Shrimp miR-S8 Suppresses the Stemness of Human Melanoma Stem-like Cells by Targeting the Transcription Factor YB-1

Antiviral Shrimp lncRNA06 Possesses Anti-Tumor Activity by Inducing Apoptosis of Human Gastric Cancer Stem Cells in a Cross-Species Manner

Virus infection causes the metabolic disorder of host cells, whereas the metabolic disorder of cells is one of the major causes of tumorigenesis, suggesting that antiviral molecules might possess anti-tumor activities by regulating cell metabolism. As the key regulators of gene expression, long non-coding RNAs (lncRNAs) play vital roles in the regulation of cell metabolism. However, the influence of antiviral lncRNAs on tumorigenesis has not been explored. To address this issue, the antiviral and anti-tumor capacities of shrimp lncRNAs were characterized in this study. The results revealed that shrimp lncRNA06, having antiviral activity in shrimp, could suppress the tumorigenesis of human gastric cancer stem cells (GCSCs) via triggering apoptosis of GCSCs in a cross-species manner. Shrimp lncRNA06 could sponge human miR-17-5p to suppress the stemness of GCSCs via the miR-17-5p-p21 axis. At the same time, shrimp lncRNA06 could bind to ATP synthase subunit beta (ATP5F1B) to enhance the stability of the ATP5F1B protein in GCSCs, thus suppressing the tumorigenesis of GCSCs. The in vivo data demonstrated that shrimp lncRNA06 promoted apoptosis and inhibited the stemness of GCSCs through interactions with ATP5F1B and miR-17-5p, leading to the suppression of the tumorigenesis of GCSCs. Therefore, our findings highlighted that antiviral lncRNAs possessed anti-tumor capacities and that antiviral lncRNAs could be the anti-tumor reservoir for the treatment of human cancers.

Aspongopus chinensis ach-miR-276a-3p induces breast cancer cell cycle arrest by targeting APPL2 to regulate the CDK2-Rb-E2F1 signaling pathway

Breast cancer, the most common cancer, presents a significant challenge to the health and longevity of women. Aspongopus chinensis Dallas is an insect with known anti-breast cancer properties. However, the anti-breast cancer effects and underlying mechanisms have not been elucidated. Exogenous microRNAs (miRNAs), which are derived from plants and animals, have been revealed to have notable capacities for controlling the proliferation of cancerous cells. To elucidate the inhibitory effects of miRNAs derived from A. chinensis and the regulatory mechanism involved in the growth of breast cancer cells, miRNA sequencing was initially employed to screen for miRNAs both in A. chinensis hemolymph and decoction and in mouse serum and tumor tissue after decoction gavage. Subsequently, the experiments were performed to assess the suppressive effect of ach-miR-276a-3p, the miRNA screened out from a previous study, on the proliferation of MDA-MB-231 and MDA-MB-468 breast cancer cell lines in vitro and in vivo. Finally, the regulatory mechanism of ach-miR-276a-3p in MDA-MB-231 and MDA-MB-468 breast cancer cells was elucidated. The results demonstrated that ach-miR-276a-3p notably inhibited breast cancer cell proliferation, migration, colony formation, and invasion and induced cell cycle arrest at the G0/G1 phase. Moreover, the ach-miR-276a-3p mimics significantly reduced the tumor volume and weight in xenograft tumor mice. Furthermore, ach-miR-276a-3p could induce cell cycle arrest by targeting APPL2 and regulating the CDK2-Rb-E2F1 signaling pathway. In summary, ach-miR-276a-3p, derived from A. chinensis, has anti-breast cancer activity by targeting APPL2 and regulating the CDK2-Rb-E2F1 signaling pathway and can serve as a promising candidate anticancer agent.

MicroRNA PC-3p-2869 Regulates Antler Growth and Inhibits Proliferation and Migration of Human Osteosarcoma and Chondrosarcoma Cells by Targeting CDK8, EEF1A1, and NTN1

MicroRNAs (miRNAs) play a crucial role in maintaining the balance between the rapid growth and suppression of tumorigenesis during antler regeneration. This study investigated the role of a novel miRNA, PC-3p-2869 (miR-PC-2869), in antler growth and its therapeutic potential in human osteosarcoma and chondrosarcoma. Stem-loop RT-qPCR showed that miR-PC-2869 was expressed extensively in diverse layers of antler tissues. Overexpression of miR-PC-2869 suppressed the proliferation and migration of antler cartilage cells. Similarly, heterologous expression of miR-PC-2869 reduced the proliferation, colony formation, and migration of osteosarcoma cell line MG63 and U2OS and chondrosarcoma cell line SW1353. Moreover, 18 functional target genes of miR-PC-2869 in humans were identified based on the screening of the reporter library. Among them, 15 target genes, including CDK8, EEF1A1, and NTN1, possess conserved miR-PC-2869-binding sites between humans and red deer (Cervus elaphus). In line with this, miR-PC-2869 overexpression decreased the expression levels of CDK8, EEF1A1, and NTN1 in MG63, SW1353, and antler cartilage cells. As expected, the knockdown of CDK8, EEF1A1, or NTN1 inhibited the proliferation and migration of MG63, SW1353, and antler cartilage cells, demonstrating similar suppressive effects as miR-PC-2869 overexpression. Furthermore, we observed that CDK8, EEF1A1, and NTN1 mediated the regulation of c-myc and cyclin D1 by miR-PC-2869 in MG63, SW1353, and antler cartilage cells. Overall, our work uncovered the cellular functions and underlying molecular mechanism of antler-derived miR-PC-2869, highlighting its potential as a therapeutic candidate for bone cancer.

Non-coding RNA-related antitumor mechanisms of marine-derived agents

In the last two decades, natural active substances have attracted great attention in developing new antitumor drugs, especially in the marine environment. A series of marine-derived compounds or derivatives with potential antitumor effects have been discovered and developed, but their mechanisms of action are not well understood. Emerging studies have found that several tumor-related signaling pathways and molecules are involved in the antitumor mechanisms of marine-derived agents, including noncoding RNAs (ncRNAs). In this review, we provide an update on the regulation of marine-derived agents associated with ncRNAs on tumor cell proliferation, apoptosis, cell cycle, invasion, migration, drug sensitivity and resistance. Herein, we also describe recent advances in marine food-derived ncRNAs as antitumor agents that modulate cross-species gene expression. A better understanding of the antitumor mechanisms of marine-derived agents mediated, regulated, or sourced by ncRNAs will provide new biomarkers or targets for potential antitumor drugs from preclinical discovery and development to clinical application.

Radiochemotherapy-induced DNA repair promotes the biogenesis of gastric cancer stem cells

Background

Clinically, metastasis and recurrence occurred after routine radiochemotherapy in dozens of cases of gastric cancer, mainly attributed to the role of cancer stem cells (CSCs). Actually, radiochemotherapy could induce DNA damages, leading to activation of DNA repair which might be associated with acquisition of stem cell phenotype. Hitherto, the contribution made by active DNA repair to stemness induction has not been extensively explored.

Methods

Cisplatin/doxorubicin treatment and X-ray exposure were conducted in gastric cancer cell lines and gastric cancer cells derived from solid tumors to model clinical therapy. Quantitative real-time PCR, Western blot, and tumorsphere/tumor formation assay were further used to characterize CSCs and assess activation of DNA repair. RNA-seq was performed to identify which DNA repair genes were crucial for CSC traits induction, followed by the investigation of underlying mechanism and functional significance via in vitro and in vivo experiments.

Results

Here, we report a mechanism through which gastric cancer cells in response to radiochemotherapy were reprogrammed into gastric cancer stem cell-like cells. In this mechanism, radiochemotherapy triggers DNA damage response accompanied by elevated levels of EID3, a typical DNA repair gene, which interacts with NAMPT to promote stemness via upregulating Wnt signaling pathway, manifested by enhanced tumorsphere/tumor formation in gastric cancer. In addition to involvement of EID3 in stemness acquisition, it also shows impacts on proliferation, cell cycle, apoptosis and therapy resistance to maintain the characteristics of CSC populations.

Conclusion

Our study indicates that gastric cancer cells can be endowed with stemness traits via EID3-NAMPT-Wnt/β-catenin axis in response to radiochemotherapy. Blocking this axis (i.e., targeting EID3) along with radiochemotherapy might represent a potential strategy to sensitize CSCs to radiochemotherapy and further reinforce the anti-tumor effects of conventional treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03165-8.

Copy number amplification and SP1-activated lncRNA MELTF-AS1 regulates tumorigenesis by driving phase separation of YBX1 to activate ANXA8 in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are reported to play key roles in tumorigenesis. However, the mechanisms underlying lncRNA-mediated regulation of RNA-binding protein phase separation in tumorigenesis have not been completely elucidated. In this study, an oncogenic lncRNA MELTF-AS1 was identified using systematic data analysis, screening, and verification. MELTF-AS1 was markedly upregulated in non-small cell lung cancer (NSCLC). High MELTF-AS1 levels were associated with advanced tumor-node-metastasis stage (TNM), high tumor size, and decreased survival time. Functionally, MELTF-AS1 regulated cell proliferation and metastasis in vitro and in vivo. RNA sequencing analysis revealed that MELTF-AS1 knockdown specifically modulated genes associated with cell proliferation, apoptosis, and migration. Mechanistically, at the genome level, copy number amplification promoted MELTF-AS1 expression. At the transcriptional level, the transcription factor SP1 directly activated MELTF-AS1 transcription by binding to its promoter. Furthermore, MELTF-AS1 could directly bind and drive the phase separation of YBX1, which was an RNA-binding protein and involved in tumorigenesis, thus activating ANXA8 transcription and promoting tumorigenesis of NSCLC. Aberrant activation of ANXA8 and promotion of tumorigenesis have been found in a variety of tumors. These novel findings demonstrated the critical role of MELTF-AS1-driven phase separation-mediated transcriptional regulation and provided a potential novel diagnostic and therapeutic target for NSCLC.

YB-1 as an Oncoprotein: Functions, Regulation, Post-Translational Modifications, and Targeted Therapy

Y box binding protein 1 (YB-1) is a protein with a highly conserved cold shock domain (CSD) that also belongs to the family of DNA- and RNA-binding proteins. YB-1 is present in both the nucleus and cytoplasm and plays versatile roles in gene transcription, RNA splicing, DNA damage repair, cell cycle progression, and immunity. Cumulative evidence suggests that YB-1 promotes the progression of multiple tumor types and serves as a potential tumor biomarker and therapeutic target. This review comprehensively summarizes the emerging functions, mechanisms, and regulation of YB-1 in cancers, and further discusses targeted strategies.

Suppression of RNA editing by miR-17 inhibits the stemness of melanoma stem cells

More and more evidence suggests that microRNA (miRNA) and RNA editing play key roles in the development and progression of tumor. However, the influence of miRNA-mediated RNA editing on tumor stem cells remains unclear. In this study, the results demonstrated that miR-17, which was downregulated in melanoma stem cells, acted as a tumor inhibitor by suppressing the stemness of melanoma stem cells and promoting cell differentiation. MiR-17 targeted ADAR2 (adenosine deaminase acting on RNA 2), a gene encoding an editing enzyme required for the maintenance of melanoma stem cell stemness. In melanoma stem cells, ADAR2 was responsible for DOCK2 mRNA editing, which was able to increase the stability of DOCK2 mRNA. The in vitro and in vivo data demonstrated that DOCK2 mRNA editing upregulated the expressions of stemness and anti-apoptotic genes by activating Rac1 and then phosphorylating Akt and NF-κB, thus leading to oncogenesis of melanoma stem cells. Our findings contribute new perspectives to miRNA-regulated RNA editing in tumor progression.

YB-1 Structure/Function Relationship in the Packaging of mRNPs and Consequences for Translation Regulation and Stress Granule Assembly in Cells

From their synthesis in the nucleus to their degradation in the cytoplasm, all mRNAs have the same objective, which is to translate the DNA-stored genetic information into functional proteins at the proper time and location. To this end, many proteins are generally associated with mRNAs as soon as transcription takes place in the nucleus to organize spatiotemporal regulation of the gene expression in cells. Here we reviewed how YB-1 (YBX1 gene), one of the major mRNA-binding proteins in the cytoplasm, packaged mRNAs into either compact or extended linear nucleoprotein mRNPs. Interestingly the structural plasticity of mRNPs coordinated by YB-1 could provide means for the contextual regulation of mRNA translation. Posttranslational modification of YB-1, notably in the long unstructured YB-1 C-terminal domain (CTD), and/or the protein partners of YB-1 may play a key role in activation/inactivation of mRNPs in the cells notably in response to cellular stress.

A reciprocal feedback of miR-548ac/YB-1/Snail induces EndMT of HUVECs during acidity microenvironment

Background

Researches indicated the process of Endothelial-Mesenchymal-Transition (EndMT) of vascular endothelial cells (ECs) was critically involved in the progression of tumor. ECs demonstrated functional and phenotypic heterogeneity when located under different microenvironments. The extracellular pH of tumor tissues was acidic compared to that of normal tissues. However, there was still unclear whether the acidic microenvironment affected the EndMT of vascular ECs.

Methods

Human Umbilical Vein Endothelial Cell (HUVECs) was cultured under the normal or acidic medium to evaluate the alteration of morphology, migration, permeability, and EndMT markers. Microarray assay was adopted to analyze the differential expression of miRNAs in the acidity-treated HUVECs. Gain- and loss- of function experiments were performed to evaluate the functional role of miRNA-548ac on acidity-induced EndMT of HUVECs. Luciferase reporter and Chromatin-immunoprecipitation assays were conducted to assess the downstream pathway of miRNA-548ac in acidity-induced EndMT of HUVECs.

Results

Our results showed that HUVECs demonstrated mesenchymal transition under acidic conditions with the increase of migration, permeability, and expression of α-SMA and Vimentin, but the expression of vascular endothelial cadherin (VE-cadherin) and CD31 were reduced. In addition, the acidity-treated HUVECs remarkably facilitated the transmigration of pancreatic cancer cells. The expression of miRNA-548ac was significantly decreased in the acidity-treated HUVECs. Moreover, overexpression of miR-548ac inhibited the EndMT of HUVECs and consequently impeded the transmigration of pancreatic cancer cells. The miR-548ac inhibited the expression of YB-1 by binding to the 3’UTR of its mRNA, and YB-1 promoted the translation of Snail which was a critical regulator of EndMT. What’s more, Snail transcriptionally inhibited the expression of miR-548ac through binding to the promoter of its host gene.

Conclusions

Our data implicated that the acidic microenvironment promoted the EndMT of HUVECs by the miR-548ac/YB-1/Snail axis, which could contribute to the metastasis of pancreatic cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02388-8.

SIRT7 interacts with TEK (TIE2) to promote adriamycin induced metastasis in breast cancer

PURPOSE

Emerging evidence suggests that cytotoxic therapy may promote drug resistance and metastasis while inhibiting the growth of primary tumors. As yet, however, the underlying mechanisms remain unclear. Here, we aimed to investigate the pro-metastatic effects of adriamycin (ADR) therapy on breast cancer cells and to investigate the mechanisms underlying these effects.

METHODS

Differentially expressed genes between MCF-7 and ADR-resistant MCF-7 breast cancer cells were identified using high-throughput RNA-seq and differential gene expression analyses. In vitro transwell and scratch wound-healing assays, and an in vivo spontaneous metastasis model were used to study the metastatic potential of the breast cancer cells. The relationship between SIRT7 and TEK expression was studied using promoter activity, electrophoretic mobility shift (EMSA), CHIP-qPCR and Co-IP assays.

RESULTS

Using transcriptome sequencing, we identified two key genes (SIRT7 and TEK) that might contribute to the pro-metastatic effect of ADR on breast cancer cells. SIRT7 acted as a negative regulator for TEK by inducing deacetylation of H3K18 at the TEK promoter. Through transcription factor prediction and double fluorescence experiments, we found that EST-1 could bind to the TEK promoter. Knockdown of EST-1 removed the transcriptional inhibition of TEK that was mediated by up-regulation of SIRT7. Co-IP showed that SIRT7 interacts directly with EST-1 in breast cancer cells, indicating that SIRT7 may induce H3K18 deacetylation at the TEK promoter region by directly binding to EST-1. In vitro and in vivo results showed that overexpression of SIRT7 or inhibition of TIE2 significantly reduced ADR-dependent breast cancer cell invasion/metastasis.

CONCLUSION

Our findings suggest that ADR therapy may accelerate breast cancer metastasis in a SIRT7/TEK(TIE2) dependent manner.

Potential therapeutic strategies for targeting Y-box-binding protein 1 in cancers

As one of the most conservative proteins in evolution, Y-box-binding protein 1 (YB-1) has long been considered as a potential cancer target. YB-1 is usually poorly expressed in normal cells and exerts cellular physiological functions such as DNA repair, pre-mRNA splicing and mRNA stabilizing. In cancer cells, the expression of YB-1 is up-regulated and undergoes nuclear translocation and contributes to tumorigenesis, angiogenesis, tumor proliferation, invasion, migration and chemotherapy drug resistance. During the past decades, a variety of pharmacological tools such as siRNA, shRNA, microRNA, circular RNA, lncRNA and various compounds have been developed to target YB-1 for cancer therapy. In this review, we describe the physiological characteristics of YB-1 in detail, highlight the role of YB-1 in tumors and summarize the current therapeutic methods for targeting YB-1 in cancer.

A comprehensive review of the functions of YB-1 in cancer stemness, metastasis and drug resistance

The Y Box binding protein 1 (YB-1) is a member of the highly conserved Cold Shock Domain protein family with multifunctional properties both in the cytoplasm and inside the nucleus. YB-1 is also involved in various cellular functions, including regulation of transcription, mRNA stability, and splicing. Recent studies have associated YB-1 with the regulation of the malignant phenotypes in several tumor types. In this review article, we provide an in-depth and expansive review of the literature pertaining to the multiple physiological functions of YB-1. We will also review the role of YB-1 in cancer development, progression, metastasis, and drug resistance in various malignancies, with more weight on literature published in the last decade. The methodology included querying databases PubMed, Embase, and Google Scholar for Y box binding protein 1, YB-1, YBX1, and Y-box-1.

A novel long noncoding RNA, TMEM92-AS1, promotes gastric cancer progression by binding to YBX1 to mediate CCL5

Numerous studies have revealed that long noncoding RNAs (lncRNAs) with oncogene properties play vital roles in gastric cancer (GC). In this study, we aimed to elucidate the function of TMEM92-AS1 in GC progression and to investigate its underlying mechanisms. TMEM92-AS1 was filtered from the Gene Expression Omnibus database. GC tissues and adjacent normal tissues were used to detect the expression level of TMEM92-AS1. MTT, colony-formation assays, Edu, cell cycle, apoptosis and subcutaneous tumour formation assays were used to detect the role of TMEM92-AS1 in cell function. RNA transcriptome sequencing was used to seek downstream target genes. Reverse transcription (RT)-qPCR, western blot, RNA and chromatin immunoprecipitation assays were used to investigate the mechanisms involved. TMEM92-AS1 was significantly overexpressed in GC tissues and correlated with poor overall survival and disease-free survival. Furthermore, TMEM92-AS1 promoted GC cell proliferation and migration in vitro and tumorigenic ability in vivo. RNA transcriptome sequence analysis revealed a potential downstream target gene, C-C motif chemokine ligand 5 (CCL5), and a mechanistic study found that TMEM92-AS1 regulated CCL5 by binding to the transcription factor Y-box binding protein 1(YBX1), which has oncogene properties. In addition, TMEM92-AS1 was found to be associated with peripheral blood leukocyte counts, especially neutrophils. Further investigation found that TMEM92-AS1 may affect leukocytes via regulation of the expression of granulocyte colony-stimulating factor in GC tissues. Our data provide an in-depth insight into the mechanism behind the lncRNA TMEM92-AS1, how it promotes GC progression and the possible mechanism in affecting peripheral leukocyte counts. Therefore, TMEM92-AS1 is a potential target for GC individualized therapy and prognostic assessment.

Requirement of splicing factor hnRNP A2B1 for tumorigenesis of melanoma stem cells

Background

Cancer stem cells play essential roles in tumorigenesis, thus forming an important target for tumor therapy. The hnRNP family proteins are important splicing factors that have been found to be associated with tumor progression. However, the influence of hnRNPs on cancer stem cells has not been extensively explored.

Methods

Quantitative real-time PCR and Western blot were used to examine gene expressions. RNA immunoprecipitation assays were conducted to identify the RNAs interacted with hnRNP A2B1. The in vivo assays were performed in nude mice.

Results

In this study, the results showed that out of 19 evaluated hnRNPs, hnRNP A2B1 was significantly upregulated in melanoma stem cells compared with non-stem cells, suggesting an important role of hnRNP A2B1 in cancer stem cells. Silencing of hnRNP A2B1 triggered cell cycle arrest in G2 phase, leading to apoptosis of melanoma stem cells. The results also revealed that hnRNP A2B1 could bind to the precursor mRNAs of pro-apoptosis genes (DAPK1, SYT7, and RNF128) and anti-apoptosis genes (EIF3H, TPPP3, and DOCK2) to regulate the splicing of these 6 genes, thus promoting the expressions of anti-apoptosis genes and suppressing the expressions of pro-apoptosis genes. The in vivo data indicated that hnRNP A2B1 was required for tumorigenesis by affecting the splicing of TPPP3, DOCK2, EIF3H, RNF128, DAPK1, and SYT7, thus suppressing apoptosis of melanoma stem cells.

Conclusion

Our findings showed the requirement of hnRNP A2B1 for tumorigenesis, thus presenting novel molecular insights into the role of hnRNPs in cancer stem cells.

miRNA in food simultaneously controls animal viral disease and human tumorigenesis

During virus infection in animals, the virus completes its life cycle in a host cell. A virus infection results in the metabolic deregulation of its host and leads to metabolic disorders, ultimately paving the way for cancer progression. Because metabolic disorders in virus infections occurring in animal are similar to metabolic disorders in human tumorigenesis, animal antiviral microRNAs (miRNAs), which maintain the metabolic homeostasis of animal cells, in essence, may have anti-tumor activity in humans. However, that issue has not been investigated. In this study, shrimp miR-34, a potential antiviral miRNA of shrimp against white spot syndrome virus (WSSV) infection, was identified. Overexpression of shrimp miR-34 in shrimp fed bacteria expressing miR-34 suppressed WSSV infection by targeting the viral wsv330 and wsv359 genes. Furthermore, the expression of shrimp miR-34 in mice fed miR-34-overexpressing shrimp suppressed breast cancer progression by targeting human CCND1, CDK6, CCNE2, E2F3, FOSL1, and MET genes. Therefore, our study suggests that the miRNAs in food could be an effective strategy for synchronously controlling viral diseases of economic animals and cancers in humans.

Enrichment of Melanoma Stem-Like Cells via Sphere Assays

Sphere assays are widely used in vitro techniques to enrich and evaluate the stem-like cell behavior of both normal and cancer cells. Utilizing three-dimensional in vitro sphere culture conditions provide a better representation of tumor growth in vivo than the more common monolayer cultures. We describe how to perform primary and secondary sphere assays, used for the enrichment and self-renewability studies of melanoma/melanocyte stem-like cells. Spheres are generated by growing melanoma cells at low density in nonadherent conditions with stem cell media. We provide protocols for preparing inexpensive and versatile polyHEMA-coated plates, setting up primary and secondary sphere assays in almost any tissue culture format and quantification methods using standard inverted microscopy. Our protocol is easily adaptable to laboratories with basic cell culture capabilities, without the need for expensive fluidic instruments.

MicroRNAs at the Crossroad of the Dichotomic Pathway Cell Death vs. Stemness in Neural Somatic and Cancer Stem Cells: Implications and Therapeutic Strategies

Stemness and apoptosis may highlight the dichotomy between regeneration and demise in the complex pathway proceeding from ontogenesis to the end of life. In the last few years, the concept has emerged that the same microRNAs (miRNAs) can be concurrently implicated in both apoptosis-related mechanisms and cell differentiation. Whether the differentiation process gives rise to the architecture of brain areas, any long-lasting perturbation of miRNA expression can be related to the occurrence of neurodevelopmental/neuropathological conditions. Moreover, as a consequence of neural stem cell (NSC) transformation to cancer stem cells (CSCs), the fine modulation of distinct miRNAs becomes necessary. This event implies controlling the expression of pro/anti-apoptotic target genes, which is crucial for the management of neural/neural crest-derived CSCs in brain tumors, neuroblastoma, and melanoma. From a translational point of view, the current progress on the emerging miRNA-based neuropathology therapeutic applications and antitumor strategies will be disclosed and their advantages and shortcomings discussed.

LncRNA LHFPL3-AS1 contributes to tumorigenesis of melanoma stem cells via the miR-181a-5p/BCL2 pathway

Long noncoding RNAs (lncRNAs) are recognized as a new area for cancer therapy. B-cell lymphoma-2 (Bcl-2)-mediated suppression of apoptosis is an important molecular hallmark of cancer. However, the influence of lncRNA on the regulation of oncogenic Bcl-2 in cancer stem cells has not been explored. In this study, our findings revealed that the lncRNA LHFPL3-AS1-long, generated from the polypyrimidine tract binding protein 1 (PTBP1)-mediated splicing of the LHFPL3-AS1 precursor, upregulated BCL2 protein to contribute to tumorigenesis of melanoma stem cells. The in vitro and in vivo results showed that LHFPL3-AS1-long directly interacted with miR-181a-5p to inhibit the mRNA degradation of Bcl-2 (the target of miR-181), thus suppressing apoptosis of melanoma stem cells. The splicing factor PTBP1 regulated the alternative splicing of LHFPL3-AS1 transcript by preferentially binding to the motifs located in exon3 of LHFPL3-AS1 precursor, leading to the biogenesis of LHFPL3-AS1-long in melanoma stem cells. In patients with melanoma, the expressions of PTBP1 and LHFPL3-AS1 were significantly upregulated compared with the healthy donors. Therefore, our study revealed a mechanistic crosstalk among an onco-splicing factor, lncRNA and tumorigenesis of melanoma stem cells, enabling PTBP1 and LHFPL3-AS1 to serve as the attractive therapeutic targets for melanoma.

Shrimp miR-965 induced the human melanoma stem-like cell apoptosis and inhibited their stemness by disrupting the MCL-1-ER stress-XBP1 feedback loop in a cross-species manner

BACKGROUND

Melanoma is a type of aggressive skin cancer with a poor survival rate. The resistance to conventional therapy of this disease is, at least in part, attributed to its cancer stem cell population. However, the mechanism of survival and stemness maintenance of cancer stem cells remains to be investigated.

METHODS

Tumorsphere formation assay was used to study the stem-like property of melanoma stem-like cells (MSLC). Chromatin immunoprecipitation (ChIP), promoter luciferase reporter assay were included for exploring the role of MCL-1 in MSLC and electrophoretic mobility shift assay were used to evaluate the interaction between shrimp miR-965 and human Ago2 protein. Melanoma xenograft nude mice were used to study the inhibition of tumor development.

RESULTS

In the present study, our results showed that myeloid cell leukemia sequence 1 (MCL-1) knocking down induced ER stress and apoptosis, and the expression reduction of stemness associated genes in MSLC, which implied a significant role of MCL-1 in MSLC. Further study indicated that ER stress agonist (tunicamycin) treatment in MSLC results in the translocation of XBP1, an ER stress sensor, into the nucleus to induce MCL-1 expression through direct binding to the - 313- to - 308-bp region of MCL-1 promoter. In addition, we found that a shrimp-derived miRNA (shrimp miR-965) could interact with the human Ago2 protein and suppressed the human MCL-1 expression by binding to the 3' UTR of MCL-1 mRNA, thereby inhibiting the MSLC proliferation and stemness in vitro and in vivo in a cross-species manner.

CONCLUSION

In conclusion, we identified an important role of MCL-1-ER stress-XBP1 feedback loop in the stemness and survival maintenance of MSLC, and shrimp miR-965, a natural food derived miRNA, could regulate MSLC stemness and survival by targeting MCL-1 and disrupting the balance of MCL-1-ER stress-XBP1 feedback loop. In conclusion, this study indicated an important mechanism of the regulation of MSLC stemness and survival, otherwise it also demonstrated the significance of cross-species-derived miRNA as promising natural drugs in melanoma therapy.

Y-Box Binding Proteins in mRNP Assembly, Translation, and Stability Control

Y-box binding proteins (YB proteins) are DNA/RNA-binding proteins belonging to a large family of proteins with the cold shock domain. Functionally, these proteins are known to be the most diverse, although the literature hardly offers any molecular mechanisms governing their activities in the cell, tissue, or the whole organism. This review describes the involvement of YB proteins in RNA-dependent processes, such as mRNA packaging into mRNPs, mRNA translation, and mRNA stabilization. In addition, recent data on the structural peculiarities of YB proteins underlying their interactions with nucleic acids are discussed.

YB-1 interplays with ERα to regulate the stemness and differentiation of ER-positive breast cancer stem cells

Background: Some stemness-associated transcription factors consistently play essential roles in the maintenance of pluripotency or induce the differentiation of cancer stem cells (CSCs). However, the regulatory mechanism of CSC stemness mediated by transcription factors has not been extensively explored. Here, we show that two transcription factors (YB-1 and ERα), which are simultaneously highly expressed in estrogen receptor (ER)-positive CSCs, interact with each other to regulate the stemness and differentiation of ER-positive CSCs.

Methods: The expression of YB-1 was examined in ER-positive CSCs and patient specimens. Western blot, real-time PCR, cell viability analysis, tumorsphere formation assay and subcutaneous tumorigenesis assays were used to study the stemness functions of YB-1 and ERα in CSCs. The relationship between YB-1 and ERα in cells was studied by promoter activity analysis, the electrophoretic mobility shift assay (EMSA) and the Co-IP assay. The mechanisms and functional significance of YB-1 in the sensitivity of CSCs to tamoxifen were further investigated with both in vitro and in vivo models.

Results: YB-1 was aberrantly upregulated in the cancerous tissue of ER-positive breast cancer patients and in CSCs. Knockdown of YB-1 in ER-positive CSCs significantly inhibited cell stemness and induced differentiation, and the expression of YB-1 could be regulated by estrogen signaling and ERα in ER-positive breast CSCs. The Co-IP results showed that YB-1 interacted directly with ERα specifically in ER-positive non-CSCs and that YB-1 induced ERα degradation by ubiquitination via direct interaction in differentiated cells. Cell differentiation induced by FBS could inhibit YB-1 phosphorylation and promote YB-1 protein transfer from the nucleus to the cytoplasm. Moreover, cell differentiation induced by targeting inhibited the expression of YB-1 in ER-positive CSCs, which increased the sensitivity of cells to tamoxifen in vitro and in vivo.

Conclusion: The ERα/YB-1 axis has an important role in the regulation of ER-positive breast cancer stemness. The dephosphorylation of YB-1 and the interaction between YB-1 and ERα may be the switch that initiates the differentiation of ER-positive CSCs. Targeting YB-1 to sensitize ER-positive CSCs to antiestrogen therapy might represent a new therapeutic strategy that warrants further exploration.

Requirement of the transcription factor YB-1 for maintaining the stemness of cancer stem cells and reverting differentiated cancer cells into cancer stem cells

BACKGROUND

Cancer stem cells always express high levels of stemness-associated transcription factors to maintain their features. However, the regulatory mechanism of the stemness of cancer stem cells mediated by transcription factors has not been extensively explored.

METHODS

The YB-1 gene in cancer stem cells was knocked out by the CRISPR/Cas9 system. The YB-1 knockout cancer stem cells were transfected with a vector expressing YB-1 to rescue YB-1, and then the cell proliferation, cell cycle, apoptosis, and stemness, as well as tumorigenesis in nude mice, were assessed to examine the effect of YB-1 in cancer stem cells. The target genes of YB-1 were confirmed by CHIP-seq. The totipotency or pluripotency of differentiated cancer stem cells were detected by tumorsphere formation assay and quantitative real-time PCR.

RESULTS

The deletion of YB-1 gene inhibited the proliferation of breast cancer stem cells and melanoma stem cells, leading to cell cycle arrest and apoptosis, and induced irreversible differentiation of cancer stem cells. The tumorigenicity ability of YB-1-deleted cancer stem cells was significantly reduced in vitro and in vivo. The results of ChIP-seq showed that YB-1 maintained the stemness of cancer stem cells by promoting the expressions of stemness-associated genes (FZD-1, p21, GLP-1, GINS1, and Notch2). Furthermore, simultaneous expressions of YB-1 and the other four (SOX2, POU3F2, OCT-4, and OLIG1) or five (SOX2, SALL2, OCT-4, POU3F2, and Bmi-1) transcription factors in YB-1 knockout cancer stem cells restored the stemness of YB-1 knockout cancer stem cells.

CONCLUSIONS

Our study indicated that YB-1 was required for maintaining the stemness of cancer stem cells and reverting the differentiated tumor cells into cancer stem cells.

miR-34 regulates reproduction by inhibiting the expression of MIH, CHH, EcR, and FAMeT genes in mud crab Scylla paramamosain

Mud crab Scylla paramamosain is a commercially important species widely cultured in China. It is well known that the eyestalk regulates reproductive activities in crustaceans. In our previous research, we found that the miR-34 expression level in male eyestalk was significantly higher than that in females. Thus, we assumed that it may play an important role in regulating reproduction. In this study, we used bioinformatic tools to identify the target genes of miR-34 in eyestalk. Six reproduction-related genes with an intact 3'-untranslated region (UTR), including molt-inhibiting hormone (MIH), crustacean hyperglycemic hormone (CHH), vitellogenesis-inhibiting hormone, red pigment concentrating hormone, ecdysone receptor (EcR), and farnesoic acid methyltransferase (FAMeT) were identified. When the 3'-UTR plasmid vectors of the six genes were cotransfected with miR-34 mimics into 293FT cells, respectively, the luciferase activities of four genes (MIH, CHH, EcR, and FAMeT) were significantly decreased compared with that in the control group; on the contrary, when the six plasmid vectors were cotransfected with the miR-34 inhibitor respectively, the luciferase activities of four genes (MIH, CHH, EcR, and FAMeT) were significantly higher than that in the control group. When agomiR-34 and antagomiR-34 were injected into the eyestalk respectively in vivo, the expression levels of the MIH, CHH, EcR, and FAMeT genes were detected by a quantitative real-time polymerase chain reaction. The results showed that agomiR-34 suppressed the expression of the four genes, whereas antagomiR-34 enhanced their expression. These experimental results confirmed our hypothesis that miR-34 may indirectly regulate reproduction via binding to the 3'-UTRs of MIH, CHH, EcR, and FAMeT genes and suppressing their expression.

A novel long noncoding RNA HOXC-AS3 mediates tumorigenesis of gastric cancer by binding to YBX1

BACKGROUND

Recently, increasing evidence shows that long noncoding RNAs (lncRNAs) play a significant role in human tumorigenesis. However, the function of lncRNAs in human gastric cancer remains largely unknown.

RESULTS

By using publicly available expression profiling data from gastric cancer and integrating bioinformatics analyses, we screen and identify a novel lncRNA, HOXC-AS3. HOXC-AS3 is significantly increased in gastric cancer tissues and is correlated with clinical outcomes of gastric cancer. In addition, HOXC-AS3 regulates cell proliferation and migration both in vitro and in vivo. RNA-seq analysis reveals that HOXC-AS3 knockdown preferentially affects genes that are linked to proliferation and migration. Mechanistically, we find that HOXC-AS3 is obviously activated by gain of H3K4me3 and H3K27ac, both in cells and in tissues. RNA pull-down mass spectrometry analysis identifies that YBX1 interacts with HOXC-AS3, and RNA-seq analysis finds a marked overlap in genes differentially expressed after YBX1 knockdown and those transcriptionally regulated by HOXC-AS3, suggesting that YBX1 participates in HOXC-AS3-mediated gene transcriptional regulation in the tumorigenesis of gastric cancer.

CONCLUSIONS

Together, our data demonstrate that abnormal histone modification-activated HOXC-AS3 may play important roles in gastric cancer oncogenesis and may serve as a target for gastric cancer diagnosis and therapy.

Effect of shRNA Mediated Silencing of YB-1 Protein on the Expression of Matrix Collagenases in Malignant Melanoma Cell In Vitro

Background and Objective: YB-1 is a transcription and oncogenic factor capable of binding to DNA and RNA performing versatile functions within normal and cancer cells. Some studies reported the binding of YB-1 with a collagenases gene promoter and influencing their expression. In addition, the role of YB-1 in malignant melanoma was not elucidated. Thus, in this study, the aim was to knock down the expression of YB-1 in A375 malignant melanoma cancer cell using the shRNA approach and study its effect on cancer cell proliferation, migration, and expression of collagenases. Methods: A375 malignant melanoma cell lines were grown in standard conditions and were transfected with three plasmids containing a retroviral pGFP-V-RS vector, two of them containing targeting sequences for YB-1 mRNA. The third plasmid contained a scrambled mRNA sequence as a negative control. Expression of YB-1 was validated using immune-fluorescence staining, RT-PCR and western blotting. The cancer cell proliferation was determined using MTT assay, serial trypan blue cell counting and cell cycle flow-cytometry analysis. Expression of collagenases (MMP1, MMP8, and MMP13) was evaluated using RT-PCR and western blotting analysis. In addition, a wound-healing assay was used to assess cell migration potential. Statistical analysis was performed using one-way ANOVA test with Bonferroni post hoc analysis to compare the quantitative results among samples. Results: The established silenced cell strains (P1 and P2) had nearly 70% knockdown in the expression of YB-1. These YB-1 silenced strains had a significant cell cycle-specific reduction in cell proliferation (p < 0.05 in serial cell counting and cell cycle flow cytometry analysis, p < 0.001 in MTT assay). In addition, YB-1 silenced strains had a remarkable reduction in cell migration potential. Expression of MMP13 was significantly reduced in YB-1 silenced strains. Conclusion: YB-1 oncoprotein is a promising target in the treatment of malignant melanoma. Silencing of this protein is associated with significant anti-proliferative, anti-invasive and MMP13 insulating properties in A375 malignant melanoma cancer cell lines.