Neem leaf glycoprotein induces perforin-mediated tumor cell killing by T and NK cells through differential regulation of IFNgamma signaling

Neem Leaf Glycoprotein Disrupts Exhausted CD8+ T-Cell-Mediated Cancer Stem Cell Aggression

Targeting exhausted CD8+ T-cell (TEX)-induced aggravated cancer stem cells (CSC) holds immense therapeutic potential. In this regard, immunomodulation via Neem Leaf Glycoprotein (NLGP), a plant-derived glycoprotein immunomodulator is explored. Since former reports have proven immune dependent-tumor restriction of NLGP across multiple tumor models, we hypothesized that NLGP might reprogram and rectify TEX to target CSCs successfully. In this study, we report that NLGP's therapeutic administration significantly reduced TEX-associated CSC virulence in in vivo B16-F10 melanoma tumor model. A similar trend was observed in in vitro generated TEX and B16-F10/MCF7 coculture setups. NLGP rewired CSCs by downregulating clonogenicity, multidrug resistance phenotypes and PDL1, OCT4, and SOX2 expression. Cell cycle analysis revealed that NLGP educated-TEX efficiently pushed CSCs out of quiescent phase (G0G1) into synthesis phase (S), supported by hyper-phosphorylation of G0G1-S transitory cyclins and Rb proteins. This rendered quiescent CSCs susceptible to S-phase-targeting chemotherapeutic drugs like 5-fluorouracil (5FU). Consequently, combinatorial treatment of NLGP and 5FU brought optimal CSC-targeting efficiency with an increase in apoptotic bodies and proapoptotic BID expression. Notably a strong nephron-protective effect of NLGP was also observed, which prevented 5FU-associated toxicity. Furthermore, Dectin-1-mediated NLGP uptake and subsequent alteration of Notch1 and mTOR axis were deciphered as the involved signaling network. This observation unveiled Dectin-1 as a potent immunotherapeutic drug target to counter T-cell exhaustion. Cumulatively, NLGP immunotherapy alleviated exhausted CD8+ T-cell-induced CSC aggravation. Implications: Our study recommends that NLGP immunotherapy can be utilized to counter ramifications of T-cell exhaustion and to target therapy elusive aggressive CSCs without evoking toxicity.

Neem Leaf Extract Exhibits Anti-Aging and Antioxidant Effects from Yeast to Human Cells

Neem leaves have long been used in traditional medicine for promoting longevity. However, the precise mechanisms underlying their anti-aging effects remain elusive. In this study, we investigated the impact of neem leaf extract (NLE) extracted from a 50% ethanol solution on the chronological lifespan of Saccharomyces cerevisiae, revealing an extension in lifespan, heightened oxidative stress resistance, and a reduction in reactive oxygen species. To discern the active compounds in NLE, LC/MS and the GNPS platform were employed. The majority of identified active compounds were found to be flavonoids. Subsequently, compound-target pharmacological networks were constructed using the STP and STITCH platforms for both S. cerevisiae and Homo sapiens. GOMF and KEGG enrichment analyses of the predicted targets revealed that "oxidoreductase activity" was among the top enriched terms in both yeast and human cells. These suggested a potential regulation of oxidative stress response (OSR) by NLE. RNA-seq analysis of NLE-treated yeast corroborated the anti-oxidative effect, with "oxidoreductase activity" and "oxidation-reduction process" ranking high in enriched GO terms. Notably, CTT1, encoding catalase, emerged as the most significantly up-regulated gene within the "oxidoreductase activity" cluster. In a ctt1 null mutant, the enhanced oxidative stress resistance and extended lifespan induced by NLE were nullified. For human cells, NLE pretreatment demonstrated a decrease in reactive oxygen species levels and senescence-associated β-galactosidase activity in HeLa cells, indicative of anti-aging and anti-oxidative effects. This study unveils the anti-aging and anti-oxidative properties of NLE while delving into their mechanisms, providing novel insights for pharmacological interventions in aging using phytochemicals.

Exploring the immunomodulatory potential of Brahmi (Bacopa monnieri) in the treatment of invasive ductal carcinoma

Bacopa monnieri (L) Wettst, commonly known as Brahmi, stands as a medicinal plant integral to India's traditional medical system, Ayurveda, where it is recognized as a "medhya rasayana"-a botanical entity believed to enhance intellect and mental clarity. Its significant role in numerous Ayurvedic formulations designed to address conditions such as anxiety, memory loss, impaired cognition, and diminished concentration underscores its prominence. Beyond its application in cognitive health, Brahmi has historically been employed in Ayurvedic practices for the treatment of inflammatory diseases, including arthritis. In contemporary biomedical research, Bacopa monnieri can attenuate the release of pro-inflammatory cytokines TNF-α and IL-6 in animal models. However, there remains a paucity of information regarding Bacopa's potential as an anticancer agent, warranting further investigation in this domain. Based on previous findings with Brahmi (Bacopa monnieri), the current study aims to find out the role of Brahmi plant preparation (BPP) in immunomodulatory actions on IDC. Employing a specific BPP concentration, we conducted a comprehensive study using MTT assay, ELISA, DNA methylation analysis, Western blotting, ChIP, and mRNA profiling to assess BPP's immunomodulatory properties. Our research finding showed the role of BPP in augmenting the action of T helper 1 (TH1) cells which secreted interferon-γ (IFN-γ) which in turn activated cytotoxic T-lymphocytes (CTL) to kill the cells of IDC (*p < 0.05). Moreover, we found out that treatment with BPP not only increased the activities of tumor-suppressor genes (p53 and BRCA1) but also decreased the activities of oncogenes (Notch1 and DNAPKcs) in IDC (*p < 0.05). BPP had an immense significance in controlling the epigenetic dysregulation in IDC through the downregulation of Histone demethylation & Histone deacetylation and upregulation of Histone methylation and Histone acetylation (*p < 0.05). Our Chromatin immunoprecipitation (ChIP)-qPCR data showed BPP treatment increased percentage enrichment of STAT1 & BRCA1 (*p < 0.05) and decreased percentage enrichment of STAT3, STAT5 & NF ΚB (*p < 0.05) on both TBX21 and BRCA1 gene loci in IDC. In addition, BPP treatment reduced the hypermethylation of the BRCA1-associated-DNA, which is believed to be a major factor in IDC (*p < 0.05). BPP not only escalates the secretion of type 1 specific cytokines but also escalates tumor suppression and harmonizes various epigenetic regulators and transcription factors associated with Signal Transducer and Activator of Transcription (STAT) to evoke tumor protective immunity in IDC.

The immunomodulatory impact of naturally derived neem leaf glycoprotein on the initiation progression model of 4NQO induced murine oral carcinogenesis: a preclinical study

Introduction

Murine tumor growth restriction by neem leaf glycoprotein (NLGP) was established in various transplanted models of murine sarcoma, melanoma and carcinoma. However, the role of NLGP in the sequential carcinogenic steps has not been explored. Thus, tongue carcinogenesis in Swiss mice was induced by 4-nitroquinoline-1-oxide (4NQO), which has close resemblance to human carcinogenesis process. Interventional role of NLGP in initiation-promotion protocol established during 4NQO mediated tongue carcinogenesis in relation to systemic immune alteration and epithelial-mesenchymal transition (EMT) is investigated.

Methods

4NQO was painted on tongue of Swiss mice every third day at a dose of 25µl of 5mg/ml stock solution. After five consecutive treatment with 4NQO (starting Day7), one group of mice was treated with NLGP (s.c., 25µg/mice/week), keeping a group as PBS control. Mice were sacrificed in different time-intervals to harvest tongues and studied using histology, immunohistochemistry, flow-cytometry and RT-PCR on different immune cells and EMT markers (e-cadherin, vimentin) to elucidate their phenotypic and secretory status.

Results

Local administration of 4NQO for consecutive 300 days promotes significant alteration in tongue mucosa including erosion in papillae and migration of malignant epithelial cells to the underlying connective tissue stroma with the formation of cell nests (exophytic-hyperkeratosis with mild dysplasia). Therapeutic NLGP treatment delayed pre-neoplastic changes promoting normalization of mucosa by maintaining normal structure. Flow-cytometric evidences suggest that NLGP treatment upregulated CD8+, IFNγ+, granzyme B+, CD11c+ cells in comparison to 4NQO treated mice with a decrease in Ki67+ and CD4+FoxP3+ cells in NLGP treated cohort. RT-PCR demonstrated a marked reduction of MMP9, IL-6, IL-2, CD31 and an upregulation in CCR5 in tongues from 4NQO+NLGP treated mice in comparison to 4NQO treated group. Moreover, 4NQO mediated changes were associated with reduction of e-cadherin and simultaneous up-regulation of vimentin expression in epithelium that was partially reversed by NLGP.

Discussion

Efficacy of NLGP was tested first time in sequential carcinogenesis model and proved effective in delaying the initial progression. NLGP normalizes type 1 immunity including activation of the CD8+T effector functions, reduction of regulatory T cell functions, along with changes in EMT to make the host systemically alert to combat the carcinogenic threat.

COVID-19 imparted immune manifestation can be combated by NLGP: Lessons from cancer research

SARS-CoV-2 easily infects human monocytes, macrophages and possibly dendritic cells (DCs), causing dysfunctions of these important antigen presenting cells (APCs). Observed DC dysfunctions facilitate improper antigen presentation, which obviously results T cell anergy, exhaustion and apoptosis, thus, may be contributing significantly in SARS-CoV-2 infection associated lymphopenia. Neem Leaf Glycoprotein or NLGP has enormous role in altered DC functions, thereby, offering optimum T cell mediated cytotoxicity, as experienced from cancer system. Such NLGP guided correction of altered DCs might also be effective to generate proper SARS-CoV-2-specific effector and central memory T cells.

Role of interferon-gamma (IFN-γ) and IFN-γ receptor 1/2 (IFNγR1/2) in regulation of immunity, infection, and cancer development: IFN-γ-dependent or independent pathway

IFN-γ, a soluble cytokine being produced by T lymphocytes, macrophages, mucosal epithelial cells, or natural killer cells, is able to bind to the IFN-γ receptor (IFNγR) and in turn activate the Janus kinase (JAK)-signal transducer and transcription protein (STAT) pathway and induce expression of IFN-γ-stimulated genes. IFN-γ is critical for innate and adaptive immunity and aberrant IFN-γ expression and functions have been associated with different human diseases. However, the IFN-γ/IFNγR signaling could be a double-edged sword in cancer development because the tissue microenvironments could determine its anti- or pro-tumorigenic activities. The IFNγR protein consists of two IFNγR1 and IFNγR2 chains, subunits of which play different roles under certain conditions. This review assessed IFNγR polymorphisms, expression and functions in development and progression of various human diseases in an IFN-γ-dependent or independent manner. This review also discussed tumor microenvironment, microbial infection, and vital molecules in the IFN-γ upstream signaling that might regulate IFNγR expression, drug resistance, and druggable strategy, to provide evidence for further application of IFNγR.

NLGP regulates RGS5-TGFβ axis to promote pericyte-dependent vascular normalization during restricted tumor growth

Altered RGS5-associated intracellular pericyte signaling and its abnormal crosstalk with endothelial cells (ECs) result chaotic tumor-vasculature, prevent effective drug delivery, promote immune-evasion and many more to ensure ultimate tumor progression. Moreover, the frequency of lethal-RGS5^high  pericytes within tumor was found to increase with disease progression, which signifies the presence of altered cell death pathway within tumor microenvironment (TME). In this study, we checked whether and how neem leaf glycoprotein (NLGP)-immunotherapy-mediated tumor growth restriction is associated with modification of pericytes' signaling, functions and its interaction with ECs. Analysis of pericytes isolated from tumors of NLGP treated mice suggested that NLGP treatment promotes apoptosis of NG2⁺ RGS5^high -fuctionally altered pericytes by downregulating intra-tumoral TGFβ, along with maintenance of more matured RGS5^neg  pericytes. NLGP-mediated inhibition of TGFβ within TME rescues binding of RGS5 with Gαi and thereby termination of PI3K-AKT mediated survival signaling by downregulating Bcl2 and initiating pJNK mediated apoptosis. Limited availability of TGFβ also prevents complex-formation between RGS5 and Smad2 and rapid RGS5 nuclear translocation to mitigate alternate immunoregulatory functions of RGS5^high  tumor-pericytes. We also observed binding of Ang1 from pericytes with Tie2 on ECs in NLGP-treated tumor, which support re-association of pericytes with endothelium and subsequent vessel stabilization. Furthermore, NLGP-therapy- associated RGS5 deficiency relieved CD4⁺  and CD8⁺ T cells from anergy by regulating 'alternate-APC-like' immunomodulatory characters of tumor-pericytes. Taken together, present study described the mechanisms of NLGP's effectiveness in normalizing tumor-vasculature by chiefly modulating pericyte-biology and EC-pericyte interactions in tumor-host to further strengthen its translational potential as single modality treatment.

Notch1/TAZ axis promotes aerobic glycolysis and immune escape in lung cancer

Oncogenic signaling pathway reprograms cancer cell metabolism to promote aerobic glycolysis in favor of tumor growth. The ability of cancer cells to evade immunosurveillance and the role of metabolic regulators in T-cell functions suggest that oncogene-induced metabolic reprogramming may be linked to immune escape. Notch1 signaling, dysregulated in lung cancer, is correlated with increased glycolysis. Herein, we demonstrate in lung cancer that Notch1 promotes glycolytic gene expression through functional interaction with histone acetyltransferases p300 and pCAF. Notch1 signaling forms a positive feedback loop with TAZ. Notch1 transcriptional activity was increased in the presence of TAZ and the activation was TEAD1 independent. Notably, aerobic glycolysis was critical for Notch1/TAZ axis modulation of lung cancer growth in vitro and in vivo. Increased level of extracellular lactate via Notch1/TAZ axis inhibited cytotoxic T-cell activity, leading to the invasive characteristic of lung cancer cells. Interaction between Notch1 and TAZ promoted aerobic glycolysis and immune escape in lung cancer. Our findings provide potential therapeutic targets against Notch1 and TAZ and would be important for clinical translation in lung cancer.

Immunological Mechanism and Clinical Application of PAMP Adjuvants

BACKGROUND

The host innate immune system can recognize Pathogen-Associated Molecular Patterns (PAMPs) through Pattern Recognition Receptors (PRRs), thereby initiating innate immune responses and subsequent adaptive immune responses. PAMPs can be developed as a vaccine adjuvant for modulating and optimizing antigen-specific immune responses, especially in combating viral infections and tumor therapy. Although several PAMP adjuvants have been successfully developed they are still lacking in general, and many of them are in the preclinical exploration stage.

OBJECTIVE

This review summarizes the research progress and development direction of PAMP adjuvants, focusing on their immune mechanisms and clinical applications.

METHODS

PubMed, Scopus, and Google Scholar were screened for this information. We highlight the immune mechanisms and clinical applications of PAMP adjuvants.

RESULTS

Because of the differences in receptor positions, specific immune cells targets, and signaling pathways, the detailed molecular mechanism and pharmacokinetic properties of one agonist cannot be fully generalized to another agonist, and each PAMP should be studied separately. In addition, combination therapy and effective integration of different adjuvants can increase the additional efficacy of innate and adaptive immune responses.

CONCLUSION

The mechanisms by which PAMPs exert adjuvant functions are diverse. With continuous discovery in the future, constant adjustments should be made to build new understandings. At present, the goal of therapeutic vaccination is to induce T cells that can specifically recognize and eliminate tumor cells and establish long-term immune memory. Following immune checkpoint modulation therapy, cancer treatment vaccines may be an option worthy of clinical testing.

Neem leaf glycoprotein reverses tumor-induced and age-associated thymic involution to maintain peripheral CD8+ T cell pool

Aim: As tumor causes atrophy in the thymus to target effector-T cells, this study is aimed to decipher the efficacy of neem leaf glycoprotein (NLGP) in tumor- and age-associated thymic atrophy. Materials & methods: Different thymus parameters were studied using flow cytometry, reverse transcriptase PCR and immunocyto-/histochemistry in murine melanoma and sarcoma models. Results: Longitudinal NLGP therapy in tumor hosts show tumor-reduction along with significant normalization of thymic alterations. NLGP downregulates intrathymic IL-10, which eventually promotes Notch1 to rescue blockade in CD25⁺CD44⁺c-Kit⁺DN2 to CD25⁺CD44^-c-Kit^-DN3 transition in T cell maturation and suppress Ikaros/IRF8/Pu.1 to prevent DN2-T to DC differentiation in tumor hosts. The CD5^intTCRαβ^high DP3 population was also increased to endorse CD8⁺ T cell generation. Conclusion: NLGP rescues tumor-induced altered thymic events to generate more effector T cells to restrain tumor.

A review of the anticancer activity of Azadirachta indica (Neem) in oral cancer

Background

Azadirachta indica (neem), belongs to the family of Meliaceae plants, is found in the Indian subcontinent. The neem tree is colloquially referred to as the village pharmacy due to its array of biological properties. Every part of the neem tree like its bark, leaves, sap, fruit, seeds, and twigs find a multitude of uses. It is customary to use them for management of skin diseases and various other infections.The anticancer properties of neem have been studied in the past and these include its ability to modulate the tumour environment, increase the cytotoxic ability of host monocytes and suppress the proliferation of tumour cells. The present review was conducted with the objective of scrutinizing and assimilating data about the usefulness Azadirachta indica in oral cancer from all the previously done work.

Material and methods

A planned review was conducted of all the studies that investigated the role of Azadirachta indica in oral cancer. Literature search was carried out using PubMed, Scopus and Google scholar databases. In addition to electronic searching, hand searching, cross referencing and various internet engines were also used to collect data. The articles were perused and articles not pertinent to our search were omitted.

Results and conclusion

The anticancer properties of neem were evaluated and the active constituents of neem have been demonstrated to unequivocally have preventive and therapeutic potential against oral cancer. Although, greater exploration of the anticancer properties of neem are required in order to effectively integrate it into the routine management of oral cancer.

Neem leaf glycoprotein prevents post-surgical sarcoma recurrence in Swiss mice by differentially regulating cytotoxic T and myeloid-derived suppressor cells

Post-surgical tumor recurrence is a common problem in cancer treatment. In the present study, the role of neem leaf glycoprotein (NLGP), a novel immunomodulator, in prevention of post-surgical recurrence of solid sarcoma was examined. Data suggest that NLGP prevents tumor recurrence after surgical removal of sarcoma in Swiss mice and increases their tumor-free survival time. In NLGP-treated tumor-free mice, increased cytotoxic CD8⁺ T cells and a decreased population of suppressor cells, especially myeloid-derived suppressor cells (MDSCs) was observed. NLGP-treated CD8⁺ T cells showed greater cytotoxicity towards tumor-derived MDSCs and supernatants from the same CD8⁺ T cell culture caused upregulation of FasR and downregulation of cFLIP in MDSCs. To elucidate the role of CD8⁺ T cells, specifically in association with the downregulation in MDSCs, CD8⁺ T cells were depleted in vivo before NLGP immunization in surgically tumor removed mice and tumor recurrence was noted. These mice also exhibited increased MDSCs along with decreased levels of Caspase 3, Caspase 8 and increased cFLIP expression. In conclusion, it can be stated that NLGP, by activating CD8⁺ T cells, down regulates the proportion of MDSCs. Accordingly, suppressive effects of MDSCs on CD8⁺ T cells are minimized and optimum immune surveillance in tumor hosts is maintained to eliminate the residual tumor mass appearing during recurrence.

Neem tree (Azadirachta indica) extract specifically suppresses the growth of tumors in H22-bearing Kunming mice

Recently, neem tree (Azadirachta indica) extract (NTE) has been reported to have various antitumor activities against gastric, breast, prostate, and skin cancer, respectively. The current study was designed to evaluate the effect of NTE on hepatic cancer in a mouse model. The possible side effects elicited by NTE were also evaluated. The components in NTE were analyzed by liquid chromatography–mass spectrometry (LC-MS). H22 cells-bearing Kumming mice were generated by injecting H22 cells subcutaneously into the right forelimb armpit of the mice. Then the mice were treated daily for 27 days with NTE (150, 300, and 600 mg/kg body weight) by intragastric administration, using carboxymethyl cellulose (CMC, 1%) as blank control and cyclophosphamide (CTX, 20 mg/kg) as positive control. The antitumor effect of NTE was evaluated by assessment of survival rate, body weight, tumor volume and weight, tumor histology, thymus and spleen indexes, and liver histology. The tumor weight and volume in groups of NTE and CTX were significantly lower than those in the CMC group. The survival rate in the NTE group receiving the high dose (600 mg/kg) was significantly higher than that in the CTX and CMC groups. Compared with CTX, NTE was observed to have a tumor-specific cytotoxicity without impairing the normal liver tissue. Additionally, the higher indexes of thymus and spleen indicated that NTE could facilitate the growth of immune organs. The results indicate that NTE is a promising candidate for the antitumor treatment with high efficacy and safety.

Neem leaf glycoprotein prophylaxis transduces immune dependent stop signal for tumor angiogenic switch within tumor microenvironment

We have reported that prophylactic as well as therapeutic administration of neem leaf glycoprotein (NLGP) induces significant restriction of solid tumor growth in mice. Here, we investigate whether the effect of such pretreatment (25µg/mice; weekly, 4 times) benefits regulation of tumor angiogenesis, an obligate factor for tumor progression. We show that NLGP pretreatment results in vascular normalization in melanoma and carcinoma bearing mice along with downregulation of CD31, VEGF and VEGFR2. NLGP pretreatment facilitates profound infiltration of CD8+ T cells within tumor parenchyma, which subsequently regulates VEGF-VEGFR2 signaling in CD31+ vascular endothelial cells to prevent aberrant neovascularization. Pericyte stabilization, VEGF dependent inhibition of VEC proliferation and subsequent vascular normalization are also experienced. Studies in immune compromised mice confirmed that these vascular and intratumoral changes in angiogenic profile are dependent upon active adoptive immunity particularly those mediated by CD8+ T cells. Accumulated evidences suggest that NLGP regulated immunomodulation is active in tumor growth restriction and normalization of tumor angiogenesis as well, thereby, signifying its clinical translation.

Murine carcinoma expressing carcinoembryonic antigen-like protein is restricted by antibody against neem leaf glycoprotein

We have generated a polyclonal antibody against a novel immunomodulator, neem leaf glycoprotein (NLGP) that can react to a specific 47 kDa subunit of NLGP. Generated anti-NLGP antibody (primarily IgG2a) was tested for its anti-tumor activity in murine carcinoma (EC, CT-26), sarcoma (S180) and melanoma (B16Mel) tumor models. Surprisingly, tumor growth restriction was only observed in CT-26 carcinoma models, without any alteration in other tumor systems. Comparative examination of antigenicity between four different tumor models revealed high expression of CEA-like protein on the surface of CT-26 tumors. Subsequent examination of the cross-reactivity of anti-NLGP antibody with purified or cell bound CEA revealed prominent recognition of CEA by anti-NLGP antibody, as detected by ELISA, Western Blotting and immunohistochemistry. This recognition seems to be responsible for anti-tumor function of anti-NLGP antibody only on CEA-like protein expressing CT-26 tumor models, as confirmed by ADCC reaction in CEA(+) tumor systems where dependency to anti-NLGP antibody is equivalent to anti-CEA antibody. Obtained result with enormous therapeutic potential for CEA(+) tumors may be explained in view of the epitope spreading concept, however, further investigation is crucial.

Immunotherapeutic targeting of established sarcoma in Swiss mice by tumor-derived antigen-pulsed NLGP matured dendritic cells is CD8+ T-cell dependent

Aim: Neem leaf glycoprotein (NLGP) matures human myeloid and mouse bone marrow-derived dendritic cells (DCs). (NLGP) also therapeutically restricts the mouse established sarcoma growth by activating CD8+ T cells along with increased proportion of tumor residing CD11c+ DCs. Here, we intended to find out whether CD8+ T cells become cytotoxic to sarcoma cells after presentation of sarcoma antigen by NLGP-matured DCs to restrict murine sarcoma growth. Materials & methods: NLGP was prepared from matured neem(Azadirachta indica) leaves. Solid sarcoma tumor in Swiss mice was developed by subcutaneous inoculation of sarcoma cells. GMCSF-IL-4 generated DCs were matured with NLGP and pulsed with sarcoma antigen for immunotherapy. Status of CD8+CD69+T cells was studied by flow cytometry and secretion of cytokines was measured by ELISA. RT-PCR was used to monitor the status of perforin, granzyme B. Results: NLGP-matured sarcoma antigen-pulsed DCs (DCNLGPTAg) inhibit mouse sarcoma growth. DCNLGPTAg immunization enhances CD8+ T-cell number within tumor-infiltrating lymphocytes and tumor-draining lymph nodes along with increased perforin and granzyme B expression. Antigen-specific T-cell proliferation and IFN-γ secretion were significantly higher in DCNLGP- and DCNLGPTAg-immunized mice groups. In vivo CD8+ T-cell depletion abrogated the DCNLGPTAg-mediated tumor growth restriction. Conclusion: DCNLGPTAg restricts CD8+ T-cell-dependent mouse established sarcoma growth, related to the optimum antigen presentation by DCs to CD8+ T cells.

Preclinical evaluation of the supercritical extract of azadirachta indica (neem) leaves in vitro and in vivo on inhibition of prostate cancer tumor growth

Azadirachta indica, commonly known as neem, has gained worldwide prominence because of its medical properties, namely antitumor, antiviral, anti-inflammatory, antihyperglycemic, antifungal, and antibacterial activities. Despite these promising results, gaps remain in our understanding of the molecular mechanism of action of neem compounds and their potential for use in clinical trials. We investigated supercritical extract of neem leaves (SENL) for the following: molecular targets in vitro, in vivo efficacy to inhibit tumor growth, and bioactive compounds that exert antitumor activity. Treatment of LNCaP-luc2 prostate cancer cells with SENL suppressed dihydrotestosterone-induced androgen receptor and prostate-specific antigen levels. SENL inhibited integrin β1, calreticulin, and focal adhesion kinase activation in LNCaP-luc2 and PC3 prostate cancer cells. Oral administration of SENL significantly reduced LNCaP-luc2 xenograft tumor growth in mice with the formation of hyalinized fibrous tumor tissue, reduction in the prostate-specific antigen, and increase in AKR1C2 levels. To identify the active anticancer compounds, we fractionated SENL by high-pressure liquid chromatography and evaluated 16 peaks for cytotoxic activity. Four of the 16 peaks exhibited significant cytotoxic activity against prostate cancer cells. Mass spectrometry of the isolated peaks suggested the compounds with cytotoxic activity were nimbandiol, nimbolide, 2',3'-dihydronimbolide, and 28-deoxonimbolide. Analysis of tumor tissue and plasma samples from mice treated with SENL indicated 28-deoxonimbolide and nimbolide as the bioactive compounds. Overall, our data revealed the bioactive compounds in SENL and suggested that the anticancer activity could be mediated through alteration in androgen receptor and calreticulin levels in prostate cancer.

Normalization of tumor microenvironment by neem leaf glycoprotein potentiates effector T cell functions and therapeutically intervenes in the growth of mouse sarcoma

We have observed restriction of the murine sarcoma growth by therapeutic intervention of neem leaf glycoprotein (NLGP). In order to evaluate the mechanism of tumor growth restriction, here, we have analyzed tumor microenvironment (TME) from sarcoma bearing mice with NLGP therapy (NLGP-TME, in comparison to PBS-TME). Analysis of cytokine milieu within TME revealed IL-10, TGFβ, IL-6 rich type 2 characters was switched to type 1 microenvironment with dominance of IFNγ secretion within NLGP-TME. Proportion of CD8(+) T cells was increased within NLGP-TME and these T cells were protected from TME-induced anergy by NLGP, as indicated by higher expression of pNFAT and inhibit related downstream signaling. Moreover, low expression of FasR(+) cells within CD8(+) T cell population denotes prevention from activation induced cell death. Using CFSE as a probe, better migration of T cells was noted within TME from NLGP treated mice than PBS cohort. CD8(+) T cells isolated from NLGP-TME exhibited greater cytotoxicity to sarcoma cells in vitro and these cells show higher expression of cytotoxicity related molecules, perforin and granzyme B. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of sarcoma in vivo. Such tumor growth inhibition by NLGP-TME exposed T cells was not observed when mice were depleted for CD8(+) T cells. Accumulated evidences strongly suggest NLGP mediated normalization of TME allows T cells to perform optimally to inhibit the tumor growth.

Neem leaf glycoprotein is superior than cisplatin and sunitinib malate in restricting melanoma growth by normalization of tumor microenvironment

We have observed earlier that therapeutic treatment with neem leaf glycoprotein (NLGP) inhibits murine B16-melanoma growth in vivo and improves survivability of treated mice. Anti-tumor effect of NLGP is directly associated with enhanced CD8(+) T cell activity and downregulation of suppressive cellular functions. Objective of this present study is to know the efficacy of NLGP in comparison to two popular drugs, Cisplatin and Sunitinib malate (Sutent) in relation to the modulation of tumor microenvironment (TME). Analysis of cytokine milieu within TME revealed IL-10, TGFβ, IL-6 rich type 2 characters was significantly switched to type 1 microenvironment with dominance of IFNγ and IL-2 within NLGP-TME, which was not found in other cases; however Cisplatin-TME appeared better in type 2 to type 1 conversion than Sutent-TME as evidenced by RT-PCR, ELISA and immunohistochemical analysis. NLGP-TME educated CD8(+) T cells exhibited greater cytotoxicity to B16 Melanoma cells in vitro and these cells showed comparatively higher expression of cytotoxicity related molecules, perforin and granzyme B than Cisplatin-TME and Sutent-TME educated T cells. Adoptive transfer of NLGP-TME exposed T cells, but not PBS-TME exposed cells in mice, is able to significantly inhibit the growth of melanoma in vivo. Such tumor growth inhibition was in significantly lower extent when therapeutic CD8(+) T cells were exposed to either Cisplatin-TME or Sutent-TME or control-TME. Accumulated evidences strongly suggest that non toxic NLGP normalized TME allows T cells to perform optimally than other TMEs under study to inhibit the melanoma growth.

Neem leaf glycoprotein overcomes indoleamine 2,3 dioxygenase mediated tolerance in dendritic cells by attenuating hyperactive regulatory T cells in cervical cancer stage IIIB patients

Tolerogenic dendritic cells (DCs) are a subset of DCs characterized by abundant indoleamine 2,3 dioxygenase (IDO) expressions. IDO may be co-operatively induced in DCs by regulatory T (Tregs) cells and various DC maturation agents. Tregs are markedly amplified in the physiological system of cancer patients, inducing over tolerance in DCs that leads to the hyper accumulation of immunosuppressive IDO in tumor microenvironment, thereby, hampering anti-tumor immunity. Consequently, a major focus of current immunotherapeutic strategies in cancer is to minimize IDO, which is possible by reducing Tregs and using various IDO inhibitors. Neem leaf glycoprotein (NLGP), a natural and nontoxic immunomodulator, demonstrated several unique immunoregulatory activities. Noteworthy activities of NLGP are to mature DCs and to inhibit Tregs. As Tregs are inducer of IDO in DCs and hyperactive Tregs is a hallmark of cancer, we anticipated that NLGP might abrogate IDO induction in DCs by inhibiting Tregs. Evidences are presented here that in a co-culture of DCs and Tregs isolated from cervical cancer stage IIIB (CaCx-IIIB) patients, NLGP does inhibit IDO induction in DCs by curtailing the over expression of Cytotoxic T-Lymphocyte Antigen 4 (CTLA4) on Tregs and concomitantly induces optimal DC maturation. In contrast, in the presence of LPS as maturation agent the DCs displays a tolerogenic profile. This finding suggests the reduction of tolerogenecity of DCs in CaCx-IIIB patients by reducing the IDO pool using NLGP. Accordingly, this study sheds more light on the diverse immunomodulatory repertoire of NLGP.

Neem leaf glycoprotein activates CD8(+) T cells to promote therapeutic anti-tumor immunity inhibiting the growth of mouse sarcoma

In spite of sufficient data on Neem Leaf Glycoprotein (NLGP) as a prophylactic vaccine, little knowledge currently exists to support the use of NLGP as a therapeutic vaccine. Treatment of mice bearing established sarcomas with NLGP (25 µg/mice/week subcutaneously for 4 weeks) resulted in tumor regression or dormancy (Tumor free/Regressor, 13/24 (NLGP), 4/24 (PBS)). Evaluation of CD8⁺ T cell status in blood, spleen, TDLN, VDLN and tumor revealed increase in cellular number. Elevated expression of CD69, CD44 and Ki67 on CD8⁺ T cells revealed their state of activation and proliferation by NLGP. Depletion of CD8⁺ T cells in mice at the time of NLGP treatment resulted in partial termination of tumor regression. An expansion of CXCR3⁺ and CCR5⁺ T cells was observed in the TDLN and tumor, along with their corresponding ligands. NLGP treatment enhances type 1 polarized T-bet expressing T cells with downregulation of GATA3. Treg cell population was almost unchanged. However, T∶Treg ratios significantly increased with NLGP. Enhanced secretion/expression of IFNγ was noted after NLGP therapy. In vitro culture of T cells with IL-2 and sarcoma antigen resulted in significant enhancement in cytotoxic efficacy. Consistently higher expression of CD107a was also observed in CD8⁺ T cells from tumors. Reinoculation of sarcoma cells in tumor regressed NLGP-treated mice maintained tumor free status in majority. This is correlated with the increment of CD44^hiCD62L^hi central memory T cells. Collectively, these findings support a paradigm in which NLGP dynamically orchestrates the activation, expansion, and recruitment of CD8⁺ T cells into established tumors to operate significant tumor cell lysis.

Neem leaf glycoprotein is nontoxic to physiological functions of Swiss mice and Sprague Dawley rats: histological, biochemical and immunological perspectives

We have evaluated the toxicity profile of a unique immunomodulator, neem leaf glycoprotein (NLGP) on different physiological systems of Swiss mice and Sprague Dawley rats. NLGP injection, even in higher doses than effective concentration caused no behavioral changes in animals and no death. NLGP injection increased the body weights of mice slightly without any change in organ weights. NLGP showed no adverse effect on the hematological system. Moreover, little hematostimulation was noticed, as evidenced by increased hemoglobin content, leukocyte count and lymphocyte numbers. Histological assessment of different organs revealed no alterations in the organ microstructure of the NLGP treated mice and rats. Histological normalcy of liver and kidney was further confirmed by the assessment of liver enzymes like alkaline phosphatase, SGOT, SGPT and nephrological products like urea and creatinine. NLGP has no apoptotic effect on immune cells but induces proliferation of mononuclear cells collected from mice and rats. Number of CD4(+), CD8(+) T cells, DX5(+) NK cells, CD11b(+) macrophages and CD11c(+) dendritic cells is upregulated by NLGP without a significant change in CD4(+)CD25(+)Foxp3(+) regulatory T cells. Type 1 cytokines, like IFNγ also increased in serum with a decrease in type 2 cytokines. Total IgG content, especially IgG2a increased in NLGP treated mice. These type 1 directed changes help to create an anti-tumor immune environment that results in the restriction of carcinoma growth in mice. Accumulated evidence strongly suggests the non-toxic nature of NLGP. Thus, it can be recommended for human use in anti-cancer therapy.

Antiangiogenic Effects and Therapeutic Targets of Azadirachta indica Leaf Extract in Endothelial Cells

Azadirachta indica (common name: neem) leaves have been found to possess immunomodulatory, anti-inflammatory and anti-carcinogenic properties. The present study evaluates anti-angiogenic potential of ethanol extract of neem leaves (EENL) in human umbilical vein endothelial cells (HUVECs). Treatment of HUVECs with EENL inhibited VEGF induced angiogenic response in vitro and in vivo. The in vitro proliferation, invasion and migration of HUVECs were suppressed with EENL. Nuclear fragmentation and abnormally small mitochondria with dilated cristae were observed in EENL treated HUVECs by transmission electron microscopy. Genome-wide mRNA expression profiling after treatment with EENL revealed differentially regulated genes. Expression changes of the genes were validated by quantitative real-time polymerase chain reaction. Additionally, increase in the expression of HMOX1, ATF3 and EGR1 proteins were determined by immunoblotting. Analysis of the compounds in the EENL by mass spectrometry suggests the presence of nimbolide, 2',3'-dehydrosalannol, 6-desacetyl nimbinene and nimolinone. We further confirmed antiproliferative activity of nimbolide and 2',3'-dehydrosalannol in HUVECs. Our results suggest that EENL by regulating the genes involved in cellular development and cell death functions could control cell proliferation, attenuate the stimulatory effects of VEGF and exert antiangiogenic effects. EENL treatment could have a potential therapeutic role during cancer progression.

Neem leaf glycoprotein inhibits CD4+CD25+Foxp3+ Tregs to restrict murine tumor growth

Background: The presence of Tregs in tumors is associated with compromised tumor-specific immune responses and has a clear negative impact on survival of cancer patients. Thus, downregulation of Tregs is considered as a promising cancer immunotherapeutic approach. We have reported previously that neem leaf glycoprotein (NLGP) prophylaxis restricts tumor growth in mice by immune activation. In continuation, here, involvement of NLGP in the modulation of Tregs in association with tumor growth restriction is investigated. Results: NLGP downregulates CD4+CD25+Foxp3+ Tregs within tumors. NLGP-mediated downregulation of CCR4 along with its ligand CCL22 restricts Treg migration at the tumor site. NLGP is not apoptotic to Tregs but significantly downregulates the expression of Foxp3, CTLA4 and GITR. It also reverses the functional impairment of T-effector cells by Tregs, in terms of IFN-γ secretion, cellular proliferation and tumor cell cytotoxicity. NLGP also facilitates reconditioning of tumor microenvironment (hostile) by increasing IFN-γ and IL-12 but decreasing IL-10, TGF-β, VEGF and IDO, creating an antitumor niche. Interaction between Foxp3, p-NFATc3 and p-Smad2/3, needed for successful Treg function, is also inhibited by NLGP. Conclusion: All of these coordinated events might result in inhibition of Treg associated-tumor growth and therefore increased survivability of mice having NLGP treatment before or/and after tumor inoculation. Thus, the possibility of NLGP being an excellent tool as a T-cell anergy breaker by abrogating the suppressor functions of Tregs in cancer needs to be explored further in the clinic.

Novel molecular targets of Azadirachta indica associated with inhibition of tumor growth in prostate cancer

Advanced prostate cancer has significant long-term morbidity, and there is a growing interest in alternative and complimentary forms of therapy that will improve the outcomes of patients. Azadirachta indica (common name: neem) contains multiple active compounds that have potent anti-inflammatory and anticancer properties. The present study investigates the novel targets of the anticancer activity of ethanol extract of neem leaves (EENL) in vitro and evaluates the in vivo efficacy in the prostate cancer models. Analysis of the components in the EENL by mass spectrometry suggests the presence of 2′,3′-dehydrosalannol, 6-desacetyl nimbinene, and nimolinone. Treatment of C4-2B and PC-3M-luc2 prostate cancer cells with EENL inhibited the cell proliferation. Genome-wide expression profiling, using oligonucleotide microarrays, revealed genes differentially expressed with EENL treatment in prostate cancer cells. Functional analysis unveiled that most of the up-regulated genes were associated with cell death, and drug metabolism, and the down-regulated genes were associated with cell cycle, DNA replication, recombination, and repair functions. Quantitative PCR confirmed significant up-regulation of 40 genes and immunoblotting revealed increase in the protein expression levels of HMOX1, AKR1C2, AKR1C3, and AKR1B10. EENL treatment inhibited the growth of C4-2B and PC-3M-luc2 prostate cancer xenografts in nude mice. The suppression of tumor growth is associated with the formation of hyalinized fibrous tumor tissue and the induction of cell death by apoptosis. These results suggest that EENL-containing natural bioactive compounds could have potent anticancer property and the regulation of multiple cellular pathways could exert pleiotrophic effects in prevention and treatment of prostate cancer.

Neem leaf glycoprotein partially rectifies suppressed dendritic cell functions and associated T cell efficacy in patients with stage IIIB cervical cancer

Myeloid-derived dendritic cells (DCs) generated from monocytes obtained from stage IIIB cervical cancer (CaCx IIIB) patients show dysfunctional maturation; thus, antitumor T cell functions are dysregulated. In an objective to optimize these dysregulated immune functions, the present study is focused on the ability of neem leaf glycoprotein (NLGP), a nontoxic preparation of the neem leaf, to induce optimum maturation of dendritic cells from CaCx IIIB patients. In vitro NLGP treatment of immature DCs (iDCs) obtained from CaCx IIIB patients results in upregulated expression of various cell surface markers (CD40, CD83, CD80, CD86, and HLA-ABC), which indicates DC maturation. Consequently, NLGP-matured DCs displayed balanced cytokine secretions, with type 1 bias and noteworthy functional properties. These DCs displayed substantial T cell allostimulatory capacity and promoted the generation of cytotoxic T lymphocytes (CTLs). Although NLGP-matured DCs derived from CaCx monocytes are generally subdued compared to those with a healthy monocyte origin, considerable revival of the suppressed DC-based immune functions is noted in vitro at a fairly advanced stage of CaCx, and thus, further exploration of ex vivo and in vivo DC-based vaccines is proposed. Moreover, the DC maturating efficacy of NLGP might be much more effective in the earlier stages of CaCx, where the extent of immune dysregulation is less and, thus, the scope of further investigation may be explored.

Restoration of dysregulated CC chemokine signaling for monocyte/macrophage chemotaxis in head and neck squamous cell carcinoma patients by neem leaf glycoprotein maximizes tumor cell cytotoxicity

Previous studies have shown that the CC chemokine receptor CCR5 is downregulated on monocyte/macrophage (MO/Mphi) surfaces in head and neck squamous cell carcinoma (HNSCC) patients (stage IIIB). Ligands (RANTES, MIP-1alpha and MIP-1beta) of this chemokine receptor were also secreted in lesser quantity from MO/Mphi of HNSCC patients in comparison with healthy individuals. In an aim to restore this dysregulated receptor-ligand signaling, we have used neem leaf glycoprotein (NLGP), a novel immunomodulator reported from our laboratory. NLGP upregulated CCR5 expression, as evidenced from studies on MO/Mphi of peripheral blood from HNSCC patients as well as healthy individuals. Expression of RANTES, MIP-1alpha and MIP-1beta was also upregulated following NLGP treatment of these cells in vitro. Interestingly, NLGP has little effect on the expression of CCR5 and the ligand RANTES in oral cancer cells. This restored CCR5 receptor-ligand signaling seen in MO/Mphi was reflected in improved CCR5-dependent, p38 mitogen-activated protein kinase (MAPK)-mediated migration of MO/Mphi after NLGP treatment to a standard chemoattractant. NLGP also induces better antigen presentation and simultaneous costimulation to effector T cells by MO/Mphi by upregulating human leucocyte antigen (HLA)-ABC, CD80 and CD86. In addition, NLGP-treated MO/Mphi-primed T cells can effectively lyse tumor cells in vitro. The effects of NLGP on monocyte migration and T cell-mediated oral tumor cell killing were further demonstrated in transwell assays with or without CCR5 neutralization. These results suggest a new approach in cancer immunotherapy by modulating dysregulated CCR5 signals from MO/Mphi.

Induction of type 1 cytokines during neem leaf glycoprotein assisted carcinoembryonic antigen vaccination is associated with nitric oxide production

Involvement of the nitric oxide (NO) release in CEAM phi NLGP (carcinoembryonic antigen pulsed macrophages with neem leaf glycoprotein) vaccination and its relationship with vaccine induced type 1 immune response were aimed to study in the present communication. Vaccination with CEAM phi NLGP resulted in macrophage activation as evidenced by its increased number and expression of CD69 marker. Activated macrophages demonstrated upregulation in synthesis of IL-12 and downregulation in IL-10, along with excess IFN gamma production in splenic cells, as evidenced from mRNA analysis. Induction of such type 1 immunity was further confirmed by expression of type 1 specific transcription factor, T-bet and enhancement of intracellular glutathione content. Such vaccination also induced greater nitric oxide (NO) production from macrophages. Dependence of induced type 1 immune response on the NO release and vice versa was studied by in vitro neutralization of IFN gamma/IL-12 and in vivo inhibition of NO production by methylene blue. Obtained results clearly demonstrated the interdependence of two anti-tumor immune functions, namely, NO production and generation of type 1 immune response. Understanding of the mechanism of this NO related immune modulation would have great impact in proposing CEAM phi NLGP vaccine in clinic for the treatment of CEA+ tumors.