Downregulation of miR-874-3p promotes chemotherapeutic resistance in colorectal cancer via inactivation of the Hippo signaling pathway

Identification and verification of m6A-related miRNAs correlated with prognosis and immune microenvironment in colorectal cancer

It's well known that N6-methyladenosine (m6A) modification is the most abundant modification in multiple RNA species. miRNAs play important roles in m6A modification and are closely related with occurrence and development of colorectal cancer (CRC). Thus, the aim of this study was to identify the prognostic value of m6A-related miRNAs and explore the correlation between the miRNAs and immune microenvironment in CRC. The differentially expressed m6A regulators and differentially expressed miRNAs between CRC tissues and adjacent normal tissues were identified based on TCGA dataset, and the m6A-related miRNAs were screened. The CRC patients from TCGA were randomized (1:1) into training set and validation set, and the risk score was established in the training set. Next, risk score was verified in the validation set and GSE92928 from GEO datasets. Besides, the relationship among tumor mutational burden, immune microenvironment and risk score were analyzed. What's more, RT-qPCR were used to explore the expression levels of the miRNAs in risk score between SW480 and SW620. A total of 29 m6A-related miRNAs were screened out, and a 5-differentially expressed miRNAs risk score was established. Kaplan-Meier analysis and ROC curves revealed the risk score could predict the prognosis of CRC, accurately. Similarly, the patients in the high-risk group had shorter overall survival in GSE92928. The risk score was relevant with the tumor mutational burden and immune infiltration, and the expression of HAVCR2 was significant difference between 2 risk groups. The expression levels of miR-328-3p, miR-3934-5p, miR-664b-5p and miR-3677-3p were down-regulated in SW620 compared with SW480, only the expression level of miR-200c-5p was up-regulated in SW620. The findings provided the new insights into the correlation between miRNAs and m6A regulators. The m6A-related miRNAs could predict the prognosis of CRC and provide the valuable information of immunotherapy in CRC patients.

Advances in understanding of role and mechanism of Hippo signaling pathway in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors, and most patients have a poor prognosis. Many studies have shown that the Hippo signaling pathway plays a key role in the occurrence and development of CRC by regulating CRC cell proliferation and apoptosis, tumor invasion and metastasis, autophagy, metabolic reprogramming, drug resistance, and other processes. This article reviews the latest progress in research of the expression of key molecules of the Hippo signaling pathway in CRC as well as the understanding of the mechanism by which this pathway regulates the occurrence and development of CRC.

Knockdown of circ_0004585 enhances the chemosensitivity of colorectal cancer cells to 5-fluorouracil via the miR-874-3p/CCND1 axis

BACKGROUND

Colorectal cancer (CRC) is a serious threat to human health and is drug-resistant. Circular RNA _0004585 (circ_0004585) has been shown to be expressed in CRC, but whether it plays a role in CRC with chemoresistance remains unknown. Therefore, this study aimed to investigate the potential role of circ_0004585 in CRC with 5-fluorouracil (5-FU) resistance.

METHODS

The expression of related genes was detected by quantitative real-time polymerase chain reaction (qRT-PCR), and the protein expressions of cleaved caspase-3, cleaved caspase-9, and cyclin D1 (CCND1) were detected by western blot. Cell functions were identified using CCK-8, colony formation, flow cytometry, tube formation and transwell assays. The putative relationships between miR-874-3p and circ_0004585 or CCND1 were validated by dual-luciferase reporter assays. Animal experiments were conducted to verify the effect of circ_0004585 on 5-FU resistance in vivo.

RESULTS

Circ_0004585 was highly expressed in CRC tissues and cells, particularly in 5-FU-resistant CRC tissues and cells. Circ_0004585 knockdown enhanced 5-FU sensitivity to further inhibit CRC cell viability, colony formation, cell migration and invasion, and accelerate cell apoptosis. MiR-874-3p was the target of circ_0004585, and miR-874-3p depletion partially recovered the malignant behaviors of 5-FU-resistant CRC cells that were blocked by silencing of circ_0004585. In addition, CCND1 was the target of miR-874-3p, and overexpression of CCND1 was able to restore the malignant effects of 5-FU-resistant CRC cells that were repressed by miR-874-3p enrichment. Animal experiments confirmed that circ_0004585 knockdown inhibited the growth of CRC tumors and enhanced 5-FU sensitivity in vivo.

CONCLUSION

Circ_0004585 promotes the development of CRC and increases 5-FU resistance in CRC through the miR-874-3p/CCND1 axis. These results suggest that circ_0004585 may be a therapeutic target for 5-FU-ressitant CRC.

Shikonin impedes type 2 ovarian cancer progression via FasL/caspase-8 and mir-874-3p/XIAP axis and prohibits the properties of stemness

Ovarian cancer is the most lethal gynecological cancer in women. Shikonin (SHK), derived from Lithospermum eryothrorhizon, can reduce cancer activity; however, its clinical effect on type 2 ovarian cancer cells remains undetermined. Here, we studied the effects of SHK on type 2 ovarian cancer using the KURAMOCHI, OVSAHO, CP70, and ascites E04 cell lines. The proliferation curve and half-maximal inhibitory concentration of SHK for the cell lines were evaluated using the second-generation tetrazolium dye assay and the cell viability were determined by the annexin V/PI as well as TUNEL assay. The caspase dependent pathway was performed by western blotting assay with pan-caspase inhibitor Z-VAD-FMK and SHK induced miR-874-3p expression thus suppressed anti-apoptosis markers XIAP and Bcl-xL. The effect of SHK on type 2 ovarian cancer cell migration and invasion was evaluated using the wound healing and transwell assays. Quantitative RT-PCR and western blot was used to evaluate cancer stem cell (CSC)-related gene/protein (OCT4, SOX2, NANOG, ALDH1, and C-MYC) expressions, sphere formation assay was executed and a xenograft animal model for in vivo antitumor effects of SHK. Taken together, Shikonin suppressed type 2 ovarian cancer cell viability, migration, and invasion abilities; decreased CSC-related markers expression as well as the sphere colony numbers. It also reduced the tumorigenicity of KURAMOCHI ALDH+ cells and induced anti-tumor effect in a xenograft model. Thus, SHK could contribute a potential therapeutic strategy on type 2 ovarian cancer cells via multiple functions.

Generation of TRIM28 Knockout K562 Cells by CRISPR/Cas9 Genome Editing and Characterization of TRIM28-Regulated Gene Expression in Cell Proliferation and Hemoglobin Beta Subunits

TRIM28 is a scaffold protein that interacts with DNA-binding proteins and recruits corepressor complexes to cause gene silencing. TRIM28 contributes to physiological functions such as cell growth and differentiation. In the chronic myeloid leukemia cell line K562, we edited TRIM28 using CRISPR/Cas9 technology, and the complete and partial knockout (KO) cell clones were obtained and confirmed using quantitative droplet digital PCR (ddPCR) technology. The amplicon sequencing demonstrated no off-target effects in our gene editing experiments. The TRIM28 KO cells grew slowly and appeared red, seeming to have a tendency towards erythroid differentiation. To understand how TRIM28 controls K562 cell proliferation and differentiation, transcriptome profiling analysis was performed in wild-type and KO cells to identify TRIM28-regulated genes. Some of the RNAs that encode the proteins regulating the cell cycle were increased (such as p21) or decreased (such as cyclin D2) in TRIM28 KO cell clones; a tumor marker, the MAGE (melanoma antigen) family, which is involved in cell proliferation was reduced. Moreover, we found that knockout of TRIM28 can induce miR-874 expression to downregulate MAGEC2 mRNA via post-transcriptional regulation. The embryonic epsilon-globin gene was significantly increased in TRIM28 KO cell clones through the downregulation of transcription repressor SOX6. Taken together, we provide evidence to demonstrate the regulatory network of TRIM28-mediated cell growth and erythroid differentiation in K562 leukemia cells.

Modulation of microRNAs and claudin-7 in Caco-2 cell line treated with Blastocystis sp., subtype 3 soluble total antigen

Background

Blastocystis sp., is a eukaryote of the large intestine, which is reported from almost all countries. The pathogenesis of this protist is not clear. The current study aimed to analyze the effects of Blastocystis sp., ST3 soluble total antigen (B3STA) on the microRNAs (miRNAs) involved in the gut permeability and also pro-inflammatory cytokines, occludin, and claudin-7.

Methods

Blastocystis sp., ST3 isolated from stool sample was purified, and its soluble total antigen was extracted using freeze and thawing. The Caco-2 cell line was treated with B3STA for 24 h and the expression levels of mir-16, mir-21, mir-29a, mir-223, and mir-874 were analyzed. In addition, the expression levels of il-8, il-15, occludin, and claudin-7 genes were assessed.

Results

B3STA significantly upregulated the expression of mir-223, and mir-874, and downregulated mir-29a. The expression of mir-16 and mir-21 was not significant. In addition, the expression of il-8 and il-15 was not significant. B3STA significantly decreased the expression level of claudin-7 (P-value < 0.0001), but the expression of occludin was not significant. Our results showed significant correlation between all studied miRNAs, except mir-29a, with downregulation of claudin-7.

Conclusions

This is the first study investigating the effects of Blastocystis sp., ST3 isolated from symptomatic subjects on the expression levels of miRNAs involved in the gut permeability. Our results demonstrated that B3STA may change miRNA expression, which are involved in the gut barrier integrity, and downregulates claudin-7, which is known as sealing factor.

miR-874: An Important Regulator in Human Diseases

miR-874 is located at 5q31.2, which is frequently deleted in cancer. miR-874 is downregulated in 22 types of cancers and aberrantly expressed in 18 types of non-cancer diseases. The dysfunction of miR-874 is not only closely related to the diagnosis and prognosis of tumor patients but also plays an important role in the efficacy of tumor chemotherapy drugs. miR-874 participates in the ceRNA network of long non-coding RNAs or circular RNAs, which is closely related to the occurrence and development of cancer and other non-cancer diseases. In addition, miR-874 is also involved in the regulation of multiple signaling pathways, including the Wnt/β-catenin signaling pathway, Hippo signaling pathway, PI3K/AKT signaling pathway, JAK/STAT signaling pathway, and Hedgehog signaling pathway. This review summarizes the molecular functions of miR-874 in the biological processes of tumor cell survival, apoptosis, differentiation, and tumorigenesis, and reveal the value of miR-874 as a cancer biomarker in tumor diagnosis and prognosis. Future work is necessary to explore the potential clinical application of miR-874 in chemotherapy resistance.

Investigating miRNA-mRNA interactions and gene regulatory networks from VTA dopaminergic neurons following perinatal nicotine and alcohol exposure using Bayesian network analysis

MicroRNAs play an important role in gene regulation for many biological systems, including nicotine and alcohol addiction. However, the underlying mechanism behind miRNAs and mRNA interaction is not well characterized. Microarrays are commonly used to quantify the expression levels of mRNAs and/or miRNAs simultaneously. In this study, we performed a Bayesian network analysis to identify mRNA and miRNA interactions following perinatal exposure to nicotine and/or alcohol. We utilized three sets of microarray data to predict the regulation relationship between mRNA and miRNAs. Following perinatal alcohol exposure, we identified two miRNAs: miR-542-5p and miR-874-3p, that exhibited a strong mutual influence on several mRNA in gene regulatory pathways, mainly Axon guidance and Dopaminergic synapses. Finally, we confirmed our predicted addiction pathways based on the Bayesian network analysis with the widely used Kyoto Encyclopedia of Genes and Genomes (KEGG)-based database and identified comparable relevant miRNA-mRNA pairs. We believe the Bayesian network can provide insight into the complexity biological process related to addiction and can potentially be applied to other diseases.

The Hippo signaling pathway in leukemia: function, interaction, and carcinogenesis

Cancer can be considered as a communication disease between and within cells; nevertheless, there is no effective therapy for the condition, and this disease is typically identified at its late stage. Chemotherapy, radiation, and molecular-targeted treatment are typically ineffective against cancer cells. A better grasp of the processes of carcinogenesis, aggressiveness, metastasis, treatment resistance, detection of the illness at an earlier stage, and obtaining a better therapeutic response will be made possible. Researchers have discovered that cancerous mutations mainly affect signaling pathways. The Hippo pathway, as one of the main signaling pathways of a cell, has a unique ability to cause cancer. In order to treat cancer, a complete understanding of the Hippo signaling system will be required. On the other hand, interaction with other pathways like Wnt, TGF-β, AMPK, Notch, JNK, mTOR, and Ras/MAP kinase pathways can contribute to carcinogenesis. Phosphorylation of oncogene YAP and TAZ could lead to leukemogenesis, which this process could be regulated via other signaling pathways. This review article aimed to shed light on how the Hippo pathway interacts with other cellular signaling networks and its functions in leukemia.

miR-874-3p mitigates cisplatin resistance through modulating NF-κB/inhibitor of apoptosis protein signaling pathway in epithelial ovarian cancer cells

The resistance to cisplatin, the most common platinum chemotherapy drug, may confine the efficacy of treatment in epithelial ovarian cancer patients. Aberrant expression of inhibitor of apoptosis proteins set the stage for resistance to cisplatin in EOC; besides, chemosensitivity in EOC can be chalked up to dysregulation of specific miRNAs. Herein, we investigated whether there is a potential correlation between miR-874-3p and the X-chromosome-linked inhibitor of apoptosis, a member of the IAP protein family in cisplatin-resistant EOC cells. The lower expression of miR-874-3p was found in SKOV3-DDP cells; it was also in association with cisplatin-resistance in EOC cells. XIAP was found to contribute to developing platinum resistance and is an authentic target for miR-874-3p in SKOV3-DDP cells. Consistently, restoration of miR-874-3p expression reversed cisplatin resistance in such cells by modulating XIAP and NF-κB/Survivin signaling pathway. Besides, siRNA knock down of XIAP in SKOV3-DDP cells had an anti-migratory effect like those with miR-874 overexpression. Importantly, the enforced expression of XIAP rescued SKOV3-DDP cells from the cytotoxic effects of miR-874-3p. Finally, miR-874-3p sensitized EOC cells to cisplatin-induced apoptosis, at least in part, through targeting XIAP. The cytotoxic effects of miR-874-3p can be attributed to the targeting XIAP in cisplatin-resistant EOC cells. We believe that the combination of cisplatin with miR-874-3p may make a potential strategy to reverse cisplatin resistance.

The direct miR-874-3p-target FAM84A promotes tumor development in papillary thyroid cancer

With the improvement in diagnostic technology, the incidence of thyroid cancer (TC) is on the rise. Papillary thyroid carcinoma (PTC) is the most common pathological type of thyroid cancer; therefore, it is important to explore some valuable molecular targets to improve the treatment and prognosis of PTC. Studies have shown that family with sequence similarity 84, member A (FAM84A) is involved in the development of various tumors. However, the role of FAM84A in PTC remains unknown. Herein, we explored the biological function and specific molecular mechanism of FAM84A in PTC. Results indicated that FAM84A was upregulated in PTC tissues and cells. In addition, patients with higher FAM84A expression tended to possess larger tumor size, higher lymph node metastasis rate, and advanced TNM stage. Further studies indicated that downregulation of FAM84A could inhibit the development of PTC in vitro and in vivo by repressing the epithelial–mesenchymal transition (EMT) and Wnt/β‐catenin signaling pathway. Moreover, FAM84A was confirmed to be negatively regulated by tumor suppressor miR‐874‐3p. In conclusion, our findings suggest that FAM84A may act as a potential diagnostic and therapeutic target for PTC.

The regulatory roles of long noncoding RNAs in osteoporosis

Osteoporosis is a common metabolic bone disease characterized by low bone mineral density (BMD) and microarchitectural deterioration of bone tissue, which leads to decreased bone strength and increased fracture risk. Osteoporosis mainly results from a disruption of the balance between bone formation mediated by osteoblasts and bone resorption mediated by osteoclasts. At present, the molecular mechanisms underlying osteoporosis are still not fully understood. Long noncoding RNAs (lncRNAs) are RNA molecules that exceed 200 nucleotides (nt) in length and have limited or no protein-coding capacity. Over the past decade, numerous lncRNAs have been demonstrated to participate in multiple biological processes and to play essential roles in the pathogenesis of various diseases. In this review, we summarize recent progress in research on lncRNAs in osteoporosis and mainly focus on their regulatory roles in osteogenesis and osteoclastogenesis. Moreover, we briefly discuss the potential clinical applications of lncRNAs in osteoporosis.

Molecular determinants of response to 5-fluorouracil-based chemotherapy in colorectal cancer: The undisputable role of micro-ribonucleic acids

5-flurouracil (5-FU)-based chemotherapy is the main pharmacological therapy for advanced colorectal cancer (CRC). Despite significant progress in the treatment of CRC during the last decades, 5-FU drug resistance remains the most important cause of failure in CRC therapy. Resistance to 5-FU is a complex and multistep process. Different mechanisms including microsatellite instability, increased expression level of key enzyme thymidylate synthase and its polymorphism, increased level of 5-FU-activating enzymes and mutation of TP53 are proposed as the main determinants of resistance to 5-FU in CRC cells. Recently, micro-ribonucleic acids (miRNA) and their alterations were found to have a crucial role in 5-FU resistance. In this regard, the miRNA-mediated mechanisms of 5-FU drug resistance reside among the new fields of pharmacogenetics of CRC drug response that has not been completely discovered. Identification of the biological markers that are related to response to 5-FU-based chemotherapy is an emerging field of precision medicine. This approach will have an important role in defining those patients who are most likely to benefit from 5-FU-based chemotherapy in the future. Thereby, the identification of 5-FU drug resistance mechanisms is an essential step to predict and eventually overcome resistance. In the present comprehensive review, we will summarize the latest knowledge regarding the molecular determinants of response to 5-FU-based chemotherapy in CRC by emphasizing the role of miRNAs.

Molecular mechanisms and clinical implications of miRNAs in drug resistance of colorectal cancer

Systemic chemotherapy is identified as a curative approach to prolong the survival time of patients with colorectal cancer (CRC). Although great progress in therapeutic approaches has been achieved during the last decades, drug resistance still extensively persists and serves as a major hurdle to effective anticancer therapy for CRC. The mechanism of multidrug resistance remains unclear. Recently, mounting evidence suggests that a great number of microRNAs (miRNAs) may contribute to drug resistance in CRC. Certain of these miRNAs may thus be used as promising biomarkers for predicting drug response to chemotherapy or serve as potential targets to develop personalized therapy for patients with CRC. This review mainly summarizes recent advances in miRNAs and the molecular mechanisms underlying miRNA-mediated chemoresistance in CRC. We also discuss the potential role of drug resistance-related miRNAs as potential biomarkers (diagnostic and prognostic value) and envisage the future orientation and challenges in translating the findings on miRNA-mediated chemoresistance of CRC into clinical applications.

LncRNA DCST1-AS1 regulates proliferation and apoptosis of rectal cancer cells by targeting miR-874-3p

BACKGROUND

Some long non-coding RNAs (lncRNAs) have been demonstrated to be abnormally expressed in rectal cancer (RC) and may be involved in tumorigenesis and development. The expression of lncRNA DCST1-AS1 is upregulated in tumors, but its mechanism of action in the development and progression of RC has not been elucidated. It was hypothesized that the expression level of DCST1-AS1 is increased in RC cells and it may promote tumorigenesis and development.

AIM

To investigate the effects of DCST1-AS1 on the proliferation and apoptosis of RC cells and the potential mechanism.

METHODS

The levels of DCST1-AS1 and miR-874-3p in 30 RC tissues and adjacent tissues were measured by quantitative real-time polymerase chain reaction. RC SW1463 cells were divided into different groups and transfected with si-NC, si-DCST1-AS1, miR-NC, miR-874-3p, pcDNA, pcDNA-DCST1-AS1, si-DCST1-AS1 + anti-miR-NC, and si-DCST1-AS1 + anti-miR-874-3p, respectively. The proliferation and apoptosis of SW1463 cells in each group were measured by MTT assay and flow cytometry, respectively. Western blot analysis was carried out to measure the expression levels of CyclinD1, p21, B-cell lymphoma-2 (Bcl-2), and Bcl-2-associated X protein (Bax) proteins in SW1463 cells. The targeting relationship between DCST1-AS1 and miR-874-3p was validated using a dual-luciferase reporter assay system.

RESULTS

Compared with tumor adjacent tissues, the level of lncRNA DCST1-AS1 in RC tissues was remarkably increased (P < 0.05), while the level of miR-874-3p was significantly decreased (P < 0.05). Compared with the si-NC and miR-NC groups, cell proliferation and CyclinD1 and Bcl-2 protein levels were reduced in the si-DCST1-AS1 group and miR-874-3p group, while the apoptosis rate and levels of p21 and Bax were increased. LncRNA DCST1-AS1 targeted and negatively regulated the expression of miR-874-3p. Compared with the si-DCST1-AS1 + anti-miR-NC group, cell proliferation and CyclinD1 and Bcl-2 protein levels in the si-DCST1-AS1 + anti-miR-874-3p group were increased, while cell apoptosis rate and p21 and Bax protein levels were decreased.

CONCLUSION

LncRNA DCST1-AS1 regulates the proliferation and apoptosis of SW1463 cells by targeting miR-874-3p. DCST1-AS1 may be a potential molecular target for RC.

Long non-coding RNA FER1L4 promotes osteogenic differentiation of human periodontal ligament stromal cells via miR-874-3p and vascular endothelial growth factor A

Background

Periodontal ligament stromal cells (PDLSCs) are ideal cell sources for periodontal tissue repair and regeneration, but little is known about what determines their osteogenic capacity. Long non-coding RNAs (lncRNAs) are important regulatory molecules at both transcriptional and post-transcriptional levels. However, their roles in the osteogenic differentiation of PDLSCs are still largely unknown.

Methods

The expression of lncRNA Fer-1-like family member 4 (FER1L4) during the osteogenic differentiation of PDLSCs was detected by quantitative reverse transcription polymerase chain reaction. Overexpression or knockdown of FER1L4 was used to confirm its regulation of osteogenesis in PDLSCs. Alkaline phosphatase and Alizarin red S staining were used to detect mineral deposition. Dual luciferase reporter assays were used to analyze the binding of miR-874-3p to FER1L4 and vascular endothelial growth factor A (VEGFA). Bone regeneration in critical-sized calvarial defects was assessed in nude mice. New bone formation was analyzed by micro-CT, hematoxylin and eosin staining, Masson’s trichrome staining, and immunohistochemical analyses.

Results

FER1L4 levels increased gradually during consecutive osteogenic induction of PDLSCs. Overexpression of FER1L4 promoted the osteogenic differentiation of PDLSCs, as revealed by alkaline phosphatase activity, Alizarin red S staining, and the expression of osteogenic markers, whereas FER1L4 knockdown inhibited these processes. Subsequently, we identified a predicted binding site for miR-874-3p on FER1L4 and confirmed a direct interaction between them. Wild-type FER1L4 reporter activity was significantly inhibited by miR-874-3p, whereas mutant FER1L4 reporter was not affected. MiR-874-3p inhibited osteogenic differentiation and reversed the promotion of osteogenesis in PDLSCs by FER1L4. Moreover, miR-874-3p targeted VEGFA, a crucial gene in osteogenic differentiation, whereas FER1L4 upregulated the expression of VEGFA. In vivo, overexpression of FER1L4 led to more bone formation compared to the control group, as demonstrated by micro-CT and the histologic analyses.

Conclusion

FER1L4 positively regulates the osteogenic differentiation of PDLSCs via miR-874-3p and VEGFA. Our study provides a promising target for enhancing the osteogenic potential of PDLSCs and periodontal regeneration.

Doublecotin-Like Kinase 1 Increases Chemoresistance of Colorectal Cancer Cells through the Anti-Apoptosis Pathway

Background

Colorectal Cancer (CRC) is the third most common cancer diagnosed and the second leading cause of cancer-related deaths in the United States. Cancer Stem Cells (CSCs) are believed to be the primary reason for the recurrence of CRC. Specific stem cell marker, doublecortin-like kinase 1 (DCLK1) plays critical roles in the tumorigenesis and progression of CRC. Up-regulation of DCLK1 is correlated with poor prognosis. Whether DCLK1 is correlated with enhanced chemoresistance of CRC cells is unclear. We aim to reveal the association of DCLK1 with chemoresistance of CRC cells and the underlying molecular mechanisms.

Methods

Stable DCLK1 over-expression cells (DCLK1+) were established using the HCT116 cells (WT). DCLK1+ and WT cells were treated with 5-Fluorouracil (5-Fu) at different doses for 24 or 48 hours. MTT assay was used to evaluate cell viability and IC50 of 5-Fu was determined. Quantitative real-time PCR was applied to determine the gene expression of caspase-3 (casp-3), casp-4, and casp-10. Cleaved casp-3 expression was investigated using Western blot and immunofluorescence.

Results

Our results demonstrated that IC50 of 5-Fu for the DCLK1+ cells was significantly higher than that of the WT cells for both 24 and 48-hour treatment (p=0.002 and 0.048 respectively), indicating increased chemoresistance of the DCLK1+ cells. Gene expression of casp-3, casp-4, and casp-10 were significantly inhibited in the DCLK1+ cells after 5-Fu treatment compared to the WT cells (p=7.616e-08, 1.575e-05 and 5.307e-08, respectively). Cleaved casp-3 amount and casp-3 positive cells were significantly decreased in the DCLK1+ cells after 5-Fu treatment compared to the WT cells (p=0.015).

Conclusions

In conclusion, our results demonstrated that DCLK1 overexpression enhanced the chemoresistance of CRC cells to 5-Fu treatment by suppressing gene expression of key caspases in the apoptosis pathway and activation of the apoptosis pathway. DCLK1 can be an intriguing therapeutic target for the effective treatment of CRC patients.

Analysis of the role of the Hippo pathway in cancer

Cancer is a serious health issue in the world due to a large body of cancer-related human deaths, and there is no current treatment available to efficiently treat the disease as the tumor is often diagnosed at a serious stage. Moreover, Cancer cells are often resistant to chemotherapy, radiotherapy, and molecular-targeted therapy. Upon further knowledge of mechanisms of tumorigenesis, aggressiveness, metastasis, and resistance to treatments, it is necessary to detect the disease at an earlier stage and for a better response to therapy. The hippo pathway possesses the unique capacity to lead to tumorigenesis. Mutations and altered expression of its core components (MST1/2, LATS1/2, YAP and TAZ) promote the migration, invasion, malignancy of cancer cells. The biological significance and deregulation of it have received a large body of interests in the past few years. Further understanding of hippo pathway will be responsible for cancer treatment. In this review, we try to discover the function of hippo pathway in different diversity of cancers, and discuss how Hippo pathway contributes to other cellular signaling pathways. Also, we try to describe how microRNAs, circRNAs, and ZNFs regulate hippo pathway in the process of cancer. It is necessary to find new therapy strategies for cancer.

YAP/TAZ Signaling and Resistance to Cancer Therapy

Drug resistance is a major challenge in cancer treatment. Emerging evidence indicates that deregulation of YAP/TAZ signaling may be a major mechanism of intrinsic and acquired resistance to various targeted and chemotherapies. Moreover, YAP/TAZ-mediated expression of PD-L1 and multiple cytokines is pivotal for tumor immune evasion. While direct inhibitors of YAP/TAZ are still under development, FDA-approved drugs that indirectly block YAP/TAZ activation or critical downstream targets of YAP/TAZ have shown promise in the clinic in reducing therapy resistance. Finally, BET inhibitors, which reportedly block YAP/TAZ-mediated transcription, present another potential venue to overcome YAP/TAZ-induced drug resistance.