1,3-Bis(2-chloroethyl)-1-nitrosourea enhances the inhibitory effect of Resveratrol on 5-fluorouracil sensitive/resistant colon cancer cells

Resveratrol: Targeting Cancer Stem Cells and ncRNAs to Overcome Cancer Drug Resistance

A major challenge in treating cancer is the development of drug resistance, which can result in treatment failure and tumor recurrence. Targeting cancer stem cells (CSCs) and non-coding RNAs (ncRNAs) with a polyphenolic substance called resveratrol has the ability to combat this problem by lowering cancer resistance to drugs and opening up new therapeutic options. Resveratrol alters the expression of genes related to self-renewal, modulating important signaling pathways involved in cancer initiation and CSC control. Additionally, resveratrol affects non-coding RNAs (ncRNAs), including Micro-RNAs (miRNAs) and long non-coding RNAs (lncRNAs which are essential for stemness, drug resistance, and other cancer-related activities. Numerous studies have shown that resveratrol has the potential to be an effective anticancer drug when used in combination therapy, but issues with absorption and pharmacokinetics still need to be resolved before it can be used in clinical applications. Reducing chemotherapy resistance by better understanding the intricate mechanisms by which resveratrol affects cancer cells and CSCs, as well as its impact on ncRNA expression, could eventually contribute to more effective cancer treatments. To completely understand these pathways and optimize the utilization of resveratrol in combination treatments, additional study is necessary.

Regulation of thymidylate synthase: an approach to overcome 5-FU resistance in colorectal cancer

Thymidylate synthase is the rate-limiting enzyme required for DNA synthesis and overexpression of this enzyme causes resistance to cancer cells. Long treatments with 5-FU cause resistance to Thymidylate synthase targeting drugs. We have also compiled different mechanisms of drug resistance including autophagy and apoptosis, drug detoxification and ABC transporters, drug efflux, signaling pathways (AKT/PI3K, RAS-MAPK, WNT/β catenin, mTOR, NFKB, and Notch1 and FOXM1) and different genes associated with resistance in colorectal cancer. We can overcome 5-FU resistance in cancer cells by regulating thymidylate synthase by natural products (Coptidis rhizoma), HDAC inhibitors, mTOR inhibitors, Folate antagonists, and several other drugs which have been used in combination with TS inhibitors. This review is a compilation of different approaches reported for the regulation of thymidylate synthase to overcome resistance in colorectal cancer cells.

Protective role of Codiaeum variegatum against genotoxicity induced by carmustine in somatic and germ cells of male mice

Background

Carmustine (Cr) is an important chemotherapeutic drug, widely used in the treatment of brain tumors. Herein, the protective role of Codiaeum variegatum leaves ethyl acetate fraction was determined against genotoxicity of Cr. The technique HPLC-qTOF-MS/MS was used to identify the constituents in C. variegatum.

Materials

90 male mice were used to evaluate micronuclei (MPCEs) in bone marrow, chromosomal aberration (CAs) in bone marrow and mouse spermatocytes, sperm abnormalities, and gene expression (qRT-PCR). The following groups were included, I: Negative control (ethanol 30%), II: Positive control (i.p injected once with 30 mg/kg Cr), III: Control orally treated with C. variegatum at 500 mg/kg, four days. IV-VI: treated with 100, 300, and 500 mg/kg of the plant (4 days) plus a single dose of Cr.

Results

In bone marrow, Cr induced significant increase in MPCEs and CAs by 3 and 7-folds respectively over the control. Cr also induced a significant percentage of CAs in spermatocytes in meiosis in the form of univalent (X–Y and autosomal univalent) and also a significant percentage of morphological sperm abnormalities was recorded. A large number of coiled tail abnormalities were detected indicating the effect of Cr in sperm motility. Cr induced an overexpression of p53 gene. C. variegatum mitigated all deleterious genotoxic effects of Cr. Chemical analysis showed that flavones (35.21%) and phenolic acids (17.62%) constitute the main components.

Conclusions

The results indicated that Cr is genotoxic in both somatic and germ cells. The active components in C. variegatum together participate in the obtained protective role.

Identification of prognostic stemness biomarkers in colon adenocarcinoma drug resistance

BACKGROUND

Colon adenocarcinoma (COAD) is one of the leading causes of death worldwide. Cancer stem cells (CSCs) are vital for COAD chemoresistance and recurrence, however little is known about stem cell-related biomarkers in drug resistance and COAD prognosis prediction.

METHODS

To uncover the roles of CSC in COAD tumorigenesis, chemoresistance, and prognosis, we retrieved COAD patients' RNAseq data from TCGA (The Cancer Genome Atlas). We further performed analysis of differentially expressed genes (DEGs) and mRNA expression-based stemness index (mRNAsi) to identify stemness-related COAD biomarkers. We then evaluated the roles of mRNAsi in tumorigenesis, clinical-stage, overall survival (OS), and chemoresistance. Afterward, we used identified prognostic stemness-related genes (PSRGs) to construct a prediction model. After constructing the prediction model, we used elastic Net regression and area under the curve (AUC) to explore the prediction value of PSRGs based on risk scores and the receiver operator characteristic (ROC) curve. To elucidate the underlying interconnected systems, we examined relationships between the levels of TFs, PSRGs, and 50 cancer hallmarks by a Pearson correlation analysis.

RESULTS

Twelve thousand one hundred eight DEGs were identified by comparing 456 primary COADs and 41 normal solid tissue samples. Furthermore, we identified 4351 clinical stage-related DEGs, 16,516 stemness-associated DEGs, and 54 chemoresistance-related DEGs from cancer stages: mRNAsi, and COAD chemoresistance. Compared to normal tissue samples, mRNAsi in COAD patients were marked on an elevation and involved in prognosis (p = 0.027), stemness-related DEGs based on chemoresistance (OR = 3.28, p ≤ 0.001) and AJCC clinical stage relating (OR = 4.02, p ≤ 0.001) to COAD patients. The prediction model of prognosis were constructed using the 6 PSRGs with high accuracy (AUC: 0.659). The model identified universal correlation between NRIP2 and FDFT1 (key PRSGs), and some cancer related transcription factors (TFs) and trademarks of cancer gene were in the regulatory network.

CONCLUSION

We found that mRNAsi is a reliable predictive biomarker of tumorigenesis and COAD prognosis. Our established prediction model of COAD chemoresistance, which includes the six PSRGs, is effective, as the model provides promising therapeutic targets in the COAD.

Applications of resveratrol in the treatment of gastrointestinal cancer

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

Molecular Basis of Resveratrol-Induced Resensitization of Acquired Drug-Resistant Cancer Cells

Multidrug resistance (MDR) to anticancer drugs remains a serious obstacle to the success of cancer chemotherapy. Resveratrol, a polyphenol, present in natural products exerts anticancer activity and acts as a potential MDR inhibitor in various drug-resistant cancer cells. In the process of resensitization of drug-resistant cancer cells, resveratrol has been shown to interfere with ABC transporters and drug-metabolizing enzymes, increase DNA damage, inhibit cell cycle progression, and induce apoptosis and autophagy, as well as prevent the induction of epithelial to mesenchymal transition (EMT) and cancer stem cells (CSCs). This review summarizes the mechanisms by which resveratrol counteracts MDR in acquired drug-resistant cancer cell lines and provides a critical basis for understanding the regulation of MDR as well as the development of MDR-inhibiting drugs.

Coptidis Rhizoma Extract Reverses 5-Fluorouracil Resistance in HCT116 Human Colorectal Cancer Cells via Modulation of Thymidylate Synthase

Colorectal cancer (CRC) is a malignancy of the colon or rectum. It is ranked as the third most common cancer in both men and women worldwide. Early resection permitted by early detection is the best treatment, and chemotherapy is another main treatment, particularly for patients with advanced CRC. A well-known thymidylate synthase (TS) inhibitor, 5-fluorouracil (5-FU), is frequently prescribed to CRC patients; however, drug resistance is a critical limitation of its clinical application. Based on the hypothesis that Coptidis Rhizoma extract (CRE) can abolish this 5-FU resistance, we explored the efficacy and underlying mechanisms of CRE in 5-FU-resistant (HCT116/R) and parental HCT116 (HCT116/WT) cells. Compared to treatment with 5-FU alone, combination treatment with CRE and 5-FU drastically reduced the viability of HCT116/R cells. The cell cycle distribution assay showed significant induction of the G0/G1 phase arrest by co-treatment with CRE and 5-FU. In addition, the combination of CRE and 5-FU notably suppressed the activity of TS, which was overexpressed in HCT116/R cells, as compared to HCT116/WT cells. Our findings support the potential of CRE as an adjuvant agent against 5-FU-resistant colorectal cancers and indicate that the underlying mechanisms might involve inhibition of TS expression.

Cross-talk of Signaling Pathways in the Pathogenesis of Allergic Asthma and Cataract

Allergic asthma is a chronic inflammatory disease, which involves many cellular and cellular components. Cataract is a condition that affects the transparency of the lens, which the opacity of the lens caused by any innate or acquired factor degrades its transparency or changes in color. Both of them belong to diseases induced by immune disorders or inflammation. We want to confirm the signaling pathways involved in the regulation of asthma and cataract simultaneously, and provide reference for the later related experiments. So we conducted a scoping review of many databases and searched for studies (Academic research published in Wiley, Springer and Bentham from 2000 to 2019) about the possible relationship between asthma and cataract. It was found that during the onset of asthma and cataract, Rho/Rock signaling pathway, Notch signaling pathway, Wnt/β-catenin signaling pathway, PI3K/AKT signaling pathway, JAK/STAT signaling pathway, MAPK signaling pathway, TGF-β1/Smad signaling pathway and NF-κB signaling pathway are all active, so they may have a certain correlation in pathogenesis. Asthma may be associated with cataract through the eight signaling pathways, causing inflammation or immune imbalance based on allergy that can lead to cataract. According to these studies, we speculated that the three most likely signaling pathways are PI3K/AKT, MAPK and NF-κB signaling pathway.

Whole genome sequencing of metastatic colorectal cancer reveals prior treatment effects and specific metastasis features

In contrast to primary colorectal cancer (CRC) little is known about the genomic landscape of metastasized CRC. Here we present whole genome sequencing data of metastases of 429 CRC patients participating in the pan-cancer CPCT-02 study (NCT01855477). Unsupervised clustering using mutational signature patterns highlights three major patient groups characterized by signatures known from primary CRC, signatures associated with received prior treatments, and metastasis-specific signatures. Compared to primary CRC, we identify additional putative (non-coding) driver genes and increased frequencies in driver gene mutations. In addition, we identify specific genes preferentially affected by microsatellite instability. CRC-specific 1kb-10Mb deletions, enriched for common fragile sites, and LINC00672 mutations are associated with response to treatment in general, whereas FBXW7 mutations predict poor response specifically to EGFR-targeted treatment. In conclusion, the genomic landscape of mCRC shows defined changes compared to primary CRC, is affected by prior treatments and contains features with potential clinical relevance.

5-Fluorouracil (5-FU) resistance and the new strategy to enhance the sensitivity against cancer: Implication of DNA repair inhibition

5-Fluorouracil (5-FU) has been an important anti-cancer drug to date. With an increase in the knowledge of its mechanism of action, various treatment modalities have been developed over the past few decades to increase its anti-cancer activity. But drug resistance has greatly affected the clinical use of 5-FU. Overcoming this chemoresistance is a challenge due to the presence of cancer stem cells like cells, cancer recurrence, metastasis, and angiogenesis. In this review, we have systematically discussed the mechanism of 5-FU resistance and advent strategies to increase the sensitivity of 5-FU therapy including resistance reversal. Special emphasis has been given to the cancer stem cells (CSCs) mediated 5-FU chemoresistance and its reversal process by different approaches including the DNA repair inhibition process.

Natural Compounds That Target DNA Repair Pathways and Their Therapeutic Potential to Counteract Cancer Cells

Resistance to current cancer treatments is an important problem that arises through various mechanisms, but one that stands out involves an overexpression of several factors associated with DNA repair. To counteract this type of resistance, different drugs have been developed to affect one or more DNA repair pathways, therefore, to test different compounds of natural origin that have been shown to induce cell death in cancer cells is paramount. Since natural compounds target components of the DNA repair pathways, they have been shown to promote cancer cells to be resensitized to current treatments. For this and other reasons, natural compounds have aroused great curiosity and several research projects are being developed around the world to establish combined treatments between them and radio or chemotherapy. In this work, we summarize the effects of different natural compounds on the DNA repair mechanisms of cancer cells and emphasize their possible application to re-sensitize these cells.

Nanoformulated quinacrine regulates NECTIN-4 domain specific functions in cervical cancer stem cells

NECTIN-4 [a poliovirus receptor-related-4 (PVRL-4) encoded gene] has vital roles in cancer proliferation, metastasis and angiogenesis. It possesses three different domains and it is predicted that they have different roles in cancer but the structure-function relationship is still unknown and hence carrying out a detailed study to elucidate the domain-specific functions of NECTIN-4 in cancer is necessary. Using 5-Fluouracil-resistant cervical cancer stem cells (PEMT-5FU-R-MC) and different NECTIN-4 domain-specific constructs, different domains of NECTIN-4 were over-expressed in PEMT-5FU-R-MC cells. Biochemical assays like comet, γ-H2AX immunofluorescence, western blot, in vitro tube formation, gelatin zymography, in ovo CAM assay, etc. were used to delineate the function of each domain of NECTIN-4 in cancer and their regulation by nano-formulated quinacrine (NQC). Endo-domain (lacking extracellular region corresponding to aa 30-347) and ecto-domain (lacking signal peptide and cytoplasmic region corresponding to aa 1-29 and 348-509, respectively) of NECTIN-4 were largely overexpressed in nucleus and cytoplasm, respectively. Endo-domain translocates into nucleus by physically interacting with IMPORTIN-α2, activates the DNA repair and enhances cell growth, whereas ecto-domain specifically activates angiogenesis by modulating representative angiogenic markers, inducing in vitro tube formation and in ovo blood vessel formation. Full-length NECTIN-4 (aa 1-509) was overexpressed in both nucleus and cytoplasm and modulated both DNA repair and angiogenesis. NQC down-regulated these phenomena by modulating the endo-domain and ecto-domain of NECTIN-4. Thus, current study suggested that endo-domain of NECTIN-4 translocated into nucleus and increased the DNA repair and ecto-domain of NECTIN-4 enhanced the angiogenesis, whereas NQC inhibits these processes.

Mechanisms of resveratrol in the prevention and treatment of gastrointestinal cancer

Gastrointestinal (GI) cancer is one of the leading causes of cancer-related deaths worldwide. According to the Global Cancer Statistics, colorectal cancer is the second leading cause of cancer-related mortality, closely followed by gastric cancer (GC). Environmental, dietary, and lifestyle factors including cigarette smoking, alcohol intake, and genetics are the most important risk factors for GI cancer. Furthermore, infections caused by Helicobacter pylori are a major cause of GC initiation. Despite improvements in conventional therapies, including surgery, chemotherapy, and radiotherapy, the length or quality of life of patients with advanced GI cancer is still poor because of delayed diagnosis, recurrence and side effect. Resveratrol (3, 4, 5-trihydroxy-trans-stilbene; Res), a natural polyphenolic compound, reportedly has various pharmacologic functions including anti-oxidant, anti-inflammatory, anti-cancer, and cardioprotective functions. Many studies have demonstrated that Res also exerts a chemopreventive effect on GI cancer. Research investigating the anti-cancer mechanism of Res for the prevention and treatment of GI cancer has implicated multiple pathways including oxidative stress, cell proliferation, and apoptosis. Therefore, this paper provides a review of the function and molecular mechanisms of Res in the prevention and treatment of GI cancer.

Cysteinyl leukotriene receptor 1 promotes 5-fluorouracil resistance and resistance-derived stemness in colon cancer cells

Colon cancer is a therapy-resistant cancer with a low 5-year survival frequency. The drug 5-fluorouracil (5-FU) has been used as a first-line therapy in metastatic colon cancer in combination with leucovorin or oxaliplatin with a >40% resistance rate. High CysLT₁R expression in tumors is associated with poor survival of colon cancer patients. We sought to examine the role of CysLT₁R in 5-FU resistance and established 5-FU-resistant (5-FU-R) colon cancer cells. These 5-FU-R-cells expressed increased levels of CysLT₁R and showed increased survival and migration compared to nonresistant cells. Increases in thymidylate synthase and active β-catenin were also observed in the 5-FU-R-cells. LTD₄/CysLT₁R signaling was further increased and abolished after CYSLTR1 CRISPR-Cas9-knockdown and reduced in CysLT₁R-doxycycline-knockdown experiments and CysLT₁R-antagonist montelukast/5-FU-treated cells. Montelukast and 5-FU resulted in synergistic effects by reducing HT-29 cell and 5-FU-R-HT-29 cell migration and zebrafish xenograft metastasis. An increase in the stem cell markers in 5-FU-R-cells and 5-FU-R-cell-derived colonospheres and in CysLT₁R-Dox-knockdown cells increased colonosphere formation and stem cell markers was noticed after 5-FU treatment. IL-4-mediated stemness in both HT-29-colonospheres and 5-FU-R-cell derived colonospheres was abolished by montelukast or montelukast + 5-FU-treatment. Targeting CysLT₁R signaling by montelukast might reverse drug resistance and decrease resistance-derived stemness in colon cancer patients.

RV-59 suppresses cytoplasmic Nrf2-mediated 5-fluorouracil resistance and tumor growth in colorectal cancer

Our previous studies indicated that tumor invasion and 5-flurouracil (5-FU) resistance in colorectal cancer (CRC) was more affected by cytoplasmic localization of expressed Nrf2 (cNrf2) than by nuclear localization (nNrf2), indicating a need for novel antitumor agents to overcome 5-FU resistance and improve outcomes in patients with CRC. In the present study, 20 nitrogen-substituted anthra[1,2-c][1,2,5] thiadiazole-6,11-dione derivatives were collected to verify the compound most able to suppress cell growth in nuclear location sequence (NLS)-mutated Nrf2-transfected shNrf2-HCT116 stable clones that have high cNrf2 expression. The MTT assay indicated that these high-cNrf2-expressing shNrf2-HCT116 stable clones exhibited the lowest percentage survival when treated with RV-59 than with the other 19 compounds. As expected, the high-cNrf2-expressing cells also showed a higher value for the inhibitory concentration of 50% cell survival (IC50) for 5-FU when compared with Nrf2-knockdown HCT116 stable clones (17.74 μM vs. 5.34 μM). Interestingly, a lower RV-59 IC50 value was seen in the high-cNrf2-expressing stable clones than in the Nrf2-knockdown stable clones (3.55 μM vs. 16.81 μM). A similar low RV-59 IC50 value was observed in high-cNrf2-expressing NLS-mutated Nrf2-transfected shNrf2-HCT116 stable clones and p53 null (-/-) HCT116 cells (4.2 μM vs. 4.4 μM), whereas the IC50 value was 17.6 μM in normal colon FHC epithelial cells. Colony-forming assays confirmed that RV-59 treatment inhibited colony formation in NLS-mutated Nrf2-transfected shNrf2-HCT116 stable clones and in p53^-/- HCT116 cells. Annexin-V/PI staining showed an involvement of apoptosis in the inhibitory effect of RV-59 on cell viability. A nude mouse xenograft tumor model showed that RV-59 efficiently suppressed tumor growth induced by transplanted NLS-mutated Nrf2-transfected shNrf2-HCT116 stable clones without affecting the body weight of the nude mice over the 37 day experimental period. These results strongly suggest that RV-59 may be a novel antitumor agent for suppression of 5-FU resistance and may have therapeutic potential for improving outcomes in patients with cNrf2-expressing tumors.

Synthesis of Novel Analogs of Thieno[2,3-d] Pyrimidin-4(3H)-ones as Selective Inhibitors of Cancer Cell Growth

New 2,3-disubstituted thieno[2,3-d]pyrimidin-4(3H)-ones were synthesized via a one-pot reaction from 2H-thieno[2,3-d] [1,3]oxazine-2,4(1H)-diones, aromatic aldehydes, and benzylamine or 4-hydroxylbezylamine. The obtained compounds were tested in vitro for cancer cell growth inhibition. Compound 19 can inhibit all four types of tested cancer cells, i.e., MCF-7, A549, PC-9, and PC-3 cells. Most of the compounds inhibited the proliferation of A549 and MCF-7 cells. Compound 15 exhibited the strongest anti-proliferative effect against A549 cell lines with IC50 values of 0.94 μM, and with no toxicity to normal human liver cells. Its potency was further proved by cell clone formation assay, Hoechst 33258 staining, and evaluation on the effects of apoptosis-related proteins.

Melatonin-mediated downregulation of thymidylate synthase as a novel mechanism for overcoming 5-fluorouracil associated chemoresistance in colorectal cancer cells

BACKGROUND

5-Fluorouracil (5-FU) has been established as the first-line chemotherapy for advanced colorectal cancer (CRC); however, acquired chemoresistance is often the cause of poor therapeutic response. Melatonin is a molecule that is associated with circadian rhythms. Although antitumor effects of melatonin have been shown, the underlying mechanism(s) for its activity and its effect, if any, in chemoresistant CRC has not been studied. We aimed to investigate antitumor effects of melatonin, and more specifically its effect on molecular mechanisms in 5-FU resistant CRC cells.

METHODS

The cell growth was assessed in CRC cells, patient-derived organoids and 5-FU resistant CRC cells after treatments with melatonin. In addition, the expression of thymidylate synthase (TYMS) and microRNAs (miRNAs) that are targeting TYMS were examined.

RESULTS

We observed that melatonin inhibited the cell growth in 5-FU resistant CRC cells. In addition, we found that melatonin significantly promoted apoptosis. Furthermore, a combination of melatonin and 5-FU markedly enhanced 5-FU-mediated cytotoxicity in 5-FU resistant cells. In addition, melatonin significantly decreased the expression of TYMS. Interestingly, this effect was manifested through the simultaneous increase in the expression of miR-215-5p, for which, TYMS serves as the direct downstream target for this miRNA.

CONCLUSIONS

Melatonin facilitates overcoming 5-FU resistance through downregulation of TYMS. Melatonin may serve as a potential therapeutic option on its own, or in conjunction with 5-FU, in the treatment of patients with advanced or chemoresistant CRC.Melatonin inhibits the growth of 5-FU resistant colorectal cancer (CRC) cells through upregulation of miR-215-5p and a concomitant downregulation of TYMS. Melatonin may serve as a potential therapeutic option in the treatment of patients with advanced or chemoresistant CRC.

Nanoquinacrine sensitizes 5-FU-resistant cervical cancer stem-like cells by down-regulating Nectin-4 via ADAM-17 mediated NOTCH deregulation

PURPOSE

Cervical cancer is a major cause of cancer-related death in women world-wide. Although the anti-metabolite 5-FU is widely used for its treatment, its clinical utility is limited due to the frequent occurrence of drug resistance during metastasis. Cancer stem-like cells (CSCs), present in the heterogeneous population of CC cells, are thought to contribute to this resistance. Nectin-4, a CSC marker, is known to play an important role in the cellular aggressiveness associated with metastatic CC. This study was designed to assess the role of Nectin-4 in the acquisition of 5-FU resistance by metastatic CC cells, including its relation to the NOTCH signalling pathway.

METHODS

5FU-resistant CC cell lines were deduced from ME-180 and SiHA cells by continuous exposure to a single concentration of 5-FU. Thymidylate synthase (TS) positive cells were isolated from the 5-FU resistant cells, after which a metastatic model was developed. The role of Nectin-4 in the sensitization of 5-FU resistant metastatic CC cells upon incubation with Nano-formulated Quinacrine (NQC) was investigated using multiple bioassays including MTT, FACS, ELISA, immunoflurescence, Western blotting, comet and in vivo plasmid-based short patch and long patch base excision repair assays.

RESULTS

We found that the expression level of Nectin-4, as well as that of other CSC markers (Oct-4, β-catenin, SOX2) and representative NOTCH signalling components (NOTCH-1, Jagged-1, γ-secretase, ADAM-17) were elevated in the 5-FU resistant metastatic cells compared to those in control cells. Increased nuclear translocation of Nectin-4 and increased proliferation and invasion rates were observed after culturing the metastatic cells under hypoxic conditions. Treatment with NQC inhibited the nuclear translocation of Nectin-4 and decreased the proliferation and invasion rates of the cells by inhibiting the induction of base excision repair (BER) pathway components and ADAM-17 expression levels. After combination treatment of Nectin-4 overexpressing metastatic CC cells with a specific ADAM-17 inhibitor (GW280264) and NQC, a decreased Nectin-4 expression, without alterations in BER and/or other NOTCH pathway components, was noted.

CONCLUSION

Our data indicate that Nectin-4 may play a prominent role in 5-FU resistance of metastatic CC cells and that NQC sensitizes these cells by Nectin-4 deregulation through ADAM-17 inhibition, a major component of the NOTCH signalling pathway.

NBGNU: a hypoxia-activated tripartite combi-nitrosourea prodrug overcoming AGT-mediated chemoresistance

Aim: A hypoxia-activated combi-nitrosourea prodrug, N-(2-chloroethyl)-N'-2-(2-(4-nitrobenzylcarbamate)-O ⁶-benzyl-9-guanine)ethyl-N-nitrosourea (NBGNU), was synthesized and evaluated for its hypoxic selectivity and anticancer activity in vitro. Results: The prodrug was designed as a tripartite molecule consisting of a chloroethylnitrosourea pharmacophore to induce DNA interstrand crosslinks (ICLs) and an O ⁶-benzylguanine analog moiety masked by a 4-nitrobenzylcarbamate group to induce hypoxia-activated inhibition of O ⁶-alkylguanine-DNA alkyltransferase. NBGNU was tested for hypoxic selectivity, cytotoxicity and DNA ICLs ability. The reduction product amounts, cell death rates and DNA ICL levels induced by NBGNU under hypoxic conditions were all significantly higher than those induced by NBGNU under normoxic conditions. Conclusion: The tripartite combi-nitrosourea prodrug exhibits desirable tumor-hypoxia targeting ability and abolished chemoresistance compared with the conventional chloroethylnitrosoureas.

The long non-coding RNA Neat1 is an important mediator of the therapeutic effect of bexarotene on traumatic brain injury in mice

OBJECTIVE

Bexarotene treatments exert neuroprotective effects on mice following traumatic brain injury (TBI). The present study aims to investigate the potential roles of the long noncoding RNA Neat1 in the neuroprotective effects of bexarotene.

MATERIALS AND METHODS

Adult male C57BL/6J mice (n=80) and newborn mice (within 24h after birth) (n=20) were used to generate a "controlled cortical impact" (CCI) model and harvest primary cortex neurons, respectively. The HT22 cell line and the BV2 cell line were cultured under "normal" or "oxygen/glucose-deprived" (OGD) conditions. The relationship between RXR-α and the Neat1 promoter was clarified using ChIP-qPCR and dual-luciferase reporter gene assays. The mRNA alterations induced by Neat1 knockdown were measured using next-generation RNA sequencing. Proteins were captured by Neat1, pulled down and subjected to mass spectrometry. The neurological severity score, rotarod test and water maze test were employed to measure the animals' motor and cognitive functions.

RESULTS

Bexarotene prominently up-regulated the Neat1 level in an RXR-α-dependent manner. Neat1 knockdown induced significant changes in mRNA expression, and the altered mRNAs were involved in many biological processes, including synapse formation and axon guidance. In primary neurons, Neat1 knockdown inhibited and Neat1 over-expression prompted axon elongation. Multiple proteins, including Pidd1, were captured by Neat1. Neat1 inhibited cell apoptosis and restricted inflammation by capturing Pidd1. The in vitro anti-apoptotic and anti-inflammatory effects of Neat1 were further confirmed in C57BL/6 mice, which resulted in better motor and cognitive function after TBI.

CONCLUSION

Bexarotene up-regulates the lncRNA Neat1, which inhibits apoptosis and inflammation, thereby resulting in better functional recovery in mice after TBI.

Annexin A2 could enhance multidrug resistance by regulating NF-κB signaling pathway in pediatric neuroblastoma

Background

Chemotherapy is one of major therapeutic regimens for neuroblastoma (NB) in children. However, recurrence and metastasis associated with poor prognosis caused by acquired multidrug resistance remains a challenge. There is a great need to achieve new insight into the molecular mechanism of drug resistance in NB. The aim of this study is to identify novel drug sensitivity-related biomarkers as well as new therapeutic targets to overcome chemoresistance.

Methods

We proteome-wide quantitatively compared protein expression of two NB cell lines with different drug sensitivities, isolated from the same patient prior to and following chemotherapy. Annexin A2 (ANXA2) emerged as a key factor contributing to drug resistance in NB. Then, we assessed the correlation of ANXA2 expression and clinical characteristics using a tissue microarray. Further, the roles of ANXA2 in chemoresistance for NB and the underlying mechanisms were studied by using short hairpin RNA (shRNA) in vitro and vivo.

Results

First in total, over 6000 proteins were identified, and there were about 460 significantly regulated proteins which were up- or down-regulated by greater than two folds. We screened out ANXA2 which was upregulated by more than 12-fold in the chemoresistant NB cell line, and it might be involved in the drug resistance of NB. Then, using a tissue chip containing 42 clinical NB samples, we found that strong expression of ANXA2 was closely associated with advanced stage, greater number of chemotherapy cycles, tumor metastasis and poor prognosis. Following knockdown of ANXA2 in NB cell line SK-N-BE(2) using shRNA, we demonstrate enhanced drug sensitivity for doxorubicin (2.77-fold) and etoposide (7.87-fold) compared with control. Pro-apoptotic genes such as AIF and cleaved-PARP were upregulated. Inhibiting ANXA2 expression attenuated transcriptional activity of NF-κB via down-regulated nuclear translocation of subunit p50. Finally, simulated chemotherapy in a xenograft NB nude mouse model suggests that ANXA2 knockdown could improve clinical results in vivo.

Conclusion

Our profiling data provided a rich source for further study of the molecular mechanisms of acquired drug resistance in NB. Further study may determine the role of ANXA2 as a prognostic biomarker and a potential therapeutic target for patients with multidrug-resistant NB.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0581-6) contains supplementary material, which is available to authorized users.

K9(C4H4FN2O2)2Nd(PW11O39)2·25H2O induces apoptosis in human lung cancer A549 cells

Lung cancer is the leading cause of cancer-associated mortality worldwide. The present study investigated the effects of K₉(C₄H₄FN₂O₂)₂Nd(PW₁₁O₃₉)₂·25H₂O (FNdPW), a chemically synthesized polyoxometalate that contains rare earth elements, on lung cancer growth, and explored the mechanism underlying its actions. The effects of FNdPW on the cell viability and apoptosis of human lung cancer A549 cells were measured using MTT assay, acridine orange/ethidium bromide staining and electron microscopy. The expression of apoptosis-related proteins, including B-cell lymphoma (Bcl)-2-associated death promoter (Bad), phosphorylated (p)-Bad, X-linked inhibitor of apoptosis (XIAP), apoptosis-inducing factor (AIF), Bcl-2-associated X protein (Bax) and Bcl-2, was determined by western blotting. Caspase-3 activity was measured using a caspase-3 activity kit. After 72 h of incubation, FNdPW reduced cell viability and induced apoptosis in A549 cells in a concentration- and time-dependent manner. FNdPW upregulated the pro-apoptotic Bad and Bax proteins, and downregulated the anti-apoptotic p-Bad, Bcl-2 and XIAP proteins. Furthermore, FNdPW also enhanced caspase-3 activity and increased the protein level of AIF in A549 cells, which was independent of the caspase-3 pathway. These events were associated with the regulation exerted by FNdPW on multiple targets involved in A549 cell proliferation. Therefore, FNdPW may be a novel drug for the treatment of lung cancer.

Research progress on chemopreventive effects of phytochemicals on colorectal cancer and their mechanisms

Colorectal cancer (CRC) is a type of cancer with high morbidity and mortality rates worldwide and has become a global health problem. The conventional radiotherapy and chemotherapy regimen for CRC not only has a low cure rate but also causes side effects. Many studies have shown that adequate intake of fruits and vegetables in the diet may have a protective effect on CRC occurrence, possibly due to the special biological protective effect of the phytochemicals in these foods. Numerous in vitro and in vivo studies have demonstrated that phytochemicals play strong antioxidant, anti-inflammatory and anti-cancer roles by regulating specific signaling pathways and molecular markers to inhibit the occurrence and development of CRC. This review summarizes the progress on CRC prevention using the phytochemicals sulforaphane, curcumin and resveratrol, and elaborates on the specific underlying mechanisms. Thus, we believe that phytochemicals might provide a novel therapeutic approach for CRC prevention, but future clinical studies are needed to confirm the specific preventive effect of phytochemicals on cancer.

5-Fluorouracil and interleukin-2 immunochemotherapy enhances immunogenicity of non-small cell lung cancer A549 cells through upregulation of NKG2D ligands

BACKGROUND

The aim of this study was to investigate the anti-cancer effects and mechanisms of immunochemotherapy of 5-fluorouracil (5-FU) and interleukin-2 (IL-2) on non-small cell lung cancer (NSCLC) A549 cells.

MATERIALS AND METHODS

In order to detect whether 5-FU+IL-2 could effectively inhibit tumor growth in vivo, we established an A549-bearing nude mouse model. The cytotoxicity of natural killer (NK) cells was evaluated using a standard chromium release assay. To evaluate the relevance of NK cells in 5-FU+IL-2- mediated tumor inhibitory effects, we depleted NK cells in A549-bearing mice by injecting anti-asialo-GM-1 antibodies. Effects of 5-FU+IL-2 on the expression and promoter activity of NKG2D ligands (MICA/MICB) in A549 cells in vitro were also assessed.

RESULTS

In A549-bearing nude mice, combination therapy significantly inhibited tumor growth in comparison with monotherapy with 5-FU or IL-2 and enhanced the recognition and lysis of tumor cells by NK cells. Further study of mechanisms showed that NK cells played a vital role in the anticancer immune response of 5-FU+IL-2 immunochemotherapy. In addition, the combination therapy synergistically stimulated the expression and promoter activity of MICA/MICB.

CONCLUSIONS

5-FU and IL-2 immunochemotherapy significantly inhibited tumor growth and activated NK cytotoxicity in vivo, and these effects were partly impaired after depleting NK cells in tumor-bearing mice. Combination treatment of 5-FU and IL-2 upregulated the expression and the promoter activity of MICA/MICB in A549 cells, which enhanced the recognition of A549 cells by NK cells. All of the data indicated that immunochemotherapy of 5-FU and IL-2 may provide a new treatment option for patients with lung cancer.

Flap endonuclease 1 silencing is associated with increasing the cisplatin sensitivity of SGC‑7901 gastric cancer cells

Flap endonuclease 1 (FEN1), which is key in DNA replication and repair, has been demonstrated to be intimately involved in the development and progression of cancer. Our previous study determined that the downregulation of FEN1 can suppress the proliferation of, and induce apoptosis in, gastric cancer SGC‑7901 cells. In addition, several FEN1 inhibitors have been identified to increase sensitisation to DNA injury agents. These results may provide a promising treatment method to enhance the traditional chemotherapeutics used for the treatment of gastric cancer. Thus, the aim of the present study was to determine the role of FEN1 in the chemosensitivity of SGC‑7901 cells. The protein expression levels of FEN1 in cisplatin (CDDP)‑treated SGC‑7901 cells were detected using western blot analysis. FEN1 was silenced via specific FEN1‑targeted small interfering RNAs (siRNA). The survival and apoptotic rates of the SGC‑7901 cells were assessed using an MTT assay and flow cytometry, respectively. Relevant apoptotic factors were detected using western blotting. The results showed that the expression of FEN1 was significantly induced by CDDP in a dose‑ and time‑dependent manner. The targeting of FEN1 in SGC‑7901 cells, in combination with CDDP treatment, significantly inhibited their proliferation and effectively increased their apoptotic rate. In addition, in the cells targeted with FEN1‑siRNA and exposed to CDDP, the levels of Bcl‑2‑associated X protein were significantly increased, whereas the expression levels of Bcl‑2 and Bcl‑extra large were effectively decreased, compared with the cells exposed to negative control‑siRNA and CDDP. These results suggest a potential chemotherapeutic target, which exhibits enhanced sensitivity to CDDP following FEN1 silencing in SGC‑7901 cells via decreased survival and increased apoptosis.

Resveratrol and curcumin synergistically induces apoptosis in cigarette smoke condensate transformed breast epithelial cells through a p21(Waf1/Cip1) mediated inhibition of Hh-Gli signaling

Combination therapy using two or more small molecule inhibitors of aberrant signaling cascade in aggressive breast cancers is a promising therapeutic strategy over traditional monotherapeutic approaches. Here, we have studied the synergistic mechanism of resveratrol and curcumin induced apoptosis using in vitro (cigarette smoke condensate mediated transformed breast epithelial cell, MCF-10A-Tr) and in vivo (tumor xenograft mice) model system. Resveratrol exposure increased the intracellular uptake of curcumin in a dose dependent manner and caused apoptosis in MCF-10A-Tr cells. Approximately, ten fold lower IC50 value was noted in cells treated with the combination of resveratrol (3μM) and curcumin (3μM) in comparison to 30μM of resveratrol or curcumin alone. Resveratrol+curcumin combination caused apoptosis by increasing Bax/Bcl-xL ratio, Cytochrome C release, cleaved product of PARP and caspase 3 in cells. Interestingly, this combination unaltered the protein expressions of WNT-TCF and Notch signaling components, β-catenin and cleaved notch-1 val1744, respectively. Furthermore, the combination also significantly decreased the intermediates of Hedgehog-Gli cascade including SMO, SHH, Gli-1, c-MYC, Cyclin-D1, etc. and increased the level of p21(Waf/Cip1) in vitro and in vivo. A significant reduction of Gli- promoter activity was noted in combinational drug treated cells in comparison to individual drug treatment. Un-alteration of the expressions of the above proteins and Gli1 promoter activity in p21(Waf/Cip1) knockout cells suggests this combination caused apoptosis through p21(Waf/Cip1). Thus, our findings revealed resveratrol and curcumin synergistically caused apoptosis in cigarette smoke induced breast cancer cells through p2(Waf/Cip1) mediated inhibition of Hedgehog-Gli cascade.

NECTIN-4 increased the 5-FU resistance in colon cancer cells by inducing the PI3K-AKT cascade

PURPOSE

5-Fluorouracil is the most commonly used drug for the treatment of colon cancer, yet clinical resistance to this drug is frequently observed in patients making this drug ineffective. Thus, identification of gene responsible for 5-FU resistance is of utmost importance.

METHODS

Cellular cytotoxicity and expressions of different protein markers in colon cancer cells were measured by MTT assay and Western blotting, respectively. Cell cycle regulation, migration and colony formation ability were measured by FACS, wound-healing assay and clonogenic assay, respectively.

RESULTS

Increased NECTIN-4 expression was observed in 5-FU-resistant (5-FU-R) and 5-FU-exposed HCT-116 cells. A significant increase in the cell proliferation, migration, colony formation, and resistant to 5-FU were noted in 5-FU-R cells, but reverse was observed after silencing of NECTIN-4. Apoptosis caused by 5-FU in 5-FU-R cells after NECTIN-4 knockdown indicates that NECTIN-4 is responsible for 5-FU resistance. Cell survival proteins were upregulated in 5-FU-R and NECTIN-4-over-expressed cells and downregulated in NECTIN-4 knockdown or LY294002-pretreated 5-FU-R cells. Drug combination of BCNU + Resveratrol decreased the cell survival and NECTIN-4 expressions in 5-FU-R cells and NECTIN-4-over-expressed cells.

CONCLUSIONS

Our data suggest that NECTIN-4 is responsible for 5-FU resistance and BCNU + Resveratrol combination can be used to increase the 5-FU sensitivity.

IN-VITRO evidence for the protective properties of the main components of the Mediterranean diet against colorectal cancer: A systematic review

AIM

Epidemiological studies have shown that the incidence and mortality rates of colorectal cancer (CRC) vary over 10-fold worldwide where within Westernized societies lower rates are observed amongst populations living within the Mediterranean basin, suggesting a significant influence of environment and dietary style in CRC carcinogenesis. Interpretation of the data concerning the benefits of mediterranean (MD) diet is difficult in vivo because of the variability of alimentary regimens used, the differing compliance with dietary supplementation and because of the non-uniform duration of patient cohort observation. Therefore, the aim of this review is to evaluate the in-vitro effects on colorectal cancer cell lines.

METHODS

the literature concerning the in-vitro effects of 4 of the principal components symbolizing the MD such as olive oil (polyphenol), red chili (capsaicin), tomato (lycopene) and red grapes (resveratrol) have been systematically reviewed.

RESULTS

Several studies have demonstrated that polyphenols form olive oil, lycopene, resveratrol and capsaicin have multiple anticancer properties affecting several metabolic pathways involved in cancerogenesis, apoptosis, and metastasis in CRC cell lines.

CONCLUSION

This review summarizes some of the most recent data potentially supportive of the use of MD in CRC chemoprevention, analyzing the in vitro effects of individual components of the MD on CRC cell development, progression, metastasis and apoptosis.

Glucose-induced glutathione reduction in mitochondria is involved in the first phase of pancreatic β-cell insulin secretion

Glucose can acutely reduce mitochondrial glutathione redox state in rat islets. However, whether glucose-stimulated mitochondrial glutathione redox state relates to glucose-stimulated insulin secretion (GSIS) remains unknown. We used genetically encoded redox-sensitive GFPs to target the mitochondria to monitor glutathione redox changes during GSIS in rat pancreatic β-cells. The results showed that mitochondrial glutathione was more reduced during GSIS, whereas inhibition of this glutathione reduction impaired insulin secretion. In isolated rat pancreatic islets glutathione reduction in mitochondria and the first phase of GSIS were concurrence at the early stage of glucose-stimulation. Our results suggest that the glucose-induced glutathione reduction in mitochondria is primarily required for the first phase of GSIS.