingly, the expression of PD-L1 was attenuated by both α-Cyperone and LY294002, while the supplement of IGF-1 rescued the low expression of PD-L1. In conclusion, our results reveal that the inhibitory effect of α-Cyperone on HeLa cell growth is triggered via the ROS-mediated PI3K/Akt/mTOR signaling pathway and closely related to a decline in the PD-L1 expression.

Arsenic trioxide and BIBR1532 synergistically inhibit breast cancer cell proliferation through attenuation of NF-κB signaling pathway

AIMS

Despite the remarkable anti-proliferative effects of Arsenic trioxide (ATO) in breast cancer cells, the requirement of high, toxic concentrations to induce apoptosis may cause serious side effects in patients. In the present study, we aimed to use BIBR1532, an hTERT inhibitor, in combination with ATO to sensitize MCF7 and MDA-231 cells to lower concentrations of ATO.

MAIN METHODS

Breast cancer cell lines MCF7 and MDA-231 were cultured and treated with different doses of ATO and BIBR1532 for 48 h and its effects on cell survival and proliferation were analyzed by MTT, crystal violet staining, colony formation assay, cell cycle, AnnexinV/PI and Real-time PCR tests.

KEY FINDINGS

ATO and BIBR1532 synergistically inhibited proliferation and colony-forming ability of breast cancer cells. Besides, BIBR1532 augmented ATO-induced cytotoxic effects via triggering G1 cell cycle arrest and induction of apoptosis coupled with the down-regulation of NF-κB target genes that were involved in cell cycle progression (e.g. CCND1 and CDK6) and prevention of apoptosis such as Bcl-2, Bcl-xl, c-IAP2, and Survivin Respectively. Moreover, ATO-BIBR1532 significantly reduced the mRNA expression level of RELA, NFKB1, and several validated target genes of the NF-κB signaling pathway including NFKBIA, VEGFC, c-Myc, and hTERT.

SIGNIFICANCE

The combination of ATO and BIBR1532 synergistically induced its anti-proliferative effect in breast cancer cells by targeting the two key cancer-related pathways, hTERT and NF-κB, and disrupting their feed-forward loop at the same time which result in the reduction of NF-κB transcriptional activity and subsequent down-regulation of its target genes.

A synthetic coumarin derivative (4-flourophenylacetamide-acetyl coumarin) impedes cell cycle at G0/G1 stage, induces apoptosis, and inhibits metastasis via ROS-mediated p53 and AKT signaling pathways in A549 cells

New chemotherapeutic agents with minimum side effects are indispensable to treat non-small-cell lung cancer (NSCLC) since the mortality rate of patients suffering from NSCLC remains high despite receiving conventional medication. In our previous study, many coumarin derivatives were screened for their anticancer properties in A549, an in vitro NSCLC model. One of these, 4-flourophenylacetamide-acetyl coumarin (4-FPAC), induced cytotoxicity at a concentration as low as 0.16 nM. Herein, initially, the cytotoxic potential of 4-FPAC was tested on a noncancerous cell line NIH3T3 and was found safe at the selected dose of 0.16 nM. Further, we investigated the mechanism by which 4-FPAC induced cytotoxicity and arrested the progression of cell cycle as well as metastasis in A549. Results of ethidium bromide/acridine orange (EtBr/AO), 4,6-diamidino-2-phenylindole, comet, and lactate dehydrogenase assays revealed that 4-FPAC caused cytotoxicity via reactive oxygen species-induced p53-mediated mechanism, which involves both extrinsic and intrinsic pathways of apoptosis. Dichlorodihydrofluorescein diacetate, rhodamine 123, and AO staining confirmed the involvement of both mitochondria and lysosome in inducing apoptosis. However, flow cytometric analysis revealed that it causes cell cycle arrest at the G0/G1 phase by modulating p21, CDK2, and CDK4 expression. Aggregation, soft-agar, clonogenic, and scratch assays as well as gene expression analysis collectively confirmed that 4-FPAC minimizes the metastatic property of A549 by downregulating Snail, matrix metalloproteinase 9, and interleukin-8. Additional studies reaffirmed the above findings and substantiated the role of PI3K/AKT in achieving them. The cell-type-specific selective cytostatic and antimetastatic properties shown by 4-FPAC indicate its potential to emerge as a drug of choice against NSCLC in the future.

Quinacrine inhibits GSTA1 activity and induces apoptosis through G1/S arrest and generation of ROS in human non-small cell lung cancer cell lines

Background: Quinacrine (QC) is popular for its anti-malarial activity. It has been reported exhibiting anti-cancerous properties by suppressing nuclear factor-κB and activating p53 signaling; however, its effect on cellular pathways in human non-small cell lung cancer (NSCLC) has not been studied.

Materials and Methods: Binding of QC with GSTA1 was studied computationally as well as through GST activity assay kit. Cell viability, cell cycle and mitochondrial membrane potential activity were studied using flow cytometry. RT-PCR and western blot were carried out to understand the involvement of various genes at their mRNA as well as protein level.

Results: QC inhibited the activity of GSTA1 approximately by 40–45% which inhibits cell survival and promotes apoptosis. QC reduced viability of NSCLC cells in a dose-dependent manner. It also causes nuclear fragmentation, G₁/S arrest of cell cycle and ROS generation; which along with disruption of mitochondrial membrane potential activity leads to apoptotic fate.

Conclusions: Results revealed, QC has promising anti-cancer potential against NSCLC cells via inhibition of GSTA1, induction of G₁/S arrest and ROS mediated apoptotic signaling.

Carvacrol Induced Program Cell Death and Cell Cycle Arrest in Androgen-Independent Human Prostate Cancer Cells via Inhibition of Notch Signaling

BACKGROUND

Several studies have revealed that abnormal activation of Notch signaling is closely related with the development and progression of prostate cancer. Although there are numerous therapeutic strategies, a more effective modality with least side effects is urgently required for the treatment of prostate cancer. Carvacrol is a monoterpenoid phenol and majorly present in the essential oils of Lamiaceae family plants. Many previous reports have shown various biological activities of carvacrol like antioxidant, antiinflammatory and anticancer properties. Recently, we have shown potent anticancer property of carvacrol against prostate cancer cell line DU145. In the current study, we report the chemopreventive and therapeutic potential of carvacrol against another prostate cancer cell line PC-3 with its detailed mechanism of action.

METHODS

To determine the effect of the carvacrol on prostate cancer cells, the cell viability was estimated by MTT assay and cell death was estimated by LDH release assay. The apoptotic assay was performed by DAPI staining and FITC-Annexin V assay. Reactive Oxygen Species (ROS) was estimated by DCFDA method. Cell cycle analysis was performed by flow cytometry. Gene expression analysis was performed by quantitative real time PCR.

RESULTS

Our results suggested that the carvacrol treatment significantly reduced the cell viability of PC-3 cells in a dose- and time-dependent manner. The antiproliferative action of carvacrol was correlated with apoptosis which was confirmed by nuclear condensation, FITC-Annexin V assay, modulation in expression of Bax, Bcl-2 and caspase activation. The mechanistic insight into carvacrol-induced apoptosis leads to finding of elevated level of Reactive Oxygen Species (ROS) and mitochondrial membrane potential disruption. Cell cycle analysis revealed that carvacrol prevented cell cycle in G0/G1 that was associated with decline in expression of cyclin D1 and Cyclin-Dependent Kinase 4 (CDK4) and augmented expression of CDK inhibitor p21. Having been said the role of hyperactivation of Notch signaling in prostate cancer, we also deciphered that carvacrol could inhibit Notch signaling in PC-3 cells via downregulation of Notch-1, and Jagged-1.

CONCLUSION

Thus, our previous and current findings have established the strong potential of carvacrol as a chemopreventive agent against androgen-independent human prostate cancer cells.

Leucine Zipper-EF-Hand Containing Transmembrane Protein 1 Is a Potential Prognostic Biomarker and Promotes Cell Progression in Prostate Cancer

Purpose

The leucine zipper-EF-hand containing transmembrane protein 1 (LETM1) is a mitochondrial protein that has been associated with the occurrence and development of malignant tumors. Previous studies have shown that LETM1 expression is increased in several types of human cancer and is associated with a poor clinical outcome. However, the role of LETM1 in prostate cancer (PCa) has not yet been determined. In this study, we investigated the clinicopathological significance of LETM1 expression and its role in PCa progression.

Methods

We assessed the expression of LETM1 and genes related to cancer stemness, epithelial-mesenchymal transition (EMT), cell cycle, and PI3K/Akt signaling in 133 paraffin-embedded PCa tissue samples and cancer cells by using immunohistochemistry, immunofluorescence, and Western blotting.

Results

LETM1 expression was significantly increased in PCa, and it was positively correlated with Gleason score, pathologic tumor (pT) stage, clinical stage, and high microvessel density. Survival analysis showed that patients with PCa with a high level of LETM1 expression exhibited a low overall survival. Cox regression analysis indicated that LETM1 is an independent poor prognostic PCa factor. Additionally, the expression of LETM1 was correlated with cancer cell stemness-associated genes, EMT-related genes, cell cycle regulatory genes, and PI3K/Akt signaling gene expression in PCa. Furthermore, knocking down LETM1 expression down-regulated the expression of stemness-related proteins, while inhibiting tumor spheroid formation, EMT-like changes, cell proliferation, migration, and invasion in PCa cells. Importantly, the PI3K inhibitor LY294002 strongly inhibited the expression of LETM1, pPI3K-p85, and pAkt (Thr308, Ser473) in PCa cells.

Conclusion

These results indicate that LETM1 expression is associated with cancer cell stemness, promotes EMT-like changes and cell proliferation and is a potential prognostic biomarker for PCa.

Expression of Clusterin suppresses Cr(VI)-induced premature senescence through activation of PI3K/AKT pathway

Our group found that long-term low-dose exposure to hexavalent chromium [Cr(VI)] in L-02 hepatocytes resulted in premature senescence, which accompanied by the increased expression of Clusterin (CLU), but the functional role of CLU in premature senescence has never been explored. In the present study, the CLU overexpressed or silenced L-02 hepatocytes were established by lentiviral vector transfection. Cell viability assay, cell cycle analysis, western blotting, plate clone formation assay, and confocal microcopy were performed. The results indicated that Cr(VI)-induced premature senescence was associated with phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway inhibition, and high expression of CLU in the senescent cells exerted its functional role of promoting cell proliferation. CLU could complex with eukaryotic translation initiation factor 3 subunit I (EIF3I) and prevent its degradation, leading to the increase of AKT activity in Cr(VI)-exposed senescent hepatocytes. Blockage of the PI3K/AKT pathway with its inhibitor LY294002 eliminated the inhibitory effect of CLU on Cr(VI)-induced premature senescence. We concluded that high expression of CLU suppressed Cr(VI)-induced premature senescence through activation of PI3K/AKT pathway, which will provide the experimental basis for the study of Cr(VI)-induced liver cancer, especially for the elucidation of the mechanism of liver cancer cells escaping from senescence.

Role of cyclin-dependent kinases (CDKs) in hepatocellular carcinoma: Therapeutic potential of targeting the CDK signaling pathway

Liver cancer is the fourth leading cause of cancer related mortality in the world, with hepatocellular carcinoma (HCC) representing the most common primary subtype. Two-thirds of HCC patients have advanced disease when diagnosed, and for these patients, treatment strategies remain limited. In addition, there is a high incidence of tumor recurrence after surgical resection with the current treatment regimens. The development of novel and more effective agents is required. Cyclin-dependent kinases (CDKs) constitute a family of 21 different protein kinases involved in regulating cell proliferation, apoptosis, and drug resistance, and are evaluated in preclinical and clinical trials as chemotherapeutics. To summarize and discuss the therapeutic potential of targeting CDKs in HCC, recent published articles identified from PubMed were comprehensively reviewed. The key words included hepatocellular carcinoma, cyclin-dependent kinases, and CDK inhibitors. This review focuses on the emerging evidence from studies describing the genetic and functional aspects of CDKs in HCC. We also present an overview of CDK inhibitors that have shown efficacy in laboratory studies of HCC. Although many of the studies assessing CDK-targeting therapies in HCC are at the preclinical stage, there is significant evidence that CDK inhibitors used alone or in combination with established chemotherapy drugs could have significant applications in HCC.

A novel CXCL8 analog is effective in inhibiting the growth via cell cycle arrest and attenuating invasion of Lewis lung carcinoma

Purpose

Lung cancer and other solid tumors contain not only tumor cells but various types of stromal cells, such as fibroblasts and endothelial cells. In addition, tumors are infiltrated by inflammatory cells (neutrophils, macrophages, and lymphocytes). Tumor cells, stromal cells, and the tumor-associated leukocytes are responsible for the production of chemokines inside the tumor and the maintenance of systemic circulating chemokine levels. CXCL8 and its receptors, CXCR1 and CXCR2, were found to play important roles in tumor proliferation, migration, survival, and growth. We have developed a novel ELR-CXC chemokine antagonist CXCL8-IP10 based on the structure of CXCL8 and IP10.

Patients and methods

We assessed the anticancer efficacies of the blockade of CXCL8-CXCR1/2 axis in the Lewis lung carcinoma (LL/2) model using CXCL8-IP10.

Results

We found that CXCL8-IP10 markedly reduced LL/2 cell anchorage-independent growth and invasion. Moreover, we demonstrated that CXCL8-IP10 could significantly suppress tumor growth and improve survival rate as well as lifespan of C57BL/6 mice inoculated with LL/2 cells.

Conclusion

Our results suggest that ELR-CXC chemokine antagonism would potentially be a useful therapeutic approach in patients with lung cancer.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.

MiR-365 enhances the radiosensitivity of non-small cell lung cancer cells through targeting CDC25A

Radioresistance is a major challenge in lung cancer radiotherapy (RT), and consequently, new radiosensitizers are urgently needed. MicroRNAs (miRNAs) have been demonstrated to participate in many important cellular processes including radiosensitization. MiR-365 is dysregulated in non-small cell lung cancer (NSCLC) and is able to restrain the development of NSCLC. However, the relationship between miR-365 and radiosensitivities of NSCLC cells remains largely unknown. Here we reveal that overexpression of miR-365 is able to enhance the radiosensitivity of NSCLC cells through targeting CDC25A. We found that the expression level of miR-365 was positively correlated with the radiosensitivity of NSCLC cell lines. Furthermore, our results showed that overexpression of miR-365 could sensitize A549 cells to the irradiation. However, knockdown of miR-365 in H460 cells could act the converse manner. Mechanically, miR-365 was able to directly target 3'UTR of cell division cycle 25A (CDC25A) mRNA and reduce the expression of CDC25A at the levels of mRNA and protein. And we confirmed that miR-365 could increase the radiosensitivity of NSCLC cells by targeting CDC25A using in vitro and in vivo assays. Taken together, restoration of miR-365 expression enhances the radiosensitivity of NSCLC cells by suppressing CDC25A, and miR-365 could be used as a radiosensitizer for NSCLC therapy.

Anticancer and antimetastatic potential of enterolactone: Clinical, preclinical and mechanistic perspectives

Currently cancer is the second leading cause of death globally and worldwide incidence and mortality rates of all cancers of males and females are rising tremendously. In spite of advances in chemotherapy and radiation, metastasis and recurrence are considered as the major causes of cancer related deaths. Hence there is a mounting need to develop new therapeutic modalities to treat metastasis and recurrence in cancers. A significant amount of substantiation from epidemiological, clinical and laboratory research highlights the importance of diet and nutrition in cancer chemoprevention. Enterolactone (EL) is a bioactive phenolic metabolite known as a mammalian lignan derived from dietary lignans. Here in we review the reported anti-cancer properties of EL at preclinical as well as clinical level. Several in-vivo and in-vitro studies have provided strong evidence that EL exhibits potent anti-cancer and/or protective properties against different cancers including breast, prostate, colo-rectal, lung, ovarian, endometrial, cervical cancers and hepatocellular carcinoma. Reported laboratory studies indicate a clear role for EL in preventing cancer progression at various stages including cancer cell proliferation, survival, angiogenesis, inflammation and metastasis. In clinical settings, EL has been reported to reduce risk, decrease mortality rate and improve overall survival particularly in breast, prostate, colon, gastric and lung cancer. Further, the in-vitro human cell culture studies provide strong evidence of the anticancer and antimetastatic mechanisms of EL in several cancers. This comprehensive review supports an idea of projecting EL as a promising candidate for developing anticancer drug or adjunct dietary supplements and nutraceuticals.

RLIP inhibition suppresses breast-to-lung metastasis

Breast tumor metastasis is a leading cause of cancer-related deaths worldwide. Breast cancer (BC) cells frequently metastasize to the lungs, where they pose a formidable therapeutic challenge. In the current study, we evaluated the anti-proliferative and anti-metastatic effects of 2'-hydroxyflavanone (2HF) and RLIP inhibition in an array of triple-negative BC cell lines and an orthotopic mouse model of breast-to-lung metastasis. Compared to control treatment, RLIP inhibition reduced in-vitro cell viability and suppressed the migratory and invasive potential of BC cells. In-vitro studies showed that 2HF treatment reduced the expression of RLIP, KRAS, pERK, pSTAT3, and pP70S6K. Further, mice orthotopically implanted with lung-seeking luciferase-expressing TMD231 cells were treated with 2HF (50 mg/kg, b.w.), RLIP antisense (RAS; 5 mg/kg, b.w.), RLIP antibody (Rab; 5 mg/kg, b.w.) or a combination of 2HF + RAS + Rab. 2HF-, RAS-, and Rab-treated mice exhibited significantly lower primary tumor weight and reduced lung metastasis compared to control mice. Mice treated with a combination of 2HF + RAS + Rab exhibited no metastasis and significantly lower tumor weight than the single agent-treated mice. Collectively, our results suggest that 2HF has potential to be combined with RLIP inhibition/depletion to more effectively suppress primary breast tumor growth and metastasis to the lungs.

LGM2605 Reduces Space Radiation-Induced NLRP3 Inflammasome Activation and Damage in In Vitro Lung Vascular Networks

Updated measurements of charged particle fluxes during the transit from Earth to Mars as well as on site measurements by Curiosity of Martian surface radiation fluxes identified potential health hazards associated with radiation exposure for human space missions. Designing mitigation strategies of radiation risks to astronauts is critical. We investigated radiation-induced endothelial cell damage and its mitigation by LGM2605, a radioprotector with antioxidant and free radical scavenging properties. We used an in vitro model of lung vascular networks (flow-adapted endothelial cells; FAECs), exposed to gamma rays, low/higher linear energy transfer (LET) protons (3⁻4 or 8⁻10 keV/µm, respectively), and mixed field radiation sources (gamma and protons), given at mission-relevant doses (0.25 gray (Gy)⁻1 Gy). We evaluated endothelial inflammatory phenotype, NLRP3 inflammasome activation, and oxidative cell injury. LGM2605 (100 µM) was added 30 min post radiation exposure and gene expression changes evaluated 24 h later. Radiation induced a robust increase in mRNA levels of antioxidant enzymes post 0.25 Gy and 0.5 Gy gamma radiation, which was significantly decreased by LGM2605. Intercellular cell adhesion molecule-1 (ICAM-1) and NOD-like receptor protein 3 (NLRP3) induction by individual or mixed-field exposures were also significantly blunted by LGM2605. We conclude that LGM2605 is a likely candidate to reduce tissue damage from space-relevant radiation exposure.

Seed coats as an alternative molecular factory: thinking outside the box

Seed coats as commodities. Seed coats play important roles in the protection of the embryo from biological attack and physical damage by the environment as well as dispersion strategies. A significant part of the energy devoted by the mother plant to seed production is channeled into the production of the cell layers and metabolites that surround the embryo. Nevertheless, in crop species these are often discarded post-harvest and are a wasted resource that could be processed to yield co-products. The production of novel compounds from existing metabolites is also a possibility. A number of macromolecules are already accumulated in these maternal layers that could be exploited in industrial applications either directly or via green chemistry, notably flavonoids, lignin, lignan, polysaccharides, lipid polyesters and waxes. Here, we summarize our knowledge of the in planta biosynthesis pathways of these macromolecules and their molecular regulation as well as potential applications. We also outline recent work aimed at providing further tools for increasing yields of existing molecules or the development of novel biotech approaches, as well as trial studies aimed at exploiting this underused resource.

MiR-200a inhibits cell proliferation and EMT by down-regulating the ASPH expression levels and affecting ERK and PI3K/Akt pathways in human hepatoma cells

The primary objective of this study was to investigate the role of miR-200a in cell proliferation and epithelial-mesenchymal transition (EMT) through regulating targeting aspartate-β-hydroxylase (ASPH), which may further affect the activation of ERK/PI3K/Akt pathway. Liver cancer and adjacent tissues were collected from 72 cases of liver cancer patients with surgery in our hospital. In this study, the mRNA expression level of miR-200a was significantly decreased by real-time PCR (RT-PCR) detection. ASPH expressions, however, had an opposite tendency compared to that of miR-200a. We found a significantly negative correlation between miR-200a expressions and ASPH expressions. The survival rate of liver cancer patients with the low expressed ASPH was significantly higher than those with the high expressed ASPH. RT-PCR and Western blot results showed that low expressed miR-200a and highexpressed ASPH were found in liver cancer cell lines. Further research discovered that miR-200a transfection could significantly decrease the relative luciferase activity when it was integrated with ASPH 3'-untranslated region (3'-UTR) in HepG2 cells. Cell Counting Kit (CCK-8) detection showed that treatment with miR-200a mimics reduced cell viability, while the over-expressed ASPH increased cell viability by regulating the c-mycmrna (c-Myc) and Cyclin-D1 expressions. The EMT-related genes including E-Cadherin, N-Cadherin and Vimentin expressions were significantly increased, whereas the over-expressed ASPH exerted the opposite effects. In addition, extracellular signal regulated kinase (ERK), phosphoinositide-3-kinase (PI3K) and serine threonine kinase (AKT) were suppressed by miR-200a mimics. In conclusion, miR-200a inhibits cell proliferation and EMT in human hepatoma cells by targeting ASPH and affecting ERK and PI3K/Akt signaling pathways.

IL‑17 induces NSCLC A549 cell proliferation via the upregulation of HMGA1, resulting in an increased cyclin D1 expression

Non-small cell lung cancer (NSCLC) is considered to be an inflammation-associated carcinoma. Although interleukin‑17 (IL‑17) production contributes to the proliferation and growth of NSCLC, the mechanisms underlying IL‑17-induced NSCLC cell proliferation have not been fully elucidated. In the present study, by using ELISA and immunohistochemical analyses, we first found that the expression levels of IL‑17, IL‑17 receptor (IL‑17R), high-mobility group A1 (HMGA1) and cyclin D1 were elevated in the samples of patients with NSCLC. Subsequently, by RT-qPCR, western blot analysis and cell proliferation assay in vitro, we revealed that stimulation with recombinant human IL‑17 (namely IL‑17A) markedly induced the expression of HMGA1 and cyclin D1 in the A549 cells (a human lung adenocarcinoma cell line) and promoted cell proliferation. Furthermore, luciferase reporter and ChIP assays confirmed that upregulated HMGA1 directly bound to the cyclin D1 gene promoter and activated its transcription. Notably, the response element of HMGA1 binding to the cyclin D1 promoter was disclosed for the first time, at least to the best of our knowledge. Taken together, our findings indicate that the IL‑17/HMGA1/cyclin D1 axis plays an important role in NSCLC cell proliferation and may provide new insight into NSCLC pathogenesis and may thus aid in the development of novel therapeutic targets for NSCLC.

Flaxseed Consumption Inhibits Chemically Induced Lung Tumorigenesis and Modulates Expression of Phase II Enzymes and Inflammatory Cytokines in A/J Mice

Flaxseed consumption is associated with reduced oxidative stress and inflammation in lung injury models and has shown anticancer effects for breast and prostate tissues. However, the chemopreventive potential of flaxseed remains unexplored for lung cancer. In this study, we investigated the effect of flaxseed on tobacco smoke carcinogen (NNK)-induced lung tumorigenesis in an A/J mouse model. Mice exposed to NNK were fed a control diet or a 10% flaxseed-supplemented diet for 26 weeks. Flaxseed-fed mice showed reduced lung tumor incidence (78%) and multiplicity, with an average of 2.7 ± 2.3 surface lung tumor nodules and 1.0 ± 0.9 H&E cross-section nodules per lung compared with the control group, which had 100% tumor incidence and an average of 10.2 ± 5.7 surface lung tumor nodules and 3.9 ± 2.6 H&E cross-section nodules per lung. Furthermore, flaxseed-fed mice had a lower incidence of adenocarcinomas compared with control-fed mice. Western blotting performed on normal lung tissues showed flaxseed suppressed phosphorylation (activation) of p-AKT, p-ERK, and p-JNK kinases. RNA-Seq data obtained from normal lung and lung tumors of control and flaxseed-fed mice suggested that flaxseed intake resulted in differential expression of genes involved in inflammation-mediated cytokine signaling (IL1, 6, 8, 9, and 12α), xenobiotic metabolism (several CYPs, GSTs, and UGTs), and signaling pathways (AKT and MAPK) involved in tumor cell proliferation. Together, our results indicate that dietary flaxseed supplementation may be an effective chemoprevention strategy for chemically induced lung carcinogenesis by altering signaling pathways, inflammation, and oxidative stress. Cancer Prev Res; 11(1); 27-37. ©2017 AACR.

The Synthetic Lignan Secoisolariciresinol Diglucoside Prevents Asbestos-Induced NLRP3 Inflammasome Activation in Murine Macrophages

BACKGROUND

The interaction of asbestos with macrophages drives two key processes that are linked to malignancy: (1) the generation of reactive oxygen species (ROS)/reactive nitrogen species (RNS) and (2) the activation of an inflammation cascade that drives acute and chronic inflammation, with the NLRP3 inflammasome playing a key role. Synthetic secoisolariciresinol diglucoside (SDG), LGM2605, is a nontoxic lignan with anti-inflammatory and antioxidant properties and was evaluated for protection from asbestos in murine peritoneal macrophages (MF).

METHODS

MFs were exposed to crocidolite asbestos ± LGM2605 given 4 hours prior to exposure and evaluated at various times for NLRP3 expression, secretion of inflammasome-activated cytokines (IL-1β and IL-18), proinflammatory cytokines (IL-6, TNFα, and HMGB1), NF-κB activation, and levels of total nitrates/nitrites.

RESULTS

Asbestos induces a significant (p < 0.0001) increase in the NLRP3 subunit, release of proinflammatory cytokines, NLRP3-activated cytokines, NF-κB, and levels of nitrates/nitrites. LGM2605 significantly reduced NLRP3 ranging from 40 to 81%, IL-1β by 89-96%, and TNFα by 67-78%, as well as activated NF-κB by 48-49% while decreasing levels of nitrates/nitrites by 85-93%.

CONCLUSIONS

LGM2605 reduced asbestos-induced NLRP3 expression, proinflammatory cytokine release, NF-κB activation, and nitrosative stress in MFs supporting its possible use in preventing the asbestos-induced inflammatory cascade leading to malignancy.