Levels Of GD3 Research Articles

GD2 and GD3 gangliosides as prognostic biomarkers in high grade serous ovarian cancer

ObjectiveGangliosides GD2 and GD3 have been proposed to be of significance in diagnosis of ovarian masses. We aim to study serum GD2 and GD3 gangliosides as predictors of oncological outcomes among high grade serous (HGS) ovarian cancer (OC). Materials and methodsA retrospective study including biobanked serum samples of HGS OC treated between 2005 and 2016. Serum GD2 and GD3 concentrations were quantified using indirect ELISA and analyzed with respect to survival. ResultsSixty patients were included. Patients with GD3>12.8 ng/mL had shorter PFS when compared to patients with lower level; median 31 vs. 67 months, p = 0.005. Patients with GD2> 7.1 ng/mL had shorter median PFS than those with lower level of (23 vs. 52 months, p = 0.024.) Patients with GD3>14.5 ng/mL had shorter OS vs. patients with lower level (median 31 vs. 70 months, p = 0.002). In a Cox regression, following adjustment for age, CA-125, disease stage and age, serum elevated GD3 was independently associated with short PFS (adjusted hazard ratio 2.0, 95 % CI 1.1–3.8, p=.024). In a separate Cox regression, elevated GD2 was independently associated with PFS (adjusted hazard ratio3.0 (1.2–7.7). p=.019. High serum GD3 and GD2 were independently associated with short OS as well. ConclusionsHigh levels of serum GD2 and GD3 in HGS OC were associated with shorter PFS and OS. GD3 is superior to GD2 as a biomarker for prognosis.

Single-cell profiling of surface glycosphingolipids opens a new dimension for deconvolution of breast cancer intratumoral heterogeneity and phenotypic plasticity

Glycosylated sphingolipids (GSLs) are a diverse group of cellular lipids typically reported as being rare in normal mammary tissue. In breast cancer (BCa), GSLs have emerged as noteworthy markers associated with breast cancer stem cells, mediators of phenotypic plasticity, and contributors to cancer cell chemoresistance. GSLs are potential surface markers that can uniquely characterize the heterogeneity of the tumor microenvironment, including cancer cell subpopulations and epithelial–mesenchymal plasticity (EMP). In this study, mass spectrometry analyses of the total sphingolipidome in breast epithelial cells and their mesenchymal counterparts revealed increased levels of Gb3 in epithelial cells and significantly elevated GD2 levels in the mesenchymal phenotype. To elucidate if GSL-related epitopes on BCa cell surfaces reflect EMP and cancer status, we developed and rigorously validated a 12-color spectral flow cytometry panel. This panel enables the simultaneous detection of native GSL epitopes (Gb3, SSEA1, SSEA3, SSEA4, and GD2), epithelial–mesenchymal transition markers (EpCAM, TROP2, and CD9), and lineage markers (CD45, CD31, and CD90) at the single-cell level. Next, the established panel was used for the analysis of BCa primary tumors and revealed surface heterogeneity in SSEA1, SSEA3, SSEA4, GD2, and Gb3, indicative of native epitope presence also on non-tumor cells. These findings further highlighted the phenotype-dependent alterations in GSL surface profiles, with differences between epithelial and stromal cells in the tumor. This study provides novel insights into BCa heterogeneity, shedding light on the potential of native GSL-related epitopes as markers for EMP and cancer status in fresh clinical samples. The developed single-cell approach offers promising avenues for further exploration.

Tb3+ doped silicoborate glass scintillator for high resolution synchrotron X-rays imaging application

This research aims to develop a combination of SiO2 and B2O3 glass former (called, silicoborate glass) to be used as a scintillation material for digital radiography application. The silicoborate glass doped with different concentration of Tb2O3, xTb2O3–7.5Gd2O3–40Na2O–5SiO2– (47.5-x)B2O3, where x = 0, 1, 2, and 3 mol% (xTb:7.5Gd) were prepared by melting and then rapid quenching in graphite mold. The density of the prepared glasses was high with Tb2O3 concentration, indicating that the glass became denser and could strongly interact with X-rays. The molar volume increased with Tb2O3 concentration, suggesting the increase of Non-Bridging Oxygen (NBOs) in glass matrix. The xTb:7.5Gd glasses absorbed photons in visible and near-infrared regions and was observed that the absorption bands increased with Tb2O3 concentration, which was the result of the 4f6-4f6 transitions behavior of Tb3+ ions. The photoluminescence and radioluminescence results revealed the distinct emission occurring at 544 nm (5D4→7F5). The photoluminescence quantum yield (PLQY) of glass had the maximum efficiency at 30.85%. The luminescence peak area under X-rays excitation glass was maximum at 109% of BGO crystal. CIE 1931 chromaticity of the xTb:7.5Gd glasses showed the color coordinates in yellowish-green area. The decay time of the xTb:7.5Gd glasses were in the millisecond range for different excitations. The probability of energy transfer was investigated between Gd3+ and Tb3+ ions in glass and may occur mainly between the 6P7/2 level of Gd3+ and 5H7 level of Tb3+. The X-rays imaging using the developed glass as a scintillator was performed by Synchrotron X-rays and the spatial resolution 6 lp/mm was achieved. These results demonstrate that the 3 mol% of Tb2O3 doped silicoborate glass can be used as a scintillator and can be applied for a high-resolution Synchrotron X-rays imaging system.

Structural Elucidation, IR spectroscopy and DC electrical conductivity of Ni0.6Zn0.4GdyFe2-yO4 nanoferrites synthesized via a low-temperature citrate gel combustion method

In the present work, we report the detailed Powder XRD Rietveld refinement and elucidation of structural factors of Ni0.6Zn0.4GdyFe2-yO4 nanoferrites. The Ni0.6Zn0.4GdyFe2-yO4 nanoferrites synthesized via low-temperature citrate gel combustion technique for the various levels of Gd3+ ion concentration (y = 0.0, 0.1, 0.15 and 0.20). The generated structural factors signify the dependence on the concentration of Gd3+ ions. The prepared samples were found to crystallize in the Fd-3m space group and also identified their occupancies; some of the Fe3+ ions of the octahedral site at the 16d position will be replaced by Gd3+ ions. The lattice constant and crystallite size dropped to a low value for y = 0.1, and then, later, noticed the small increment. The crystallite sizes of the sample are to fall in the range of 26.1 nm–37.6 nm. The cation distribution among the tetrahedral (AII) and octahedral sites (BII) has been estimated. The obtained values correlate with Gd3+ ion concentration, and the radius variation of AII and BII sites signifies the migration of Fe3+ ions from the BII site to the AII sites. The force constant of Metal-Oxygen bonds was determined from the infrared spectrographs; the force constant was found to be relatively low with the BII site. The DC electrical conductivity infers the semiconducting nature and distinct phase of conductivity, which is attributed to the magnetic phase change due to temperature. The magnetic curie temperatures of the sample are obtained by the Arrhenius plot, which signifies the dependence of Gd3+ion concentration.

Quercetin Induces Mitochondrial Apoptosis and Downregulates Ganglioside GD3 Expression in Melanoma Cells.

Malignant melanoma represents a form of skin cancer characterized by a bleak prognosis and heightened resistance to traditional therapies. Quercetin has demonstrated notable anti-carcinogenic, anti-inflammatory, anti-oxidant, and pharmacological effects across various cancer types. However, the intricate relationship between quercetin's anti-cancer properties and ganglioside expression in melanoma remains incompletely understood. In this study, quercetin manifests specific anti-proliferative, anti-migratory, and cell-cycle arrest effects, inducing mitochondrial dysfunction and apoptosis in two melanoma cancer cell lines. This positions quercetin as a promising candidate for treating malignant melanoma. Moreover, our investigation indicates that quercetin significantly reduces the expression levels of ganglioside GD3 and its synthetic enzyme. Notably, this reduction is achieved through the inhibition of the FAK/paxillin/Akt signaling pathway, which plays a crucial role in cancer development. Taken together, our findings suggest that quercetin may be a potent anti-cancer drug candidate for the treatment of malignant melanoma.

Abstract PO2-24-08: GD3 Synthase is a Master Regulator of Wild-Type p53–Mediated Apoptosis and Mutant p53–Mediated Tumorigenesis

Abstract The tumor suppressor protein p53 is essential for maintaining genomic stability and regulating cellular responses to stress. TP53 mutations are common in breast cancer (BC) and other malignancies. We previously showed that ganglioside GD2 identifies BC stem-like cells (BCSCs) and that GD3 synthase (GD3S/ST8SIA1) is upregulated in breast tumors with TP53 mutations. Here, we demonstrate the direct involvement of p53 in the transcriptional regulation of GD3S in the GD2 biosynthesis pathway. Our results uncover a novel role of GD3S in inhibiting p53-mediated apoptosis and promoting mutant p53–induced tumor initiation. To investigate the p53-mediated regulation of GD3S expression, we used the TCGA and METABRIC datasets and examined GD3S mRNA expression in breast tumors with different p53 mutation status. GD3S expression was significantly upregulated in BC patients with hotspot (HS) p53 mutations compared to those with wild-type (WT) p53 or non-HS p53 mutations (P< 0.0001). Immuno-histochemical analysis of GD3S and p53 in FFPE primary tumor tissues from BC patients (n=84) with varying p53 expression status demonstrated that patients with HS p53 mutations had higher histological scores for GD3S than did patients with WT p53 (P< 0.0001) or non-HS p53 mutations (P=0.009). GD3S and p53 expression were significantly positively correlated in patients with HS p53 mutations (r=0.735; P=0.006) but not in patients with WT p53 (r=–0.09) or non-HS p53 mutations (r=0.14). Consistent with these patient data, BC cells harboring HS p53 mutations had significantly upregulated and positively correlated expressions of GD3S and p53 (n=8; r=0.85). Moreover, compared to those with WT p53, the cells with HS p53 mutations had substantially greater populations of GD2+ BCSCs (P=0.02) and GD3+ BCSCs (P=0.01). Subsequently, we investigated the regulatory role of p53 in the GD2 biosynthetic pathway by stabilizing WT p53 expression by nutlin-3a treatment in 4 BC cell lines and suppressing the expression of HS p53 mutants by p53 knockdown in their respective cell lines (n=4). In cell lines with WT p53, nutlin-3a significantly decreased GD3S expression and GD2 levels (P< 0.05 and P< 0.0001, respectively), suggesting that WT p53 inhibits GD3S expression. In cell lines with p53 mutations, p53 knockdown significantly inhibited GD3S expression. In both cells with WT p53 (MCF7 and ZR751) and cells with HS p53 mutations (Hs578T and BT549), the stable overexpression of GD3S effectively suppressed apoptosis even when WT p53 was stabilized or HS p53 mutant expression was depleted. Consistent with these results, in mice bearing MCF7 cell–derived xenografts, the overexpression of GD3S counteracted the effect of stabilized WT p53–mediated apoptosis and facilitated tumor growth (P< 0.0001). The results of a promoter-luciferase reporter assay demonstrated that nutlin-3a reduced GD3S promoter activity in a dose-dependent manner in MCF7 and ZR751 cells (P< 0.0001), whereas doxycycline (1µM) significantly reduced GD3S promoter activity in Hs578T and BT549 cells with inducible p53 knockdown (P< 0.001). ChIP-qPCR analysis confirmed specific enrichment of WT p53 at the 300-bp upstream regions and additional enrichment of HS p53 mutants at the downstream regions of the GD3S promoter, indicating that WT p53 and HS p53 mutations have distinct promoter regulation patterns. In summary, our study reveals that GD3S has a previously unknown anti-apoptotic function in BC, in that it helps attenuate p53-mediated apoptosis while activating tumor-promoting pathways that operate independently of p53. Citation Format: Vivek Anand, FOUAD EL-DANA, JENNY BORGMAN, MICHAEL ANDREEFF, Venkata Lokesh Battula. GD3 Synthase is a Master Regulator of Wild-Type p53–Mediated Apoptosis and Mutant p53–Mediated Tumorigenesis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-24-08.

Transition to a mesenchymal state in neuroblastoma may be characterized by a high expression of GD2 and by the acquisition of immune escape from NK cells.

Neuroblastoma (NB) is characterized by both adrenergic (ADRN) and undifferentiated mesenchymal (MES) subsets. The ganglioside sialic acid-containing glycosphingolipid (GD2) is widely overexpressed on tumors of neuroectodermal origin promoting malignant phenotypes. MES cells are greatly enriched in post-therapy and relapsing tumors and are characterized by decreased expression of GD2. This event may cause failure of GD2-based immunotherapy. NK cells represent a key innate cell subset able to efficiently kill tumors. However, the tumor microenvironment (TME) that includes tumor cells and tumor-associated (TA) cells could inhibit their effector function. We studied eight NB primary cultures that, in comparison with commercial cell lines, more faithfully reflect the tumor cell characteristics. We studied four primary NB-MES cell cultures and two pairs of MES/ADRN (691 and 717) primary cultures, derived from the same patient. In particular, in the six human NB primary cultures, we assessed their phenotype, the expression of GD2, and the enzymes that control its expression, as well as their interactions with NK cells, using flow cytometry, RT-qPCR, and cytotoxicity assays. We identified mature (CD105+/CD133-) and undifferentiated (CD133+/CD105-) NB subsets that express high levels of the MES transcripts WWTR1 and SIX4. In addition, undifferentiated MES cells display a strong resistance to NK-mediated killing. On the contrary, mature NB-MES cells display an intermediate resistance to NK-mediated killing and exhibit some immunomodulatory capacities on NK cells but do not inhibit their cytolytic activity. Notably, independent from their undifferentiated or mature phenotype, NB-MES cells express GD2 that can be further upregulated in undifferentiated NB-MES cells upon co-culture with NK cells, leading to the generation of mature mesenchymal GD2bright neuroblasts. Concerning 691 and 717, they show high levels of GD2 and resistance to NK cell-mediated killing that can be overcome by the administration of dinutuximab beta, the anti-GD2 monoclonal antibody applied in the clinic. NB is a heterogeneous tumor representing a further hurdle in NB immunotherapy. However, different from what was reported with NB commercial cells and independent of their MES/ADRN phenotype, the expression of GD2 and its displayed sensitivity to anti-GD2 mAb ADCC indicated the possible effectiveness of anti-GD2 immunotherapy.

Investigation of Ca2Al2SiO7: Pr3+/Gd3+ UVB upconverting phosphor and its optical thermometric properties

On basis of fluorescence intensity ratio (FIR) over certain narrow coupled levels of rare-earth ions, up-conversion of RE-doped materials perform excellent temperature-sensing abilities for thermometry applications. A series of Pr3+/Gd3+ co-doped Ca2Al2SiO7 phosphors (Ca2Al2SiO7:Pr3+/Gd3+) were prepared by a conventional high-temperature solid-state reaction. Under excitation of blue ∼445 nm, the Ca2Al2SiO7:Pr3+/Gd3+ phosphor yields intense photoluminescence (PL) bands around 489, 528, 537, 580, 604, 613, and 646 nm due to electronic transition of 3P0 → 3H4, 3P0 → 3H5, 3P1 → 3H5, 3P1 → 3H6, 1D2 → 3H4, 3P0 → 3H6, and 3P0 → 3F2 of Pr3+, respectively. Their relative intensities are sensitively determined by Pr3+ contents, which, from 0.1 % to 5 %, tune the emission color from pink to warm white under excitation of 445 nm. It is of great interest that intense irradiation using a blue ∼445 laser does make efficient ultraviolet B (UVB) up-conversion at about 297, 306, and 313 nm, just stemming from the 6P3/2 → 8S7/2, 6P5/2 → 8S7/2, and 6P7/2 → 8S7/2 of Gd3+, respectively. A typical two-photon absorption process was proved to account for the UVB up-conversion, i.e. successive absorption of two blue ∼445 nm photons populating Pr3+ 4f5d excited state, which further efficiently transfer its energy to the 6IJ/6PJ states of Gd3+ neighbor for UVB emission. Moreover, the thermally coupled levels (TCLs) of Gd3+: 6P3/2-6P7/2, and Gd3+: 6P5/2-6P7/2 were thoroughly investigated for temperature sensing in 298–598 K. Maximum relative sensitivity of the 6P3/2-6P7/2 TCLs, i.e. Sr(I306/I313), is proved to be 0.96 % K−1 at 298 K, and that of the 6P5/2-6P7/2 TCLs, i.e. Sr(I297/I313), is 1 % K−1 at 373 K. The relevant thermal stabilities of the Ca2Al2SiO7:Pr3+/Gd3+ thermometric candidate was well validated with 10 cycles of heating and cooling processes in 298–598 K. Such continuous explorations of Pr3+/Gd3+ co-doping system will significantly promote the development of robust UVB up-converting phosphors as well as their practical applications in the field of high-resolution optical thermometry.

GD2-Targeting CAR T-cell Therapy for Patients with GD2+ Medulloblastoma.

Medulloblastoma (MB), the most common childhood malignant brain tumor, has a poor prognosis in about 30% of patients. The current standard of care, which includes surgery, radiation, and chemotherapy, is often responsible for cognitive, neurologic, and endocrine side effects. We investigated whether chimeric antigen receptor (CAR) T cells directed toward the disialoganglioside GD2 can represent a potentially more effective treatment with reduced long-term side effects. GD2 expression was evaluated on primary tumor biopsies of MB children by flow cytometry. GD2 expression in MB cells was also evaluated in response to an EZH2 inhibitor (tazemetostat). In in vitro and in vivo models, GD2+ MB cells were targeted by a CAR-GD2.CD28.4-1BBζ (CAR.GD2)-T construct, including the suicide gene inducible caspase-9. GD2 was expressed in 82.68% of MB tumors. The SHH and G3-G4 subtypes expressed the highest levels of GD2, whereas the WNT subtype expressed the lowest. In in vitro coculture assays, CAR.GD2 T cells were able to kill GD2+ MB cells. Pretreatment with tazemetostat upregulated GD2 expression, sensitizing GD2dimMB cells to CAR.GD2 T cells cytotoxic activity. In orthotopic mouse models of MB, intravenously injected CAR.GD2 T cells significantly controlled tumor growth, prolonging the overall survival of treated mice. Moreover, the dimerizing drug AP1903 was able to cross the murine blood-brain barrier and to eliminate both blood-circulating and tumor-infiltrating CAR.GD2 T cells. Our experimental data indicate the potential efficacy of CAR.GD2 T-cell therapy. A phase I/II clinical trial is ongoing in our center (NCT05298995) to evaluate the safety and therapeutic efficacy of CAR.GD2 therapy in high-risk MB patients.

Changes in the kinetic characteristics of free charge carriers in a narrow-gap semiconductor Pb<sub>1 – <i>x</i></sub>Gd<sub><i>x</i></sub>Te under the influence of electron paramagnetic resonance processes of Gd<sup>3+</sup> ions

In crystals of the narrow-gap semiconductor Pb1 – xGdxTe (x = 1.5 · 10–4) at temperatures T = 5–100 K, the method of electron paramagnetic resonance (EPR) revealed unusual dependences of the line shape of the EPR spectra of paramagnetic Gd3+ centers on temperature and the microwave power level in the spectrometer cavity. Based on the results of the analysis of the shape parameters of resonance lines recorded in the X-band, it was concluded that the most probable cause of changes in the observed EPR spectra is the effect of resonance transitions between the spin levels of Gd3+ centers on the kinetic characteristics of free charge carriers bound by exchange interactions with Gd3+ ions.

Biology of GD2 ganglioside: implications for cancer immunotherapy.

Part of the broader glycosphingolipid family, gangliosides are composed of a ceramide bound to a sialic acid-containing glycan chain, and locate at the plasma membrane. Gangliosides are produced through sequential steps of glycosylation and sialylation. This diversity of composition is reflected in differences in expression patterns and functions of the various gangliosides. Ganglioside GD2 designates different subspecies following a basic structure containing three carbohydrate residues and two sialic acids. GD2 expression, usually restrained to limited tissues, is frequently altered in various neuroectoderm-derived cancers. While GD2 is of evident interest, its glycolipid nature has rendered research challenging. Physiological GD2 expression has been linked to developmental processes. Passing this stage, varying levels of GD2, physiologically expressed mainly in the central nervous system, affect composition and formation of membrane microdomains involved in surface receptor signaling. Overexpressed in cancer, GD2 has been shown to enhance cell survival and invasion. Furthermore, binding of antibodies leads to immune-independent cell death mechanisms. In addition, GD2 contributes to T-cell dysfunction, and functions as an immune checkpoint. Given the cancer-associated functions, GD2 has been a source of interest for immunotherapy. As a potential biomarker, methods are being developed to quantify GD2 from patients' samples. In addition, various therapeutic strategies are tested. Based on initial success with antibodies, derivates such as bispecific antibodies and immunocytokines have been developed, engaging patient immune system. Cytotoxic effectors or payloads may be redirected based on anti-GD2 antibodies. Finally, vaccines can be used to mount an immune response in patients. We review here the pertinent biological information on GD2 which may be of use for optimizing current immunotherapeutic strategies.

GD2 and GD3 gangliosides as diagnostic biomarkers for all stages and subtypes of ovarian cancer.

e17604 Background: Ovarian cancer (OC) is the deadliest gynecological cancer, often diagnosed at advanced stages. A fast and accurate diagnostic method for early-stage OC is needed. The tumor marker gangliosides, GD2 and GD3, exhibit properties that make them ideal potential diagnostic biomarkers but they have never before been quantified in OC. We investigated the diagnostic utility GD2 and GD3 for diagnosis of all subtypes and stages of OC. Methods: This retrospective study evaluated GD2 and GD3 expression in biobanked tissue and serum samples from patients with invasive epithelial OC, healthy donors, non-malignant gynecological conditions, and other cancers. GD2 and GD3 levels were evaluated in tissue samples by immunohistochemistry (n=299), and in two cohorts of serum samples by quantitative ELISA. A Discovery Cohort (n=379) showed feasibility of GD2 and GD3 quantitative ELISA for diagnosing OC, and a subsequent Model Cohort (n=200) was used to train and cross-validate a diagnostic model. Results: GD2 and GD3 were expressed in tissues of all OC subtypes and FIGO stages but not in surrounding healthy tissue or other controls. In serum, GD2 and GD3 were elevated in patients with OC. A novel diagnostic model that included serum levels of GD2 and GD3 was superior to the standard of care (CA125, p<0.001) at detecting OC, as well as, in early-stage (I/II) OC samples. Conclusions: GD2 and GD3 are high value candidates for building a novel diagnostic panel. A diagnostic model combining GD2 and GD3 quantification in serum had diagnostic power for all subtypes and all stages of OC, including early-stage. Further research exploring the utility GD2 and GD3 for diagnosis of OC is warranted. Future work will aim to validate these biomarkers in independent prospective studies. [Table: see text]

GD2 and GD3 gangliosides as diagnostic biomarkers for all stages and subtypes of epithelial ovarian cancer.

Ovarian cancer (OC) is the deadliest gynecological cancer, often diagnosed at advanced stages. A fast and accurate diagnostic method for early-stage OC is needed. The tumor marker gangliosides, GD2 and GD3, exhibit properties that make them ideal potential diagnostic biomarkers, but they have never before been quantified in OC. We investigated the diagnostic utility of GD2 and GD3 for diagnosis of all subtypes and stages of OC. This retrospective study evaluated GD2 and GD3 expression in biobanked tissue and serum samples from patients with invasive epithelial OC, healthy donors, non-malignant gynecological conditions, and other cancers. GD2 and GD3 levels were evaluated in tissue samples by immunohistochemistry (n=299) and in two cohorts of serum samples by quantitative ELISA. A discovery cohort (n=379) showed feasibility of GD2 and GD3 quantitative ELISA for diagnosing OC, and a subsequent model cohort (n=200) was used to train and cross-validate a diagnostic model. GD2 and GD3 were expressed in tissues of all OC subtypes and FIGO stages but not in surrounding healthy tissue or other controls. In serum, GD2 and GD3 were elevated in patients with OC. A diagnostic model that included serum levels of GD2+GD3+age was superior to the standard of care (CA125, p<0.001) in diagnosing OC and early-stage (I/II) OC. GD2 and GD3 expression was associated with high rates of selectivity and specificity for OC. A diagnostic model combining GD2 and GD3 quantification in serum had diagnostic power for all subtypes and all stages of OC, including early stage. Further research exploring the utility of GD2 and GD3 for diagnosis of OC is warranted.

7,8-Dihydroxyflavone induces mitochondrial apoptosis and down-regulates the expression of ganglioside GD3 in malignant melanoma cells

Malignant melanoma is a skin cancer with poor prognosis and high resistance to conventional treatment. 7,8-dihydroxyflavone (7,8-DHF) has shown anti-carcinogenic, anti-inflammatory, anti-oxidant, and pharmacological effects in several types of cancer. However, the relationship between ganglioside expression and the anti-cancer effects of 7,8-DHF in melanoma is not fully understood. In the present study, 7,8-DHF exhibits specific anti-proliferation, anti-migration, and G2/M phase cell-cycle arrest effects on both melanoma cancer cell lines, and induces mitochondrial dysfunction and apoptosis, making it a potent candidate for anti-melanoma treatment. Furthermore, we confirmed that 7,8-DHF significantly reduces the expression levels of ganglioside GD3 and its synthase, which are known to be closely involved in carcinogenesis. Taken together, our findings suggest that 7,8-DHF may be a potent anti-cancer drug candidate for the treatment of malignant melanoma.

T CELLS ENGINEERED TO EXPRESS A CAR ANTI-GD2 AND THE COSTIMULATORY MOLECULE GITRL ERADICATE GLIOBLASTOMA CELLS AND ARE IFNY PRODUCERS

The adoptive transfer of T lymphocytes expressing chimeric antigen receptors (CAR) has resulted in impressive complete remission rates in B-cell malignancies. However, the therapeutic efficacy of CAR-T cells is still low or non-existent against solid tumors, which make up the vast majority of neoplasms. One of the main reasons for this failure is the presence of ligands and immunosuppressive cells in the tumor microenvironment. The complete activation of T cells requires the engagement of costimulatory molecules whose expression is temporally segregated and whose nature of biochemical signals are complementary. This is the case of CD28, expressed constitutively, and GITR, expressed right after the initial activation of T cells. Therefore, our hypothesis is that the combined expression of a CAR containing the costimulatory domain CD28 and the GITR ligand (GITRL) will potentiate the antineoplastic action of CAR-T cells. In addition to providing complementary costimulatory signals for effector CAR-T cells, GITRL can suppress the action of regulatory T cells in the tumor microenvironment, thus possibly reducing local immunosuppression. Then, the aim of this study is to evaluate the therapeutic efficiency of anti-GD2 CAR-T cells coexpressing GITRL in a preclinical model of glioblastoma multiforme. In this project, we used as a model a CAR against the ganglioside GD2, which is highly immunogenic and expressed in tumors of neuroectodermal origin, such as glioblastoma. To test our hypothesis, we generated two lentiviral vectors to express CAR anti-GD2 and another one coexpressing GITRL as a costimulatory domain. After that, we produced lentiviral particles to transduced human T lymphocytes and we detected CAR expression in the T cells transduced with both vectors. To verify the functional activity of these CAR-T cells, we performed a coculture assay against T98G cell line, which express high levels of GD2, and HCT-166 cell, that dont express. These cell lines were previously modified to express luciferase to enable the analysis through bioluminescence imaging. We tested two ratios of effector:target cells (E:T) and we observed that both CAR.GD2 and CAR.GD2-GITRL T cells demonstrated powerful capacity of lysis only against cells that express GD2. Then, we interrogated whether these CAR-T cells could keep their lysis capacity after additional rechallenges. So, another two rounds of coculture were performed and the cells showed persistence of cytotoxicity. In addition, tumor cell killing was associated with secretion of IFNy as evaluated by ELISA quantification of coculture supernatants. These data encouraged us to compare the antineoplastic activity and persistence of CAR-T cells anti-GD2 in an orthotopic pre-clinical model of glioblastoma multiforme, which is under way. We expect that the potential results of this project will foster the development of a new advanced cellular immunotherapy strategy for the treatment of solid GD2+ neoplasms and will pave the way to increase the antineoplastic efficiency of CAR-T cells against other malignancies.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Enhancement of near-infrared emission through Gd3+ mediated energy transfer in fluoride nanoparticles under X-ray excitation

High energy X-rays have been widely employed in biological and medical fields because of its unlimited penetration depth in biological tissues and near-infrared (NIR) emission is considered as a preferred signal in bioimaging and biosensing. However, it remains a big challenge for nanoparticles to emit high intensity NIR light upon X-ray radiation due to the presence of defects and material's intrinsic low X-ray absorption ability. In this work, we prepare NaLuF4: Gd, Tm nanoparticles with different doping levels of Gd3+ and Tm3+ ions and systematically study the NIR emission properties under X-ray irradiation. NaLuF4: 20Gd, 1 Tm nanoparticles exhibits ∼3.5 times stronger radioluminescence at 800 nm as compared to solely Tm3+ doped nanoparticles. When X-ray induced electrons and holes recombine, Gd3+ ions serve as energy absorber and transfer the optical energy to Tm3+ ions. Excessive amount of Gd3+ ions will result in efficient energy flow to defects and apparent decreased NIR emission which can be confirmed by the lifetime curves of 3H4 states of Tm3+ ion. We further examine the X-ray-induced afterglow intensity of nanoparticles at 800 nm and demonstrate conceptually bioimaging with a deep penetration depth using the developed nanoparticles. The clear picture taken by a NIR camera indicates the NaLuF4: 20Gd, 1 Tm nanoparticles can be used a promising probe for X-ray luminescence optical imaging.

Therapeutic efficacy of antibody-drug conjugates targeting GD2-positive tumors

BackgroundBoth ganglioside GD2-targeted immunotherapy and antibody-drug conjugates (ADCs) have demonstrated clinical success as solid tumor therapies in recent years, yet no research has been carried out to develop anti-GD2 ADCs...

Beyond the Energy Gap Law: The Influence of Selection Rules and Host Compound Effects on Nonradiative Transition Rates in Boltzmann Thermometers

AbstractApart from the energy gap law, control parameters over nonradiative transitions are so far only scarcely regarded. In this work, the impact of both covalence of the lanthanoid–ligand bond and varying bond distance on the magnitude of the intrinsic nonradiative decay rate between the excited 6P5/2 and 6P7/2 spin–orbit levels of Gd3+ is investigated in the chemically related compounds Y2[B2(SO4)6] and LaBO3. Analysis of the temperature‐dependent luminescence spectra reveals that the intrinsic nonradiative transition rates between the excited 6PJ ( J = 5/2, 7/2) levels are of the order of only 10 ms−1 (Y2[B2(SO4)6]:Gd3+: 8.9 ms−1; LaBO3:Gd3+: 10.5 ms−1) and differ due to the different degree of covalence of the GdO bonds in the two compounds. Comparison to the established luminescent Boltzmann thermometer Er3+ reveals, however, that the nonradiative transition rates between the excited levels of Gd3+ are over three orders of magnitude slower despite a similar energy gap and the presence of a single resonant phonon mode. This hints to a fundamental magnetic dipolar character of the nonradiative coupling in Gd3+. These findings can pave a way to control nonradiative transition rates and how to tune the dynamic range of luminescent Boltzmann thermometers.

Role of GD3 Synthase ST8Sia I in Cancers.

Simple SummaryThe carbohydrate moiety of cell surface glycolipids is modified in cancers of neuro–ectoderm origin, leading to the expression of more complex structures with two or more sialic acid residues. These alterations result from the upregulation of the ST8SIA1 gene that encodes GD3 synthase, the enzyme controlling the biosynthesis of complex gangliosides, and are usually associated with a more aggressive phenotype and a poor outcome for patients, making GD3 synthase an interesting target for cancer therapy. This review reports our general knowledge of GD3 synthase gene expression and regulation, its role in both epithelial–mesenchymal transition (EMT) and cancer progression, and the different approaches targeting GD3S expression in cancers.GD3 synthase controls the biosynthesis of complex gangliosides, bearing two or more sialic acid residues. Disialylated gangliosides GD3 and GD2 are tumor-associated carbohydrate antigens (TACA) in neuro–ectoderm-derived cancers, and are directly involved in cell malignant properties, i.e., migration, invasion, stemness, and epithelial–mesenchymal transition. Since GD3 and GD2 levels are directly linked to GD3 synthase expression and activity, targeting GD3 synthase appears to be a promising strategy through which to interfere with ganglioside-associated malignant properties. We review here the current knowledge on GD3 synthase expression and regulation in cancers, and the consequences of complex ganglioside expression on cancer cell signaling and properties, highlighting the relationships between GD3 synthase expression and epithelial–mesenchymal transition and stemness. Different strategies were used to modulate GD3 synthase expression in cancer cells in vitro and in animal models, such as inhibitors or siRNA/lncRNA, which efficiently reduced cancer cell malignant properties and the proportion of GD2 positive cancer stem cells, which are associated with high metastatic properties, resistance to therapy, and cancer relapse. These data show the relevance of targeting GD3 synthase in association with conventional therapies, to decrease the number of cancer stem cells in tumors.