Potent Inhibitor Of Cell Growth Research Articles

An MDM2 degrader shows potent cytotoxicity to MDM2-overexpressing acute lymphoblastic leukemia cells with minimal toxicity to normal cells/tissues

The MDM2 oncogene is amplified and/or overexpressed in various human cancers and elevated expression of MDM2 protein acts as a survival factor promoting cancer progression through both p53-dependent and -independent pathways. Here, we report a novel small-molecule chemical compound (MX69-102) that we identified to induce MDM2 protein degradation, resulting in reactivation of p53, inhibition of XIAP, and potent cell growth inhibition and apoptosis in MDM2-overexpressing acute lymphoblastic leukemia (ALL) in vitro and in vivo. We have previously identified a compound (MX69) that binds to the MDM2 C-terminal RING domain and induces MDM2 protein degradation. In the present study, we performed structural modifications of MX69 and selected analog MX69-102, showing increased MDM2-targeting activity. MX69-102 exhibited significantly enhanced inhibitory and apoptotic effects on a group of MDM2-overexpressing ALL cell lines in vitro with IC50 values of about 0.2 μM, representing an approximately 38-fold increase in activity compared to MX69. MX69-102 also showed effective inhibition on xenografted human MDM2-overexpressing ALL in SCID mice. Importantly, MX69-102 had minimal or no inhibitory effect on normal human hematopoiesis in vitro and was very well tolerated in vivo in animal models. Based on the strong inhibitory and apoptotic activity against MDM2-overexpressing ALL, along with minimal or no toxicity to normal cells/tissues, MX69-102 is a candidate for further development as a novel MDM2-targeted therapeutic drug for refractory/MDM2-overexpressing ALL.

Antioxidant potential of alkaloids and polyphenols of Viola canescens wall using in vitro and in silico approaches.

Background: V. canescens Wall, a plant renowned for its ethno-medical properties, was investigated in this study for its antioxidant potential based on its wide therapeutic applications in traditional healthcare systems. The study aimed to assess the antioxidant potential of the plant extract/fractions and to predict the active phytochemicals using computational techniques. Methods: Five fractions were obtained from the crude methanolic extract of Viola canescens, and six concentrations (25, 50, 75, 100, 125, and 150μg/mL) were prepared for each fraction. The antioxidant activity of these fractions was evaluated using the Tetraoxomolybdate (VI) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. In-silico docking studies and molecular dynamic simulations were conducted to further elucidate the molecular interactions underlying the antioxidant activity. Results: The aqueous extract of V. canescens exhibited significant antioxidant and free radical scavenging activity against DPPH. Additionally, the crude flavonoid extract demonstrated moderate activity with IC50 value of 57.863μg/mL, indicating potent inhibition of cell growth. In-silico docking studies revealed a strong interaction between emetine and the aromatase protein, suggesting its potential as an antioxidant. Conclusion: The study findings highlight the antioxidant potential of V. canescens extract, indicating its suitability as a source of natural antioxidants. These results suggest its potential application in pharmaceutical preparations aimed at harnessing antioxidant properties for therapeutic purposes.

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.

Abstract 1664: Combination of LUNA18, a novel RAS inhibitor, with KRAS G12C inhibitors augments anti-tumor activity via inhibition of MAPK pathway reactivation

Abstract RAS gene alterations, found in approximately 15% of all cancers and known oncogenes, are recognized as promising therapeutic targets. KRAS G12C inhibitors were the first FDA-approved RAS targeting agent, but their efficacy of monotherapy is limited. Reactivation of the MAPK pathway is reported to be the one of the causes for attenuating efficacy of KRAS G12C inhibitors. LUNA18 is the cyclic peptide that binds to RAS mutants and wildtype, including KRAS, NRAS and HRAS, thereby inhibiting protein-protein interaction (PPI) between the inactive form of RAS and GEFs (guanine nucleotide exchange factors).We observed the rebound of ERK activation 24-72 hours after the treatment with a KRAS G12C inhibitor in cells with the KRAS G12C mutation though suppression of KRAS activity was maintained. This rebound was not suppressed by the KRAS G12C inhibitor retreatment. On the other hand, LUNA18 persistently suppressed ERK activity as well as KRAS activity up to 72 hours. LUNA18 also suppressed ERK reactivation caused by long-term treatment with the KRAS G12C inhibitor. The combination of the KRAS G12C inhibitor with siRNA for RAS wildtype showed durable inhibition of ERK activity, suggesting that RAS wildtype plays a key role for the rebound of ERK activity and inhibitory activity to RAS wildtype by LUNA18 contribute to the persistent inhibition of RAS signaling by LUNA18. In the experiment model that with strong RAS wildtype activation by stimulation with GFs (growth factors), the KRAS G12C inhibitor also did not suppress ERK activation. Conversely, LUNA18 suppressed it. Cell proliferation induced by GF stimulation was more strongly inhibited by LUNA18 than by the KRAS G12C inhibitors. Our data indicates that MAPK pathway reactivation via WT-RAS activation leads to resistance to KRAS G12C inhibitors and that the combination of LUNA18 and KRAS G12C inhibitors has the potential to overcome this resistance mechanism. In the in vitro cell growth assay, combination of LUNA18 and the KRAS G12C inhibitor showed more potent cell growth inhibition than single agents. We orally administered LUNA18 and the KRAS G12C inhibitor to a xenograft model, which showed temporal response and then acquired resistance to the KRAS G12C inhibitor, and found that LUNA18 significantly suppressed emergence of resistance to the KRAS G12C inhibitor. These results suggest that LUNA18 could be a promising candidate for combination therapy with KRAS G12C inhibitors. Citation Format: Saki Michisaka, Hitoshi Sase, Yukako Tachibana, Masami Hasegawa, Toshihiko Fujii, Shino Kuramoto, Norihito Shibahara, Atsushi Ohta, Mikihisa Tanada, Takuya Shiraishi, Hitoshi Iikura, Takehisa Kitazawa, Hiroshi Tanaka. Combination of LUNA18, a novel RAS inhibitor, with KRAS G12C inhibitors augments anti-tumor activity via inhibition of MAPK pathway reactivation [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 1664.

Abstract 4504: Discovery of CBPD-409 and CBPD-268 as highly potent and orally efficacious CBP/p300 PROTAC degraders for the treatment of castration-resistant prostate cancer

Abstract Prostate cancer remains the leading cause of cancer-related death globally in men. While current AR-targeted therapies are effective for the treatment of prostate cancer and improve patient survival, resistance in patients typically develops within 18 months. CBP/p300 are AR transcriptional co-activators and are promising therapeutic targets for the treatment of castration-resistant prostate cancer (CRPC). We developed a series of highly potent, selective, and orally efficacious CBP/p300 PROTAC degraders, with CBPD-409 being the best compound. CBPD-409 induces robust CBP/p300 degradation with DC50 0.2-0.4 nM and displays strong anti-proliferative effects with IC50 1.2-2.0 nM in VCaP, LNCaP and 22Rv1 AR+ cell lines. It has a favorable oral pharmacokinetic profile and achieves 50% of oral bioavailability in mice. A single oral administration of CBPD-409 at 1 mg/kg achieves >95% depletion of CBP/p300 proteins in the VCaP tumor tissue at 3 h and 24 h time points. CBPD-409 exhibits strong and dose/schedule-dependent tumor growth inhibition and is more potent and efficacious than two CBP/p300 inhibitors CCS1477 and GNE-049 and the AR antagonist Enzalutamide. To further improve the degradation potency and the oral bioavailability in rats, we developed a new class of CBP/p300 degraders based on our optimized CRBN ligand TX-16. Our efforts led to the discovery of CBPD-268 as an exceptionally potent, effective, and orally efficacious degrader of CBP/p300 proteins. In the VCaP, LNCaP and 22Rv1 cell lines, CBPD-268 induces consistent and robust CBP/p300 degradation with DC50 of ≤0.03 nM and Dmax >95%, leading to potent cell growth inhibition. CBPD-268 has excellent oral bioavailability in both mice and rats and has a good ADME profile. Oral administration of CBPD-268 at 0.3-3 mg/kg resulted in profound and persistent depletion of CBP and p300 proteins in tumor tissues and achieved strong antitumor activity in the VCaP and 22Rv1 xenograft tumor models in mice, including tumor regression in the VCaP tumor model. CBPD-268 was well tolerated in mice and rats and displayed a therapeutic index of >10. Taken together, CBPD-409 and CBPD-268 are highly promising CBP/p300 degraders for further extensive evaluations for the treatment of CRPC and other types of human cancers. Citation Format: Zhixiang Chen, Mi Wang, Dimin Wu, Lijie Zhao, Tianfeng Xu, Hoda Metwally, Yu Wang, Donna McEachern, Wei Jiang, Longchuan Bai, Jie Luo, Meilin Wang, Ruiting Li, John Takyi-Williams, Lu Wang, Qiuxia Li, Bo Wen, Duxin Sun, Arul M. Chinnaiyan, Shaomeng Wang. Discovery of CBPD-409 and CBPD-268 as highly potent and orally efficacious CBP/p300 PROTAC degraders for the treatment of castration-resistant prostate cancer [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 4504.

Inhibition of MALT1 and BCL2 Induces Synergistic Antitumor Activity in Models of B-Cell Lymphoma.

The activated B cell (ABC) subset of diffuse large B-cell lymphoma (DLBCL) is characterized by chronic B-cell receptor signaling and associated with poor outcomes when treated with standard therapy. In ABC-DLBCL, MALT1 is a core enzyme that is constitutively activated by stimulation of the B-cell receptor or gain-of-function mutations in upstream components of the signaling pathway, making it an attractive therapeutic target. We discovered a novel small-molecule inhibitor, ABBV-MALT1, that potently shuts down B-cell signaling selectively in ABC-DLBCL preclinical models leading to potent cell growth and xenograft inhibition. We also identified a rational combination partner for ABBV-MALT1 in the BCL2 inhibitor, venetoclax, which when combined significantly synergizes to elicit deep and durable responses in preclinical models. This work highlights the potential of ABBV-MALT1 monotherapy and combination with venetoclax as effective treatment options for patients with ABC-DLBCL.

Discovery of CBPD-268 as an Exceptionally Potent and Orally Efficacious CBP/p300 PROTAC Degrader Capable of Achieving Tumor Regression.

CBP/p300 proteins are key epigenetic regulators and promising targets for the treatment of castration-resistant prostate cancer and other types of human cancers. Herein, we report the discovery and characterization of CBPD-268 as an exceptionally potent, effective, and orally efficacious PROTAC degrader of CBP/p300 proteins. CBPD-268 induces CBP/p300 degradation in three androgen receptor-positive prostate cancer cell lines, with DC50 ≤ 0.03 nM and Dmax > 95%, leading to potent cell growth inhibition. It has an excellent oral bioavailability in mice and rats. Oral administration of CBPD-268 at 0.3-3 mg/kg resulted in profound and persistent CBP/p300 depletion in tumor tissues and achieved strong antitumor activity in the VCaP and 22Rv1 xenograft tumor models in mice, including tumor regression in the VCaP tumor model. CBPD-268 was well tolerated in mice and rats and displayed a therapeutic index of >10. Taking these results together, CBPD-268 is a highly promising CBP/p300 degrader as a potential new cancer therapy.

Discovery of Novel PROTAC Degraders of p300/CBP as Potential Therapeutics for Hepatocellular Carcinoma.

Adenoviral E1A binding protein 300 kDa (p300) and its closely related paralog CREB binding protein (CBP) are promising therapeutic targets for human cancer. Here, we report the first discovery of novel potent small-molecule PROTAC degraders of p300/CBP against hepatocellular carcinoma (HCC), one of the most common solid tumors. Based upon the clinical p300/CBP bromodomain inhibitor CCS1477, a conformational restriction strategy was used to optimize the linker to generate a series of PROTACs, culminating in the identification of QC-182. This compound effectively induces p300/CBP degradation in the SK-HEP-1 HCC cells in a dose-, time-, and ubiquitin-proteasome system-dependent manner. QC-182 significantly downregulates p300/CBP-associated transcriptome in HCC cells, leading to more potent cell growth inhibition compared to the parental inhibitors and the reported degrader dCBP-1. Notably, QC-182 potently depletes p300/CBP proteins in mouse SK-HEP-1 xenograft tumor tissue. QC-182 is a promising lead compound toward the development of p300/CBP-targeted HCC therapy.

Discovery of ASP6918, a KRAS G12C inhibitor: Synthesis and structure–activity relationships of 1-{2,7-diazaspiro[3.5]non-2-yl}prop-2-en-1-one derivatives as covalent inhibitors with good potency and oral activity for the treatment of solid tumors

Although KRAS protein had been classified as an undruggable target, inhibitors of KRAS G12C mutant protein were recently reported to show clinical efficacy in solid tumors. In our previous report, we identified 1-{2,7-diazaspiro[3.5]non-2-yl}prop-2-en-1-one derivative (1) as a KRAS G12C inhibitor that covalently binds to Cys12 of KRAS G12C protein. Compound 1 exhibited potent cellular pERK inhibition and cell growth inhibition against a KRAS G12C mutation-positive cell line and showed an antitumor effect on subcutaneous administration in an NCI-H1373 (KRAS G12C mutation-positive cell line) xenograft mouse model in a dose-dependent manner. In this report, we further optimized the substituents on the quinazoline scaffold based on the structure-based drug design from the co-crystal structure analysis of compound 1 and KRAS G12C to enhance in vitro activity. As a result, ASP6918 was found to exhibit extremely potent in vitro activity and induce dose-dependent tumor regression in an NCI-H1373 xenograft mouse model after oral administration.

Novel Inhibitors of MLLT1/3, a Critical Component of the Super-Elongation Complex (SEC), Target a Range of Molecularly Defined Acute Leukemias, with a Differential Profile to Menin Inhibition

Introduction: The SEC is a developmental transcriptional regulator which is often hijacked by cancer. The SEC regulates RNA Polymerase II dependent transcription of major oncogenes e.g., Myc, Bcl2, CDK6, along with developmental genes e.g. HOXA9 and MEIS1. SEC-dependent transcription is recognised as a driver in multiple acute myeloid leukemia (AML) sub-populations, such as those defined by Mixed Lineage Leukemia 1 (MLL1)-rearrangements (MLLr), which are prevalent in >10% of acute leukemias, and NPM1 mutations, which account for ~30% of leukemias. MLLT1 is known to be a key nucleating component of the SEC, and CRISPR/Cas-9 screens have previously highlighted a critical dependency for MLLT1 in MLLr driven leukemias. Clinical proof-of-concept for targeting the SEC has recently been demonstrated with inhibitors of menin, a protein that also impacts SEC activity in certain contexts. However, whilst the clinical data with menin inhibitors have been encouraging, there are a number of AML cell lines and patients that do not respond, and a growing number of examples of acquired clinical resistance. Hence there is a need for additional approaches which may benefit a broader spectrum of patients. Targeting MLLT1/3 provides one such promising approach. We have discovered novel MLLT1/3 inhibitors which have broad therapeutic potential across a range of molecularly defined acute leukemias, with a differential profile to menin inhibitors. Methods: In this study, a FRET assay was used to measure the ability of MLLT inhibitors to prevent the interaction of the MLLT1 and MLLT3 YEATS domains with acetylated histones. Selectivity was assessed against other YEATS domain proteins. MLLT target gene expression was measured by qPCR in leukemia cell lines. The anti-proliferative potential of MLLT1/3 inhibitors was assessed across a broad range of leukemia and normal cell lines and compared with menin inhibitors and other standard of care compounds using a cell viability readout (total ATP quantification). Combination studies were also performed in leukemia cell lines with MLLT1/3 and menin inhibitors. The clonogenic potential of MLLT1/3 inhibitors was determined using colony formation assays. Apoptosis was measured using caspase 3/7 readout. In vivo activity was assessed in a MV4;11 subcutaneous model. Results: We have identified novel MLLT1/3 inhibitors which block the interaction of the MLLT1 and 3 YEATS domains with acylated histones with IC 50 values <100 nM. They were shown to have excellent selectivity for MLLT1/3, with no inhibition observed against two other YEATS domain proteins, YEATS2 and 4. The MLLT1/3 inhibitors were shown to inhibit the expression of MLLT target genes known to be regulated via the SEC e.g., MYC and HOXA9. These compounds profoundly inhibited the growth of MLLr fusion and NPM1 mutant leukemias, with minimal activity seen against normal cell lines. Notably, potent inhibition of cell growth in non-MLLr fusion leukemia cell lines was observed, which were not sensitive to menin inhibition. MLLT1/3 inhibitors were shown to induce apoptosis and block the clonogenic potential of leukemia cell lines. Synergy between MLLT1/3 and menin inhibitors was also observed in leukemic cell lines. MLLT1/3 inhibitors have been tested in an MV4;11 model with substantial tumour growth inhibition observed. Conclusion: Targeting MLLT1/3 is an attractive approach and has the potential for single agent activity across a broad range of molecular defined acute leukemias, with a differential profile to menin inhibitors.

Preclinical Study of DZD8586, a Non-Covalent LYN/BTK Dual Inhibitor with Excellent BBB Penetration, for the Treatment of B-Cell Non-Hodgkin Lymphoma (B-NHL)

Introduction Bruton's Tyrosine Kinase (BTK) inhibitors have been approved for the treatment of B-NHL, such as CLL and MCL. However, resistance to BTK inhibitors still inevitably occurred, and different types of mutations were identified post covalent and non-covalent BTK inhibitor treatment. Although BTK inhibitors showed some activities in the treatment of relapsed or refractory non-germinal center B-cell (non-GCB) DLBCL, no drugs have been approved due to unsustainable tumor response. It is hypothesized that blockage of BTK pathway alone is not sufficient to achieve optimal anti-tumor efficacy in DLBCL. Due to limited blood-brain barrier (BBB) penetration of the current therapies, treatment of central nervous system lymphoma (CNSL) remains a clinical challenge. DZD8586 is a rationally designed, oral, non-covalent, LYN and BTK dual inhibitor with excellent BBB penetration as a potential treatment option for B-NHL. Here we report the preclinical activity of DZD8586 in lymphoma cell lines and animal models which supports its clinical development to address the above unmet medical needs. Methods The enzymatic activity of DZD8586 against multiple kinases was assessed at Eurofins panel with purified enzymes. TMD-8-IbruR cells carrying the C481S mutation were generated by stepwise induction of increasing concentrations of Ibrutinib. Cells carrying pirtobrutinib resistance mutations were obtained by transfection of different BTK mutations into RI-1 cells using lentivirus. Cell growth inhibition was determined by CellTiter-Glo. A pBTK enzyme-linked immunosorbent assay (ELISA) was used to evaluate the pharmacodynamic profile of DZD8586. Western blot was used to test the modulations of signaling pathways with DZD8586 treatment. Animal models were established by subcutaneous and intracranial inoculation of tumor cells, respectively, and animals were treated with DZD8586 or other BTK inhibitors. The anti-tumor efficacy was assessed by comparing the change in mean tumor volume between the different treatment groups and vehicle controls. Results Kinase panel profiling showed that DZD8586 potently inhibited LYN and BTK, with good selectivity against other kinases. In cell lines expressing C481X and pirtobrutinib resistance mutations, DZD8586 demonstrated concentration dependent anti-proliferative effects, with similar GI 50s among cells carrying different BTK mutations. In a panel of DLBCL cell lines, DZD8586 exhibited potent cell growth inhibition and induced cell death in a variety of cell lines, and its effect correlated with modulations of both LYN and BTK pathways. In both subcutaneous and CNS tumor models, DZD8586 exhibited profound tumor growth inhibition in a dose-dependent manner, and induced tumor regression at the doses of 50 mg/kg and above. There was a good correlation between plasma concentrations of DZD8586 and modulations of pBTK in whole blood and tumor tissue. DZD8586 has good cell permeability and is not significantly transported by P-gp and BCRP expressed at the BBB. The K puu,CSF of DZD8586 in rat and monkey were 1.2 and 1.3, respectively, suggesting its excellent BBB penetration in humans. Conclusion DZD8586 is a novel non-covalent LYN/BTK dual inhibitor, which could overcome resistance mutations to the approved covalent and non-covalent BTK inhibitors, and derive clinical benefit to patients with DLBCL and CNSL by blocking both BTK-dependent and BTK-independent signaling pathways with excellent BBB penetration.

Some Wild Mushrooms with High Antioxidant Capacity Exhibit Potent Anticancer Activity on Cancer Cells using the Apoptotic and Antimigration Cell Death Mechanisms.

This study aims to provide in vitro experimental evidence that wild mushrooms have the potential to be used as a pharmaceutical that could be effective against various types of cancer. Throughout human history, besides food, traditional medicine and natural poisons obtained from mushrooms have been used for the treatment of many diseases. Clearly, edible and medicinal mushroom preparations have beneficial health effects without the known severe adverse side effects. This study was designed to reveal the cell growth inhibitory potential of five different edible mushrooms and the biological activity of Lactarius zonarius was shown here for the first time. The mushrooms fruiting bodies were dried and powdered then extracted with hexane, ethyl acetate, and methanol. The mushroom extracts were screened for possible antioxidant activities by the free radical scavenging activity (DPPH) method. Antiproliferative activity and cytotoxicity of the extracts were investigated in vitro on A549 (human lung carcinoma), HeLa (human cervix carcinoma), HT29 (human colon carcinoma), Hep3B (human hepatoma), MCF7 (human breast cancer), FL (human amnion cells), and Beas2B (normal human cells) cells lines by using MTT cell proliferation assay, lactate dehydrogenase (LDH) assay, DNA degradation, TUNEL, and cell migration assay. Using proliferation, cytotoxicity, DNA degradation, TUNEL, and migration assay, we displayed that hexane, ethyl acetate, and methanol extracts of the Lactarius zonarius, Laetiporus sulphureus, Pholiota adiposa, Polyporus squamosus, and Ramaria flava were effective on the cells even so at low doses (< 45.0 - 99.6 µg/mL) by acting in a way that represses migration, as a negative inducer of apoptosis. It was also demonstrated that mushroom extracts with high antioxidant effect have within the acceptable cytotoxic activity of 20%-30% on the cell membrane at concentrations higher than 60 µg/mL. Overall, all of the mushroom extracts with high antioxidant effects had strong antiproliferative activity and low toxicity for cells. These findings, at least, highlight that these mushroom extracts can be used for the treatment of cancer disease, especially as a supportive therapy against colon, liver, and lung cancer.

Safety, Tolerability, and Antitumor Activity of Zipalertinib Among Patients With Non-Small-Cell Lung Cancer Harboring Epidermal Growth Factor Receptor Exon 20 Insertions.

Although several agents targeting epidermal growth factor receptor (EGFR) exon 20 insertions (ex20ins) have recently been approved by the US Food and Drug Administration, toxicities related to the inhibition of wild-type (WT) EGFR are common with these agents and affect overall tolerability. Zipalertinib (CLN-081, TAS6417) is an oral EGFR tyrosine kinase inhibitor (TKI) with a novel pyrrolopyrimidine scaffold leading to enhanced selectivity for EGFR ex20ins-mutant versus WT EGFR with potent inhibition of cell growth in EGFR ex20ins-positive cell lines. This phase 1/2a study of zipalertinib enrolled patients with recurrent or metastatic EGFR ex20ins-mutant non-small-cell lung cancer (NSCLC) previously treated with platinum-based chemotherapy. Seventy-three patients were treated with zipalertinib at dose levels including 30, 45, 65, 100, and 150 mg orally twice a day. Patients were predominantly female (56%), had a median age of 64 years, and were heavily pretreated (median previous systemic therapies 2, range 1-9). Thirty six percent of patients had received previous non-ex20ins EGFR TKIs and 3/73 (4.1%) patients received previous EGFR ex20ins TKIs. The most frequently reported treatment-related adverse events of any grade included rash (80%), paronychia (32%), diarrhea (30%), and fatigue (21%). No cases of grade 3 or higher drug-related rash or diarrhea were observed at 100 mg twice a day or below. Objective responses occurred across all zipalertinib dose levels tested, with confirmed partial response (PR) observed in 28/73 (38.4%) response-evaluable patients. Confirmed PRs were seen in 16/39 (41%) response-evaluable patients at the dose of 100 mg twice a day. Zipalertinib has encouraging preliminary antitumor activity in heavily pretreated patients with EGFR ex20ins-mutant NSCLC, with an acceptable safety profile, including low frequency of high-grade diarrhea and rash.

Discovery of the First Potent, Selective, and In Vivo Efficacious Polo-like Kinase 4 Proteolysis Targeting Chimera Degrader for the Treatment of TRIM37-Amplified Breast Cancer.

Polo-like kinase 4 (PLK4) is a master regulator of centriole replication and has been proposed as a therapeutic target for multiple cancers, especially TRIM37-amplified breast cancer. The development of novel and effective therapeutic strategies for TRIM37-amplified breast cancer therapy is challenging and extremely desirable. Herein, a structure-activity relationship (SAR) study with an emphasis on exploring different linker lengths and compositions was performed to report the discovery and characterization of SP27 as the first selective PLK4 proteolysis targeting chimera (PROTAC) degrader. SP27 exhibited effective PLK4 degradation, more potent inhibition of cell growth, and more efficient precision-therapeutic effect in the TRIM37-amplified MCF-7 cell line than conventional inhibitor CZS-035. Moreover, SP27 showed 149% bioavailability after intraperitoneal administration in PK studies and potent antitumor efficacy in vivo. The discovery of SP27 demonstrated the practicality and importance of PLK4 PROTAC and paved the way for studying PLK4-dependent biological functions and treat TRIM37-amplified breast cancer.

Abstract 470: A MDM2 degrader inhibits cell proliferation and growth of MDM2-overexpressing acute lymphoblastic leukemia in SCID mice

Abstract The MDM2 oncogene is amplified and/or overexpressed in various human cancers and elevated expression of MDM2 protein acts as a survival factor promoting cancer progression mainly through inhibition of the tumor suppressor p53. Here, we report a novel small-molecule chemical compound (MX69-114b) that we identified to induce MDM2 protein degradation resulting in reactivation of p53 and potent cell growth inhibition and apoptosis in MDM2-overexpressing acute lymphoblastic leukemia (ALL). We have previously identified a compound (MX69) that binds to the MDM2 C-terminal RING domain and induces MDM2 protein degradation. In the present study, we performed structural modification of MX69 and selected analog MX69-114b showing increased MDM2-targeting activity. MX69-114b exhibited significantly enhanced inhibitory and apoptotic effects on a group of MDM2-overexpressing ALL cell lines in vitro with IC50 values of 0.08-0.14 µM, representing a &amp;gt;80-100-fold increase in activity compared to MX69. MX69-114b also showed inhibitory effects on xenografted human MDM2-overexpressing ALL in SCID mice at a much lower dose than did MX69. Importantly, MX69-114b had minimal or no inhibitory effect on normal human hematopoiesis in vitro and was very well tolerated in vivo in animal models. Based on the strong inhibitory and apoptotic activity against MDM2-overexpressing ALL, along with minimal or no toxicity to normal cells/tissues, MX69-114b is a candidate for further development as a novel MDM2-targeted therapeutic drug for refractory ALL. Citation Format: tao Liu, Lubing Gu, Anna Mui, Zhongzhi Wu, Wei Li, Muxiang Zhou. A MDM2 degrader inhibits cell proliferation and growth of MDM2-overexpressing acute lymphoblastic leukemia in SCID mice [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 470.

Design, synthesis of novel benzimidazole derivatives as ENL inhibitors suppressing leukemia cells viability via downregulating the expression of MYC

Eleven-Nineteen-Leukemia Protein (ENL) containing YEATS domain, a potential drug target, has emerged as a reader of lysine acetylation. SGC-iMLLT bearing with benzimidazole scaffold was identified as an effective ENL inhibitor, but with weak activity against mixed-lineage leukemia (MLL)-rearranged cells proliferation. In this study, a series of compounds were designed and synthesized by structural optimization on SGC-iMLLT. All the compounds have been evaluated for their ENL inhibitory activities. The results showed that compounds 13, 23 and 28 are the most potential ones with the IC50 values of 14.5 ± 3.0 nM, 10.7 ± 5.3 nM, and 15.4 ± 2.2 nM, respectively, similar with that of SGC-iMLLT. They could interact with ENL protein and strengthen its thermal stability in vitro. Among them, compound 28 with methyl phenanthridinone moiety replacement of indazole in SGC-iMLLT, exhibited significantly inhibitory activities towards MV4-11 and MOLM-13 cell lines with IC50 values of 4.8 μM and 8.3 μM, respectively, exhibiting ∼7 folds and ∼9 folds more potent inhibition of cell growth than SGC-iMLLT. It could also increase the ENL thermal stability while SGC-iMLLT had no obvious effect on leukemia cells. Moreover, compound 28 could downregulate the expression of target gene MYC either alone or in combination with JQ-1 in cells, which was more effective than SGC-iMLLT. Besides, in vivo pharmacokinetic studies showed that the PK properties for compound 28 was much improved over that of SGC-iMLLT. These observations suggested compound 28 was a potential ligand for ENL-related MLL chemotherapy.

In Silico and In Vitro Study of Janus Kinases Inhibitors from Naphthoquinones.

Janus kinases (JAKs) are involved in numerous cellular signaling processes related to immune cell functions. JAK2 and JAK3 are associated with the pathogenesis of leukemia and common lymphoid-derived illnesses. JAK2/3 inhibitors could reduce the risk of various diseases by targeting this pathway. Herein, the naphthoquinones were experimentally and theoretically investigated to identify novel JAK2/3 inhibitors. Napabucasin and 2'-methyl napabucasin exhibited potent cell growth inhibition in TF1 (IC50 = 9.57 and 18.10 μM) and HEL (IC50 = 3.31 and 6.65 μM) erythroleukemia cell lines, and they significantly inhibited JAK2/3 kinase activity (in a nanomolar range) better than the known JAK inhibitor, tofacitinib. Flow cytometric analysis revealed that these two compounds induced apoptosis in TF1 cells in a time and dose-dependent manner. From the molecular dynamics study, both compounds formed hydrogen bonds with Y931 and L932 residues and hydrophobically contacted with the conserved hinge region, G loop, and catalytic loop of the JAK2. Our obtained results suggested that napabucasin and its methylated analog were potential candidates for further development of novel anticancer drug targeting JAKs.

Synthese und Biologische Untersuchungen von C(13)/C(13′)‐Bis(desmethyl)disorazol Z**

AbstractWir beschreiben hier die Totalsynthese des Makrodiolids C(13)/C(13′)‐Bis(desmethyl)disorazol Z über die Bildung des Makrozyklus durch eine doppelte inter‐/intramolekulare Stille‐Kreuzkupplung eines monomeren Vinylstannan/Vinyliodid Vorläufers. Der Schlüsselschritt in der Synthese dieses Vorläufers ist die stereoselektive Aldolreaktion eines formalen Evans Acetat‐Aldolprodukts mit Crotonaldehyd. Wie mitttels Röntgenkristallographie gezeigt werden konnte, ist der Bindungsmodus des C(13)/C(13′)‐Bis(desmethyl)disorazol Z an Tubulin praktisch identisch mit demjenigen des Naturstoffs Disorazol Z. Desgleichen unterdrückt das C(13)/C(13′)‐Bis(desmethyl)disorazol Z die Tubulinpolymerisation zumindest gleich stark wie das Disorazol Z und es hemmt das Zellwachstum offenbar sogar mit höherer Potenz.

Synthesis and Biological Evaluation of C(13)/C(13')-Bis(desmethyl)disorazole Z.

We describe the total synthesis of the macrodiolide C(13)/C(13')-bis(desmethyl)disorazole Z through double inter-/intramolecular Stille cross-coupling of a monomeric vinyl stannane/vinyl iodide precursor to form the macrocycle. The key step in the synthesis of this precursor was a stereoselective aldol reaction of a formal Evans acetate aldol product with crotonaldehyde. As demonstrated by X-ray crystallography, the binding mode of C(13)/C(13')-bis(desmethyl)disorazole Z to tubulin is virtually identical with that of the natural product disorazole Z. Likewise, C(13)/C(13')-bis(desmethyl)disorazole Z inhibits tubulin assembly with at least the same potency as disorazole Z and it appears to be a more potent cell growth inhibitor.

MYCN mRNA degradation and cancer suppression by a selective small-molecule inhibitor in MYCN-amplified neuroblastoma.

Amplification of the MYCN gene leads to its overexpression at both the mRNA and protein levels. Overexpression of MYCN mRNA may also have an important role in promoting neuroblastoma (NB) beyond the translation of MYCN protein. In the present study, we report a small molecule compound (MX25-1) that was able to bind to the 3'UTR of MYCN mRNA and induce MYCN mRNA degradation; this resulted in potent cell-growth inhibition and cell death specifically in MYCN-amplified or MYCN 3'UTR overexpressing NB cells. To evaluate the role of MYCN 3'UTR-mediated signals in contributing to the anticancer activity of MX25-1, we examined the status and activation of the tumor suppressor microRNA (miRNA) let-7, which is a target of MYCN 3'UTR in MYCN-amplified NB. We first observed that overexpression of MYCN mRNA was associated with high-level expression of the let-7 oncogenic targets DICER1, ARID3B and HMGA2. Following MYCN mRNA degradation, the expression of DICER1, ARID3B and HMGA2 was downregulated in MX25-1-treated cells. Inhibition of let-7 reversed the downregulation of these oncogenic mRNAs and significantly increased resistance of NB cells to MX25-1. Our results from this study supported the notion that overexpression of MYCN mRNA due to gene amplification has an independent function in NB cell growth and disease progression and suggest that targeting MYCN mRNA may represent an attractive strategy for therapy of MYCN amplified NB, both by inhibiting MYCN's cell-survival effects and activating the tumor-suppressor effect of let-7.