Hematological Tumor Cell Research Articles

Discovery of Novel 2-Aminopyridine-Based and 2-Aminopyrimidine-Based Derivatives as Potent CDK/HDAC Dual Inhibitors for the Treatment of Refractory Solid Tumors and Hematological Malignancies.

Co-inhibition of histone deacetylase (HDAC) and cyclin-dependent kinase (CDK) synergizes to produce enhanced antitumor effects and potentially overcomes the drug resistance. In this work, we discovered a series of novel CDK9/HDACs dual inhibitors. Among them, compound 8e was identified to show potent CDK9 and HDAC1 inhibitory activities, with IC50 values at 88.4 and 168.9 nM, respectively, and exhibited antiproliferative capacities against hematological and solid tumor cells. Meanwhile, 8e showed high selectivity for CDK9 and HDAC1, remarkably induced MV-4-11 cell apoptosis and S cell cycle arrests. Furthermore, 8e possessed a significant antitumor potency with a T/C value of 29.98% in the MV-4-11 xenograft model. Interestingly, a potent FLT3/HDAC dual inhibitor 9e was also identified (FLT3/HDAC1/3 IC50 = 30.4/52.4/14.7 nM) and found to possess powerful apoptosis induction ability in MV-4-11 cell and potent antiproliferative capacities against FLT3 mutant-transformed BaF3 cells. Overall, our work provided valuable lead compounds for dual inhibitors with potent anticancer activity.

Metabolic Function and Therapeutic Potential of CD147 for Hematological Malignancies: An Overview.

Hematological malignancies refer to a heterogeneous group of neoplastic conditions of lymphoid and hematopoietic tissues classified in leukemias, Hodgkin and non-Hodgkin lymphomas and multiple myeloma, according to their presumed cell of origin, genetic abnormalities, and clinical features. Metabolic adaptation and immune escape, which influence various cellular functions, including the proliferation and survival of hematological malignant tumor cells, are major aspects of these malignancies that lead to therapeutic drug resistance. Targeting specific metabolic pathways is emerging as a novel therapeutic strategy in hematopoietic neoplasms, particularly in acute myeloid leukemia and multiple myeloma. In this context, CD147, also known as extracellular matrix metalloproteinase inducer (EMMPRIN) or Basigin, is one target candidate involved in reprograming metabolism in different cancer cells, including hematological malignant tumor cells. CD147 overexpression significantly contributes to the metabolic transformation of these cancer cells, by mediating signaling pathway, growth, metastasis and metabolic reprogramming, through its interaction, direct or not, with various membrane proteins related to metabolic regulation, including monocarboxylate transporters, integrins, P-glycoprotein, and glucose transporter 1. This review explores the metabolic functions of CD147 and its impact on the tumor microenvironment, influencing the progression and neoplastic transformation of leukemias, myeloma, and lymphomas. Furthermore, we highlight new opportunities for the development of targeted therapies against CD147, potentially improving the treatment of hematologic malignancies.

Armored TGFβRIIDN ROR1-CAR T cells reject solid tumors and resist suppression by constitutively-expressed and treatment-induced TGFβ1

BackgroundChimeric antigen receptor (CAR) T-cell therapy target receptor tyrosine kinase-like orphan receptor 1 (ROR1) is broadly expressed in hematologic and solid tumors, however clinically-characterized ROR1-CAR T cells with single chain...

Abstract 617: BH-30236, a novel macrocyclic CLK inhibitor modulating RNA splicing, demonstrates potent inhibition of cancer cell growth in a broad panel of cancer cell lines

Abstract Alternative splicing (AS) is a primary mechanism for mRNA transcript diversification and protein expression regulation. In cancer, altered mRNA splicing promotes oncogenic transformation, induces metastasis, and confers resistance to cancer treatment. Mutations or imbalanced expression/activity of splicing factors (SF), such as serine-arginine-rich SFs (SRSFs), often result in deregulation of RNA splicing and tumor progression. CDC2-like kinases (CLK) and dual-specificity tyrosine-regulated kinase (DYRK) are key regulators of AS via phosphorylation of SRSFs. BH-30236 is a novel macrocyclic ATP-competitive inhibitor of CLK1/2/4. It also inhibits DYRK1/2, provirus integration site for moloney leukemia virus 3 (PIM3) and FMS-like tyrosine kinase 3 (FLT3) at clinically relevant concentrations. The inhibitory activity of BH-30236 against CLK, DYRK, PIM3 and FLT3 in cancer cells was investigated via the phosphorylation inhibition of SRSFs, Tau, 4EBP1 and FLT3, respectively. A panel of 119 hematological and solid tumor cell lines were used to investigate the spectrum of BH-30236 against cancer cell growth. To understand the mechanism of anti-cancer cell growth, the effect of BH-30236 on AS and protein expression of key tumor related biomarkers were examined. In conclusion, BH-30236 effectively inhibited pSRSF (IC50 40-60 nM in IMR-32 cells), pTau (IC50 ~50 nM in SH-SY5Y cells), p4EBP1 (IC50 ~80 nM in MM1S cells) and pFLT3-ITD (IC50 0.16 nM in MV-4-11 cells). BH-30236 demonstrated broad inhibition of cancer cell growth with a median IC50 of 85.2 nM (range 0.55-393 nM) across 12 tumor types. BH-30236 showed great efficacy against cell lines derived from hematological malignancy (median IC50 23.34 nM), neuroblastoma (median IC50 25.73 nM), breast cancer (median IC50 83.80 nM), colon cancer (median IC50 85.17 nM), and lung cancer (median IC50 102.65 nM). Furthermore, BH-30236 demonstrated synergy with KRAS inhibitors in KRAS mutant cell lines, with EGFR inhibitors in RBM10 mutant H1975 cells, and with BCL2 inhibitor Venetoclax in MOLM-13 cells. Mechanistically, BH-30236 modulated AS by increasing pro-apoptotic and anti-proliferative splicing variants of key factors, such as BCL2L1, S6K, and BCLAF1. Meanwhile, BH-30236 downregulated RNA expression of SRSFs and modulated BCL2 family to increase apoptosis. These results strongly support the clinical applications of the novel multikinase CLK inhibitor BH-30236 in hematological malignancies and solid tumors as a single agent or in combination with other therapies. Citation Format: Ping Jiang, Danan Li, Nancy Ling, Dayong Zhai, Wei Deng, Eugene Rui, J. Jean Cui. BH-30236, a novel macrocyclic CLK inhibitor modulating RNA splicing, demonstrates potent inhibition of cancer cell growth in a broad panel of cancer cell lines [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 617.

Current status and perspectives of gene therapy in the treatment of haematological cancers

Gene therapy holds great promise in the treatment of haematological cancers. Haematological cancers account for a significant portion of cancer cases worldwide, making gene therapy research in this area crucial. The emergence of breakthrough technologies, especially CRISPR-based gene editing, has enriched gene therapy possibilities and ushered in new opportunities for cancer treatment. Despite the potential benefits, gene therapy faces challenges related to safety and technical advancements. This work discusses practical applications of gene therapy, such as the use of monoclonal antibodies and gene transfer in haematological tumour cells. It also highlights the prospects of CRISPR gene editing technology, which has gained momentum in clinical applications for cancer treatment. However, it acknowledges potential risks and limitations, such as off-target effects and unpredictable translational outcomes. The conclusion emphasizes the need for further research to enhance long-term effectiveness, safety, and accessibility of gene therapy, using human genome sequencing, improved delivery technology, and better understanding of disease genes and biological mechanisms.

Serendipitous discovery of Class I HDAC inhibitors from rational design of molecular glue degraders targeting HDAC

Zinc-dependent histone deacetylases (HDACs) play an essential role as epigenetic regulators and are becoming increasingly important drug targets for the treatment of cancer. Although five HDAC inhibitors have been approved for treating several cancers, only one of them is a Class I HDAC inhibitor, which may have advantages over pan-HDAC inhibitors due to the various side effects associated with the latter. On the other hand, the emerging strategy of molecular glue degraders offers a unique advantage for targeting therapeutic proteins. In this study, we synthesized a series of candidate compounds based on the molecule glue, pomalidomide, using a “merger principle”, initially aiming to obtain molecular glue degraders that can target HDAC degradation. However, we serendipitously discovered that compounds 2f and 3f may be potent Class I HDAC selective inhibitors. After further evaluation, we found that compounds 2f and 3f exhibit selective inhibitory effects on Class I HDAC in cancer cells. Moreover, they showed the robust antiproliferative activities against various hematological tumor cells, comparable to that of the approved Class I HDAC inhibitor, Chidamide. These results suggest that pomalidomide-derivatized compounds have promising potential as Class I HDAC inhibitors with therapeutic applications in cancer treatment.

HDAC specificity and kinase off-targeting by purine-benzohydroxamate anti-hematological tumor agents

A series of hybrid inhibitors, combining pharmacophores of known kinase inhibitors bearing anilino-purines (ruxolitinib, ibrutinib) and benzohydroxamate HDAC inhibitors (nexturastat A), were generated in the present study. The compounds have been synthesized and tested against solid and hematological tumor cell lines. Compounds 4d-f were the most promising in cytotoxicity assays (IC50 ≤ 50 nM) vs. hematological cells and displayed moderate activity in solid tumor models (EC50 = 9.3–21.7 μM). Compound 4d potently inhibited multiple kinase targets of interest for anticancer effects, including JAK2, JAK3, HDAC1, and HDAC6. Molecular dynamics simulations showed that 4d has stable interactions with HDAC and members of the JAK family, with differences in the hinge binding energy conferring selectivity for JAK3 and JAK2 over JAK1. The kinase inhibition profile of compounds 4d-f allows selective cytotoxicity, with minimal effects on non-tumorigenic cells. Moreover, these compounds have favorable pharmacokinetic profiles, with high stability in human liver microsomes (e.g., see t1/2: >120 min for 4f), low intrinsic clearance, and lack of significant inhibition of four major CYP450 isoforms.

Developing “Off-the-Shelf” CLL1 CAR-DNT Therapeutics for the R/R Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) is one of the most common and highly heterogeneous hematological malignancy. The prognosis is poor especially for the elderly patients. For Relapsed/Refractory(R/R) AML patients, the one-year overall survival rate is merely 20%. CAR-T cells have shown tremendous therapeutic benefits for ALL, DLBCL and MM. One of the limitations of current CAR-T therapies is the use of autologous T cells. This can be limiting due to the cost, complicated manufacturing process, rapid disease progression, and manufacturing failures etc. Therefore, there is a need to develop the ready-to-use allogeneic cell product. Double negative T (DNT) cells are the ideal candidate for AML cell therapy as they naturally kill AML cells, and have been successfully administered to AML patients with therapeutic benefit without causing GvHD. Relying on their own natural immune activated receptors, DNT cells could lyse a wide range of tumors independent of TAA expression, which have more advantages compared to the conventional CAR-T cells. In our study, we developed the allogeneic product of CAR-DNT cells targeting C-type lectin-like molecule-1 (CLL1), which is a promising target due to its over-expression in primary AML cells and leukemia stem cells, while absence on hematopoietic stem/progenitor cells. Methods: We developed a humanized single chain variable fragment (scFv) with specific recognition of human CLL1 antigen by screening from 62 murine-derived CLL1 antibodies. Then, we designed a second-generation CLL1 CAR structure containing 4-1BB-CD3ζ and transduced it into the DNT cells by lentivirus. To clarify the GvH and HvG reactions of DNT cells, we performed the mixed lymphocyte reaction experiments in vitro and compared DNT cells with TCR and B2M double knockout T(DKO) cells and TCR knockout T(TKO) cells. We evaluated the anti-tumor function of CLL1 CAR-DNT cells through killing experiments by different effector-to-target ratios and multiple stimulations with AML cell lines (THP1 and HL60). Furthermore, we speculated that the CAR structure plays a critical role in both tumoricidal function and persistence of CAR-DNT cells. We designed nearly 20 enhanced CAR structures based on the signaling pathway of DNT cells. These newly designed structures have been tested in vitro and will be confirmed in vivo. Results: The humanized anti-CLL1 scFv candidate H1-3Q2 demonstrated high specificity toward human CLL1 antigen at the Membrane Protein Array. H1-3Q2 based CAR-T cells showed good tumor suppression in vivo. However, due to the heterogenous expression of CLL1 in AML, CLL1 CAR-T cells may not be able to eliminate AML cancer cells completely. While DNT cells could naturally lyse tumor cells through the receptors like NKG2D and DNAM-1, providing them with lots of advantages. Moreover, DNT cells have the potential to be used as allogenic cell therapy product. Co-culturing allogenic PBMCs or umbilical cord blood with DNT cells for up to 72 hours resulted in little or no killing reaction, indicated a low risk of GvHD. Conversely, the PBMCs from three different donors were used to attack allogenic DNT cells or DKO/TKO T cells in vitro. The killing effect on DKO/TKO T cells gradually increased over time, while no effect on DNT cells was observed even after 192 hours. This suggested that DNT cells are not easily cleared by host immune cells. DNT cells could efficiently lyse various hematological and solid tumor cell lines, particularly showing high sensitivity towards AML cells. The introduction of the CAR moiety further enhanced the specificity of DNT cells. The in vitro killing results demonstrated that CLL1 CAR-DNT cells exhibited stronger and faster AML resistance compared with CAR-T cells, and even eliminated tumor cells that have lost TAA. However, CLL1 CAR-DNT cells showed limited proliferation in the multiple-stimulation assays. To address this, we designed enhanced CAR structures. Screening by multiple-challenge assays, the fifth-generation CAR exhibited outstanding proliferation and superior tumor lysis ability in vitro. Conclusions: Our findings demonstrate that CAR-DNT product is an ideal candidate for allogeneic adoptive immunotherapy and exhibits superior tumoricidal function. This study underscores the potential of the “off-the-shelf” CLL1 CAR-DNT cell product for treating R/R AML.

The use of a new selective AB3 aptamer for the hematologic tumor cells’ detection

Hematologic malignancies represent cancer diseases that affect the bone marrow and blood cells and include various subtypes depending mostly on the morphology of the cells. It is well known that an early diagnosis could be very useful for increasing survival rates in cancer, especially in the aggressive forms which can quickly progress to untreatable forms. The development of an easy, fast, and sensitive analytical tool with indicative applications in diagnosis and follow-up care, that could bring benefits in the discovery of new malignant diseases or relapses is reported. Oncofetal antigen/immature laminin receptor protein (OFA/iLRP) is an immunogenic protein found in fetal cells as well as overexpressed on the surface of some malignant tumors, including some hematologic malignancies. An aptamer, AB3, was selected and reported in the literature, having as a target the immature laminin receptor protein. Using the AB3 aptamer and its affinity to immature laminin receptor protein-positive cells an aptasensor was developed and tested on Jurkat cells. For the immobilization of the aptamer, graphene oxide modified screen printed electrodes were used and subjected to an activation procedure. The aptasensor development and cell caption were evaluated using electrochemical methods as well as microscopic techniques. The limit of detection of the developed aptasensor was 3.3 × 103 cells mL−1, meaning 16 cells in the 5 µL of suspension tested.

Agaritine derived from Agaricus blazei Murrill induces apoptosis via mitochondrial membrane depolarization in hematological tumor cell lines.

Agaritine (AGT) is a hydrazine-containing compound derived from the mushroom Agaricus blazei Murill. We previously reported the antitumor effect of AGT on hematological tumor cell lines and suggested that AGT induces apoptosis in U937 cells via caspase activation. However, the antitumor mechanism of AGT has not been fully understood. Four hematological tumor cell lines (K562, HL60, THP-1, H929) were used in this study. The cells were incubated in the presence of 50μM AGT for 24h and analyzed for cell viability, annexin V positivity, caspase-3/7 activity, mitochondrial membrane depolarization, cell cycle, DNA fragmentation, and the expression of mitochondrial membrane-associated proteins (Bax and cytochrome c). In HL60, K562, and H929 cells, AGT reduced cell viability and increased annexin V- and dead cell-positive rates; however, it did not affect THP-1 cells. In K562 and HL60 cells, caspase-3/7 activity, mitochondrial membrane depolarization, and expression of mitochondrial membrane proteins, Bax and cytochrome c, were all increased by AGT. Cell cycle analysis showed that only K562 exhibited an increase in the proportion of cells in G2/M phase after the addition of AGT. DNA fragmentation was also observed after the addition of AGT. These results indicate that AGT induces apoptosis in K562 and HL60 cells, like U937 reported previously, but showed no effect on THP-1 cells. It was suggested that AGT-induced apoptosis involves the expression of Bax and cytochrome c via mitochondrial membrane depolarization.

Comparison of the Ways in Which Nitidine Chloride and Bufalin Induce Programmed Cell Death in Hematological Tumor Cells

The objective of this work to study the programmed cell death (PCD) in hematological tumor cells induced by nitidine chloride (NC) and bufalin (BF). Hematological tumor cells were exposed to various doses of NC and BF to measure the level of growth inhibition. While inverted microscope is used to observe cell morphology, western blot technique is used to detect apoptosis-related protein expression levels. The effects of NC and BF on hematological tumor cells were different. Although abnormal cell morphology could be seen under the inverted microscope, the western blot results showed that the two medicines induced PCD through different pathways. Drug resistance varied in intensity across distinct cells. THP-1, Jurkat, and RPMI-8226 each had half maximum inhibitory concentrations (IC50) of 36.23 nM, 26.71 nM, and 40.46 nM in BF, and 9.24 µM, 4.33 µM, and 28.18 µM in NC, respectively. Different hematopoietic malignancy cells exhibit varying degrees of drug resistance, and the mechanisms by which apoptosis of hematologic tumor cells is triggered by NC and BF are also distinct.

Abstract 6279: CTS2190, a next-generation epigenetic inhibitor for targeting type I PRMT deregulated human tumors

Abstract Methylation of arginine residues by protein arginine methyltransferases (PRMTs) is involved in the regulation of fundamental cellular processes. Type I PRMTs are frequently overexpressed in a variety of human cancers and associated with poor prognosis. Knockout (KO) of Prmt1 in mice results in decreased asymmetric dimethylarginine (ADMA) on cellular proteins, together with increased monomethylarginine (MMA) and symmetric dimethylarginine (SDMA) (Dhar et al., 2013). A structure-based drug discovery effort led to the identification of CTS2190 that showed single-digit nanomolar enzymatic inhibitory activity on type I PRMTs. Here, we report the development and preclinical characterization of CTS2190, a potent, orally bioavailable small molecule type I PRMT inhibitor. CTS2190 demonstrated strong cellular proliferation inhibitory activity in a large, diverse panel of human hematological and solid tumor cell lines across several lineages. In vivo, oral CTS2190 administration once daily resulted in tumor regression in a variety of xenograft (both CDX and PDX) models across different lineages with good tolerance. The anti-tumor activity was dose-dependent and correlated with the inhibition of type I PRMT activity as measured by decrease in ADMA and increase in MMA. In summary, CTS2190 is a promising type I PRMT inhibitor and clinical trial is underway to explore the proof-of-concept anti-tumor benefit for patients. Citation Format: Hui Shi, Xingnian Fu, Qiugeng Ouyang, Jiaxin Huang, Yiqin Wang, Youzhen Wang, Guoliang Xu, Yuan Mi, Haiping Wu. CTS2190, a next-generation epigenetic inhibitor for targeting type I PRMT deregulated human tumors. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6279.

Abstract 6298: A novel topoisomerase I inhibitor based anti-ICAM-1 antibody drug conjugate for the treatment of hematologic malignancies and solid tumors

Abstract Intercellular Cell Adhesion Molecule 1 (ICAM-1, CD54) is a type I transmembrane protein and a member of the immunoglobulin superfamily. ICAM-1 is involved in many key processes such as cell-cell interactions, signal transduction and leukocytes trans-endothelial migration. ICAM-1 is constitutively present at low levels on healthy tissues but highly expressed in some lymphoma, myeloma and some types of solid tumors including melanoma, non-small cell lung cancers and liver cancers. Previous attempt to target ICAM-1 with a monoclonal antibody bersanlimab (BI505, BioInvent) showed that it was well-tolerated but with limited clinical efficacy. To improve the effectiveness of targeting ICAM-1, we developed a novel ICAM-1 antibody drug conjugate (ADC). The ICAM-1 ADC is comprised of a humanized anti-ICAM-1 hIgG1 antibody conjugated to a novel topoisomerase I inhibitor through a cleavable linker at a drug-to-antibody ratio (DAR) of about 8. The antibody moiety of the ADC targets a unique epitope on ICAM-1 which is far from its ligand binding domain. Potent in vitro cytotoxicity of ICAM-1 ADC, with nanomolar to sub-nanomolar EC50, was observed on a panel of hematologic and solid tumor cell lines. In preclinical studies, one or two doses of ICAM-1 ADC at 5-6 mg/kg were generally sufficient to induce tumor regression in multiple cell line-derived xenograft models, including those of lung and liver cancers. In all models tested so far, the novel topoisomerase I inhibitor conjugated ICAM-1 ADC is at least as efficacious as the same ICAM-1 antibody conjugated to the benchmark topoisomerase I inhibitor linker payload deruxtecan (ICAM-1-DXd). Furthermore, in a repeat dose exploratory non-human primate safety study, the benchmark conjugate ICAM-1-DXd (DAR 8) was well-tolerated at 41 mg/kg, the highest dose tested. In conclusion, ICAM-1 is an attractive target for topoisomerase I inhibitor based ADC and warrants further investigation. Citation Format: Oi Kwan Wong, David Jackson, Lei Shi, Qi Fei, Xiaocheng Chen, Leonard Post. A novel topoisomerase I inhibitor based anti-ICAM-1 antibody drug conjugate for the treatment of hematologic malignancies and solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6298.

Abstract 1621: L105, a next generation of Bcl-2 inhibitor, overcomes Bcl-2 mutation and exhibits superior antitumor activity

Abstract Background: The Bcl-2 inhibitor venetoclax is approved for the treatment of chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL) and acute myeloid leukemia (AML). However, disease progression occurs when Ventoclax long-term treatment as a single agent driven by the recurrent Bcl-2 mutations, such as G101V, D103Y, D103E, et al. Here, we described the discovery of a next generation Bcl-2 inhibitor L105 with high potency against Bcl-2, Bcl-2(G101V) and Bcl-2(D103Y) for treatment of Bcl-2 dependent and venetoclax resistant hematological cancers. Methods: Biochemical inhibition assays were conducted by TR-FRET based assay. Proliferation inhibition assays on a panel of hematologic tumor cells were carried out by MTS assay. Caspase-3 activation in RS4;11 was determined by western blot. Preclinical pharmacokinetics studies were assayed in mice and dogs and parameters were determined by LC-MS. In vivo pharmacodynamic studies were performed in RS4;11 and OCI-LY10 derived xenograft SCID mouse models. In vitro human platelet toxicity was measured by CellTiter-Glo assay. Cytochrome P450 inhibition was measured in fluorometric assay. Results: In biochemical assays, the IC50 of L105 against Bcl-2 WT, Bcl-2 G101V, Bcl-2 D103Y, Bcl-2 D103E with IC50 of 0.42, 0.83, 0.97 and 5.78 nM respectively,while those of venetoclax were 1.89, 704.27, 470.19 and 243.30 nM respectively. In cellular assays, the IC50 of L105 in RS4;11, RS4;11 overexpressing Bcl-2 G101V, OCI-LY10, MV4-11, Mino, Toledo, Maver-1, SU-DHL-6 and REC-1 were 0.30-243.36 nM, while those of venetoclax were 2.91-3360.79 nM. L105 showed >2000 folds Bcl-2 selectivity over Bcl-xL. Furthermore, in vitro platelet viability assay showed L105 induced hypotoxicity at similar level of venetoclax. In pharmacodynamics studies, 5mpk L105 induced more rapid and robust antitumor effect in RS4;11 xenograft than venetoclax at 10 mpk did, and 15mpk L105 showed significant longer and stronger tumor suppression response than venetoclax at 25 mpk did. In the preclinical pharmacokinetic (PK) studies, L105 showed excellent PK properties in ICR mice and beagle dogs, in terms of long T1/2 and high dose-normalized AUC. L105 also exhibited a less drug-drug interaction potential, as no evidence on CYPs inhibition (IC50 >20 μM), while venetoclax potently inhibited CYP2C9 with IC50 at 1.12 μM. In 14-days oral gavage toxicity study in mice, no compound related deaths occurred at 15, 50 and 300 mpk, and only leukopenia was observed at similar level of venetoclax. Conclusions: L105 showed great potency on wild type and acquisition resistance mutations of Bcl-2, excellent oral bioavailability, and superior preclinical anti-tumor activities and safety profiles. It may provide new thoughts on treatment for a wide range of Bcl-2-dependent and Venetoclax-resistant hematological cancers. Citation Format: Xingguo Liu, Yang Lou, Yizhe Wu, Mingbo Su, Anhui Gao, Jinglai Huang, Li Zhong, Xinglu Zhou. L105, a next generation of Bcl-2 inhibitor, overcomes Bcl-2 mutation and exhibits superior antitumor activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1621.

Design, synthesis and biological evaluation of novel quinazolinone derivatives as CRBN E3 ligase modulators

CRBN E3 ligase modulators, also anteriorly called immunomodulatory drugs (IMiDs), exhibit excellent pharmacological activity by degrading cereblon (CRBN) associated multiple substrates and have become an important field for drug development. These modulators such as Thalidomide, Lenalidomide and CC-122 abduct CRBN to adhere to IKZF1/3 and other neosubstrates, and then induce the degradation of these substrates, thus retarding the further development of related diseases. Herein, we reported a series of CC-122 derivatives that inhibit the proliferation of hematological malignant tumor cell lines. Studies further confirmed that several derivatives which exhibit strong anti-proliferation effect induce the significant degradation of IKZF1/3. In addition, we found that the best compound 14 (SIAIS355035) exhibits better degradation activity and better anti-proliferation activities than CC-122, especially in diffuse large B lymphoma cell lines. Moreover, the PK properties of compound 14 are pretty promising with excellent oral bioavailability. These results clarified the SAR of CC-122 derivatives preliminarily and suggested that compound 14 has great value for further studies as an ideal novel CRBN E3 ligase modulation drug.

Chimeric Antigen Receptor-Natural Killer Cells: A New Breakthrough in the Treatment of Solid Tumours

Natural killer (NK) cells can quickly and directly eradicate tumour cells without recognising tumour-specific antigens. NK cells also participate in immune surveillance, which arouses great interest in the development of novel cancer therapies. The chimeric antigen receptor (CAR) family is composed of receptor proteins that give immune cells extra capabilities to target specific antigen proteins or enhance their killing effects. CAR-T cell therapy has achieved initial success in haematological tumours, but is prone to adverse reactions, especially with cytokine release syndrome in clinical applications. Currently, CAR-NK cell therapy has been shown to successfully kill haematological tumour cells with allogeneic NK cells in clinical trials without adverse reactions, proving its potential to become an off-the-shelf product with broad clinical application prospects. Meanwhile, clinical trials of CAR-NK cells for solid tumours are currently underway. Here we will focus on the latest advances in CAR-NK cells, including preclinical and clinical trials in solid tumours, the advantages and challenges of CAR-NK cell therapy and new strategies to improve the safety and efficacy of CAR-NK cell therapy.

A Phase1/1b Dose Escalation/Dose Expansion Study of Prgn-3007 Ultracar-T Cells in Patients with Advanced Hematologic and Solid Tumor Malignancies

Background: Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a promising target for cancer treatment as its expression enhances tumor cell growth and survival, promotes epithelial-mesenchymal transition and metastasis and participates in pro-survival pathways such as PI3-Kinase/AKT, EGFR signaling, and the p38-MAPkinase pathway. ROR1 is undetectable in normal adult tissues, however aberrant expression of ROR1 in malignancies has been detected in B-cell malignancies such as B-cell acute lymphoblastic leukemia (B-ALL), diffuse large cell B-cell lymphoma (DLBCL), chronic lymphocytic leukemia (CLL), and mantle cell lymphoma (MCL). Furthermore, upregulated expression has been detected in various solid tumors, including ovarian cancer, breast adenocarcinomas encompassing triple negative breast cancer (TNBC), pancreatic cancer, Ewing's sarcoma and lung adenocarcinoma. The increased expression of ROR1 in hematological and solid tumor malignancies has been associated with tumor proliferation, metastasis and poor clinical outcomes. The autologous UltraCAR-T® platform is designed to overcome the limitations of traditional CAR T which leads to an exhausted T cell phenotype, high manufacturing costs, and treatment delays, using advanced non-viral gene delivery system and a decentralized, overnight manufacturing process. Scientific Rationale: PRGN-3007 is built on Precigen's UltraCAR-T platform and is engineered to simultaneously express a ROR1-specific chimeric antigen receptor (ROR1 CAR); membrane bound interleukin-15 (mbIL15) for enhanced in vivo expansion and persistence; a kill switch for improved safety profile; and a novel mechanism for the intrinsic blockade of programmed cell death protein 1 (PD-1) gene expression. Preclinical studies with PRGN-3007 UltraCAR-T cells showed significant reduction in PD-1 expression with increased ROR1 specific cytotoxicity and inflammatory cytokine production upon co-culture with ROR1+ PD-L1+ hematological and solid tumor cells. Furthermore, PRGN-3007 was selectively and effectively eliminated by the kill switch activator antibody treatment. In vivo, a single administration of PRGN-3007, effectively reduced tumor burden and significantly improved overall survival (p<0.05) of tumor bearing mice compared to Control ROR1 CAR-T in an aggressive xenograft model of mantle cell lymphoma. Blood analyses demonstrated sustained downregulation of PD-1 expression, rapid expansion, long-term persistence, and a predominant central memory phenotype of PRGN-3007 in tumor bearing mice. (Blood (2021) 138 (Supplement 1): 1694.) Study Design: This is a first-in-human, Phase 1/1b dose escalation/dose expansion study to evaluate the safety and effectiveness of PRGN-3007 UltraCAR-T cells in patients with advanced ROR1-postive (ROR1+) hematologic (CLL, MCL, ALL, and DLBCL; Arm 1) and solid tumors (TNBC; Arm 2). Key inclusion criteria include absolute lymphocyte count ≥ 0.2k/µL, KPS > 70, adequate organ function, confirmed expression of ROR1 and: relapsed or refractory CLL; pathologically confirmed ALL B-cell precursor and measurable disease, pathologically confirmed MCL with overexpression of cyclin D1 or presence of t (11;14); pathologically confirmed DLBCL or high grade B-cell lymphoma including transformation from low grade lymphoma; or locally advanced unresectable or metastatic histologically confirmed TNBC with measurable disease as per RECIST 1.1. Study subjects undergo leukapheresis followed by lymphodepletion with either fludarabine 30mg/m2 and cyclophosphamide 500mg/m2 for 3 days (Arm 1) or 60 mg/kg cyclophosphamide for 2 days (Arm 2). The study will enroll in 2 phases: an initial dose escalation phase followed by a dose expansion phase. Up to 4 dose levels are planned in dose escalation phase (Table 1), and the MTD will be determined separately in subjects in the hematologic arm and the solid tumor arm. The MTD for each arm will be expanded independently in the dose expansion phase of the study. All subjects will be followed for adverse events, CAR-T-related toxicities, disease response and PRGN-3007 cell expansion and persistence. In addition, the mechanisms of safety and effectiveness of PRGN-3007 cells will be evaluated with correlative assays of specific immune response pathways. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Addressing the Enzyme-independent tumor-promoting function of NAMPT via PROTAC-mediated degradation

Aberrant overexpression of nicotinamide phosphoribosyltransferase (NAMPT) has been reported in a variety of tumor cells and is a poor prognosis factor for patient survival. It plays an important role in tumor cell proliferation, acting concurrently as an nicotinamide adenine dinucleotide (NAD+) synthase and, unexpectedly, as an extracellular signaling molecule for several tumor-promoting pathways. Although previous efforts to modulate NAMPT activity were limited to enzymatic inhibitors with low success in clinical studies, protein degradation offers the possibility to simultaneously disrupt NAMPT's enzyme activity and ligand capabilities. Here we report the development of two highly selective proteolysis-targeting chimeras (PROTACs) that promote NAMPT degradation in a cereblon-dependent manner. Both PROTAC degraders outperform a clinical candidate, FK866, in killing effect on hematological tumor cells. These results emphasize the importance and feasibility of applying PROTACs as a superior strategy for targeting proteins with multiple tumor-promoting functions like NAMPT, which is not easily achieved by conventional enzymatic inhibitors.

Research Progress of m6A Methylation Modification in Hematological Tumors--Review

N6-methyladenosine (m6A) is one of the most common epigenetic modifications of eukaryotic mRNAs, which is involved in the regulation of gene expressions and biological processes in a variety of cells with dynamic and reversible methylation processes. In recent years, many studies have shown that m6A methylation modification not only acts on the growth, proliferation, and medullary differentiation of acute myeloid leukemia cells, but also participates in the regulation of the proliferation and apoptosis of other hematological tumor cells such as chronic myeloid leukemia and diffuse large B-cell lymphoma, and it can even weaken the efficacy of anti-hematological tumor immunotherapy and induce immune escape leading to tumor resistance. With the successive development of a variety of m6A methylation-related enzyme inhibitors, it will provide new therapeutic ideas for patients with relapsed and refractory hematological tumors. In this paper, we review the research progress on the mechanism of m6A methylation on the occurrence, development, and tumor immunity of various hematological tumors.

Lisaftoclax (APG-2575) Is a Novel BCL-2 Inhibitor with Robust Antitumor Activity in Preclinical Models of Hematologic Malignancy.

Development of B-cell lymphoma 2 (BCL-2)-specific inhibitors poses unique challenges in drug design because of BCL-2 homology domain 3 (BH3) shared homology between BCL-2 family members and the shallow surface of their protein-protein interactions. We report herein discovery and extensive preclinical investigation of lisaftoclax (APG-2575). Computational modeling was used to design "lead" compounds. Biochemical binding, mitochondrial BH3 profiling, and cell-based viability or apoptosis assays were used to determine the selectivity and potency of BCL-2 inhibitor lisaftoclax. The antitumor effects of lisaftoclax were also evaluated in several xenograft models. Lisaftoclax selectively binds BCL-2 (Ki < 0.1 nmol/L), disrupts BCL-2:BIM complexes, and compromises mitochondrial outer membrane potential, culminating in BAX/BAK-dependent, caspase-mediated apoptosis. Lisaftoclax exerted strong antitumor activity in hematologic cancer cell lines and tumor cells from patients with chronic lymphocytic leukemia, multiple myeloma, or Waldenström macroglobulinemia. After lisaftoclax treatment, prodeath proteins BCL-2‒like protein 11 (BIM) and Noxa increased, and BIM translocated from cytosol to mitochondria. Consistent with these apoptotic activities, lisaftoclax entered malignant cells rapidly, reached plateau in 2 hours, and significantly downregulated mitochondrial respiratory function and ATP production. Furthermore, lisaftoclax inhibited tumor growth in xenograft models, correlating with caspase activation, poly (ADP-ribose) polymerase 1 cleavage, and pharmacokinetics of the compound. Lisaftoclax combined with rituximab or bendamustine/rituximab enhanced antitumor activity in vivo. These findings demonstrate that lisaftoclax is a novel, orally bioavailable BH3 mimetic BCL-2-selective inhibitor with considerable potential for the treatment of certain hematologic malignancies.