Tissue expression of retinoic acid receptor alpha and CRABP2 in metastatic nephroblastomas

Inter-Ethnic Variations in the Clinical, Pathological, and Molecular Characteristics of Wilms Tumor

Wilms tumor is the commonest primary renal malignancy in children and demonstrates substantial inter-ethnic variation in clinical, pathological, and molecular characteristics. Wilms tumor occurs at a lower incidence and at a younger age in Asians compared to Caucasians and Africans. Asians also present at an earlier stage of disease, with a higher incidence of favorable histology tumors and a lower incidence of perilobar nephrogenic rests compared to Caucasians, while African children present with more advanced disease. Studies have implicated population differences in the incidence of WT1 mutations, loss of imprinting of the IGF2 locus, and loss of heterozygosity of 1p/16q, or 1q gain as possible bases for epidemiological differences in the disease profile of Wilms tumors in various ethnic groups. Yet, evidence to support these associations is confounded by differences in treatment protocols and inequalities in the availability of treatment resources and remains limited by the quality of population-based data, especially in resource-limited settings.

Prognostic role of CRABP2 in lung cancer: a meta-analysis

BACKGROUND

The prognostic value of cellular retinoic acid-binding protein 2 (CRABP2), in lung cancer patients remains to be uncertained. Therefore, our research attempted to assess the relationship between CRABP2 and survival analysis in lung cancer patients through meta-analysis.

METHOD

Related literature retrieved from Cochrane Library, Ovid, Embase, PubMed, the CNKI, and the Web of Science. The latest update of the search was May 1, 2023. The outcome indicators included as effective measures in the study were hazard ratio (HR), and 95% confidence interval (CI). The Stata 12.0 software was used to analyze the data.

RESULTS

A total of4 studies were finally enrolled in our meta-analysis. The increased plasma level of CRABP2 predicted poor OS in lung cancer patient with a combined HR of 1.14 (95% CI: 1.00-1.30), and were not associated with poor PFS with combined HR: 1.15% CI: 0.63-2.09) in lung cancer patients.

CONCLUSIONS

Our meta-analysis found the increased plasma level of CRABP2 was associated with poor OS independently in NSCLC patients. The plasma CRABP2 level may be an indicator of biological aggressiveness of the tumor. Our research was promising regarding the feasibility and utility of plasma CRABP2 as a novel prognostic biomarker in NSCLC, and the findings warrant further investigation.

CRABP2 reduces the sensitivity of Olaparib in ovarian cancer by downregulating Caspase-8 and decreasing the production of reactive oxygen species

Poly (adenosine diphosphate-ribose) polymerase (PARP) inhibitors, such as Olaparib, have been pivotal in treating BRCA-deficient ovarian cancer. However, their efficacy is limited in over 40% of BRCA-deficient patients, with acquired resistance posing new clinical challenges. To address this, we employed bioinformatics methods to identify key genes impacting Olaparib sensitivity in ovarian cancer. Through comprehensive analysis of public databases including GEO, CPTAC, Kaplan Meier Plotter, and CCLE, we identified CRABP2 as significantly upregulated at both mRNA and protein levels in ovarian cancer, correlating with poor prognosis and decreased Olaparib sensitivity. Using colony formation and CCK-8 assays, we confirmed that CRABP2 knockdown in OVCAR3 and TOV112D cells enhanced sensitivity to Olaparib. Additionally, 4D label-free quantitative proteomics analysis, GSEA, and GO/KEGG analysis revealed CRABP2's involvement in regulating oxidation signals. Flow cytometry, colony formation assays, and western blotting demonstrated that CRABP2 knockdown promoted ROS production by activating Caspase-8, thereby augmenting Olaparib sensitivity and inhibiting ovarian cancer cell proliferation. Moreover, in xenograft models, CRABP2 knockdown significantly suppressed tumorigenesis and enhanced Olaparib sensitivity, with the effect being reversed upon Caspase-8 knockdown. These findings suggest that CRABP2 may modulate Olaparib sensitivity in ovarian cancer through the Caspase-8/ROS axis, highlighting its potential as a target for Olaparib sensitization.

CRABP2 regulates infiltration of cancer-associated fibroblasts and immune response in melanoma

Finding biomarkers for immunotherapy is an urgent issue in cancer treatment. Cellular retinoic acid-binding protein 2 (CRABP2) is a controversial factor in the occurrence and development of human tumors. However, there is limited research on the relationship between CRABP2 and immunotherapy response. This study found that negative correlations of CRABP2 and immune checkpoint markers (PD-1, PD-L1, and CTLA-4) were observed in breast invasive carcinoma (BRCA), skin cutaneous melanoma (SKCM), stomach adenocarcinoma (STAD) and testicular germ cell tumors (TGCT). In particular, in SKCM patients who were treated with PD-1 inhibitors, high levels of CRABP2 predicted poor prognosis. Additionally, CRABP2 expression was elevated in cancer-associated fibroblasts (CAFs) at the single-cell level. The expression of CRABP2 was positively correlated with markers of CAFs, such as MFAP5, PDPN, ITGA11, PDGFRα/β and THY1 in SKCM. To validate the tumor-promoting effect of CRABP2 in vivo, SKCM xenograft mice models with CRABP2 overexpression have been constructed. These models showed an increase in tumor weight and volume. Enrichment analysis indicated that CRABP2 may be involved in immune-related pathways of SKCM, such as extracellular matrix (ECM) receptor interaction and epithelial-mesenchymal transition (EMT). The study suggests that CRABP2 may regulate immunotherapy in SKCM patients by influencing infiltration of CAFs. In conclusion, this study provides new insights into the role of CRABP2 in immunotherapy response. The findings suggest that CRABP2 may be a promising biomarker for PD-1 inhibitors in SKCM patients. Further research is needed to confirm these findings and to explore the clinical implications of CRABP2 in immunotherapy.

Cancer invasion and metastasis: Insights from murine pubertal mammary gland morphogenesis

Cancer invasion and metastasis accounts for the majority of cancer related mortality. A better understanding of the players that drive the aberrant invasion and migration of tumors cells will provide critical targets to inhibit metastasis. Postnatal pubertal mammary gland morphogenesis is characterized by highly proliferative, invasive, and migratory normal epithelial cells. Identifying the molecular regulators of pubertal gland development is a promising strategy since tumorigenesis and metastasis is postulated to be a consequence of aberrant reactivation of developmental stages. In this review, we summarize the pubertal morphogenesis regulators that are involved in cancer metastasis and revisit pubertal mammary gland transcriptome profiling to uncover both known and unknown metastasis genes. Our updated list of pubertal morphogenesis regulators shows that most are implicated in invasion and metastasis. This review highlights molecular linkages between development and metastasis and provides a guide for exploring novel metastatic drivers.

The prognostic gene CRABP2 affects drug sensitivity by regulating docetaxel-induced apoptosis in breast invasive carcinoma: A pan-cancer analysis

Cellular retinoic acid-binding protein 2 (CRABP2), a specific transporter of retinoic acid, has been shown to have an important biological role in human cancers. However, due to the substantial variability among different tumors, the role of CRABP2 remains uncertain and has not yet been subjected to systematic analysis. Utilizing The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Clinical Proteomic Tumor Analysis Consortium (CPTAC), Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis 2 (GEPIA2), Kaplan-Meier Plotter, Biomarker Exploration of Solid Tumors (BEST), Cancer Cell Line Encyclopedia (CCLE), Receiver Operating Characteristic plotter (ROC plotter), and other online public tools, expression levels of CRABP2 in breast invasive carcinoma (BRCA), lung adenocarcinoma (LUAD), and ovarian serous cystadenocarcinoma (OV) were found to be significantly greater than those in adjacent normal tissues, suggesting a correlation to poor prognosis. Among the three, CRABP2 expression in BRCA was most closely associated with clinical prognosis. In a study of docetaxel-treated BRCA patients, CRABP2 expression was significantly higher in the drug-resistant group. Colony formation and flow cytometry analysis were used to further investigate the relationship between CRABP2 and docetaxel sensitivity in BRCA cells MDA-MB-231and BT549. The knockdown of CRABP2 expression significantly reduced cell growth and increased sensitivity to the chemotherapeutic agent docetaxel in BRCA cells. Furthermore, CRABP2 knockdown augmented docetaxel-induced apoptosis. Molecular docking using SwissDock tool revealed that CRABP2 had a greater binding affinity to docetaxel than docetaxel-targeted proteins. This research provides an insight into the expression and prognostic potential of CRABP2 in cancers and suggests that CRABP2 may control docetaxel sensitivity in BRCA cells through apoptosis, warranting further investigation.

CRABP2 accelerates epithelial mesenchymal transition in serous ovarian cancer cells by promoting TRIM16 methylation via upregulating EZH2 expression

Recently, it was covered that cellular retinoic acid-binding protein 2 (CRABP2) is upregulated in ovarian cancer and participates in tumor progression, however, the specific mechanism remains to be explored. The pcDNA-CRABP2 or si-CRABP2 was transfected into SKOV3 and OVCAR3 ovarian cancer cells, respectively, and we observed that overexpression of CRABP2 inhibited cell apoptosis, promoted cell invasion and expression of epithelial mesenchymal transition (EMT) marker proteins, and transfection of si-CRABP2 had the opposite effect. Furthermore, we predicted that EZH2 interacted with CRABP2, and overexpression of CRABP2 promoted EZH2 expression, knockdown of CRABP2 inhibited EZH2 expression, and co-immunoprecipitation assay confirmed their binding relationship. The SKOV3 and OVCAR3 cells were then incubated with pcDNA-CRABP2 alone together with si-EZH2, and we found that si-EZH2 reversed the effect of pcDNA-CRABP2 on promotion of EZH2 expression, cell invasion and EMT maker protein levels. Next, we found that EZH2 could bind to DNMT1, and overexpression of EZH2 inhibited TRIM16 expression and knockdown of EZH2 promoted TRIM16 expression. Moreover, the promoter of TRIM16 contains the CpG island, and ChIP assay observed enriched DNMT1 on the promoter of TRIM16, and overexpression of EZH2 increased the promoter methylation level of TRIM16 and knockdown of EZH2 suppressed the methylation. The SKOV3 cells were incubated with si-EZH2 alone or combined with si-TRIM16, and we found that si-TRIM16 reversed the effect of si-EZH2. In vivo studies showed that knockdown of CRABP2 inhibited tumor volume and weight, suppressed the expression of EZH2 and EMT related proteins vimentin and snail, and increased the expression of TRIM16 and E-cadherin.

Physical Training Protects Against Brain Toxicity in Mice Exposed to an Experimental Model of Glioblastoma

Glioma 261 (Gl261) cell-mediated neurotoxicity has been reported in previous studies examining glioblastoma (GBM), and the effects of physical exercise (PE) on this neurotoxicity have been poorly investigated. This study aimed to evaluate the effects of a PE program in animals with experimental GBM. Male C57BL/6J mice were randomized into sham or GBM groups and subjected to a PE program for four weeks. Gl261 cells were administered into the intraventricular region at 48 h after the last exercise session. Body weight, water and feed consumption, and behavior were all evaluated for 21 days followed by euthanasia. The right parietal lobe was removed for the analysis of glial fibrillary acidic protein (GFAP), epidermal growth factor receptor (EGFR), vimentin, C-myc, nuclear factor kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), interleukin 6 (IL-6), hydrogen peroxide, the glutathione system, and oxidative damage to proteins. The results revealed changes in the behavioral patterns of the trained animals, and no anatomopathological changes were observed in response to PE training. In contrast, animals with GBM subjected to PE exhibited lower immunoexpression of c-MYC, vimentin, and GFAP. Although experimental GBM altered the redox profile and inflammatory mediators, no significant alterations were observed after PE. In conclusion, our data provide consistent evidence of the relationship between PE and the improvement of tumorigenic parameters against the neurotoxicity of GL261 cells.

Krüppel-like transcription factor 16 transcriptional up-regulation of cellular retinoic acid-binding proteins-2 promotes the invasion and migration and inhibits apoptosis of retinoblastoma cells by regulating integrin-β1/focal adhesion kinase /extracellular signal-regulated kinase pathway

As a common intraocular malignancy in pediatrics, retinoblastoma (RB) has high prevalence worldwide. We conducted this study, aiming to explore the molecular mechanism of Krüppel-like transcription factor 16 (KLF16)/cellular retinoic acid-binding proteins-2 (CRABP2) in regulating the invasion and migration and apoptosis of RB cells via integrin-β1/focal adhesion kinase (FAK)/extracellular signal-regulated kinase (ERK) pathway. With the adoption of real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot, the mRNA and protein expression of CRABP2 and KLF16 were measured. In addition, the proliferation, clone formation ability and migration were detected with methyl thiazolyl tetrazolium (MTT), clone formation and wound healing assays, respectively. Furthermore, the invasion and apoptosis of transfected WERI-RB1 cells were evaluated with transwell and Tunel assays. With the application of Western blot, the expressions of proliferation-, apoptosis- and pathway-related proteins were assayed. The combination of KLF16 and CRABP2 was confirmed by dual-luciferase reporter assay and chromatin immunoprecipitation (ChIP). In this study, we found that CRABP2 gained a huge growth in RB cells and its silence promoted apoptosis but suppressed the proliferation, migration and invasiveness of WERI-RB1 cells. In addition, KLF16 could bind to CRABP2. It was also found that KLF16 overexpression reversed the effects of CRABP2 silence on the proliferation, migration and apoptosis of WERI-RB1 cells. What is more, CRABP2 silence blocked integrin-β1/FAK/ERK signaling pathway. In conclusion, KLF16 transcriptional up-regulation of CRABP2 promoted proliferation, invasion and migration but inhibited apoptosis of RB cells by activating integrin-β1/FAK/ERK pathway.

Expression and function analysis of CRABP2 and FABP5, and their ratio in esophageal squamous cell carcinoma

Objective

The purpose of this study was to explore the effect of CRABP2 and FABP5, and their ratio on prognosis in esophageal squamous cell carcinoma.

Methods

The expression data of CRABP2 in esophageal cancer in TCGA and GEO were collected by the public database GEPIA. The expression levels of CRABP2 and FABP5 were examined using immunohistochemistry. The relationship between the two proteins and related clinicopathological parameters were analyzed by χ² test. Survival analysis was used to investigate the effect of CRABP2 and FABP5, and their ratio on prognosis.

Results

Compared with normal esophageal mucosal epithelium, there was lower CRABP2 gene mRNA in the esophageal cancer tissue, and the difference was statistically significant (p < 0.01). For the expression level, no significant difference was observed in patients with stages I–IV in esophageal cancer. Immunohistochemistry showed that CRABP2 and FABP5 were both highly expressed in normal esophageal squamous epithelial cells at 100 and 94.1%, while lower in ESCC (75.6 and 58.7%). There was a significant difference in the expression between cancer and adjacent tissues (p < 0.001). No inherent relationship was manifested between the CRABP2 expression and the clinical parameters of the ESCC. The expression of FABP5 was related to lymph node metastasis (p = 0.032), the depth of invasion (p = 0.041), and the AJCC stage (p = 0.013). The ratio of CRABP2 and FABP5 was related to ethnicity (p = 0.001), nerve invasion (p = 0.031), and postoperative treatment (p = 0.038). CRABP2 is positively associated with FABP5 (r = 0.156, p = 0.041) and the ratio (r = 0.334, p = 0.000), while there was a negative correlation between FABP5 and the ratio (r = −0.269, p = 0.000). Patients with CRABP2-positive expression had a significantly longer overall survival than patients with CRABP2-negative expression (p = 0.025).

Conclusion

CRABP2 as a suppressor factor is expected to be a potential prognosis marker for esophageal squamous cell carcinoma.

Cellular Retinoic-Acid Binding Protein 2 in Solid Tumor

The retinoic acid (RA) signaling pathway is crucial for many biological processes. The RA transporter, Cellular Retinoic-Acid Binding Protein 2 (CRABP2), is abnormally expressed in various tumor types. CRABP2 presents significant effects on tumorous behaviors and functions, including cell proliferation, apoptosis, invasion, migration, metastasis, and angiogenesis. The tumorigenesis mechanism of CRABP2, as both suppressor and promotor, is complicated, therefore, there remains the need for further investigation. Elucidating the regulating mechanisms in a specific stage of the tumor could facilitate CRABP2 to be a biomarker in cancer diagnosis and prognosis. Besides, clarifying the pathways of CRABP2 in cancer development will contribute to the gene-targeted therapy. In this review, we summarized the expression, distribution, and mechanism of CRABP2 in solid tumors. Illuminating the CRABP2 signaling pathway may benefit understanding the retinoid signaling pathway, providing a useful biomarker for future clinical trials.

Crabp2 Promotes Metastasis of Lung Cancer Cells via HuR and Integrin β1/FAK/ERK Signaling

Increased Crabp2 levels have been found in various types of cancer, and are associated with poor patients’ survival. Although Crabp2 is found to be overexpressed in lung cancer, its role in metastasis of lung cancer is unclear. In this study, Crabp2 was overexpressed in high-metastatic C10F4 than low-metastatic lung cancer cells. Analysis of clinical samples revealed that high CRABP2 levels were correlated with lymph node metastases, poor overall survival, and increased recurrence. Knockdown of Crabp2 decreased migration, invasion, anoikis resistance, and in vivo metastasis. Crabp2 was co-immunoprecipitated with HuR, and overexpression of Crabp2 increased HuR levels, which promoted integrin β1/FAK/ERK signaling. Inhibition of HuR or integrin β1/FAK/ERK signaling reversed the promoting effect of Crabp2 in migration, invasion, and anoikis resistance. Knockdown of Crabp2 further inhibited the growth of cancer cells as compared with that by gemcitabine or irinotecan alone. The expression of Crabp2 in human lung tumors was correlated with stress marker CHOP. In conclusion, our findings have identified the promoting role of Crabp2 in anoikis resistance and metastasis. CRABP2 may serve as a prognostic marker and targeting CRABP2 may be exploited as a modality to reduce metastasis.

Maintenance chemotherapy to reduce the risk of a metachronous Wilms tumor in children with bilateral nephroblastomatosis

From 2009 to 2018, 10 consecutive patients with Wilms tumors and bilateral nephroblastomatosis, who had completed standard therapy, were provided a maintenance chemotherapy regimen consisting of vincristine and dactinomycin every 3 months for 12 months in order to prevent an early metachronous Wilms tumor. One patient (10%) with Beckwith-Wiedemann syndrome developed a new tumor, without anaplasia. There were no significant toxicities reported during maintenance. All patients are currently alive with no evidence of disease. Further investigations are recommended to determine the utility of this approach.