From Melanocyte to Metastatic Malignant Melanoma

Malignant melanoma is one of the most aggressive malignancies in human and is responsible for almost 60% of lethal skin tumors. Its incidence has been increasing in white population in the past two decades. There is a complex interaction of environmental (exogenous) and endogenous, including genetic, risk factors in developing malignant melanoma. 8–12% of familial melanomas occur in a familial setting related to mutation of the CDKN2A gene that encodes p16. The aim of this is to briefly review the microanatomy and physiology of the melanocytes, epidemiology, risk factors, clinical presentation, historical classification and histopathology and, more in details, the most recent discoveries in biology and genetics of malignant melanoma. At the end, the final version of 2009 AJCC malignant melanoma staging and classification is presented

First report of coexistence of AmpC beta-lactamase genes in Klebsiella pneumoniae strains isolated from burn patients

Klebsiella spp. are among the most frequently isolated bacteria from burn wounds. These organisms are among the most important opportunistic pathogens, causing hospital-acquired and healthcare-associated infections worldwide. Limited information is available about prevalence of AmpC-producing Klebsiella pneumoniae from burn patients. Therefore, the aim of this study was to determine the characterization of AmpC beta-lactamase among K. pneumoniae isolated from burn patients. Samples were collected from wound specimens of patients with burn injury from a burn hospital in Tehran during 18 months (March 2015 to August 2016). For phenotypic detection of AmpC beta-lactamase, disk diffusion method with cefoxitin was used for screening, AmpC disk test and boronic acid inhibitor-based method were used as confirmatory tests. Polymerase chain reaction (PCR) was performed to screen all isolates with AmpC genes including ACCM, DHAM, EBCM, FOXM, MOXM, and CITM. Finally, PCR products were validated using sequencing. During this study, 102 isolates of K. pneumoniae were collected. Among these isolates, 52.9% suspected as AmpC producer by disk agar diffusion cefoxitin screening method. By confirmatory phenotypic methods, 19.6% of isolates considered as AmpC producer. Molecular analysis revealed 43.1% of cefoxitin-resistant isolates harbored at least one of the AmpC genes including CITM (22.5%), EBCM (21.5%), DHAM (7.8%), and FOXM (0.98%). In addition, 5.8% of isolates harbored two AmpC genes and 2.9% harbored three AmpC genes. In conclusion, K. pneumoniae is becoming a serious problem in burn patients. Accurate and precise methods and guidelines should be designed for detection of antibiotic-resistant mechanisms. Our data showed the high rate of AmpC beta-lactamase among K. pneumoniae isolated from burn patients, which limit the treatment options. Therefore, the results of this study can provide evidence to help for appropriate treatment of burn patients

Role of cysteine proteinases in IGF-1R turnover, invasion and metastasis

Clinical cancer treatment has focused on the use of cytotoxic agents and/or radiation therapy that target both tumor and normal cells. Consequently, current cancer treatments with chemotherapeutic agents are subject to limitations associated with high toxicity and resistance. The cysteine proteinases cathepsin B and L have been linked to the invasive steps during the metastatic process and could therefore provide new targets for drug development.The present work describes our results with a murine Lewis lung carcinoma model which consists of two cell lines, H-59 and M-27, with different patterns of metastasis in vivo. Using this model, we found that the cysteine proteinase inhibitor, E-64, significantly inhibited the invasive/metastatic properties of the liver colonising cell line, H-59 both in vitro and in vivo. Because IGF-1R was identified as a critical mediator of matrix metalloproteinase-2 (MMP-2) synthesis, invasion and metastasis in H-59 cells, the possibility that the cysteine proteinases interfered with receptor for type 1 insulin-like growth factor (IGF-1R) turnover thereby reducing invasion was subsequently investigated.To elucidate more specifically the role of cysteine proteinases in the process of liver metastasis, cathepsin L expression was inhibited in the H-59 cells by transfection with a plasmid vector expressing a 300 by cathepsin L cDNA fragment in the antisense orientation. To further investigate the link between IGF-1R expression levels and invasion in these cells, MMP-2 production and activity were investigated. In cathepsin L antisense transfected H-59 cells reduced MMP-2 levels and activity as compared to controls were observed. Together our results suggest that the cysteine proteinases, cathepsin L in particular may regulate the metastatic potential through a role in IGF-1R turnover. The present results provide evidence that metastatic carcinomas which utilize cysteine proteinases for invasion could potentially be responsive to antimetastatic treatment with cysteine proteinase inhibitors. (Abstract shortened by UMI.

Collagen Type XI Inhibits Lung Cancer-Associated Fibroblast Functions and Restrains the Integrin Binding Site Availability on Collagen Type I Matrix

The tumor microenvironment, including cancer-associated fibroblast (CAF), plays an active role in non-small cell lung cancer (NSCLC) development and progression. We previously reported that collagen type XI and integrin α11, a collagen receptor, were upregulated in NSCLC; the latter promotes tumor growth and metastasis. We here explored the role of collagen type XI in NSCLC stroma. We showed that the presence of collagen type XI in collagen type I matrices inhibits CAF-mediated collagen remodeling and cell migration. This resulted in the inhibition of CAF-dependent lung-tumor cell invasion. Among the collagen receptors expressed on CAF, we determined that DDR2 and integrin α2β1, but not integrin α11β1, mediated the high-affinity binding to collagen type XI. We further demonstrated that collagen type XI restrained the integrin binding site availability on collagen type I matrices, thus limiting cell interaction with collagen type I. As a consequence, CAFs failed to activate FAK, p38 and Akt one hour after they interacted with collagen type I/XI. We concluded that collagen type XI may have a competitive negative feedback role on the binding of collagen type I to its receptors

LOXL1 Is Regulated by Integrin α11 and Promotes Non-Small Cell Lung Cancer Tumorigenicity

Integrin α11, a stromal collagen receptor, promotes tumor growth and metastasis of non-small cell lung cancer (NSCLC) and is associated with the regulation of collagen stiffness in the tumor stroma. We have previously reported that lysyl oxidase like-1 (LOXL1), a matrix cross-linking enzyme, is down-regulated in integrin α11-deficient mice. In the present study, we investigated the relationship between LOXL1 and integrin α11, and the role of LOXL1 in NSCLC tumorigenicity. Our results show that the expression of LOXL1 and integrin α11 was correlated in three lung adenocarcinoma patient datasets and that integrin α11 indeed regulated LOXL1 expression in stromal cells. Using cancer-associated fibroblast (CAF) with either a knockdown or overexpression of LOXL1, we demonstrated a role for LOXL1 in collagen matrix remodeling and collagen fiber alignment in vitro and in vivo in a NSCLC xenograft model. As a consequence of collagen reorganization in NSCLC tumor stroma, we showed that LOXL1 supported tumor growth and progression. Our findings demonstrate that stromal LOXL1, under regulation of integrin α11, is a determinant factor of NSCLC tumorigenesis and may be an interesting target in this disease

Tumor-Associated Regulatory T Cell Expression of LAIR2 Is Prognostic in Lung Adenocarcinoma

Cancer development requires a permissive microenvironment that is shaped by interactions between tumor cells, stroma, and the surrounding matrix. As collagen receptors, the leukocyte-associated immunoglobulin-like receptor (LAIR) family allows the immune system to interact with the extracellular matrix. However, little is known about their role in regulating tumor immunity and cancer progression. Methods: Genetic analysis of resected human lung adenocarcinoma was correlated to clinical-pathological characteristics, gene ontologies, and single cell RNA sequencing (scRNASeq). LAIR2 production was determined in subsets of immune cells isolated from blood leukocytes and lung adenocarcinoma tumor. Functional assays were used to determine the role of LAIR2 in tumorigenesis. Results: LAIR2 expression was adversely prognostic in lung adenocarcinoma. LAIR2 was preferentially produced by activated CD4+ T cells and enhanced in vitro tumor invasion into collagen. scRNASeq analysis of tumor infiltrating T cells revealed that LAIR2 expression co-localized with FOXP3 expressing cells and shared a transcriptional signature with tumor-associated regulatory T (Treg) cells. A CD4+ LAIR2+ Treg gene signature was prognostically significant in the TCGA dataset (n = 439; hazard ratio (HR) = 1.37; 95% confidence interval (CI), 1.05–1.77, p = 0.018) and validated in NCI Director’s Challenge lung adenocarcinoma dataset (n = 488; HR = 1.54; 95% CI, 1.14–2.09, p = 0.0045). Conclusions: Our data support a role for LAIR2 in lung adenocarcinoma tumorigenesis and identify a CD4+ LAIR2+ Treg gene signature in lung adenocarcinoma prognosis. LAIR2 provides a novel target for development of immunotherapies