Enniatin A Analogues as Novel Hsp90 Inhibitors that Modulate Triple-Negative Breast Cancer.

The 90 kilo-Dalton heat shock protein (Hsp90) is a molecular chaperone that facilitates the maturation of nascent polypeptides into their biologically active conformation. Because many of the >400 known client protein substrates are implicated in the development/progression of cancer, it is hypothesized that Hsp90 inhibition will simultaneously shut down numerous oncogenic pathways. Unfortunately, most of the small molecule Hsp90 inhibitors that have undergone clinical evaluation thus far have failed due to various toxicities. Therefore, the disruption of Hsp90 protein-protein interactions with cochaperones and/or client substrates has been proposed as an alternative way to achieve Hsp90 inhibition without such adverse events. The hexadepsipeptide Enniatin A (EnnA) has recently been reported to be one such inhibitor that also manifests immunogenic activity. Herein, we report preliminary structure-activity relationship (SAR) studies to determine the structural features that confer this unprecedented activity for an Hsp90 inhibitor. Our studies find that EnnA's branching moieties are necessary for its activity, but some structural modifications are tolerated.

Enniatin A inhibits the chaperone Hsp90 and unleashes the immune system against triple-negative breast cancer.

Low response rates and immune-related adverse events limit the remarkable impact of cancer immunotherapy. To improve clinical outcomes, preclinical studies have shown that combining immunotherapies with N-terminal Hsp90 inhibitors resulted in improved efficacy, even though induction of an extensive heat shock response (HSR) and less than optimal dosing of these inhibitors limited their clinical efficacy as monotherapies. We discovered that the natural product Enniatin A (EnnA) targets Hsp90 and destabilizes its client oncoproteins without inducing an HSR. EnnA triggers immunogenic cell death in triple-negative breast cancer (TNBC) syngeneic mouse models and exhibits superior antitumor activity compared to Hsp90 N-terminal inhibitors. EnnA reprograms the tumor microenvironment (TME) to promote CD8+ T cell-dependent antitumor immunity by reducing PD-L1 levels and activating the chemokine receptor CX3CR1 pathway. These findings provide strong evidence for transforming the immunosuppressive TME into a more tumor-hostile milieu by engaging Hsp90 with therapeutic agents involving novel mechanisms of action.

Tribbles homolog 3-mediated targeting the AKT/mTOR axis in mice with retinal degeneration.

Various retinal degenerative disorders manifest in alterations of the AKT/mTOR axis. Despite this, consensus on the therapeutic targeting of mTOR in degenerating retinas has not yet been achieved. Therefore, we investigated the role of AKT/mTOR signaling in rd16 retinas, in which we restored the AKT/mTOR axis by genetic ablation of pseudokinase TRB3, known to inhibit phosphorylation of AKT and mTOR. First, we found that TRB3 ablation resulted in preservation of photoreceptor function in degenerating retinas. Then, we learned that the mTOR downstream cellular pathways involved in the homeostasis of photoreceptors were also reprogrammed in rd16 TRB3-/- retinas. Thus, the level of inactivated translational repressor p-4E-BP1 was significantly increased in these mice along with the restoration of translational rate. Moreover, in rd16 mice manifesting decline in p-mTOR at P15, we found elevated expression of Beclin-1 and ATG5 autophagy genes. Thus, these mice showed impaired autophagy flux measured as an increase in LC3 conversion and p62 accumulation. In addition, the RFP-EGFP-LC3 transgene expression in rd16 retinas resulted in statistically fewer numbers of red puncta in photoreceptors, suggesting impaired late autophagic vacuoles. In contrast, TRIB3 ablation in these mice resulted in improved autophagy flux. The restoration of translation rate and the boost in autophagosome formation occurred concomitantly with an increase in total Ub and rhodopsin protein levels and the elevation of E3 ligase Parkin1. We propose that TRB3 may retard retinal degeneration and be a promising therapeutic target to treat various retinal degenerative disorders.

Biotin Deficiency Induces Th1- and Th17-Mediated Proinflammatory Responses in Human CD4+ T Lymphocytes via Activation of the mTOR Signaling Pathway.

Biotin (vitamin B7) is essential for human health because of its involvement, as a cofactor, in a variety of critical cellular metabolic reactions. Previous studies have shown that biotin deficiency enhances inflammation, and certain chronic inflammatory diseases are associated with biotin deficiency; however, the mechanisms that mediate the association between biotin status and inflammation are not well understood. In this study, we examined the effect of biotin deficiency on human CD4+ T cell responses to determine their role in biotin deficiency-associated inflammation. Our investigations revealed that anti-CD3/CD28-stimulated CD4+ T cells cultured in biotin-deficient medium secreted significantly enhanced levels of the proinflammatory cytokines IFN-γ, TNF, and IL-17. Expression of the transcription factors T-bet and RORγt was increased, whereas Foxp3 expression was decreased, in biotin-deficient CD4+ T cells. The percentage of T regulatory cells was also decreased under biotin-deficient condition. A similar increase in T-bet, RORγt, and proinflammatory cytokine levels, as well as a decrease in Foxp3, was observed in inguinal lymph nodes of mice fed a biotin-deficient diet relative to pair-fed controls. Furthermore, differentiation of CD4+ T cells toward Th1 and Th17 cells was also enhanced. In vitro and in vivo investigations indicated that the increased inflammatory response was due to enhanced activation of the mammalian target of rapamycin signaling pathway in biotin-deficient CD4+ T cells. In summary, these results demonstrate that biotin deficiency enhances the inflammatory responses in CD4+ T cells, which may contribute to inflammation associated with biotin deficiency.

Characterization of Calcined Jade and its immunomodulatory effect on macrophage isolated from Swiss albino mice.

Calcined Jade (CJ) is a metasilicate frequently used in traditional system of medicine as tonic to vital organs with several other pharmacological activities. X-ray powder diffraction (XRPD), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectroscopy (AAS) and CHNS analyzer techniques were used to characterize CJ sample. CJ was administered orally to Swiss albino mice at a dose of 50, 75, 100 and 200 µg/kg body weight for 10 days and modulation of the macrophage mediated innate immune responses was studied. Flow cytometric analysis of TLR-2/4 on peritoneal macrophage revealed elevated expression of TLR-2 as compared to control. Significant increase in phagocytic activity was observed in peritoneal macrophage. The lymphoid organs weight and other toxicity parameters did not exhibit any harmful effect. To evaluate the presence of nanoparticles, CJ was dissolved in milli Q water, filtered and lyophilized. Transmission electron microscopic (TEM) analysis revealed the presence of spherical nanoparticles in CJ [14.7-142.0 nm dimension with average particle size of 64.6 nm]. In conclusion, we report stimulation of innate immune responses by CJ may partly be due to the formation of nanoparticles. Further experiments using isolated nanoparticles may further validate the role of nanoparticles.

Zika virus outbreak: an overview of the experimental therapeutics and treatment.

Zika virus (ZIKV) infection is a new emerging threat around the globe which might be responsible for microcephaly and Guillain-Barre syndrome in the infants. Recently, ZIKV outbreak has caused a public health crisis in Brazil after being linked to a sharp increase in birth defects. ZIKV is ssRNA virus belongs to the family Flaviviridae. It is mainly transmitted by mosquito bite specifically Aedes species and disease symptoms include fever, joint pain, muscle pain, rash, conjunctivitis, and headache. The reservoir of ZIKV is still not known. Protection at personal level by avoiding mosquito bite would help to reduce the incidence of the disease. Control of ZIKV infection by vaccination or antiviral drug either from modern, complementary and alternative medicines may be considered to be one of the most effective strategies in the long run. Large scale immunization of susceptible human population is highly required to prevent this deadly disease. Attempts should be made as soon as possible to develop effective vaccines or antiviral to prevent ZIKV infection. This article provides a current overview of the experimental therapeutics and treatment options based on modern, complementary and alternative medicines.

Amelioration of obesity-associated inflammation and insulin resistance in c57bl/6 mice via macrophage polarization by fish oil supplementation.

Enormous phenotypic plasticity makes macrophages the target cells in obesity-associated inflammatory diseases. Thus, nutritional components that polarize macrophages toward antiinflammatory phenotype can partially reverse inflammatory diseases like insulin resistance. In the present study, macrophage-polarizing and insulin-sensitizing properties of fish oil (FO) were evaluated in obese insulin-resistant c57bl/6 mice fed high-fat diet (HFD-IR) after oral supplementation with FO (4, 8 or 16mg/kg body weight) and compared to lean and HFD-IR mice. FO-supplemented HFD-IR mice exhibited reduced adiposity index, serum cholesterol and triglycerides and increased insulin sensitization and showed improved adipose tissue physiology under light and transmission electron microscopy. NF-κB/P65 expression showed a downward shift on FO supplementation. The surface marker of M1 macrophages (CD-86) and the TLR-4 expression reduced with the increased supplementation of FO. Expression of arginase 1, an important marker of M2 macrophages, increased in a dose-dependent manner in response to FO dosage, which was observed at protein level by the western blotting and at mRNA level by real-time PCR. The cytokine profile of adipose tissue macrophages showed a steep shift toward antiinflammatory ones (IL-4 and IL-10) from the inflammatory TNF-α, IFN-γ, IL-2 and IL-1ß. Thus, macrophage polarization seems to be the plausible mechanism via which FO alleviates obesity-induced inflammation and insulin resistance.

Implication of protein tyrosine phosphatase SHP-1 in cancer-related signaling pathways.

The altered expression of SHP-1 (SH2 domain-containing protein tyrosine phosphatase) as a consequence of promoter hypermethylation or mutations has evidently been linked to cancer development. The notion of being a cancer drug target is conceivable as SHP-1 negatively regulates cell cycle and inflammatory pathways which are an inevitable part of oncogenic transformation. In the present review, we try to critically analyze the role of SHP-1 in cancer progression via regulating the above mentioned pathways with the major emphasis on cell cycle components and JAK/STAT pathway, commencing with the SHP-1 biology in immune cell signaling. Lastly, we have provided the future directions for researchers to encourage SHP-1 as a prognostic marker and curative target for this debilitating disease called as cancer.

Balanced TH1 and TH2 immunopotentiating effects of silicates partly containing nanoparticles present in calcined serpentine.

Calcined Serpentine (CS) is used in various formulations of alternative systems of medicine as a tonic to vital organs and as an anti-inflammatory agent. The process of calcination or incineration is believed to render non-toxic, gently absorbable, adaptable and digestible properties to the mineral compounds. The present study characterized CS and also evaluated its immunostimulatory potential. CS was characterized by using transmission electron microscopy (TEM), X-ray powder diffraction, atomic absorption spectroscopy and CHNS analysis. The characterized CS was further evaluated for its immunomodulatory potential in Swiss mice. X-Ray diffraction analysis revealed that the CS contained silicates of magnesium, calcium and iron as major minerals. Elemental composition and heavy metal analyses showed a presence of various inorganic elements/heavy metals, albeit at levels well below daily permissive intake values. TEM analysis of the test CS revealed a presence of nano particles with an average size of 10-20 nm (≈ 26% of total material). Oral administration of CS to mice at 50, 75, 100 or 200 µg/kg body weight for 10 days led to enhanced levels of total IgG, IgG1, IgG2a and IgG2b in ovalbumin-immunized mice as well as ex vivo lymphocyte proliferation and levels of TH1 (IL-2, IFNγ) and TH2 (IL-4, IL-10) cytokines produced by their cultured splenocytes. Similarly, CS treatment resulted in enhanced delayed-type hypersensitivity responses in GRBC-primed hosts. CS also activated host peritoneal macrophages, as indicated by increases in phagocytic activity and in TLR-2, CD80 and CD86 expression. The CS did not affect liver, kidney and spleen histology. Taken together, the results indicated that absorbed CS was stimulatory of host cell-mediated immune responses. It is hypothesized for now that the immunomodulatory effect of CS may have been due, in part, to a presence of nanoparticles on the CS; further study is required to validate this viewpoint.

Macrophage polarization: the link between inflammation and related diseases.

OBJECTIVE: In the present review, we try to critically evaluate the two faces of the macrophages and their roles in relation to gene alteration in some inflammatory conditions. The pros- and cons of each type of macrophage in immunologic outcomes are discussed. INTRODUCTION: If ''Diversity is the rule of nature'', macrophages have proven to be its obedient followers. A cell type that was classically considered to be activated by Interferon-c, under the influence of T(H)-1 type of response and a well-accepted warrior of cellular immunity to the intracellular pathogens is not as simple as once considered. Past decade has revolutionized this notion with the advent of T(H)-2 influenced alternatively activated macrophages, now established as wound repairing and tissue regenerating. METHODS: Literature survey was done to present a detailed study on this macrophage dichotomy and its relevance to immune disorders via expression of some critical genes, nuclear factor kappa-light-chain-enhancer of activated B cells, peroxisome proliferator-activated receptors and SH2-containing inositol-50-phosphatase 1, highly implicated in a myriad of immunological emergencies like inflammation, insulin resistance, wound healing, cancer, etc. CONCLUSION: The evaluation of macrophage dichotomy in these disorders may prove to be the first step towards the formulation of innovative therapeutic approaches.

Antigen specific immune enhancement of innate and acquired immunity by pearl in ashed form.

The present study evaluated mineral compound, pearl in ashed form [PAF], for its potential as oral immunomodulator. ICP-MS, atomic absorption spectroscopy, CHNS analysis and XRD analysis were used for characterization of PAF. Surface antigen markers (TLR-2/4 and CD-80/86) were studied by flow cytometry. At dose concentration of 25, 50, 100 and 500 µg/kg body wt., administrated orally for 10 days, TLR-2 expression on murine peritoneal macrophage increased while TLR-4 expression was reduced as compared to control. There was an increase in OVA and mitogen (Con-A) specific lymphocyte proliferation in OVA immunized mice. Also, level of both Th1 (IL-2/IFN-γ) and Th2 (IL-4/IL-10) cytokines, and level and titer of total IgG, IgG1, IgG2a and IgG2b of OVA immunized mice significantly increased. The level of Inflammatory cytokines (IL-1ß and TNF-α) did not increase significantly. Enhancement in T and B cell immune responses may be possibly due to significantly enhanced expression of CD-80 and CD-86 co-stimulatory signals as observed using flow cytometry. Also, enhanced phagocytic activity and DTH response exhibit stimulatory effect of PAF on innate and cell mediated immune response. Histopathological analysis of liver, kidney and spleen and analysis of other toxicity parameters, such as effect on body weight, lymphoid organ weight and cellularity, revealed PAF to exhibit no toxic effects. PAF seems to be a promising balanced Th1 and Th2 directing immunomodulator, possibly activating TLR2 through TIR domain-containing adaptor inducing interferon ß (TRIF)-dependent pathway that leads to T-cell activation and promotes effective immune responses and may find useful application clinically.