The inactivation of p53, a tumor suppressor, and the activation of the RAS oncogene are the most frequent genetic alterations in cancer. We have shown that a unique E. coli MazF-MazE toxin-antitoxin ...(TA) system can be used for selective and effective eradication of RAS-mutated cancer cells. This out of the box strategy holds great promise for effective cancer treatment and management. We provide proof of concept for a novel platform to selectively eradicate cancer cells using an adenoviral delivery system based on the adjusted natural bacterial system. We generated adenoviral vectors carrying the mazF toxin (pAdEasy-Py4-SV40mP-mCherry-MazF) and the antitoxin mazE (pAdEasy-RGC-SV40mP-MazE-IRES-GFP) under the regulation of RAS and p53, resp. The control vector carries the toxin without the RAS-responsive element (pAdEasy-ΔPy4-SV40mP-mCherry-MazF). In vitro, the mazF-mazE TA system (Py4-SV40mP-mCherry-MazF+RGC-SV40mP-MazE-IRES-GFP) induced massive, dose-dependent cell death, at 69% compared to 19% for the control vector, in a co-infected HCT116 cell line. In vivo, the system caused significant tumor growth inhibition of HCT116 (KRAS
/p53
) tumors at 73 and 65% compared to PBS and ΔPY4 control groups, resp. In addition, we demonstrate 65% tumor growth inhibition in HCT116 (KRAS
/p53
) cells, compared to the other two control groups, indicating a contribution of the antitoxin in blocking system leakage in WT RAS cells. These data provide evidence of the feasibility of using mutations in the p53 and RAS pathway to efficiently kill cancer cells. The platform, through its combination of the antitoxin (mazE) with the toxin (mazF), provides effective protection of normal cells from basal low activity or leakage of mazF.
A small but significant proportion of COVID‐19 patients develop life‐threatening cytokine storm. We have developed a new anti‐inflammatory drug, EXO‐CD24, a combination of an immune checkpoint (CD24) ...and a delivery platform (exosomes). CD24 inhibits the NF‐kB pathway and the production of cytokines/chemokines. EXO‐CD24 discriminates damage‐from pathogen‐associated molecular patterns (DAMPs and PAMPs) therefore does not interfere with viral clearance. EXO‐CD24 was produced and purified from CD24‐expressing 293‐TREx™ cells. Exosomes displaying murine CD24 (mCD24) were also created. EXO‐CD24/mCD24 were characterized and examined, for safety and efficacy, in vitro and in vivo. In a phase Ib/IIa study, 35 patients with moderate–high severity COVID‐19 were recruited and given escalating doses, 108–1010, of EXO‐CD24 by inhalation, QD, for 5 days. No adverse events related to the drug were observed up to 443–575 days. EXO‐CD24 effectively reduced inflammatory markers and cytokine/chemokine, although randomized studies are required. EXO‐CD24 may be a treatment strategy to suppress the hyper‐inflammatory response in the lungs of COVID‐19 patients and further serve as a therapeutic platform for other pulmonary and systemic diseases characterized by cytokine storm.
Synopsis
In 5% of COVID‐19 patients, 5–10 days from disease onset, there is rapid clinical deterioration due to the cytokine storm with no effective therapy. EXO‐CD24 is the new immunomodulator with promising efficacy without interfering with pathogen clearance.
EXO‐CD24 is a novel platform that helps normalize immune activity.
EXO‐CD24 may represent a new therapeutic opportunity to overcome the devastating effect of COVID‐19 and beyond.
EXO‐CD24 leads to inhibition of tissue injury‐driven inflammation without interfering with pathogen‐induced immune activation.
EXO‐CD24 is a targeted innovative technology, based on CD24‐enriched exosomes, delivered directly to the lungs to suppress the cytokine storm, and has broad applicability.
In 5% of COVID‐19 patients, 5–10 days from disease onset, there is rapid clinical deterioration due to the cytokine storm with no effective therapy. EXO‐CD24 is the new immunomodulator with promising efficacy without interfering with pathogen clearance.
The integration of viral DNA into the host genome is mediated by viral integrase, resulting in the accumulation of double-strand breaks. Integrase-derived peptides (INS and INR) increase the number ...of integration events, leading to escalated genomic instability that induces apoptosis. CD24 is a surface protein expressed mostly in cancer cells and is very rarely found in normal cells. Here, we propose a novel targeted cancer therapeutic platform based on the lentiviral integrase, stimulated by integrase-derived peptides, that are specifically delivered to cancerous cells via CD24 antigen-antibody targeting. INS and INR were synthesized and humanized and anti-CD24 antibodies were fused to the lentivirus envelope. The activity, permeability, stability, solubility, and toxicity of these components were analyzed. Cell death was measured by fluorescent microscopy and enzymatic assays and potency were tested in vitro and in vivo. Lentivirus particles, containing non-functional DNA led to massive cell death (40-70%). Raltegravir, an antiretroviral drug, inhibited the induction of apoptosis. In vivo, single and repeated administrations of INS/INR were well tolerated without any adverse effects. Tumor development in nude mice was significantly inhibited (by 50%) as compared to the vehicle arm. In summary, a novel and generic therapeutic platform for selective cancer cell eradication with excellent efficacy and safety are presented.
Increased expression of CD24 is seen in a large variety of solid tumors, including up to 90% of gastrointestinal (GI) tumors. Stable derivatives of SW480 colorectal cancer (CRC) cells that ...overexpress CD24 proliferate faster, and increase cell motility, saturation density, plating efficiency, and growth in soft agar. They also produce larger tumors in nude mice as compared to the parental SW480 cells. Most significantly, even depletion of one copy of the CD24 allele in the APCMin/+ mice of a transgenic mouse model led to a dramatic reduction in tumor burden in all sections of the small intestine. Homozygous deletion of both CD24 alleles resulted in complete abolishment of tumor formation. Moreover, CD24 knockout mice exhibited resistance to chemically induced inflammation‐associated CRC. Finally, a new signal transduction pathway is suggested: namely, CD24 expression downstream to COX2 and PGE2 synthesis, which is directly regulated by β‐catenin. CD24 is shown in vitro and in vivo as being an important oncogene in the gut, and one that plays a critical role in the initiation and progression of carcinogenesis.
What's new?
While its pathophysiologic function largely remains unclear, CD24 has been suggested to play a role in the pre‐invasive and pre‐metastatic stages of human tumor cells. The present study shows in vitro and in vivo that CD24 is an important oncogene in the gut. CD24 depletion completely abolishes tumor burden in the ApcMin mice model, and its overexpression causes colorectal cancer cells to have a more aggressive phenotype. COX2‐PGE2‐β‐catenin‐CD24 is suggested as a novel pathway that may come into play early during the multistep process of gastrointestinal carcinogenesis. CD24 may serve for early detection, surveillance, and as a target for therapy.
Background:
Curcumin, green tea polyphenols and selenium possess anti-inflammatory and anti-oxidant properties. Individually they have demonstrated some efficacy in animal models and human subjects ...with inflammatory bowel disease (IBD). To evaluate the efficacy and safety of Coltect Curcumin (500 mg), green tea (250 mg) and selenium (100 µg) in vivo and in patients with ulcerative colitis (UC).
Methods:
Each component was compared to placebo in a DSS mice colitis model. The efficacy was validated in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) rat colitis model. Twenty patients with mild-to-moderate UC received two Coltect tablets twice daily for 8 weeks. Enrollees underwent sigmoidoscopy at study entrance and closure, and physical and laboratory evaluation at baseline, 4 and 8 weeks.
Results:
Coltect showed a synergistic therapeutic effect in the DSS and TNBS models. Disease activity was significantly higher in the placebo versus the treated group (p < 0.05). Selenium was the more active component. The contribution of green tea was minor. In the TNBS model, the Wallace scores for macroscopic lesions were 4.8 ± 1.5 (treatment) and 8.2 ± 0.5 (placebo) (p = 0.01). In humans, Coltect was well tolerated and effective. Fourteen subjects (70%) improved: nine (45%) went into complete remission, four (20%) experienced marked improvement and one (5%) experienced moderate improvement at the end of the trial. Clinical activity index decreased significantly at 4 and 8 weeks (p < 0.001). Two patients had no change in their symptoms, and one withdrew after 4 weeks. Flare-up in four subjects caused three to withdraw from the study after less than 4 weeks. Endoscopic improvement was observed in 11 (69%) patients, and four patients (25%) achieved complete remission.
Conclusions:
Coltect may serve as a first-line or add-on therapy in patients with mild-to-moderate UC.
Healthy individuals rarely have problems with wound healing. Most skin lesions heal rapidly and efficiently within one to two weeks. However, many medical and surgical complications can be attributed ...to deficiencies in wound repair. Open wounds have lost the barrier that protects tissues from bacterial invasion and allows the escape of vital fluids. Without expeditious healing, infections become more frequent. The CD24 gene encodes a heavily-glycosylated cell surface protein anchored to the membrane by phosphatidylinositol. CD24 plays an important role in the adaptive immune response and controls an important genetic checkpoint for homeostasis and autoimmune diseases in both mice and humans. We have previously shown that overexpression of CD24 results in increased proliferation and migration rates.
To examine the role of CD24 in the wound healing process.
An excisional model of wound healing was used and delayed wound healing was studied in genetically modified heat stable antigen (HSA/CD24)-deficient mice (HSA-/-) compared to wild-type (WT) mice.
Large full-thickness skin wounds, excised on the back of mice, exhibited a significant delay in the formation of granulation tissue, and in wound closure when compared to their WTHSA+/+ littermates. Wounds were histologically analyzed and scored, based on the degree of cellular invasion, granulation tissue formation, vascularity, and re-epithelialization. Additionally, in stitched wounds, the HSA-/- mice failed to maintain their stitches; they did not hold and fell already 24 hours, revealing erythematous wound fields. Re-expression of HSA, delivered by lentivirus, restored the normal healing phenotype, within 24 hours post-injury, and even improved the healing in WT, and in BalbC mice.
Delayed wound-healing in the absence of HSA/CD24 suggests that CD24 plays an important role in this process. Increased expression of CD24, even in the normal state, may be used to enhance wound repair.
The heat-stable HSA/CD24 gene encodes a protein that shows high expression levels in adipocyte precursor cells but low levels in terminally differentiated adipocytes. Its high expression in many ...types of human cancer suggests an association between cancer, diabetes, and obesity, which is currently unclear. In addition, peroxisome proliferator-activated receptor gamma (PPARγ) is a regulator of adipogenesis that plays a role in insulin sensitivity, lipid metabolism, and adipokine expression in adipocytes.
To assess gender-dependent changes in CD24 KO and its association with PPARγ expression.
WT and CD24 KO mice were monitored from birth up to 12 months, and various physiological and molecular characteristics were analysed. Mean body weight and adipose mass were higher in KO mice than in WT mice. Male, but not female, KO mice showed increased insulin sensitivity, glucose uptake, adipocyte size, and PPARγ expression than WT mice. In addition, enteric bacterial populations, assessed through high-throughput sequencing of stool 16S rRNA genes, were significantly different between male KO and WT mice.
CD24 may negatively regulate PPARγ expression in male mice. Furthermore, the association between the CD24 and insulin sensitivity suggests a possible mechanism for diabetes as a cancer risk factor. Finally, CD24 KO male mice may serve as a model of obesity and insulin hyper-sensitivity.
An estimated 1.24 million blood cancer cases occur annually worldwide, accounting for approximately 6% of all cancer cases. Currently, there are no standardized hematology cancer screening tests that ...are recommended for the general population. CD24 is a mucin-like cell surface molecule and P-selectin ligand, which plays a significant role in the maturation of B-lymphocytes and was found to be overexpressed in a number of hematological malignancies. Our primary aim was to assess the sensitivity and specificity of the CD24/CD11b-based blood test for the detection of hematological malignancies. Our cohort included 488 subjects with positive hematological cancer diagnosis (
= 122) and healthy subjects (
= 366). CD24/CD11b expression in peripheral blood leukocytes (PBLs) obtained from blood samples of participants was analyzed by flow cytometry. Our results demonstrated that the average levels of CD24/CD11b in healthy patients (21.7 ± 9.0) were statistically significantly lower compared to levels of CD24/CD11b in cancer patients (29.5 ± 18.7,
< 0.001). The highest levels of CD24/CD11b were found in multiple myeloma (39.1 ± 23.6), followed by chronic myeloid leukemia (33.0 ± 13.7) and non-Hodgkin lymphoma (32.3 ± 13.3). The test had an overall sensitivity for hematologic cancers of 78.5% (95% CI, 70.7-86.3%) and specificity of 80.2% (95% CI, 76.1-84.3%). In conclusion, our findings indicate the feasibility of a CD24/CD11b-based blood test as a screening test of hematological malignancies.
The CD24 gene has raised considerable interest in tumor biology as a new prognostic factor and a biomarker for the early detection of cancer. There are currently no studies that assess predictors of ...CD24 in blood tests among healthy individuals. Our aims were (1) to evaluate predictors of the CD24/CD11b biomarker among healthy subjects and (2) to assess CD24/CD11b levels of participants with and without benign tumors. Our cohort included 1640 healthy subjects, aged 20–85, recruited at the Health Promotion and Integrated Cancer Prevention Center (ICPC) in the Tel Aviv Medical Center. Eligible subjects completed a detailed questionnaire on medical history and other epidemiologic information. CD24/CD11b expression in peripheral blood leukocytes (PBLs) obtained from blood samples of participants was analyzed by flow cytometry. Our results showed that the average levels of CD24/CD11b in healthy patients (22.8 ± 9.3) was statistically significant lower compared to subjects with benign cancers (26.1 ± 10.5, p < 0.001). Our multivariable analysis demonstrated that elevated levels of CRP (coefficient β: 1.98, p = 0.011) were significantly associated with high levels of CD24/CD11b expression among healthy participants. Other risk factors of cancer were not associated with elevated CD24 levels among healthy subjects. In conclusion, our findings may assist in further development and optimization of the CD24/CD11b biomarker to serve as a cancer screening test for early detection of cancer among the healthy population.
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