A Monoclonal Antibody Against Neem Leaf Glycoprotein Recognizes Carcinoembryonic Antigen (CEA) and Restricts CEA Expressing Tumor Growth

Genotoxicity and maternal-fetal safety of the dried extract of leaves of Azadirachta indica A. Juss (Meliaceae) in Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Azadirachta indica A. Juss (Meliaceae), popularly known as "neem", is used for the treatment of rheumatism, cancer, ulcers, diabetes, respiratory problems, among others. This species is present on six continents and contains more than 400 bioactive compounds. Practically all parts of the plant are used in the treatment of diseases. Although it is widely used, no study has evaluated the safety of this species throughout the gestational period in Wistar rats.

AIM OF THE STUDY

To evaluate the genotoxicity and the effect of treatment with dried extract of leaves of Azadirachta indica on maternal toxicity and fetal development.

MATERIALS AND METHODS

The dried extract of leaves of A. indica was obtained by spray drying after percolation of the plant material in 30% ethanol (w/w). The total flavonoids and rutin contents of the extract were determined by spectrophotometric method and HPLC-DAD, respectively. Pregnant Wistar rats (n = 40) were divided into four groups (n = 10/group): one control and three groups treated with dried extract of leaves of A. indica at doses of 300, 600 or 1200 mg/kg. Treatments were carried out from gestational day (GD) 0-20. During gestation, clinical signs of toxicity, weight gain, feed and water consumption of the dams were evaluated. On GD 21, rats were euthanized and cardiac blood was collected. Liver, kidneys, lung, heart, uterus, ovaries and bone marrow were collected. Reproductive performance parameters, histopathological analysis, biochemistry and genotoxicity were evaluated. Fetuses were evaluated for external morphology, skeletal and visceral changes.

RESULTS

The total flavonoid content of the extract ranged from 2.64 to 3.01%, and the rutin content was 1.07%. There was no change in body mass gain, food and water consumption between the evaluated groups. There was also no difference between the groups in terms of biochemical parameters, reproductive performance, histopathological analysis of the mother's organs and genotoxicity. Supernumerary ossification sites of the sternum were observed, and other skeletal and visceral alterations were not significant.

CONCLUSIONS

The treatment did not induce maternal toxicity, it was neither embryotoxic nor fetotoxic. The extract was not potentially genotoxic, and at a dose of 1200 mg/kg, it caused changes in the ossification of the sternum.

Probe-integrated electrochemical immunosensor based on electrostatic nanocage array for reagentless and sensitive detection of tumor biomarker

Sensitive detection of tumor biomarkers is crucial for early diagnosis and prognosis evaluation of cancer. Owing to no need of labelled antibody, formation of sandwich immunocomplexes and additional solution-based probe, probe-integrated electrochemical immunosensor for reagentless detection of tumor biomarkers is highly desirable. In this work, sensitive and reagentless detection of a tumor biomarker is realized based on fabrication of a probe-integrated immunosensor by confining redox probe in electrostatic nanocage array modified electrode. Indium tin oxide (ITO) electrode is employed as the supporting electrode because it is cheap and easily available. The silica nanochannel array consisted of two layers with opposite charges or different pore diameters was designated as bipolar films (bp-SNA). In this work, Electrostatic nanocage array is equipped on ITO electrode by growth of bp-SNA with two layered nanochannel array having different charge properties including a negatively charged silica nanochannel array (n-SNA) and a positively charged amino-modified SNA (p-SNA). Each SNA can be easily grown with 15 s using electrochemical assisted self-assembly method (EASA). Methylene blue (MB) is applied as the model electrochemical probe with positive charge to be confined in electrostatic nanocage array with stirring. The combination of the electrostatic attraction from n-SNA and the electrostatic repulsion from p-SNA endows MB with highly stable electrochemical signal during continuous scanning. When the amino groups of p-SNA are modified using the bifunctional glutaraldehyde (GA) to introduce aldehydes, the recognitive antibody (Ab) of the most commonly used tumor biomarker, carcinoembryonic antigen (CEA), can be covalently immobilized. After the non-specific sites are blocked, the immunosensor is successfully fabricated. As the formation of antigen-antibody complex decreases electrochemical signal, the immunosensor can achieve reagentless detection of CEA ranged from 10 pg/mL to 100 ng/mL with a low limit of detection (LOD, 4 pg/mL). Determination of CEA in human serum samples is realized with high accuracy.

Oncolytic virus: A catalyst for the treatment of gastric cancer

Gastric cancer (GC) is a leading contributor to global cancer incidence and mortality. According to the GLOBOCAN 2020 estimates of incidence and mortality for 36 cancers in 185 countries produced by the International Agency for Research on Cancer (IARC), GC ranks fifth and fourth, respectively, and seriously threatens the survival and health of people all over the world. Therefore, how to effectively treat GC has become an urgent problem for medical personnel and scientific workers at this stage. Due to the unobvious early symptoms and the influence of some adverse factors such as tumor heterogeneity and low immunogenicity, patients with advanced gastric cancer (AGC) cannot benefit significantly from treatments such as radical surgical resection, radiotherapy, chemotherapy, and targeted therapy. As an emerging cancer immunotherapy, oncolytic virotherapies (OVTs) can not only selectively lyse cancer cells, but also induce a systemic antitumor immune response. This unique ability to turn unresponsive 'cold' tumors into responsive 'hot' tumors gives them great potential in GC therapy. This review integrates most experimental studies and clinical trials of various oncolytic viruses (OVs) in the diagnosis and treatment of GC. It also exhaustively introduces the concrete mechanism of invading GC cells and the viral genome composition of adenovirus and herpes simplex virus type 1 (HSV-1). At the end of the article, some prospects are put forward to determine the developmental directions of OVTs for GC in the future.

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.

Natural killer cell-targeted immunotherapy for cancer

Natural killer (NK) cells were initially described in the early 1970s as major histocompatibility complex unrestricted killers due to their ability to spontaneously kill certain tumor cells. In the past decade, the field of NK cell-based treatment has been accelerating exponentially, holding a dominant position in cancer immunotherapy innovation. Generally, research on NK cell-mediated antitumor therapies can be categorized into three areas: choosing the optimal source of allogenic NK cells to yield massively amplified "off-the-shelf" products, improving NK cell cytotoxicity and longevity, and engineering NK cells with the ability of tumor-specific recognition. In this review, we focused on NK cell manufacturing techniques, some auxiliary methods to enhance the therapeutic efficacy of NK cells, chimeric antigen receptor NK cells, and monoclonal antibodies targeting inhibitory receptors, which can significantly augment the antitumor activity of NK cells. Notably, emerging evidence suggests that NK cells are a promising constituent of multipronged therapeutic strategies, strengthening immune responses to cancer.

A nanobody targeting carcinoembryonic antigen as a promising molecular probe for non-small cell lung cancer

Carcinoembryonic antigen (CEA) is a biomarker and therapy target for non-small cell lung cancer (NSCLC), which is the most common type of lung cancer. Nanobodies with high target specificity are promising candidates to function as anti-CEA probes. In the present study, the targeting effects of an anti-CEA nanobody obtained from phage display were investigated using technetium-99 m (^99mTc) and fluorescence labeling. In vitro binding and immunofluorescent staining assays, as well as in vivo blood clearance and biodistribution assays were performed. High specificity and affinity of the nanobody for CEA-positive H460 cells was observed in vitro. The pharmacokinetics assay of the ^99mTc-nanobody in Wistar rats demonstrated that the nanobody had appropriate T_1/2α and T_1/2β, which were 20.2 and 143.5 min, respectively. The biodistribution assay using H460 xenograft-bearing nude mice demonstrated a high ratio of signal in tumor compared with background, which confirmed that the nanobody may be useful as a molecular probe for CEA-positive cancer, particularly in NSCLC.

Therapeutic anti-NLGP monoclonal antibody for carcinoembryonic antigen expressing tumors is nontoxic to Swiss and BALB/c mice

A murine monoclonal antibody (mAb), 1C8 was developed against a novel glycoprotein NLGP and its unique property to recognize carcinoembryonic antigen (CEA) was reported. Utilizing this CEA recognizing property, 1C8 is successful to restrict the growth of CEA(+) murine and human cancers both in vitro and in vivo. Here, we have thoroughly evaluated the toxicity profile of this mAb 1C8 on different physiological systems of both tumor-free and tumor-bearing Swiss and BALB/c mice. Effective concentration (25 μg/mice) of 1C8 caused no behavioral changes in animals and no death was recorded. Moreover, little increase in the body and organ weights in all mice groups was noted. MAb 1C8 showed no adverse effect on the hematological system, but little hematostimulation was noticed, as evidenced by increased hemoglobin content, leukocyte count and lymphocyte numbers. Liver enzymes like alkaline phosphatase, SGOT, SGPT and nephrological products like urea and creatinine assessment confirmed no abnormalities in both hepatic and renal functions. Number of T cells, B cells, NK cells, macrophages and dendritic cells was upregulated in vivo by mAb treatment with significant downregulation of regulatory T cells. During this treatment serum levels of type 1 cytokines were upregulated over type 2 cytokines. This mAb 1C8 also did not induce any significant increase in antibody titer following treatment. Accumulated evidences from Swiss and BALB/c mice strongly suggest that this mAb 1C8 is completely safe, thus, can be recommended for further clinical trial for the therapy of CEA(+) tumors.

Exogenous natural glycoprotein multiple mechanisms of anti-tumor activity

Natural glycoproteins can induce apoptosis of tumor cells and exert anti-tumor activity by immunomodulatory functions, cytotoxic and anti-inflammation effects, and inhibition of endothelial growth factor. Given their prospects as novel agents, sources of natural antitumor glycoproteins have attracted attention and new research directions in glycoprotein biology are gradually shifting to the direction of cancer treatment and prevention of neoplastic disease. In this review, we summarize the latest findings with regard to the tumor suppressor signature of glycoproteins and underlying regulatory mechanisms.