Human malignant melanoma cells release a factor that inhibits the expression of smooth muscle alpha-actin

Aberrant Expression of Immunohistochemical Markers in Malignant Melanoma: A Review

Immunohistochemical stains are increasingly used to aid in the diagnosis of malignant melanoma, especially when the differentiation of the tumor is unclear based on examination with hematoxylin and eosin. However, aberrant expression of non-melanocytic markers has been reported in melanomas, which can sometimes be further complicated by the loss of conventional melanocytic markers. This review aims to summarize available data regarding unusual staining patterns in primary and metastatic malignant melanoma. It also raises awareness of the potential pitfalls and highlights the importance of appropriate use and interpretation of broad immunohistochemical markers in the context of clinical and histopathologic findings to facilitate the diagnosis of atypical cases of malignant melanoma.

Contextualizing the Genes Altered in Bladder Neoplasms in Pediatric andTeen Patients Allows Identifying Two Main Classes of Biological ProcessesInvolved and New Potential Therapeutic Targets

Research on bladder neoplasms in pediatric and teen patients (BNPTP) has described 21 genes, which are variously involved in this disease and are mostly responsible for deregulated cell proliferation. However, due to the limited number of publications on this subject, it is still unclear what type of relationships there are among these genes and which are the chances that, while having different molecular functions, they i) act as downstream effector genes of well-known pro- or anti- proliferative stimuli and/or interplay with biochemical pathways having oncological relevance or ii) are specific and, possibly, early biomarkers of these pathologies. A Gene Ontology (GO)-based analysis showed that these 21 genes are involved in biological processes, which can be split into two main classes: cell regulation-based and differentiation/development-based. In order to understand the involvement/overlapping with main cancer-related pathways, we performed a meta-analysis dependent on the 189 oncogenic signatures of the Molecular Signatures Database (OSMSD) curated by the Broad Institute. We generated a binary matrix with 53 gene signatures having at least one hit; this analysis i) suggests that some genes of the original list show inconsistencies and might need to be experimentally re- assessed or evaluated as biomarkers (in particular, ACTA2) and ii) allows hypothesizing that important (proto)oncogenes (E2F3, ERBB2/HER2, CCND1, WNT1, and YAP1) and (putative) tumor suppressors (BRCA1, RBBP8/CTIP, and RB1-RBL2/p130) may participate in the onset of this disease or worsen the observed phenotype, thus expanding the list of possible molecular targets for the treatment of BNPTP.

Malignant melanoma and its stromal nonimmune microecosystem

In recent years, rapid advances were reached in the understanding of a series of biologic signals influencing cutaneous malignant melanoma (CMM) cells. CMM is in close contact with a peculiar dermal extracellular matrix (ECM). Stromal cells store and release various structural ECM components. The impact on CMM growth and progression is mediated through strong and long-lasting effects of ECM products. This paper summarizes some peculiar aspects of the peri-CMM stroma showing intracytoplasmic loads in Factor XIIIa, CD34, versican, and α (IV) collagen chains. The restricted peri-CMM skin territory exhibiting such changes corresponds to the area showing neoangiogenesis and extravascular unicellular metastatic spread. The latter inconspicuous migratory CMM cells possibly correspond to CMM stem cells or to CMM cells with aberrant HOX gene expression. Their presence is associated with an increased risk for metastases in the regional sentinel lymph nodes. In conclusion, the CMM-stroma connection appears crucial to the growth regulation, invasiveness and initial metastatic spread of CMM cells. Although much remains to be learned in this field, the active intervention of the peri-CMM stroma is likely involved in the inconspicuous early metastatic migration of CMM cells.

Identification of TFG (TRK-fused gene) as a putative metastatic melanoma tumor suppressor gene

High density SNP arrays can be used to identify DNA copy number changes in tumors such as homozygous deletions of tumor suppressor genes and focal amplifications of oncogenes. Illumina Human CNV370 Bead chip arrays were used to assess the genome for unbalanced chromosomal events occurring in 39 cell lines derived from stage III metastatic melanomas. A number of genes previously recognized to have an important role in the development and progression of melanoma were identified including homozygous deletions of CDKN2A (13 of 39 samples), CDKN2B (10 of 39), PTEN (3 of 39), PTPRD (3 of 39), TP53 (1 of 39), and amplifications of CCND1 (2 of 39), MITF (2 of 39), MDM2 (1 of 39), and NRAS (1 of 39). In addition, a number of focal homozygous deletions potentially targeting novel melanoma tumor suppressor genes were identified. Because of their likely functional significance for melanoma progression, FAS, CH25H, BMPR1A, ACTA2, and TFG were investigated in a larger cohort of melanomas through sequencing. Nonsynonymous mutations were identified in BMPR1A (1 of 43), ACTA2 (3 of 43), and TFG (5 of 103). A number of potentially important mutation events occurred in TFG including the identification of a mini mutation "hotspot" at amino acid residue 380 (P380S and P380L) and the presence of multiple mutations in two melanomas. Mutations in TFG may have important clinical relevance for current therapeutic strategies to treat metastatic melanoma.

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.

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.

Vasoprotective VEGF as a candidate for prevention of recurrence of fibrotic diseases such as Dupuytren's contracture

Dupuytren's contracture is a disease caused by the proliferation of contractile, fibroblastic cells adjacent to the palmar fascia of the hand. Cellular proliferation is apparently related to similar 'fibroblast' proliferation in wound healing, but continues in the absence of wounding. I propose that this is a similar processes to that which happens in the vascular wall during vascular surgery, that the myofibroblasts are at least partially similar to smooth muscle cells in phenotype, and consequently that treatment with VEGF, either as protein or via gene therapy, which has proven successful in controlling aberrant, wounding-related cell proliferation in arterial grafting, may be valuable in preventing recurrence of Dupuytren's disease after surgery.

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.

Recent advances in melanoma research

Recent advancement in the research of malignant melanoma is reviewed. Among many gene alterations detected in human melanoma, defect of CDKN2A located at chromosome 9p21 seems to be most important in the earlier developmental phase, though significance of this gene in the evolution of melanoma in situ has not been confirmed yet. Deletions of PTEN/MMAC1 on 10q23.3 and AIM1 on 6q21 as well as mutations of ras gene are involved in the later progression stages of melanoma. Adhesion molecules relevant to development and progression of melanoma have been intensely investigated in recent years, revealing crucial roles of cadherins and alpha(v)beta(3) integrin in the biologic behaviors of melanoma cells. Melanoma is characterized by extremely high potential of developing metastases. Dynamic changes of matrix metalloproteinase activity during invasion and movement of melanoma cells may be a major concern in this field. Fragility of blood vessels in melanoma lesions is another important point related to hematogeneous metastases. Acral lentiginous melanoma is a unique subtype of melanoma, because, in contrast to other subtypes, ultraviolet irradiation is not a major factor in its development. Investigation of pathogenesis of acral lentiginous melanoma surely provides us with new information about mechanism of melanocyte transformation. Recent advances in the management of malignant melanoma are also briefly reviewed, such as biochemotherapy, immunotherapy, and gene therapy. Finally, the concept of molecular classification of melanoma by gene expression profile is introduced, which possibly enables us to give the tailor-made therapy for each melanoma patient in the near future.