CRP2, a new invadopodia actin bundling factor critically promotes breast cancer cell invasion and metastasis

Exposure to the phthalate metabolite MEHP impacts survival and growth of human ovarian follicles in vitro

Phthalates are found in everyday items like plastics and personal care products. There is an increasing concern that continuous exposure can adversely affect female fertility. However, experimental data are lacking to establish causal links between exposure and disease in humans. To address this gap, we tested the effects of a common phthalate metabolite, mono-(2-ethylhexyl) phthalate (MEHP), on adult human ovaries in vitro using an epidemiologically determined human-relevant concentration range (2.05 nM - 20.51 mM). Histomorphological assessments, steroid and cytokine measurements were performed on human ovarian tissue exposed to MEHP for 7 days in vitro. Cell viability and gene expression profile were investigated following 7 days of MEHP exposure using the human granulosa cancer cell lines KGN, and COV434, the germline tumor cell line PA-1, and human ovarian primary cells. Selected differentially expressed genes (DEGs) were validated by RT-qPCR and immunofluorescence in human ovarian tissue. MEHP exposure reduced follicular growth (20.51 nM) and increased follicular degeneration (20.51 mM) in ovarian tissue, while not affecting steroid and cytokine production. Out of the 691 unique DEGs identified across all the cell types and concentrations, CSRP2 involved in cytoskeleton organization and YWHAE as well as CTNNB1 involved in the Hippo pathway, were chosen for further validation. CSRP2 was upregulated and CTNNB1 downregulated in both ovarian tissue and cells, whereas YWHAE was downregulated in cells only. In summary, one-week MEHP exposure of human ovarian tissue can perturb the development and survival of human follicles through mechanisms likely involving dysregulation of cytoskeleton organization and Hippo pathway.

Cysteine and glycine-rich protein 2 is crucial for maintaining the malignant phenotypes of gliomas through its action on Notch signalling cascade

Cysteine and glycine-rich protein 2 (CSRP2) is expressed differently in numerous cancers and plays a key role in carcinogenesis. However, the role of CSRP2 in glioma is unknown. This study sought to determine the expression profile and clinical significance of CSRP2 in glioma and explore its biological functions and mechanisms via lentivirus-mediated CSRP2 silencing experiments. Increased CSRP2 was frequently observed in gliomas, which was associated with clinicopathological characteristics and an unfavourable prognosis. Decreasing CSRP2 led to the suppression of malignant proliferation, metastasis and stemness in glioma cells while causing hypersensitivity to chemotherapeutic drugs. Mechanistic investigations revealed that CSRP2 plays a role in mediating the Notch signalling cascade. Silencing CSRP2 decreased the levels of Notch1, cleaved Notch1, HES1 and HEY1, suppressing the Notch signalling cascade. Reactivation of Notch markedly diminished the tumour-inhibiting effects of CSRP2 silencing on the malignant phenotypes of glioma cells. Notably, CSRP2-silencing glioma cells exhibited reduced potential in the formation of xenografts in nude mice in vivo, which was associated with an impaired Notch signalling cascade. These results showed that CSRP2 is overexpressed in glioma and has a crucial role in sustaining the malignant phenotypes of glioma, suggesting that targeting CSRP2 could be a promising strategy for glioma treatment.

Cysteine and glycine-rich protein 3 (Crp3) as a critical regulator of elastolysis, inflammation, and smooth muscle cell apoptosis in abdominal aortic aneurysm development

Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease for which surgical or endovascular repair are the only currently available therapeutic strategies. The development of AAA involves the breakdown of elastic fibers (elastolysis), infiltration of inflammatory cells, and apoptosis of smooth muscle cells (SMCs). However, the specific regulators governing these responses remain unknown. We previously demonstrated that Cysteine and glycine-rich protein 3 (Crp3) sensitizes SMCs to apoptosis induced by stretching. Building upon this finding, we aimed to investigate the influence of Crp3 on elastolysis and apoptosis during AAA development. Using the elastase-CaCl2 rat model, we observed an increase in Crp3 expression, aortic diameter, and a reduction in wall thickness in wild type rats. In contrast, Crp3-/- rats exhibited a decreased incidence of AAA, with minimal or no changes in aortic diameter and thickness. Histopathological analysis revealed the absence of SMC apoptosis and degradation of elastic fibers in Crp3-/- rats, accompanied by reduced inflammation and diminished proteolytic capacity in Crp3-/- SMCs and bone marrow-derived macrophages. Collectively, our findings provide evidence that Crp3 plays a crucial role in AAA development by modulating elastolysis, inflammation, and SMC apoptosis. These results underscore the potential significance of Crp3 in the context of AAA progression and offer new insights into therapeutic targets for this disease.

CSRP2 transcript levels after consolidation therapy increase prognostic prediction ability in B-cell acute lymphoblastic leukaemia

Quantification of measurable residual disease (MRD) correlates with the risk of leukemia recurrence in adults with B-cell acute lymphoblastic leukemia (ALL). However, it remains unknown whether collecting data on cysteine and glycine-rich protein 2 (CSRP2) transcript levels, after completing the second course of consolidation, improves prognosis prediction accuracy. A total of 204 subjects with B-cell ALL were tested for CSPR2 transcripts after completing the second course of consolidation using quantitative real-time polymerase chain reaction (qRT-PCR) and divided into high (N = 32) and low (N = 172) CSRP2 expression cohorts. In multivariable analyses, subjects with high expression of CSRP2 had a higher 5-year cumulative incidence of relapse (CIR) (hazard ratio [HR] = 2.57, 95% confidence interval [CI] 1.38-4.76; P = 0.003), lower 5-year relapse-free survival (RFS) (HR = 3.22, 95% CI 1.75-5.93; P < 0.001), and overall survival (OS) (HR = 4.59, 95% CI 2.64-7.99; P < 0.001) in the whole cohort, as well as in the multi-parameter flow cytometry (MPFC) MRD-negative cohort (for CIR, HR = 2.70, 95% CI 1.19-6.12; for RFS, HR = 4.37, 95% CI 1.94-9.85; for OS, HR = 4.90, 95% CI 2.43-9.90; all P < 0.05). Prognostic analysis showed that allogeneic hematopoietic stem cell transplantation (allo-HSCT) could significantly improve the prognosis of patients with high CSRP2 expression (allo-HSCT vs chemotherapy: 5-year CIR, 52% vs 91%; RFS, 41% vs 9%; OS, 38% vs 20%; all P < 0.05). Our data indicate that incorporating data from CSPR2 transcript levels to the MRD-testing at the end of the second course of consolidation therapy enhances prognosis prediction accuracy in adults with B-cell ALL.

CSRP2 promotes cell stemness in head and neck squamous cell carcinoma

BACKGROUND

Cysteine-rich protein 2 (CSRP2) is discovered as oncogene. The study aims to investigate the clinical significance and potential mechanism of CSRP2 in head and neck squamous cell carcinoma (HNSCC).

METHODS

CSRP2 expression was explored by immunohistochemistry tissue microarrays and Western blotting in HNSCC. The effect of CSRP2 on the cancer stemness and epithelial-to-mesenchymal transition (EMT) of HNSCC cells was investigated by sphere formation, wound healing, and transwell assays. The vitro and vivo experiments revealed that CSRP2 modulated cancer stemness and EMT phenotypes in HNSCC.

RESULTS

CSRP2 was overexpressed in HNSCC patients and presented poor prognosis. CSRP2 knockdown inhibited the migration and invasion ability of the HNSCC cells. And CSRP2 expression was closely associated with CSCs markers, EMT-transcription factor, new oncoprotein, and immune checkpoint.

CONCLUSION

The overexpression of CSRP2 indicates poor prognosis and plays a key role in maintaining the cancer cell stemness and EMT.

Actin cytoskeleton depolymerization increases matrix metalloproteinase gene expression in breast cancer cells by promoting translocation of cysteine-rich protein 2 to the nucleus

The actin cytoskeleton plays a critical role in cancer cell invasion and metastasis; however, the coordination of its multiple functions remains unclear. Actin dynamics in the cytoplasm control the formation of invadopodia, which are membrane protrusions that facilitate cancer cell invasion by focusing the secretion of extracellular matrix-degrading enzymes, including matrix metalloproteinases (MMPs). In this study, we investigated the nuclear role of cysteine-rich protein 2 (CRP2), a two LIM domain-containing F-actin-binding protein that we previously identified as a cytoskeletal component of invadopodia, in breast cancer cells. We found that F-actin depolymerization stimulates the translocation of CRP2 into the nucleus, resulting in an increase in the transcript levels of pro-invasive and pro-metastatic genes, including several members of the MMP gene family. We demonstrate that in the nucleus, CRP2 interacts with the transcription factor serum response factor (SRF), which is crucial for the expression of MMP-9 and MMP-13. Our data suggest that CRP2 and SRF cooperate to modulate of MMP expression levels. Furthermore, Kaplan-Meier analysis revealed a significant association between high-level expression of SRF and shorter overall survival and distant metastasis-free survival in breast cancer patients with a high CRP2 expression profile. Our findings suggest a model in which CRP2 mediates the coordination of cytoplasmic and nuclear processes driven by actin dynamics, ultimately resulting in the induction of invasive and metastatic behavior in breast cancer cells.

Role of CRP2-MRTF interaction in functions of myofibroblasts

Inflammatory response induces phenotypic modulation of fibroblasts into myofibroblasts. Although transforming growth factor-βs (TGF-βs) evoke such transition, the details of the mechanism are still unknown. Here, we report that a LIM domain protein, cysteine-and glycine-rich protein 2 (CSRP2 [CRP2]) plays a vital role in the functional expression profile in myofibroblasts and cancer-associated fibroblasts (CAFs). Knock-down of CRP2 severely inhibits the expression of smooth muscle cell (SMC) genes, cell motility, and CAF-mediated collective invasion of epidermoid carcinoma. We elucidate the following molecular bases: CRP2 directly binds to myocardin-related transcription factors (MRTF-A/B [MRTFs]) and serum response factor (SRF) and stabilizes the MRTF/SRF/CArG-box complex to activate SMC gene expression. Furthermore, a three-dimensional structural analysis of CRP2 identifies the amino acids required for the CRP2-MRTF-A interaction. Polar amino acids in the C-terminal half (serine-152, glutamate-154, serine-155, threonine-156, threonine-157, and threonine-159 in human CRP2) are responsible for direct binding to MRTF-A. On the other hand, hydrophobic amino acids outside the consensus sequence of the LIM domain (tryptophan-139, phenylalanine-144, leucine-153, and leucine-158 in human CRP2) play a role in stabilizing the unique structure of the LIM domain.Key words: CRP2, 3D structure, myocardin-related transcription factor, myofibroblast, cancer-associated fibroblasts.

Cysteine and glycine rich protein 2 exacerbates vascular fibrosis in pulmonary hypertension through the nuclear translocation of yes-associated protein and transcriptional coactivator with PDZ-binding motif

Pulmonary hypertension (PH) is a serious cardiovascular disease with a poor prognosis and high mortality. The pathogenesis of PH is complex, and the main pathological changes in PH are abnormal hypertrophy and vessel stiffness. Cysteine and glycine rich protein 2 (Csrp2), a member of the LIM-only family plays a key role in the response to vascular injury. However, its roles in vascular fibrosis and PH have not been clarified. Therefore, this study aimed to investigate whether Csrp2 can promote vascular fibrosis and to further explore the possible mechanisms. Csrp2 expression was increased in both the pulmonary vasculature of rats with PH and hypoxic pulmonary vascular smooth muscle cells (PASMCs). Hypoxia activated TGF-β1 and its downstream effector, SP1. Additionally, hypoxia activated the ROCK pathway and inhibited KLF4 expression. Silencing SP1 and overexpressing KLF4 reversed the hypoxia-induced increase in Csrp2 expression. Csrp2 knockdown decreased the expression of extracellular matrix (ECM) proteins and inhibited the nuclear translocation and expression of YAP/TAZ in hypoxic PASMCs. These results indicate that hypoxia induces Csrp2 expression through the TGF-β1/SP1 and ROCK/KLF4 pathways. Elevated Csrp2 promoted the nuclear translocation and expression of YAP/TAZ, leading to vascular fibrosis and the development of PH.

Cysteine and glycine-rich protein 2 promotes hypoxic pulmonary vascular smooth muscle cell proliferation through the Wnt3α-β-catenin/lymphoid enhancer-binding factor 1 pathway

Pulmonary hypertension (PH) is mainly characterized by abnormal pulmonary vascular hyperplasia and vascular remodeling, but its mechanism is complicated and currently unclear. Cysteine and glycine-rich protein 2 (Csrp2) has been reported to promote cell proliferation and migration, and affect cell cycle progression. As a new invasive actin-binding factor, Csrp2 increased the invasion and even metastasis of some cancer cells. It was associated with tumor recurrence and chemotherapy resistance. However, the role of Csrp2 in PH remains unknown. We found that Csrp2 expression was increased both in pulmonary arteries (PAs) and smooth muscle cells (PASMCs) in PH. Csrp2 enhanced PASMC proliferation and phenotypic transition. The Wnt3α-β-catenin/lymphoid enhancer-binding factor 1 (LEF1) pathway is involved in cell proliferation and phenotypic transition regulated by Csrp2 expression. These results suggest that hypoxia downregulates YinYang-1 (YY1) and then increases Csrp2 expression. Increased Csrp2 promotes PASMC proliferation and phenotypic transition by activating the Wnt3α-β-catenin/LEF1 pathways, which leads to pulmonary vascular remodeling and even provides a new theoretical basis for studying the pathogenesis and therapeutic targets of PH.

Spontaneous Formation of 3D Breast Cancer Tissues on Electrospun Chitosan/Poly(ethylene oxide) Nanofibrous Scaffolds

Three-dimensional (3D) tissue culture has attracted a great deal of attention as a result of the need to replace the conventional two-dimensional cell cultures with more meaningful methods, especially for understanding the sophisticated nature of native tumor microenvironments. However, most techniques for 3D tissue culture are laborious, expensive, and limited to spheroid formation. In this study, a low-cost and highly effective nanofibrous scaffold is presented for spontaneous formation of reproducible 3D breast cancer microtissues. Experimentally, aligned and non-aligned chitosan/poly(ethylene oxide) nanofibrous scaffolds were prepared at one of two chitosan concentrations (2 and 4 wt %) and various electrospinning parameters. The resulting fabricated scaffolds (C2P1 and C4P1) were structurally and morphologically characterized, as well as analyzed in silico. The obtained data suggest that the fiber diameter, surface roughness, and scaffold wettability are tunable and can be influenced based on the chitosan concentration, electrospinning conditions, and alignment mode. To test the usefulness of the fabricated scaffolds for 3D cell culture, a breast cancer cell line (MCF-7) was cultured on their surfaces and evaluated morphologically and biochemically. The obtained data showed a higher proliferation rate for cells grown on scaffolds compared to cells grown on two-dimensional adherent plates (tissue culture plate). The MTT assay revealed that the rate of cell proliferation on nanofibrous scaffolds is statistically significantly higher compared to tissue culture plate (P ≤ 0.001) after 14 days of culture. The formation of spheroids within the first few days of culture shows that the scaffolds effectively support 3D tissue culture from the outset of the experiment. Furthermore, 3D breast cancer tissues were spontaneously formed within 10 days of culture on aligned and non-aligned nanofibrous scaffolds, which suggests that the scaffolds imitate the in vivo extracellular matrix in the tumor microenvironment. Detailed mechanisms for the spontaneous formation of the 3D microtissues have been proposed. Our results suggest that scaffold surface topography significantly influences tissue formation and behavior of the cells.

Cross-reactivity of a pathogenic autoantibody to a tumor antigen in GABAA receptor encephalitis

Encephalitis associated with antibodies against the neuronal gamma-aminobutyric acid A receptor (GABA_A-R) is a rare form of autoimmune encephalitis. The pathogenesis is still unknown but autoimmune mechanisms were surmised. Here we identified a strongly expanded B cell clone in the cerebrospinal fluid of a patient with GABA_A-R encephalitis. We expressed the antibody produced by it and showed by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry that it recognizes the GABA_A-R. Patch-clamp recordings revealed that it tones down inhibitory synaptic transmission and causes increased excitability of hippocampal CA1 pyramidal neurons. Thus, the antibody likely contributed to clinical disease symptoms. Hybridization to a protein array revealed the cross-reactive protein LIM-domain-only protein 5 (LMO5), which is related to cell-cycle regulation and tumor growth. We confirmed LMO5 recognition by immunoprecipitation and ELISA and showed that cerebrospinal fluid samples from two other patients with GABA_A-R encephalitis also recognized LMO5. This suggests that cross-reactivity between GABA_A-R and LMO5 is frequent in GABA_A-R encephalitis and supports the hypothesis of a paraneoplastic etiology.

Transcriptomic and Epigenetic Profiling of Fibroblasts in Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic pulmonary fibrosis (IPF), a devastating, fibro-proliferative chronic lung disorder, is associated with expansion of fibroblasts/myofibroblasts, which leads to excessive production and deposition of extracellular matrix (ECM). IPF is typically clinically identified as end-stage lung disease, after fibrotic processes are well-established and advanced. Fibroblasts have been shown to be critically important in the development and progression of IPF. We hypothesize that differential chromatin access can drive genetic differences in IPF fibroblasts relative to healthy fibroblasts. To this end, we performed Assay of Transposase-Accessible Chromatin (ATAC)-sequencing to identify differentially accessible regions within the genomes of fibroblasts from healthy and IPF lungs. Multiple motifs were identified to be enriched in IPF fibroblasts compared to healthy fibroblasts, including binding motifs for TWIST1 and FOXA1. RNA-sequencing identified 93 genes that could be annotated to differentially accessible regions. Pathway analysis of the annotated genes identified cellular adhesion, cytoskeletal anchoring, and cell differentiation as important biological processes. In addition, single nucleotide polymorphisms (SNPs) analysis showed that linkage disequilibrium (LD) blocks of IPF risk SNPs with IPF accessible regions that have been identified to be located in genes which are important in IPF, including MUC5B, TERT and TOLLIP. Validation studies in isolated lung tissue confirmed increased expression for TWIST1 and FOXA1 in addition to revealing SHANK2 and CSPR2 as novel targets. Thus, modulation of differential chromatin access may be an important mechanism in the pathogenesis of lung fibrosis.

The multiple roles of actin-binding proteins at invadopodia

Invadopodia are actin-rich membrane protrusions that facilitate cancer cell dissemination by focusing on proteolytic activity and clearing paths for migration through physical barriers, such as basement membranes, dense extracellular matrices, and endothelial cell junctions. Invadopodium formation and activity require spatially and temporally regulated changes in actin filament organization and dynamics. About three decades of research have led to a remarkable understanding of how these changes are orchestrated by sequential recruitment and coordinated activity of different sets of actin-binding proteins. In this chapter, we provide an update on the roles of the actin cytoskeleton during the main stages of invadopodium development with a particular focus on actin polymerization machineries and production of pushing forces driving extracellular matrix remodeling.

Intracellular and Extracellular Markers of Lethality in Osteogenesis Imperfecta: A Quantitative Proteomic Approach

Osteogenesis imperfecta (OI) is a heritable disorder that mainly affects the skeleton. The inheritance is mostly autosomal dominant and associated to mutations in one of the two genes, COL1A1 and COL1A2, encoding for the type I collagen α chains. According to more than 1500 described mutation sites and to outcome spanning from very mild cases to perinatal-lethality, OI is characterized by a wide genotype/phenotype heterogeneity. In order to identify common affected molecular-pathways and disease biomarkers in OI probands with different mutations and lethal or surviving phenotypes, primary fibroblasts from dominant OI patients, carrying COL1A1 or COL1A2 defects, were investigated by applying a Tandem Mass Tag labeling-Liquid Chromatography-Tandem Mass Spectrometry (TMT LC-MS/MS) proteomics approach and bioinformatic tools for comparative protein-abundance profiling. While no difference in α1 or α2 abundance was detected among lethal (type II) and not-lethal (type III) OI patients, 17 proteins, with key effects on matrix structure and organization, cell signaling, and cell and tissue development and differentiation, were significantly different between type II and type III OI patients. Among them, some non-collagenous extracellular matrix (ECM) proteins (e.g., decorin and fibrillin-1) and proteins modulating cytoskeleton (e.g., nestin and palladin) directly correlate to the severity of the disease. Their defective presence may define proband-failure in balancing aberrances related to mutant collagen.

Coefficient of variation as an image-intensity metric for cytoskeleton bundling

The evaluation of cytoskeletal bundling is a fundamental experimental method in the field of cell biology. Although the skewness of the pixel intensity distribution derived from fluorescently-labeled cytoskeletons has been widely used as a metric to evaluate the degree of bundling in digital microscopy images, its versatility has not been fully validated. Here, we applied the coefficient of variation (CV) of intensity values as an alternative metric, and compared its performance with skewness. In synthetic images representing extremely bundled conditions, the CV successfully detected degrees of bundling that could not be distinguished by skewness. On actual microscopy images, CV was better than skewness, especially on variable-angle epifluorescence microscopic images or stimulated emission depletion and confocal microscopy images of very small areas of around 1 μm2. When blur or noise was added to synthetic images, CV was found to be robust to blur but deleteriously affected by noise, whereas skewness was robust to noise but deleteriously affected by blur. For confocal images, CV and skewness showed similar sensitivity to noise, possibly because optical blurring is often present in microscopy images. Therefore, in practical use with actual microscopy images, CV may be more appropriate than skewness, unless the image is extremely noisy.

Inhibition of CSRP2 Promotes Leukemia Cell Proliferation and Correlates with Relapse in Adults with Acute Myeloid Leukemia

Background

Relapse is a major obstacle in the treatment of acute myeloid leukemia (AML). Refinement of risk stratification may aid the identification of patients who are likely to relapse. Abnormal cysteine and glycine-rich protein 2 (CSRP2) has been implicated in various cancers, but its function remains unclear. The purpose of this study was to explore the role of CSRP2 in predicting adult AML recurrence.

Methods

RT-PCR was used to detect the expression of CSRP2 in 193 newly diagnosed adult AML patients and 44 healthy controls. The competitive risk model was used to calculate the cumulative incidence of relapse rate (CIR), Kaplan-Meier to calculate the relapse-free survival rate (RFS), and the Cox regression model to perform multivariate analysis. Viral transfection was used to construct AML cell lines with stable knockdown of CSRP2, CCK8 to detect proliferation and drug resistance, flow cytometry to detect cell cycle and apoptosis, and Western blot to detect key molecules in signaling pathways.

Results

CSRP2 transcript levels were higher in 193 adult AML compared with 44 healthy controls. In 149 patients who achieved complete remission, those with high CSRP2 transcript levels displayed a lower 2-year CIR and higher 2-year RFS, especially when receiving only chemotherapy. In multivariate analysis, a high CSRP2 transcript level was independently associated with a better RFS. Knockdown of CSRP2 promoted proliferation and cell cycle progression, and reduced chemosensitivity. Western blot analysis showed upregulation of p-AKT and p-CREB in CSRP2-knockdown AML cell lines. Inhibition assays suggested these two signaling pathways participated in the CSRP2-mediated proliferation effects in AML cell lines.

Conclusion

In summary, CSRP2 correlates with relapse in adult AML. Down-regulation of CSRP2 could promote the proliferation of AML cell lines by regulating the AKT and CREB signaling pathways. Therefore, CSRP2 may provide prognostic significance and potential therapeutic targets in the management of AML.

Claudin 1 inhibits cell migration and increases intercellular adhesion in triple-negative breast cancer cell line

Triple-negative "claudin 1 low" subtype represents around 15% of breast cancer and displays poor prognosis. The loss of claudin 1 is correlated with increased invasiveness and higher recurrence of the disease. Claudin 1 constitutes the backbone of the tight junction and is involved in cell-cell adhesion and migration processes. However, studies showed a controversial role of claudin 1 in cell migration. In this study, we aimed to clarify the effect of claudin 1 on migration of mesenchymal triple-negative breast cancer cells (TNBC). We reported that transient over expression of claudin 1 in MDA-MB-231 and Hs578T "claudin 1 low" TNBC cells inhibited cell migration using wound healing and transwell migration assays. In order to investigate more specifically the involvement of claudin 1, we generated stable MDA-MB-231 clones overexpressing claudin 1. Interestingly, the level of claudin 1 was correlated to the inhibition of cell migration and to the increase of cell-cell aggregation associated with enhanced formation of β-catenin adherens junction and occludin tight junction. Finally, we reported for the first time the key role of claudin 1 in the inhibition of cell migration process associated with the disappearance of stress fibers. These data suggest that re-expression of claudin 1 could be a promising strategy for regulating the migration of TNBC which no longer express claudin 1.

CSRP2 suppresses colorectal cancer progression via p130Cas/Rac1 axis-meditated ERK, PAK, and HIPPO signaling pathways

Metastasis is a major cause of death in patients with colorectal cancer (CRC). Cysteine-rich protein 2 (CSRP2) has been recently implicated in the progression and metastasis of a variety of cancers. However, the biological functions and underlying mechanisms of CSRP2 in the regulation of CRC progression are largely unknown.

Methods: Immunohistochemistry, quantitative real-time polymerase chain reaction (qPCR) and Western blotting (WB) were used to detect the expression of CSRP2 in CRC tissues and paracancerous tissues. CSRP2 function in CRC was determined by a series of functional tests in vivo and in vitro. WB and immunofluorescence were used to determine the relation between CSRP2 and epithelial-mesenchymal transition (EMT). Co-immunoprecipitation and scanning electron microscopy were used to study the molecular mechanism of CSRP2 in CRC.

Results: The CSRP2 expression level in CRC tissues was lower than in adjacent normal tissues and indicated poor prognosis in CRC patients. Functionally, CSRP2 could suppress the proliferation, migration, and invasion of CRC cells in vitro and inhibit CRC tumorigenesis and metastasis in vivo. Mechanistic investigations revealed a physical interaction between CSRP2 and p130Cas. CSRP2 could inhibit the activation of Rac1 by preventing the phosphorylation of p130Cas, thus activating the Hippo signaling pathway, and simultaneously inhibiting the ERK and PAK/LIMK/cortactin signaling pathways, thereby inhibiting the EMT and metastasis of CRC. Rescue experiments showed that blocking the p130Cas and Rac1 activation could inhibit EMT induced by CSRP2 silencing.

Conclusion: Our results suggest that the CSRP2/p130Cas/Rac1 axis can inhibit CRC aggressiveness and metastasis through the Hippo, ERK, and PAK signaling pathways. Therefore, CSRP2 may be a potential therapeutic target for CRC.

Identification of Potential Chemical Substrates as Fuel for Hypoxic Tumors That May Be Linked to Invadopodium Formation in Hypoxia-Induced MDA-MB-231 Breast-Cancer Cell Line

Hypoxia plays a significant role in solid tumors by the increased expression of hypoxia-inducible factor-1α (HIF-1α), which is known to promote cancer invasion and metastasis. Cancer-cell invasion dynamically begins with the degradation of the extracellular matrix (ECM) via invadopodia formation. The chemical substrates that are utilized by hypoxic cells as fuel to drive invadopodia formation are still not fully understood. Therefore, the aim of the study was to maintain MDA-MB-231 cells under hypoxia conditions to allow cells to form a large number of invadopodia as a model, followed by identifying their nutrient utilization. The results of the study revealed an increase in the number of cells forming invadopodia under hypoxia conditions. Moreover, Western blot analysis confirmed that essential proteins for hypoxia and invadopodia, including HIF-1α, vascular endothelial growth factor (VEGF), metallopeptidase-2 (MMP-2), and Rho guanine nucleotide exchange factor 7 (β-PIX), significantly increased under hypoxia. Interestingly, phenotype microarray showed that only 11 chemical substrates from 367 types of substrates were significantly metabolized in hypoxia compared to in normoxia. This is thought to be fuel for hypoxia to drive the invasion process. In conclusion, we found 11 chemical substrates that could have potential energy sources for hypoxia-induced invadopodia formation of these cells. This may in part be a target in the hypoxic tumor and invadopodia formation. Additionally, these findings can be used as potential carrier targets in cancer-drug discovery, such as the usage of dextrin.

An Overview of the Cytoskeleton-Associated Role of PDLIM5

Regenerative medicine represented by stem cell technology has become one of the pillar medical technologies for human disease treatment. Cytoskeleton plays important roles in maintaining cell morphology, bearing external forces, and maintaining the effectiveness of cell internal structure, among which cytoskeleton related proteins are involved in and play an indispensable role in the changes of cytoskeleton. PDLIM5 is a cytoskeleton-related protein that, like other cytoskeletal proteins, acts as a binding protein. PDZ and LIM domain 5 (PDLIM5), also known as ENH (Enigma homolog), is a cytoplasmic protein with a molecular mass of about 63 KDa that consists of a PDZ domain at the N-terminus and three LIM domains at the C-terminus. PDLIM5 binds to the cytoskeleton and membrane proteins through its PDZ domain and interacts with various signaling molecules, including protein kinases and transcription factors, through its LIM domain. As a cytoskeleton-related protein, PDLIM5 plays an important role in regulating cell proliferation, differentiation and cell fate decision in multiple tissues and cell types. In this review, we briefly summarize the state of knowledge on the PDLIM5 gene, structural properties, and molecular functional mechanisms of the PDLIM5 protein, and its role in cells, tissues, and organ systems, and describe the possible underlying molecular signaling pathways. In the last part of this review, we will focus on discussing the limitations of existing research and the future prospects of PDLIM5 research in turn.

Gemcitabine-induced epithelial-mesenchymal transition-like changes sustain chemoresistance of pancreatic cancer cells of mesenchymal-like phenotype

Growing body of evidence suggests that epithelial-mesenchymal transition (EMT) is a critical process in tumor progression and chemoresistance in pancreatic cancer (PC). The aim of this study was to analyze the role of EMT-like changes in acquisition of resistance to gemcitabine in pancreatic cells of the mesenchymal or epithelial phenotype. Therefore, chemoresistant BxPC-3, Capan-2, Panc-1, and MiaPaca-2 cells were selected by chronic exposure to increasing concentrations of gemcitabine. We show that gemcitabine-resistant Panc-1 and MiaPaca-2 cells of mesenchymal-like phenotype undergo further EMT-like molecular changes mediated by ERK-ZEB-1 pathway, and that inhibition of ERK1/2 phosphorylation or ZEB-1 expression resulted in a decrease in chemoresistance. Conversely, gemcitabine-resistant BxPC-3 and Capan-2 cells of epithelial-like phenotype did not show such typical EMT-like molecular changes although the expression of the tight junction marker occludin could be found decreased. In pancreatic cancer patients, high ZEB-1 expression was associated with tumor invasion and tumor budding. In addition, tumor budding was essentially observed in patients treated with neoadjuvant chemotherapy. These findings support the notion that gemcitabine treatment induces EMT-like changes that sustain invasion and chemoresistance in PC cells.

New Insights for RANKL as a Proinflammatory Modulator in Modeled Inflammatory Arthritis

Receptor activator of nuclear factor-κB ligand (RANKL), a member of the Tumor Necrosis Factor (TNF) superfamily, constitutes the master regulator of osteoclast formation and bone resorption, whereas its involvement in inflammatory diseases remains unclear. Here, we used the human TNF transgenic mouse model of erosive inflammatory arthritis to determine if the progression of inflammation is affected by either genetic inactivation or overexpression of RANKL in transgenic mouse models. TNF-mediated inflammatory arthritis was significantly attenuated in the absence of functional RANKL. Notably, TNF overexpression could not compensate for RANKL-mediated osteopetrosis, but promoted osteoclastogenesis between the pannus and bone interface, suggesting RANKL-independent mechanisms of osteoclastogenesis in inflamed joints. On the other hand, simultaneous overexpression of RANKL and TNF in double transgenic mice accelerated disease onset and led to severe arthritis characterized by significantly elevated clinical and histological scores as shown by aggressive pannus formation, extended bone resorption, and massive accumulation of inflammatory cells, mainly of myeloid origin. RANKL and TNF cooperated not only in local bone loss identified in the inflamed calcaneous bone, but also systemically in distal femurs as shown by microCT analysis. Proteomic analysis in inflamed ankles from double transgenic mice overexpressing human TNF and RANKL showed an abundance of proteins involved in osteoclastogenesis, pro-inflammatory processes, gene expression regulation, and cell proliferation, while proteins participating in basic metabolic processes were downregulated compared to TNF and RANKL single transgenic mice. Collectively, these results suggest that RANKL modulates modeled inflammatory arthritis not only as a mediator of osteoclastogenesis and bone resorption but also as a disease modifier affecting inflammation and immune activation.

Actin Cytoskeleton Remodeling Drives Breast Cancer Cell Escape from Natural Killer-Mediated Cytotoxicity

Elucidation of the underlying molecular mechanisms of immune evasion in cancer is critical for the development of immunotherapies aimed to restore and stimulate effective antitumor immunity. Here, we evaluate the role of the actin cytoskeleton in breast cancer cell resistance to cytotoxic natural killer (NK) cells. A significant fraction of breast cancer cells responded to NK-cell attack via a surprisingly rapid and massive accumulation of F-actin near the immunologic synapse, a process we termed "actin response." Live-cell imaging provided direct evidence that the actin response is associated with tumor cell resistance to NK-cell-mediated cell death. High-throughput imaging flow cytometry analyses showed that breast cancer cell lines highly resistant to NK cells were significantly enriched in actin response-competent cells as compared with susceptible cell lines. The actin response was not associated with a defect in NK-cell activation but correlated with reduced intracellular levels of the cytotoxic protease granzyme B and a lower rate of apoptosis in target cells. Inhibition of the actin response by knocking down CDC42 or N-WASP led to a significant increase in granzyme B levels in target cells and was sufficient to convert resistant breast cancer cell lines into a highly susceptible phenotype. The actin response and its protective effects were fully recapitulated using donor-derived primary NK cells as effector cells. Together, these findings establish the pivotal role of actin remodeling in breast cancer cell resistance to NK-cell-mediated killing.Significance: These findings establish the pivotal role of the actin cytoskeleton in driving breast cancer cell resistance to natural killer cells, a subset of cytotoxic lymphocytes with important roles in innate antitumor immunity. Cancer Res; 78(19); 5631-43. ©2018 AACR.

Hypoxia promotes breast cancer cell invasion through HIF-1α-mediated up-regulation of the invadopodial actin bundling protein CSRP2

Hypoxia is a common feature of solid tumours that promotes invasion and metastatic dissemination. Invadopodia are actin-rich membrane protrusions that direct extracellular matrix proteolysis and facilitate tumour cell invasion. Here, we show that CSRP2, an invadopodial actin bundling protein, is upregulated by hypoxia in various breast cancer cell lines, as well as in pre-clinical and clinical breast tumour specimens. We functionally characterized two hypoxia responsive elements within the proximal promoter of CSRP2 gene which are targeted by hypoxia-inducible factor-1 (HIF-1) and required for promoter transactivation in response to hypoxia. Remarkably, CSRP2 knockdown significantly inhibits hypoxia-stimulated invadopodium formation, ECM degradation and invasion in MDA-MB-231 cells, while CSRP2 forced expression was sufficient to enhance the invasive capacity of HIF-1α-depleted cells under hypoxia. In MCF-7 cells, CSRP2 upregulation was required for hypoxia-induced formation of invadopodium precursors that were unable to promote ECM degradation. Collectively, our data support that CSRP2 is a novel and direct cytoskeletal target of HIF-1 which facilitates hypoxia-induced breast cancer cell invasion by promoting invadopodia formation.

Cysteine and glycine-rich protein 2 (CSRP2) transcript levels correlate with leukemia relapse and leukemia-free survival in adults with B-cell acute lymphoblastic leukemia and normal cytogenetics

Relapse is the major cause of treatment-failure in adults with B-cell acute lymphoblastic leukemia (ALL) achieving complete remission after induction chemotherapy. Greater precision identifying persons likely to relapse is important. We did bio-informatics analyses of transcriptomic data to identify mRNA transcripts aberrantly-expressed in B-cell ALL. We selected 9 candidate genes for validation 7 of which proved significantly-associated with B-cell ALL. We next focused on function and clinical correlations of the cysteine and glycine-rich protein 2 (CSRP2). Quantitative real-time polymerase chain reaction (RT-qPCR) was used to examine gene transcript levels in bone marrow samples from 236 adults with B-cell ALL compared with samples from normals. CSRP2 was over-expressed in 228 out of 236 adults (97%) with newly-diagnosed B-cell ALL. A prognostic value was assessed in 168 subjects. In subjects with normal cytogenetics those with high CSRP2 transcript levels had a higher 5-year cumulative incidence of relapse (CIR) and worse relapse-free survival (RFS) compared with subjects with low transcript levels (56% [95% confidence interval, 53, 59%] vs. 19% [18, 20%]; P = 0.011 and 41% [17, 65%] vs. 80% [66–95%]; P = 0.007). In multivariate analyses a high CSRP2 transcript level was independently-associated with CIR (HR = 5.32 [1.64–17.28]; P = 0.005) and RFS (HR = 5.56 [1.87, 16.53]; P = 0.002). Functional analyses indicated CSRP2 promoted cell proliferation, cell-cycle progression, in vitro colony formation and cell migration ability. Abnormal CSRP2 expression was associated with resistance to chemotherapy; sensitivity was restored by down-regulating CSRP2 expression.

Association of genetic variants in lncRNA H19 with risk of colorectal cancer in a Chinese population

Objective

The long non-coding RNA (lncRNA) gene, H19, has been involving in multiple biological functions, which also plays a vital role in colorectal cancer carcinogenesis. However, the association between genetic variants in H19 and colorectal cancer susceptibility has not been reported. In this study, we aim to explore whether H19 polymorphisms are related to the susceptibility of colorectal cancer.

Methods

We conducted a case-control study to evaluate the association between four selected single nucleotide polymorphisms (SNPs) (rs2839698, rs3024270, rs217727, and rs2735971) in H19 and the risk of colorectal cancer in a Chinese population.

Results

We found that individuals with rs2839698 A allele had a significantly increased risk of colorectal cancer, compared to those carrying G allele [odds ratio (OR) = 1.20, 95% confidence interval (CI) = 1.05–1.36 in additive model]. Further stratified analyses revealed that colon tumor site, well differentiated grade and Duke's stage of C/D were significantly associated with colorectal cancer risk (P < 0.05). Additionally, bioinformatic analysis showed that rs2839698 may change the crucial folding structures and alter the target microRNAs of H19.

Conclusions

Our results provided the evidence that rs2839698 in H19 was associated with elevated risk of colorectal cancer, which may be a potential biomarker for predicting colorectal cancer susceptibility.

Cysteine-rich protein 2 accelerates actin filament cluster formation

Filamentous actin (F-actin) forms many types of structures and dynamically regulates cell morphology and movement, and plays a mechanosensory role for extracellular stimuli. In this study, we determined that the smooth muscle-related transcription factor, cysteine-rich protein 2 (CRP2), regulates the supramolecular networks of F-actin. The structures of CRP2 and F-actin in solution were analyzed by small-angle X-ray solution scattering (SAXS). The general shape of CRP2 was partially unfolded and relatively ellipsoidal in structure, and the apparent cross sectional radius of gyration (R_c) was about 15.8 Å. The predicted shape, derived by ab initio modeling, consisted of roughly four tandem clusters: LIM domains were likely at both ends with the middle clusters being an unfolded linker region. From the SAXS analysis, the R_c of F-actin was about 26.7 Å, and it was independent of CRP2 addition. On the other hand, in the low angle region of the CRP2-bound F-actin scattering, the intensities showed upward curvature with the addition of CRP2, which indicates increasing branching of F-actin following CRP2 binding. From biochemical analysis, the actin filaments were augmented and clustered by the addition of CRP2. This F-actin clustering activity of CRP2 was cooperative with α-actinin. Thus, binding of CRP2 to F-actin accelerates actin polymerization and F-actin cluster formation.

Actinin-1 and actinin-4 play essential but distinct roles in invadopodia formation by carcinoma cells

Invadopodia are ventral membrane protrusions formed by cancer cells that degrade the extracellular matrix (ECM) during tumor invasion and metastasis. Formation of invadopodia is initiated by the assembly of actin filaments (F-actin) that results from the coordinated activation of several actin regulatory proteins. Actinin-1 and actinin-4 are actin bundling proteins expressed in non-muscle cells and actinin-4 is preferentially associated with malignant phenotypes of carcinoma cells. In this study, we investigated the role of actinin-1 and -4 in invadopodia formation. Expression of both actinin-1 and -4 tended to be higher in invasive and metastatic breast carcinoma cell lines than in non-invasive ones. Immunofluorescence analysis revealed that actinin-1 and -4 colocalized at core actin structures of invadopodia. Time-lapse imaging showed that appearance of both actinins at invadopodia is concomitant with the assembly of F-actin. Knockdown of either actinin-1 or actinin-4 suppressed the formation of invadopodia and degradation of the ECM by carcinoma cells. Interestingly, overexpression of actinin-4, but not actinin-1, significantly promoted the formation of invadopodia and this activity required the actin binding domains and the unique N-terminal motif that exists only in actinin-4. These results demonstrate that both actinin-1 and actinin-4 participate in the assembly of F-actin at invadopodia. Additionally, actinin-4 may have a selective advantage in accelerating invadopodia-mediated invasion of carcinoma cells.

H19 Noncoding RNA, an Independent Prognostic Factor, Regulates Essential Rb-E2F and CDK8-β-Catenin Signaling in Colorectal Cancer

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High H19 expression in primary tumors is an independent predictor of short overall survival in CRC patients.

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RB1-E2F and CDK8-β-catenin signaling are essential in mediating the oncogenic activity of H19 in CRC.

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Combined analysis of H19 and its targets further improved the prediction power on overall survival of CRC patients.

Long noncoding RNAs (lncRNAs) are transcripts at least 200 nucleotides long that do not code for proteins. The clinical relevance of lncRNAs in colorectal cancer (CRC) is largely unknown. Here we identified that H19 expression in primary tumors is an independent prognostic predictor of poor prognosis of CRC patients and further proved its oncogenic role. To characterize the mechanisms, we profiled gene expression changes following H19 modulation in CRC cell lines and analyzed gene expression association in clinical datasets. Our data revealed important cancer-signaling pathways, including the RB1-E2F and the CDK8-β-catenin signaling, underlying H19 function.

The clinical significance of long noncoding RNAs (lncRNAs) in colorectal cancer (CRC) remains largely unexplored. Here, we analyzed a large panel of lncRNA candidates with The Cancer Genome Atlas (TCGA) CRC dataset, and identified H19 as the most significant lncRNA associated with CRC patient survival. We further validated such association in two independent CRC cohorts. H19 silencing blocked G1-S transition, reduced cell proliferation, and inhibited cell migration. We profiled gene expression changes to gain mechanism insight of H19 function. Transcriptome data analysis revealed not only previously identified mechanisms such as Let-7 regulation by H19, but also RB1-E2F1 function and β-catenin activity as essential upstream regulators mediating H19 function. Our experimental data showed that H19 affects phosphorylation of RB1 protein by regulating gene expression of CDK4 and CCND1. We further demonstrated that reduced CDK8 expression underlies changes of β-catenin activity, and identified that H19 interacts with macroH2A, an essential regulator of CDK8 gene transcription. However, the relevance of H19-macroH2A interaction in CDK8 regulation remains to be experimentally determined. We further explored the clinical relevance of above mechanisms in clinical samples, and showed that combined analysis of H19 with its targets improved prognostic value of H19 in CRC.

MicroRNA Profiling of the Effect of the Heptapeptide Angiotensin-(1-7) in A549 Lung Tumor Cells Reveals a Role for miRNA149-3p in Cellular Migration Processes

Lung cancer is one of the most frequent types of cancer in humans and a leading cause of death worldwide. The high mortality rates are correlated with late diagnosis, which leads to high rates of metastasis found in patients. Thus, despite all the improvement in therapeutic approaches, the development of new drugs that control cancer cell migration and metastasis are required. The heptapeptide angiotensin-(1-7) [ang-(1-7)] has demonstrated the ability to control the growth rates of human lung cancer cells in vitro and in vivo, and the elucidation of central elements that control the fine-tuning of cancer cells migration in the presence of the ang-(1-7), will support the development of new therapeutic approaches. Ang-(1-7) is a peptide hormone of the renin-angiotensin system (RAS) and this study investigates the modulatory effect of the heptapeptide on the expression pattern of microRNAs (miRNAs) in lung tumor cells, to elucidate mechanistic concerns about the effect of the peptide in the control of tumor migratory processes. Our primary aim was to compare the miRNA profiling between treated and untreated-heptapeptide cells to characterize the relevant molecule that modulates cellular migration rates. The analyses selected twenty one miRNAs, which are differentially expressed between the groups; however, statistical analyses indicated miRNA-149-3p as a relevant molecule. Once functional analyses were performed, we demonstrated that miRNA-149-3p plays a role in the cellular migration processes. This information could be useful for future investigations on drug development.