Calponin h1 induced a flattened morphology and suppressed the growth of human fibrosarcoma HT1080 cells

Potential prognostic and immunotherapeutic value of calponin 1: A pan-cancer analysis

Background: Emerging evidence has suggested a pro-oncogenic role of calponin 1 (CNN1) in the initiation of a variety of cancers. Despite this, CNN1 remains unknown in terms of its effects and mechanisms on angiogenesis, prognosis, and immunology in cancer. Materials and Methods: The expression of CNN1 was extracted and analyzed using the TIMER, UALCAN, and GEPIA databases. Meanwhile, we analyzed the diagnostic value of CNN1 by using PrognoScan and Kaplan-Meier plots. To elucidate the value of CNN1 in immunotherapy, we used the TIMER 2.0 database, TISIDB database, and Sangerbox database. Gene set enrichment analysis (GSEA) was used to analyze the expression pattern and bio-progression of CNN1 and the vascular endothelium growth factor (VEGF) in cancer. The expressions of CNN1 and VEGF in gastric cancer were confirmed using immunohistochemistry. We used Cox regression analysis to investigate the association between pathological characteristics, clinical prognosis, and CNN1 and VEGF expressions in patients with gastric cancer. Results: CNN1 expression was higher in normal tissues than it was in tumor tissues of most types of cancers. However, the expression level rebounds during the development of tumors. High levels of CNN1 indicate a poor prognosis for 11 tumors, which include stomach adenocarcinoma (STAD). There is a relationship between CNN1 and tumor-infiltrating lymphocytes (TILs), and the marker genes NRP1 and TNFRSF14 of TILs are significantly related to CNN1 expression in gastric cancers. The GSEA results confirmed the lower expression of CNN1 in tumors when compared to normal tissues. However, CNN1 again showed an increasing trend during tumor development. In addition, the results also suggest that CNN1 is involved in angiogenesis. The immunohistochemistry results validated the GSEA result (take gastric cancer as an example). Cox analysis suggested that high CNN1 expression and high VEGF expression are closely associated with poor clinical prognosis. Conclusion: Our study has shown that CNN1 expression is aberrantly elevated in various cancers and positively correlates with angiogenesis and the immune checkpoint, contributing to cancer progression and poor prognosis. These results suggest that CNN1 could serve as a promising candidate for pan-cancer immunotherapy.

Tissue-Based Proteomic Profiling in Patients with Hyperplasia and Endometrial Cancer

Uterine cancers are among the most prevalent gynecological malignancies, and endometrial cancer (EC) is the most common in this group. This study used tissue-based proteomic profiling analysis in patients with endometrial cancer and hyperplasia, and control patients. Conventional 2D gel electrophoresis, followed by a mass spectrometry approach with bioinformatics, including a network pathway analysis pipeline, was used to identify differentially expressed proteins and associated metabolic pathways between the study groups. Thirty-six patients (twelve with endometrial cancer, twelve with hyperplasia, and twelve controls) were enrolled in this study. The mean age of the participants was 46–75 years. Eighty-seven proteins were significantly differentially expressed between the study groups, of which fifty-three were significantly differentially regulated (twenty-eight upregulated and twenty-five downregulated) in the tissue samples of EC patients compared to the control (Ctrl). Furthermore, 26 proteins were significantly dysregulated (8 upregulated and 18 downregulated) in tissue samples of hyperplasia (HY) patients compared to Ctrl. Thirty-two proteins (nineteen upregulated and thirteen downregulated) including desmin, peptidyl prolyl cis-trans isomerase A, and zinc finger protein 844 were downregulated in the EC group compared to the HY group. Additionally, fructose bisphosphate aldolase A, alpha enolase, and keratin type 1 cytoskeletal 10 were upregulated in the EC group compared to those in the HY group. The proteins identified in this study were known to regulate cellular processes (36%), followed by biological regulation (16%). Ingenuity pathway analysis found that proteins that are differentially expressed between EC and HY are linked to AKT, ACTA2, and other signaling pathways. The panels of protein markers identified in this study could be used as potential biomarkers for distinguishing between EC and HY and early diagnosis and progression of EC from hyperplasia and normal patients.

miR-106b-5p contributes to the lung metastasis of breast cancer via targeting CNN1 and regulating Rho/ROCK1 pathway

OBJECTIVES

Breast cancer has been the second most prevalent and fatal malignancy due to its frequent metastasis to other organs. We aim to study the effects of a key miRNA-mRNA signaling in breast cancer.

RESULTS

CNN1 was identified as the key gene in breast cancer by the bioinformatics analysis, and the downregulation of CNN1 in breast cancer tissues and cell lines was observed. Upregulating CNN1 inhibited cell survival, migration, invasion, and adhesion, but enhanced cell apoptosis. miR-106b-5p not only bound to CNN1 mRNA 3'UTR, but also promoted lung metastasis in vivo. Besides, the miR-106b-5p mimic enhanced breast cancer canceration by targeting CNN1 and activating Rho/ROCK1 signaling pathway.

CONCLUSION

Overall, our results proved that miR-106b-5p promoted the metastasis of breast cancer by suppressing CNN1 and activating Rho/ROCK1 pathway.

METHODS

Bioinformatics analysis was performed to select the key gene in breast cancer. The overexpression and knockdown of Calponin 1 (CNN1) in breast cancer cell lines were performed to conduct cell viability, migrating, invasion, proliferation, adhesion, and apoptosis experiments. To identify the role of miR-106b-5p and Rho/ROCK1 in CNN1-induced breast cancer, a dual-luciferase assay, tumor lung metastasis assay, transcript half-life assay, and Rho/ROCK1 inhibition assay were performed.

Expression of Myoepithelial Markers in Mammary Carcinomas of 119 Pet Rabbits

Simple Summary

Mammary cancer is a serious health issue in pet rabbits; prognostic factors are unknown. In a normal mammary gland, glandular secretory cells are surrounded by a single continuous layer of myoepithelial cells. In non-invasive mammary carcinomas, tumor cells are delineated by an intact myoepithelial layer, which is gradually lost to invasive carcinomas. The main aim of this study was to determine in rabbit mammary carcinomas (n = 119) the expression of myoepithelial markers that have prognostic significance in human cancer. Results show that all cases contained some retained myoepithelial cells. In 93% of the tumors, neoplastic cells expressed the myoepithelial marker calponin. There was a statistically significant association between higher percentages of calponin-containing cancer cells and histological features indicative of a better tumor differentiation, i.e., a lower proliferation of tumor cells, an increased percentage of tubular growth within the tumor, and a lower tumor grade, respectively. These results suggest that rabbit mammary carcinomas develop from progression of non-invasive cancer forms, and that calponin expression in cancer cells likely represents a favorable prognostic factor. The latter hypothesis has to be confirmed in long-term follow-up studies.

Abstract

Most mammary tumors in pet rabbits are carcinomas; prognostic factors are unknown. The aim of this study on rabbit mammary carcinomas was to determine the expression of myoepithelial markers that have a prognostic relevance in human cancers. Mammary carcinomas (n = 119) of female or female-spayed pet rabbits were immunostained for cytokeratin AE1/AE3, vimentin, smooth muscle actin (SMA), and calponin; and percentages of non-neoplastic myoepithelial cells (ME cells) and calponin-positive neoplastic cells were determined. Using statistical analysis, data were correlated with the age of the rabbits and histological tumor characteristics. All carcinomas contained retained spindle-shaped ME, while 115 also contained hypertrophic ME (HME). A statistically significant relationship existed between a higher age and an increase in HME. In 111 carcinomas (93%), tumor cells expressed calponin. There was a significant correlation between higher percentages of calponin-positive tumor cells and a lower mitotic count, an increased percentage of tubular growth, and a lower grading score, respectively. Data suggest that pet rabbit mammary carcinomas develop from progression of in situ cancer and that the extent of calponin expression in tumor cells influences their biological behavior. These results provide the basis for a long-term follow-up on the prognostic significance of calponin expression in mammary cancer cells.

Loss of calponin h1 confers anoikis resistance and tumor progression in the development of high-grade serous carcinoma originating from the fallopian tube epithelium

Increasing evidence indicates that ovarian high-grade serous carcinoma (HGSC) originates from the fallopian tube epithelium and metastasizes to the ovary as the secondary site. A working hypothesis is that detached tubal HGSC cells survive anoikis and implant on the ovary. In this study, we found that downregulation of calponin h1 (CNN1) is necessary for the anoikis survival and cell transformation. CNN1 was progressively downregulated in cells and tissues representing different stages of HGSC development from fallopian tube epithelium (FTE). Knock down of CNN1 in immortalized human FTE cells conferred gains of resistance to anoikis and transformation phenotypes including anchorage independent growth (AIG) and xenograft tumorigenesis in NSG mice. Conversely, overexpression of CNN1 in RAS-transformed FTE cells resulted in an almost complete loss of AIG and tumorigenesis. Besides, there was a dramatic change of cell morphology from a polygonal, raised appearance to a round and flattened one. Increase in cell adhesion to laminin and collagen, and reduction in cell motility, anoikis resistance and invasiveness were also observed. A microarray analysis revealed upregulation of genes involved in cytoskeleton stabilization and signal transduction, and downregulation of genes involved in cytokine and chemokine activities. The study disclosed multiple tumor suppressor roles of CNN1 in the development of HGSC from the fallopian tube, and loss of CNN1 expression is crucial for its metastasis to a new site.

Cloning and mineralization-related functions of the calponin gene in Chlamys farreri

Calponin is a widely distributed protein which is associated with the bio-mineralization process in vertebrates. Recently, a new type of calponin has been found in shellfish; the present study aimed to determine if this gene in shellfish functions in bio-mineralization, one of the most important processes in a mollusk's growth. We chose Chlamys farreri, a seashell species with great economic value, as the object of the study and obtained its full-length cDNA to study the function of calponin by gene expression analysis, shell notching experiment and RNA interference assays. Calponin in C. farreri is a basic protein that is highly conserved among mollusk species. Except for high expression in the adductor muscle and foot, which correlated with its function of regulating muscle contraction, the calponin gene was expressed more in the mantle than in other tissues. The expression of the gene was induced by shell notching and an RNA interference assay showed that inhibition of calponin expression caused the growth of irregular mineral crystals on the shell. Further analysis indicated that calponin might function by regulating the expression of other mineralization-related genes. Calponin is a mineralization-related protein in C. farreri that might influence mineral crystal growth by affecting the expressions of other proteins, such as matrix proteins and mineralization-regulating proteins.

Calponin isoforms CNN1, CNN2 and CNN3: Regulators for actin cytoskeleton functions in smooth muscle and non-muscle cells

Calponin is an actin filament-associated regulatory protein expressed in smooth muscle and many types of non-muscle cells. Three homologous genes, CNN1, CNN2 and CNN3, encoding calponin isoforms 1, 2, and 3, respectively, are present in vertebrate species. All three calponin isoforms are actin-binding proteins with functions in inhibiting actin-activated myosin ATPase and stabilizing the actin cytoskeleton, while each isoform executes different physiological roles based on their cell type-specific expressions. Calponin 1 is specifically expressed in smooth muscle cells and plays a role in fine-tuning smooth muscle contractility. Calponin 2 is expressed in both smooth muscle and non-muscle cells and regulates multiple actin cytoskeleton-based functions. Calponin 3 participates in actin cytoskeleton-based activities in embryonic development and myogenesis. Phosphorylation has been extensively studied for the regulation of calponin functions. Cytoskeleton tension regulates the transcription of CNN2 gene and the degradation of calponin 2 protein. This review summarizes our knowledge learned from studies over the past three decades, focusing on the evolutionary lineage of calponin isoform genes, their tissue- and cell type-specific expressions, structure-function relationships, and mechanoregulation.

Overexpression of H1 calponin in osteoblast lineage cells leads to a decrease in bone mass by disrupting osteoblast function and promoting osteoclast formation

H1 calponin (CNN1) is known as a smooth muscle-specific, actin-binding protein which regulates smooth muscle contractive activity. Although previous studies have shown that CNN1 has effect on bone, the mechanism is not well defined. To investigate the role of CNN1 in maintaining bone homeostasis, we generated transgenic mice overexpressing Cnn1 under the control of the osteoblast-specific 3.6-kb Col1a1 promoter. Col1a1-Cnn1 transgenic mice showed delayed bone formation at embryonic stage and decreased bone mass at adult stage. Morphology analyses showed reduced trabecular number, thickness and defects in bone formation. The proliferation and migration of osteoblasts were decreased in Col1a1-Cnn1 mice due to alterations in cytoskeleton. The early osteoblast differentiation of Col1a1-Cnn1 mice was increased, but the late stage differentiation and mineralization of osteoblasts derived from Col1a1-Cnn1 mice were significantly decreased. In addition to impaired bone formation, the decreased bone mass was also associated with enhanced osteoclastogenesis. Tartrate-resistant acid phosphatase (TRAP) staining revealed increased osteoclast numbers in tibias of 2-month-old Col1a1-Cnn1 mice, and increased numbers of osteoclasts co-cultured with Col1a1-Cnn1 osteoblasts. The ratio of RANKL to OPG was significantly increased in Col1a1-Cnn1 osteoblasts. These findings reveal a novel function of CNN1 in maintaining bone homeostasis by coupling bone formation to bone resorption.

MicroRNA miR-196a controls melanoma-associated genes by regulating HOX-C8 expression

Resulting from a screening for microRNAs differentially regulated in melanocytes and melanoma cells, we found expression of miR-196a to be significantly down-regulated in malignant melanoma cell lines and tissue samples. As it was stated before that miR-196a might negatively regulate expression of the transcription factor HOX-C8, we analyzed HOX-C8 levels in NHEMs and melanoma cells and found a strong up-regulation of HOX-C8 expression in malignant melanoma cell lines and tissue samples compared with melanocytes. Several HOX-C8 target genes are known to be involved in processes such as oncogenesis, cell adhesion, proliferation and apoptosis. We, therefore, aimed to further investigate a potential "miR-196a → HOX-C8 → HOX-C8 target gene" relationship. Stable transfection with an miR-196a expression plasmid led to strong down-regulation of HOX-C8 expression in melanoma cells. Luciferase assays using reporter plasmids containing different fragments of the HOX-C8 3'UTR confirmed direct interactions of miR-196a with the HOX-C8 mRNA. Focusing on target genes of HOX-C8, which might play an important role in melanomagenesis, we identified three genes (cadherin-11, calponin-1 and osteopontin) that are up- or down-regulated, respectively, by altered HOX-C8 expression in miR-196a expressing cell clones and are thus indirectly regulated by this microRNA. As those target genes are closely related to important cellular mechanisms such as cell adhesion, cytoskeleton remodeling, tumor formation and invasive behavior of tumor cells, altered miR-196a expression exerts strong effects contributing to tumor cell transformation and formation and progression of malignant melanoma. This fact is underlined by a strongly reduced invasive behavior of melanoma cells re-expressing miR-196a in vitro.

Calponin expression in laryngeal myoepithelial carcinoma and its prognostic implications: a case report and literature review

A case report of laryngeal myoepithelial carcinoma (MEC) is presented and the literature concerning prognostic factors in MEC is reviewed. A 61-year old man was admitted to hospital with hoarseness and progressive dyspnoea. On examination, both vocal cords were fixed in the midline with a glottic fissure of only 3 mm. No tumour was seen, but the subglottis was not completely visible. A computed tomography scan showed a soft mass below the right vocal cord obstructing two-thirds of the larynx. On suspension laryngoscopy, a dull mass (1.5 x 1.5 cm) was seen below the right vocal cord, which was malignant on frozen biopsy. A total laryngectomy was performed and the patient received radiotherapy. He died of recurrence 25 months later. The tumour was positive for cytokeratin 14, S-100 protein and calponin. MEC of the larynx is extremely rare. The clinical behaviour of MEC is variable and prognostic factors have been poorly analysed. Calponin expression may be a prognostic factor, but other factors also affect the outcome in MEC.

Calponin in non-muscle cells

Calponin is an actin filament-associated regulatory protein expressed in smooth muscle and non-muscle cells. Calponin is an inhibitor of the actin-activated myosin ATPase. Three isoforms of calponin have been found in the vertebrates. Whereas the role of calponin in regulating smooth muscle contractility has been extensively investigated, the function and regulation of calponin in non-muscle cells is much less understood. Based on recent progresses in the field, this review focuses on the studies of calponin in non-muscle cells, especially its regulation by cytoskeleton tension and function in cell motility. The ongoing research has demonstrated that calponin plays a regulatory role in non-muscle cell motility. Therefore, non-muscle calponin is an attractive target for the control of cell proliferation, migration and phagocytosis, and the treatment of cancer metastasis.

Reduction of Calponin h1 expression in human colon cancer blood vessels

AIMS

Calponin h1 (CN) is a differentiation marker of smooth muscle cells that has been reported to be down-regulated in the blood vessels of several human tumors. In this study, we examined CN expression in blood vessels in relation to the clinical and pathological features of colon cancer tissue samples.

METHODS

Fifty-six patients who had undergone colectomy for colon cancer were examined. To assess patients' disease-free survival, those who had metastasis at the time of surgical operation were excluded. Immunohistochemistry was performed by the indirect immunoperoxidase method, using serial sections made from formalin fixed and paraffin embedded tissue blocks.

RESULTS

We found that the expression of vascular CN in the peripheral region of colon cancer tissues was significantly reduced in association with tumor progression, lymphatic invasion, vascular invasion and recurrence. This reduction of CN indicated not only a decrease of pericytes and/or smooth muscle cells in tumor vessels, but also the immaturity of those cells, since CN down-regulation occurred even in alpha-smooth muscle actin-positive cells. The down-regulation of CN in vessels in the peripheral region of tumor tissues was inversely associated with the expression of VEGF (vascular endothelial growth factor), seemingly advantageous to angiogenesis.

CONCLUSION

The down-regulation of CN expression in colon cancer vasculature evaluated by immunohistochemistry may be useful in conjunction with conventional staging procedures to predict more reliable outcome and to select therapeutic treatment.

Adenovirus-mediated calponin h1 gene therapy directed against peritoneal dissemination of ovarian cancer: bifunctional therapeutic effects on peritoneal cell layer and cancer cells

PURPOSE

Calponin h1 (CNh1), one of the family of actin-binding proteins, stabilizes the filaments of actin and modulates various cellular biological phenotypes. Recent studies revealed the close correlation between the invasive tumor spread and the reduced expression of CNh1 and alpha-smooth muscle actin in the surrounding stromal cells. The purpose of this study is to evaluate the efficacy of i.p. CNh1 gene therapy against peritoneal dissemination of ovarian cancer.

EXPERIMENTAL DESIGN

We used an adenoviral vector to induce the CNh1 gene into peritoneal cells and ovarian cancer cells as a means of enhancing or inducing the expression of alpha-smooth muscle actin as well as CNh1. The efficacy of gene transfer was examined by in vitro cell culture and in vivo animal experiments.

RESULTS

The formation of longer and thicker actin fibers was observed in each transfected cell line, and the localization of these fibers coincided with that of externally transducted CNh1. With respect to changes in cell behavior, the CNh1-transfected peritoneal cells acquired an ability to resist ovarian cancer-induced shrinkage in cell shape; thus, cancer cell invasion through the monolayer of peritoneal cells was inhibited. In addition, CNh1-transfected ovarian cancer cells showed suppressed anchorage-independent growth and invasiveness, the latter of which accompanied impaired cell motility. The concomitant CNh1 transfection into both peritoneal cells and ovarian cancer cells produced an additive inhibitory effect with respect to cancer cell invasion through the peritoneal cell monolayer. By in vivo experiments designed to treat nude mice that had been i.p. inoculated with ovarian cancer cells, we found that the i.p. injected CNh1 adenovirus successfully blocked cancer-induced morphologic changes in peritoneal cell surface and significantly prolonged the survival time of tumor-bearing mice. Moreover, CNh1 adenovirus could successfully enhance the therapeutic effect of an anticancer drug without increase in side effects.

CONCLUSIONS

Thus, CNh1 gene therapy against peritoneal dissemination of ovarian cancer is bifunctionally effective (i.e., through inhibitory effects on the infected peritoneal cell layers that suppress cancer invasion and through direct antitumor effects against invasion and growth properties of cancer cells).

Suppression of cancer phenotypes through a multifunctional actin-binding protein, calponin, that attacks cancer cells and simultaneously protects the host from invasion

Quantitative and/or qualitative alteration of actin cytoskeletal molecules, involved in the regulation of cellular dynamic functions, should be intimately related with cancer phenotypes. Based on several lines of experimental evidence from our group, and others, this report proposes a strategy to simultaneously attack cancer cells and protect the host from cancer invasion, with one molecule. Calponin h1, an actin-stabilizing protein that is also intimately related to signal transduction, is very often suppressed in vascular smooth muscle cells of malignant human tumors and in mesothelial cells by coexisting cancer cells. We generated mice deficient for calponin h1, exhibiting fragility in blood vessels and peritoneal membranes. Hematogenous cancer metastasis occurred more easily in the calponin h1-deficient mice than in wild-type mice, and the peritoneal dissemination was extremely enhanced. The fragility was rescued by the exogenous introduction of the calponin h1 gene into mesothelial cells of the peritoneum. Furthermore, calponin h1 gene transfer into several transformed cell lines resulted in a suppression of malignancy. The peritoneal dissemination of intraperitoneally-injected B16-F10 cells was suppressed by the calponin h1 gene, given to target both cancer cells and the mesothelial cells of the host. The multifunctional nature of the molecule, as a machinery player of cytoskeleton and mediator of signal transduction, probably resulted in a favorable recipient-discriminating effect on cancerous and normal cells. Thus, we believe that if we use adequate multifunctional molecules for therapy, it is possible to simultaneously suppress cancer phenotypes and protect normal cells from the attack of cancer cells.

Matrix-degrading podosomes in smooth muscle cells

Activation of protein kinase C by phorbol esters triggers the remodelling of the actin cytoskeleton and the formation of podosomes in smooth muscle cells (SMCs). Regional control of actin dynamics at specialised microdomains results in a local reduction in contractile forces. The molecular basis for this local inhibition of contractility includes the clustering of cortactin during podosome formation (which precedes the rapid, local dispersion of myosin, tropomyosin and h1 calponin), and the specific recruitment of 110-kDa actin filament-associated protein (AFAP-110) and 190-kDa Rho-specific GTPase-activating protein (p190RhoGAP) to the microdomains. Podosome formation also correlates with cell polarisation, the induction of cell motility, and local degradation of the extracellular matrix. These findings may provide explanations for the complex mechanisms underlying SMC invasion in the course of the development of atherosclerotic lesions and restenosis, and support the concept that matrix degradation and the concomitant engagement of the molecular machinery initiating actin-based cell motility drive tissue invasion in smooth muscle.

Loss of calponin h1 in renal angiomyolipoma correlates with aggressive clinical behavior

OBJECTIVES

To investigate whether any immunohistochemical differences exist between two types of renal angiomyolipomas (AMLs). Renal AMLs are generally considered to be benign in nature. However, a few of these tumors have been reported to involve other organs.

METHODS

Tissue specimens from 3 cases of clinically aggressive and 9 cases of clinically indolent renal AMLs were examined histologically and immunohistochemically using antibodies against calponin h1 and alpha-smooth muscle actin. Immunostaining was evaluated semiqualitatively as no staining to strong staining.

RESULTS

The tumor cells in the myomatous component of the aggressive type did not show any reaction to the antibody to calponin h1 protein, but they showed strong immunoreactions with the antibody to the alpha-smooth muscle actin antigen. All cases of the nonaggressive AMLs demonstrated strong immunoreactions with both antibodies used.

CONCLUSIONS

Our initial results in a small series of cases suggest a potential molecular difference between the aggressive and nonaggressive type of AMLs. Loss of calponin h1 from the tumor cells of the aggressive type might be related to their pathologically invasive features, and this aggressive type might be categorized into an intermediate type between the benign and malignant types.

Invasion of normal human fibroblasts induced by v-Fos is independent of proliferation, immortalization, and the tumor suppressors p16INK4a and p53

Invasion is generally perceived to be a late event during the progression of human cancer, but to date there are no consistent reports of alterations specifically associated with malignant conversion. We provide evidence that the v-Fos oncogene induces changes in gene expression that render noninvasive normal human diploid fibroblasts highly invasive, without inducing changes in growth factor requirements or anchorage dependence for proliferation. Furthermore, v-Fos-stimulated invasion is independent of the pRb/p16(INK4a) and p53 tumor suppressor pathways and telomerase. We have performed microarray analysis using Affymetrix GeneChips, and the gene expression profile of v-Fos transformed cells supports its role in the regulation of invasion, independent from proliferation. We also demonstrate that invasion, but not proliferation, is dependent on the activity of the up-regulated epidermal growth factor receptor. Taken together, these results indicate that AP-1-directed invasion could precede deregulated proliferation during tumorigenesis and that sustained activation of AP-1 could be the epigenetic event required for conversion of a benign tumor into a malignant one, thereby explaining why many malignant human tumors present without an obvious premalignant hyperproliferative dysplastic lesion.

Calponin h1 expression in renal tumor vessels: correlations with multiple pathological factors of renal cell carcinoma

PURPOSE

We determined whether the architecture of renal tumor vessels is immunohistochemically different from that of normal renal vessels and related to the various pathological factors that affect prognosis of renal cell carcinoma (RCC).

MATERIALS AND METHODS

A total of 52 cases of primary RCC were selected. Tissues from radical nephrectomy specimens were stained with antibody to alpha-smooth muscle actin (alpha-SMA) and calponin h1. Immunostaining was evaluated semiqualitatively as 0-no staining to 3+-strong staining. Tumor cell proliferation was observed using proliferating marker Ki-67. Data were statistically compared with pathological factors, such as tumor size, histological pattern, growth pattern, cell type, nuclear grade, pathological stage and presence or absence of venous invasion.

RESULTS

In normal renal tissues smooth muscle cells of the blood vessels showed strong immunoreactions with antibody to calponin h1 and alpha-SMA. Although alpha-SMA antibody showed similar strong immunoreactions in all types of renal tumor vessels, we observed qualitative alterations in the expression of calponin h1 in different types of RCCs. Strong to moderate immunoreactions with calponin h1 were observed in tumors with expansive growth and an alveolar pattern. Small tumors without venous invasion and chromophobe cell carcinomas also showed strong to moderate expression of calponin h1. Weak or absent expression of calponin h1 was observed significantly in infiltrating tumors, sarcomatous type, large, high grade and high stage tumors associated with significantly higher proliferating indexes.

CONCLUSIONS

Our results strongly suggest that the renal tumor vessels are immunohistochemically different from normal renal vessels in respect to calponin h1 expression. We speculate that due to the decrease in or absence of calponin h1 tumor vessels do not develop adequate maturity to maintain vascular integrity. In addition, the distribution of calponin h1 significantly correlated with multiple pathological factors of RCC. Therefore, calponin h1 expression in renal tumor vessels could be a new, important pathological factor in RCC.

The role of calponin in the gene profile of metastatic cells: inhibition of metastatic cell motility by multiple calponin repeats

Metastasis of diseased cells is the basic event leading to death in individuals with cancer. Establishment of metastasis requires that tumour cells migrate from the site of the primary tumour into the circulation system, escape from the vasculature and form secondary tumours at novel sites. These processes depend to a large degree on cytoskeletal remodeling. We show here that multiple copies of the short actin-binding module CLIK(23) from human or Caenorhabditis elegans calponin proteins effectively inhibit cell motility on two dimensional matrices and suppress soft agar colony formation of metastatic melanoma and adenocarcinoma cells of murine and human origin. Ectopic expression of CLIK(23) modules for 30 days results in the formation of multinucleated cells. The repeat displays true modular behaviour, resulting in increased cytoskeletal effects in direct correlation with the increase in number of modules. Our results demonstrate that the role of calponin in the signature profile of metastasising cells is that of a mechanical stabiliser of the actin cytoskeleton, which interferes with actin turnover by binding at a unique interface along the actin filament.

Podosome formation in cultured A7r5 vascular smooth muscle cells requires Arp2/3-dependent de-novo actin polymerization at discrete microdomains

Phorbol ester triggers the conversion of focal adhesions into podosomes in A7r5 smooth muscle cells. Here we followed the dynamics of podosome formation using dual fluorescence live video and confocal microscopy, as well as interference reflection and evanescent wave microscopy. We show that podosomes form at the outer region of stress fiber bundles, at specialized sites where they are embedded in adhesion plaques at the basal surface of the plasma membrane, and that cortactin resides constitutively at these microdomains. We further demonstrate that the formation of podosomes requires Arp2/3-dependent actin polymerization at the stress fiber-focal adhesion interface. Concentration of Arp2/3 coincides with podosome formation and precedes the engagement of SM22 and alpha-actinin, while the focal adhesion components zyxin and vinculin redistribute only at later stages of podosome development. We thus suggest that the genesis of podosomes includes two steps, one requiring the early de novo polymerization of actin filaments, and a second, late phase characterized by the recruitment of focal adhesion components. Moreover, we provide evidence for the existence of an as yet unidentified region in close proximity to the focal adhesion-stress fiber interface, which marks the site of actin cytoskeleton remodeling and is a novel site of Arp2/3-dependent F-actin polymerization.

Suppression of peritoneal dissemination through protecting mesothelial cells from retraction by cancer cells

In a previous study, we demonstrated that calponin h1 suppressed tumor growth of transformed cells and that the peritonitis carcinomatosa induced by mouse B16-F10 melanoma (F10) cells was more extensive in calponin h1-deficient (CN(-/-)) mice with fragility of mesothelial (MS) cells than in their calponin h1-wild (CN(+/+)) counterparts. In our study, we assessed the therapeutic effect of calponin h1 on peritoneal dissemination. F10 cells were overlaid on the cultured CN(+/+) or CN(-/-) MS cells and the effect of calponin h1 on retraction of MS cells was evaluated. Then, an adenoviral vector with the calponin h1 gene (AdGFP-CN) inserted was constructed and was applied to CN(-/-) MS cells or CN(-/-) mouse peritoneum to investigate its suppressive effect on the peritoneal dissemination caused by F10 cells. Greater retraction and invasion of F10 cells were observed in CN(-/-) MS than in CN(+/+) cells in vitro, while down-regulation of calponin h1 was observed in CN(+/+) MS cells prior to the invasion of F10 cells. Infecting CN(-/-) MS cells with AdGFP-CN prevented their retraction and the invasion of F10 cells. Peritoneal dissemination was prominently suppressed in AdGFP-CN-infected CN(-/-) mice, and the survival of those mice was significantly prolonged. Thus, calponin h1 functioned to protect host MS cells from the invasion of F10 cells.

Differential gene expression in pubococcygeus muscle from patients with pelvic organ prolapse

OBJECTIVE

This study was undertaken to compare differential gene expression in the pubococcygeus muscle in patients with pelvic organ prolapse and controls.

STUDY DESIGN

We performed microarray analysis on individual pubococcygeus muscle biopsy specimens from five patients with stage III or IV pelvic organ prolapse and five control subjects without prolapse. This study received full Institutional Review Board approval. Total RNA was extracted, purified, and probed on the Human Genome U95A Array for each individual sample. RNA from patients and controls was not pooled. For microarray analysis, 7 microg of total RNA was used to synthesize complementary DNA that was then biotinylated. Arrays were hybridized for 16 hours in the GeneChip Fluidics Station 400 and were washed and scanned with the Hewlett-Packard GeneArray Scanner. Affymetrix GeneChip 5.0 software was used for scanning and data analysis.

RESULTS

Of the 12626 total genes compared, 257 genes were more than 2-fold underexpressed, 20 genes were more than 5-fold underexpressed, and 3 genes were more than 10-fold underexpressed in patients with pelvic organ prolapse compared with control subjects. Myosin-binding protein H was 24.7 times underexpressed in patients with prolapse (normalized signal intensity [NSI]: 0.46 [0.2-0.6]) compared with controls (NSI: 11.4 [0.2-31.3]). Skeletal muscle myosin heavy polypeptide 3 was 17.4 times underexpressed in patients with prolapse (NSI: 0.85 [0.7-0.9]) compared with controls (NSI: 14.8 [1.5-38.3]). Of the 12,626 genes compared, 479 genes were more than 2-fold overexpressed, 18 genes were more than 5-fold overexpressed, and 2 genes were more than 10-fold overexpressed in patients with pelvic organ prolapse compared with controls. Many of these overexpressed genes were related to actin and myosin proteins. Smooth muscle myosin heavy chain was 11.8 times overexpressed in patients (NSI: 5.21 [0.25-22.71]) compared with controls (NSI 0.44 [0.11-0.71]). Myosin light-chain kinase was 5.8 times overexpressed in patients (NSI: 7.9 [0.5-36.1]) compared with controls (NSI: 1.37 [0.38-1.8]). Extracellular matrix proteins were also differentially regulated. Cartilage oligomeric matrix protein precursor was found to be 6.0 times underexpressed, whereas tenascin-C (hexabrachion) was 5.1 times overexpressed in prolapse patients.

CONCLUSION

These data suggest that the differences between patients with advanced pelvic organ prolapse and controls may be related to differential gene expression of structural proteins that are related to actin and myosin as well as extracellular matrix proteins in the pubococcygeus muscle. Studies are ongoing to confirm these findings and to further characterize the role of these genes in prolapse.

Reduced expression of actin-binding proteins, h-caldesmon and calponin h1, in the vascular smooth muscle inside melanoma lesions: an adverse prognostic factor for malignant melanoma

BACKGROUND

The structural integrity of the blood vessels such as small arteries and veins is studied less frequently in malignant tumours than is angiogenesis. Objectives To clarify the characteristics of small arteries and small veins of melanoma lesions.

METHODS

We immunohistochemically investigated various types of melanocytic tumours using antibodies specific for endothelial and vascular smooth muscle cells, and analysed the relationship between the expression of these molecules in the blood vessels and the biological characteristics of the tumours. Formalin-fixed, paraffin-embedded sections of 15 cases of benign melanocytic tumours and 64 cases of malignant melanomas were investigated.

RESULTS

Significant suppression of expression of h-caldesmon (h-CD) and calponin h1 (CNh1) was observed in the blood vessels of malignant melanomas compared with both benign melanocytic tumours and normal tissues. In particular, the level of h-CD expression was inversely correlated with the frequency of metastasis and positively correlated with the survival rate in patients with malignant melanoma.

CONCLUSIONS

These findings suggest that alterations of the tumour vessels are an important factor for the prognosis of malignant melanoma, and that suppression of h-CD and CNh1 in the blood vessels in malignant melanoma reflects a structural fragility of the vessels, leading to their easy penetration by tumour cells. Defective expression of these molecules is likely to be an important marker for metastatic potential and for poor prognosis of melanoma.

Calponin h1 suppresses tumor growth of Src-induced transformed 3Y1 cells in association with a decrease in angiogenesis

Calponin h1 (CNh1) is a basic actin-binding protein that is abundantly expressed in smooth muscle cells and involved in smooth muscle contraction by inhibiting actomyosin MgATPase. In recent studies, CNh1 was noted to suppress cell proliferation and tumorigenicity in leiomyosarcoma and tumor growth in fibrosarcoma cell lines. To further investigate the function of CNh1 as a tumor suppressor, we transfected the human CNh1 gene into a v-src-transformed rat fibroblast cell line SR-3Y1. The volume of the tumors derived from one randomly selected CNh1-transfectant (C1) in nude mice was reduced to 34.1% of that from a randomly selected vector transfectant (V1). A similar tendency was observed in another independent pair (C2, V2). Pathological analysis showed a significant decrease in the number of mitotic cells in the CNh1-transfectants. Further, a marked reduction in the number of vessels in the CNh1-transfectant was observed. DNA synthesis under conditions without serum was significantly reduced in the CNh1-transfectant (C1) compared with the control transfectant (V1), while no significant difference was seen in the cellular growth in the presence of 10% serum. A slight but significant reduction in in vitro cellular motility in the CNh1-transfectant was also observed. While the suppression of growth potential and cell motility by CNh1 transfer was significant but partial, a marked reduction in vascular endothelial growth factor (VEGF) mRNA and the secretion of VEGF protein was observed in the CNh1-transfectant. These results suggest that CNh1 plays a role as tumor suppressor in SR-3Y1 mainly by decreasing VEGF expression and angiogenesis in vivo and partially through reducing cellular proliferative potential and cell motility.