MiR-214 sensitizes human colon cancer cells to 5-FU by targeting Hsp27

Heat Shock Proteins, a Double-Edged Sword: Significance in Cancer Progression, Chemotherapy Resistance and Novel Therapeutic Perspectives

Heat shock proteins (Hsps) are involved in one of the adaptive mechanisms protecting cells against environmental and metabolic stress. Moreover, the large role of these proteins in the carcinogenesis process, as well as in chemoresistance, was noticed. This review aims to draw attention to the possibilities of using Hsps in developing new cancer therapy methods, as well as to indicate directions for future research on this topic. In order to discuss this matter, a thorough review of the latest scientific literature was carried out, taking into account the importance of selected proteins from the Hsp family, including Hsp27, Hsp40, Hsp60, Hsp70, Hsp90 and Hsp110. One of the more characteristic features of all Hsps is that they play a multifaceted role in cancer progression, which makes them an obvious target for modern anticancer therapy. Some researchers emphasize the importance of directly inhibiting the action of these proteins. In turn, others point to their possible use in the design of cancer vaccines, which would work by inducing an immune response in various types of cancer. Due to these possibilities, it is believed that the use of Hsps may contribute to the progress of oncoimmunology, and thus help in the development of modern anticancer therapies, which would be characterized by higher effectiveness and lower toxicity to the patients.

Anti-tumor effect and mechanisms of Timosaponin AIII across diverse cancer progression

Timosaponin AIII (TAIII), a steroidal saponin derived from Anemarrhena asphodeloides Bunge, has gained attention for its versatile therapeutic properties. While well-established for its anti-inflammatory, antidepressant, and anticoagulant properties, emerging research highlights its potent anti-tumor capabilities. This review synthesizes recent findings on the intricate mechanisms and diverse functions of TAIII in cancer therapy, elucidating its impact on various tumor cells, encompassing the effects of TAIII on critical aspects of cancer progression, including metastasis, apoptosis, and autophagy. Additionally, the shared features of TAIII-induced anti-tumor activities, the factors contributing to the multifaceted anti-cancer activities of TAIII, and an exploration of the advantages and disadvantages associated with the regulation of multiple anti-tumor pathways by TAIII are discussed. Furthermore, the detailed regulation of signaling pathways is delineated and tailored to specific cancer types, providing a comprehensive overview of the potential development of TAIII as a promising anti-tumor agent.

Prognostic value of oxidative stress-related genes in colorectal cancer and its correlation with tumor immunity

Oxidative stress (OS) plays an essential role in chronic diseases such as colorectal cancer (CRC). In this study, we aimed to explore the relation between oxidative stress-related genes and CRC prognosis and their involvement in the immune microenvironment. Totally 101 OS-related genes were selected from the MsigDB database. Then, univariate Cox regression was used to explore the prognostic value of the selected genes correlated with the CRC patient survival in the TCGA database. A total of 9 prognostic OS-related genes in CRC were identified. Based on consensus clustering, CRC patients were then categorized into two molecular subtypes. A prognostic risk model containing 8 genes was established using Lasso regression, and CRC patients were divided into high or low-risk groups based on the median risk scores. The predictive value of the 8 genes in CRC prognosis was validated using ROC curves, which indicate that CTNNB1, STK25, RNF112, SFPQ, MMP3, and NOL3 were promising prognostic biomarkers in CRC. Furthermore, the immune cell infiltration levels in different risk groups or CRC subtypes were analyzed. We found that the high-risk or C1 subtype had immunosuppressive microenvironment, which might explain the unfavorable prognosis in the two groups of CRC patients. Additionally, functional experiments were conducted to investigate the effects of OS-related genes on CRC cell proliferation, stemness, and apoptosis. We found that CTNNB1, HSPB1, MMP3, and NOL3 were upregulated in CRC tissues and cells. Knockdown of CTNNB1, HSPB1, MMP3, and NOL3 significantly suppressed CRC cell proliferation, stemness and facilitated CRC cell apoptosis. In conclusion, we established prognostic CRC subtypes and an eight-gene risk model, which may provide novel prognostic indicators and benefit the design of individualized therapeutic strategies for CRC patients.

The Critical Function of microRNAs in Developing Resistance against 5- Fluorouracil in Cancer Cells

Although there have been significant advancements in cancer treatment, resistance and recurrence in patients make it one of the leading causes of death worldwide. 5-fluorouracil (5-FU), an antimetabolite agent, is widely used in treating a broad range of human malignancies. The cytotoxic effects of 5-FU are mediated by the inhibition of thymidylate synthase (TYMS/TS), resulting in the suppression of essential biosynthetic activity, as well as the misincorporation of its metabolites into RNA and DNA. Despite its huge benefits in cancer therapy, the application of 5-FU in the clinic is restricted due to the occurrence of drug resistance. MicroRNAs (miRNAs) are small, non-coding RNAs that act as negative regulators in many gene expression processes. Research has shown that changes in miRNA play a role in cancer progression and drug resistance. This review examines the role of miRNAs in 5-FU drug resistance in cancers.

HIF-1-Induced hsa-miR-429: Understanding Its Direct Targets as the Key to Developing Cancer Diagnostics and Therapies

MicroRNAs (miRNAs) play a critical role in the regulation of mRNA stability and translation. In spite of our present knowledge on the mechanisms of mRNA regulation by miRNAs, the utilization and translation of these ncRNAs into clinical applications have been problematic. Using hsa-miR-429 as an example, we discuss the limitations encountered in the development of efficient miRNA-related therapies and diagnostic approaches. The miR-200 family members, which include hsa-miR-429, have been shown to be dysregulated in different types of cancer. Although these miR-200 family members have been shown to function in suppressing epithelial-to-mesenchymal transition, tumor metastasis, and chemoresistance, the experimental results have often been contradictory. These complications involve not only the complex networks involving these noncoding RNAs, but also the problem of identifying false positives. To overcome these limitations, a more comprehensive research strategy is needed to increase our understanding of the mechanisms underlying their biological role in mRNA regulation. Here, we provide a literature analysis of the verified hsa-miR-429 targets in various human research models. A meta-analysis of this work is presented to provide better insights into the role of hsa-miR-429 in cancer diagnosis and any potential therapeutic approach.

MiR-214 Expression Is Elevated in Chronic Rhinosinusitis Mucosa and Regulates Lipopolysaccharide-Mediated Responses in Undifferentiated Human Nasal Epithelial Cell Culture

BACKGROUND

Chronic rhinosinusitis (CRS) is an inflammatory disorder of the upper airways. MicroRNAs (miRs) are reported to regulate several diverse physiological and pathological processes.

OBJECTIVE

This study aimed to evaluate the impact of miR-214 on lipopolysaccharide (LPS)-mediated inflammation, and mucin 5AC (MUC5AC) expression in human nasal epithelial cells.

METHODS

The expression of miR-214 was detected in CRS with polyps (CRSwNP) and CRS without polyps (CRSsNP) tissues. Cells were treated with LPS and a miR-214 inhibitor. The level of miR-214 was detected by quantitative real-time reverse transcriptase-PCR (qRT-PCR). The inflammatory cytokines (IL-6, IL-8, TNF, and IL-1β) and MUC5AC production were determined by qRT-PCR and ELISA. MUC5AC protein level was detected using western blot. Similarly, we determined the relationship between miR-214 and Sirtuin 1 (SIRT1) using the Dual luciferase activity assay.

RESULTS

miR-214 was increased in CRSwNP and CRSsNP tissues. LPS triggered the expression of miR-214, while miR-214 inhibition diminished the level of miR-214. MiR-214 inhibition prevented LPS-mediated the production of inflammatory cytokines. LPS treatment augmented MUC5AC mRNA, protein levels, and secretion, whereas miR-214 loss inhibited MUC5AC production in the presence of LPS. SIRT1 is a direct target of miR-214. Impairing SIRT1 by siRNA (siSIRT1) or EX527 (a selective SIRT1 inhibitor) reversed the effects of miR-214 inhibitor on inflammation and MUC5AC expression. Furthermore, miR-214 depression inhibited the STAT3/GDF15 pathway via targeting SIRT1. Upregulation of STAT3 or GDF15 partly abolished the anti-inflammatory roles of miR-214 inhibitor.

CONCLUSION

Taken together, miR-214 regulates LPS-mediated inflammation and MUC5AC expression via targeting SIRT1, and STAT3/GDF15 may involve in the regulation of miR-214 inhibitor on inflammation and MUC5AC expression.

Heat Shock Proteins: Central Players in Oncological and Immuno-Oncological Tracks

Heat shock proteins (HSPs) are a group of proteins that promote protein folding, inhibit denaturation of cellular proteins, and maintain other proteins' functional activities when cells are subjected to stress and/or high temperature. HSP classification is generally based on their molecular weights into large and small HSP. The family of small HSPs includes HSPs 27, 40, 60, 70, and 90. The potential roles of HSP27 and HSP70 are quite evident in different solid malignancies, including breast, colorectal, pancreatic, and liver cancers. In this chapter, the authors focus on HSP27 and HSP70 signaling in oncology and their role in different solid malignancies as well as they shed light on the novel role of HSP70 and HSP90 in the immune-oncology field.

Dual role of quercetin in enhancing the efficacy of cisplatin in chemotherapy and protection against its side effects: a review

Chemotherapy has opened a new window in cancer therapy. However, the resistance of cancer cells has dramatically reduced the efficacy of chemotherapy. Cisplatin is a chemotherapeutic agent and its potential in cancer therapy has been restricted by resistance of cancer cells. As a consequence, the scientists have attempted to find new strategies in elevating chemotherapy efficacy. Due to great anti-tumour activity, naturally occurring compounds are of interest in polychemotherapy. Quercetin is a flavonoid with high anti-tumour activity against different cancers that can be used with cisplatin to enhance its efficacy and also are seen to sensitise cancer cells into chemotherapy. Furthermore, cisplatin has side effects such as nephrotoxicity and ototoxicity. Administration of quercetin is advantageous in reducing the adverse effects of cisplatin without compromising its anti-tumour activity. In this review, we investigate the dual role of quercetin in enhancing anti-tumour activity of cisplatin and simultaneous reduction in its adverse effects.

Targeting the lncRNA FGD5-AS1/miR-497-5p/PD-L1 Axis Inhibits Malignant Phenotypes in Colon Cancer (CC)

Long noncoding RNAs (lncRNAs) regulate cancer progression and drug resistance. However, the role of lncRNA FGD5-AS1 in regulating colon cancer (CC) progression is still largely unknown. Hence, this study investigated the role of lncRNA FGD5-AS1 in regulating colon cancer (CC) progression and found that lncRNA FGD5-AS1 regulated miR-497-5p/PD-L1 axis to promote cancer progression in CC cells in vitro and in vivo. Specifically, we found that lncRNA FGD5-AS1 and PD-L1 tended to be high-expressed, while miR-497-5p was low-expressed in CC tissues and cell lines compared to the normal adjacent tissues and cells. Next, we found that lncRNA FGD5-AS1 positively regulated PD-L1 in CC cells by sponging miR-497-5p. Finally, our gain- and loss-of-function experiments evidenced that the lncRNA FGD5-AS1/miR-497-5p/PD-L1 axis regulates CC progression. Functionally, the data suggested that lncRNA FGD5-AS1 positively regulated while miR-497-5p negatively modulated malignant phenotypes, including cell proliferation, viability, invasion, migration, epithelial-mesenchymal transition (EMT), and tumorigenesis in CC cells. Interestingly, the inhibiting effects of lncRNA FGD5-AS1 ablation on CC development were abrogated by both silencing miR-497-5p and upregulating PD-L1. This study found that lncRNA FGD5-AS1 sponged miR-497-5p to upregulate PD-L1, resulting in CC progression, and provided novel agents for CC diagnosis and prognosis.

Perspectives of using microRNA-loaded nanocarriers for epigenetic reprogramming of drug resistant colorectal cancers

Epigenetic regulation by microRNAs (miRs) demonstrated a promising therapeutic potential of these molecules to regulate genetic activity in different cancers, including colorectal cancers (CRCs). The RNA-based therapy does not change genetic codes in tumor cells but can silence oncogenes and/or reactivate inhibited tumor suppressor genes. In many cancers, specific miRs were shown to promote or stop tumor progression. Among confirmed and powerful epigenetic regulators of colon carcinogenesis and development of resistance are onco-miRs, which include let-7, miR-21, miR-22, miR-23a, miR-27a, miR-34, miR-92, miR-96, miR-125b, miR-135b, miR-182, miR-200c, miR-203, miR-221, miR-421, miR-451, and others. Moreover, various tumor-suppressor miRs (miR-15b-5b, miR-18a, miR-20b, miR-22, miR-96, miR-139-5p, miR-145, miR-149, miR-197, miR-199b, miR-203, miR-214, miR-218, miR-320, miR-375-3p, miR-409-3p, miR-450b-5p, miR-494, miR-577, miR-874, and others) were found silenced in drug-resistant CRCs. Re-expression of tumor suppressor miR is complicated by the chemical nature of miRs that are not long-lasting compounds and require protection from the enzymatic degradation. Several recent studies explored application of miRs using nanocarrier complexes. This study critically describes the most successfully tested nanoparticle complexes used for intracellular delivery of nuclear acids and miRs, including micelles, liposomes, inorganic and polymeric NPs, dendrimers, and aptamers. Nanocarriers shield incorporated miRs and improve the agent stability in circulation. Attachment of antibodies and/or specific peptide or ligands facilitates cell-targeted miR delivery. Addressing in vivo challenges, a broad spectrum of non-toxic materials has been tested and indicated reliable advantages of lipid-based (lipoplexes) and polymer-based liposomes. Recent cutting-edge developments indicated that lipid-based complexes with multiple cargo, including several miRs, are the most effective approach to eradicate drug-resistant tumors. Focusing on CRC-specific miRs, this review provides a guidance and insights towards the most promising direction to achieve dramatic reduction in tumor growth and metastasis using miR-nanocarrier complexes.

microRNA-16-5p suppresses cell proliferation and angiogenesis in colorectal cancer by negatively regulating forkhead box K1 to block the PI3K/Akt/mTOR pathway

MicroRNAs (miRNAs/miRs) have aroused increasing attention in colorectal cancer (CRC) therapy. This study is designed for a detailed analysis of the roles of miR-16-5p and forkhead box K1 (FOXK1) in cell angiogenesis and proliferation during CRC in addition to their underlying mechanisms. CRC tissues and colon cancer cell lines (SW620 and HCT8) were investigated. qRT-PCR and Western blot were utilized to evaluate miR-16-5p and FOXK1 expression. Following gain- and loss-of-function assays on miR-16-5p or FOXK1, the effects of miR-16-5p and FOXK1 were assessed on cell angiogenesis and proliferation in CRC cells. A dual-luciferase reporter assay was employed to evaluate the binding relationship of miR-16-5p and FOXK1. Western blot was used to determine the effects of miR-16-5p and FOXK1 on key molecules of the PI3K/Akt/mTOR pathway. Highly expressed FOXK1 and lowly expressed miR-16-5p were observed in CRC cells and tissues. miR-16-5p overexpression or FOXK1 knockdown reduced CRC cell proliferation and angiogenesis of human umbilical vein endothelial cells co-cultured with the supernatant of CRC cells, whereas miR-16-5p silencing or FOXK1 upregulation caused opposite trends. Additionally, miR-16-5p negatively modulated FOXK1 expression. The blockade of the PI3K/Akt/mTOR pathway was triggered by miR-16-5p overexpression or FOXK1 silencing. In conclusion, miR-16-5p hampers cell angiogenesis and proliferation during CRC by targeting FOXK1 to block the PI3K/Akt/mTOR pathway.

The Role of Hsp27 in Chemotherapy Resistance

Heat shock protein (Hsp)-27 is a small-sized, ATP-independent, chaperone molecule that is overexpressed under conditions of cellular stress such as oxidative stress and heat shock, and protects proteins from unfolding, thus facilitating proteostasis and cellular survival. Despite its protective role in normal cell physiology, Hsp27 overexpression in various cancer cell lines is implicated in tumor initiation, progression, and metastasis through various mechanisms, including modulation of the SWH pathway, inhibition of apoptosis, promotion of EMT, adaptation of CSCs in the tumor microenvironment and induction of angiogenesis. Investigation of the role of Hsp27 in the resistance of various cancer cell types against doxorubicin, herceptin/trastuzumab, gemcitabine, 5-FU, temozolomide, and paclitaxel suggested that Hsp27 overexpression promotes cancer cell survival against the above-mentioned chemotherapeutic agents. Conversely, Hsp27 inhibition increased the efficacy of those chemotherapy drugs, both in vitro and in vivo. Although numerous signaling pathways and molecular mechanisms were implicated in that chemotherapy resistance, Hsp27 most commonly contributed to the upregulation of Akt/mTOR signaling cascade and inactivation of p53, thus inhibiting the chemotherapy-mediated induction of apoptosis. Blockage of Hsp27 could enhance the cytotoxic effect of well-established chemotherapeutic drugs, especially in difficult-to-treat cancer types, ultimately improving patients' outcomes.

The Combination of AHCC and ETAS Decreases Migration of Colorectal Cancer Cells, and Reduces the Expression of LGR5 and Notch1 Genes in Cancer Stem Cells: A Novel Potential Approach for Integrative Medicine

The AHCC standardized extract of cultured Lentinula edodes mycelia, and the standardized extract of Asparagus officinalis stem, trademarked as ETAS, are well known supplements with immunomodulatory and anticancer potential. Several reports have described their therapeutic effects, including antioxidant and anticancer activity and improvement of immune response. In this study we aimed at investigating the effects of a combination of AHCC and ETAS on colorectal cancer cells and biopsies from healthy donors to assess the possible use in patients with colorectal cancer. Our results showed that the combination of AHCC and ETAS was synergistic in inducing a significant decrease in cancer cell growth, compared with single agents. Moreover, the combined treatment induced a significant increase in apoptosis, sparing colonocytes from healthy donors, and was able to induce a strong reduction in migration potential, accompanied by a significant modulation of proteins involved in invasiveness. Finally, combined treatment was able to significantly downregulate LGR5 and Notch1 in SW620 cancer stem cell (CSC) colonospheres. Overall, these findings support the potential therapeutic benefits of the AHCC and ETAS combinatorial treatment for patients with colorectal cancer.

miR-138 Reduces the Dysfunction of T Follicular Helper Cells in Osteosarcoma via the PI3K/Akt/mTOR Pathway by Targeting PDK1

OBJECTIVE

To study the effect of miR-138 on the function of osteosarcoma (OS) T follicular helper cells (Tfh cells) and its mechanism.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from patients with osteosarcoma (OS group) and healthy volunteers (control group). CD4+CXCR5+ Tfh cells and CD9+ B cells were sorted by flow cytometry. qRT-PCR was used to detect the expression of miR-138 and PDK1 in the peripheral blood and CD4+CXCR5+ Tfh cells. Flow cytometry was employed to detect the proportion of CD4+CXCR5+ Tfh cells in CD4+ T cells, the level of CD40L in CD4+CXCR5+ Tfh cells, and the expression of CD27 and CD38 in B cells. Western blot was used to determine the protein expression of PDK1, PI3K, p-Akt, Akt, p-mTOR, and mTOR. In addition, dual-luciferase reporter assay was performed to verify the relationship between miR-138 and PDK1. ELISA method was used to determine the levels of IgM, IgG, IL-10, and IL-21.

RESULTS

Compared with that of the control group, the expression of miR-138 in PBMC and CD4+CXCR5+ Tfh cells of the OS group was lower; overexpression of miR-138 could promote the maturation of Tfh cells and immature B cells. The results of the dual-luciferase report experiment showed that miR-138 can target and negatively regulate PDK1, and PDK1 can reverse the effect of miR-138 on the function of Tfh cells and immature B cells.

CONCLUSION

miR-138 inhibits the PI3K/Akt/mTOR pathway by targeting and negatively regulating PDK1 to alleviate the dysfunction of T follicular helper cells in OS.

The role of non-coding RNAs in chemotherapy for gastrointestinal cancers

Gastrointestinal (GI) cancers, including colorectal, gastric, hepatic, esophageal, and pancreatic tumors, are responsible for large numbers of deaths around the world. Chemotherapy is the most common approach used to treat advanced GI cancer. However, chemoresistance has emerged as a critical challenge that prevents successful tumor elimination, leading to metastasis and recurrence. Chemoresistance mechanisms are complex, and many factors and pathways are involved. Among these factors, non-coding RNAs (ncRNAs) are critical regulators of GI tumor development and subsequently can induce resistance to chemotherapy. This occurs because ncRNAs can target multiple signaling pathways, affect downstream genes, and modulate proliferation, apoptosis, tumor cell migration, and autophagy. ncRNAs can also induce cancer stem cell features and affect the epithelial-mesenchymal transition. Thus, ncRNAs could possibly act as new targets in chemotherapy combinations to treat GI cancer and to predict treatment response.

Knockdown of microRNA-214-3p Promotes Tumor Growth and Epithelial-Mesenchymal Transition in Prostate Cancer

Simple Summary

Prostate Cancer is the second leading cause of cancer-related deaths in the United States. In this study, we analyzed a molecule known as a microRNA, which regulates the expression of genes. microRNAs are involved in processes related to cancer onset and progression. Abnormal expression of microRNAs can promote prostate cancer. This study showed that knockdown of microRNA miR-214-3p enhanced the progression and of prostate cancer. In addition, miR-214 regulated the expression of many genes. These results are useful to better understand the function of miR-214-3p in prostate cancer and can be a useful target in the treatment of the disease.

Abstract

Abnormal expression of microRNA miR-214-3p (miR-214) is associated with multiple cancers. In this study, we assessed the effects of CRISPR/Cas9 mediated miR-214 depletion in prostate cancer (PCa) cells and the underlying mechanisms. Knockdown of miR-214 promoted PCa cell proliferation, invasion, migration, epithelial-mesenchymal transition (EMT), and increased resistance to anoikis, a key feature of PCa cells that undergo metastasis. The reintroduction of miR-214 in miR-214 knockdown cells reversed these effects and significantly suppressed cell proliferation, migration, and invasion. These in vitro studies are consistent with the role of miR-214 as a tumor suppressor. Moreover, miR-214 knockout increased tumor growth in PCa xenografts in nude mice supporting its anti-oncogenic role in PCa. Knockdown of miR-214 increased the expression of its target protein, Protein Tyrosine Kinase 6 (PTK6), a kinase shown to promote oncogenic signaling and tumorigenesis in PCa. In addition, miR-214 modulated EMT as exhibited by differential regulation of E-Cadherin, N-Cadherin, and Vimentin both in vitro and in vivo. RNA-seq analysis of miR-214 knockdown cells revealed altered gene expression related to PCa tumor growth pathways, including EMT and metastasis. Collectively, our findings reveal that miR-214 is a key regulator of PCa oncogenesis and is a potential novel therapeutic target for the treatment of the disease.

TBHQ attenuates ferroptosis against 5-fluorouracil-induced intestinal epithelial cell injury and intestinal mucositis via activation of Nrf2

BACKGROUND

Intestinal mucositis is a common side effect of chemotherapy and radiotherapy. Very few drugs can efficiently ameliorate it. Tertiary butylhydroquinone (TBHQ) is a widely used food preservative with known immunomodulatory activity. Whether it has an effect on intestinal mucositis remains unknown. In this study, we investigated the role and mechanism of action of TBHQ on 5-fluorouracil-induced (5-FU-induced) human intestinal epithelial cell (HIEC) injury and intestinal mucositis in mice.

METHODS

We established a cell model of HIEC injury and a mouse model of intestinal mucositis via treatment with 5-FU. Cell death, Cell Counting Kit-8, and lactate dehydrogenase (LDH) release were assessed for the HIECs. Diarrhea, body weight, intestinal length, mucosal damage, and the levels of IL-6, TNF-α, IL-1β, glutathione, reactive oxygen species, and malondialdehyde were determined for the mice. Additionally, we performed immunohistochemical analysis, immunofluorescence, western blotting, quantitative real-time PCR, and ELISA to examine the effects of TBHQ. Finally, HIECs were transfected with an Nrf2 gene silencer to verify its role in ferroptosis. All data were analyzed using one-way analysis of variance or paired t-tests.

RESULTS

TBHQ markedly decreased LDH release and cell death and improved the proliferative ability of 5-FU-treated HIECs. The TBHQ-treated mice showed reduced weight loss, a lower diarrhea score, and longer colons than the 5-FU-treated mice. The in vivo expressions of IL-1β, IL-6, and TNF-α were suppressed by TBHQ treatment. Ferroptosis was shown to be involved in 5-FU-induced intestinal mucositis, and TBHQ markedly hampered its activation. Mechanistically, TBHQ activated Nrf2 effectively and selective Nrf2 knockdown significantly reduced the anti-ferroptotic functions of TBHQ in 5-FU-treated HIECs.

CONCLUSIONS

TBHQ attenuates ferroptosis in 5-FU-induced intestinal mucositis, making it a potential novel protective agent against intestinal mucositis.

Ins and Outs of Heat Shock Proteins in Colorectal Carcinoma: Its Role in Carcinogenesis and Therapeutic Perspectives

Cancer cells can reprogram their metabolic activities and undergo uncontrolled proliferation by utilizing the power of heat shock proteins (HSPs). HSPs are highly conserved chaperones that facilitate the folding of intracellular proteins under stress. Constitutively, HSPs are expressed at low levels, but their expression upregulates in response to a wide variety of insults, including anticancer drugs, allowing cancer cells to develop chemoresistance. In recent years, several researchers have reported that HSPs could be an important therapeutic target in difficult-to-treat cancers such as colorectal carcinoma (CRC). Worldwide, CRC is the second most common type of cancer and the second leading cause of cancer-related deaths. The molecular complexity of CRC and the coexisting inflammatory conditions present a significant obstacle to developing effective treatment. Recently, considerable progress has been made in enhancing our understanding of the role of HSPs in CRC pathogenesis. Moreover, novel therapeutic strategies targeting HSPs, either alone or in combination with other anticancer agents, have been reported. Herein, we present an overview of the functional mechanisms and the diagnostic and prognostic potential of HSPs in CRC. We also discuss emerging anti-CRC strategies based on targeting HSPs.

Recent Updates on Mechanisms of Resistance to 5-Fluorouracil and Reversal Strategies in Colon Cancer Treatment

5-Fluorouracil (5-FU) plus leucovorin (LV) remain as the mainstay standard adjuvant chemotherapy treatment for early stage colon cancer, and the preferred first-line option for metastatic colon cancer patients in combination with oxaliplatin in FOLFOX, or irinotecan in FOLFIRI regimens. Despite treatment success to a certain extent, the incidence of chemotherapy failure attributed to chemotherapy resistance is still reported in many patients. This resistance, which can be defined by tumor tolerance against chemotherapy, either intrinsic or acquired, is primarily driven by the dysregulation of various components in distinct pathways. In recent years, it has been established that the incidence of 5-FU resistance, akin to multidrug resistance, can be attributed to the alterations in drug transport, evasion of apoptosis, changes in the cell cycle and DNA-damage repair machinery, regulation of autophagy, epithelial-to-mesenchymal transition, cancer stem cell involvement, tumor microenvironment interactions, miRNA dysregulations, epigenetic alterations, as well as redox imbalances. Certain resistance mechanisms that are 5-FU-specific have also been ascertained to include the upregulation of thymidylate synthase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, and the downregulation of thymidine phosphorylase. Indeed, the successful modulation of these mechanisms have been the game plan of numerous studies that had employed small molecule inhibitors, plant-based small molecules, and non-coding RNA regulators to effectively reverse 5-FU resistance in colon cancer cells. It is hoped that these studies would provide fundamental knowledge to further our understanding prior developing novel drugs in the near future that would synergistically work with 5-FU to potentiate its antitumor effects and improve the patient's overall survival.

Expression of miR-92a in colon cancer tissues and its correlation with clinicopathologic features and prognosis

OBJECTIVE

This study analyzed the expression of miR-92a in colon tumor tissues and its correlation with disease clinicopathologic features and prognosis.

METHODS

83 cases of colorectal cancer tissues and paracancerous normal tissues acquired from colon cancer resection surgery during January 2015-January 2017 were collected. We detected the expression of miR-92a in cancer tissues and paracancerous tissues by qRT-PCR, and analyzed the correlation between the relative expression of miR-92 in colon cancer tissues and clinicopathologic characteristics, progression-free survival (PFS), and overall survival (OS) of the patients accordingly.

RESULTS

The relative expression level of miR-92a in colon cancer tissues was higher than of paracancerous tissues (P<0.05). Relative expression of miR-92a in cancer was correlated with the degree of differentiation, TNM stage, and lymph node metastasis (P<0.05), while uncorrelated with gender, age, tumor diameter, or invasion depth (P>0.05). Patients with low expression of miR-92a had superior PFS to the control group (P>0.05) and better OS (P<0.05).

CONCLUSION

Abnormally high expression of miR-92a occurs in colon tumor tissues. Its expression is related to the occurrence, progression, and prognosis of patients with colon cancer. It may be a marker for diagnosis, treatment, and prognosis of disease.

MicroRNA-29b-3p promotes 5-fluorouracil resistance <em>via</em> suppressing TRAF5-mediated necroptosis in human colorectal cancer

Drug resistance in colorectal cancer is a great challenge in clinic. Elucidating the deep mechanism underlying drug resistance will bring much benefit to diagnosis, therapy and prognosis in patients with colorectal cancer. In this study, miR-29b-3p was shown to be involved in resistance to 5-fluorouracil (5-FU)-induced necroptosis of colorectal cancer. Further, miR-29b-3p was shown to target a regulatory subunit of necroptosis TRAF5. Rescue of TRAF5 could reverse the effect of miR-29b-3p on 5-FU-induced necroptosis, which was consistent with the role ofnecrostatin-1 (a specific necroptosis inhibitor). Then it was demonstrated that miR-29b-3p was positively correlated with chemo-resistance in colorectal cancer while TRAF5 negatively. In conclusion, it is deduced that miR-29b-3p/TRAF5 signaling axis plays critical role in drug resistance in chemotherapy for colorectal cancer patients by regulating necroptosis. The findings in this study provide us a new target for interfere therapy in colorectal cancer.

Down-regulation of lncRNA DNAJC3-AS1 inhibits colon cancer via regulating miR-214-3p/LIVIN axis

Long non-coding RNAs (lncRNAs) play a key role in the development and metastasis of cancer. However, the biological role and clinical significance of lncRNA DNAJC3-AS1 in the development of colon cancer is still unknown. In this study, the effects of DNAJC3-AS1 on cell proliferation, migration, and invasion were evaluated by MTT assay, wound-healing assay, and transwell assay, respectively. The relationship between DNAJC3-AS1, miR-214-3p and LIVIN was predicted by the online software and confirmed by dual-luciferase reporter assay. We found that the down-regulation of DNAJC3-AS1 inhibited the proliferation of colon cancer cells and induced growth arrest. Down-regulation of DNAJC3-AS1 also inhibited the migration, invasion, and epithelial-mesenchymal transition (EMT) of colon cancer cells. Moreover, miR-214-3p can bind to DNAJC3-AS1, and knockdown of DNAJC3-AS1 increased miR-214-3p expression in colon cancer cells. LIVIN was identified as a target of miR-214-3p. The up-regulation of miR-214-3p inhibited the protein expression of LIVIN and suppressed the activation of the NF-κB signaling pathway. Besides, down-regulation of DNAJC3-AS1 reduced cell viability, invasion, and EMT of colon cancer cells, while miR-214-3p inhibitor could reverse these effects. The expression of LIVIN and the activation of the NF-κB signaling pathway were suppressed by down-regulating DNAJC3-AS1, while these effects could be restored by miR-214-3p inhibitor. These findings suggested that DNAJC3-AS1 may promote colon cancer progression by regulating the miR-214-3p/LIVIN axis. DNAJC3-AS1 may serve as a new biomarker and therapeutic target for colon cancer, stimulating new research directions and treatment options.

JNK pathway and heat shock response mediate the survival of C26 colon carcinoma bearing mice fed with the mushroom Pleurotus eryngii var. eryngii without affecting tumor growth or cachexia

In the last few years, there has been emerging interest in developing treatments against human diseases using natural bioactive content. Here, the powder of the edible mushroom Pleurotus eryngii var. eryngii was mixed with the normal diet of mice bearing C26 colon carcinoma. Interestingly, it was evidenced by a significant increase in the survival rate of C26 tumor-bearing mice accompanied by a significant increase in Hsp90 and Hsp27 protein levels in the tumors. These data were paralleled by a decrease in Hsp60 levels. The mushroom introduced in the diet induced the inhibition of the transcription of the pro-inflammatory cytokines IL-6 and IL-1 exerting an anti-inflammatory action. The effects of the mushroom were mediated by the activation of c-Jun NH₂-terminal kinases as a result of metabolic stress induced by the micronutrients introduced in the diet. In the tumors of C26 bearing mice fed with Pleurotus eryngii there was also a decreased expression of the mitotic regulator survivin and the anti-apoptotic factor Bcl-xL as well as an increase in the expression levels of Atg7, a protein that drives autophagy. In our hypothesis the interplay of these molecules favored the survival of the mice fed with the mushroom. These data are promising for the introduction of Pleurotus eryngii as a dietary supplement or as an adjuvant in anti-cancer therapy.

The Combination Therapy of Fluorouracil and Oxaliplatin Suppress the Progression of Colon Cancer Through miR-183-5p/SOCS3 Axis and Downregulating PD-L1

Purpose

The purpose of this study was to investigate the mechanism of combination of fluorouracil (FU) and oxaliplatin (OXA) on the progression of colon cancer via miR-183-5p/SOCS3 axis and regulating PD-L1.

Methods

HCT116 cells were treated with 4 μM OXA and 10.5 μM FU, or exogenous regulation of the expression of miR-183-5p, SOCS3 and PD-L1 in HCT116 cells. CCK-8 assay was employed to detect cell viability of HCT116 cells. Flow cytometry was performed to assess the apoptosis and cell cycle. The expression level of SOCS3, PD-L1, chemokines (CCL1, CCL4 and CCL7) and immune escapes related proteins (EGFR, STARD1 and STARD3) in HCT116 cells were assessed by Western blotting. In addition, dual-luciferase reporter gene was carried out to verify the targeted relationship between miR-183-5p with SOCS3.

Results

Our study demonstrated that the combination of OXA and FU remarkably suppressed proliferation, promoted apoptosis and arrest cells in G0/G1 phrase of HCT116 cells, and observably downregulated the expression of PD-L1, CCL1, CCL4, CCL7, EGFR, STARD1 and STARD3. Meanwhile, the combination of OXA and FU significantly downregulated miR-183-5p expression. Knockdown of miR-183-5p also repressed the proliferation, promoted apoptosis and arrest cells in G0/G1 phrase of HCT116 cells, and downregulated the expression of PD-L1, CCL1, CCL4, CCL7, EGFR, STARD1 and STARD3. In addition, our study proved that miR-183-5p upregulated PD-L1 by targeting downregulated SOCS3 expression. Finally, we demonstrated that the combination therapy of OXA and FU inhibited the proliferation, promote apoptosis and arrest cells in G0/G1 phrase by downregulating PD-L1 via miR-183-5p/SOCS3 axis.

Conclusion

The combination therapy of OXA and FU could suppress the malignant biological behavior, and the mechanism was realized by inhibiting PD-L1 through miR-183-5p/SOCS3 axis.

Exosomal Long Non-coding RNA HOTTIP Increases Resistance of Colorectal Cancer Cells to Mitomycin via Impairing MiR-214-Mediated Degradation of KPNA3

It has been reported that long non-coding RNA HOXA distal transcript antisense RNA (lncRNA HOTTIP) functions as a tumor promoter in colorectal cancer (CRC). Hence, we paid attention to exploring whether exosomes could carry lncRNA HOTTIP to affect the mitomycin resistance in CRC and to identify the underlying mechanisms. High expression of HOTTIP was detected in mitomycin-resistant CRC cells. Inhibition of HOTTIP reduced the mitomycin resistance. In the co-culture system of mitomycin-resistant cells or their derived exosomes with CRC cells, the HOTTIP was found to be transferred into the parental cells via extracellular vesicles (EVs) secreted from mitomycin-resistant cells and to contribute to the mitomycin resistance. Based on the bioinformatics databases, possible interaction network of HOTTIP, microRNA-214 (miR-214) and Karyopherin subunit alpha 3 (KPNA3) in CRC was predicted, which was further analyzed by dual-luciferase reporter, RNA binding protein immunoprecipitation and RNA pull-down assays. As HOTTIP down-regulated miR-214 to elevate the KPNA3 expression, HOTTIP enhanced the mitomycin resistance through impairing miR-214-dependent inhibition of KPNA3. Finally, HOTTIP was suggested as an independent factor predicting mitomycin response in patients with CRC. Those data together confirmed the promotive effects of EV-carried HOTTIP on the mitomycin resistance, while targeting HOTTIP might be a promising strategy overcoming drug resistance in CRC.

Epithelial-Mesenchymal Transition and MicroRNAs in Colorectal Cancer Chemoresistance to FOLFOX

The FOLFOX scheme, based on the association of 5-fluorouracil and oxaliplatin, is the most frequently indicated chemotherapy scheme for patients diagnosed with metastatic colorectal cancer. Nevertheless, development of chemoresistance is one of the major challenges associated with this disease. It has been reported that epithelial-mesenchymal transition (EMT) is implicated in microRNA-driven modulation of tumor cells response to 5-fluorouracil and oxaliplatin. Moreover, from pharmacogenomic research, it is known that overexpression of genes encoding dihydropyrimidine dehydrogenase (DPYD), thymidylate synthase (TYMS), methylenetetrahydrofolate reductase (MTHFR), the DNA repair enzymes ERCC1, ERCC2, and XRCC1, and the phase 2 enzyme GSTP1 impair the response to FOLFOX. It has been observed that EMT is associated with overexpression of DPYD, TYMS, ERCC1, and GSTP1. In this review, we investigated the role of miRNAs as EMT promotors in tumor cells, and its potential effect on the upregulation of DPYD, TYMS, MTHFR, ERCC1, ERCC2, XRCC1, and GSTP1 expression, which would lead to resistance of CRC tumor cells to 5-fluorouracil and oxaliplatin. This constitutes a potential mechanism of epigenetic regulation involved in late-onset of acquired resistance in mCRC patients under FOLFOX chemotherapy. Expression of these biomarker microRNAs could serve as tools for personalized medicine, and as potential therapeutic targets in the future.

Low miR-1273a expression predicts poor prognosis of colon cancer and facilitates tumor cell proliferation, migration, and invasion

MicroRNAs (miRNAs) have been indicated to be frequently dysregulated in various cancers and promising biomarkers for colon cancer. The present study aimed to assess the prognostic significance and biological function of miR-1273a in colon cancer. The expression levels of miR-1273a was estimated using quantitative real-time polymerase chain reaction. Kaplan-Meier survival curves and Cox regression analysis were used to evaluate the prognostic value of miR-1273a in patients of colon cancer. The effects of miR-1273a on cell proliferation, migration, and invasion were investigated by cell experiments. The expression of miR-1273a was downregulated in colon cancer tissues and tumor cell lines compared with the normal controls (all P<0.001). The aberrant expression of miR-1273a was associated with vascular invasion (P=0.005), differentiation (P=0.023), lymph node metastasis (P=0.021), and TNM stage (P=0.004). The patients with low miR-1273a expression had low overall survival compared with the patients with high miR-1273a expression (log-rank P=0.002). miR-1273a was detected to be an independent prognostic biomarker for patients. Furthermore, the results of cell experiments revealed that miR-1273a downregulation promoted, while miR-1273a upregulation suppressed the cell proliferation, migration, and invasion. In conclusion, all data indicated that a downregulated expression of miR-1273a predicted poor prognosis for colon cancer and enhanced tumor cell proliferation, migration, and invasion. Thus, we suggest that methods to promote miR-1273a expression may serve as novel therapeutic strategies in colon cancer.

MicroRNA-214-3p targets the PLAGL2-MYH9 axis to suppress tumor proliferation and metastasis in human colorectal cancer

Evidence has shown that microRNAs (miRNAs) participate in the progression of CRC. Previous studies have indicated that miR-214-3p is abnormally expressed in various malignant tumors. However, the biological function it plays in CRC and the potential mechanism are unclear. Here, we demonstrated that miR-214-3p was obviously downregulated in CRC. Moreover, we found a strong correlation between the miR-214-3p level and tumor size and lymphatic metastasis. Furthermore, when miR-214-3p was decreased by an Lv-miR-214-3p inhibitor, the proliferation and migration of SW480 and HCT116 cells were significantly increased. As expected, the ability of proliferation and migration was significantly suppressed when miR-214-3p was overexpressed in DLD1 cells. According to the dual-luciferase reporter results, PLAGL2 was found to be a direct downstream molecule of miR-214-3p. Chromatin immunoprecipitation (CHIP) confirmed that MYH9, a well-known cytoskeleton molecule in CRC, was a direct targeting gene of PLAGL2. Silencing PLAGL2 or MYH9 could reverse the effect of a miR-214-3p inhibitor on CRC cells. In summary, our studies proved that low expression of miR-214-3p and overexpression of downstream PLAGL2 in CRC indicated a poor prognosis. MiR-214-3p suppressed the malignant behaviors of colorectal cancer by regulating the PLAGL2/MYH9 axis. MiR-214-3p might be a novel therapeutic target or prognostic marker for CRC.

Editorial focus: understanding off-target effects as the key to successful RNAi therapy

With the first RNA interference (RNAi) drug (ONPATTRO (patisiran)) on the market, we witness the RNAi therapy field reaching a critical turning point, when further improvements in drug candidate design and delivery pipelines should enable fast delivery of novel life changing treatments to patients. Nevertheless, ignoring parallel development of RNAi dedicated in vitro pharmacological profiling aiming to identify undesirable off-target activity may slow down or halt progress in the RNAi field. Since academic research is currently fueling the RNAi development pipeline with new therapeutic options, the objective of this article is to briefly summarize the basics of RNAi therapy, as well as to discuss how to translate basic research into better understanding of related drug candidate safety profiles early in the process.

Epigenetic Alterations of Heat Shock Proteins (HSPs) in Cancer

Heat shock proteins (HSPs) are associated with various physiological processes (protein refolding and degradation) involved in the responses to cellular stress, such as cytotoxic agents, high temperature, and hypoxia. HSPs are overexpressed in cancer cells and play roles in their apoptosis, invasion, proliferation, angiogenesis, and metastasis. The regulation or translational modification of HSPs is recognized as a therapeutic target for the development of anticancer drugs. Among the regulatory processes associated with HSP expression, the epigenetic machinery (miRNAs, histone modification, and DNA methylation) has key functions in cancer. Moreover, various epigenetic modifiers of HSP expression have also been reported as therapeutic targets and diagnostic markers of cancer. Thus, in this review, we describe the epigenetic alterations of HSP expression in cancer cells and suggest that HSPs be clinically applied as diagnostic and therapeutic markers in cancer therapy via controlled epigenetic modifiers.