Heightened JNK Activation and Reduced XIAP Levels Promote TRAIL and Sunitinib-Mediated Apoptosis in Colon Cancer Models

Soluble B7 and TNF family in colorectal cancer: Serum level, prognostic and treatment value

Soluble immune checkpoints (sIC) are crucial factors in the immune system. They regulate immune responses by transforming intercellular signals via binding to their membrane-bound receptor or ligand. Moreover, soluble ICs are vital in immune regulation, cancer development, and prognosis. They can be identified and measured in various tumor microenvironments. Recently, sICs have become increasingly important in clinically assessing malignancies like colorectal cancer (CRC) patients. This review explores the evolving role of the soluble B7 family and soluble tumor necrosis factor (TNF) superfamily members in predicting disease progression, treatment response, and overall patient outcomes in CRC. We comprehensively analyze the diagnostic and prognostic potential of soluble immune checkpoints in CRC. Understanding the role of these soluble immune checkpoints in CRC management and their potential as targets for precision medicine approaches can be critical for improving outcomes for patients with colorectal cancer.

Metformin induces apoptosis in TRAIL-resistant colorectal cancer cells

Resistance to chemotherapy drugs, which commonly occurs during the treatment of colorectal cancer (CRC), can lead to tumor recurrence and metastasis, so combinational treatment strategies according to the cancer cell type are urgently needed to overcome drug resistance and increase therapeutic efficiency. To this end, the tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a promising anticancer strategy. Some CRC cell lines such as SW620 have low sensitivity to TRAIL, so additional sensitizers are required to make the strategy effective. Therefore, we focused on the apoptotic effect of combinational metformin and TRAIL treatment on TRAIL-resistant SW620 cells. Treatment with TRAIL alone did not induce apoptosis whereas combined treatment with metformin and TRAIL significantly increased it. TRAIL activated caspases through an extrinsic pathway but increased resistance to apoptosis through the protein kinase B or AKT (PKB/AKT)/mammalian target of rapamycin (mTOR) pathway. On the other hand, metformin reduced the inhibitory effect of X-linked inhibitor of apoptosis (XIAP) by blocking the AKT and nuclear factor kappa B (NF-κB) pathways and activated CCAAT-enhancer-binding protein homologous protein (CHOP) via endoplasmic reticulum (ER) stress but without inducing apoptosis. In addition, metformin induced cell-cycle arrest, thereby blocking cell proliferation and growth. These results were also confirmed through an in vivo mouse xenograft CRC model, in which combined treatment with metformin and TRAIL induced tumor cell death, thus demonstrating the anticancer effect of their coadministration. Therefore, cotreatment of metformin and TRAIL could be an effective anticancer treatment strategy for TRAIL-resistant CRC.

Construction and validation of a novel tumor necrosis factor-related apoptosis-inducing ligand mutant MuR5S4-TR

AIM

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can selectively kill tumor cells but has no significant effect on normal cells. However, the use of TRAIL is limited for resistance by more than 50% of the tumor cell lines. It's very important to develop a more efficient form of TRAIL for cancer treatment.

METHODS

The N-terminal in soluble fragments (114-281aa) of TRAIL was redesigned to construct a novel TRAIL mutant-MuR5S4-TR. The Cell Counting Kit-8 method to explore the antitumor effects. The potential mechanisms were also explored.

RESULTS

Novel TRAIL mutant with cell-penetrating peptides (CPP) like and Second mitochondria-derived activator of caspases (Smac) like structure-MuR5S4-TR was successfully constructed. The prokaryotic expression system was successfully built, and the MuR5S4-TR was purified and reconfirmed by western blot. MuR5S4-TR could enhance the antitumor effects of TRAIL in most of the cancer cell lines significantly, NCI-H460 lung cancer cell line, for instance. After MuR5S4-TR treatment, the expressions of death receptor 4 (DR4), DR5, Caspase-8, and cleaved Caspase-3 were remarkably increased, however, there was no significant difference in X-linked inhibitor of apoptosis expression.

CONCLUSION

We constructed a novel TRAIL mutant with CPP-like and Smac-like structure-MuR5S4-TR. The MuR5S4-TR showed significantly stronger antitumor effects than TRAIL in many tumor cell lines. The MuR5S4-TR showed strong antitumor effects both in vitro and in vivo. This preliminary study implies that MuR5S4-TR may be a more efficient form of TRAIL for cancer therapy.

Role of phloretin as a sensitizer to TRAIL‑induced apoptosis in colon cancer

Phloretin is one of the apple polyphenols with anticancer activities. Since tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) serves important roles in inducing apoptosis, the present study examined the effect of phloretin on TRAIL-induced apoptosis in colon cancer cells. Treatment with both phloretin and TRAIL markedly suppressed the survival of cancer cells from several colon cancer cell lines compared with that of cells treated with either TRAIL or phloretin. Additionally, decreased numbers of colonies were observed following addition of phloretin and TRAIL. Furthermore, TRAIL- and phloretin-treated HT-29-Luc cells exhibited decreased luciferase activity. Increased apoptosis was observed in phloretin- and TRAIL-treated HT-29-Luc colon cancer cells, accompanying elevated levels of cleaved poly(ADP-ribose) polymerase, and caspase-3, −8 and −9. The expression levels of MCL1 apoptosis regulator BCL2 family member (Mcl-1) were decreased following addition of phloretin in colon cancer cells. In addition, overexpression of Mcl-1 in phloretin- and TRAIL-treated HT-29-Luc cells resulted in increased cell survival. Treatment of HT-29-Luc cells with a combination of cycloheximide (CHX) and phloretin led to a more prominent decrease in Mcl-1 expression compared with that in cells treated with CHX alone, while Mcl-1 expression was recovered by treatment with MG132. Binding of ubiquitin with Mcl-1 was verified using immunoprecipitation. Intraperitoneal injection of both TRAIL and phloretin into tumor xenografts was associated with a decreased tumor volume compared with that following injection with either TRAIL or phloretin. Overall, the present results suggest a synergistic effect of phloretin on TRAIL-induced apoptosis in colon cancer cells.

The Anti-Tumor Effect of Lactococcus lactis Bacteria-Secreting Human Soluble TRAIL Can Be Enhanced by Metformin Both In Vitro and In Vivo in a Mouse Model of Human Colorectal Cancer

Simple Summary

Colorectal cancer (CRC) is a major cause of morbidity and mortality in Europe, and accounts for over 10% of all cancer-related deaths worldwide. These indicate an urgent need for novel therapeutic options in CRC. Here, we analysed if genetically modified non-pathogenic Lactococcus lactis bacteria can be used for local delivery of human recombinant Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) and induction of tumor cells death in vitro and in vivo in CRC mouse model. We showed that modified L. lactis bacteria were able to secrete biologically active human soluble TRAIL (L. lactis(hsTRAIL+)), which selectively eliminated human CRC cells in vitro, and was further strengthened by metformin (MetF). Our results from in vitro studies were confirmed in vivo using subcutaneous NOD-SCID mouse model of human CRC. The data showed a significant reduction of the tumor growth by intratumor injection of L. lactis(hsTRAIL+) bacteria producing hsTRAIL. This effect could be further enhanced by oral administration of MetF.

Abstract

Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) induces apoptosis of many cancer cells, including CRC cells, being non-harmful for normal ones. However, recombinant form of human TRAIL failed in clinical trial when administered intravenously. To assess the importance of TRAIL in CRC patients, new form of TRAIL delivery would be required. Here we used genetically modified, non-pathogenic Lactococcus lactis bacteria as a vehicle for local delivery of human soluble TRAIL (hsTRAIL) in CRC. Operating under the Nisin Controlled Gene Expression System (NICE), the modified bacteria (L. lactis(hsTRAIL+)) were able to induce cell death of HCT116 and SW480 human cancer cells and reduce the growth of HCT116-tumor spheres in vitro. This effect was cancer cell specific as the cells of normal colon epithelium (FHC cells) were not affected by hsTRAIL-producing bacteria. Metformin (MetF), 5-fluorouracil (5-FU) and irinotecan (CPT-11) enhanced the anti-tumor actions of hsTRAIL in vitro. In the NOD-SCID mouse model, treatment of subcutaneous HCT116-tumors with L. lactis(hsTRAIL+) bacteria given intratumorally, significantly reduced the tumor growth. This anti-tumor activity of hsTRAIL in vivo was further enhanced by oral administration of MetF. These findings indicate that L. lactis bacteria could be suitable for local delivery of biologically active human proteins. At the same time, we documented that anti-tumor activity of hsTRAIL in experimental therapy of CRC can be further enhanced by MetF given orally, opening a venue for alternative CRC-treatment strategies.

Chemopreventive effect of α-hederin/carboplatin combination against experimental colon hyperplasia and impact on JNK signaling

Colon cancer is the commonest cancer worldwide. α-Hederin is a monodesmosidic triterpenoid saponin possessing diverse pharmacological activities. The running experiment was designed to test the chemopreventive activity of α-hederin when used as an adjuvant to carboplatin in an experimental model of mouse colon hyperplasia induced by 1,2-dimethylhydrazine (DMH). Fifty male Swiss albino mice were classified into five groups: group (I): saline group, group (II): DMH-induced colon hyperplasia control group, group (III): DMH + carboplatin (5 mg/kg) group, group (IV): DMH + α-hederin (80 mg/kg) group, and group (V): DMH + carboplatin (5 mg/kg)+α-hederin (80 mg/kg) group. Analyzing of colonic tissue indicated that the disease control group showed higher colon levels of phospho-PI3K to total-PI3K, phospho-AKT to total-AKT and cyclin D1 concurrent with lower phospho-JNK/total JNK ratio and caspase 3. However, treatment with α-hederin, in combination with carboplatin, favorably ameliorated phosphorylation of PI3K/AKT/JNK proteins, increased colon caspase 3 and downregulated cyclin D1. Microscopically, α-hederin, in combination with carboplatin, produced the most reduction in the histologic hyperplasia score, enhanced the goblet cell survival in periodic acid Schiff staining and reduced proliferation (Ki-67 immunostaining) in the current colon hyperplasia model. Collectively, the current study highlighted for the first time that using α-hederin as an adjuvant to carboplatin enhanced its chemopreventive activity, improved JNK signaling and increased apoptosis. Hence, further studies are warranted to test α-hederin as a promising candidate with chemotherapeutic agents in treating colon cancer.

Essential role of Salmonella Enteritidis DNA adenine methylase in modulating inflammasome activation

Background

Salmonella Enteritidis (SE) is one of the major foodborne zoonotic pathogens of worldwide importance which can induce activation of NLRC4 and NLRP3 inflammasomes during infection. Given that the inflammasomes play an essential role in resisting bacterial infection, Salmonella has evolved various strategies to regulate activation of the inflammasome, most of which largely remain unclear.

Results

A transposon mutant library in SE strain C50336 was screened for the identification of the potential factors that regulate inflammasome activation. We found that T3SS-associated genes invC, prgH, and spaN were required for inflammasome activation in vitro. Interestingly, C50336 strains with deletion or overexpression of Dam were both defective in activation of caspase-1, secretion of IL-1β and phosphorylation of c-Jun N-terminal kinase (Jnk). Transcriptome sequencing (RNA-seq) results showed that most of the differentially expressed genes and enriched KEGG pathways between the C50336-VS-C50336Δdam and C50336-VS-C50336::dam groups overlapped, which includes multiple signaling pathways related to the inflammasome. C50336Δdam and C50336::dam were both found to be defective in suppressing the expression of several anti-inflammasome factors. Moreover, overexpression of Dam in macrophages by lentiviral infection could specifically enhance the activation of NLRP3 inflammasome independently via promoting the Jnk pathway.

Conclusions

These data indicated that Dam was essential for modulating inflammasome activation during SE infection, there were complex and dynamic interplays between Dam and the inflammasome under different conditions. New insights were provided about the battle between SE and host innate immunological mechanisms.

FGD1 exhibits oncogenic properties in hepatocellular carcinoma through regulating cell morphology, autophagy and mitochondrial function

Faciogenital Dysplasia 1 (FGD1) has been involved in a variety of biological processes, including cytoskeleton restructuring, cell morphology, cell cycle progression, and cell polarity. Abnormal expression of FGD1 was also identified in several types of cancers, indicating its critical role in the development of cancers. However, little is known about the role of FGD1 in hepatocellular carcinoma (HCC). In this study, the expression of FGD1 in HCC was mined with the RNA sequencing data from the cancer genome atlas. By over-expressing or knocking down of FGD1, the effects of FGD1 on the malignant behavior of HCC were evaluated both in vitro and in vivo. We find that FGD1 is up-regulated in HCC and correlated with the development and prognosis of HCC. By over-expressing or knocking down of FGD1, the effects of FGD1 on the malignant behavior of HCC were evaluated both in vitro and in vivo. Knockdown of FGD1 remarkably inhibits the malignant behaviors and causes morphological disorder of pseudopodia, autophagy inhibition and mitochondrial dyfunction in HCC cells. Further investigation shows that Cdc42, a Rho GTPase, plays a role in these processes. Overexpression of FGD1 significantly promotes the oncogenic properties of HCC cells. Collectively, these findings reveal that FGD1 exhibits oncogenic properties in HCC through regulating cell morphology, autophagy and mitochondrial function, suggesting that FGD1 may serve as a potential therapeutic target for HCC.

The strong inhibitory effect of combining anti-cancer drugs AT406 and rocaglamide with blue LED irradiation on colorectal cancer cells

There is still no satisfying method to treat colorectal cancer (CRC) currently. Inspired by cocktail therapy, the combination of 465 nm blue LED irradiation and two multi-target anticancer agents AT406 and Rocaglamide has been investigated as an innovative way to treat colorectal cancer cells in vitro. It showed a strong inhibitory effect on colorectal cancer cells, and its side effects on human normal cells are negligible. When applied to HCT116 cells, it can achieve an apoptotic rate up to 95%. It is also seen to significantly inhibit proliferation of HT29 cells. Furthermore, little to no cell inhibition or damage of normal MRC-5 cells were seen after treatment. The combination of blue LED irradiation and two anti-cancer drugs causes apoptosis of colorectal cancer cells by activating the apoptotic pathway, inhibiting autophagy and proliferation pathways as well as the production of reactive oxygen species (ROS).

IRE1 signaling pathway mediates protective autophagic response against manganese-induced neuronal apoptosis in vivo and in vitro

Overexposure to manganese (Mn) can result in neurotoxicity and is associated with manganism, a Parkinson's-like neurological disorder. In addition, Mn can induce endoplasmic reticulum (ER) stress and autophagy. In this study, we used C57BL/6 mice to establish a model of manganism and found that Mn could induce cell injury. Our results also showed that Mn could initiate the unfolded protein response (UPR) signaling and autophagy, via initiation of the UPR signaling occurring earlier than autophagy. We further investigated the intrinsic relationship between the endoplasmic reticulum to nucleus 1(ERN1, also known as inositol requiring enzyme 1, IRE1) signaling pathway and autophagy induction in SH-SY5Y cells exposed to Mn. Our results revealed that autophagy activation was a protective response in Mn-induced toxicity. Additionally, we found that Jun N-terminal kinase (JNK) inhibition downregulated autophagy and interaction of c-Jun with the Beclin1 promoter. In addition, knockdown of IRE1 with the LV-IRE1 shRNA suppressed the expression of IRE1, TRAF2, p-ASK1, and p-JNK in Mn-treated SH-SY5Y cells. Furthermore, the expression of proteins associated with ASK1-TRAF2 complex formation and autophagy activation were reversed by the LV-IRE1 shRNA. These findings suggest that IRE1 was involved in the activation of JNK through the formation of the ASK1-TRAF2 complex, and JNK activation led to the induction of autophagy, which required Beclin1 transcription by c-Jun. In this study, we demonstrated that the IRE1 signaling pathway mediated the activation of JNK signaling via the formation of the ASK1-TRAF2 complex which could initiate autophagy and the protein c-Jun which regulates Beclin1 transcription in Mn-induced neurotoxicity.

ABCG2 Overexpression Contributes to Pevonedistat Resistance

MLN4924 (pevonedistat) is a first-in-class NEDD8-activating enzyme (NAE) inhibitor in clinical trials for the treatment of solid tumors and hematologic malignancies. Despite the promising activity of MLN4924 observed in early trials, drug resistance has been noted in some patients. Identifying the underlying cause of treatment failure may help to better stratify patients that are most likely to benefit from this novel agent. Early preclinical studies revealed that the development of NAE mutations promotes resistance to MLN4924. However, these mutations have not been detected in patients that are relapsed/refractory to MLN4924, suggesting that other mechanisms are driving clinical resistance. To better understand the potential mechanisms of MLN4924 resistance, we generated MLN4924-resistant ovarian cancer cells. Interestingly, these cells did not develop mutations in NAE. Transcriptome analyses revealed that one of the most upregulated genes in resistant cells was ABCG2. This result was validated by quantitative real-time PCR and immunoblotting. Importantly, the sensitivity of MLN4924-resistant cells was restored by lentiviral short hairpin RNA (shRNA) targeting ABCG2. Further investigation using ABCG2-overexpressing NCI-H460/MX20 cells determined that these cells are resistant to the anticancer effects of MLN4924 and can be sensitized by co-treatment with the ABCG2 inhibitors YHO-13351 and fumitremorgin C. Finally, HEK293 models with overexpression of wild-type ABCG2 (R482) and variants (R482G and R482T) all demonstrated significant resistance to MLN4924 compared to wild-type cells. Overall, these findings define an important molecular resistance mechanism to MLN4924 and demonstrate that ABCG2 may be a useful clinical biomarker that predicts resistance to MLN4924 treatment.

Colorectal Cancer Research: Basic, Preclinical, and Clinical Approaches

Colorectal cancer remains one of the deadliest cancers worldwide. It has become evident that further efforts in colorectal cancer research are required, from providing a better understanding of the cellular and molecular mechanisms leading to colorectal neoplasm initiation and progression from adenoma to metastasis, to generating reliable non-invasive detection tests for identifying lesions at early stages, as well as refining the current therapeutic and personalized approaches and developing new ones. The aim of this Special Issue is to cover all aspects of colorectal cancer research, including basic, preclinical, and clinical approaches.[...].

LncRNA LINC00662 promotes colon cancer tumor growth and metastasis by competitively binding with miR-340-5p to regulate CLDN8/IL22 co-expression and activating ERK signaling pathway

BACKGROUND

LncRNA LINC00662 is closely related to the occurrence and development of cancer. This study aims to explore the effect of LINC00662 on colon cancer tumor growth and metastasis and its molecular mechanism.

METHODS

CCK8, colony formation, transwell, scratch wound, TUNEL, flow cytometry, RT-PCR, western blotting and immunohistochemistry assays were used to detect the proliferation, apoptosis, invasion and migration of colon cancer cell and mRNA and protein expressions. Luciferase reporter and RNA pull down assays were used to detect the combination of LINC00662 and miR-340-5p or IL22 and the combination of miR-340-5p and CLDN8/IL22. Co-immunoprecipitation were used to detect the co-expression of CLDN8 and IL22 in colon cell lines. The targets of LINC00662 were predicated by Starbase v2.0. The target genes of miR-340-5p were predicated by miRDB and TargetScan. GO and KEGG enrichment analysis were performed by DAVID website.

RESULTS

LINC00662 was up-regulation in colon cancer tissues and cell lines. Univariate Cox regression analysis showed that the LINC00662 expression level was related to the poor prognosis. LINC00662-WT and miR-340-5p mimics co-transfection depressed luciferase activity and IL22/CLDN8-WT and miR-340-5p inhibitors co-transfection memorably motivated luciferase activity. LINC00662 overexpression promoted cell proliferation, invasion and migration, and inhibited cell apoptosis in colon cancer. In vivo xenograft studies in nude mice manifested that LINC00662 overexpression prominently accelerate tumor growth. There was an opposite reaction in the biological functions of colon cells and tumor growth between LINC00662 overexpression and LINC00662 inhibition in vitro and in vivo. The functions of miR-340-5p mimics regulating the biological functions of colon cells and tumor growth were consistent with those of LINC00662 inhibition. CLDN8 and IL22, as target genes of miR-340-5p, reversed the functions of LINC00662 affecting the biological functions of colon cells and the protein levels of Bax, Bcl-2, XIAP, VEGF, MMP-2, E-cadherin and N-cadherin. Co-immunoprecipitation experiments indicated that CLDN8 directly interact with IL22 in colon cell lines. LINC00662 regulated CLDN8 and IL22 expressions and the activation of ERK signaling pathway via targeting miR-340-5p.

CONCLUSION

LINC00662 overexpression promoted the occurrence and development of colon cancer by competitively binding with miR-340-5p to regulate CLDN8/IL22 co-expression and activating ERK signaling pathway.