Scavenger receptors typically bind to multiple ligands on a cell surface, including endogenous and modified host-derived molecules and microbial pathogens. They promote the elimination of degraded or harmful substances such as non-self or altered-self targets through endocytosis, phagocytosis, and adhesion. Currently, scavenger receptors are subdivided into eight classes based on several variations in their sequences due to alternative splicing. Since recent studies indicate targeting scavenger receptors has been involved in cancer prognosis and carcinogenesis, we will focus on the current knowledge about the emerging role of scavenger receptor classes A to E in cancer progression.

Over recent years, several new molecular and immunogenic therapeutic approaches to melanoma treatment have been approved and implemented in clinical practice. Mechanisms of resistance to these new therapies have become a major problem. Mutation-specific pharmacotherapy can result in simultaneous emergence of resistant clones at many separate body sites despite an initially positive therapeutic response. Additionally, treatments aimed at inducing apoptosis are subject to resistance due to escape through other known mechanisms of regulated cell death (RCD). In this review, we discuss the complexity in pharmacological manipulation of melanoma with c-Kit, BRAF, MEK, and/or mTOR mutant cell lines. This study also addresses melanoma evasion of cell death through modalities of RCD such as apoptosis, autophagy, and necroptosis. This study also examines new combination therapies which have been approved to target both cell cycle dysregulation and cell death pathways. Lastly, we recognize the importance of immunomodulation though manipulation of the body's natural killing mechanisms with CTLA4, PD1, and CSF1 inhibition. As we begin to recognize tumor cell activation of alternate pathways, evasion of programmed cell death, and manipulation of the tumor microenvironment, it is increasingly important to grasp the complexity of personalized therapy in melanoma treatment.
Apoptosis ; Autophagy ; Cell Cycle ; Cell Death* ; Cell Line ; Clone Cells ; Drug Therapy ; Hand Strength ; Homicide ; Humans ; Immunomodulation ; Melanoma* ; TOR Serine-Threonine Kinases ; Tumor Microenvironment ; United Nations

Melanoma is one of the most aggressive cancers in the world and is responsible for the majority of skin cancer deaths. Recent advances in the field of immunotherapy using active, adoptive, and antigen-specific therapeutic approaches, have generated the expectation that these technologies have the potential to improve the treatment of advanced malignancies, including melanoma. Treatment options for metastatic melanoma patients have been dramatically improved by the FDA approval of new therapeutic agents including vemurafenib, dabrafenib, and sorafenib. These kinase inhibitors have the potential to work in tandem with MEK, PI3K/AKT, and mTOR to inhibit the activity of melanoma inducing BRAF mutations. This review summarizes the effects of the new therapeutic agents against melanoma and the underlying biology of these BRAF inhibitors.
Biology ; Humans ; Immunotherapy ; Melanoma ; Mitogen-Activated Protein Kinase Kinases ; Phosphotransferases ; Skin Neoplasms

Psoriasis is a chronic, recurrent, heterogeneous, cutaneous inflammatory skin disease for which there is no cure. It affects approximately 7.5 million people in the United States. Currently, several biologic agents that target different molecules implicated in the pathogenic processes of psoriasis are being assessed in diverse clinical studies. However, relapse usually occurs within weeks or months, meaning there is currently no cure for psoriasis. Therefore, recent studies have discovered diverse new potential treatments for psoriasis: inhibitors of bacteria such as Staphylococcus aureus, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and neuropilin 1 (NRP1). A promising approach that has recently been described involves modifying antimicrobial peptides to develop new cutaneous anti-bacterial agents that target inflammatory skin disease induced by Staphylococcus. Increased expression of TRAIL and its death receptors DR4 and DR5 has been implicated in the pathogenesis of plaque psoriasis. In addition, TRAIL has the ability to inhibit angiogenesis by inducing endothelial cell death and by negative regulation of VEGF-induced angiogenesis via caspase-8-mediated enzymatic and non-enzymatic functions. Since NRP1 regulates angiogenesis induced by multiple signals, including VEGF, ECM and semaphorins, and also initiates proliferation of keratinocytes through NF-κB signaling pathway in involved psoriatic skin, targeting NRP1 pathways may offer numerous windows for intervention in psoriasis. In this review, we will focus on the current knowledge about the emerging role of synthetic antimicrobial peptides, TRAIL and NRP1 blocking peptides in the pathogenesis and treatment of psoriasis.
Anti-Bacterial Agents ; Bacteria ; Biological Factors ; Endothelial Cells ; Keratinocytes ; Necrosis ; Neuropilin-1 ; Peptides ; Psoriasis ; Receptors, Death Domain ; Recurrence ; Semaphorins ; Skin ; Skin Diseases ; Staphylococcus ; Staphylococcus aureus ; Therapeutic Uses ; TNF-Related Apoptosis-Inducing Ligand ; United States ; Vascular Endothelial Growth Factor A

BACKGROUND: We have recently shown that lipopolysaccharide (LPS), a major biologically active component of Gram-negative bacteria, mediate the activation of human keratinocytes by CD14 and Toll-like receptor (TLR 4). However, the mechanism of activation of keratinocytes by Gram-positive bacterial toxins remains unclear. OBJECTIVE: We investigated the mechanism of activation of human keratinocytes by lipoteichoic acid (LTA), a main stimulatory component of Gram-positive bacteria. METHODS: The effects of LTA on CD14, TLR2 and TLR4 mRNA expression were measured by quantitative RT-PCR in cultured human keratinocytes. To determine whether the effects of LTA on CD14, TLR2 and TLR4 expressions of the human keratinocytes were biologically functional, NF-kappaB nuclear translocation and IL-1alpha secretion were measured by immunofluorescence staining and ELISA, respectively. Furthermore, to determine whether these effects by LTA were specific for CD14, TLR2 and TLR4, some cells were pretreated with anti-CD14, anti-TLR2, or anti-TLR2 monoclonal antibodies prior to the addition of LTA. RESULTS: TLR4 mRNA expression on keratinocytes was augmented by exposure to LTA. LTA binding to keratinocytes resulted in NF-kappaB nuclear translocation and secretion of interleukin-1alpha. These responses by LTA were effectively abrogated by preincubating cells with anti-TLR4 monoclonal antibody, but not with anti-CD14 or anti- TLR2 monoclonal antibodies. CONCLUSION: These results indicate that, similar to LPS, LTA induces activation of human keratinocytes mainly through TLR4, however, in contrast to LPS signaling, LTA-induced keratinocyte activation is CD14-independent.
Antibodies, Monoclonal ; Bacterial Toxins ; Enzyme-Linked Immunosorbent Assay ; Fluorescent Antibody Technique ; Gram-Negative Bacteria ; Gram-Positive Bacteria ; Humans* ; Interleukin-1alpha ; Keratinocytes* ; NF-kappa B ; RNA, Messenger ; Toll-Like Receptor 4* ; Toll-Like Receptors*

Recent studies indicate that several Toll-like receptors (TLRs) are implicated in recognizing viral structures and instigating immune responses against viral infections. The aim of this study is to examine the expression of TLRs and proinflammatory cytokines in viral skin diseases such as verruca vulgaris (VV) and molluscum contagiosum (MC). Reverse transcription-polymerase chain reaction and immunostaining of skin samples were performed to determine the expression of specific antiviral and proinflammatory cytokines as well as 5 TLRs (TLR2, 3, 4, 7, and 9). In normal human skin, TLR2, 4, and 7 mRNA was constitutively expressed, whereas little TLR3 and 9 mRNA was detected. Compared to normal skin (NS), TLR3 and 9 mRNA was clearly expressed in VV and MC specimens. Likewise, immunohistochemistry indicated that keratinocytes in NS constitutively expressed TLR2, 4, and 7; however, TLR3 was rarely detected and TLR9 was only weakly expressed, whereas 5 TLRs were all strongly expressed on the epidermal keratinocytes of VV and MC lesions. In addition, the mRNA expression of IFN-beta and TNF-alpha was upregulated in the VV and MC samples. Immunohistochemistry indicated that IFN-beta and TNF-alpha were predominately localized in the granular layer in the VV lesions and adjacent to the MC bodies. Our results indicated that VV and MC skin lesions expressed TLR3 and 9 in addition to IFN-beta and TNF-alpha. These viral-induced proinflammatory cytokines may play a pivotal role in cutaneous innate immune responses.
Cytokines/metabolism ; *Gene Expression Regulation ; Humans ; Immunohistochemistry/methods ; Inflammation ; Interferon-beta/biosynthesis ; Keratinocytes/cytology ; Models, Biological ; Molluscum Contagiosum/*metabolism ; Toll-Like Receptor 3/biosynthesis ; Toll-Like Receptor 9/biosynthesis ; Toll-Like Receptors/*biosynthesis ; Tumor Necrosis Factor-alpha/biosynthesis ; Warts/*metabolism

Electroactive and/or electrically conductive polymers have shown potential applications in the culture of excitable cells and as the electroactive scaffolds for neuronal or cardiac tissue engineering. The biocompatibility of the conductive polymer can be improved by covalently grafting or blending with oligo- or polypeptides. The new progresses in this area on two types of conductive polymers, polypyrrole and polyaniline (PANi) are reviewed in this paper. The studies of oligopeptide-modified PANi and electrospun PANi/gelatin nanofibers are highlighted.
Aniline Compounds ; chemistry ; Animals ; Biocompatible Materials ; chemistry ; Cells, Cultured ; Materials Testing ; Mice ; Polymers ; chemistry ; Pyrroles ; chemistry ; Rats ; Tissue Engineering