RCC2 promotes breast cancer progression through regulation of Wnt signaling and inducing EMT

PTBP1-mediated biogenesis of circATIC promotes progression and cisplatin resistance of bladder cancer

Background: Cisplatin (DDP) based combination chemotherapy is a vital method for the treatment of bladder cancer (BLca). Chemoresistance easily occurs in the course of cisplatin chemotherapy, which is one of the important reasons for the unfavorable prognosis of BLca patients. Circular RNAs (circRNAs) are widely recognized for their role in the development and advancement of BLca. Nevertheless, the precise role of circRNAs in DDP resistance for BLca remains unclear. Methods: To study the properties of circATIC, sanger sequencing, agarose gel electrophoresis and treatment with RNase R/Actinomycin D were utilized. RT-qPCR assay was utilized to assess the expression levels of circRNA, miRNA and mRNA in BLca tissues and cells. Functional experiments were conducted to assess the function of circATIC in BLca progression and chemosensitivity in vitro. Various techniques such as FISH, Dual-luciferase reporter assay, TRAP, RNA digestion assay, RIP and ChIRP assay were used to investigate the relationships between PTBP1, circATIC, miR-1247-5p and RCC2. Orthotopic bladder cancer model, xenograft subcutaneous tumor model and xenograft lung metastasis tumor model were performed to indicate the function and mechanism of circATIC in BLca progression and chemosensitivity in vivo. Results: In our study, we observed that circATIC expression was significantly enhanced in BLca tissues and cells and DDP resistant cells. Patients with higher circATIC expression have larger tumor diameter, higher incidence of postoperative metastasis and lower overall survival rate. Further experiments showed that circATIC accelerated BLca cell growth and metastasis and induced DDP resistance. Mechanistically, alternative splicing enzyme PTBP1 mediated the synthesis of circATIC. circATIC could enhance RCC2 mRNA stability via sponging miR-1247-5p or constructing a circATIC/LIN28A/RCC2 RNA-protein ternary complex. Finally, circATIC promotes RCC2 expression to enhance Epithelial-Mesenchymal Transition (EMT) progression and activate JNK signal pathway, thus strengthening DDP resistance in BLca cells. Conclusion: Our study demonstrated that circATIC promoted BLca progression and DDP resistance, and could serve as a potential target for BLca treatment.

Promotive actions of lncRNA EBLN3P involved in cervical cancer progression via interacting with miR-29c-3p and TAF15 to modify RCC2

BACKGROUND

Cervical cancer is a common cancer that seriously affects women's health globally. The key roles of long non-coding RNAs (lncRNAs) in the onset and development of cervical cancer have attracted much attention. Our study aims to uncover the roles of lncRNA EBLN3P and miR-29c-3p and the mechanisms by which EBLN3P and miR-29c-3p regulate malignancy in cervical cancer.

METHODS

Tumor and adjacent normal tissues were collected from cervical cancer patients, and the expression of EBLN3P and miR-29c-3p were analyzed via RT-qPCR. The capacities of proliferation, migration, and invasion were assessed using CCK-8, wound healing and transwell assays. The interaction among EBLN3P, miR-29c-3p and TAF15 was determined by luciferase, RNA immunoprecipitation and RNA pull-down assays, respectively. A subcutaneous tumor xenograft mouse model was established to evaluate the functional role of EBLN3P in vivo.

RESULTS

The interaction and reciprocal negative regulation between EBLN3P and miR-29c-3p were uncovered in cervical cancer cells. Likewise, EBLN3P and miR-29c-3p expression patterns in tumor tissues presented a negative association. EBLN3P knockdown weakened cell proliferation, migration and invasion, but these effects were abrogated by miR-29c-3p depletion. Mechanistically, ALKBH5 might impaired EBLN3P stability to reduce its expression. EBLN3P functioned as a competing endogenous RNA (ceRNA) for miR-29c-3p to relieve its suppression of RCC2. Besides, EBLN3P enhanced RCC2 mRNA stability via interacting with TAF15. Furthermore, silencing of EBLN3P repressed the tumor growth in mice.

CONCLUSION

Altogether, lncRNA EBLN3P positively regulates RCC2 expression via competitively binding to miR-29c-3p and interacting with TAF15, thereby boosting proliferation, migration, and invasion of cervical cancer cells.

Wnt/β-catenin-driven EMT regulation in human cancers

Metastasis accounts for 90% of cancer-related deaths among the patients. The transformation of epithelial cells into mesenchymal cells with molecular alterations can occur during epithelial-mesenchymal transition (EMT). The EMT mechanism accelerates the cancer metastasis and drug resistance ability in human cancers. Among the different regulators of EMT, Wnt/β-catenin axis has been emerged as a versatile modulator. Wnt is in active form in physiological condition due to the function of GSK-3β that destructs β-catenin, while ligand-receptor interaction impairs GSK-3β function to increase β-catenin stability and promote its nuclear transfer. Regarding the oncogenic function of Wnt/β-catenin, its upregulation occurs in human cancers and it can accelerate EMT-mediated metastasis and drug resistance. The stimulation of Wnt by binding Wnt ligands into Frizzled receptors can enhance β-catenin accumulation in cytoplasm that stimulates EMT and related genes upon nuclear translocation. Wnt/β-catenin/EMT axis has been implicated in augmenting metastasis of both solid and hematological tumors. The Wnt/EMT-mediated cancer metastasis promotes the malignant behavior of tumor cells, causing therapy resistance. The Wnt/β-catenin/EMT axis can be modulated by upstream mediators in which non-coding RNAs are main regulators. Moreover, pharmacological intervention, mainly using phytochemicals, suppresses Wnt/EMT axis in metastasis suppression.

Long non-coding RNA (LncRNA) non-coding RNA activated by DNA damage (NORAD) knockdown alleviates airway remodeling in asthma via regulating miR-410-3p/RCC2 and inhibiting Wnt/β-catenin pathway

Background

Asthma is a chronic inflammatory disorder with high prevalence in childhood. Airway remodeling, an important structural change of the airways, is resulted from epithelial-mesenchymal transition. Long non-coding RNA non-coding RNA activated by DNA damage (NORAD) has been found to promote epithelial-mesenchymal transition in multiple cancers. This study aimed to analyze the role of NORAD in asthma, mainly focusing on epithelial-mesenchymal transition-mediated airway remodeling, and further explored the NORAD-miRNA-mRNA network.

Methods

NORAD expression was analyzed in transforming growth factor-β1-induced BEAS-2B human bronchial epithelial cells and ovalbumin-challenged asthmatic mice. The influences of NORAD on the epithelial-mesenchymal transition characteristics and Wnt/β-catenin pathway activation were analyzed in vitro. The interactions between NORAD and miR-410-3p as well as miR-410-3p and regulator of chromosome condensation 2 were detected by dual-luciferase reporter assay and RNA pull-down assay. Rescue experiments using miR-410-3p antagonist and chromosome condensation 2 overexpression were used to confirm the mechanism of NORAD. Additionally, the role and mechanism of NORAD were further evaluated in asthmatic mice.

Results

NORAD expression was elevated in both asthmatic models. Knockdown of NORAD impeded spindle-like morphology changes, elevated E-cadherin expression, decreased N-cadherin expression, suppressed cell migration, and inactivated the Wnt/β-catenin pathway in transforming growth factor-β1-stimulated BEAS-2B cells. NORAD acted as a sponge of miR-410-3p to regulate chromosome condensation 2 expression. Rescue assays demonstrated that silencing of NORAD ameliorated transforming growth factor-β1-induced EMT via miR-410-3p/chromosome condensation 2/Wnt/β-catenin axis. In vivo, knockdown of NORAD led to the reduction of inflammatory cell infiltration and collagen deposition, suppression of IL-4, IL-13, transforming growth factor-β1 and immunoglobulin E production, decreasing of N-cadherin, chromosome condensation 2, β-catenin and c-Myc expression, but increasing of E-cadherin and miR-410-3p expression.

Conclusions

Silencing of NORAD alleviated epithelial-mesenchymal transition-mediated airway remodeling in asthma via mediating miR-410-3p/chromosome condensation 2/Wnt/β-catenin pathway.

Multi-ancestry genome-wide meta-analysis identifies novel basal cell carcinoma loci and shared genetic effects with squamous cell carcinoma

Basal cell carcinoma (BCC) is one of the most common malignancies worldwide, yet its genetic determinants are incompletely defined. We perform a European ancestry genome-wide association (GWA) meta-analysis and a Hispanic/Latino ancestry GWA meta-analysis and meta-analyze both in a multi-ancestry GWAS meta-analysis of BCC, totaling 50,531 BCC cases and 762,234 controls from four cohorts (GERA, Mass-General Brigham Biobank, UK Biobank, and 23andMe research cohort). Here we identify 122 BCC-associated loci, of which 36 were novel, and subsequently fine-mapped these associations. We also identify an association of the well-known pigment gene SLC45A2 as well as associations at RCC2 and CLPTM1L with BCC in Hispanic/Latinos. We examine these BCC loci for association with cutaneous squamous cell carcinoma (cSCC) in 16,407 SCC cases and 762,486 controls of European ancestry, and 33 SNPs show evidence of association. Our study findings provide important insights into the genetic basis of BCC and cSCC susceptibility.

RCC2 promotes prostate cancer cell proliferation and migration through Hh/GLI1 signaling pathway and cancer stem-like cells

BACKGROUND

Regulator of chromosome condensation 2 (RCC2) was a telophase disk-binding protein on mitosis, and functions as an oncogene in many human cancers. However, its role on prostate cancer (PCa) was unknown. The goal of this study is to explore the function of RCC 2 on PCa development.

METHODS

The expression of RCC2 and its methylation level, its correlation with lymph node metastasis or disease-free survival (DFS) was analyzed using TCGA database. The effect of RCC2 on PCa cell proliferation, migration and invasion were detected using CCK-8, cell colony formation, Transwell and wood healing assays. RNA-seq and GSEA analysis were used to search the downstream genes and pathways of RCC2 in mediated PCa progression. Western blot was used to detect the proteins in PCa cells transfected with indicated siRNAs or plasmids.

RESULTS

RCC2 had high expression and low promoter methylation level in PCa, and its expression was correlated with regional node metastasis and disease-free survival. Cell proliferation, migration, invasion and EMT of PCa cells in vitro were greatly enhanced after RCC2 overexpression, while the RCC2 knockdown suppressed these processes. RNA-seq and GSEA results showed the Hedgehog signaling regulator Gli1 and Gli3 were involved in RCC2 knockdown DU145 cells. Gli1 was also a marker of cancer stem-like cells (CSCs). Mechanistically, RCC2 induced cell growth, EMT, CSCs markers through Gli1; inhibiting Gli1 expression using siGli1 or GLI inhibitor suppressed cell progression in vitro and tumor growth in vivo.

CONCLUSION

In summary, RCC2 promoted PCa development through Hh/Gli1 signaling pathway via regulating EMT and CSCs.

CCDC3 Gene Regulates the Proliferation of Breast Cancer Cells

We studied the effect of CCDC3 on the viability of human breast cancer cell line MDA-MB-231. The levels of CCDC3 mRNA and the corresponding protein in MDA-MB-231, MCF-7, T-47D, and HCC1937 cell lines were measured by reverse transcription quantitative real-time PCR and Western blotting. Since MDA-MB-231 cells had higher expression of mRNA CCDC3 and CCDC3 protein, we used this cell line for transfection with small interfering RNA by lentivirus. Cell Counting Kit-8 and clone formation assay were used to detect the effects of CCDC3 knockdown on cell viability; flow cytometry was used to detect the effects of CCDC3 knockdown on cell apoptosis and cell cycle. In MDA-MB-231 cell line, the CCDC3 protein level was significantly down-regulated after CCDC3 knockdown in comparison with the control group (p<0.05). The cell viability and the number of clones in the CCDC3 knockdown group were significantly reduced (p<0.05), while the apoptosis rate significantly increased (p<0.05). Thus, after CCDC3 knockdown, cell viability is weakened in MDA-MB-231 cells, and cell apoptosis rate is increased. Therefore, CCDC3 gene is promising as a new candidate target for BC treatment.

Biological functions and molecular interactions of Wnt/β-catenin in breast cancer: Revisiting signaling networks

Changes in lifestyle such as physical activity and eating habits have been one of the main reasons for development of various diseases in modern world, especially cancer. However, role of genetic factors in initiation of cancer cannot be ignored and Wnt/β-catenin signaling is such factor that can affect tumor progression. Breast tumor is the most malignant tumor in females and it causes high mortality and morbidity around the world. The survival and prognosis of patients are not still desirable, although there have been advances in introducing new kinds of therapies and diagnosis. The present review provides an update of Wnt/β-catenin function in breast cancer malignancy. The upregulation of Wnt is commonly observed during progression of breast tumor and confirms that tumor cells are dependent on this pathway Wnt/β-catenin induction prevents apoptosis that is of importance for mediating drug resistance. Furthermore, Wnt/β-catenin signaling induces DNA damage repair in ameliorating radio-resistance. Wnt/β-catenin enhances proliferation and metastasis of breast tumor. Wnt/β-catenin induces EMT and elevates MMP expression. Furthermore, Wnt/β-catenin participates in tumor microenvironment remodeling and due to its tumor-promoting factor, drugs for its suppression have been developed. Different kinds of upstream mediators Wnt/β-catenin signaling in breast cancer have been recognized that their targeting is a therapeutic approach. Finally, Wnt/β-catenin can be considered as a biomarker in clinical trials.

A human pan-cancer system analysis of regulator of chromatin condensation 2

Regulation of chromosome condensation 2 (RCC2) is associated with the cell cycle and is a crucial regulator of the chromatin condensation 1 (RCC1) family. The members of this family were normally regulators in the process of DNA replication and nucleocytoplasmic transport. RCC2 overexpression may lead to tumor formation and poor prognosis in some tumors including breast cancer and lung adenocarcinoma. However, the possible role of RCC2 in tumor formation and its prognostic function remains unclear. In this study, expression analysis from databases including The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC) were combined to perform the first integrative and comprehensive analysis of RCC2 in human pan-cancer. RCC2 was highly expressed in most tumors which may lead to a poor prognosis. RCC2 expression was associated with immune/stromal infiltration, immune checkpoints, tumor mutational burden, and microsatellite instability. Thus, RCC2 could be a novel biomarker for prognosis and a promising cancer therapy target.

LncRNA HOTAIR enhances RCC2 to accelerate cervical cancer progression by sponging miR-331-3p

PURPOSE

Long noncoding RNAs (lncRNAs) have been gradually regarded as influential indicators of various cancers. The present study aimed to identify the effects of lncRNA HOTAIR on cervical cancer progression.

METHODS

RNA and protein expressions were quantified by RT-qPCR and western blot assays. Fluorescence in situ hybridization (FISH) assay was carried out to examine the intracellular location of HOTAIR. Cancer cell viability and mobility were detected by CCK-8, colony formation, transwell and wound healing assays. Binding relationships between miR-331-3p and HOTAIR/RCC2 were validated by luciferase reporter assay.

RESULTS

RT-qPCR assays showed that HOTAIR levels were notably upregulated in cervical cancer tissues and cell lines. Furthermore, a fluorescence in situ hybridization (FISH) assay suggested that HOTAIR was mostly located in the cytoplasm of cancer cells, indicating a sponging function. CCK-8, colony formation, Transwell and wound-healing assays indicated that knockdown of HOTAIR in HeLa and SiHa cells significantly reduced cell growth, migration and invasion. Subsequently, miR-331-3p was proven to be the target molecule of HOTAIR. In addition, results from Pearson's correlation analysis indicated negative correlation between HOTAIR and miR-331-3p in cervical cancer tissues. HOTAIR negatively modulated miR-331-3p expression. Ultimately, the target gene of miR-331-3p was verified to be RCC2, and miR-331-3p negatively modulated RCC2 expression. In addition, analysis on clinical cervical cancer tissues confirmed the negative correlation between miR-331-3p and RCC2. HOTAIR and RCC2 showed oncogenic functions in HeLa and SiHa cells, while miR-331-3p exerted the reverse effect.

CONCLUSIONS

HOTAIR plays a carcinogenic role in cervical cancer by targeting the miR-331-3p/RCC2 axis. Moreover, clinical cervical cancer tissues confirmed the negative correlation between miR-331-3p with lncRNA HOTAIR and RCC2. These data suggested an underlying therapeutic target for cervical cancer.

Comprehensive analysis of the expression profile and clinical implications of regulator of chromosome condensation 2 in pan-cancers

The Regulator of Chromosome Condensation 2 (RCC2) is an important gene that regulates mitosis and cytoplasmic division in the cell cycle. Although there have been reported in several individual tumors, an integrative analysis of RCC2 and its clinical significance across diverse cancer types is poorly elucidated. In this study, we performed integrative bioinformatics analyses to profile the expression landscape and assess the prognostic value of RCC2 in pan-cancers. Correlations between RCC2 expression and tumor-infiltrating immune cells, tumor mutation burden (TMB), microsatellite instability (MSI), chemokine and their receptors were analyzed using TCGA, ESTIMATE algorithm, and TISIDB database. We also explored the potential molecular functions of RCC2 through functional enrichment analysis and protein interaction networks. We discovered that RCC2 was highly expressed in various tumor tissues and was closely associated with cancer prognosis. Different RCC2-associated immune infiltration patterns were exhibited in different tumor-infiltrating immune cells. In addition, the RCC2 had a potential role in regulating the tumor immune microenvironment and the formation of cancer-associated fibroblasts (CAFs). Meanwhile, RCC2 showed a significant correlation with TMB, MSI, chemokines and their receptors in different tumor types. The role of RCC2 as a clinical therapeutic target was further revealed from the perspective of the immune microenvironment. In conclusion, RCC2 is closely associated with tumorigenesis and cancer-immune infiltration, and could be a promising prognostic and therapeutic biomarker in diverse cancers.

Microarray analysis and functional prediction of differentially expressed circular RNAs in acquired middle ear cholesteatoma

BACKGROUND

Middle ear cholesteatoma is characterized by hyper-proliferation of keratinocytes. Circular RNA (circRNA) plays an essential role in the pathogenesis of many proliferative diseases. However, the role of circRNA in the etiopathogenesis of middle ear cholesteatoma is rarely investigated so far. We aimed to investigate the differential expression profiling of circRNAs between acquired middle ear cholesteatoma and normal skin, and to identify potential circRNAs contributing to the etiopathogenesis of middle ear cholesteatoma. Microarray analysis and functional prediction were performed to investigate the circRNA expression profiling between middle ear cholesteatoma and normal skin. Validation of differentially expressed circRNAs was conducted by qRT-PCR. Prediction of m⁶A modification was also carried out.

RESULTS

Microarray analysis displayed that totally 93 up-regulated and 85 down-regulated circRNAs were identified in middle ear cholesteatoma. Through validation, expressions of hsa_circRNA_104327 and hsa_circRNA_404655 were significantly higher, while hsa_circRNA_000319 was significantly down-regulated in cholesteatoma. GO classification, KEGG pathway, and ceRNA network analyses suggested that these differentially expressed circRNAs might play important roles in the etiopathogenesis of middle ear cholesteatoma. Prediction of m⁶A modification exhibited that hsa_circRNA_000319 possessed 4 m⁶A sites with very high confidence, and hsa_circRNA_404655 had 3 m⁶A sites with high confidence.

CONCLUSIONS

Our study revealed that these differentially expressed circRNAs might contribute to the etiopathogenesis of middle ear cholesteatoma. Further researches should be conducted to investigate the exact mechanism of these differentially expressed circRNAs in the etiopathogenesis of middle ear cholesteatoma. Targeting on these circRNAs may provide a new strategy for middle ear cholesteatoma therapy in the future.

LINC01189-miR-586-ZEB1 feedback loop regulates breast cancer progression through Wnt/β-catenin signaling pathway

Non-coding RNAs play essential roles in breast cancer progression by regulating proliferation, differentiation, invasion, and metastasis. However, our understanding of most microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) in breast cancer is still limited. miR-586 has been identified as an important factor in the progression of some types of cancer, but its exact function and relative regulation mechanisms in breast cancer development need to be further investigated. In this study, we showed miR-586 functioned as an oncogene by promoting breast cancer proliferation and metastasis both in vitro and in vivo. Meanwhile, miR-586 induced Wnt/β-catenin activation by directly targeting Wnt/β-catenin signaling antagonists SFRP1 and DKK2/3. Moreover, we demonstrated that LINC01189 functioned as a tumor suppressor and inhibited breast cancer progression through inhibiting an epithelial-mesenchymal transition (EMT)-like phenotype by sponging miR-586. In addition, β-catenin/TCF4 transactivated ZEB1, resulting in a transcriptional repression of LINC01189 expression. In conclusion, our data uncovered the LINC01189-miR-586-ZEB1 feedback loop and provided a novel mechanism participating in the regulation of Wnt/β-catenin signaling in breast cancer progression.

mRBioM: An Algorithm for the Identification of Potential mRNA Biomarkers From Complete Transcriptomic Profiles of Gastric Adenocarcinoma

Purpose

In this work, an algorithm named mRBioM was developed for the identification of potential mRNA biomarkers (PmBs) from complete transcriptomic RNA profiles of gastric adenocarcinoma (GA).

Methods

mRBioM initially extracts differentially expressed (DE) RNAs (mRNAs, miRNAs, and lncRNAs). Next, mRBioM calculates the total information amount of each DE mRNA based on the coexpression network, including three types of RNAs and the protein-protein interaction network encoded by DE mRNAs. Finally, PmBs were identified according to the variation trend of total information amount of all DE mRNAs. Four PmB-based classifiers without learning and with learning were designed to discriminate the sample types to confirm the reliability of PmBs identified by mRBioM. PmB-based survival analysis was performed. Finally, three other cancer datasets were used to confirm the generalization ability of mRBioM.

Results

mRBioM identified 55 PmBs (41 upregulated and 14 downregulated) related to GA. The list included thirteen PmBs that have been verified as biomarkers or potential therapeutic targets of gastric cancer, and some PmBs were newly identified. Most PmBs were primarily enriched in the pathways closely related to the occurrence and development of gastric cancer. Cancer-related factors without learning achieved sensitivity, specificity, and accuracy of 0.90, 1, and 0.90, respectively, in the classification of the GA and control samples. Average accuracy, sensitivity, and specificity of the three classifiers with machine learning ranged within 0.94–0.98, 0.94–0.97, and 0.97–1, respectively. The prognostic risk score model constructed by 4 PmBs was able to correctly and significantly (^∗∗∗p < 0.001) classify 269 GA patients into the high-risk (n = 134) and low-risk (n = 135) groups. GA equivalent classification performance was achieved using the complete transcriptomic RNA profiles of colon adenocarcinoma, lung adenocarcinoma, and hepatocellular carcinoma using PmBs identified by mRBioM.

Conclusions

GA-related PmBs have high specificity and sensitivity and strong prognostic risk prediction. MRBioM has also good generalization. These PmBs may have good application prospects for early diagnosis of GA and may help to elucidate the mechanism governing the occurrence and development of GA. Additionally, mRBioM is expected to be applied for the identification of other cancer-related biomarkers.

Circular RNA FAT atypical cadherin 1 (circFAT1)/microRNA-525-5p/spindle and kinetochore-associated complex subunit 1 (SKA1) axis regulates oxaliplatin resistance in breast cancer by activating the notch and Wnt signaling pathway

Increasing evidence has confirmed the vital roles of circular RNAs (CircRNAs) in the drug resistance of breast cancer (BC). Herein, we intended to study the effect of circular RNA FAT atypical cadherin 1 (circFAT1) on BC oxaliplatin (OX) resistance and find out the potential molecular mechanism in it. In this study, mRNA and protein levels of genes were measured by RT-qPCR and western blotting, respectively. Luciferase reporter assay confirmed the relationship between microRNA-525-5p (miR-525-5p) and circFAT1 or spindle and kinetochore-associated complex subunit 1 (SKA1). CCK-8, transwell, and flow cytometry experiments were utilized to investigate the chemosensitivity, migration, invasion, and apoptosis of BC cells. Gene Set Enrichment Analysis (GSEA) was applied to discover possible pathways related to SKA1. It was uncovered that circFAT1 was overexpressed in OX-resistant BC tissues and cells. Functional experiments showed that circFAT1 depletion reduced the level of chemoresistance-related genes. Moreover, circFAT1 knockdown remarkably facilitated apoptosis and decreased OX (half-maximal inhibitory concentration) IC₅₀ value, migration, and invasion in OX-resistant BC cells. It was identified that miR-525-5p directly targeted circFAT1 and SKA1. Besides, rescue assays exhibited that circFAT1 promoted OX resistance in BC cells via the miR-525-5p/SKA1 regulatory network. Furthermore, GSEA and western blotting identified that SKA1 activated the Notch and Wnt pathway in OX-resistant BC cells. In conclusion, our results demonstrated that circFAT1 conferred OX resistance in BC by regulating the miR-525-5p/SKA1 via the Notch and Wnt pathway, providing a potential therapeutic target for patients with OX-resistant BC.

Roles of regulator of chromosome condensation 2 in cancer: Beyond its regulatory function in cell cycle

Regulator of chromosome condensation 2 (RCC2) is an essential protein in order for mitosis to proceed properly. It localizes in the centrosome of chromosomes where is involved in chromosome segregation and cytokinesis. Furthermore, RCC2 associates with integrin networks at the plasma membrane where participates in the control of cell movement. Because of its known role in cell cycle, RCC2 has been linked with cancer progression. Several reports show that RCC2 induces cancer hallmarks, but the mechanisms explaining how RCC2 exerts these roles are widely unknown. Here, we aim to summarize the main findings explaining the roles and mechanisms of RCC2 in cancer promotion. RCC2 is overexpressed in different cancers, including glioblastoma, lung, ovarian, and esophageal which is related to proliferation, migration, invasion promotion in vitro and tumor progression and metastasis in vivo. Besides, RCC2 overexpression induces epithelial-mesenchymal transition and causes poorer prognosis in cancer patients. RCC2 overexpression has also been linked with resistance development to chemotherapy and radiotherapy by inhibiting apoptosis and activating cancer-promoting transcription factors. Unfortunately, not RCC2 inhibitors are currently available for further pre-clinical and clinical assays. Therefore, these findings emphasize the potential use of RCC2 as a targetable biomarker in cancer and highlight the importance for designing RCC2 chemical inhibitors to evaluate its efficacy in animal studies and clinical trials.

Regulator of Chromosome Condensation 2 Modulates Cell Cycle Progression, Tumorigenesis, and Therapeutic Resistance

Accurate regulation of cell cycle is important for normal tissue development and homeostasis. RCC2 (Regulator of Chromosome Condensation 2) play a role as chromosomal passenger complex (CPC) implicated in all cell cycle phases. RCC2 was initially identified as Ran guanine exchange factor (GEF) for small G proteins. Therefore, RCC2 plays a key role in oncogenesis of most cancers. RCC2 is implicated in Colorectal Cancer (CRC), Lung Adenocarcinoma (LUAD), breast cancer, and ovarian cancer. Expression level of RCC2 protein determines regulation of tumor cell proliferation, invasion, metastasis, and radio-chemotherapeutic resistance. In this review, we explored proteins that interact with RCC2 to modulate tumor development and cancer therapeutic resistance by regulation of cell cycle process through various signaling pathways.

The RAL signaling network: Cancer and beyond

The RAL proteins RALA and RALB belong to the superfamily of small RAS-like GTPases (guanosine triphosphatases). RAL GTPases function as molecular switches in cells by cycling through GDP- and GTP-bound states, a process which is regulated by several guanine exchange factors (GEFs) and two heterodimeric GTPase activating proteins (GAPs). Since their discovery in the 1980s, RALA and RALB have been established to exert isoform-specific functions in central cellular processes such as exocytosis, endocytosis, actin organization and gene expression. Consequently, it is not surprising that an increasing number of physiological functions are discovered to be controlled by RAL, including neuronal plasticity, immune response, and glucose and lipid homeostasis. The critical importance of RAL GTPases for oncogenic RAS-driven cellular transformation and tumorigenesis still attracts most research interest. Here, RAL proteins are key drivers of cell migration, metastasis, anchorage-independent proliferation, and survival. This chapter provides an overview of normal and pathological functions of RAL GTPases and summarizes the current knowledge on the involvement of RAL in human disease as well as current therapeutic targeting strategies. In particular, molecular mechanisms that specifically control RAL activity and RAL effector usage in different scenarios are outlined, putting a spotlight on the complexity of the RAL GTPase signaling network and the emerging theme of RAS-independent regulation and relevance of RAL.

ALDH5A1 acts as a tumour promoter and has a prognostic impact in papillary thyroid carcinoma

Thyroid cancer is the most common endocrine carcinoma, with papillary thyroid carcinoma (PTC) accounting for 80%-90% of thyroid cancers. Accumulating studies reported that mitochondria plays an important role in the regulation of cell proliferation. ALDH5A1, may function as an oncogene or tumour suppressor in various human cancers, and the role of ALDH5A1 in PTC is still unclear. The aim of this study was to investigate the clinical significance of ALDH5A1 expression and its functions in PTC. In this present study, we studied ALDH5A1 expression on primary papillary thyroid carcinoma (PTC) in The Cancer Genome Atlas (TCGA) database. Results showed that the levels of ALDH5A1 were found positively correlated with tumour stage, metastasis, lymph node stage, and higher levels of ALDH5A1 demonstrated poor disease-free survival (DFS). Immunohistochemistry (IHC) revealed that significantly higher expression of ALDH5A1 was found in PTC tissues. On the other hand, knockdown of ALDH5A1 significantly inhibited PTC cell proliferation, migration and invasion detection found the migration and invasion of cells also were hindered when ALDH5A1 level was reduced. The knockdown of ALDH5A1 inhibited the expression of Vimentin and promoted the expression of E-cadherin. In brief, knockdown of ALDH5A1may act as a novel molecular target for the prevention and treatment of PTC. SIGNIFICANCE OF THE STUDY: The present study focused on the role and the potential mechanism of ALDH5A1 in papillary thyroid carcinoma. We demonstrated that reduced expression of ALDH5A1 might inhibit the progression of TC by inhibiting cell proliferation, migration and invasion and reversing epithelial-mesenchymal transition (EMT). The findings ensured the interaction relation between ALDH5A1 and EMT in PTC, providing a novel biological marker for PTC and enriching the potential strategies for TC treatment.

Genomic and epigenetic aberrations of chromosome 1p36.13 have prognostic implications in malignancies

Deletions of chromosome 1p36 are common in malignancies; however, there is limited information regarding the biological and prognostic implications of 1p36 in cancer. Steroid Receptor-Associated and Regulated Protein (SRARP) is a tumor suppressor on chromosome 1p36.13 that its inactivation predicts poor cancer outcome, indicating that the 1p36.13 segment requires further studies. Therefore, a comprehensive multi-omics analysis of The Cancer Genome Atlas (TCGA), the Pan-Cancer Analysis of Whole Genomes (PCAWD), the International Cancer Genome Consortium (ICGC), and the Genomic Data Commons (GDC) Pan-Cancer datasets was conducted to investigate the prognostic implications of 1p36.13 in malignancies. This study revealed that expression and DNA methylation of multiple genes on 1p36.13 are significantly associated with survival in primary tumors and normal adjacent tissues. In addition, copy-number loss in every gene on 1p36.13 predicts poor cancer outcome. Importantly, copy-number loss and somatic mutations of chromosome 1p36.13 segment are associated with worse survival in primary tumors, and DNA hypermethylation of 1p36.13 predicts poor outcome in normal adjacent tissues. Therefore, genomic and epigenetic aberrations of chromosome 1p36.13 have promising prognostic implications in cancer.

RCC2 Promotes Esophageal Cancer Growth by Regulating Activity and Expression of the Sox2 Transcription Factor

Regulator of chromosome condensation 2 (RCC2) is a protein located in the centrosome, which ensures that cell division proceeds properly. Previous reports show that RCC2 is overexpressed in some cancers and could play a key role in tumor development, but the mechanisms concerning how this occurs are not understood. Furthermore, no evidence exists regarding its role in esophageal cancer. We studied the relevance of RCC2 in esophageal cancer growth and its regulation on Sox2, an important transcription factor promoting esophageal cancer. RCC2 was overexpressed in esophageal tumors compared with normal tissue, and this overexpression was associated with tumorigenicity by increasing cell proliferation, anchorage-independent growth, and migration. These oncogenic effects were accompanied by overexpression of Sox2. RCC2 upregulated and stabilized Sox2 expression and its target genes by inhibiting ubiquitination-mediated proteasome degradation. Likewise, RCC2 increased the transcriptional activity and promoter binding of Sox2. In vivo studies indicated that RCC2 and Sox2 were overexpressed in esophageal tumors compared with normal tissue, and this upregulation occurs in the esophageal basal cell layer for both proteins. In conditional knockout mice, RCC2 deletion decreased the tumor nodule formation and progression in the esophagus compared with wild-type mice. Proliferating cell nuclear antigen expression, a cell proliferation marker, was also downregulated in RCC2 knockout mice. Overall, our data show for the first time that RCC2 is an important protein for the stabilization and transcriptional activation of Sox2 and further promotion of malignancy in esophageal cancer. IMPLICATIONS: This study shows that RCC2 controls Sox2 expression and transcriptional activity to mediate esophageal cancer formation.

RCC2 Expression Stimulates ER-Positive Breast Tumorigenesis

Objective

Regulator of chromosome condensation 2 (RCC2) has been reported to be involved in the regulation of cell cleavage. This study investigated the effect of RCC2 expression on breast tumorigenesis.

Methods

MCF-7 cells originating from estrogen receptor-positive (ER+) breast cancer were transfected with anti-RCC2 siRNA or RCC2-expressing plasmids. Cell proliferation, apoptosis, migration, and cytokine production in the transfected cells were examined using the CCK-8 assay, wound healing assay, and flow cytometry, respectively. PCR array was used to investigate the tumorigenic pathway of RCC2 in MCF-7 cells transfected with the anti-RCC2 siRNA. MCF-7 cells were also transfected with lentivirus-containing anti-RCC2 short hairpin RNA and were injected into BALB/c nude mice to generate tumor-bearing mice. Tumor growth in the mouse model was examined using magnetic resonance imaging by diffusion-weighted imaging analysis.

Results

Western blotting and immunohistochemistry detected significantly increased expression of RCC2 in ER + breast tumor tissues compared with breast fibroadenoma samples. Inhibiting RCC2 expression decreased cell migration and stimulated apoptosis in MCF-7 cells, while overexpressing RCC2 stimulated cell migration and inhibited apoptosis. The inhibition of RCC2 expression significantly decreased breast tumor growth and IL-6 levels in the tumor-bearing mice. PCR array demonstrated that inhibiting RCC2 expression significantly decreased the expression of IGF1 and TWIST1, two well-known tumor-enhancing genes, in MCF-7 cells; conversely, overexpressing RCC2 increased the expression levels of these two genes in the transfected cells. This result was verified in the mouse model following inhibition of RCC2 expression in MCF-7 cells. Additionally, estradiol-17β suppressed MCF-7 cell apoptosis, stimulated cell proliferation and cell migration, and increased RCC2, IGF1, and TWIST1 expression. The siRNA-mediated inhibition of RCC2 expression alleviated the inhibitory effects of estrogen on apoptosis in MCF-7 cells, while overexpressing RCC2 enhanced the estrogen-driven inhibition of apoptosis. Modifying RCC2 expression had no impact on MCF-7 cell proliferation in the presence or absence of estradiol-17β.

Conclusions

Our results suggest that estrogen-induced RCC2 expression prompts IGF1, TWIST1, and IL-6 expression, stimulates cell migration, and inhibits apoptosis to contribute to ER + breast tumorigenesis.

Overexpression of NuSAP1 is predictive of an unfavourable prognosis and promotes proliferation and invasion of triple-negative breast cancer cells via the Wnt/β-catenin/EMT signalling axis

OBJECTIVE

We analysed the effect of expression of nucleolar spindle-associated protein 1 (NuSAP1) on the prognosis of breast cancer (BC) and investigated its potential mechanism of tumourigenicity in triple-negative breast cancer (TNBC) cell lines.

MATERIALS AND METHODS

We downloaded the RNA-seq breast cancer (BC) data from The Cancer Genome Atlas (TCGA) and screened for the NuSAP1 gene using R software. The clinical data for patients with BC were screened and analysed using R software. A survival curve was drawn using the Kaplan-Meier Plotter. Cell proliferation and invasion were verified by the Cell Counting Kit-8 and Transwell assays. Expression of NuSAP1, the Wnt/β-catenin pathway, and epithelial-mesenchymal-transition-related proteins in TNBC was detected using real-time quantitative polymerase chain reaction (qRT-PCR) and western blotting (WB).

RESULTS

Expression of NuSAP1 was upregulated in BC. The change in NuSAP1 expression levels was associated with multiple clinicopathological factors, and the higher the expression of NuSAP1 was, the shorter the survival time. In MDA-MB-231 and BT549 cells, knockdown of NuSAP1 expression resulted in a significant decrease in cell proliferation and invasion; a decrease in expression of cyclin D1, vimentin, Slug, Twist, wnt3a, and pβ-catenin; and an increase in expression of e-cadherin. The results of the sh-NuSAP1 + ov-NuSPA1 group were the opposite of the results of the sh-NuSAP1 group.

CONCLUSION

NuSAP1 is a carcinogen that facilitates progression of TNBC through the Wnt/β-catenin and epithelial-mesenchymal transition pathways.