High Antitumor Activity Research Articles

Abstract 3600: Reversal of iNKT cell dysfunction in cholangiocarcinoma

Abstract Invariant natural killer T (iNKT) cells are CD1d-restricted unconventional T cells possessing innate and adaptive immunity with high anti-tumor activities. Yet, the effectiveness of iNKT cell therapy in clinical trials is limited due to iNKT cell dysfunction after exposure to the tumor microenvironment. Aggressive cholangiocarcinoma (CCA) cell lines were used to study iNKT cell reactivity. These CCA cell lines lacked CD1d molecules and responded poorly to iNKT cells. The iNKT cells became dysfunctional after the exposure to CCA by 48 h. In this study, we overcame iNKT cell dysfunction by searching for a small molecule to prevent or reverse the gene sets regulating iNKT cell dysfunction, thus prolonging anti-tumor activity. It was found that P53 and estrogen early response pathway gene sets were enriched in dysfunctional iNKT cells which were reversed by vorinostat, an HDAC inhibitor. Anti-CCA activity of iNKT cells was regained with a subtherapeutic dose of vorinostat as protection. Interestingly, vorinostat could not totally recover the anti-tumor effect of iNKT cells that have already developed into the dysfunctional stage. Significant tumor size reduction was seen in the humanized mouse model after iNKT cell adoptive therapy was given in combination with vorinostat compared to monotherapy with either iNKT cell or vorinostat alone. This study demonstrated that inhibiting the gene sets regulating iNKT cell dysfunction by vorinostat could prevent iNKT cell dysfunction, and prolong its anti-tumor activities. This combination could be a novel treatment option for CD1d-negative CCA patients resistant to standard chemotherapy. Citation Format: Khin Su Su Htwe, Kitipong Soontrapa, Siwanon Jirawatnotai, Sunisa Prasopporn, Pimkanya More-Krong, Somponnat Sampattavanich, Adisak Wongkajornsilp. Reversal of iNKT cell dysfunction in cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3600.

Abstract 6324: Antagonism-enforced braking system to enhance CAR T cell therapeutic specificity

Abstract Chimeric Antigen Receptor (CAR) T cell immunotherapy represents a breakthrough in the treatment of hematological malignancies. However, the rarity of cell surface protein targets that are specific to cancerous but not vital healthy tissue has hindered its broad application to solid tumor treatment. While new logic-gated CAR designs have shown reduced toxicity against healthy tissues, the generalizability of such approaches across tumors remains unclear. Here, we harness a universal characteristic of endogenous T cell receptors (TCRs), their ability to discriminate between self and non-self ligands through inhibition of response against self (weak) antigens, to develop a broadly applicable method of enhancing immunotherapeutic precision. We hypothesized that this discriminatory mechanism, known as antagonism, would apply across receptors, allowing for a transfer of specificity from TCRs onto CARs. We therefore systematically mapped out the responses of CAR T cells to joint TCR and CAR stimulations. We first engineered murine T cells with an ovalbumin-specific TCR to express a CAR targeting murine CD19 and discovered that the expression of a strong TCR antigen on CD19+ leukemia enhanced CAR T killing. Importantly though, the presence of a weak TCR antigen antagonized CAR T responses, assessed by in vitro multiplexed dynamic profiling as well as in vivo cytotoxicity. We developed a mathematical model based on cross-receptor inhibitory coupling that accurately predicted the extent of TCR/CAR antagonism across a wide range of immunological settings. This model was validated in a CD19+ B16 mouse melanoma model showing that TCR/CAR antagonism decreased the infiltration of a tumor-reactive T cell cluster, while TCR/CAR agonism enhanced infiltration of this T cell cluster. We then applied our quantitative knowledge of TCR/CAR crosstalk to design an Antagonism-Enforced Braking System (AEBS) for CAR T cell therapy. This was assessed in a model system using a CAR targeting the tyrosine-protein kinase erbB-2 (HER2) together with a hedgehog acyltransferase (HHAT) peptide-specific TCR that binds strongly to mutated tumor neoantigen while retaining weak affinity for the wild-type self-antigen on healthy tissue. We established a humanized in vivo model of CAR T function and found that AEBS CAR T cells maintained high anti-tumor activity against a human lung adenocarcinoma (PC9) but notably, their anti-tissue cytotoxicity against human bronchial epithelial cells (BEAS-2B) was minimized. AEBS CAR T cells therefore sharpen the discriminatory power of synthetic anti-tumor lymphocytes. Our work highlights a novel mechanism by which TCRs can enforce CAR T cell specificity, with practical implications for the rational design of future anti-leukemia immunotherapies. Citation Format: Taisuke Kondo, François X. Bourassa, Sooraj Achar, Justyn DuSold, Pablo Cespedes, Madison Wahlsten, Audun Kvalvaag, Guillaume Gaud, Paul Love, Michael Dustin, Gregoire Altan-Bonnet, Paul François, Naomi Taylor. Antagonism-enforced braking system to enhance CAR T cell therapeutic specificity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6324.

Copper Nanodrugs by Atom Transfer Radical Polymerization

In this study, some copper catalysts used for atom transfer radical polymerization (ATRP) were explored as efficient anti‐tumor agents. The aqueous solution of copper‐containing nanoparticles with uniform spheric morphology was in situ prepared through a copper‐catalyzed activator generated by electron transfer (AGET) ATRP in water. Nanoparticles were then directly injected into tumor‐bearing mice for antitumor chemotherapy. The copper nanodrugs had prolonged blood circulation time and enhanced accumulation at tumor sites, thus showing potent antitumor activity. This work provides a novel strategy for precise and large‐scale preparation of copper nanodrugs with high antitumor activity.

Microbial exopolysaccharide composites with inorganic materials and their biomedical applications: A review

Microbial exopolysaccharides (EPS) are high molecular weight carbohydrate-based materials produced and secreted in response to external environmental stress to protect microbial cells. These molecules also contain non-carbohydrate moieties including acetate, pyruvate, phosphate, and succinate along with sugar molecules. EPS has been incorporated into industrial operations as a gelling, emulsifying, and stabilizing agent to increase viscosity. Besides, these molecules have also shown high biocompatibility, immunomodulatory, antitumor, anti-microbial, and anti-viral activity which suggest their possible applications in healthcare. However, these molecules are facing some commercial shortcomings due to low stability, bioactivity, and poor mechanical and tensile strength in comparison to the required standard. Hence use of composites of EPS with other polymers and moieties has been suggested for higher performance. Especially in the context of inorganic moieties like silver, gold nanomaterials, clay, salts, and minerals will add bioactivity and functional sites for the attachment of drug molecules and other compounds. The current review summarizes the higher physical and chemical characteristics of EPS composites with inorganic materials and their immense potential in the biomedical sector.

Novel thiosemicarbazone complexes as anticancer agents: Synthesis, characterization, cytotoxicity, docking, and density functional theory studies

New Co (II), Ni (II), and Cu (II) complexes based on ρ‐dimethylaminobenzaldehyde thiosemicarbazone (DABT) as chelating agents were synthesized. The structure of the three complexes was determined by elemental analysis and TGA with IR, UV–Vis, XRD, ESR spectra, conductivity, and magnetic measurements. It was found that the isolated DABT complexes have tetrahedral structure with a neutral nature. The antitumor activity of DABT complexes using viability assay was examined against hepatocellular carcinoma cell lines (HepG‐2). The DABT complexes have moderate activity with respect to the standard drugs. DABT–Ni (II) complex has higher antitumor activity (IC50 = 12 μM) than the other DABT complexes. In addition, a molecular docking study was performed for DABT and its complexes to investigate their therapeutic features as topoisomerase inhibitors. It is clear that the most effective compound was DABT–Ni (II) complex to bind to 3QX3. Also, density functional theory calculations with the structure–activity relationship were computed for DABT and its complexes using the Gaussian program. There was confirmation between the obtained theoretical data and the experimental studies.

Extended characterization of anti-CD19 CAR T cell products manufactured at the point of care using the CliniMACS Prodigy system: comparison of donor sources and process duration

Background aimsThe CliniMACS Prodigy closed system is widely used for the manufacturing of chimeric antigen receptor T cells (CAR-T cells). Our study presents an extensive immunophenotypic and functional characterization and comparison of the properties of anti-CD19 CAR-T cell products obtained during long (11 days) and short (7 days) manufacturing cycles using the CliniMACS Prodigy system, as well as cell products manufactured from different donor sources of T lymphocytes: from patients, from patients who underwent HSCT, and from haploidentical donors. We also present the possibility of assessing the efficiency of transduction by an indirect method. MethodsSeventy-six CD19 CAR-T cell products were manufactured using the CliniMACS Prodigy automated system. Immunophenotypic properties, markers of cell activation and exhaustion, antitumor, anti-CD19 specific activity in vitro of the manufactured cell products were evaluated. As an indirect method for assessing the efficiency of transduction, we used the method of functional assessment of cytokine secretion and expression of the CD107a marker after incubation of CAR-T cells with tumor targets. ResultsThe CliniMACS Prodigy platform can produce a product of CD19 CAR-T cells with sufficient cell expansion (4.6 × 109 cells—median for long process [LP] and 1.6 × 109—for short process [SP]), transduction efficiency (43.5%—median for LP and 41.0%—for SP), represented mainly by T central memory cell population, with low expression of exhaustion markers, and with high specific antitumor activity in vitro. We did not find significant differences in the properties of the products obtained during the 7- and 11-day manufacturing cycles, which is in favor of reducing the duration of production to 7 days, which may accelerate CAR-T therapy. We have shown that donor sources for CAR-T manufacturing do not significantly affect the composition and functional properties of the cell product. ConclusionsThis study demonstrates the possibility of using the CliniMACS Prodigy system with a shortened 7-day production cycle to produce sufficient amount of functional CAR-T cells. CAR transduction efficiency can be measured indirectly via functional assays.

Studies on Differentially Expressed Genes of Tetrastigma hemsleyanum and Its Antitumor Activity

Objective: To analyze highly expressed genes in Tetrastigma hemsleyanum roots and the in vitro antitumor effects of extracts from different parts of this plant. Methods: The expression profiles of the roots, stems, and leaves of T hemsleyanum were analyzed via high-throughput sequencing technology with the Illumina Genome Analyzer platform. Then, gene ontology (GO) functional and pathway enrichment analyses of the significantly differentially expressed genes were performed. The inhibition rates of the extracts from different plant parts were determined through the CCK-8 method. Results: Genes related to catalytic activity and cytochrome P450 were upregulated in roots compared with leaves. The genes that we screened that were expressed at high levels in the roots may play an important role in the accumulation of active ingredients. GO functional enrichment analysis revealed that there were substantial differences in genes related to metabolic processes in roots compared with those in stems, and KEGG analysis revealed significant differences in genes related to the zeatin biosynthesis and diterpenoid biosynthesis pathways. Moreover, the expression of genes related to catalytic activity, ion binding, and hydrolase activity differed significantly between the roots and leaves, and KEGG analysis revealed significant differences in the expression of genes related to terpenoid biosynthesis and flavonoid biosynthesis pathways. Quantitative PCR indicated that Thhg was highly expressed in roots. The total triterpene content was also high in the tissue. The CCK-8 assays showed that the root ethanol extract had the highest antitumor activity. Conclusion: The genes we screened that were expressed at high levels in the roots may play an important role in the accumulation of active ingredients. Importantly, stem and leaf ethanol extracts also showed certain antitumor effects on human HCC Huh-7 and Hep3B cells in vitro and may also have medicinal value.

Dermatological toxicity in the treatment of malignant tumors in children: A review

Modern antitumor drugs have high antitumor activity. But only a number of them realize their antitumor effect in a targeted manner with minimal manifestations of concomitant toxicity. Damage to the skin and mucous membranes as part of the toxic effects of chemotherapy not only reduces the quality of life of patients, but can lead to disruption of the patient’s nutritional status, infection, and generalization of the infectious process with the development of sepsis. This review describes the major drugs that have dermatological toxicity, the main clinical variants of dermatological toxicity, methods for their prevention and treatment.

Перспективы применения иммуномодулирующих препаратов и модуляторов цереблон Е3-лигазы в лечении множественной миеломы

In recent decades, the progress in multiple myeloma (MM) treatment has been linked to a clearer insight into the biology of this disease and practical application of new pharmaceutical classes, such as immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs), and monoclonal antibodies (MABs). Modern IMiDs (lenalidomide and pomalidomide) are thalidomide derivatives which despite the similarity of chemical structure show only a relative cross-resistance. Lenalidomide is a second-generation immunomodulator with high anti-tumor activity and a favorable safety profile. In 2006, the use of lenalidomide combined with dexamethasone (Rd regimen) was approved by FDA (USA) for the treatment of relapsed/refractory MM, and 9 years later, in 2015, for newly diagnosed MM. During 2015–2019, the treatment of relapsed MM applied the newly developed regimens involving Rd combined with bortezomib (VRd), carfilzomib (KRd), ixazomib (IRd), elotuzumab (ERd), and daratumumab (DRd), the so-called triplets. Pomalidomide is a third-generation drug used in lenalidomide-refractory patients. For patients with relapsed/refractory MM who received at least two therapy lines with lenalidomide and bortezomib, regimens with 3 drugs were introduced which include pomalidomide and dexamethasone combined with elotuzumab (EPd), isatuximab (Isa-Pd), and daratumumab (DPd). In 2010, the molecular target of IMiD action was discovered, that is protein cereblon (CRBN), a component of CRBN E3 ligase enzyme complex. The insight into this mechanism provided the basis for developing a new family of thalidomide derivatives which are now called CRBN E3 ligase modulators (CELMoDs). In phase I/II trials, two drugs belonging to this group (iberdomide and mezigdomide) showed promising activity in MM refractory to three classes of antitumor drugs (IMiDs, PIs, and anti-CD38 MABs). The present review is focused on prospective studies of IMiDs and CELMoDs at different stages of MM treatment.

Artificial Water Channel Promoting Depolymerization of Actin Filaments to Trigger Cancer Cell Apoptosis

Comprehensive SummaryActin filaments play important physiological functions, which have become potential targets of antitumor drugs. Using chemicals to intervene their polymerization‐depolymerization dynamics would generate new strategies for designing antitumor drugs. In this report, an artificial water channel appending acetazolamide moiety, a ligand that can selectively bind to carbonic anhydrase IX, has been prepared. We demonstrated that this conjugate can target colorectal cancer cells overexpressing carbonic anhydrase IX and trigger the depolymerization of actin filaments of the cancer cells by selectively mediating water transmembrane transport. Moreover, the conjugate‐promoted actin depolymerization led to tumor cell apoptosis and its high antitumor activity in vitro and in vivo against colorectal cancer. The method described herein represents a new and general strategy for designing antitumor drugs by using artificial channel‐mediated selective water transport to promote actin depolymerization.

PM534, an Optimized Target-Protein Interaction Strategy through the Colchicine Site of Tubulin.

Targeting microtubules is the most effective wide-spectrum pharmacological strategy in antitumoral chemotherapy, and current research focuses on reducing main drawbacks: neurotoxicity and resistance. PM534 is a novel synthetic compound derived from the Structure-Activity-Relationship study on the natural molecule PM742, isolated from the sponge of the order Lithistida, family Theonellidae, genus Discodermia (du Bocage 1869). PM534 targets the entire colchicine binding domain of tubulin, covering four of the five centers of the pharmacophore model. Its nanomolar affinity and high retention time modulate a strikingly high antitumor activity that efficiently overrides two resistance mechanisms in cells (detoxification pumps and tubulin βIII isotype overexpression). Furthermore, PM534 induces significant inhibition of tumor growth in mouse xenograft models of human non-small cell lung cancer. Our results present PM534, a highly effective new compound in the preclinical evaluation that is currently in its first human Phase I clinical trial.

MOF@COF Nanocapsules Enhance Soft Tissue Sarcoma Treatment: Synergistic Effects of Photodynamic Therapy and PARP Inhibition on Tumor Growth Suppression and Immune Response Activation.

Soft tissue sarcomas (STS) are highly malignant tumors with limited treatment options owing to their heterogeneity and resistance to conventional therapies. Photodynamic therapy (PDT) and poly-ADP-ribose polymerase (PARP) inhibitors (PARPi) have shown potential for STS treatment, with PDT being effective for sarcomas located on the extremities and body surface and PARPi targeting defects in homologous recombination repair. To address the limitations of PDT and harness the potential of PARPi, herein, a novel therapeutic approach for STS treatment combining nanocapsules bearing integrated metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), i.e., MOF@COF, with PDT and PARPi is proposed. Nanocapsules are designed, referred to as ZTN@COF@poloxamer, which contain a Zr-based MOF and tetrakis (4-carbethoxyphenyl) porphyrin as a photosensitizer, are coated with a COF to improve the sensitizing properties, and are loaded with niraparib to inhibit DNA repair. Experiments demonstrate that this new nanocapsules treatment significantly inhibits STS growth, promotes tumor cell apoptosis, exhibits high antitumor activity with minimal side effects, activates the immune response of the tumor, and inhibits lung metastasis in vivo. Therefore, MOF@COF nanocapsules combined with PARPi offer a promising approach for STS treatment, with the potential to enhance the efficacy of PDT and prevent tumor recurrence.

Tumor resistance to anti-mesothelin CAR-T cells caused by binding to shed mesothelin is overcome by targeting a juxtamembrane epitope

Despite many clinical trials, CAR-T cells are not yet approved for human solid tumor therapy. One popular target is mesothelin (MSLN) which is highly expressed on the surface of about 30% of cancers including mesothelioma and cancers of the ovary, pancreas, and lung. MSLN is shed by proteases that cleave near the C terminus, leaving a short peptide attached to the cell. Most anti-MSLN antibodies bind to shed MSLN, which can prevent their binding to target cells. To overcome this limitation, we developed an antibody (15B6) that binds next to the membrane at the protease-sensitive region, does not bind to shed MSLN, and makes CAR-T cells that have much higher anti-tumor activity than a CAR-T that binds to shed MSLN. We have now humanized the Fv (h15B6), so the CAR-T can be used to treat patients and show that h15B6 CAR-T produces complete regressions in a hard-to-treat pancreatic cancer patient derived xenograft model, whereas CAR-T targeting a shed epitope (SS1) have no anti-tumor activity. In these pancreatic cancers, the h15B6 CAR-T replicates and replaces the cancer cells, whereas there are no CAR-T cells in the tumors receiving SS1 CAR-T. To determine the mechanism accounting for high activity, we used an OVCAR-8 intraperitoneal model to show that poorly active SS1-CAR-T cells are bound to shed MSLN, whereas highly active h15B6 CAR-T do not contain bound MSLN enabling them to bind to and kill cancer cells.

Effects of Medium Additives on the Mycelial Growth and Polysaccharide Biosynthesis in Submerged Culture of Bjerkandera fumosa.

Medium additives have been shown to affect the synthesis of active products in fungi. This study investigated the effects of corn stalk, poplar sawdust, Tween-80, and oleic acid on mycelial biomass and physicochemical properties, as well as the bioactivity of polysaccharides, including exopolysaccharides (EPS) and intracellular polysaccharides (IPS), in the submerged culture of Bjerkandera fumosa. Results showed that the addition of corn stalk or poplar sawdust increased the production of EPS but decreased the production of IPS; Tween-80 had less effect on the production of EPS and IPS; and oleic acid stimulated polysaccharide production significantly. Polysaccharide property analysis showed that the addition of corn stalk or poplar sawdust promoted the production of high-molecular-weight components in polysaccharides and changed the monosaccharide composition of polysaccharides, as well as increased the mannose, glucuronic acid, and xylose contents of IPS. Tween-80 and oleic acid also changed the molecular weight distribution of polysaccharides but only slightly affected the composition of monosaccharides. The bioactivity assay indicated that the polysaccharides obtained by adding corn stalk possessed high hydroxyl radical scavenging and antitumor activities. The effect of poplar sawdust was slightly weaker than that of corn stalk. EPS and IPS obtained from a culture with Tween-80 and oleic acid possessed low antioxidant activity. Moreover, their antitumor activity was improved and lost, respectively. The results obtained in this work are useful for improving the understanding of the optimization and regulation of bioactive polysaccharide production in the submerged culture of B. fumosa.

Anticancer effect of organotin complexes derived from 2,6-naphthalenedicarboxylic acid by enhancing the ROS generation

Enhancing ROS generation is crucial for anti-metastasis and anti-proliferation effects in anticancer chemotherapeutics. Herein, five organotin complexes [(Ph3Sn)2L] (1) [(R3Sn)2L]n (R = Et 2, R = n-Bu 3), [(n-Bu3Sn)2L(4,4′-bpe)]n (4), [(n-Bu3Sn)2L(4,4′-bipy)]n (5) were synthesized based on appropriate organotin precursors, 2,6-naphthalenedicarboxylic acid (H2L) and auxiliary ligand (4,4′-bipy = 4,4′-bipyridine, 4,4′-bpe = 1,2-di(4-pyridyl)ethylene). It was found that complex 1 exhibits a tetra-coordinated monomeric structure, complexes 2 and 3 show the 2D coordination polymer, and complexes 4 and 5 display the 1D chain with the central tin atoms as all penta-coordinated. These complexes showed high anti-tumor activity in vitro against four cancer cells (A549, HCT116, HepG-2 and HeLa), with IC50 values changed from 0.34±0.01 μM to 25.54 ± 1.55 μM. Additionally, complex 1 could be effective in inhibiting HepG-2 cell migration. Simultaneously, anticancer mechanism studies show that complex 1 induces excessive ROS production in HepG-2 cells, which in turn leads to the occurrence of ROS-induced downstream events, followed by the disintegration of the redox balance, depolarization of mitochondrial membrane potential, nucleus damage and ultimately apoptosis. This work suggests that enhancing the ability of organotin complexes to generate reactive oxygen species and disrupt intracellular redox balance may be a promising anticancer strategy.

Sufficiently activated mature natural killer cells derived from peripheral blood mononuclear cells substantially enhance antitumor activity.

Peripheral blood-derived natural killer (NK) cells spontaneously lyse tumor cells without prior sensitization. However, NK cells in peripheral blood (PBNK cells) are in a resting state and exhibit inhibitory phenotypes and impaired cytotoxicity. Thus, strengthening the cytotoxic effector function of PBNK cells and improving NK cell expansion in vitro for a convenient allogeneic therapy are essential. Pure cytokine activation and expansion of NK cells (super NK [SNK])from peripheral blood mononuclear cells were studied. Markers of activated and inhibited NK cells and cytokine secretion by NK cells were examined using flow cytometry. NK cell antitumor activity in vitro was assessed using lactate dehydrogenase (LDH) cytotoxicity assay and an Incucyte real-time imaging system. Additionally, the function of SNK cells against ascites caused by ovarian cancer in NOD-Prkdc(em26Cd52)il2rg(em26Cd22)/Nju (NCG)mice was determined. In a further investigation of the differences between PBNK and SNK, the mRNA of both cells was sequenced and analyzed. Human peripheral blood mononuclear cells showed selective NK cell expansion upon cytokine activation and culture. Both SNK and PBNK cells expressed activation markers, but at different levels, and SNK cells secreted more cytokines related to cytotoxicity than PBNK cells did. Accordingly, SNK cells exhibited strong antitumor activity ex vivo and improved NCG mice survival after intraperitoneal ovarian cancer transplantation. Mechanistically, SNK cells expressed more genes associated with nucleotide metabolism, fatty acid, and ATP metabolism than PBNK cells. SNK cells derived from peripheral blood mononuclear cells have sufficiently activated mature characteristics and high antitumor activity, rendering them a highly promising and essential therapeutic approach for cancer treatment.

Development of PROTACS degrading KRAS and SOS1.

The Kirsten rat sarcoma virus-son of sevenless 1 (KRAS-SOS1) axis drives tumor growth preferentially in pancreatic, colon, and lung cancer. Now, KRAS G12C mutated tumors can be successfully treated with inhibitors that covalently block the cysteine of the switch II binding pocket of KRAS. However, the range of other KRAS mutations is not amenable to treatment and the G12C-directed agents Sotorasib and Adragrasib show a response rate of only approximately 40%, lasting for a mean period of 8 months. One approach to increase the efficacy of inhibitors is their inclusion into proteolysis-targeting chimeras (PROTACs), which degrade the proteins of interest and exhibit much higher antitumor activity through multiple cycles of activity. Accordingly, PROTACs have been developed based on KRAS- or SOS1-directed inhibitors coupled to either von Hippel-Lindau (VHL) or Cereblon (CRBN) ligands that invoke the proteasomal degradation. Several of these PROTACs show increased activity in vitro and in vivo compared to their cognate inhibitors but their toxicity in normal tissues is not clear. The CRBN PROTACs containing thalidomide derivatives cannot be tested in experimental animals. Resistance to such PROTACS arises through downregulation or inactivation of CRBN or factors of the functional VHL E3 ubiquitin ligase. Although highly active KRAS and SOS1 PROTACs have been formulated their clinical application remains difficult.

Cytotoxicity and antitumor activity of sesquiterpene lactones. Structure, activity

The article discusses the results of 19 samples screening of sesquiterpene γ-lactones argolide, grosheimin, estafiatin, and their derivatives for cytotoxicity and antitumor activity. The research results indicate significant cytotoxicity and selectivity of the action of sesquiterpene γ-lactones and their derivatives against most tumor cell lines. Aim. The purpose of this study is to study the cytotoxicity and antitumor activity of the sesquiterpene γ-lactones argolide, grosheimin, estafiatin and their chemically modified derivatives, as practically renewable materials. Methods. The cytotoxicity of the compounds was determined using vero cells, THP-1, Pliss lymphosarcoma cell lines, Walker carcinosarcoma, sarcoma 45, sarcoma-180, alveolar liver cancer PC-1, P-388 leukemia, L-1210 leukemia, and resistant to 5-fluorouracil sarcoma 45. The antitumor activity of the samples was studied in in vivo experiments on white outbred rats with transplanted tumor strains and was assessed by inhibition of tumor growth and the magnitude of the increase in average life expectancy. Statistical processing of the results was carried out using the program “GraphPad Prism v. 6.0" (GraphPad Software Inc., USA). Conclusion. When determining cytotoxicity in in vitro samples of the sesquiterpene γ-lactones argolide, grosheimin, and estafiatin showed selectivity of their action on cells of 8 tumor lines, on cells of human acute monocytic leukemia THP-1 and in relation to the larvae of sea crustaceans Artemia salina (Leach). Samples of argolide, 8-acetylgrosheimin, 13-morpholinogrosheimin, 3-keto-4-methylene-cis-guaianolide, 3α-acetoxyisozaluzanin C, and 10α(14)-epoxy-1,5,7α,4,6β(H)-guai-11(13)-en-4(3),6(12)-diolide in experiments in vivo possessed high antitumor activity against transplantable tumor strains of Pliss lymphosarcoma, Walker carcinosarcoma, sarcoma 45, sarcoma 37, sarcoma 180, alveolar liver cancer PC-1, leukemia P-388 and L-1210, resistant to 5-fluorouracil sarcoma 45

The first representatives of phosphonium salts based on the ammonium acylhydrazone scaffold: synthesis and biological activity

The acid-catalyzed reaction of substituted benzaldehydes with Girard’s reagent T leads to the formation of new water-soluble mixed ammonium-phosphonium salts. The obtained compounds exhibit high antimicrobial and moderate antitumor activities with low hemotoxicity.

Post-Transplant Nivolumab Plus Unselected Autologous Lymphocytes in Truly Refractory Hodgkin Lymphoma Patients Is Highly Effective and Responses Are Mediated By NK Cells

Background In the relapsed/refractory Hodgkin Lymphoma (HL) setting (RHL), the achievement of complete remission (CR) is fundamental in order to proceed with allogeneic stem cell transplantation (HSCT) consolidation. Immune checkpoint inhibitors (CI) have demonstrated clinical activity in patients relapsing after ASCT, although only 20% CR rate is observed. In order to improve the efficacy of CI in RHL, we previously reported a salvage treatment based on early CI therapy following post-autologous stem cell transplantation (ASCT) with the reinfusion of unselected autologous lymphocytes infusions (ALI). The rationale of this approach is based on the achievement of a disease debulking through ASCT conditioning. Early administration of CI (nivolumab) is performed on a minimal disease burden, while reinfusions of ALI reduce post ASCT immune depression eliciting CI efficacy. Aims The aim of this study was to evaluate the efficacy of the procedure in terms of CR rates and overall survival (OS) after an extended follow up. Biological endpoint was to investigate the lymphocyte subpopulations involved in the mechanism of response and investigate the role of NK-cells mediating anti tumor responses in HL. Methods Patient were eligible to this study after failure to respond to first line treatment (i.e. positive PET2 or PET6 scan) and underwent autologous lymphocyte apheresis upon enrollment. All patients received conventional 2nd line chemo followed by 3rd line chemo-immunotherapy with Brentuximab-Vedotin (BV) in non-responding patients. Patient failing to achieve CR after BV were enrolled in the treatment arm and proceeded to ASCT + CI and ALI, whereas patients responding to 2nd- or 3rd treatment received ASCT followed by ALI alone, as a control cohort (figure 1A). NK cell degranulation assay was evaluated by staining for CD107a (LAMP-1) expression on healthy-donors derived NK cells exposed to HL cell lines (L428 and L250), in the presence or absence of monoclonal antibodies targeting inhibitory or activating receptors. Surface and intracellular staining was performed prior to flow cytometry and analysis was performed on the CD3-/CD56+ gated population. Results Twenty-one patients with RHL (median age 32 years; range 18-65) underwent lymphocyte apheresis after failure of 1st line chemo and then proceeded to salvage therapy. Thirteen patients failed to respond to 2nd and 3rd line therapy and thus received early post-transplant CI supported with four ALI. Eight patients responded to 2nd line chemo (n=6) or 3rd line BV (n=2) and received ASCT followed by ALI alone. No adverse events were recorded, specifically, no immune-related toxicity was observed. All patients receiving ALI + CI (treated patients) achieved negative PET scan CR. Eight of them received HSCT consolidation. One patient refusing HSCT after achieving CR in this study relapsed and responded to CI re treatment followed by HSCT. All patients in the treatment arm are alive and disease-free after a median follow-up of 32 months (95% CI 26.4-51.0). Median disease-free survival (DFS) was not reached in treatment arm (Fig 1B). Four of the patients in the control arm relapsed (50%). Three of them responded to 3rd line therapy and proceeded to HSCT. One patient achieved CR with conventional CI treatment but refused HSCT and the other relapsing patient died because of progressive lymphoma after failure to achieve CR with conventional single agent CI. Median DFS in the control arm was 22 months (Fig 1B). NK cells showed higher expansion and a faster maturation in the treatment arm, compared to the control arm (p<0.05). As expected, HL cells lines do not express HLA class I and II, but express activating NK cells receptors (aNKG2D, aNKp30, aNKp46, aDNAM-1). In vitro, the activation of each of those receptors was able to trigger NK cells degranulation. Similarly, PD-L1 and PD-L2 blockade on HL cell lines significantly increased NK cell degranulation (p<0.05). Taken together, those observations support the role of NK cells in this setting. Conclusions Our data show very high anti-tumor activity of ALI + CI for RHL, allowing most patients to proceed to HSCT. RHL patients in the treatment arm had an excellent outcome if compared to the control arm, which included patient who did respond to conventional treatment. Biological data suggests that this approach may accelerate NK cell development/maturation and suggest that NK cells may mediate response to CI in HL.