RNA-binding Motif Protein 3 Expression Research Articles

RBM3 Inhibits the Cell Cycle of Cutaneous Squamous Cell Carcinoma through the PI3K/AKT Signaling Pathway.

RBM3 is a key RNA-binding protein that has been implicated in various cellular processes, including cell proliferation and cell cycle regulation. However, its role in cutaneous squamous cell carcinoma (cSCC) remains poorly understood. We aimed to investigate the expression levels of RNA-binding motif protein 3 (RBM3) in patients with cSCC and evaluate its effect on cell ability in cSCC and its underlying regulatory mechanisms. The expression of RBM3 in cSCC tissues and A431 cells was determined via immunohistochemistry and western blotting. Plenti-CMV-RBM3- Puro was used to overexpress RBM3. The effect of RBM3 on the proliferation ability of cSCC cells was evaluated using MTT and colony formation assay. Cell apoptosis and cell cycle were determined using flow cytometry, while the protein expressions of BAX, NF-κB, BCL2, CASPASE 3, CYCLIN B, CYCLIN E, CDK1, phosphorylated (P)-CDK1, CDK2, P-CDK2, ERK, P-ERK, P-AMPK, AKT, P-AKT, MDM2, and P53 were assessed using western blotting. RBM3 expression was significantly downregulated in cSCC tissues and A431 cells. RBM3 overexpression significantly inhibited the cell proliferation and colony formation ability of A431. Notably, RNA-seq results showed that the differentially expressed genes associated with RBM3 were primarily involved in the regulation of the cell cycle, oocyte meiosis, and P53 signaling pathway, as well as the modulation of the MAPK, AMPK, Hippo, mTOR, PI3K/AKT, Wnt, FoxO, and NF-κB signaling pathways. Additionally, our findings demonstrated that overexpression of RBM3 inhibited cell proliferation and induced cell cycle arrest of cSCC through modulation of the PI3K/AKT signaling pathway. This study provides novel insights into the suppressive roles of RBM3 in cell proliferation and the cell cycle in cSCC and highlights its therapeutic potential for cSCC.

Matrine inhibits cell proliferation, invasion, and stem cell formation in hepatocellular carcinoma by regulating the ELAVL1/RBM3‐mediated Wnt/β‐catenin signaling pathway

AbstractMatrine has been reported to exert anti‐tumor effects in various cancers, including hepatocellular carcinoma (HCC). Nevertheless, the anti‐tumor molecular mechanism of Martine in HCC is still not fully revealed. Cell proliferative ability, apoptosis, invasion, and sphere formation ability were detected using 3‐(4, 5‐dimethyl‐2‐thiazolyl)‐2, 5‐diphenyl‐2‐H‐tetrazolium bromide (MTT), 5‐ethynyl‐2′‐deoxyuridine (EdU), flow cytometry, transwell, and sphere formation assays. CyclinD1, MMP2, RNA‐binding motif protein 3 (RBM3), embryonic lethal abnormal visual‐like protein 1 (ELAVL1), Wnt3A, and β‐catenin protein levels were assessed using western blot. RBM3 and ELAVL1 expression was measured using real‐time quantitative polymerase chain reaction (RT‐qPCR). After being predicted using Starbase, the possible interaction between ELAVL1 and RBM3 was identified using Co‐Immunoprecipitation (IP) assays. A xenograft model was used to examine how Matrine affects HCC cell growth in vivo. Matrine hindered HCC cell proliferation, invasion, and sphere formation ability, and boosted apoptosis in vitro. ELAVL1 and RBM3 content was decreased in Matrine‐treated HCC cells in a concentration‐dependent manner and was increased in HCC tissues and cell lines. Moreover, ELAVL1 might bind with RBM3 to positively regulate the stability of RBM3 mRNA. Matrine modulated the Wnt/β‐catenin signaling pathway by ELAVL1/RBM3 axis. Matrine blocked tumor growth in xenograft modes in vivo. Matrine suppressed HCC cell progression partly by regulating the ELAVL1/RBM3, providing the possible therapeutic strategy for HCC treatment.

RBM3 is associated with acute lung injury in septic mice and patients via the NF-κB/NLRP3 pathway.

Sepsis refers to host response disorders caused by infection, leading to life-threatening organ dysfunction. RNA-binding motif protein 3 (RBM3) is an important cold-shock protein that is upregulated in response to mild hypothermia or hypoxia. In this study, we aimed to investigate whether RBM3 is involved in sepsis-associated acute lung injury (ALI). Intraperitoneal injection of LPS (10mg/kg) was performed in wild type (WT) and RBM3 knockout (KO, RBM3-/-) mice to establish an in vivo sepsis model. An NLRP3 inflammasome inhibitor, MCC950 (50mg/kg), was injected intraperitoneally 30min before LPS treatment. Serum, lung tissues, and BALF were collected 24h later for further analysis. In addition, we also collected serum from sepsis patients and healthy volunteers to detect their RBM3 expression. The results showed that the expression of RBM3 in the lung tissues of LPS-induced sepsis mice and the serum of patients with sepsis was significantly increased and positively correlated with disease severity. In addition, RBM3 knockout (KO) mice had a low survival rate, and RBM3 KO mice had more severe lung damage, inflammation, lung cell apoptosis, and oxidative stress than WT mice. LPS treatment significantly increased the levels of nucleotide binding and oligomerization domain-like receptor family 3 (NLRP3) inflammasomes and mononuclear cell nuclear factor-κB (NF-κB) in the lung tissues of RBM3 KO mice. However, these levels were only slightly elevated in WT mice. Interestingly, MCC950 improved LPS-induced acute lung injury in WT and RBM3 KO mice but inhibited the expression of NLRP3, caspase-1, and IL-1β. In conclusion, RBM3 was overexpressed in sepsis patients and LPS-induced mice. RBM3 gene deficiency aggravated sepsis-associated ALI through the NF-κB/NLRP3 pathway.

Mild hypothermia ameliorates hepatic ischemia reperfusion injury by inducing RBM3 expression

Liver ischemia reperfusion injury (IRI) is a serious complication of certain liver surgeries, and it is difficult to prevent. As a potential drug-free treatment, mild hypothermia has been shown to promote positive outcomes in patients with IRI. However, the protective mechanism remains unclear. We established in vivo and in vitro models of hepatic ischemia reperfusion (IR) and mild hypothermia pretreatment. Hepatocytes were transfected with RNA-binding motif protein 3 (RBM3) overexpression plasmids, and IR was performed. Cell, culture medium, blood and tissue samples were collected to assess hepatic injury, oxidative stress, apoptosis and changes in RBM3 expression in the liver. Upregulation of RBM3 expression by mild hypothermia reduced the aminotransferase release, liver tissue injury and mitochondrial injury induced by liver IR. Hepatic IR-induced p38 and c-Jun N-terminal kinase (JNK) signaling pathway activation, oxidative stress injury and apoptosis could be greatly reversed by mild hypothermia. Overexpression of RBM3 mimicked the hepatoprotective effect of mild hypothermia. Mild hypothermia protects the liver from ischemia reperfusion-induced p38 and JNK signaling pathway activation, oxidative stress injury and apoptosis through the upregulation of RBM3 expression.

RNA Binding Motif Protein 3 Promotes Cell Metastasis and Epithelial-Mesenchymal Transition Through STAT3 Signaling Pathway in Hepatocellular Carcinoma.

PurposeRNA binding motif protein 3 (RBM3) has been reported to be dysregulated in various cancers and associated with tumor aggressiveness. Epithelial–mesenchymal transition (EMT) is an important biological process by which tumor cells acquire metastatic abilities. This study aimed to explore the regulatory and molecular mechanisms of RBM3 in EMT process.MethodsWestern blotting, IHC, and qRT-PCR were performed to evaluate the expression of target genes. Transwell assay was used to investigate the migration and invasion. RNA immunoprecipitation and luciferase reporter assay were performed to explore the correlation of RBM3 with STAT3 or microRNA-383. Animal HCC models were used to explore the role of RBM3 in metastasis in vivo.ResultsRBM3 was highly expressed in HCC tissues compared to healthy tissues, and its level was negatively correlated with the prognosis of HCC patients. RBM3 overexpression accelerated migration and invasion, promoted EMT process, and activated STAT3 signaling. EMT induced by RBM3 was not only attenuated by inhibiting pSTAT3 via S3I-201 but also abolished by suppressing STAT3 expression via siRNAs. Mechanistically, RBM3 increased STAT3 expression by stabilizing STAT3 mRNA via binding to its mRNA. As an upstream target of RBM3, microRNA-383 inhibited RBM3 expression by binding to its 3ʹUTR and resulted in the inhibition of the EMT process. Inhibition of RBM3 in HCC animal models prolonged survival and ameliorated malignant phenotypes in mice.ConclusionOur findings support that RBM3 promotes HCC metastasis by activating STAT3 signaling.

Pre-clinical and clinical studies on the role of RBM3 in muscle-invasive bladder cancer: longitudinal expression, transcriptome-level effects and modulation of chemosensitivity

BackgroundThe response to neoadjuvant cisplatin-based chemotherapy (NAC) in muscle-invasive bladder cancer (MIBC) is impaired in up to 50% of patients due to chemoresistance, with no predictive biomarkers in clinical use. The proto-oncogene RNA-binding motif protein 3 (RBM3) has emerged as a putative modulator of chemotherapy response in several solid tumours but has a hitherto unrecognized role in MIBC.MethodsRBM3 protein expression level in tumour cells was assessed via immunohistochemistry in paired transurethral resection of the bladder (TURB) specimens, cystectomy specimens and lymph node metastases from a consecutive cohort of 145 patients, 65 of whom were treated with NAC. Kaplan-Meier and Cox regression analyses were applied to estimate the impact of RBM3 expression on time to recurrence (TTR), cancer-specific survival (CSS), and overall survival (OS) in strata according to NAC treatment. The effect of siRNA-mediated silencing of RBM3 on chemosensitivity was examined in RT4 and T24 human bladder carcinoma cells in vitro. Cellular functions of RBM3 were assessed using RNA-sequencing and gene ontology analysis, followed by investigation of cell cycle distribution using flow cytometry.ResultsRBM3 protein expression was significantly higher in TURB compared to cystectomy specimens but showed consistency between primary tumours and lymph node metastases. Patients with high-tumour specific RBM3 expression treated with NAC had a significantly reduced risk of recurrence and a prolonged CSS and OS compared to NAC-untreated patients. In high-grade T24 carcinoma cells, which expressed higher RBM3 mRNA levels compared to RT4 cells, RBM3 silencing conferred a decreased sensitivity to cisplatin and gemcitabine. Transcriptomic analysis revealed potential involvement of RBM3 in facilitating cell cycle progression, in particular G1/S-phase transition, and initiation of DNA replication. Furthermore, siRBM3-transfected T24 cells displayed an accumulation of cells residing in the G1-phase as well as altered levels of recognised regulators of G1-phase progression, including Cyclin D1/CDK4 and CDK2.ConclusionsThe presented data highlight the potential value of RBM3 as a predictive biomarker of chemotherapy response in MIBC, which could, if prospectively validated, improve treatment stratification of patients with this aggressive disease.

Mild therapeutic hypothermia improves neurological outcomes in a rat model of cardiac arrest

Cardiac arrest (CA) is the leading cause of death in humans. Research has shown that mild therapeutic hypothermia (MTH) can reduce neurological sequelae and mortality after CA. Nevertheless, the mechanism remains unclear. This study aimed to determine whether MTH promotes neurogenesis, attenuates neuronal damage, and inhibits apoptosis of neurons in rats after CA. Sprague–Dawley rats were divided into the normothermia and mild hypothermia groups. The rats in the normothermia and hypothermia groups were exposed to 2 h of normothermia (36–37℃) and hypothermia (32–33℃), respectively, immediately after resuscitation from 5 min of asphyxial CA. Corresponding control groups not subjected to CA were included. On days 1–6, 5-bromodeoxyuridine (BrdU) 100 mg/kg/day was administered intraperitoneally. The animals were euthanized 1 week after CA. Compared with the normothermia group, the hypothermia group showed a significant increase in the number of doublecortin (DCX) immune-positive cells in the subgranular zone of the hippocampus 1 week after CA. Neurogenesis was assessed using double immunofluorescent labeling of BrdU with neuronal-specific nuclear protein (NeuN)/DCX. There was no marked change in the number of newborn mature (BrdU+-NeuN+) neurons, though there was a significant increase in the number of newborn immature (BrdU+-DCX+) neurons in the hypothermia than in the normothermia group 1 week after CA. Neuronal injury and apoptosis in the CA1 region of the hippocampus, assessed using NeuN immunofluorescence and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays, were significantly reduced in the hypothermia group 1 week after CA. Moreover, mild hypothermia increased the expression of cold-shock protein RNA-binding motif protein 3 (RBM3) in the early stage (24 h/48 h) after CA. These results suggested that mild hypothermia promotes generation of neuronal cells, reduces neuronal injury, and inhibits apoptosis of neurons, which may be related to RBM3 expression.

Clinical significance of RBM3 expression in surgically treated colorectal lung metastases and paired primary tumors.

The lungs are the second most common site of metastases in colorectal cancer (CRC). The aim of this study was to investigate prognostic factors, including RNA-binding motif protein 3 (RBM3) expression, in patients with CRC treated with pulmonary metastasectomy (PM). The cohort included all patients treated with PM at Skåne University Hospital, Lund, Sweden, from 2000 to 2014. Clinicopathological, treatment, and survival data were collected. Immunohistochemical staining of RBM3 was evaluated on tissue microarrays with samples from all lung metastases and a subset of paired primary tumors. Kaplan-Meier analysis and Cox proportional hazards modeling were applied to examine the associations of investigative factors with overall survival (OS) and recurrence-free survival. In total, 216 patients with a primary tumor in the rectum (57%), left colon (34%), or right colon (9%) underwent PM. The 5-year OS rate was 56%. Age > 60 years, more than one metastasis, size of metastasis > 3 cm, disease-free interval < 24 months, low RBM3 score in the lung metastasis, and no adjuvant chemotherapy following PM were prognostic factors for shorter OS. Several prognostic factors, including RBM3 expression, may be of aid in selecting CRC patients with lung metastases for PM as well as adjuvant therapy.

The Expression of the Cold Shock Protein RNA Binding Motif Protein 3 is Transcriptionally Responsive to Organ Temperature in Mice.

Mild hypothermia, i.e. maintenance of organ temperature by up to 8°C lower than body temperature, is a critical strategy for exerting some functions of the cells and organs normally, and is an useful therapy for recovering properly from some diseases, including myocardial infarction, cardiac arrest, brain injury, and ischemic stroke. Nevertheless, there were no focusses so far on organ temperature and potential responses of gene expression to organ temperature in organs of homeothermic animals that survive under normal conditions. The present study aimed to assess organ temperature in homeothermic animals and evaluate the effect of their organ temperature on the expression of the cold shock protein RNA binding motif protein 3 (RBM3), and to gain insights into the organ temperature-mediated regulation of RBM3 gene transcription via Nuclear factor β-light-chain-enhancer of activated B cells (NF-κB) p65, which had been identified as a transcription factor that is activated by undergoing the Ser276 phosphorylation and promotes the RBM3 gene expression during mild hypothermia. We measured the temperature of several organs, where RBM3 expression was examined, in female and male mice. Next, in male mice, we tested NF-κB p65 expression and its Ser276 phosphorylation in organs that have their lower temperature than body temperature and compared them with those in organs that have their temperature near body temperature. Organ temperature was around 32°C in the brain and reproductive organs, which is lower than the body temperature, and around 37°C in the heart, liver, and kidney, which is comparable to the body temperature. The expression of RBM3 was detected greatly in the brain and reproductive organs with their organ temperature of around 32°C, and poorly in the heart, liver, and kidney with their organ temperature of around 37°C. In accordance with the changes in the RBM3 expression, the NF-κB p65 Ser276 phosphorylation was detected more greatly in the testis and brain with their organ temperature of around 32°C, than in the heart, liver, and kidney with their organ temperature of around 37°C, although the NF-κB p65 expression was unchanged among all the organs tested. Our data suggested that organ temperature lower than body temperature causes the expression of RBM3 in the brain and reproductive organs of mice, and that lower organ temperature causes the NF-κB p65 activation through the Ser276 phosphorylation, resulting in an increase in the RBM3 gene transcription, in the brain and reproductive organs of mice. The study may present the possibility that organ temperature-induced alterations in gene expression are organ specific in homeotherms and the possibility that organ temperature-induced alterations in gene expression are transcriptionally regulated in some organs of homeotherms.

Role of RBM3 in the regulation of cell proliferation in hepatocellular carcinoma

RNA binding motif protein 3 (RBM3) has been shown to be upregulated in several types of human tumors. Using tissue microarrays and immunohistochemistry, we showed here that both nuclear and cytoplasmic RBM3 expression levels were higher in hepatocellular carcinoma (HCC) tissues than in adjacent non-tumorous tissues. High nuclear RBM3 was found to be correlated with larger tumor size (P = 0.030), high serum AFP levels (P = 0.011), and advanced Edmonson grading (P = 0.006). Cytoplasmic RBM3 was associated with advanced Edmonson grading (P = 0.003). Kaplan-Meier survival analysis revealed that, although not statistically significant, there was a trend toward shortened overall survival in the subset of HCC patients with high RBM3 expression (both nuclear and cytoplasmic). In addition, we found that RBM3 could promote YAP1 expression in HCC cells. Moreover, we found that YAP1 played an essential part in RBM3-induced proliferation of HCC cells. Furthermore, we demonstrated that Verteporfin, a YAP1 inhibitor, could repress RBM3-induced proliferation of HCC cells. Our findings provide a new experimental basis for further understanding of the possible role of RBM3-YAP1 in the regulation of HCC proliferation.

The overexpression of RBM3 alleviates TBI-induced behaviour impairment and AD-like tauopathy in mice.

The therapeutic hypothermia is an effective tool for TBI‐associated brain impairment, but its side effects limit in clinical routine use. Hypothermia up‐regulates RNA‐binding motif protein 3 (RBM3), which is verified to protect synaptic plasticity. Here, we found that cognitive and LTP deficits, loss of spines, AD‐like tau pathologies are displayed one month after TBI in mice. In contrast, the deficits of LTP and cognitive, loss of spines and tau abnormal phosphorylation at several sites are obviously reversed in TBI mice combined with hypothermia pre‐treatment (HT). But, the neuroprotective role of HT disappears in TBI mouse models under condition of blocking RBM3 expression with RBM3 shRNA. In other hand, overexpressing RBM3 by AAV‐RBM3 plasmid can mimic HT‐like neuroprotection against TBI‐induced chronic brain injuries, such as improving LTP and cognitive, loss of spines and tau hyperphosphorylation in TBI mouse models. Taken together, hypothermia pre‐treatment reverses TBI‐induced chronic AD‐like pathology and behaviour deficits in RBM3 expression dependent manner, RBM3 may be a potential target for neurodegeneration diseases including Alzheimer disease.

The prognostic and clinicopathological significance of RBM3 in the survival of patients with tumor: A Prisma-compliant meta-analysis.

Background:RNA-binding motif protein 3 (RBM3) plays an important role in carcinogenesis and tumor progression. However, the prognostic role of RBM3 in human carcinomas remains controversial. Therefore, we took a meta-analysis to research the association between the overall survival of patients with cancer and the expression of RBM3.Methods:Systematic literature research identified 17 potentially eligible studies comprising 4976 patients in ten different cancer types. Two researchers independently screened the content and quality of studies and extracted data. Correlations of RBM3 expression and survival were analyzed and the hazard ratios (HRs) with 95% confidence intervals (95% CIs) were calculated.Results:In the pooled analysis, overexpression of RBM3 was related to improved overall survival (OS), recurrence-free survival (RFS), and disease-free survival (DFS) in patients with cancer having a pooled HR of 0.61 (HR = 0.61; 95% CI: 0.47–0.69), 0.57 (HR = 0.60; 95% CI: 0.50–0.71) and 0.54 (HR 0.54; 95% CI: 0.38–0.78). Besides, subgroup analysis proved that overexpression of RBM3 was related to improved OS in colorectal cancer (HR = 0.61, 95% CI: 0.43–0.86), melanoma (HR = 0.32, 95% CI: 0.20–0.52), and gastric cancer (HR = 0.51, 95% CI: 0.35–0.73). However, subgroup analysis according to tumor type revealed that overexpression of RBM3 was not related to better OS in breast carcinoma (HR = 0.52, 95% CI: 0.17–0.61).Conclusions:Our results indicated that RBM3 overexpression was significantly predictive of better prognosis in various human cancers. For certain tumors, overexpression RBM3 might be a marker of improved survival in humans with cancer, except for breast cancer.

Prevalence and clinical significance of RBM3 immunostaining in non-small cell lung cancers.

Aberrant expression of RNA-binding motif protein 3 (RBM3) has been suggested as a prognostic biomarker in several malignancies. This study was performed to analyse the prevalence and clinical significance of RBM3 immunostaining in non-small cell lung cancers (NSCLCs). Therefore, we took advantage of our tissue microarray (TMA) containing more than 600 NSCLC specimens. While nuclear RBM3 staining was always high in normal lung tissue, high RBM3 staining was only seen in 77.1% of 467 interpretable non-metastatic NSCLCs. Reduced RBM3 staining was significantly associated with advanced pathological tumor stage (pT) in NSCLCs (p = 0.0031). Subset analysis revealed that the association between reduced RBM3 staining and advanced pT stage was largely driven by the histological subgroup of lung adenocarcinoma (LUACs) (p = 0.0036). In addition, reduced RBM3 expression predicted shortened survival in LUAC patients (p = 0.0225). In summary, our study shows that loss of RBM3 expression predicts worse clinical outcome in LUAC patients.

Morphoregulatory functions of the RNA-binding motif protein 3 in cell spreading, polarity and migration

RNA-binding proteins are emerging as key regulators of transitions in cell morphology. The RNA-binding motif protein 3 (RBM3) is a cold-inducible RNA-binding protein with broadly relevant roles in cellular protection, and putative functions in cancer and development. Several findings suggest that RBM3 has morphoregulatory functions germane to its roles in these contexts. For example, RBM3 helps maintain the morphological integrity of cell protrusions during cell stress and disease. Moreover, it is highly expressed in migrating neurons of the developing brain and in cancer invadopodia, suggesting roles in migration. We here show that RBM3 regulates cell polarity, spreading and migration. RBM3 was present in spreading initiation centers, filopodia and blebs that formed during cell spreading in cell lines and primary myoblasts. Reducing RBM3 triggered exaggerated spreading, increased RhoA expression, and a loss of polarity that was rescued by Rho kinase inhibition and overexpression of CRMP2. High RBM3 expression enhanced the motility of cells migrating by a mesenchymal mode involving extension of long protrusions, whereas RBM3 knockdown slowed migration, greatly reducing the ability of cells to extend protrusions and impairing multiple processes that require directional migration. These data establish novel functions of RBM3 of potential significance to tissue repair, metastasis and development.

A translational effort to identify prognostic and predictive biomarkers in pancreatic cancer among RBM3-regulated genes.

305 Background: Pancreatic cancer has a dismal prognosis and clinical protocols are still lacking predictive biomarkers. RNA-binding motif protein 3 (RBM3) has emerged as a promising biomarker in several solid cancers, including pancreatic cancer. High RBM3 expression in human tumors has been associated with good response to chemotherapy, as well as to confer increased chemosensitivity in vitro. The aim of this study was to identify RBM3-regulated genes in pancreatic cells in vitro, and further interrogate their potential utility as prognostic and predictive biomarkers in a translational setting. Methods: Next generation RNA-sequencing was applied to compare gene expression between MIAPaCa-2 cells with siRNA-downregulated RBM3 and control cells. Single genes with the strongest association to RBM3 were further selected by gene set enrichment analysis, and their prognostic value in pancreatic cancer was examined in The Cancer Genome Atlas (TCGA). The most promising biomarker candidates with well-validated antibodies were then analyzed by immunohistochemistry in tissue microarrays with tumors from a consecutive, retrospective cohort of 175 patients with periampullary and pancreatic adenocarcinoma. Results: MIAPaCa-2 cells with downregulated RBM3 displayed 21 differentially expressed genes (p &lt; 0.01). One of the top downregulated genes was PDS cohesion associated factor A (PDS5A) encoding a protein involved in sister chromatid cohesion. PDS5A protein expression was reduced in siRBM3-treated MIAPaCa-2 cells compared to control cells. High PDS5A mRNA expression was significantly associated with a reduced survival in pancreatic cancer in the TCGA (n = 176, p = 0.026). High PDS5A protein expression in the separate cohort was significantly associated with a poor prognosis but predictive of improved response to adjuvant chemotherapy in KRAS-mutated, but not wild-type, pancreatobiliary-type tumors (p for interaction = 0.043). Conclusions: Here, we provide the first report of the expression of PDS5A in pancreatic and periampullary cancer, suggesting its potential utility as a prognostic and predictive biomarker. Further studies to unravel the underlying mechanisms are encouraged.

High RNA-binding Motif Protein 3 Expression Is Associated with Improved Clinical Outcomes in Invasive Breast Cancer.

PurposeExpression of RNA-binding motif protein 3 (RBM3) is induced by hypoxia and hypothermia. Recently, high expression of RBM3 was reported to be associated with a good prognosis in colon cancer, prostate cancer, ovarian cancer, and malignant melanoma. Studies on RBM3 in invasive breast carcinoma (IBC), however, are limited.MethodsRBM3 expression was examined using a tissue microarray from 361 patients with IBC. Immunohistochemistry was performed for estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 to compare the expression of these markers. For scoring of RBM3 expression, NF (nuclear staining fraction)×NI (nuclear staining intensity) was used. The RBM3 expression score was considered indicative of either low (≤4) or high (>4) expression. Western blot analysis was performed on breast cancer cell lines to evaluate RBM3 expression.ResultsOf the total 361 samples, 240 (66.5%) exhibited high RBM3 expression. High RBM3 expression was significantly associated with positivity for ER (p<0.001), PR (p<0.001), T stage (p<0.001), histologic grade (p<0.001), and % Ki-67 staining (p=0.004). Multivariate analysis revealed that high RBM3 expression was closely associated with prolonged disease-free survival (DFS) (p<0.001) and overall survival (OS) (p<0.001). Western blot analysis revealed reduced RBM3 expression in HCC1954 (HER2-enriched) and BT-20 (basal-like) cells with an aggressive phenotype.ConclusionHigh nuclear RBM3 expression is strongly associated with a prolonged DFS and OS. Furthermore, RBM3 expression is closely associated with good prognostic markers such as ER and PR in IBC. High nuclear RBM3 expression is, therefore, a critical biomarker of favorable clinical outcomes in IBC.

High RNA-Binding Motif Protein 3 (RBM3) Expression is Independently Associated with Prolonged Overall Survival in Intestinal-Type Gastric Cancer

BackgroundHigh expression of the RNA-binding motif protein 3 (RBM3) has previously been described as a favorable clinicopathological factor in several cancers, including ovarian cancer, colorectal cancer, prostate cancer, and breast cancer. The aim of this study was to examine the prognostic implications of RBM3 expression in gastric cancer.Material/MethodsImmunohistochemical analysis of RBM3 expression from 123 patients showed that upregulated RBM3 was mainly found in intestinal-type (n=78, case=59) cancer compared to diffuse-type (n=15, case=8) and mixed-type (n=30, case=17). There were no significant differences in RBM3 expression in subgroups of clinicopathological parameters. RBM3 expression was strongly associated with p53 but not with Ki-67. Cox univariate analysis revealed that high RBM3 expression was closely associated with prolonged overall survival time (HR 0.504, 95% CI: 0.300–0.845, P=0.009). Multivariate analysis remained supporting these associations when adjusted for age, sex, tumor size, differentiation grade, TNM stage, lymphatic invasion, and Ki-67 and p53 expression (HR 0.541, 95% CI: 0.308–0.952, P=0.033), where Lauren grade was not included. Lauren grade was the only factor with independent prognostic significance in a model adjusted for all factors. These results were confirmed by Kaplan-Meier analysis.ResultsTherefore, together with the upregulated RBM3 expression observed in intestinal-type of Lauren grade, we suggest that upregulation of RBM3 is partially responsible for the favorable overall survival in cases with intestinal Lauren grade, which is demonstrated by the box diagram and Kaplan-Meier analysis. Our results showed that high RBM3 expression in gastric cancer is mainly found in intestinal-type of Lauren grade and is associated with longer overall survival time.ConclusionWe found that RBM3 is a potential biomarker of good prognosis and deserves further validation.

Translational study reveals a two-faced role of RBM3 in pancreatic cancer and suggests its potential value as a biomarker for improved patient stratification.

Periampullary adenocarcinoma, including pancreatic cancer, is a heterogeneous group of tumors with dismal prognosis, partially due to lack of reliable targetable and predictive biomarkers. RNA-binding motif protein 3 (RBM3) has previously been shown to be an independent prognostic and predictive biomarker in several types of cancer. Herein, we examined the prognostic value of RBM3 in periampullary adenocarcinoma, as well as the effects following RBM3 suppression in pancreatic cancer cells in vitro. RBM3 mRNA levels were examined in 176 pancreatic cancer patients from The Cancer Genome Atlas. Immunohistochemical expression of RBM3 was analyzed in tissue microarrays with primary tumors and paired lymph node metastases from 175 consecutive patients with resected periampullary adenocarcinoma. Pancreatic cancer cells were transfected with anti-RBM3 siRNA in vitro and the influence on cell viability following chemotherapy, transwell migration and invasion was assessed. The results demonstrated that high mRNA-levels of RBM3 were significantly associated with a reduced overall survival (p = 0.026). RBM3 protein expression was significantly higher in lymph node metastases than in primary tumors (p = 0.005). High RBM3 protein expression was an independent predictive factor for the effect of adjuvant chemotherapy and an independent negative prognostic factor in untreated patients (p for interaction = 0.003). After siRNA suppression of RBM3 in vitro, pancreatic cancer cells displayed reduced migration and invasion compared to control, as well as a significantly increased resistance to chemotherapy. In conclusion, the strong indication of a positive response predictive effect of RBM3 expression in pancreatic cancer may be highly relevant in the clinical setting and merits further validation.

High RBM3 expression is associated with an improved survival and oxaliplatin response in patients with metastatic colorectal cancer.

BackgroundHigh expression of the RNA-binding motif protein 3 (RBM3) has been shown to correlate, with prolonged survival in several malignant diseases and with the benefit of platinum-based chemotherapy in ovarian cancer. The aim of this study was to evaluate RBM3 in metastatic colorectal cancer (mCRC) as a prognostic factor for overall survival and in relation to benefit of first-line chemotherapy.MethodsImmunohistochemical staining was conducted and evaluated in tumours from 455 mCRC patients. Kaplan-Meier analysis and Cox regression proportional hazards models were used to access the impact of RBM3 expression on overall survival (OS) and progression-free survival (PFS).ResultsHigh RBM3 expression, both nuclear and cytoplasmic, was an independent prognostic factor for prolonged OS (hazard ratio [HR] 0.67, 95% confidence interval [CI] 0.50–0.90 and HR 0.66, 95% CI 0.48–0.91, respectively). PFS was significantly longer in patients with high RBM3 expression who had received first-line oxaliplatin based treatment, compared to those who had received irinotecan based treatment, both regarding nuclear and cytoplasmic expression (p-value 0.020 and 0.022 respectively).ConclusionHigh RBM3 expression is an independent predictor of prolonged survival in mCRC patients, in particular in patients treated with first-line oxaliplatin based chemotherapy.

Stress Response Protein RBM3 Promotes the Development of Colitis-associated Cancer.

Colitis-associated cancer (CAC) is caused by chronic intestinal inflammation and often results from refractory inflammatory bowel disease (IBD). Stress response proteins Cirp and HSPA4 are involved in the refractory clinical course and development of CAC. RNA-binding motif protein 3 (RBM3) is induced in response to various stresses and is upregulated in several cancers. However, the role of RBM3 in CAC is unclear. We assessed RBM3 expression and function in 263 human intestinal mucosa samples from patients with IBD and in Rbm3-deficient (Rbm3) mice. Expression of RBM3 was correlated with the expression of stress response proteins Cirp, HSPA4, and HSP27 in the colonic mucosa of patients with IBD. Significant correlation was observed between the expression of RBM3 and that of Bcl-xL or stem cell markers. RBM3 expression increased and significantly correlated with R-spondin expression in the colonic mucosa of patients with refractory IBD, a condition associated with increased cancer risk, and RBM3 was overexpressed in human CACs. In the murine CAC model, Rbm3 deficiency decreased R-spondin and Bcl-xL expression and increased apoptotic cell number in the colonic mucosa, leading to reduced tumor multiplicity. Transplantation of wild-type and Rbm3 bone marrow did not alter tumor burden, indicating the importance of RBM3 in epithelial cells. Our findings indicated that RBM3 was required for efficient inflammatory carcinogenesis in the murine CAC model and suggested that RBM3 could be a predictive biomarker of CAC risk and a new therapeutic target for cancer prevention in patients with IBD.