Let‐7e enhances the radiosensitivity of colorectal cancer cells by directly targeting insulin‐like growth factor 1 receptor

Upregulated let-7 expression in the follicular fluid of patients with endometriomas leads to dysfunction of granulosa cells through targeting of IGF1R

STUDY QUESTION

What molecular mechanisms underlie the decline in ovarian reserve as the number and quality of oocytes decrease in patients with ovarian endometriomas (OEM)?

SUMMARY ANSWER

Elevated expression of the let-7 micro(mi)RNAs in the follicular microenvironment of OEM-affected ovaries targets the expression of type 1 insulin-like growth factor receptor (IGF1R) in granulosa cell (GC) and disrupts their proliferation, steroid hormone secretion levels, adenosine triphosphate (ATP) energy metabolism, and reactive oxygen species (ROS) oxidative stress levels.

WHAT IS KNOWN ALREADY

Patients with OEM exhibit diminished ovarian reserve, characterized by reduced oocyte quantity and quality. Fibrotic changes in the ovarian tissue surrounding the OEM create a disruptive microenvironment for follicular growth and development.

STUDY DESIGN, SIZE, DURATION

This is a cross-sectional study aimed to elucidate the molecular mechanisms underlying the impact of OEM on follicular development. Initially, miRNA expression profiles in follicular fluid (FF) samples were sequenced from patients with infertility related to OEM (N = 3) and male factor (MF) infertility (N = 3), with the latter serving as the control group. Differentially expressed miRNAs were validated in additional samples from each group (N = 55 in OEM group and N = 45 in MF group) to confirm candidate miRNAs. The study also investigated indicators associated with GCs dysfunction in vitro on rat GCs. Subsequently, rat models of OEM were established through endometrial allogeneic transplantation, and fertility experiments were conducted to assess the let-7/IGF1R axis response to OEM in vivo. Patient samples were collected between May 2018 and April 2019, and the mechanistic study was conducted over the subsequent three years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

FF and GC samples were obtained from infertile patients undergoing IVF treatment for OEM and MF related infertility. miRNA expression profiles in FF samples were analyzed using second-generation high-throughput sequencing technology, and candidate miRNAs were validated through quantitative PCR (qPCR). In the in vitro experiments conducted with rat GCs, cell proliferation was assessed using the CCK-8 assay, while steroid hormone concentrations were measured using chemiluminescence. ATP content was determined with an ATP assay kit, and levels of ROS were quantified using flow cytometry. A dual luciferase reporter gene assay was employed to identify the target gene of let-7 based on the construction of a IGF1R reporter gene plasmid using 293T cells. Western blotting was utilized to evaluate the expression of IGF1R in GCs, as well as its downstream proteins, and changes in signaling pathways following let-7 agomir/antagomir transfection and/or Igf1r silencing. In the in vivo OEM rat models, alterations in ovarian structure and cyst morphology were observed using hematoxylin and eosin staining. The expressions of let-7 and Igf1r in GCs were evaluated through qPCR, while variations in IGF1R expression were investigated with immunohistochemistry.

MAIN RESULTS AND THE ROLE OF CHANCE

The cohort of patients with ovarian OEM in this study exhibited significantly decreased antral follicle counts, oocyte retrieval numbers, and normal fertilization rates compared to the control group with MF. The expression of the let-7 miRNA family was markedly upregulated in the FF and GCs of OEM patients. Transfection of rat GCs with let-7 agonists diminished the functions of GCs, including disrupted cell proliferation, mitochondrial oxidative phosphorylation, and steroid hormone secretion, while transfection of rat GCs with let-7 antagonists caused the opposite effects. Luciferase reporter gene experiments confirmed that let-7 complementarily bound to the 3'-untranslated regions of IGF1R. Stimulation of let-7 expression in rat GCs led to a significant decrease in IGF1R expression, while inhibition of let-7 increased IGF1R expression. The expression of IGF1R in the GCs of OEM patients was also significantly reduced compared to MF patients. Silencing of Igf1r led to the dysfunction of GCs, similar to the effects of let-7 agonization, as demonstrated by the downregulation of key proteins involved in cell proliferation (CCND2 and CCND3) and oestradiol synthesis, as well as an increase in progesterone synthesis (StAR), while implicating the PI3K-Akt and MAPK signaling pathways. The antagonistic effect of let-7 on GCs was ineffective when Igf1r was silenced. Conversely, the agonistic effect of let-7 on GCs could be reversed by stimulation with the IGF1R ligand IGF-1. These findings suggested that let-7 regulated the proliferation, differentiation, and ATP synthesis of GCs through targeting IGF1R. The OEM rat model demonstrated alterations in ovarian morphology and structure, along with reduced fertility. Let-7 expression was significantly upregulated in GCs of OEM rats compared to normal rats, while Igf1r and IGF1R expression in pre-ovulatory follicular GCs were notably downregulated, supporting the notion that elevated let-7 expression in the follicular microenvironment of OEM inhibited IGF1R, leading to abnormal GC function and impacting fertility at the molecular level.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The synthesis and secretion mechanisms of steroid hormones are intricate and complex. Some enzymes that regulate oestrogen synthesis also play a role in progesterone synthesis. Moreover, certain receptors can respond to multiple hormone signals. Therefore, in this study, the expression patterns of key enzymes such as CYP17A, CYP11A1, HSD3B2, StAR, and receptors including AR, LHCGR, FSHR, ESR2, might be influenced by various factors and might not demonstrate complete consistency.

WIDER IMPLICATIONS OF THE FINDINGS

Future research will concentrate on investigating the potential impact of ovarian stromal cells on the external microenvironment of follicle growth. Additionally, screening for small molecule drugs that target let-7 and IGF1R actions can be conducted to intervene and modify the ovarian microenvironment, ultimately enhancing ovarian function.

STUDY FUNDING/COMPETING INTEREST(S)

This study received funding from the National Natural Science Foundation of China (grant number 82301851 to L.B.S., grant numbers U23A20403 and U20A20349 to S.Y.Z., and grant number 82371637 to Y.D.D.) and the Natural Science Foundation of Zhejiang Province (grant LTGY23H040010 to F.Z.). The authors have no conflicts of interest to declare.

Role of Non-coding RNAs on the Radiotherapy Sensitivity and Resistance in Cancer Cells

Radiotherapy (RT) is an integral part of treatment management in cancer patients. However, one of the limitations of this treatment method is the resistance of cancer cells to radiotherapy. These restrictions necessitate the introduction of modalities for the radiosensitization of cancer cells. It has been shown that Noncoding RNAs (ncRNAs), along with modifiers, can act as radiosensitivity and radioresistant regulators in a variety of cancers by affecting double strand break (DSB), wnt signaling, glycolysis, irradiation induced apoptosis, ferroptosis and cell autophagy. This review will provide an overview of the latest research on the roles and regulatory mechanisms of ncRNA after RT in in vitro and preclinical researches.

Circ_0006174 Upregulates IGF1R to Enhance Radioresistance and Tumorigenesis in Colorectal Cancer via miR-940 Suppression

Colorectal cancer (CRC) is one of the most common malignancies all over the world. Increasing evidence has revealed that circular RNAs (circRNAs) are involved in the progression of CRC. In this study, we aimed to investigate the role and underlying mechanism of circ_0006174 in the development and radiosensitivity of CRC. Circ_0006174, microRNA-940 (miR-940), and insulin-like growth factor 1 receptor (IGF1R) expression levels were evaluated by real-time quantitative polymerase chain reaction (RT-qPCR). The radiosensitivity of cells also was assessed using colony formation assay. Besides, cell proliferation, apoptosis, migration, and invasion were detected by cell counting kit-8 (CCK-8), flow cytometry, and transwell assays. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were performed to verify the relationship between miR-940 and circ_0006174 or IGF1R. IGF1R protein level was examined using western blot. A xenograft tumor model was used to verify the function of circ_0006174 in CRC tumor growth in vivo. Circ_0006174 and IGF1R levels were elevated and miR-940 expression was decreased in CRC tissues and cells. Circ_0006174 knockdown enhanced the radiosensitivity of CRC cells by regulating cell proliferation, apoptosis, migration, and invasion in vitro. In mechanism, circ_0006174 served as a sponge for miR-940 to upregulate IGF1R expression. Moreover, circ_0006174 silencing suppressed CRC growth in vivo. Circ_0006174 boosts radioresistance of CRC cells at least partly through upregulating IGF1R expression by sponging miR-940, providing a novel theoretical basis for CRC therapy.

Let-7 reduces the proliferation and migration of oral cancer cells via PI3K/AKT signaling pathway

The involvement of let-7 in the occurrence and progression of various cancers has been well-documented. However, the precise molecular mechanisms underlying its impact on oral cancer development remain unclear. In this study, we aimed to elucidate the role of let-7 in oral cancer progression and investigate its underlying molecular mechanisms. The expression of let-7 and high mobility group A2 (HMGA2) mRNA was assessed using the quantitative reverse transcription polymerase chain reaction. Western blot analysis was employed to detect the expression of key proteins in the PI3K/AKT signaling pathway as well as HMGA2 protein levels. The targeting relationship between let-7 and HMGA2 was predicted through bioinformatics methods and confirmed via luciferase reporter gene assay. The effects of let-7 and HMGA2 on the functionality of oral cancer cells were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, colony formation assay, Transwell assay, wound healing assay, and Annexin V/PI apoptosis assay. Additionally, the impact of let-7 on the growth of oral cancer cells in vivo was investigated by inducing subcutaneous tumor formation in nude mice. Let-7 effectively suppresses the proliferation, migration, and invasion of oral cancer cells by inhibiting the activation of the PI3K/AKT signaling pathway. HMGA2, a downstream target gene of let-7, exhibits high expression in oral cancer. However, overexpression of HMGA2 diminishes the inhibitory effects induced by let-7 overexpression on the proliferation, migration, and invasion of oral cancer cells. The occurrence and progression of oral cancer cells are inhibited by Let-7 through the downregulation of HMGA2, potentially mediated by the inhibition of PI3K/AKT signaling pathway activation.

Molecular functions of microRNAs in colorectal cancer: recent roles in proliferation, angiogenesis, apoptosis, and chemoresistance

MiRNAs (microRNAs) constitute a group of diminutive molecules of non-coding RNA intricately involved in regulating gene expression. This regulation is primarily accomplished through the binding of miRNAs to complementary sequences situated in the 3'-UTR of the messenger RNA (mRNA) target; as a result, they are degraded or repressed. The multifaceted biogenesis of miRNAs is characterized by a meticulously orchestrated sequence of events encompassing transcription, processing, transportation, and decay. Colorectal cancer stands as a pervasive and formidable ailment, afflicting millions across the globe. Colorectal cancer is not well diagnosed early, and metastasis rates are high, which results in low survival rates in advanced stages. The genesis and progression of colorectal cancer are subject to the influence of genetic and epigenetic factors, among which miRNAs play a pivotal role. When it comes to colorectal cancer, miRNAs have a dual character, depending on the genes they target, functioning as either tumor suppressors or oncogenes and the prevailing cellular milieu. Their impact extends to modulating critical facets of colorectal cancer pathogenesis, including proliferation, angiogenesis, apoptosis, chemoresistance, and radiotherapy response. The discernible potential of miRNAs which are used as biomarkers to diagnose colorectal cancer, prognosis, and treatment response has come to the forefront. Notably, miRNAs are easily found and detected readily in a variety of biological fluids, including saliva, blood, urine, and feces. This prominence is attributed to the inherent advantages of miRNAs over conventional biomarkers, including heightened stability, specificity, sensitivity, and accessibility. Various investigations have pinpointed miRNA signatures or panels capable of differentiating colorectal cancer patients from their healthy counterparts, predicting colorectal cancer stage and survival, and monitoring colorectal cancer recurrence and therapy response. Although there has been research on miRNAs in various diseases, there has been less research on miRNAs in cancer. Moreover, updated results of preclinical and clinical studies on miRNA biomarkers and drugs are required. Nevertheless, the integration of miRNAs as biomarkers for colorectal cancer is not devoid of challenges and limitations. These encompass the heterogeneity prevalent among colorectal cancer subtypes and stages, the variability in miRNA expression across different tissues and individuals, the absence of standardized methodologies for miRNA detection and quantification, and the imperative for validation through extensive clinical trials. Consequently, further research is imperative to conclusively establish the clinical utility and reliability of miRNAs as colorectal cancer biomarkers. MiR-21 demonstrates carcinogenic characteristics by targeting several tumor suppressor genes, which encourages cell division, invasion, and metastasis. On the other hand, by controlling the Wnt/β-catenin pathway, the tumor suppressor miRNA miR-34a prevents CRC cell proliferation, migration, and invasion. Furthermore, in colorectal cancer, the miR-200 family increases chemotherapy sensitivity while suppressing epithelial-mesenchymal transition (EMT). As an oncogene, the miR-17-92 cluster targets elements of the TGF-β signaling pathway to encourage the growth of CRC cells. Finally, miR-143/145, which is downregulated in CRC, influences apoptosis and the progression of the cell cycle. These miRNAs affect pathways like Wnt, TGF-β, PI3K-AKT, MAPK, and EMT, making them potential clinical biomarkers and therapeutic targets. This review summarizes recent research related to miRNAs, their role in tumor progression and metastasis, and their potential as biomarkers and therapeutic targets in colorectal cancer. In addition, we combined miRNAs' roles in tumorigenesis and development with the therapy of CRC patients, leading to novel perspectives on colorectal cancer diagnosis and treatment.

Detailed role of Let-7e in human diseases

As part of the epigenetic machinery, microRNAs (miRNAs) are extensively utilized by eukaryotes. By modulating gene expression in a variety of ways, these short RNAs mediate crucial physiological processes. This suggests that abnormalities in miRNA biogenesis and expression can be traced back to a variety of diseases. In addition, miRNAs are promising clinical candidates, especially for preclinical diagnosis. The Let family of miRNAs was one of the first to be discovered. As a prominent member of this category, extensive research has been conducted on Let-7e. The vast majority of evidence indicates an association between let-7e dysregulation and the onset and progression of disease, including malignancies. Because their effect depends on the genetic profile of disease and the affected tissue, different miRNAs play diverse roles in various diseases. However, what counts in miRNA studies is that just one miRNA may target numerous mRNAs in a cell at the exact time, therefore summarizing the effect of a single miRNA in human diseases can provide better insights into disease detection and treatment. The goal of this study is to gain a deeper understanding of how let-7e functions in human cells so that it can be utilized more effectively in clinical settings for diagnosis, prognosis, and treatment. We have reviewed the research on let-7e, focusing on the molecular underpinnings of biological processes controlled by this miRNA that contribute to the development and etiology of numerous disorders.

The Simultaneous Effects of miR-145-5p and hsa-let-7a-3p on Colorectal Tumorigenesis: In Vitro Evidence

Purpose

MicroRNAs (miRNAs) are a group of small regulatory non-coding RNAs, which are dysregulated through tumor progression. let-7 and MIR-145 are both tumor suppressor microRNAs that are downregulated in a wide array of cancers including colorectal cancer (CRC).

Methods

This study was aimed to investigate the effect of simultaneous replacement of these two tumor suppressor miRNAs on proliferation, apoptosis, and migration of CRC cells. HCT-116 with lower expression levels of hsa-let-7a-3p and MIR-145-5p was selected for functional investigations. The cells were cultured and transfected with hsa-let-7a and MIR-145, separately and in combination. Cell viability and apoptosis rates were assessed by MTT assay and flow cytometry, respectively. Cell cycle status was further evaluated using flow cytometry and qRT-PCR was employed to evaluate gene expression.

Results

The obtained results showed that exogenous overexpression of MIR-145 and hsa-let-7a in HCT-116 cells could cooperatively decrease CRC cell proliferation and induce sub-G1 cell cycle arrest. Moreover, hsa-let-7a and MIR-145 co-transfection significantly increased apoptosis induction compared to separate transfected cells and control through modulating the expression levels of apoptosis-related genes including Bax, Bcl-2, P53, Caspase-3, Caspase-8, and Caspase-9. Furthermore, qRT-PCR results illustrated that hsa-let-7a and MIR-145 combination more effectively downregulated MMP-9 and MMP-2 expression, as the important modulators of metastasis, compared to the controls.

Conclusion

Taken together, considering that exogenous overexpression of MIR-145 and hsa-let-7a showed cooperative anti-cancer effects on CRC cells, their combination may be considered as a novel therapeutic strategy for the treatment of CRC.

A glimpse into let-7e roles in human disorders; friend or foe?

MicroRNAs (miRNAs) have been linked to abnormal expression and regulation in a number of diseases, including cancer. Recent studies have concentrated on miRNA Let-7e's significance in precision medicine for cancer screening and diagnosis as well as its prognostic and therapeutic potential. Differential let-7e levels in bodily fluids have the possibility to enable early detection of cancer utilizing less-invasive techniques, reducing biopsy-related risks. Although Let-7e miRNAs have been described as tumor suppressors, it is crucial to note that there exists proof to support their oncogenic activity in vitro and in in vivo. Let-7e's significance in chemo- and radiation treatment decisions has also been demonstrated. Let-7e can also prevent the synthesis of proinflammatory cytokines in a number of degenerative disorders, including musculoskeletal and neurological conditions. For the first time, an overview of the significance of let-7e in the prevention, detection, and therapy of cancer and other conditions has been given in the current review. Additionally, we focused on the specific molecular processes that underlie the actions of let-7e, more particularly, on malignant cells.

Small Extracellular Vesicles from adipose-derived stem cells suppress cell proliferation by delivering the let-7 family of microRNAs in ovarian cancer

INTRODUCTION

Ovarian cancer is the leading cause of death among women with gynecological cancer, and novel treatment options are urgently needed. Extracellular vesicles (EVs), including exosomes, may be one of the most promising therapeutic tools for various diseases. In this study, we aimed to investigate the therapeutic effects of adipose-derived stem cell-derived EVs (ADSC-EVs) on ovarian cancer cell lines.

MATERIALS AND METHODS

ADSCs and the ovarian cancer cell lines SKOV3 and OV90 were used for analysis. ADSC-EVs were isolated through ultracentrifugation and validated using a cryotransmission electron microscope, nanoparticle tracking analysis, and western blotting. Then, the effect of ADSC-EVs on ovarian cancer cells was investigated using IncuCyte and microRNA sequencing. Moreover, the potential functions of miRNAs were evaluated by gain-of function analysis and in silico analysis.

RESULTS

ADSC-EVs suppressed SKOV3 and OV90 cell proliferation. In particular, small EVs (sEVs) from ADSCs exhibited a stronger antitumor effect than ADSC-medium/large EVs (m/lEVs). Comparison of the miRNA profiles between ADSC-sEVs and ADSC-m/lEVs, along with downstream pathway analysis, suggested the involvement of the let-7 family. Overexpression of hsa-let-7b-5p and hsa-let-7e-5p significantly suppressed the proliferation of SKOV3 cells. In silico analysis revealed that four potential target genes of hsa-let-7b-5p and hsa-let-7e-5p were significantly associated with the prognoses of the patients.

CONCLUSION

ADSC-sEVs had a stronger antitumor effect than ADSC-m/lEVs. Hsa-let-7b-5p and hsa-let-7e-5p, which are highly abundant in ADSC-sEVs, suppressed cell proliferation. These findings may open up new possibilities for therapeutic approaches using ADSC-sEVs.

Review of possible mechanisms of radiotherapy resistance in cervical cancer

Radiotherapy is one of the main treatments for cervical cancer. Early cervical cancer is usually considered postoperative radiotherapy alone. Radiotherapy combined with cisplatin is the standard treatment for locally advanced cervical cancer (LACC), but sometimes the disease will relapse within a short time after the end of treatment. Tumor recurrence is usually related to the inherent radiation resistance of the tumor, mainly involving cell proliferation, apoptosis, DNA repair, tumor microenvironment, tumor metabolism, and stem cells. In the past few decades, the mechanism of radiotherapy resistance of cervical cancer has been extensively studied, but due to its complex process, the specific mechanism of radiotherapy resistance of cervical cancer is still not fully understood. In this review, we discuss the current status of radiotherapy resistance in cervical cancer and the possible mechanisms of radiotherapy resistance, and provide favorable therapeutic targets for improving radiotherapy sensitivity. In conclusion, this article describes the importance of understanding the pathway and target of radioresistance for cervical cancer to promote the development of effective radiotherapy sensitizers.

Non-coding RNAs in radiotherapy resistance: Roles and therapeutic implications in gastrointestinal cancer

Radiotherapy has become an indispensable and conventional means for patients with advanced solid tumors including gastrointestinal cancer. However, innate or acquired radiotherapy resistance remains a significant challenge and greatly limits the therapeutic effect, which results in cancer relapse and poor prognosis. Therefore, it is an urgent need to identify novel biomarkers and therapeutic targets for clarify the biological characteristics and mechanism of radiotherapy resistance. Recently, lots of studies have revealed that non-coding RNAs (ncRNAs) are the potential indicators and regulators of radiotherapy resistance via the mediation of various targets/pathways in different cancers. These findings may serve as a potential therapeutic strategy to overcome radiotherapy resistance. In this review, we will shed light on the recent findings regarding the functions and regulatory mechanisms of ncRNAs following radiotherapy, and comprehensively discuss their potential as biomarkers and therapeutic targets in radiotherapy resistance of gastrointestinal cancer.

The miR-34a-5p-c-MYC-CHK1/CHK2 Axis Counteracts Cancer Stem Cell-Like Properties and Enhances Radiosensitivity in Hepatocellular Cancer Through Repression of the DNA Damage Response

Radiotherapy has become an increasingly widespread modality for treating hepatocellular cancer (HCC); however, the development of radioresistance significantly limits its effectiveness and invariably leads to tumor recurrence. Cancer stem cell (CSC) theory offers a potential explanation for tumor relapse and radioresistance, but the underlying mechanism remains unknown. Herein we investigate the role of miRNA in molecular regulation of stemness and radioresistance in HCC. Two HCC radiation-resistant cell lines (Huh7-RR and SMMC-7721-RR) were established by selecting the radioresistant subpopulation from HCC cells via clonogenic survival assays. MiRNA Sequencing was used to identify potential radiosensitivity involved miRNA in HCC-RR cells. Xenograft tumor mouse model was established for in vivo study. CSC properties were assessed using sphere formation assay and side population (SP) cells analysis. We found that miR-34a-5p was significantly downregulated in HCC-RR cells. Overexpression of miR-34a-5p counteracts CSC properties and enhances radiosensitivity in HCC. Mechanistic investigation revealed that c-MYC is the direct target of miR-34a-5p. Overexpression of miR-34a-5p reversed c-MYC-induced radioresistance. Moreover, we found that the specific molecular mechanism was that c-MYC activated CHK1 and CHK2, which are two key DNA damage checkpoint kinases, and facilitated the DNA damage response to radiation. Repression of the miR-34a-5p-cMYC-CHK1/CHK2 axis contributes to the acquisition of radioresistance in HCC cells. In summary, the miR-34a-5p-c-MYC-CHK1/CHK2 axis counteracts cancer stem cell-like properties and enhances radiosensitivity in hepatocellular cancer through repression of the DNA damage response.

Mechanisms of microRNA action in rectal cancer radiotherapy

ABSTRACT

Preoperative neoadjuvant chemoradiotherapy, combined with total mesorectal excision, has become the standard treatment for advanced localized rectal cancer (RC). However, the biological complexity and heterogeneity of tumors may contribute to cancer recurrence and metastasis in patients with radiotherapy-resistant RC. The identification of factors leading to radioresistance and markers of radiosensitivity is critical to identify responsive patients and improve radiotherapy outcomes. MicroRNAs (miRNAs) are small, endogenous, and noncoding RNAs that affect various cellular and molecular targets. miRNAs have been shown to play important roles in multiple biological processes associated with RC. In this review, we summarized the signaling pathways of miRNAs, including apoptosis, autophagy, the cell cycle, DNA damage repair, proliferation, and metastasis during radiotherapy in patients with RC. Also, we evaluated the potential role of miRNAs as radiotherapeutic biomarkers for RC.

The clinicopathological and prognostic significances of IGF-1R and Livin expression in patients with colorectal cancer

Background

Colorectal cancer (CRC) is the third most common cancer worldwide. However, limited effective biomarkers are associated with the tumorigenesis and prognosis of CRC.

Methods

The present study identified potential signatures from The Cancer Genome Atlas (TCGA) database and further validated the identified biomarkers in CRC tissues by immunohistochemistry (IHC).

Results

The expression of insulin-like growth factor 1 receptor (IGF-1R) and Livin gene was significantly upregulated in CRC samples compared to the adjacent normal samples in the TCGA dataset. IHC indicated that IGF-1R and Livin protein levels are increased in CRC and adenoma tissues compared to normal tissues. Notably, the IGF-1R protein levels differed significantly between adenoma and CRC. The elevated IGF-1R and Livin expression was associated with CRC clinicopathological features, including age, gender, histological subtype, individual cancer stages, nodal metastasis, and TP53-mutant in TCGA. Additionally, the IGF-1R promoter methylation level was closely related to CRC. Consistent with the TCGA study, IHC indicated that overexpressed IGF-1R and Livin proteins were independent risk factors for stage and metastasis. A marked correlation was established between IGF-1R and Livin expression in CRC, while the survival map showed no significant correlation with CRC. Kaplan–Meier survival curves showed that CRC patients with high IGF-1R or Livin expression had a prolonged overall disease-free survival than those with low expression in TCGA.

Conclusion

IGF-1R and Livin are associated with CRC tumorigenesis and might be valuable for novel biomarker identification and targeted therapeutic strategy development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09961-y.

Role of non-coding RNAs in radiosensitivity of colorectal cancer: A narrative review

Colorectal cancer (CRC) is a global public health concern because of its high prevalence and mortality. Although radiotherapy is a key method for treating CRC, radioresistance is an obstacle to radiotherapy use. The molecular mechanisms underlying the radioresistance of CRC remain unclear. Increasing evidence has revealed the multiple regulatory functions of non-coding RNAs (ncRNAs) in numerous malignancies, including CRC. Several ncRNAs have been reported to be involved in the determination of radiosensitivity of CRC cells, and some have excellent potential to be prognostic biomarkers or therapeutic targets in CRC treatment. The present review discusses the biological functions and underlying mechanisms of ncRNAs (primarily lncRNA, miRNA, and circRNA) in the regulation of the radiosensitivity of CRC. We also evaluate studies that examined ncRNAs as biomarkers of response to radiation and as therapeutic targets for enhancing radiosensitivity.

miRNAs as cornerstones in colorectal cancer pathogenesis and resistance to therapy: A spotlight on signaling pathways interplay - A review

Colorectal cancer (CRC) is the world's third most prevalent cancer and the main cause of cancer-related mortality. A lot of work has been put into improving CRC patients' clinical care, including the development of more effective methods and wide biomarkers variety for prognostic, and diagnostic purposes. MicroRNAs (miRNAs) regulate a variety of cellular processes and play a significant role in the CRC progression and spread via controlling their target gene expression by translation inhibition or mRNA degradation. Consequently, dysregulation and disruption in their function, miRNAs are linked to CRC malignant pathogenesis by controlling several cellular processes involved in the CRC. These cellular processes include increased proliferative and invasive capacity, cell cycle aberration, evasion of apoptosis, enhanced EMT, promotion of angiogenesis and metastasis, and decreased sensitivity to major treatments. The miRNAs control cellular processes in CRC via regulation of pathways such as Wnt/β-catenin signaling, PTEN/AKT/mTOR axis, KRAS, TGFb signaling, VEGFR, EGFR, and P53. Hence, the goal of this review was to review miRNA biogenesis and present an updated summary of oncogenic and tumor suppressor (TS) miRNAs and their potential implication in CRC pathogenesis and responses to chemotherapy and radiotherapy. We also summarise the biological importance and clinical applications of miRNAs in the CRC.

The Role of LncRNAs in the Regulation of Radiotherapy Sensitivity in Cervical Cancer

Cervical cancer (CC) is one of the three majors gynecological malignancies, which seriously threatens women’s health and life. Radiotherapy (RT) is one of the most common treatments for cervical cancer, which can reduce local recurrence and prolong survival in patients with cervical cancer. However, the resistance of cancer cells to Radiotherapy are the main cause of treatment failure in patients with cervical cancer. Long non-coding RNAs (LncRNAs) are a group of non-protein-coding RNAs with a length of more than 200 nucleotides, which play an important role in regulating the biological behavior of cervical cancer. Recent studies have shown that LncRNAs play a key role in regulating the sensitivity of radiotherapy for cervical cancer. In this review, we summarize the structure and function of LncRNAs and the molecular mechanism of radiosensitivity in cervical cancer, list the LncRNAs associated with radiosensitivity in cervical cancer, analyze their potential mechanisms, and discuss the potential clinical application of these LncRNAs in regulating radiosensitivity in cervical cancer.

The Advances in Epigenetics for Cancer Radiotherapy

Cancer is an important factor threatening human life and health; in recent years, its morbidity and mortality remain high and demosntrate an upward trend. It is of great significance to study its pathogenesis and targeted therapy. As the complex mechanisms of epigenetic modification has been increasingly discovered, they are more closely related to the occurrence and development of cancer. As a reversible response, epigenetic modification is of great significance for the improvement of classical therapeutic measures and the discovery of new therapeutic targets. It has become a research focusto explore the multi-level mechanisms of RNA, DNA, chromatin and proteins. As an important means of cancer treatment, radiotherapy has made great progress in technology, methods, means and targeted sensitization after years of rapid development, and even research on radiotherapy based on epigenetic modification is rampant. A series of epigenetic effects of radiation on DNA methylation, histone modification, chromosome remodeling, RNA modification and non-coding RNA during radiotherapy affects the therapeutic effects and prognosis. Starting from the epigenetic mechanism of tumorigenesis, this paper reviews the latest progress in the mechanism of interaction between epigenetic modification and cancer radiotherapy and briefly introduces the main types, mechanisms and applications of epigenetic modifiers used for radiotherapy sensitization in order to explore a more individual and dynamic approach of cancer treatment based on epigenetic mechanism. This study strives to make a modest contribution to the progress of human disease research.

Analysis of miR-143, miR-1, miR-210 and let-7e Expression in Colorectal Cancer in Relation to Histopathological Features

Background: MicroRNAs (miRNAs) are small RNA molecules involved in the control of the expression of many genes and are responsible for, among other things, cell death, differentiation and the control of their division. Changes in miRNA expression profiles have been observed in colorectal cancer. This discovery significantly enriches our knowledge of the pathogenesis of colorectal cancer and offers new goals in diagnostics and therapy. Aim: The aim of this study was to analyze the expression of four miRNA sequences—miR-143, miR-1, miR-210 and let-7e—and to investigate their significance in the risk of developing colorectal cancer. Materials and methods: miRNA sequences were investigated in formalin-fixed, paraffin-embedded (FFPE) tissue in colorectal cancer patients (n = 150) and in cancer-free controls (n = 150). The real-time PCR method was used. Results: This study revealed a lower expression of miR-143 in colorectal cancer patients than in the controls. miR-143 was positively correlated with the degree of tumor differentiation (grading). Three out of four analyzed miRNA (miR-1, miR-210 and let-7e) were found to be statistically insignificant in terms of colorectal carcinoma risk. Conclusions: miR-143 may be associated with the development of colorectal cancer.

The Roles of Non-Coding RNAs in Radiotherapy of Gastrointestinal Carcinoma

Radiotherapy (RT), or radiation therapy, has been widely used in clinical practice for the treatment of local advanced gastrointestinal carcinoma. RT causes DNA double-strand breaks leading to cell cytotoxicity and indirectly damages tumor cells by activating downstream genes. Non-coding RNA (including microRNAs, long non-coding RNAs (ncRNAs), and circular RNAs) is a type of RNA that does not encode a protein. As the field of ncRNAs increasingly expands, new complex roles have gradually emerged for ncRNAs in RT. It has been shown that ncRNAs can act as radiosensitivity regulators in gastrointestinal carcinoma by affecting DNA damage repair, cell cycle arrest, irradiation-induced apoptosis, cell autophagy, stemness, EMT, and cell pyroptosis. Here, we review the complex roles of ncRNAs in RT and gastrointestinal carcinoma. We also discuss the potential clinical significance and predictive value of ncRNAs in response to RT for guiding the individualized treatment of patients. This review can serve as a guide for the application of ncRNAs as radiosensitivity enhancers, radioresistance inducers, and predictors of response in RT of gastrointestinal carcinoma.

Diabetes and Colorectal Cancer Risk: A New Look at Molecular Mechanisms and Potential Role of Novel Antidiabetic Agents

Epidemiological data have demonstrated a significant association between the presence of type 2 diabetes mellitus (T2DM) and the development of colorectal cancer (CRC). Chronic hyperglycemia, insulin resistance, oxidative stress, and inflammation, the processes inherent to T2DM, also play active roles in the onset and progression of CRC. Recently, small dense low-density lipoprotein (LDL) particles, a typical characteristic of diabetic dyslipidemia, emerged as another possible underlying link between T2DM and CRC. Growing evidence suggests that antidiabetic medications may have beneficial effects in CRC prevention. According to findings from a limited number of preclinical and clinical studies, glucagon-like peptide-1 receptor agonists (GLP-1RAs) could be a promising strategy in reducing the incidence of CRC in patients with diabetes. However, available findings are inconclusive, and further studies are required. In this review, novel evidence on molecular mechanisms linking T2DM with CRC development, progression, and survival will be discussed. In addition, the potential role of GLP-1RAs therapies in CRC prevention will also be evaluated.

Downregulation of let-7 by Electrical Acupuncture Increases Protein Synthesis in Mice

BACKGROUND

Our previous study found that acupuncture with low frequency electrical stimulation (Acu/LFES) prevents muscle atrophy by attenuation of protein degradation in mice. The current study examines the impact of Acu/LFES on protein synthesis.

METHOD

C57/BL6 mice received Acu/LFES treatment on hindlimb for 30 min once. Acu/LFES points were selected by WHO Standard Acupuncture Nomenclature and electric stimulation applied using an SDZ-II Electronic acupuncture instrument. Muscle protein synthesis was measured by the surface-sensing of translation (SUnSET) assay. Exosomes were isolated using serial centrifugation and concentration and size of the collected exosomes were measured using a NanoSight instrument. The mature microRNA library in serum exosomes was validated using a High Sensitivity DNA chip.

RESULTS

Protein synthesis was enhanced in the both hindlimb and forelimb muscles. Blocking exosome secretion with GW4869 decreased the Acu/LFES-induced increases in protein synthesis. MicroRNA-deep sequencing demonstrated that four members of the Let-7 miRNA family were significantly decreased in serum exosomes. Real time qPCR further verified Acu/LFES-mediated decreases of let-7c-5p in serum exosomes and skeletal muscles. In cultured C2C12 myotubes, inhibition of let-7c not only increased protein synthesis, but also enhanced protein abundance of Igf1 and Igf1 receptors. Using a luciferase reporter assay, we demonstrated that let-7 directly inhibits Igf1.

CONCLUSION

Acu/LFES on hindlimb decreases let-7-5p leading to upregulation of the Igf1 signaling and increasing protein synthesis in both hindlimb and forelimb skeletal muscles. This provides a new understanding of how the electrical acupuncture treatment can positively influence muscle health.

IGF1-mediated HOXA13 overexpression promotes colorectal cancer metastasis through upregulating ACLY and IGF1R

Metastasis is the major reason for the high mortality of colorectal cancer (CRC) patients and its molecular mechanism remains unclear. Here, we report a novel role of Homeobox A13 (HOXA13), a member of the Homeobox (HOX) family, in promoting CRC metastasis. The elevated expression of HOXA13 was positively correlated with distant metastasis, higher AJCC stage, and poor prognosis in two independent CRC cohorts. Overexpression of HOXA13 promoted CRC metastasis whereas downregulation of HOXA13 suppressed CRC metastasis. Mechanistically, HOXA13 facilitated CRC metastasis by transactivating ATP-citrate lyase (ACLY) and insulin-like growth factor 1 receptor (IGF1R). Knockdown of ACLY and IGFIR inhibited HOXA13-medicated CRC metastasis, whereas ectopic overexpression of ACLY and IGFIR rescued the decreased CRC metastasis induced by HOXA13 knockdown. Furthermore, Insulin-like growth factor 1 (IGF1), the ligand of IGF1R, upregulated HOXA13 expression through the PI3K/AKT/HIF1α pathway. Knockdown of HOXA13 decreased IGF1-mediated CRC metastasis. In addition, the combined treatment of ACLY inhibitor ETC-1002 and IGF1R inhibitor Linsitinib dramatically suppressed HOXA13-mediated CRC metastasis. In conclusion, HOXA13 is a prognostic biomarker in CRC patients. Targeting the IGF1-HOXA13-IGF1R positive feedback loop may provide a potential therapeutic strategy for the treatment of HOXA13-driven CRC metastasis.

DCLK1 Inhibition Sensitizes Colorectal Cancer Cells to Radiation Treatment

Colorectal cancer (CRC) is one of the most prevalent diagnosed cancers and a common cause of cancer-related mortality. Despite effective clinical responses, a large proportion of patients undergo resistance to radiation therapy. Therefore, the identification of efficient targeted therapy strategies would be beneficial to overcome cancer radioresistance. Doublecortin-like kinase 1 (DCLK1) is an intestinal and pancreatic stem cell marker that showed overexpression in a variety of cancers. The transfection of DCLK1 siRNA to ‎normal HCT-116 cells was performed, and then cells were irradiated with X-rays. The effects of DCLK1 inhibition on cell survival, apoptosis, cell cycle, DNA damage response (ATM and γH2AX proteins), epithelial-mesenchymal transition (EMT) related genes (vimentin, N-cadherin, and E-cadherin), cancer stem cells markers (CD44, CD133, ALDH1, and BMI1), and β-catenin signaling pathway (β-catenin) were evaluated. DCLK1 siRNA downregulated DCLK1 expression in HCT-116 cells at both mRNA and protein levels (P <0.01). Colony formation assay showed a significantly reduced cell survival in the DCLK1 siRNA transfected group in comparison with the control group following exposure to 4 and 6 Gy doses of irradiation (P <0.01). Moreover, the expression of cancer stem cells markers (P <0.01), EMT related genes (P <0.01), and DNA repair proteins including pATM (P <0.01) and γH2AX (P <0.001) were significantly decreased in the transfected cells in comparison with the nontransfected group after radiation. Finally, the cell apoptosis rate (P <0.01) and the number of cells in the G0/G1 phase in the silencing DCLK1 group was increased (P <0.01). These findings suggest that DCLK1 can be considered a promising therapeutic target for the treatment of radioresistant human CRC.

let-7e downregulation characterizes early phase colonic adenoma in APCMin/+ mice and human FAP subjects

The crypt-villus axis represents the essential unit of the small intestine, which integrity and functions are fundamental to assure tissue and whole-body homeostasis. Disruption of pathways regulating the fine balance between proliferation and differentiation results in diseases development. Nowadays, it is well established that microRNAs (miRNAs) play a crucial role in the homeostasis maintenance and perturbation of their levels may promote tumor development. Here, by using microarray technology, we analysed the miRNAs differentially expressed between the crypt and the villus in mice ileum. The emerged miRNAs were further validated by Real Time qPCR in mouse model (ApcMin/+), human cell lines and human tissue samples (FAP) of colorectal cancer (CRC). Our results indicated that miRNAs more expressed in the villi compartment are negatively regulated in tumor specimens, thus suggesting a close association between these microRNAs and the differentiation process. Particularly, from our analysis let-7e appeared to be a promising target for possible future therapies and a valuable marker for tumor staging, being upregulated in differentiated cells and downregulated in early-stage colonic adenoma samples.

MicroRNA: a novel implication for damage and protection against ionizing radiation

Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various cancers. It is significant to reduce radiation injury but maximize the effect of radiotherapy. MicroRNAs (miRNAs) are posttranscriptionally regulatory factors involved in cellular radioresponse. In this review, we show how miRNAs regulate important genes on cellular response to IR-induced damage and how miRNAs participate in IR-induced carcinogenesis. Additionally, we summarize the experimental and clinical evidence for miRNA involvement in radiotherapy and discuss their potential for improvement of radiotherapy. Finally, we highlight the role that miRNAs play in accident exposure to IR or radiotherapy as predictive biomarker. miRNA therapeutics have shown great perspective in radiobiology; miRNA may become a novel strategy for damage and protection against IR.

Relationship between Sphk1/S1P and microRNAs in human cancers

Sphingosine kinases type 1 (SphK1) is a key enzyme in the phosphorylation of sphingosine to sphingosine 1-phosphate (S1P). Different abnormalities in SphK1 functions may correspond with poor prognosis in various cancers. Additionally, upregulated SphK1/S1P could promote cancer cell proliferation, angiogenesis, mobility, invasion, and metastasis. MicroRNAs as conserved small noncoding RNAs play major roles in cancer initiation, progression, metastasis, etc. Their posttranscriptionally mechanisms could affect the development of cancer growth or tumorigenesis suppression. The growing number of studies has described that various microRNAs can be regulated by SphK1, and its expression level can also be regulated by microRNAs. In this review, the relationship of SphK1 and microRNA functions and their interaction in human malignancies have been discussed. Based on them novel treatment strategies can be introduced.

Exosomal circ_IFT80 Enhances Tumorigenesis and Suppresses Radiosensitivity in Colorectal Cancer by Regulating miR-296-5p/MSI1 Axis

Background

Exosomal circular RNAs (circRNAs) can act as biomarkers and play crucial roles in colorectal cancer (CRC) and radiosensitivity. The aim of this study was to explore the functions and regulatory mechanism of exosomal circRNA intraflagellar transport 80 (circ_IFT80) in tumorigenesis and radiosensitivity of CRC.

Methods

Exosomes were detected using transmission electron microscopy (TEM). Protein levels were determined by Western blot assay. The expression of circ_IFT80, microRNA-296-5p (miR-296-5p) and musashi1 (MSI1) was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell cycle distribution, cell apoptosis, and cell proliferation were detected by flow cytometry and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, respectively. Colony formation assay was used to determine the radiosensitivity of cells. The interaction between miR-296-5p and circ_IFT80 or MSI1 was verified by dual-luciferase reporter assay. A xenograft tumor model was established to explore the role of exosomal circ_IFT80 in vivo.

Results

Circ_IFT80 was upregulated in exosomes derived from CRC patient serum and CRC cells. Exosomal circ_IFT80 or circ_IFT80 overexpression facilitated tumorigenesis by increasing cell proliferation and reducing apoptosis, and inhibited radiosensitivity via promoting colony formation and inhibiting apoptosis. Additionally, circ_IFT80 acted as a sponge of miR-296-5p, and miR-296-5p reversed the effects of circ_IFT80 on tumorigenesis and radiosensitivity. Moreover, MSI1 was a direct target of miR-296-5p. Furthermore, miR-296-5p overexpression inhibited tumorigenesis and promoted radiosensitivity by downregulating MSI1. Exosomal circ_IFT80 also accelerated tumor growth in vivo.

Conclusion

Exosomal circ_IFT80 promoted tumorigenesis and reduced radiosensitivity by regulating miR-296-5p/MSI1 axis, which might provide a novel avenue for treatment of CRC.

GH and IGF System: The Regulatory Role of miRNAs and lncRNAs in Cancer

Growth hormone (GH) and the insulin-like growth factor (IGF) system are involved in many biological processes and have growth-promoting actions regulating cell proliferation, differentiation, apoptosis and angiogenesis. A recent chapter in epigenetics is represented by microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) which regulate gene expression. Dysregulated miRNAs and lncRNAs have been associated with several diseases including cancer. Herein we report the most recent findings concerning miRNAs and lncRNAs regulating GH and the IGF system in the context of pituitary adenomas, osteosarcoma and colorectal cancer, shedding light on new possible therapeutic targets. Pituitary adenomas are increasingly common intracranial tumors and somatotroph adenomas determine supra-physiological GH secretion and cause acromegaly. Osteosarcoma is the most frequent bone tumor in children and adolescents and was reported in adults who were treated with GH in childhood. Colorectal cancer is the third cancer in the world and has a higher prevalence in acromegalic patients.

The Emerging Role of miRNAs for the Radiation Treatment of Pancreatic Cancer

Simple Summary

Pancreatic cancer is an aggressive disease with a high mortality rate. Radiotherapy is one treatment option within a multimodal therapy approach for patients with locally advanced, non-resectable pancreatic tumors. However, radiotherapy is only effective in about one-third of the patients. Therefore, biomarkers that can predict the response to radiotherapy are of utmost importance. Recently, microRNAs, small non-coding RNAs regulating gene expression, have come into focus as there is growing evidence that microRNAs could serve as diagnostic, predictive and prognostic biomarkers in various cancer entities, including pancreatic cancer. Moreover, their high stability in body fluids such as serum and plasma render them attractive candidates for non-invasive biomarkers. This article describes the role of microRNAs as suitable blood biomarkers and outlines an overview of radiation-induced microRNAs changes and the association with radioresistance in pancreatic cancer.

Abstract

Today, pancreatic cancer is the seventh leading cause of cancer-related deaths worldwide with a five-year overall survival rate of less than 7%. Only 15–20% of patients are eligible for curative intent surgery at the time of diagnosis. Therefore, neoadjuvant treatment regimens have been introduced in order to downsize the tumor by chemotherapy and radiotherapy. To further increase the efficacy of radiotherapy, novel molecular biomarkers are urgently needed to define the subgroup of pancreatic cancer patients who would benefit most from radiotherapy. MicroRNAs (miRNAs) could have the potential to serve as novel predictive and prognostic biomarkers in patients with pancreatic cancer. In the present article, the role of miRNAs as blood biomarkers, which are associated with either radioresistance or radiation-induced changes of miRNAs in pancreatic cancer, is discussed. Furthermore, the manuscript provides own data of miRNAs identified in a pancreatic cancer mouse model as well as radiation-induced miRNA changes in the plasma of tumor-bearing mice.

miRNA as promising theragnostic biomarkers for predicting radioresistance in cancer: A systematic review and meta-analysis

Radioresistance remains as an obstacle in cancer treatment. This systematic review and meta-analysis aimed to evaluate the association between the expression of miRNAs and responses to radiotherapy and the prognosis of different tumors. In total, 77 miRNAs in 19 cancer types were studied, in which 24 miRNAs were upregulated and 58 miRNAs were downregulated in cancer patients. Five miRNAs were differentially expressed. Moreover, 75 miRNAs were found to be related to radioresistance, while 5 were observed to be related to radiosensitivity. The pooled HR and 95 % confidence interval for the combined studies was 1.135 (0.819-1.574; P-value = 0.4). The HR values of the subgroup analysis for miR-21 (HR = 2.344; 95 % CI: 1.927-2.850; P-value = 0.000), nasopharyngeal carcinoma (HR = 0.448; 95 % CI: 0.265-0.760; P = 0.003) and breast cancer (HR = 1.131; 95 % CI: 0.311-4.109; P = .85) were obtained. Our results highlighted that across the published literature, miRNAs can modulate tumor radioresistance or sensitivity by affecting radiation-related signaling pathways. It seems that miRNAs could be considered as a theragnostic biomarker to predict and monitor clinical response to radiotherapy. Thus, the prediction of radioresistance in malignant patients will improve radiotherapy outcomes and radiotherapeutic resistance.

Inhibition of semaphorin 4D enhances chemosensitivity by increasing 5-fluorouracile-induced apoptosis in colorectal cancer cells

Overexpression of semaphorin 4D (SEMA4D), an immune semaphorin, is found in various human malignancies, including colorectal cancer (CRC). In this study, we explored the relationship between silencing SEMA4D expression and 5-fluorouracil (5-FU) response in the colorectal cancer cell line. SW48 cells were transfected with a short interfering RNA (siRNA) in order to silence SEMA4D gene expression and then exposed to 5-FU for 48 h. The down-regulation of SEMA4D expression was confirmed by qRT-PCR and the particular concentration of 5-FU was acquired using MTT assay. Flow cytometry and western blot were used to evaluate apoptosis rate and pro- and anti-apoptotic expression levels of proteins involved in apoptosis including Bax, Bcl-2, P53, and caspase-3. Other oncogenic activities including epithelial-mesenchymal transition (EMT) process, cancer stem cell (CSC) markers, and β-catenin pathway were investigated using qRT-PCR, and western blot. The proliferation was analyzed via colony formation test and cell invasion was assessed by transwell assay. Our data demonstrate that SEMA4D silencing results in strikingly elevated apoptosis in response to 5-FU treatment and leads to down-regulation of Bcl-2 and overexpression of Bax, P53, and caspase-3 in protein levels. Furthermore, the mRNA and protein expression levels of β-catenin, as well as transcript expressions of CSCs and EMT markers, were remarkably diminished. However, mRNA expression of E-cadherin as an epithelial marker was significantly increased in 5-FU treatment combined with siRNA SEMA4D. This study implicates that the silencing of SEMA4D by siRNA promotes the chemosensitivity of SW48 cells to 5-FU and it may be a potential therapeutic agent for colon cancer therapy.

miRNA Clusters with Down-Regulated Expression in Human Colorectal Cancer and Their Regulation

Regulation of microRNA (miRNA) expression has been extensively studied with respect to colorectal cancer (CRC), since CRC is one of the leading causes of cancer mortality worldwide. Transcriptional control of miRNAs creating clusters can be, to some extent, estimated from cluster position on a chromosome. Levels of miRNAs are also controlled by miRNAs "sponging" by long non-coding RNAs (ncRNAs). Both types of miRNA regulation strongly influence their function. We focused on clusters of miRNAs found to be down-regulated in CRC, containing miR-1, let-7, miR-15, miR-16, miR-99, miR-100, miR-125, miR-133, miR-143, miR-145, miR-192, miR-194, miR-195, miR-206, miR-215, miR-302, miR-367 and miR-497 and analysed their genome position, regulation and functions. Only evidence provided with the use of CRC in vivo and/or in vitro models was taken into consideration. Comprehensive research revealed that down-regulated miRNA clusters in CRC are mostly located in a gene intron and, in a majority of cases, miRNA clusters possess cluster-specific transcriptional regulation. For all selected clusters, regulation mediated by long ncRNA was experimentally demonstrated in CRC, at least in one cluster member. Oncostatic functions were predominantly linked with the reviewed miRNAs, and their high expression was usually associated with better survival. These findings implicate the potential of down-regulated clusters in CRC to become promising multi-targets for therapeutic manipulation.

Investigating the effect of radiosensitizer for Ursolic Acid and Kamolonol Acetate ‌ on HCT-116 cell line

PURPOSE

The aim of this study was evaluating the cytotoxic and radiosensitizing effects of Ursolic Acid (UA) and Kamolonol Acetate (KA) on HCT116 cell line and finally investigating the functional role of NF-κB and CCND1 genes in the radiosensitizing activity of UA and KA.

MATERIALS AND METHOD

The cytotoxic effects of UA and KA by MTT assay was evaluated on HCT-116. Clonogenic assay was performed to investigate of radiosensitizing effects of UA and KA on HCT116. To assessment the expression levels of NF-κB and CCND1 genes, real-time PCR method was used.

RESULTS

The results of MTT assay revealed that UA and KA have cytotoxic effects on HCT116 cell line. According to clonogenic assay, survival fraction of treated cells with UA and KA has been decreased compared to the survival fraction of untreated cells. UA and KA lead to the decrease in the expression level of NF-κB. Synergistic effect of radiosensitizing agents with radiation was only approved for UA and 2 Gy of radiation.

CONCLUSION

Based on our study, UA and KA have cytotoxic effects on HCT116 cell line. Furthermore, UA may lead to radiosensitization of human colorectal tumor cells by NF-κB1 and CCND1signaling pathways.

Let-7e Suppresses DNA Damage Repair and Sensitizes Ovarian Cancer to Cisplatin through Targeting PARP1

Increased DNA damage repair is one of the mechanisms implicated in cisplatin resistance. Our previous study indicated that the deregulation of let-7e promoted cisplatin resistance and that let-7e could suppress DNA double-strand break repair in ovarian cancer. In this study, we further characterized the role of let-7e in DNA damage repair and cisplatin resistance in ovarian cancer, and investigated the underlying mechanisms. The alkaline and neutral comet assay indicated that let-7e impeded both DNA single- and double-strand break repairs through downregulating its target gene PARP1. In vitro and in vivo experiments provided evidence that the let-7e-PARP1-DNA repair axis was involved in the modulation of cisplatin sensitivity in ovarian cancer. Contrary to let-7e, PARP1 was overexpressed in cisplatin-resistant ovarian cancer tissues, and patients with high PARP1 expression exhibited poor progression-free survival (PFS) and overall survival (OS). Multivariate logistic and Cox regression analyses showed that let-7e and FIGO stage were independent prognostic factors for PFS and OS, whereas let-7e and PARP1 were able to independently predict chemotherapy response. Taken together, our results indicated that low expression of let-7e promoted DNA single- and double-strand break repairs and subsequently contributed to cisplatin resistance by relieving the suppression on PARP1 in ovarian cancer. IMPLICATIONS: Targeting the let-7e-PARP1-DNA repair axis might be an effective strategy for the treatment of chemoresistant ovarian cancer.

Induction of let-7e gene expression attenuates oncogenic phenotype in HCT-116 colorectal cancer cells through targeting of DCLK1 regulation

AIMS

MicroRNAs (miRNAs) are small noncoding RNAs that negatively control gene expression at the translational level. There are compelling evidences indicating that the expression of let-7e is downregulated in various cancers, however, the role of let-7e in colorectal cancer (CRC) and its mechanism has been remained unknown. Here, we investigated the potential role of let-7e in regulating CRC cells phenotypes.

MAIN METHODS

Let-7e and DCLK1 siRNA were transfected in HCT-116 cells. Colony formation assay, scratch test, Annexin V/PI flow cytometry, and sphere formation assay were performed to examine the cell proliferation, migration, apoptosis, and stemness, respectively. The expression of let-7e, epithelial-mesenchymal transition (EMT)-related genes, Doublecortin like kinase protein 1 (DCLK1), and cancer stem cells (CSCs) were assessed using RT-qPCR while the protein level of DCLK1 was determined by western blotting.

KEY FINDINGS

Overexpression of let-7e effectively inhibited cell proliferation, suppressed migration, reduced sphere formation, and precluded EMT process as well as stemness factors. Furthermore, let-7e suppressed DCLK1 expression. Additionally, we found that the expression of let-7e was negatively correlated with DCLK1 expression in CRC cells.

SIGNIFICANCE

Let-7e plays an important role as tumor suppressor miRNA in CRC probably through inhibition of DCLK1 expression.

miR-328-3p mediates the anti-tumor effect in osteosarcoma via directly targeting MMP-16

Background

Increasing reports demonstrated that dysregulated expression of microRNAs (miRNAs) leads to the progression of various tumors. Previous studies revealed that miR-328-3p exhibited dysregulated expression in various types of tumors. However, its function and underlying mechanism in osteosarcoma (OS) are still unexplored.

Methods

The expression of miR-328-3p in the tissues and OS cell lines was detected by qRT-PCR analysis. The effects of miR-328-3p in the proliferation were analyzed by MTT assay. The proliferation and apoptosis of OS cells were examined by colony formation assay and TUNEL staining respectively. The migration and tumor formation ability of OS cells were measured by wound healing assay and xenograft in vivo mice assay. Furthermore, the regulatory roles of miR-328-3p/MMP16 were determined by western blot and luciferase reporter assay.

Results

The expression of miR-328-3p was significantly decreased in OS tissues and cell lines. Furthermore, overexpression of miR-328-3p inhibited the cell proliferation and migration, but promoted the apoptosis of OS cells in vitro. Moreover, the analysis in vivo showed that miR-328-3p effectively suppressed the formation of tumors. According to the results of western blot analysis and luciferase reporter assay, we identified matrix metalloproteinase-16 (MMP-16) acted as a direct target of miR-328-3p. Moreover, the expression level of MMP-16, which participates in the occurrence and development of many cancers, was negatively correlated with the miR-328-3p expression in OS cells.

Conclusion

miR-328-3p inhibited the proliferation, migration but accelerated the apoptosis of OS by directly inhibiting MMP-16. And miR-328-3p/MMP-16 axis may be one of the mechanisms of OS development and a novel potential method for the treatment of OS in clinic.