In situ activation of mouse macrophages and therapy of spontaneous renal cell cancer metastasis by liposomes containing the lipopeptide CGP 31362

Optimization of Nanoparticles for Smart Drug Delivery: A Review

Nanoparticle delivery systems have good application prospects in the treatment of various diseases, especially in cancer treatment. The effect of drug delivery is regulated by the properties of nanoparticles. There have been many studies focusing on optimizing the structure of nanoparticles in recent years, and a series of achievements have been made. This review summarizes the optimization strategies of nanoparticles from three aspects-improving biocompatibility, increasing the targeting efficiency of nanoparticles, and improving the drug loading rate of nanoparticles-aiming to provide some theoretical reference for the subsequent drug delivery of nanoparticles.

Macrophages as a "weapon" in anticancer cellular immunotherapy

Anticancer immunotherapy is a treatment that activates the immune system to fight the tumor. Immunotherapy has several advantages over other cancer treatments in that anticancer immunotherapy displays high specificity, low side effects, and can combine with various conventional therapies. In recent years, oncologists have shown increasing interest in using macrophages for adoptive cell therapy and predict a bright future of macrophage-directed therapy for eliminating cancer. The focus of increased research interest is the classically activated M1 macrophages exhibiting pronounced tumoricidal activity, and the alternatively activated M2 tumor-associated macrophages, which otherwise help malignant cells evading attack by the immune system. M1 macrophages may represent an effective weapon in anticancer cellular immunotherapy, and the use of autoimmune macrophages properly prepared for antitumor administration is one of the promising ways for personalized therapy of cancer patients. The present report mainly discusses some modern aspects of the problem in application of activated M1 macrophage in anticancer therapy and reviews relevant publications up to 2021.

Lung Macrophages: Multifunctional Regulator Cells for Metastatic Cells

Metastasis is responsible for most of the cancer-associated deaths and proceeds through multiple steps. Several lines of evidence have established an indispensable involvement of macrophages present at the primary tumor sites in various steps of metastasis, from primary tumor growth to its intravasation into circulation. The lungs encompass a large, dense vascular area and, therefore, are vulnerable to metastasis, particularly, hematogenous ones arising from various types of neoplasms. Lung tissues constitutively contain several types of tissue-resident macrophages and circulating monocytes to counteract potentially harmful exogenous materials, which directly reach through the airway. Recent advances have provided an insight into the ontogenetic, phenotypic, and functional heterogeneity of these lung macrophage and monocyte populations, under resting and inflammatory conditions. In this review, we discuss the ontogeny, trafficking dynamics, and functions of these pulmonary macrophages and monocytes and their potential roles in lung metastasis and measures to combat lung metastasis by targeting these populations.

Intratumoural injection of the toll-like receptor-2/6 agonist 'macrophage-activating lipopeptide-2' in patients with pancreatic carcinoma: a phase I/II trial

This phase I/II trial examined safety and efficacy of the toll-like receptor 2/6 agonist MALP-2 in combination with gemcitabine in patients with incompletely resectable pancreas carcinomas. MALP-2 is a toll-like receptor 2/6 agonist, acts as an immunological adjuvant, and has been described recently to prolong survival in a mouse model of an orthotopic, syngeneic pancreas tumour. Male and female patients with incompletely resectable pancreas carcinomas were eligible while those with R0 or R1 resections or with peritoneal carcinosis were excluded. Ten patients were injected intratumourally during surgery with 20-30 microg MALP-2 followed by postoperative chemotherapy. Samples were taken from peripheral blood and wound secretion, and assayed for cell content, cytokine and CRP levels, and NK activity. An MALP-2 dose of 20 microg was well tolerated. Clear signs of local MALP-2 effects were presented by the influx of lymphocytes and monocytes in wound secretions, and abolishment of inhibition of NK activity. The actual mean survival is 17.1+/-4.2 months; the median survival being 9.3 months. Two patients are still alive after 31 months. Up to 20 microg MALP-2 was well tolerated, and no systemic side effects were noted. The mean survival of 17.1 months is remarkably high.

Differential regulation of type IV collagenases and metalloelastase in murine macrophages by the synthetic bacterial lipopeptide JBT 3002

We determined whether the expression of matrix metalloproteinases (MMP) and tissue inhibitors of MMPs (TIMP) in murine macrophages is regulated by the novel synthetic bacterial lipopeptide JBT 3002. Multilamellar liposomes (MLV) encapsulating JBT 3002 (MLV-JBT 3002) stimulated the production of 72-kDa and 92-kDa (gelatinase A and B) type IV collagenase and inhibited the production of murine metalloelastase (MME) in a dose-dependent manner in murine peritoneal macrophages. MLV-JBT 3002 also induced production of TIMP-1. MLV-JBT 3002 did not induce collagenase production in tumor cells. Priming murine macrophages with interferon-gamma (IFN-gamma) inhibited JBT 3002-stimulated production of both MMP-9 and MMP-2 and further inhibited production of MME by a mechanism involving nitric oxide (NO). This conclusion is based on data showing that IFN-gamma failed to inhibit production of MMP in the presence of L-methyl arginine or in macrophages from inducible nitric oxide synthase knockout mice. These data suggest that JBT 3002 differentially regulates the production of various MMPs and TIMP in macrophages.

Mycoplasmal lipopeptide MALP-2 induces the chemoattractant proteins macrophage inflammatory protein 1alpha (MIP-1alpha), monocyte chemoattractant protein 1, and MIP-2 and promotes leukocyte infiltration in mice

Natural as well as experimental infections with pathogenic mycoplasmas lead to cellular responses characterized by early polymorphonuclear leukocyte influx, which in turn is followed by infiltration of macrophages. Since some of the most potent leukocyte chemoattractants are macrophage products, we investigated whether the 2-kDa macrophage-activating lipopeptide (MALP-2) from Mycoplasma fermentans was capable of inducing chemoattractant chemokines and initiating an in vivo inflammatory effect. MALP-2 was a potent in vitro inducer of the chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), monocyte chemoattractant protein 1 (MCP-1), and MIP-2, yielding a maximal response at 0.1 ng/ml (5 x 10(-11) M). Leukocyte infiltration was determined after intraperitoneal injection of MALP-2, liposome-encapsulated MALP-2, and heat-killed mycoplasmas. There was a steady increase in the number of peritoneal cells over 72 h in response to these agents. Polymorph counts were maximal by 24 to 48 h, decreasing thereafter. Monocytes/macrophages had significantly increased after 3 days. MIP-1alpha, MCP-1, and MIP-2 levels in serum or peritoneal lavage fluid were determined. MIP-1alpha and MCP-1 levels were elevated by 2 to 6 h after injection and were still above control values after 24 h. In contrast, MIP-2 levels reached their maximum at 2 h, dropping to control values after 24 h. We conclude that macrophage-stimulating mycoplasmal lipoproteins, exemplified by MALP-2, play an important role in the late phase of phagocyte recruitment at sites of infection and that this is affected by leukoattractive chemokines.

A nucleoside-sensitive organic cation transporter in opossum kidney cells

Renal secretion of organic cations and anions are pleiotropic, active processes in mammals. Some nucleosides such as deoxyadenosine (dAdo), 2-chlorodeoxyadenosine, and azidothymidine are secreted by human and rodent kidneys. Previous work (J. A. Nelson, J. F. Kuttesch, Jr., and B. H. Herbert. Biochemical Pharmacology 32: 2323-2327, 1983) indicated a role for the classic organic cation transporter (OCT) in the secretion of the dAdo analog, 2'-deoxytubercidin, by mouse kidney. Using [14C]tetraethylammonium bromide ([14C]TEA) as a substrate, we tested several renal cell lines for a nucleoside-sensitive OCT. American opossum kidney proximal tubule cells (OK) express a cimetidine-sensitive and metabolic-dependent ability to efflux TEA. Other classic OCT inhibitors and several nucleosides also inhibit TEA efflux by these cells in a manner reflecting structural specificity for the carrier. Inhibition of OCT by nucleosides is not a universal feature of OCTs, since TEA transport mediated by cloned rat kidney OCT2 in the Xenopus laevis oocyte system was not inhibited by the same nucleosides. In conclusion, OK cells appear to possess an OCT that may also transport some nucleosides by a novel carrier.

Protection of mice against SV40 tumours by Pam3Cys, MTP-PE and Pam3Cys conjugated with the SV40 T antigen-derived peptide, K(698)-T(708)

The intraperitoneal injection of Balb/c mice with synthetic analogues of adjuvants S-[2,3-bis(palmitoyloxy)-(2-RS)-propyl]-N-palmitoyl-R-cysteine (Pam3Cys) or muramyltripeptide phosphatidylethanolamine (MTP-PE) inhibited the tumourigenic growth of subcutaneously injected VLM cells, a syngeneic simian virus 40 (SV40)-transformed cell line. Furthermore, the Pam3Cys conjugate of K698-T708 (KT), which represents the C-terminal undecapeptide of the SV40 large tumour (T) antigen, was tumour-protective. Also syngeneic spleen cells, preincubated in vitro with this Pam3Cys-KT derivative, which anchores spontaneously at the cell membrane, were, through SV40 tumour mimicry, tumour-protective. The protection was impaired by treatment of the mice with either anti-CD4, anti-CD8 IgG, anti asialo GM1 antiserum or dextrane sulfate, which deplete the CD4+, CD8+ and NK cells or the macrophages, respectively. In summary, SV40 tumour transplantation resistance can be experimentally elicited by a tumour-epitope-specific vaccine. In the absence of an immunogenic epitope protection was obtained by administration of biological response modifiers. Protection is effected by SV40-T-antigen-specific cytotoxic lymphocytes in cooperation with NK cells and macrophages.

Expression of inflammatory cytokines by murine macrophages activated with a new synthetic lipopeptide JT3002

The present study was undertaken to investigate the effect of JT3002, a new synthetic analogue of a lipoprotein from the outer wall of a gram-negative bacterium on the production of cytokines by mouse peritoneal macrophages. Multilamellar liposomes containing different concentrations of JT3002 induced production of the inflammatory cytokines tumor necrosis factor-alpha, interleukin-1 alpha, and interleukin-6 by macrophages in dose- and time-dependent manners. The presence of interferon-gamma enhanced production of tumor necrosis factor-alpha by macrophages exposed to lower concentrations of JT3002 and induced the release of nitric oxide, a potent cytolytic molecule of activated macrophages. Unlike lipopolysaccharide, JT3002 activated macrophages independently of serum, but like lipopolysaccharide, it required protein tyrosine kinase.