Cancer Cell Cycle Progression Research Articles

SLC7A5 correlated with malignancies and immunotherapy response in bladder cancer

BackgroundMetabolic reprogramming contributes to bladder cancer development. This study aimed to understand the role of SLC7A5 in bladder cancer.MethodsWe systematically analyzed the correlation between SLC7A5 and bladder cancer through various approaches, including bioinformatics, western blotting, cell cycle analysis, cell proliferation assays, and invasion experiments. We also investigated the immunological features within the tumor microenvironment (TME), encompassing cancer immune cycles, immune modulators, immune checkpoints, tumor-infiltrating immune cells (TIIC), T cell inflammation scores, and treatment responses. Additionally, for a comprehensive assessment of the expression patterns and immunological roles of SLC7A5, pan-cancer analysis was performed using cancer genomics datasets.ResultsSLC7A5 was associated with adverse prognosis in bladder cancer patients, activating the Wnt pathway and promoting bladder cancer cell cycle progression, proliferation, migration, and invasion. Based on the evidence that SLC7A5 positively correlated with immunomodulators, TIIC, the cancer immune cycle, immune checkpoint and T cell inflammation scores, we also found that SLC7A5 was associated with the inflammatory tumor immune microenvironment. EGFR-targeted therapy, cancer immunotherapy, and radiation therapy were effective for patients with high SLC7A5 expression in bladder cancer. Low SLC7A5 patients were, however, sensitive to targeted therapies and anti-angiogenic therapy, such as blocking β-catenin network, PPAR-γ and FGFR3 signaling. Anti-SLC7A5 combined with cancer immunotherapy may have greater effectiveness than either therapy alone. Furthermore, we observed specific overexpression of SLC7A5 in TME of various cancers.ConclusionSLC7A5 can predict therapeutic response to immunotherapy, radiotherapy and chemotherapy in bladder cancer patients. Targeting SLC7A5 in combination with immunotherapy may be a potentially appropriate treatment option.

An exosomes-related lncRNA prognostic model correlates with the immune microenvironment and therapy response in lung adenocarcinoma

Recent research highlights the significance of exosomes and long noncoding RNAs (lncRNAs) in cancer progression and drug resistance, but their role in lung adenocarcinoma (LUAD) is not fully understood. We analyzed 121 exosome-related (ER) mRNAs from the ExoBCD database, along with mRNA and lncRNA expression profiles of TCGA-LUAD using “DESeq2”, “survival,” “ConsensusClusterPlus,” “GSVA,” “estimate,” “glmnet,” “clusterProfiler,” “rms,” and “pRRophetic” R packages. This comprehensive approach included univariate cox regression, unsupervised consensus clustering, GSEA, functional enrichment analysis, and prognostic model construction. Our study identified 134 differentially expressed ER-lncRNAs, with 19 linked to LUAD prognosis. These ER-lncRNAs delineated two patient subtypes, one with poorer outcomes. Additionally, 286 differentially expressed genes were related to these ER-lncRNAs, 261 of which also correlated with LUAD prognosis. We constructed an ER-lncRNA-related prognostic model and calculated an ER-lncRNA-related risk score (ERS), revealing that a higher ERS correlates with poor overall survival in both the Meta cohort and two validation cohorts. The ERS potentially serves as an independent prognostic factor, and the prognostic model demonstrates superior predictive power. Notably, significant differences in the immune landscape were observed between the high- and low-ERS groups. Drug sensitivity analysis indicated varying responses to common chemotherapy drugs based on ERS stratification, with the high-ERS group showing greater sensitivity, except to rapamycin and erlotinib. Experimental validation confirmed that thymidine kinase 1 enhances lung cancer invasion, metastasis, and cell cycle progression. Our study pioneers an ER-lncRNA-related prognostic model for LUAD, proposing that ERS-based risk stratification could inform personalized treatment strategies to improve patient outcomes.

Prognostic significance and immune landscape of a cell cycle progression-related risk model in bladder cancer

BackgroundA greater emphasis has been placed on the part of cell cycle progression (CCP) in cancer in recent years. Nevertheless, the precise connection between CCP-related genes and bladder cancer (BCa) has remained elusive. This study endeavors to establish and validate a reliable risk model incorporating CCP-related factors, aiming to predict both the prognosis and immune landscape of BCa.MethodsClinical information and RNA sequencing data were collected from the GEO and TCGA databases. Univariate and multivariate Cox regression analyses were conducted to construct a risk model associated with CCP. The performance of the model was assessed using ROC and Kaplan–Meier survival analyses. Functional enrichment analysis was employed to investigate potential cellular functions and signaling pathways. The immune landscape was characterized using CIBERSORT algorithms. Integration of the risk model with various clinical variables led to the development of a nomogram.ResultsTo build the risk model, three CCP-related genes (RAD54B, KPNA2, and TPM1) were carefully chosen. ROC and Kaplan–Meier survival analysis confirm that our model has good performance. About immunological infiltration, the high-risk group showed decreased levels of regulatory T cells and dendritic cells coupled with increased levels of activated CD4 + memory T cells, M2 macrophages, and neutrophils. Furthermore, the nomogram showed impressive predictive power for OS at 1, 3, and 5 years.ConclusionThis study provides new insights into the association between the CCP-related risk model and the prognosis of BCa, as well as its impact on the immune landscape.

Role of β3 subunit of the GABA type A receptor in triple negative breast cancer proliferation, migration, and cell cycle progression

ABSTRACT Triple negative breast cancer (TNBC) is known for its heterogeneous nature and aggressive onset. The unresponsiveness to hormone therapies and immunotherapy and the toxicity of chemotherapeutics account for the limited treatment options for TNBC. Ion channels have emerged as possible therapeutic candidates for cancer therapy, but little is known about how ligand gated ion channels, specifically, GABA type A ligand-gated ion channel receptors (GABAAR), affect cancer pathogenesis. Our results show that the GABAA β3 subunit is expressed at higher levels in TNBC cell lines than non-tumorigenic cells, therefore contributing to the idea that limiting the GABAAR via knockdown of the GABAA β3 subunit is a potential strategy for decreasing the proliferation and migration of TNBC cells. We employed pharmacological and genetic approaches to investigate the role of the GABAA β3 subunit in TNBC proliferation, migration, and cell cycle progression. The results suggest that pharmacological antagonism or genetic knockdown of GABAA β3 subunit decreases TNBC proliferation and migration. In addition, GABAA β3 subunit knockdown causes cell cycle arrest in TNBC cell lines via decreased cyclin D1 and increased p21 expression. Our findings suggest that membrane bound GABAA receptors containing the β3 subunit can be further developed as a potential novel target for the treatment of TNBC.

Abstract P48: Advancing Personalized Anti-Cancer Pharmacotherapy: Magnetic Bioprinting of a Ductal Drug Screening Platform for Salivary Gland Mucoepidermoid Carcinoma

Abstract Mucoepidermoid carcinoma (MEC) is the most common malignant neoplasm of the salivary glands (SG), and it arises from “reserve” stem cells within the ductal network. Recently, our research team has consistently generated acinar-like epithelial SG organoids using a magnetic three-dimensional bioprinting (M3DB) platform. However, 3D ductal constructs with lumenized and functional features have not been established by biofabrication strategies due to challenges related to the lack of epithelial polarity and reproducibility. Consequently, our research unit is developing an in vitro high throughput drug screening platform with bio-printed ductal constructs as avatars of MEC ductal units towards a more effective and personalized anti-cancer pharmacotherapy. M3DB, multiplex immunofluorescence, western blot, and functional assays were performed. M3DB induced the formation of ring-like organoid 3D constructs after the magnetic bioassembly of MEC HTB41 cells overnight. These bio-printed constructs had a lumen formation efficiency of ~70% and contained functional E-cadherin+ cell clusters expressing ZO-1 with mainly K14+ and K5+ ductal progenitor populations with high pro-mitotic activity (Ki-67). These bio-printed ductal-like constructs were then proteomic and functionally evaluated in the presence or absence of 5-fluorouracil (5-FU), a chemotherapy drug. Proteomic assessments revealed changes in cellular antioxidant response (Nrf2) as well as DNA damage repair (γ-H2AX) after 5-FU exposure, potentially safeguarding cells from damage and halting cancer cell cycle progression. Tumor cell invasion capabilities within co-culture in mili-fluidic platforms, and functional evaluation with cholinergic and adrenergic agonists and swelling assays confirmed the 5-FU-induced cytotoxicity, decreased invasion potential, and ductal hypofunction. In summary, our team successfully established novel bio-printed MEC ductal-like avatar platforms that will pave the way for personalized pharmacotherapy and precision oncology in SG malignant tumors. Citation Format: Yamin Oo, Tien T.T. Truong, Toan V. Phan, Khurshid Ahmed, Teerapat Rodboon, Risa Chaisuparat, Glauco R. Souza, Joao N. Ferreira. Advancing Personalized Anti-Cancer Pharmacotherapy: Magnetic Bioprinting of a Ductal Drug Screening Platform for Salivary Gland Mucoepidermoid Carcinoma [abstract]. In: Proceedings of Frontiers in Cancer Science; 2023 Nov 6-8; Singapore. Philadelphia (PA): AACR; Cancer Res 2024;84(8_Suppl):Abstract nr P48.

Progerin Inhibits the Proliferation and Migration of Melanoma Cells by Regulating the Expression of Paxillin.

Progerin, the underlying cause of Hutchinson-Gilford Progeria Syndrome (HGPS), has been extensively studied for its impact on normal cells and premature aging patients. However, there is a lack of research on its specific effects on tumor cells. Melanoma is one of the most common malignant tumors with high morbidity and mortality. This study aimed to elucidate the potential therapeutic role of progerin in melanoma. We constructed the melanoma A375 cell line and M14 cell line with stable expression of progerin. The expression of progerin, paxillin, and epithelial-mesenchymal transition (EMT) marker proteins in each cell group was measured using Western blot. The migration, proliferation, and cell cycle of cancer cells were assessed using the transwell assay, wound healing assay, colony formation assay, CCK 8 assay, and flow cytometry. RT-qPCR technology was used to examine the impact of progerin overexpression on microRNA expression. Finally, we transfected paxillin into the progerin overexpression cell group to verify whether progerin regulates the phenotype of tumor cells through paxillin. Our study demonstrated that overexpression of progerin leads to decreased expression of paxillin and inhibits cancer cell migration, proliferation, EMT process and cell cycle progression. Additionally, rescue experiments revealed that the migration, proliferation ability, and EMT marker protein expression in progerin overexpressing cancer cells could be partially restored by transfecting a plasmid containing the paxillin gene. Mechanistic investigations further revealed that progerin achieves this inhibition of paxillin expression by upregulating miR-212. This study reveals that progerin may inhibit the migration and proliferation of melanoma cells through the miR-212/paxillin axis, which provides a new approach for the future treatment of this disease.

PCID2 is highly expressed in gastric cancer and affects the prognosis by regulating cancer cell cycle and proliferation

To investigate the expression of PCI Domain Containing 2 (PCID2) in gastric cancer, its effect on gastric cancer cell cycle and proliferation and the possible molecular mechanisms. We examined PCID2 expression levels in gastric cancer and adjacent tissues from 100 patients undergoing radical gastrectomy in our hospital between January, 2012 and December, 2016, and analyzed the correlation of PCID2 expression level with cancer progression and postoperative 5-year survival rate of the patients. GO enrichment analysis was performed to identify the possible pathways that mediated the effect of PCID2 in gastric cancer progression. The effects of lentivirus-mediated PCID2 knockdown and overexpression on cell proliferation and cell cycle were analyzed in gastric cancer MGC-803 cells and in nude mice. PCID2 was highly expressed in gastric cancer tissues and positively correlated with peripheral blood levels of CA19-9 and CEA (P < 0.01). In gastric cancer patients, a high PCID2 expression was associated with a significantly lowered postoperative 5-year survival rate (P < 0.001) as an independent risk factor for postoperative survival (HR: 2.987, 95% CI: 1.616-5.519). The sensitivity, specificity, and area under the curve of PCID2 for predicting postoperative 5-year survival were 76.74%, 75.44%, and 0.755 (P < 0.001), respectively. GO enrichment analysis suggested that PCID2 was associated with gastric cancer cell cycle progression. PCID2 overexpression in MGC-803 cells significantly promoted cell proliferation, G1/S phase transition, expressions of cyclin D1 and CDK6, and the growth of transplanted xenograft in nude mice (P < 0.05). The expressions of p27 and p16 were significantly lowered in gastric cancer tissues, and their expression levels were negatively regulated by PCID2 expression in MGC-803 cells (P < 0.05). PCID2 is highly expressed in gastric cancer tissues in close correlation with poor prognosis of the patients. High PCID2 expression promotes gastric cancer proliferation and cell cycle progression by inhibiting the expression of p27 and p16.

RNF115 aggravates tumor progression through regulation of CDK10 degradation in thyroid carcinoma

BackgroundRING Finger Protein 115 (RNF115), a notable E3 ligase, is known to modulate tumorigenesis and metastasis. In our investigation, we endeavor to unravel the putative function and inherent mechanism through which RNF115 influences the evolution of thyroid carcinoma (THCA).MethodsWe analyzed RNF115 expression in THCA using the Cancer Genome Atlas (TCGA) database. The influence of RNF115 on the progression of THCA was evaluated using both in vitro and in vivo experimental approaches. The protein regulated by RNF115 was identified through bioinformatics analysis, and its biological significance was further explored.ResultsIn both THCA tissues and cells, RNF115 showed elevated expression levels. Enhanced expression of RNF115 fostered cell proliferation, tumor growth, and the exacerbation of epithelial-mesenchymal transition (EMT) in THCA, while also promoting tumor lung metastasis. Bioinformatics analysis identified cyclin-dependent kinase 10 (CDK10) as a downstream target of RNF115, which was found to be ubiquitinated and degraded by RNF115 in THCA cells. Functionally, overexpression of CDK10 was found to counteract the promotion of malignant phenotype in THCA induced by RNF115. From a mechanistic perspective, RNF115 activated the Raf-1 pathway and enhanced cancer cell cycle progression by degrading CDK10 in THCA cells.ConclusionRNF115 triggers cell proliferation, EMT, and tumor metastasis by ubiquitinating and degrading CDK10. The regulation of the Raf-1 pathway and cell cycle progression in THCA may be profoundly influenced by this process.

IGF2BP2 Drives Cell Cycle Progression in Triple-Negative Breast Cancer by Recruiting EIF4A1 to Promote the m6A-Modified CDK6 Translation Initiation Process.

IGF2BP2 is a new identified N6-methyladenosine (m6A) reader and associated with poor prognosis in many tumors. However, its role and related mechanism in breast cancer, especially in triple-negative breast cancer (TNBC), remains unclear. In this study, it is found that IGF2BP2 is highly expressed in TNBC due to the lower methylation level in its promoter region. Functional and mechanical studies displayed that IGF2BP2 could promote TNBC proliferation and the G1/S phase transition of the cell cycle via directly regulating CDK6 in an m6A-dependent manner. Surprising, the regulation of protein levels of CDK6 by IGF2BP2 is related to the changes in translation rate during translation initiation, rather than mRNA stability. Moreover, EIF4A1 is found to be recruited by IGF2BP2 to promote the translation output of CDK6, providing new evidence for a regulatory role of IGF2BP2 between m6A methylation and translation. Downregulation of IGF2BP2 in TNBC cell could enhance the sensitivity to abemaciclib, a CDK4/6 inhibitor. To sum up, our study revealed IGF2BP2 could facilitate the translation output of CDK6 via recruiting EIF4A1 and also provided a potential therapeutic target for the diagnosis and treatment of TNBC, as well as a new strategy for broadening the drug indications for CDK4/6 inhibitors.

Retracted] Tripartite motif‑containing 14 regulates cell proliferation and apoptosis in cervical cancer via the Akt signaling pathway.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the GAPDH control western blotting data shown in Fig.2B were strikingly similar to data appearing in different form in Fig.1E in another article written by different authors at different research institutes [LiangT, Ye X, Liu Y, Qiu X, Li Z, TianB and YanD: FAM46B inhibits cell proliferation and cell cycle progression in prostate cancer through ubiquitination of β‑catenin. Exp Mol Med50: 1‑12, 2018]. Owing to the fact that the contentious data in the above article had already been published prior to its submission to Molecular Medicine Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 22: 5145‑5154, 2020; DOI: 10.3892/mmr.2020.11634].

QSAR, Molecular Docking &amp; ADMET Studies of Pyrrolo[2,3-d] Pyrimidine Derivatives as CDK4 Inhibitors for the Treatment of Cancer

Background:: Cancer is caused by dysregulation of the cell cycle, which results in abnormal proliferation and the inability of cells to differentiate or die. Cyclins and cyclin-dependent kinases (CDK4) inhibitors are drugs that target a specific enzyme, CDK4 that controls cell cycle progression in cancer. Aim &amp; Objective:: The aim of this study is to obtain an optimized pharmacophore of pyrrolo[2,3-d] pyrimidine as a CDK4 inhibitor using QSAR studies. This aids in determining the link between structure and activity in newly developed chemical entities (NCE’s). To perform molecular docking and ADMET analysis to determine the binding affinity and drug-likeness of NCE’s. Materials and Methods:: The Multiple linear regression approach (MLR) method was utilised to generate the QSAR Model using the programme QSARINS v.2.2.4. For molecular docking, the Autodock vina software was employed. While the Swiss ADME and ToxiM online tools were used to predict toxicity. Results and Discussion:: The best models generated for 2D QSAR had correlation coefficients of R2= 0.9247 &amp; Q2= 0.924 and for 3D QSAR, coefficients were R2 = 0.9297 and Q2 = 0.876. A novel series of 68 derivatives was designed based on QSAR investigations. Molecule C-58 has shown maximum binding affinity in molecular docking as compared to the standard Ribociclib. result: For 2D QSAR, the best models produced has correlation coefficients of R2= 0.9247 and Q2= 0.924. The 3D-QSAR model obtained with R2= 0.9297 and Q2 = 0.876. Based on QSAR studies, a new series of 68 derivatives was generated Conclusion:: Fifteen compounds have shown potential as CDK4 inhibitors based on docking studies, pharmacokinetic behavior and toxicity profile. The maximum binding affinity was demonstrated by molecule C-58. other: N/A

ELK4 Promotes Cell Cycle Progression and Stem Cell-like Characteristics in HPV-associated Cervical Cancer by Regulating the FBXO22/PTEN Axis

Cervical cancer (CC) is a prevalent gynecological carcinoma, and patients infected with human papillomavirus (HPV) have a higher morbidity rate. To explore the effects of ETS-like transcription factor 4 (ELK4) in patients with HPV+ CC. In vitro cell lines and human-sample study. The ELK4 levels in human tissue (65 HPV+ CC tissue and 25 HPV− normal cervical tissue) and cell lines (human cervical epithelial immortalized cell line H8 and CC cell lines HeLa [HPV18], CaSki [HPV16], and SiHa [HPV−]) were quantified using qRT-PCR and western blot assay. ELK4 knockdown transfection was effective and confirmed by western blotting. The MTT and EDU assays were used to evaluate cell viability and proliferation, respectively. Flow cytometry was used to detect the CC cell cycle stage. Stem cell markers, such as cluster of differentiation 133 (CD133), CD44, and aldehyde dehydrogenase 1, and the cervicospheres formed were measured. ChIP-qPCR and luciferase activity experiments were used to assess the bond between ELK4 and F-box protein 22 (FBXO22). ELK4 was highly expressed in the HPV+ CC tissue. CC cells with ELK4 knockdown had lower viability and proliferation than the control cells. ELK4 knockdown blocked the progression of the cell cycle from G1 to S phase. ELK4 knockdown suppressed the stem cell-like characteristics of the HPV+ CC cells. ELK4 bonded with the FBXO22 promoter, inhibiting the levels of phosphatase and tensin homolog (PTEN). ELK4 facilitated cell cycle progression and stem cell-like characteristics by regulating the FBXO22/PTEN axis. Thus, ELK4 could be a potential therapeutic target to arrest the progress of HPV-associated CC.

LncRNA EILA promotes CDK4/6 inhibitor resistance in breast cancer by stabilizing cyclin E1 protein.

CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy are now standard first-line therapy for advanced HR+/HER2- breast cancer, but developing resistance is just a matter of time in these patients. Here, we report that a cyclin E1-interacting lncRNA (EILA) is up-regulated in CDK4/6i-resistant breast cancer cells and contributes to CDK4/6i resistance by stabilizing cyclin E1 protein. EILA overexpression correlates with accelerated cell cycle progression and poor prognosis in breast cancer. Silencing EILA reduces cyclin E1 protein and restores CDK4/6i sensitivity both in vitro and in vivo. Mechanistically, hairpin A of EILA binds to the carboxyl terminus of cyclin E1 protein and hinders its binding to FBXW7, thereby blocking its ubiquitination and degradation. EILA is transcriptionally regulated by CTCF/CDK8/TFII-I complexes and can be inhibited by CDK8 inhibitors. This study unveils the role of EILA in regulating cyclin E1 stability and CDK4/6i resistance, which may serve as a biomarker to predict therapy response and a potential therapeutic target to overcome resistance.

Evaluation of anti-cancer effects of carnosine and melittin-loaded niosomes in MCF-7 and MDA-MB-231 breast cancer cells.

Background: We investigated the anti-cancer effect of carnosine-loaded niosomes (Car-NIO) and melittin-loaded niosomes (Mel-NIO) with olaparib in breast cancer cell lines (MCF-7 and MDA-MB-231). Methods: The thin film method was used for preparing the niosomes and characterized in terms of morphology, size, and polydispersity index (PDI). We further evaluated the impact of these peptides on breast cancer cells viability, RT-qPCR assays, malondialdehyde (MDA) activity, and cell cycle progression, to determine if these are linked to carnosine and melittin's anti-proliferative properties. Results: Car-NIO and Mel-NIO in vitro study inhibited cancer cell viability. They have also upregulated the expression of protein 53 (P53), BCL2-Associated X Protein (Bax), caspase-9, caspase-3, programmed cell death 4 (PDCD4), and Forkhead box O3 (FOXO3), while downregulated the expression of B-cell lymphoma 2 (Bcl2), poly (ADP-ribose) polymerase (PARP 1), and MicroRNA-183 (miRNA-183). The MCF-7 cells were arrested at the G2/M phase in Car-NIO, on the other hand, the MDA-MB-231 cells were arrested at the S phase. While the Mel-NIO and olaparib arrested the MCF-7 and MDA-MB-231 cells at the G0/1 phase. Conclusion: Our study successfully declared that Mel-NIO had more anti-cancer effects than Car-NIO in both MCF-7 and MDA-MB-231 breast cancer cells.

High expression of MRPL13 promotes cell cycle progression and proliferation of gastric cancer cells by inhibiting p53 signaling to affect long-term prognosis

To determine the expression of mitochondrial ribosomal protein L13 (MRPL13) in gastric cancer and its impact on long-term prognosis and explore the possible mechanism. We analyzed MRPL13 expression level in gastric cancer and its association with the patients' prognosis based on the public cancer database the data of 100 gastric cancer patients undergoing radical gastrectomy in our hospital from January, 2014 to October, 2017. We further assessed the effects of MRPL13 overexpression and knockdown on proliferation and cell cycle of gastric cancer MGC-803 and SGC-7901 cells in vitro and on subcutaneous xenograft growth in nude mice. Both bioinformatic analysis and the patients' data demonstrated that the expression level of MRPL13 was significantly higher in gastric cancer than in adjacent tissues (P<0.05) and positively correlated with peripheral blood Ki67, CEA and CA19-9 levels (P<0.05). High expression of MRPL13 was an independent risk factor affecting the 5-year survival rate of gastric cancer patients (HR: 3.284; 95% CI: 1.537-7.016). Gene set enrichment analysis suggested that MRPL13 was involved in cell cycle and p53 signaling. In cultured gastric cancer cells, MRPL13 overexpression significantly promoted cell proliferation, G1/S phase transition and the expressions of cyclin D1 and CDK6 (P<0.05), and MRPL13 knockdown produced the opposite effects (P<0.05). MRPL13 overexpression significantly promoted gastric cancer cell xenograft growth (P<0.05), and MRPL13 knockdown obviously inhibited tumor growth in nude mice (P<0.05). In both cultured gastric cancer cells and the xenografts in nude mice, MRPL13 overexpression significantly decreased while MRPL13 knockdown enhanced the expressions of p53 and p21 (P<0.05). MRPL13 is highly expressed in gastric cancer and affects the long- term prognosis of the patients possibly by inhibiting p53 signaling to promote cancer cell proliferation and cell cycle progression.

Pivotal role of the ORAI3-STIM2 complex in the control of mitotic death and prostate cancer cell cycle progression

Prostate cancer (PCa) represents one of the most frequent diagnosed cancer in males worldwide. Due to routine screening tests and the efficiency of available treatments, PCa-related deaths have significantly decreased over the past decades. However, PCa remains a critical threat if detected at a late stage in which, cancer cells would have already detached from the primary tumor to spread and invade other parts of the body. Calcium (Ca2+) channels and their protein regulators are now considered as hallmarks of cancer and some of them have been well examined in PCa. Among these Ca2+ channels, isoform 3 of the ORAI channel family has been shown to regulate the proliferation of PCa cells via the Arachidonic Acid-mediated Ca2+ entry, requiring the involvement of STIM1 (Stromal Interaction Molecule 1). Still, no study has yet demonstrated a role of the “neglected” STIM2 isoform in PCa or if it may interact with ORAI3 to promote an oncogenic behavior. In this study, we demonstrate that ORAI3 and STIM2 are upregulated in human PCa tissues. In old KIMAP (Knock-In Mouse Prostate Adenocarcinoma) mice, ORAI3 and STIM2 mRNA levels were significantly higher than ORAI1 and STIM1. In vitro, we show that ORAI3-STIM2 interact under basal conditions in PC-3 cells. ORAI3 silencing increased Store Operated Ca2+ Entry (SOCE) and induced a significant increase of the cell population in G2/M phase of the cell cycle, consistent with the role of ORAI3 as a negative regulator of SOCE. Higher expression levels of CDK1-Y15/Cyclin B1 were detected and mitotic arrest-related death occurred after ORAI3 silencing, which resulted in activating Bax/Bcl-2-mediated apoptotic pathway and caspase-8 activation and cleavage. STIM2 and ORAI3 expression increased in M phase while STIM1 expression and SOCE amplitude significantly decreased. Taken together, ORAI3 -STIM2 complex allows a successful progression through mitosis of PCa cells by evading mitotic catastrophe.

Translation of paired box 6 (PAX6) mRNA is IRES-mediated and inhibited by cymarin in breast cancer cells.

Paired box 6 (PAX6) is a member of the PAX family and plays an essential role in cancer cell cycle progression, colony formation, proliferation and invasion. Its expression is upregulated in many cancers including breast cancer, but the process of PAX6 mRNA translation has rarely been studied. We found that PAX6 translation level increased in MCF-7 breast cancer cells treated with the chemotherapeutic drug adriamycin (ADM), which might be attributable to internal ribosome entry site (IRES)-mediated translation. By modifying a bicistronic luciferase plasmid that is widely used to examine IRES activity, we found that the 469-base 5'-UTR of PAX6 mRNA contains an IRES element and that core IRES activity is located between nucleotides 159 and 333. Moreover, PAX6 IRES activity was induced during ADM treatment, which may be the main reason for the elevated level of PAX6 protein. We also found that cymarin, a cardiac glycoside, acts as an inhibitor of PAX6 protein expression by impairing its IRES-mediated translation. Furthermore, MCF-7 cell proliferation was suppressed during treatment with cymarin. These results provide novel insights into the translation mechanism of PAX6 in breast cancer cells and suggest that cymarin is a promising candidate for the treatment of breast cancer via targeting the expression of PAX6.

Dysregulated Stem Cell Markers Musashi-1 and Musashi-2 are Associated with Therapy Resistance in Inflammatory Breast Cancer

While preliminary evidence points to pro-tumorigenic roles for the Musashi (MSI) RNA-binding proteins Musashi-1 (MSI1) and Musashi-2 (MSI2) in some breast cancer subtypes, no data exist for inflammatory breast cancer (IBC). MSI gene expression was quantified in IBC SUM149PT cells. We then used small interfering RNA-based MSI1 and MSI2 double knockdown (DKD) to understand gene expression and functional changes upon MSI depletion. We characterized cancer stem cell characteristics, cell apoptosis and cell cycle progression via flow cytometry, mammospheres via spheroid assays, migration and proliferation via digital holographic microscopy, and cell viability using BrdU assays. Chemoresistance was determined for paclitaxel and cisplatin with MTT assays and radioresistance was assessed with clonogenic analyses. In parallel, we supported our in vitro data by analyzing publicly available patient IBC gene expression datasets. MSI1 and MSI2 are upregulated in breast cancer generally and IBC specifically. MSI2 is more commonly expressed compared to MSI1. MSI DKD attenuated proliferation, cell cycle progression, migration, and cell viability while increasing apoptosis. Stem cell characteristics CD44(+)/CD24(-), TERT and Oct4 were associated with MSI expression in vivo and were decreased in vitro after MSI DKD as was ALDH expression and mammosphere formation. In vivo, chemoresistant tumors were characterized by MSI upregulation upon chemotherapy application. In vitro, MSI DKD was able to alleviate chemo- and radioresistance. The Musashi RNA binding proteins are dysregulated in IBC and associated with tumor proliferation, cancer stem cell phenotype, chemo- and radioresistance. MSI downregulation alleviates therapy resistance and attenuates tumor proliferation in vitro.

Regulatory miRNAs, circRNAs and lncRNAs in cell cycle progression of breast cancer.

Breast cancer is a complex and heterogeneous disease that poses a significant public health concern worldwide, and it remains a major challenge despite advances in treatment options. One of the main properties of cancer cells is the increased proliferative activity that has lost regulation. Dysregulation of various positive and negative modulators in the cell cycle has been identified as one of the driving factors of breast cancer. In recent years, non-coding RNAs have garnered much attention in the regulation of cell cycle progression, with microRNAs (miRNAs), circular RNAs (circRNAs), and long non-coding RNAs (lncRNAs) being of particular interest. MiRNAs are a class of highly conserved and regulatory small non-coding RNAs that play a crucial role in the modulation of various cellular and biological processes, including cell cycle regulation. CircRNAs are a novel form of non-coding RNAs that are highly stable and capable of modulating gene expression at posttranscriptional and transcriptional levels. LncRNAs have also attracted considerable attention because of their prominent roles in tumor development, including cell cycle progression. Emerging evidence suggests that miRNAs, circRNAs and lncRNAs play important roles in the regulation of cell cycle progression in breast cancer. Herein, we summarized the latest related literatures in breast cancer that emphasize the regulatory roles of miRNAs, circRNAs and lncRNAs in cell cycle progress of breast cancer. Further understanding of the precise roles and mechanisms of non-coding RNAs in breast cancer cell cycle regulation could lead to the development of new diagnostic and therapeutic strategies for breast cancer.

USP13 deubiquitinates and stabilizes cyclin D1 to promote gastric cancer cell cycle progression and cell proliferation

The reversible post-translational modifications of protein ubiquitination and deubiquitination play a crucial regulatory role in cellular homeostasis. Deubiquitinases (DUBs) are responsible for the removal of ubiquitin from the protein substrates. The dysregulation of the DUBs may give rise to the occurrence and development of tumors. In this study, we investigated the gastric cancer (GC) data from the TCGA and GEO databases and found that ubiquitin-specific protease USP13 was significantly up-regulated in GC samples. The higher expression of USP13 was associated with the worse prognosis and shorter overall survival (OS) of GC patients. Enforced expression of USP13 in GC cells promoted the cell cycle progression and cell proliferation in an enzymatically dependent manner. Conversely, suppression of USP13 led to GC cell cycle arrest in G1 phase and the inhibition of cell proliferation. Nude mouse experiments indicated that depletion of USP13 in GC cells dramatically suppressed tumor growth in vivo. Mechanistically, USP13 physically bound to the N-terminal domain of cyclin D1 and removed its K48- but not K63-linked polyubiquitination chain, thereby stabilizing and increasing cyclin D1. Furthermore, re-expression of cyclin D1 partially reversed the cell cycle arrest and cell proliferation inhibition induced by USP13 depletion in GC cells. Additionally, USP13 protein abundance was positively correlated with the protein level of cyclin D1 in human GC tissues. Taken together, our data demonstrate that USP13 deubiquitinates and stabilizes cyclin D1, thereby promoting cell cycle progression and cell proliferation in GC. These findings suggest that USP13 might be a promising therapeutic target for the treatment of GC.