Muramyl peptides augment cytotoxic effect of tumor necrosis factor-alpha in combination with cytotoxic drugs on tumor cells

Efficacy and safety of glucosaminylmuramyl dipeptide in treatment of human papillomavirus-associated diseases: a systematic review

Introduction. Human papillomavirus infection (HPV-infection) remains one of the most important health problems as it significantly reduces the quality of life and stigmatizes the patients. Also, the prevalence of cervical cancer – the most severe outcome of the HPV-infection is 5 % of the global burden of cancer. Although vaccination against human papillomavirus has been proved efficient, its availability in Russia continues to be limited. Therefore, it is important to review other methods of HPV-infection control. A number of studies have confirmed the efficacy of glucosaminylmuramyl dipeptide (GMDP) in the treatment of diseases associated with HPV-infection, but no systematic evaluation of these studies has been published in the available literature.

Aim: to analyze the data on the efficacy and safety of GMDP in the treatment of diseases and conditions associated with HPVinfection.

Materials and methods. We used the PRISMA approach. The search for the relevant publications was conducted in international scientific databases: the Scientific Electronic Library, the Google Scholar, the ScienceDirect, the Cochrane Community Library, the Pubmed/MEDLINE, and clinical research registries. For this systematic analysis, only full-text publications were used. We evaluated the reliability of evidence and the methodological quality of the studies.

Results. We used the following search queries: "glucosaminyl-muramyl dipeptide", "glucosamine L'muramyl dipeptide", "H-acetylglucosaminyl-H-acetylmuramyl dipeptide", "GMDP", "Licopid" (both in Russian and English transcriptions). Based on the results of the screening, 14 full-text publications were selected. At the final stage, review articles with secondary data were excluded; also excluded were original articles published in doubtful resources and those with an unclear status of peer reviewing. This systematic analysis includes 7 publications of acceptable methodological quality. Here, we summarize the consistent conclusions derived from these reports: the addition of therapy with GMDP to local (surgical) methods increases the efficacy of treatment and the duration of remission; destruction of condylomas is more effective when combined with the course of GMDP as compared to using the local destruction alone; GMDP enhances the production of cytokines that have a direct antiviral and antiproliferative effect in HPV-infection (interleukin-1, tumor necrosis factor alpha, gamma-interferon); GMDP causes normalization of cellular and humoral immunity (T-lymphocytes, T-cytotoxic lymphocytes, B-lymphocytes, CD3+, CD4+, CD8+, CD16+, and CD72+ lymphocytes, as well as the production of serum immunoglobulins IgA, IgG, and IgM). A high safety profile of GMDP is evidenced from the absence of reports on adverse events.

Discussion. The recommendation for the inclusion of GMDP into a comprehensive treatment for HPV-infection in addition to local interventions is a strong recommendation. The differences between the Russian and international approaches can be explained by the difference in the available resources and funding. We propose to test whether using GMDP for reducing the risk of recurrent HPV-infection is beneficial in terms of pharmacoeconomics. Conclusion. The high efficacy and safety of GMDP in the combined therapy of HPV-infection has been confirmed. Further carefully designed studies on GMDP are needed.

Harnessing the untapped potential of nucleotide-binding oligomerization domain ligands for cancer immunotherapy

In the last decade, cancer immunotherapy has emerged as an effective alternative to traditional therapies such as chemotherapy and radiation. In contrast to the latter, cancer immunotherapy has the potential to distinguish between cancer and healthy cells, and thus to avoid severe and intolerable side‐effects, since the cancer cells are effectively eliminated by stimulated immune cells. The cytosolic nucleotide‐binding oligomerization domains 1 and 2 receptors (NOD1 and NOD2) are important components of the innate immune system and constitute interesting targets in terms of strengthening the immune response against cancer cells. Many NOD ligands have been synthesized, in particular NOD2 agonists that exhibit favorable immunostimulatory and anticancer activity. Among them, mifamurtide has already been approved in Europe by the European Medicine Agency for treating patients with osteosarcoma in combination with chemotherapy after complete surgical removal of the primary tumor. This review is focused on NOD receptors as promising targets in cancer immunotherapy as well as summarizing current knowledge of the various NOD ligands exhibiting antitumor and even antimetastatic activity in vitro and in vivo.

Natural glycoconjugates with antitumor activity

Cancer is one of the major causes of death worldwide. As a consequence, many different therapeutic approaches, including the use of glycosides as anticancer agents, have been developed. Various glycosylated natural products exhibit high activity against a variety of microbes and human tumors. In this review we classify glycosides according to the nature of their aglycone (non-saccharidic) part. Among them, we describe anthracyclines, aureolic acids, enediyne antibiotics, macrolide and glycopeptides presenting different strengths and mechanisms of action against human cancers. In some cases, the glycosidic residue is crucial for their activity, such as in anthracycline, aureolic acid and enediyne antibiotics; in other cases, Nature has exploited glycosylation to improve solubility or pharmacokinetic properties, as in the glycopeptides. In this review we focus our attention on natural glycoconjugates with anticancer properties. The structure of several of the carbohydrate moieties found in these conjugates and their role are described. The structure–activity relationship of some of these compounds, together with the structural features of their interaction with the biological targets, are also reported. Taken together, all this information is useful for the design of new potential anti-tumor drugs.

GMDP augments antitumor action of the CP/TNFalpha combination in vivo

We have shown that glucosaminyl muramyl dipeptide (GMDP) has been augmented the antitumor action of chemotherapy drug cisplatin and tumor necrosis factor-alpha (TNFalpha) on the Ehrlich ascites carcinoma and melanoma B-16 mouse tumor models. The doses of cisplatin, TNFalpha and GMDP and also the conditions of the drugs combination injection provided 100% survival of mice with Ehrlich ascites carcinoma were found. Furthermore, it was shown first that GMDP has been decreased toxicity of the cisplatin/TNFalpha combination and normalized the changes in the experimental mice hematological parameters which were produced by the CP/TNFalpha combination.

Targeting tumors with peptides from natural sources

Peptide-based therapies offer the potential for non-genotoxic, genotype-specific alternatives, or adjuvants, to the current range of traditional cancer treatments. Such a patient-tailored cancer-cell-directed therapeutic approach should have fewer side effects and could well be more effective than the current drug- or combination-based regimens. Here, we review the potential of novel natural anticancer peptides such as necrotic peptides, apoptotic peptides, function-blocking peptides, antiangiogenic peptides and immunostimulatory peptides in the context of their ability to induce tumor regression. We focus on the therapeutic prospects of anticancer peptides and their possible application in tumor therapy.

NLR proteins: integral members of innate immunity and mediators of inflammatory diseases

The innate immune system is the first line of defense against microorganisms and is conserved in plants and animals. The nucleotide-binding domain, leucine rich containing (NLR) protein family is a recent addition to the members of innate immunity effector molecules. These proteins are characterized by a central oligomerization domain, termed nucleotide-binding domain (NBD) and a protein interaction domain, leucine-rich repeats (LRRs) at the C terminus. It has been shown that NLR proteins are localized to the cytoplasm and recognize microbial products. To date, it is known that Nod1 and Nod2 detect bacterial cell wall components, whereas Ipaf and Naip detect bacterial flagellin, and NACHT/LRR/Pyrin 1 has been shown to detect anthrax lethal toxin. NLR proteins comprise a diverse protein family (over 20 in humans), indicating that NLRs have evolved to acquire specificity to various pathogenic microorganisms, thereby controlling host-pathogen interactions. Activation of NLR proteins results in inflammatory responses mediated by NF-kappaB, MAPK, or Caspase-1 activation, accompanied by subsequent secretion of proinflammatory cytokines. Mutations in several members of the NLR protein family have been linked to inflammatory diseases, suggesting these molecules play important roles in maintaining host-pathogen interactions and inflammatory responses. Therefore, understanding NLR signaling is important for the therapeutic intervention of various infectious and inflammatory diseases.