Taiwanin E inhibits cell migration in human LoVo colon cancer cells by suppressing MMP-2/9 expression via p38 MAPK pathway

Genome-wide DNA methylation regulation analysis provides novel insights on post-radiation breast cancer

Breast cancer (BC) is the most common malignancy with a poor prognosis. Radiotherapy is one of the leading traditional treatments for BC. However, radiotherapy-associated secondary diseases are severe issues for the treatment of BC. The present study integrated multi-omics data to investigate the molecular and epigenetic mechanisms involved in post-radiation BC. The differences in the expression of radiation-associated genes between post-radiation and pre-radiation BC samples were determined. Enrichment analysis revealed that these radiation-associated genes involved diverse biological functions and pathways in BC. Combining epigenetic data, we identified radiation-associated genes whose transcriptional changes might be associated with aberrant methylation. Then, we identified potential therapeutic targets and chemical drugs for post-radiation BC patient treatment by constructing a drug-target association network. Specifically, four radiation-associated genes (CD248, CCDC80, GADD45B, and MMP2) whose increased expression might be regulated by hypomethylation of the corresponding enhancer region were found to have excellent diagnostic effects and clinical prognostic value. Finally, we further used independent samples to verify CD248 expression and established a simple epigenetic regulatory model. In summary, this study provides novel insights for understanding the regulation of target genes mediated by DNA methylation and developing potential biomarkers for radiation-associated secondary diseases in BC.

MMP9: Link between neuropathy and colorectal cancer?

As chemotherapy is still a cornerstone of colorectal cancer (CRC) treatment, chemotherapy-induced peripheral neuropathy (CIPN) presents significant clinical challenges, affecting millions worldwide. A subset of colon cancer patients (approximately 30%) develop chronic CIPN, with detrimental, untreatable neuropathic pain symptoms. The risk factors of such intractable chronic CIPN are unknown. However, there is growing literature data investigating the intriguing interplay of neurons and cancer (cancer neuroscience). Recent data shows that this interplay might have a key role in the development and severity of CIPN. Given its vast (patho)physiological roles in both colon cancer and neuropathy, MMP9 seems to be a key factor that might drive the development of neuronal damage in colon cancer patients. This review investigates the role of matrix metalloproteinase 9 (MMP9) in linking CRC to neuropathy, aiming to uncover shared mechanisms that could offer new therapeutic targets. By synthesizing insights from a broad range of studies published over the last 20 years, we explore MMP9's involvement in CRC progression, its role in CIPN, and the interconnected pathways influencing both conditions. These studies reveal MMP9 as a pivotal mediator in ECM remodeling, inflammation, and signal transduction pathways, emphasizing its modulation by macrophages. These shared mechanisms of colon cancer and CIPN pathophysiology suggest MMP9's potential contribution to neuropathic conditions in CRC patients, positioning it as a critical factor in disease progression and a promising therapeutic target. Future research should focus on longitudinal studies to assess MMP9's impact on neuropathy outcomes in CRC patients, exploring MMP9 inhibitors, and developing targeted interventions to mitigate the detrimental symptoms of CIPN. MMP9 also seems to be a feasible driving factor in the development of chronic CIPN in colon cancer patients.

EtROP38 suppresses apoptosis of host cells infected with Eimeria tenella by inhibition of the p38MAPK pathway

Coccidiosis is an important parasitic disease that has serious adverse effects on the global poultry industry. The mechanism by which the pathogenic factors of Eimeria tenella damage host cells is unknown. Some kinases from the rhoptry compartment can regulate apoptosis of host cells. This study focused on revealing the role and critical nodes of E. tenella rhoptry protein (EtROP) 38 in controlling the apoptosis of host cells via the P38 mitogen-activated protein kinase (MAPK) signaling pathway. The cells were treated with EtROP38 protein, siRNA p38MAPK, or both. The rate of infection, apoptosis, and the dynamic changes in the expression and activation of key factor genes of the P38MAPK signaling pathway in host cells infected with E. tenella were measured. The results showed that the addition of EtROP38 and/or knockdown of the host cells p38 gene reduced the apoptosis rate of cecal epithelial cells (CECS), decreased the mRNA expressions of p38, p53, c-myc, c-fos, and c-jun and increased the expression of p65, decreased the protein expressions of c-myc, c-fos, and c-jun, decreased the p38 protein phosphorylation level, and increased the p65 protein phosphorylation level in CECS. When E. tenella was inoculated for 4-96 h, the addition of Et ROP38 and/or host cell p38 knockdown both increased the infection rate of host cells, and this effect was more pronounced with the addition of EtROP38 with the host cell p38 knockdown. These observations indicate that E. tenella can inhibits the activation of the p38MAPK signaling pathway in host cells via EtROP38, which suppresses apoptosis in host cells.

Prediction of Rab5B inhibitors through integrative in silico techniques

Rab5B is a small monomeric G protein that regulates early endocytosis and controls signaling pathways related to cell growth, survival, and apoptosis. Dysregulation of Rab5B protein expression has been linked to the development of several cancers such as leukemia, lymphoma, kidney, prostate, ovarian, breast cancer, etc. Our research shows the first attempt to identify inhibitors that can target Rab5B GTPase. In this study, we performed molecular docking using Autodock Vina 1.5.6 and identified eight molecules with docking scores ranging from -9.8 to -10.6 kcal/mol. Thereafter, we examined the pharmacological characteristics of these compounds, and selected compounds were further analyzed for their conformational dynamics and thermodynamic stability using molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA)-based free energy calculations. Notably, our findings revealed that strychnine had the highest binding affinity to Rab5B followed by anonaine, helioxanthin, and taiwanin E, with a ΔGbind value of -21.43, -17.11, -15.11, and -14.09 kcal/mol respectively. The binding free energy calculations showed that Van der Waals interactions are the primary contributor to the binding between Rab5B and the inhibitor. The interaction between the inhibitor and Rab5B was shown to be controlled by certain hot spot residues, including Phe45, Tyr48, Ala64, and Ala30. Overall, we believe that these findings could facilitate the exploration and development of potential hits against Rab5B, subject to optimization and further research.

Phytochemistry and Pharmacology of Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y.Hu: A Review

Eleutherococcus sessiliflorus (Rupr. & Maxim.) S.Y.Hu (E. sessiliflorus), a member of the Araliaceae family, is a valuable plant widely used for medicinal and dietary purposes. The tender shoots of E. sessiliflorus are commonly consumed as a staple wild vegetable. The fruits of E. sessiliflorus, known for their rich flavor, play a crucial role in the production of beverages and fruit wines. The root barks of E. sessiliflorus are renowned for their therapeutic effects, including dispelling wind and dampness, strengthening tendons and bones, promoting blood circulation, and removing stasis. To compile a comprehensive collection of information on E. sessiliflorus, extensive searches were conducted in databases such as Web of Science, PubMed, ProQuest, and CNKI. This review aims to provide a detailed exposition of E. sessiliflorus from various perspectives, including phytochemistry and pharmacological effects, to lay a solid foundation for further investigations into its potential uses. Moreover, this review aims to introduce innovative ideas for the rational utilization of E. sessiliflorus resources and the efficient development of related products. To date, a total of 314 compounds have been isolated and identified from E. sessiliflorus, encompassing terpenoids, phenylpropanoids, flavonoids, volatile oils, organic acids and their esters, nitrogenous compounds, quinones, phenolics, and carbohydrates. Among these, triterpenoids and phenylpropanoids are the primary bioactive components, with E. sessiliflorus containing unique 3,4-seco-lupane triterpenoids. These compounds have demonstrated promising properties such as anti-oxidative stress, anti-aging, antiplatelet aggregation, and antitumor effects. Additionally, they show potential in improving glucose metabolism, cardiovascular systems, and immune systems. Despite some existing basic research on E. sessiliflorus, further investigations are required to enhance our understanding of its mechanisms of action, quality assessment, and formulation studies. A more comprehensive investigation into E. sessiliflorus is warranted to delve deeper into its mechanisms of action and potentially expand its pharmaceutical resources, thus facilitating its development and utilization.

Rh(III)-Catalyzed C-H Annulation of Sulfoxonium Ylides and 1,3-Diynes: A Rapid Access to Alkynyl-1-Naphthol Derivatives

An effective redox-neutral strategy to synthesize aryl/alkynyl and alkyl/alkynyl substituted 1-naphthol derivatives has been efficaciously developed by Rh(III)-catalyzed [4+2]-annulation of sulfoxonium ylides and 1,3-diynes with excellent regio- and chemoselectivity. Subsequently, the same strategy was extended to furnish various unsymmetrical binaphthol motifs in one-pot manner. Interestingly, the TMS-derived 1,3-diyne predominantly delivered the 3-alkynyl-1-naphthol via desilylation pathway. The salient features such as traceless directing group, broad substrate scope, good functional group tolerance, and operationally simple conditions made the present protocol more valuable and appealing.

Amaryllidaceae Alkaloids Decrease the Proliferation, Invasion, and Secretion of Clinically Relevant Cytokines by Cultured Human Colon Cancer Cells

Alkaloids isolated from members of the Amaryllidaceae plant family are promising anticancer agents. The purpose of the current study was to determine if the isocarbostyrils narciclasine, pancratistatin, lycorane, lycorine, crinane, and haemanthamine inhibit phenomena related to cancer progression in vitro. To achieve this, we examined the proliferation, adhesion, and invasion of cultured human colon cancer cells via MTT assay and Matrigel-coated Boyden chambers. In addition, Luminex assays were used to quantify the secretion of matrix metalloproteinases (MMP) and cytokines associated with poor clinical outcomes. We found that all alkaloids decreased cell proliferation regardless of TP53 status, with narciclasine exhibiting the greatest potency. The effects on cell proliferation also appear to be specific to cancer cells. Narciclasine, lycorine, and haemanthamine decrease both adhesion and invasion but with various potencies depending on the cell line. In addition, narciclasine, lycorine, and haemanthamine decreased the secretion of MMP-1, -2, and -7, as well as the secretion of the cytokines pentraxin 3 and vascular endothelial growth factor. In conclusion, the present study shows that Amaryllidaceae alkaloids decrease phenomena and cytokines associated with colorectal cancer progression, supporting future investigations regarding their potential as multifaceted drug candidates.

Inhibition and potential treatment of colorectal cancer by natural compounds via various signaling pathways

Colorectal cancer (CRC) is a common type of malignant digestive tract tumor with a high incidence rate worldwide. Currently, the clinical treatment of CRC predominantly include surgical resection, postoperative chemotherapy, and radiotherapy. However, these treatments contain severe limitations such as drug side effects, the risk of recurrence and drug resistance. Some natural compounds found in plants, fungi, marine animals, and bacteria have been shown to inhibit the occurrence and development of CRC. Although the explicit molecular mechanisms underlying the therapeutic effects of these compounds on CRC are not clear, classical signaling transduction pathways such as NF-kB and Wnt/β-catenin are extensively regulated. In this review, we have summarized the specific mechanisms regulating the inhibition and development of CRC by various types of natural compounds through nine signaling pathways, and explored the potential therapeutic values of these natural compounds in the clinical treatment of CRC.

A world tour in the name of natural products

BACKGROUND

Names of natural products (NP) are usually given depending on the species of origin, be it a plant, a marine organism or a microbial species. In some cases, names have been given with reference to people, animals, music, foods or places. Many NP refer to countries, cities or specific places such as mountains, deserts, seas and oceans.

PURPOSE

On the basis of NP names, a world tour has been imagined referring to more than one hundred NP with names evocative of over 50 countries and regions.

RESULTS

The world tour goes from UK (britannin) to Italy (vaticanol) in Europe, from Uganda (ugandoside) to Senegal (senegalene, senegalenines) in Africa, from Brazil (brasilin) to Chile (santiaguine) in South America, from Utah (utahin) to Florida (floridanolide) in the US. It includes Central America (mexicanin, panamine) and the Caribbean islands (jamaicin, bahamaolides). It also crosses Alaska (alaskene) and Canada (quebecol, canadaline). The tour continues throughout Asia, from Thailand (thailandine) to China (Chinaldine) and Pakistan (pakistanamine), to finally reaches Oceania with Australia (australigenin) and Vanuatu (vanuatine), among other countries. This virtual journey, without bordure or wall, brings us to the highest mountains (himalayamine), the deepest oceans (pacificins) and the largest deserts (desertomycin).

CONCLUSION

In the current period of COVID-19 pandemia, with restricted opportunities for international travels, this NP name-based virtual journey offers a world tour to learn more from nature and to inspire scientists to contribute to the field of NP discovery and drug design. There are also limitations associated with the use of trivial names for NP. NP names can be further exploited for teaching and learning.

Cytotoxicity and Apoptosis Induction of 6,7-Dehydroroyleanone from Taiwania cryptomerioides Bark Essential Oil in Hepatocellular Carcinoma Cells

The objective of the present study is to evaluate the cytotoxicity of Taiwania cryptomerioides essential oil and its phytochemical on the Hep G2 cell line (human hepatocellular carcinoma). Bark essential oil has significant cytotoxicity to Hep G2 cells, and S3 fraction is the most active fraction in cytotoxicity to Hep G2 cells among the six fractions. The diterpenoid quinone, 6,7-dehydroroyleanone, was isolated from the active S3 fraction by bioassay-guided isolation. 6,7-Dehydroroyleanone exhibited significant cytotoxicity in Hep G2 cells, and the efficacy of 6,7-dehydroroyleanone was better than the positive control, etoposide. Apoptosis analysis of Hep G2 cells with different treatments was characterized via flow cytometry to confirm the cell death situation. Etoposide and 6,7-dehydroroyleanone could induce the apoptosis in Hep G2 cells using flow cytometric assay. Results revealed 6,7-dehydroroyleanone from T. cryptomerioides bark essential oil can be a potential phytochemical to develop the anticancer chemotherapeutic agent for the treatment of the human hepatocellular carcinoma.

Synthesis and biological evaluation of some 1-naphthol derivatives as antioxidants, acetylcholinesterase, and carbonic anhydrase inhibitors

A series of some naphthol derivatives 4a-f, 5a,f, 6a, and 7a,b (six novel ones: 4c,d, 5a, 6a, 7a,b) bearing F, Cl, Br, OMe, and dioxole substituents at different positions of the aromatic rings was designed, synthesized, and characterized. The naphthol derivatives were synthesized in three steps, namely the addition reaction of furan via Diels-Alder cycloaddition reaction, copper(II) trifluoromethanesulfonate (Cu(OTf)₂ )-catalyzed aromatization reaction, and the bromination reaction, respectively. The structures of the newly obtained compounds (4c,d, 5a, 6a, 7a,b) were characterized by spectroscopic techniques. In addition, some biological activity studies were investigated under in vitro conditions. Inhibition studies of these compounds were performed on human carbonic anhydrase (hCA) I and II isoenzymes purified from human erythrocytes as a biological evaluation. Moreover, their potential antioxidant and antiradical activities were studied by analytical methods like ABTS^•+ and DPPH• scavenging, and it was determined that some molecules showed good activity. Also, inhibition of acetylcholinesterase (AChE), which is a marker of many degenerative neurological diseases, was tested and the results were discussed. Excellent enzyme inhibition results were recorded for most of the molecules. These 1-naphthol derivatives were found as effective inhibitors for hCA I, hCA II, and AChE with K _i values ranging from 0.034 ± 0.54 to 0.724 ± 0.18 µM for hCA I, 0.172 ± 0.02 to 0.562 ± 0.21 µM for hCA II, and 0.096 ± 0.01 to 0.177 ± 0.02 µM for AChE.

Exploring the dermotoxicity of the mycotoxin deoxynivalenol: combined morphologic and proteomic profiling of human epidermal cells reveals alteration of lipid biosynthesis machinery and membrane structural integrity relevant for skin barrier function

Deoxynivalenol (vomitoxin, DON) is a secondary metabolite produced by Fusarium spp. fungi and it is one of the most prevalent mycotoxins worldwide. Crop infestation results not only in food and feed contamination, but also in direct dermal exposure, especially during harvest and food processing. To investigate the potential dermotoxicity of DON, epidermoid squamous cell carcinoma cells A431 were compared to primary human neonatal keratinocytes (HEKn) cells via proteome/phosphoproteome profiling. In A431 cells, 10 µM DON significantly down-regulated ribosomal proteins, as well as mitochondrial respiratory chain elements (OXPHOS regulation) and transport proteins (TOMM22; TOMM40; TOMM70A). Mitochondrial impairment was reflected in altered metabolic competence, apparently combined with interference of the lipid biosynthesis machinery. Functional effects on the cell membrane were confirmed by live cell imaging and membrane fluidity assays (0.1–10 µM DON). Moreover, a common denominator for both A431 and HEKn cells was a significant downregulation of the squalene synthase (FDFT1). In sum, proteome alterations could be traced back to the transcription factor Klf4, a crucial regulator of skin barrier function. Overall, these results describe decisive molecular events sustaining the capability of DON to impair skin barrier function. Proteome data generated in the study are fully accessible via ProteomeXchange with the accession numbers PXD011474 and PXD013613.

Anti-Tumor Mechanisms Associated With Regulation of Non-Coding RNA by Active Ingredients of Chinese Medicine: A Review

Cancer has become the second leading cause of death worldwide; however, its complex pathogenesis remains largely unclear. Previous research has shown that cancer development and progression are closely associated with various non-coding RNAs, including long non-coding RNAs and microRNAs, which regulate gene expression. Target gene abnormalities are regulated and engaged in the complex mechanism underlying tumor formation, thereby controlling apoptosis, invasion, and migration of tumor cells and providing potentially effective targets for the treatment of malignant tumors. Chemotherapy is a commonly used therapeutic strategy for cancer; however, its effectiveness is limited by general toxicity and tumor cell drug resistance. Therefore, increasing attention has been paid to developing new cancer treatment modalities using traditional Chinese medicines, which exert regulatory effects on multiple components, targets, and pathways. Several active ingredients in Chinese medicine, including ginsenoside, baicalin, and matrine have been found to regulate ncRNA expression levels, thus, exerting anti-tumor effects. This review summarizes the scientific progress made regarding the anti-tumor mechanisms elicited by various active ingredients of Chinese medicine in regulating non-coding RNAs, to provide a theoretical foundation for treating tumors using traditional Chinese medicine.

Platycodin D reverses histone deacetylase inhibitor resistance in hepatocellular carcinoma cells by repressing ERK1/2-mediated cofilin-1 phosphorylation

BACKGROUND

Chemoresistance remains the main obstacle in hepatocellular carcinoma (HCC) therapy. Despite significant advances in HCC therapy, HCC still has a poor prognosis. Thus, there is an urgent need to identify a treatment target to reverse HCC chemotherapy resistance. Platycodon grandiflorus (PG) is a perennial herb that has been used as food and traditional Chinese medicine for thousands of years in Northeast Asia. Platycodin D (PD), a main active triterpenoid saponin found in the root of PG, has been reported to possess anticancer properties in several cancer cell lines, including HCC; however, the reversal effect of this molecule on HCC chemoresistance remains largely unknown.

PURPOSE

This study aimed to investigate the role and the mechanism of PD-mediated reversal of the histone deacetylase inhibitor (HDACi) resistance in HCC cells.

METHODS

Human HCC cells (HA22T) and HDACi-resistant (HDACi-R) cells were used. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Combination index was used to calculate the synergism potential. Expression of ERK1/2 (total/phospho), cofilin-1 (total/phospho) and apoptosis-related protein was determined using western blotting. Mitochondrial membrane potential was assessed using the JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide) probe. Apoptosis was detected using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Mitochondrial reactive oxygen species generation was measured using the MitoSOX Red fluorescent probe.

RESULTS

We found that PD treatment inhibited cell viability both in HA22T HCC and HDACi-R cells. Inhibition of ERK1/2 by PD98059 could reverse drug resistance in HDACi-R cells treated with PD98059 and PD. Nevertheless, pre-treatment with U46619, an ERK1/2 activator, rescued PD-induced apoptosis by decreasing levels of apoptosis-related proteins in HCC cells. The combined treatment of PD with apicidin a powerful HDACi, dramatically enhanced the apoptotic effect in HDACi-R cells.

CONCLUSION

For the first time, we showed that PD reversed HDACi resistance in HCC by repressing ERK1/2-mediated cofilin-1 phosphorylation. Thus, PD can potentially be a treatment target to reverse HCC chemotherapy resistance in future therapeutic trials.

Hsa_Circ_0007843 Acts as a mIR-518c-5p Sponge to Regulate the Migration and Invasion of Colon Cancer SW480 Cells

Circular RNA (circRNA), a type of RNA that is widely expressed in mammalian cells, is considered to be essential in tumorigenesis. CircRNA can regulate target gene expression by interacting with the corresponding microRNA (miRNA). Our preliminary results showed that the expression levels of 1,817 circRNAs were significantly different in colon cancer tissue compared with paracancerous tissue, of which 1,236 were upregulated and 581 were downregulated. By using RT-PCR, we confirmed that the expression of hsa_circ_0007843, hsa_circ_0010575, hsa_circ_0007331, and hsa_circ_0001615 was significantly higher in colon cancer tissue than in normal colonic tissue; however, the expression levels of hsa_circ_0014879 and hsa_circRNA_401801 were not significantly different between normal and neoplastic colonic tissue. Among the circRNAs that were confirmed to be upregulated in colon cancer tissue, hsa_circ_0007843 was also found to be highly expressed in colon cancer SW480 cells. Overexpression of hsa_circ_0007843 promoted the invasion and migration of SW480 cells, whereas its downregulation suppressed their invasion and migration. Overexpression of hsa_circ_0007843 promoted tumor growth, whereas its downregulation inhibited tumor growth. We found that hsa_circ_0007843 interacted with miR-518c-5p and suppressed its expression, and miR-518c-5p interacted with matrix metallopeptidase 2 (MMP2) and promoted its expression and translation. Taken together, this study demonstrated that hsa_circ_0007843 acted as an miRNA sponge to regulate MMP2 expression by removing the inhibitory effect of miR-518c-5p on MMP2 gene translation, which further affected the invasive capability of SW480 cells.

Taiwanin E Induces Cell Cycle Arrest and Apoptosis in Arecoline/4-NQO-Induced Oral Cancer Cells Through Modulation of the ERK Signaling Pathway

Taiwanin E is a bioactive compound extracted from Taiwania cryptomerioides Hayata. In this research endeavor, we studied the anti-cancer effect of Taiwanin E against arecoline and 4-nitroquinoline-1-oxide-induced oral squamous cancer cells (OSCC), and elucidated the underlying intricacies. OSCC were treated with Taiwanin E and analyzed through MTT assay, Flow cytometry, TUNEL assay, and Western blotting for their efficacy against OSCC. Interestingly, it was found that Taiwanin E significantly attenuated the cell viability of oral cancer cells (T28); however, no significant cytotoxic effects were found for normal oral cells (N28). Further, Flow cytometry analysis showed that Taiwanin E induced G1cell cycle arrest in T28 oral cancer cells and Western blot analysis suggested that Taiwanin E considerably downregulated cell cycle regulatory proteins and activated p53, p21, and p27 proteins. Further, TUNEL and Western blot studies instigated that it induced cellular apoptosis and attenuated the p-PI3K/p-Akt survival mechanism in T28 oral cancer cells seemingly through modulation of the ERK signaling cascade. Collectively, the present study highlights the prospective therapeutic efficacy of Taiwanin E against arecoline and 4-nitroquinoline-1-oxide-induced oral cancer.

Inhibition of protein phosphatase 1 stimulates noncanonical ER stress eIF2α activation to enhance fisetin-induced chemosensitivity in HDAC inhibitor-resistant hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is a common fatal type of malignant tumor that has highly metastatic and recurrent properties. Fisetin is a natural flavonoid found in various vegetables and fruits which exhibits anti-cancer and anti-inflammatory properties, as well as other effects. Thus, we hypothesized that fisetin can act as an adjuvant therapy in cancer or drug-resistant cancer cells, and further investigated the molecular mechanisms underlying the development of drug-resistance in HCC cells. We found that fisetin effectively inhibited the cell viability of not only parental cells but also histone deacetylase inhibitors-resistant (HDACis-R) cells and enhanced the chemosensitivity of HCC cells. Interestingly, fisetin did not induce cell apoptosis through the activation of the endoplasmic reticulum (ER) stress sensor of protein kinase R (PKR)-like endoplasmic reticulum kinase, but rather through the non-canonical pathway of the protein phosphatase 1 (PP1)-mediated suppression of eIF2α phosphorylation. Moreover, fisetin-induced cell apoptosis was reversed by treatment with PP1 activator or eIF2α siRNA in HCC cells. Based on these observations, we suggest that PP1-eIF2α pathways are significantly involved in the effect of fisetin on HCC apoptosis. Thus, fisetin may act as a novel anticancer drug and new chemotherapy adjuvant which can improve the efficacy of chemotherapeutic agents and diminish their side-effects.

Upregulation of HRD1 promotes cell migration and invasion in colon cancer

3-Hydroxy-3-methylglutaryl reductase degradation (HRD1) is an E3 ubiquitin ligase that functions by promoting degradation of misfolded proteins in processes such as embryogenesis and rheumatoid arthritis. However, little is known about the role of HRD1 in cancer. The aim of the present study was to investigate the expression pattern and functions of HRD1 in human colon cancer (CC). We found that HRD1 expression was increased significantly in human CC tissues, and its overexpression was associated with TNM stage, tumor differentiation, tumor invasive depth, and distant metastasis. Knockdown of HRD1 using small hairpin (sh) RNA plasmid significantly inhibited CC cell migration and invasion. Furthermore, the silencing of HRD1 decreased the expression of MMP-2 and MMP-9, which is critical for CC cell migration and invasion. Taken together, these results revealed that HRD1 is overexpressed in CC and promotes migration and invasion of CC cells. Inhibition of HRD1 may be considered as an effective anti-CC strategy.

Melatonin inhibits colon cancer RKO cell migration by downregulating Rho‑associated protein kinase expression via the p38/MAPK signaling pathway

Melatonin is predominately produced and secreted by the pineal gland, and inhibits cell growth in various cancer cell lines such as colorectal cancer. However, the precise mechanisms involved have not been fully elucidated. In the present study, the potential molecular mechanism underlying the efficacy of melatonin on migration in RKO colon cancer cells was investigated. The effects of melatonin and H-1152, a selective inhibitor of Rho-associated protein kinase (ROCK), on the migration of RKO cells were analyzed by an in vitro wound healing assay. The localization of zonula occludens-1 (ZO-1) and occludin were observed by immunofluorescence. Reverse transcription-quantitative polymerase chain reaction (qPCR) was performed to analyze the relative mRNA levels of ROCK, ZO-1 and occludin. In addition, western blot analysis was implemented to examine the expression of ROCK, phospho (p)-myosin phosphatase targeting subunit 1 (MYPT1), p-myosin light chains (MLC) and p-p38. The results revealed that the expression levels of ROCK2, p-MYPT1 and p-MLC in RKO cells were decreased, and the membrane protein expression of ZO-1 and occludin increased when the cells were treated with melatonin. qPCR demonstrated that melatonin downregulated ROCK2 gene expression, and upregulated the expression of the ZO-1 and occludin genes. The levels of ZO-1 and occludin localized in the tight junctions were markedly increased in the immunofluorescence assay. In addition, the phosphorylation levels of p38 were reduced when the cells were treated with melatonin, and treatment with H-1152 downregulated p38 phosphorylation. The results indicated that melatonin may inhibit the migration of RKO colon cancer cells by downregulating ROCK expression via the p38/mitogen-activated protein kinase signaling pathway.