Profound Inhibition Research Articles

MG132-mediated Suppression of the Ubiquitin-proteasome Pathway Enhances the Sensitivity of Endometrial Cancer Cells to Cisplatin.

Tumor cell resistance to cisplatin is a common challenge in endometrial cancer chemotherapy, stemming from various mechanisms. Targeted therapies using proteasome inhibitors, such as MG132, have been investigated to enhance cisplatin sensitivity, potentially offering a novel treatment approach. The aim of this study was to investigate the effects of MG132 on cisplatin sensitivity in the human endometrial cancer (EC) cell line RL95-2, focusing on cell proliferation, apoptosis, and cell signaling. Human endometrial cancer RL95-2 cells were exposed to MG132, and cell viability was assessed in a dose-dependent manner. The study evaluated the effect of MG132 on cisplatin-induced proliferation inhibition and apoptosis, correlating with caspase-3 activation and reactive oxygen species (ROS) upregulation. Additionally, we examined the inhibition of the ubiquitin-proteasome system and the expression of pro-inflammatory cytokines IL-1β, IL-6, IL-8, and IL-13 during MG132 and cisplatin co-administration. MG132 exposure significantly reduced cell viability in a dose-dependent manner. It augmented cisplatin- induced proliferation inhibition and enhanced apoptosis, correlating with caspase-3 activation and ROS upregulation. Molecular analysis revealed a profound inhibition of the ubiquitin-proteasome system. MG132 also significantly increased the expression of cisplatin-induced pro-inflammatory cytokines, suggesting a transition from chronic to acute inflammation. MG132 enhances the therapeutic efficacy of cisplatin in human EC cells by suppressing the ubiquitin- proteasome pathway, reducing cell viability, enhancing apoptosis, and shifting the inflammatory response. These findings highlighted the potential of MG132 as an adjuvant in endometrial cancer chemotherapy. Further research is needed to explore detailed mechanisms and clinical applications of this combination therapy.

Development of a First-in-Class DNMT1/HDAC Inhibitor with Improved Therapeutic Potential and Potentiated Antitumor Immunity.

Epigenetic therapies have emerged as a key paradigm for treating malignancies. In this study, a series of DNMT1/HDAC dual inhibitors were obtained by fusing the key pharmacophores from DNMT1 inhibitors (DNMT1i) and HDAC inhibitors (HDACi). Among them, compound (R)-23a demonstrated significant DNMT1 and HDAC inhibition both in vitro and in cells and largely phenocopied the synergistic effects of combined DNMT1i and HDACi in reactivating epigenetically silenced tumor suppressor genes (TSGs). This translated into a profound tumor growth inhibition (TGI = 98%) of (R)-23a in an MV-4-11 xenograft model, while displaying improved tolerability compared with single agent combination. Moreover, in a syngeneic MC38 mouse colorectal tumor model, (R)-23a outperformed the combinatory treatment in reshaping the tumor immune microenvironment and inducing tumor regression. Collectively, the novel DNMT1/HDAC dual inhibitor (R)-23a effectively reverses the cancer-specific epigenetic abnormalities and holds great potential for further development into cancer therapeutic agents.

Transcriptomic analysis of MCF7 breast cancer cells treated with MGBs reveals a profound inhibition of estrogen receptor genes

Breast cancer poses a significant health risk worldwide. However, the effectiveness of current chemotherapy is limited due to increasing drug resistance and side effects, making it crucial to develop new compounds with novel mechanism of action that can surpass these limitations. As a consequence of their reversible and targeted mechanism, DNA minor groove binders (MGBs) are considered as a relatively safer and more effective alternative. In this study, transcriptomic analysis was conducted to reveal the dysregulated genes and signaling pathways in MCF7 cancer cells following treatment with novel MGB ligands to gain insights into the mechanism of action of MGBs at the molecular level. The transcriptomic results were validated using real-time PCR. The findings of this study indicate that the investigated MGBs primarily inhibit the genes associated with the estrogen receptor. Remarkably, ligand 5 showed downregulation of 34 out of the 35 genes regulated by estrogen receptor, highlighting its potential as a promising candidate for breast cancer therapy.

Restorer of fertility like 30, encoding a mitochondrion-localized pentatricopeptide repeat protein, regulates wood formation in poplar.

Nuclear-mitochondrial communication is crucial for plant growth, particularly in the context of cytoplasmic male sterility (CMS) repair mechanisms linked to mitochondrial genome mutations. The restorer of fertility-like (RFL) genes, known for their role in CMS restoration, remain largely unexplored in plant development. In this study, we focused on the evolutionary relationship of RFL family genes in poplar specifically within the dioecious Salicaceae plants. PtoRFL30 was identified to be preferentially expressed in stem vasculature, suggesting a distinct correlation with vascular cambium development. Transgenic poplar plants overexpressing PtoRFL30 exhibited a profound inhibition of vascular cambial activity and xylem development. Conversely, RNA interference-mediated knockdown of PtoRFL30 led to increased wood formation. Importantly, we revealed that PtoRFL30 plays a crucial role in maintaining mitochondrial functional homeostasis. Treatment with mitochondrial activity inhibitors delayed wood development in PtoRFL30-RNAi transgenic plants. Further investigations unveiled significant variations in auxin accumulation levels within vascular tissues of PtoRFL30-transgenic plants. Wood development anomalies resulting from PtoRFL30 overexpression and knockdown were rectified by NAA and NPA treatments, respectively. Our findings underscore the essential role of the PtoRFL30-mediated mitochondrion-auxin signaling module in wood formation, shedding light on the intricate nucleus-organelle communication during secondary vascular development.

One stone two birds: Endophytes alleviating trace elements accumulation and suppressing soilborne pathogen by stimulating plant growth, photosynthetic potential and defense related gene expression

In the present investigation, we utilized zinc nanoparticles (Zn-NPs) and bacterial endophytes to address the dual challenge of heavy metal (HM) toxicity in soil and Rhizoctonia solani causing root rot disease of tomato. The biocontrol potential of Bacillus subtilis and Bacillus amyloliquefaciens was harnessed, resulting in profound inhibition of R. solani mycelial growth and efficient detoxification of HM through strong production of various hydrolytic enzymes and metabolites. Surprisingly, Zn-NPs exhibited notable efficacy in suppressing mycelial growth and enhancing the seed germination (%) while Gas chromatography-mass spectrometry (GC-MS) analysis unveiled key volatile compounds (VOCs) crucial for the inhibition of pathogen. Greenhouse trials underscored significant reduction in the disease severity (%) and augmented biomass in biocontrol-mediated plants by improving photosynthesis-related attributes. Interestingly, Zn-NPs and biocontrol treatments enhanced the antioxidant enzymes and mitigate oxidative stress indicator by increasing H2O2 concentration. Field experiments corroborated these findings, with biocontrol-treated plants, particularly those receiving consortia-mediated treatments, displayed significant reduction in disease severity (%) and enhanced the fruit yield under field conditions. Root analysis confirmed the effective detoxification of HM, highlighting the eco-friendly potential of these endophytes and Zn-NPs as fungicide alternative for sustainable production that foster soil structure, biodiversity and promote plant health.

A rat model of multicompartmental traumatic injury and hemorrhagic shock induces bone marrow dysfunction and profound anemia.

Severe trauma is associated with systemic inflammation and organ dysfunction. Preclinical rodent trauma models are the mainstay of postinjury research but have been criticized for not fully replicating severe human trauma. The aim of this study was to create a rat model of multicompartmental injury which recreates profound traumatic injury. Male Sprague-Dawley rats were subjected to unilateral lung contusion and hemorrhagic shock (LCHS), multicompartmental polytrauma (PT) (unilateral lung contusion, hemorrhagic shock, cecectomy, bifemoral pseudofracture), or naïve controls. Weight, plasma toll-like receptor 4 (TLR4), hemoglobin, spleen to body weight ratio, bone marrow (BM) erythroid progenitor (CFU-GEMM, BFU-E, and CFU-E) growth, plasma granulocyte colony-stimulating factor (G-CSF) and right lung histologic injury were assessed on day 7, with significance defined as p values <0.05 (*). Polytrauma resulted in markedly more profound inhibition of weight gain compared to LCHS (p = 0.0002) along with elevated plasma TLR4 (p < 0.0001), lower hemoglobin (p < 0.0001), and enlarged spleen to body weight ratios (p = 0.004). Both LCHS and PT demonstrated suppression of CFU-E and BFU-E growth compared to naïve (p < 0.03, p < 0.01). Plasma G-CSF was elevated in PT compared to both naïve and LCHS (p < 0.0001, p = 0.02). LCHS and PT demonstrated significant histologic right lung injury with poor alveolar wall integrity and interstitial edema. Multicompartmental injury as described here establishes a reproducible model of multicompartmental injury with worsened anemia, splenic tissue enlargement, weight loss, and increased inflammatory activity compared to a less severe model. This may serve as a more effective model to recreate profound traumatic injury to replicate the human inflammatory response postinjury.

Inhibition of interferon regulatory factor 4 orchestrates T cell dysfunction, extending mouse cardiac allograft survival.

T cell dysfunction, which includes exhaustion, anergy, and senescence, is a distinct T cell differentiation state that occurs after antigen exposure. Although T cell dysfunction has been a cornerstone of cancer immunotherapy, its potential in transplant research, while not yet as extensively explored, is attracting growing interest. Interferon regulatory factor 4 (IRF4) has been shown to play a pivotal role in inducing T cell dysfunction. A novel ultra-low-dose combination of Trametinib and Rapamycin, targeting IRF4 inhibition, was employed to investigate T cell proliferation, apoptosis, cytokine secretion, expression of T-cell dysfunction-associated molecules, effects of MAPK and mammalian target of Rapamycin (mTOR) signaling pathways, and allograft survival in both in vitro and BALB/c to C57BL/6 mouse cardiac transplantation models. In vitro, blockade of IRF4 in T cells effectively inhibited T cell proliferation, increased apoptosis, and significantly upregulated the expression of programmed cell death protein 1 (PD-1), Helios, CD160, and cytotoxic T lymphocyte-associated antigen (CTLA-4), markers of T cell dysfunction. Furthermore, it suppressed the secretion of pro-inflammatory cytokines interferon (IFN)-γ and interleukin (IL)-17. Combining ultra-low-dose Trametinib (0.1mg·kg-1·day-1) and Rapamycin (0.1mg·kg-1·day-1) demonstrably extended graft survival, with 4 out of 5 mice exceeding 100 days post-transplantation. Moreover, analysis of grafts at day 7 confirmed sustained IFN regulatory factor 4 (IRF4) inhibition, enhanced PD-1 expression, and suppressed IFN-γ secretion, reinforcing the in vivo efficacy of this IRF4-targeting approach. The combination of Trametinib and Rapamycin synergistically inhibited the MAPK and mTOR signaling network, leading to a more pronounced suppression of IRF4 expression. Targeting IRF4, a key regulator of T cell dysfunction, presents a promising avenue for inducing transplant immune tolerance. In this study, we demonstrate that a novel ultra-low-dose combination of Trametinib and Rapamycin synergistically suppresses the MAPK and mTOR signaling network, leading to profound IRF4 inhibition, promoting allograft acceptance, and offering a potential new therapeutic strategy for improved transplant outcomes. However, further research is necessary to elucidate the underlying pharmacological mechanisms and facilitate translation to clinical practice.

The N-terminal domains of NLR immune receptors exhibit structural and functional similarities across divergent plant lineages.

Nucleotide-binding domain and leucine-rich repeat (NLR) proteins are a prominent class of intracellular immune receptors in plants. However, our understanding of plant NLR structure and function is limited to the evolutionarily young flowering plant clade. Here, we describe an extended spectrum of NLR diversity across divergent plant lineages and demonstrate the structural and functional similarities of N-terminal domains that trigger immune responses. We show that the broadly distributed coiled-coil (CC) and toll/interleukin-1 receptor (TIR) domain families of nonflowering plants retain immune-related functions through translineage activation of cell death in the angiosperm Nicotiana benthamiana. We further examined a CC subfamily specific to nonflowering lineages and uncovered an essential N-terminal MAEPL motif that is functionally comparable with motifs in resistosome-forming CC-NLRs. Consistent with a conserved role in immunity, the ectopic activation of CCMAEPL in the nonflowering liverwort Marchantia polymorpha led to profound growth inhibition, defense gene activation, and signatures of cell death. Moreover, comparative transcriptomic analyses of CCMAEPL activity delineated a common CC-mediated immune program shared across evolutionarily divergent nonflowering and flowering plants. Collectively, our findings highlight the ancestral nature of NLR-mediated immunity during plant evolution that dates its origin to at least ∼500 million years ago.

Immediate Platelet Inhibition Strategy for Comatose Out-of-Hospital Cardiac Arrest Survivors Undergoing Percutaneous Coronary Intervention and Mild Therapeutic Hypothermia.

Background: Comatose survivors of out-of-hospital cardiac arrest (OHCA) undergoing percutaneous coronary intervention (PCI) and target temperature management (TTM) are at increased risk of stent thrombosis (ST), partly due to delayed platelet inhibition even with more potent P2Y12 agents. We hypothesized that periprocedural cangrelor would induce immediate platelet inhibition, bridging the "P2Y12 inhibition gap". Methods: In our pilot study, we randomized 30 comatose OHCA patients undergoing PCI and TTM (32-34 °C) into cangrelor and control groups. Both groups received unfractioned heparin, acetylsalicylic acid, and ticagrelor via enteral tube. The cangrelor group also received an intravenous bolus of cangrelor followed by a 4 h infusion. Platelet inhibition was measured using VerifyNow® and Multiplate® ADP at baseline and 1, 3, 5, and 8 h post PCI. Results: Patient characteristics did not differ between groups. VerifyNow® showed significantly decreased platelet reactivity with cangrelor at 1 h (30 vs. 221 PRU; p < 0.001) and 3 h (24 vs. 180 PRU; p < 0.001), with differences at 5 and 8 h. Similarly, the proportion of patients with high on-treatment platelet reactivity (HPR) in the cangrelor group was significantly lower at 1 h (0% vs. 67%; p < 0.001) and 3 h (0% vs. 47%; p = 0.007). Multiplate® ADP was also decreased at 1 h (14 vs. 48 U; p < 0.001) and 3 h (11 vs. 42 U; p = 0.001), with no difference at 5 and 8 h. The occurrence of bleeding events was similar in both groups. Conclusions: Cangrelor safely induced immediate and profound platelet inhibition. We observed no significant drug-drug interaction with ticagrelor.

Evaluation of phytotoxicity, biochemical profiles, bioaccumulation hazard, and toxicity implications of battery manufacturing industrial discharge using a soilless cultivation system

This study has been devoted to the compositional evaluation of battery manufacturing industrial discharge (ID) and comprehensive assessment of: (i) plant vigor, chlorophylls contents, oxidative stress biomarkers; (ii) antioxidant defense system; (iii) non-enzymatic antioxidant responses; (iv) bioaccumulative profiles of toxic pollutants; and (v) in vitro genotoxicity and cytotoxicity of the four weeks ID-irrigated Ipomoea aquatica. Pb was identified as the dominating pollutant (5.35 mg/L) in the ID, with the accumulative profiles ranging from 0.002 to 1.36 mg/kg dry weight, in the descending order of root > shoot > leaf within Ipomoea aquatica. Profound inhibition of roots (26.60%) and shoots growth (20.53%), reduction of chlorophylls contents (39.81%), excessive-generation of superoxide anion (53.33%), hydrogen peroxide (55%), and lipid peroxidation (26.15%) were recorded. Antioxidant enzymes were up-regulated while the ferric reducing antioxidant power and radicals scavenging activities were concurrently enhanced. The in vitro toxicity of ID was verified by the significant dose-dependent increase in the mitochondrial respiratory inhibition associated-cell death and DNA destruction in the HepG2 cell (p < 0.05). These acquired findings have signified the threatening implications of Pb-contaminated ID-assisted irrigation on the sustainability of environmental and public health, and food security management.

Abstract 3304: Modulation of enhancer accessibility by SMARCA2 PROTACs synergize with TEAD inhibitors to suppress growth of SMARCA4 mutant lung cancers

Abstract The SWI/SNF chromatin remodeling complex is frequently mutated in non-small cell lung cancer with a frequency of 33% in advanced stage disease, making it the most commonly altered complex in lung cancer. Among the various subunits of the SWI/SNF complex, SMARCA4 and ARID1A are by far the most frequently mutated. Importantly, multiple clinical reports have shown that SMARCA4 mutant lung cancers have one of the worst prognosis among genetically defined lung cancer subtypes and lack response to both immunotherapy and KRAS G12C inhibitors. Recent reports, and our own data, have identified the paralogue SMARCA2 to be synthetic lethal to SMARCA4 suggesting SMARCA2 could be a high value therapeutic target. Unfortunately, the discovery of selective inhibitors of SMARCA2 has so far been challenging. To overcome this hurdle, we have recently developed novel, potent and selective SMARCA2 degrading small molecules based on proteolysis targeting chimera (PROTAC) technology. We demonstrated that YD23, our lead SMARCA2 PROTAC, potently and selectively induced degradation of SMARCA2. Importantly, we showed that YD23 selectively inhibits growth of SMARCA4 mutant lung cancer cells. Mechanistically, we demonstrated that YD23 decreased chromatin accessibility only in SMARCA4 deficient cells. In particular, SMARCA2 degradation profoundly decreased chromatin accessibility at enhancers of a number of genes with cell cycle and cell growth regulatory roles. Gene expression profiling and pathway analysis indicated that cell cycle genes were downregulated by YD23 consistent with the reduced chromatin accessibility at their cis-regulatory regions. We further showed that YD23 robustly inhibited growth of SMARCA4-mutant xenograft tumors. While this is promising, SMARCA2 degradation by itself does not induce regression of tumors highlighting the need for identification of efficacious combination strategies. Using integrative gene expression, ATAC-Seq and CUT&amp;RUN assays, we uncover a critical role for YAP/TEAD transcription factor signaling axis in mediating pro-growth phenotypes in SMARCA4 mutant tumors. Finally, we show that the combination of TEAD inhibitors synergizes with YD23 to induce profound tumor growth inhibition. In conclusion, our study provides a mechanistic basis for the anti-tumor action of SMARCA2 degraders and introduces a novel combination strategy for future clinical development against a genetically defined subtype of lung cancer with dismal prognosis. Citation Format: Sasi Kotagiri, Nicholas Blazanin, Mohammad Qudrattulah, Yuanxin Xi, Jing Wang, Yonathan Lissanu. Modulation of enhancer accessibility by SMARCA2 PROTACs synergize with TEAD inhibitors to suppress growth of SMARCA4 mutant lung cancers [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 3304.

Abstract 4596: Targeting arginine methylome in 9p21/MTAP-deleted malignant cancers with a next generation PRMT5-specific inhibitor CTS3497

Abstract It remains largely challenging to treat cancer patients with chromosome 9p21-deletion which occurs in approximately 15% of human cancers. Recently, specific targeting of protein arginine methyltransferase 5 (PRMT5), a key member of the type-II PRMT family and a master epigenetic modulator of arginine methylome essential for cancer progression, has emerged as a promising therapy in various hematological and solid tumors with MTAP deletion serving as a precision biomarker. To optimize the potential of targeting PRMT5, we developed CTS3497, a potent, brain-penetrable, orally bioavailable MTA-cooperative PRMT5 inhibitor, using our EpigenPLUSTM platform. The overall excellent drug-like properties of CTS3497 support fast track IND application, and it is anticipated to enter Phase 1 trials in 2024. CTS3497 demonstrated potent PRMT5 inhibitory activity in cellular pharmacodynamics (PD) assays, evidenced by the suppression of symmetric dimethylarginine (SDMA). Additionally, it exhibited profound cell growth inhibition with a low single-digit nM IC50 and 171-fold high selectivity for MTAPnull over isogenic MTAPwt cell lines. Moreover, CTS3497 displayed strong inhibitory effects on cell growth across diverse panels of MTAPnull cancer cell lines and patient-derived xenograft organoids (PDXOs) spanning various lineages. In vivo, oral administration of CTS3497 resulted in significant tumor regression in multiple MTAP-deleted xenograft models, notably MTAPnull brain tumors. The observed anti-tumor activity correlated with PRMT5 modulation, as indicated by reduced SDMA levels. Impressively, sustained tumor growth inhibition led to the complete tumor regression, with no regrowth even after discontinuation of CTS3497 treatment. The brain penetration property of CTS3497 underscores its therapeutic potential for both primary brain tumors, and brain metastases arising from specific cancers like lung cancer. At the molecular level, PRMT5 inhibition by CTS3497 induced substantial and distinctive RNA splicing defects and differentially expressed gene signatures, impacting key cellular activities downstream of arginine and epigenetic reprogramming in MTAPnull cancer cells. Furthermore, a synergistic anti-tumor effect was observed in multiple MTAP-deleted tumors when combining PRMT5 inhibition with CTS2190, an investigational type-I PRMT inhibitor currently in phase I/II clinical trials. In summary, CTS3497, a PRMT5 inhibitor selectively targeting MTAPnull tumor cells, demonstrated robust and durable anti-tumor responses both in vitro and in vivo across diverse lineages of MTAP-deleted tumors. Its superior ADME properties and favorable safety profiles observed in preclinical studies mark a breakthrough in the next generation epigenetic therapy. CTS3497 emerges as a promising therapeutic option for patients with MTAP-deleted malignancies. Citation Format: Yilin Liu, Long Wang, Hui Shi, Yuanyuan Liu, Qiugeng Ouyang, Xingnian Fu, Meng Wang, Jiannan Guo, Yiqin Wang, Youzhen Wang, Guoliang Xu, Yuan Mi, Haiping Wu. Targeting arginine methylome in 9p21/MTAP-deleted malignant cancers with a next generation PRMT5-specific inhibitor CTS3497 [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 4596.

Abstract 6050: Targeting KRAS G12D mutant tumors with the PROTAC degrader RP03707

Abstract RAS oncogene mutations are prevalent in approximately 19% of cancer patients, with the most frequent alteration occurring in codon 12 of the KRAS gene, resulting in a variety of G12X oncoproteins. Recent advances in drug discovery have yielded several KRAS G12C inhibitors currently in clinical use, benefiting a subset of patients. However, addressing the high-prevalence G12D mutation remains a substantial unmet medical need. Targeted protein degradation using PROTAC molecules offers a promising approach for treating KRAS G12D-associated tumors, potentially providing superior efficacy and mitigating the development of resistance, a challenge frequently observed with KRAS G12C inhibitors in clinical settings. In the present study, we report a PROTAC compound RP03707 that efficiently induces the degradation of the KRAS G12D mutant protein and inhibits tumor growth. Treatment of AsPc-1 cells with RP03707 results in significant degradation of the KRAS G12D protein, with a DC50 value in the sub-nanomolar range. Within 24 hours, the compound eliminates over 90% of G12D proteins and effectively suppresses downstream cellular MAPK signaling. Additional in vitro experiments demonstrate that RP03707 inhibits cell proliferation in multiple KRAS G12D mutant cell lines, surpassing the anti-tumor efficacy of enzyme inhibitors. In a mouse GP2d xenograft tumor model, a single intravenous administration of RP03707 at 10 mpk results in excellent compound penetration and retention in tumor tissues, followed by 90% reduction of G12D protein levels for 7 days. Profound inhibition of tumor growth is observed not only in mouse GP2d xenograft but also in other mouse KRAS G12D tumor models, even when the compound is administered in low and infrequent doses. Moreover, RP03707 exhibits high selectivity for degrading the KRAS G12D protein and possesses favorable drug-like properties. RP03707, therefore, meets the criteria for advancing into drug development and represents a valuable therapeutic option for treating KRAS G12D-associated tumors. Citation Format: Xiang Ji, Huanping Li, Gang Wu, Qiguo Zhang, Xiaolin He, Yanpeng Wu, Bing Zong, Xiaojin Xu, Chao Liang, Beibei Wang, Yuwei Zhang, Qingyao Hu, Jiaxin Zhou, Weihui Guo, Bing Bai, Lin Wang, Jinchao Ai, Leduo Zhang, Honggui Zhou, Shihao Sun, Yijie Wang, Youhong Wang, Qiming Fan, Dawei Chen, Tianlun Zhou, Jiasheng Lu. Targeting KRAS G12D mutant tumors with the PROTAC degrader RP03707 [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 6050.

Optimizing aspirin dose for colorectal cancer patients through deep phenotyping using novel biomarkers of drug action.

Background: Low-dose aspirin's mechanism of action for preventing colorectal cancer (CRC) is still debated, and the optimal dose remains uncertain. We aimed to optimize the aspirin dose for cancer prevention in CRC patients through deep phenotyping using innovative biomarkers for aspirin's action. Methods: We conducted a Phase II, open-label clinical trial in 34 CRC patients of both sexes randomized to receive enteric-coated aspirin 100mg/d, 100mg/BID, or 300mg/d for 3 ± 1weeks. Biomarkers were evaluated in blood, urine, and colorectal biopsies at baseline and after dosing with aspirin. Novel biomarkers of aspirin action were assessed in platelets and colorectal tissues using liquid chromatography-mass spectrometry to quantify the extent of cyclooxygenase (COX)-1 and COX-2 acetylation at Serine 529 and Serine 516, respectively. Results: All aspirin doses caused comparable % acetylation of platelet COX-1 at Serine 529 associated with similar profound inhibition of platelet-dependent thromboxane (TX)A2 generation ex vivo (serum TXB2) and in vivo (urinary TXM). TXB2 was significantly reduced in CRC tissue by aspirin 300mg/d and 100mg/BID, associated with comparable % acetylation of COX-1. Differently, 100mg/day showed a lower % acetylation of COX-1 in CRC tissue and no significant reduction of TXB2. Prostaglandin (PG)E2 biosynthesis in colorectal tumors and in vivo (urinary PGEM) remained unaffected by any dose of aspirin associated with the variable and low extent of COX-2 acetylation at Serine 516 in tumor tissue. Increased expression of tumor-promoting genes like VIM (vimentin) and TWIST1 (Twist Family BHLH Transcription Factor 1) vs. baseline was detected with 100mg/d of aspirin but not with the other two higher doses. Conclusion: In CRC patients, aspirin 300mg/d or 100mg/BID had comparable antiplatelet effects to aspirin 100mg/d, indicating similar inhibition of the platelet's contribution to cancer. However, aspirin 300mg/d and 100mg/BID can have additional anticancer effects by inhibiting cancerous tissue's TXA2 biosynthesis associated with a restraining impact on tumor-promoting gene expression. EUDRACT number: 2018-002101-65. Clinical Trial Registration: ClinicalTrials.gov, identifier NCT03957902.

Time Course of the Interaction Between Oral Short-Term Ritonavir Therapy with Three Factor Xa Inhibitors and the Activity of CYP2D6, CYP2C19, and CYP3A4 in Healthy Volunteers.

We investigated the effect of a 5-day low-dose ritonavir therapy, as it is used in the treatment of COVID-19 with nirmatrelvir/ritonavir, on the pharmacokinetics of three factor Xa inhibitors (FXaI). Concurrently, the time course of the activities of the cytochromes P450 (CYP) 3A4, 2C19, and 2D6 was assessed. In an open-label, fixed sequence clinical trial, the effect and duration of a 5-day oral ritonavir (100mg twice daily) treatment on the pharmacokinetics of three oral microdosed FXaI (rivaroxaban 25µg, apixaban 25µg, and edoxaban 50µg) and microdosed probe drugs (midazolam 25µg, yohimbine 50µg, and omeprazole 100µg) was evaluated in eight healthy volunteers. The plasma concentrations of all drugs were quantified using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods and pharmacokinetics were analysed using non-compartmental analyses. Ritonavir increased the exposure of apixaban, edoxaban, and rivaroxaban, but to a different extent the observed area under the plasma concentration-time curve (geometric mean ratio 1.29, 1.46, and 1.87, respectively). A strong CYP3A4 inhibition (geometric mean ratio >10), a moderate CYP2C19 induction 2days after ritonavir (0.64), and no alteration of CYP2D6 were observed. A CYP3A4 recovery half-life of 2.3days was determined. This trial with three microdosed FXaI suggests that at most the rivaroxaban dose should be reduced during short-term ritonavir, and only in patients receiving high maintenance doses. Thorough time series analyses demonstrated differential effects on three different drug-metabolising enzymes over time with immediate profound inhibition of CYP3A4 and only slow recovery after discontinuation. EudraCT number: 2021-006643-39.

Sonrotoclax overcomes BCL2 G101V mutation–induced venetoclax resistance in preclinical models of hematologic malignancy

AbstractVenetoclax, the first-generation inhibitor of the apoptosis regulator B-cell lymphoma 2 (BCL2), disrupts the interaction between BCL2 and proapoptotic proteins, promoting the apoptosis in malignant cells. Venetoclax is the mainstay of therapy for relapsed chronic lymphocytic leukemia and is under investigation in multiple clinical trials for the treatment of various cancers. Although venetoclax treatment can result in high rates of durable remission, relapse has been widely observed, indicating the emergence of drug resistance. The G101V mutation in BCL2 is frequently observed in patients who relapsed treated with venetoclax and sufficient to confer resistance to venetoclax by interfering with compound binding. Therefore, the development of next-generation BCL2 inhibitors to overcome drug resistance is urgently needed. In this study, we discovered that sonrotoclax, a potent and selective BCL2 inhibitor, demonstrates stronger cytotoxic activity in various hematologic cancer cells and more profound tumor growth inhibition in multiple hematologic tumor models than venetoclax. Notably, sonrotoclax effectively inhibits venetoclax-resistant BCL2 variants, such as G101V. The crystal structures of wild-type BCL2/BCL2 G101V in complex with sonrotoclax revealed that sonrotoclax adopts a novel binding mode within the P2 pocket of BCL2 and could explain why sonrotoclax maintains stronger potency than venetoclax against the G101V mutant. In summary, sonrotoclax emerges as a potential second-generation BCL2 inhibitor for the treatment of hematologic malignancies with the potential to overcome BCL2 mutation–induced venetoclax resistance. Sonrotoclax is currently under investigation in multiple clinical trials.

Neuroactivity screening of botanical extracts using microelectrode array (MEA) recordings

Toxicity testing of botanicals is challenging because of their chemical complexity and variability. Since botanicals may affect many different modes of action involved in neuronal function, we used microelectrode array (MEA) recordings of primary rat cortical cultures to screen 16 different botanical extracts for their effects on cell viability and neuronal network function in vitro. Our results demonstrate that extract materials (50 μg/mL) derived from goldenseal, milk thistle, tripterygium, and yohimbe decrease mitochondrial activity following 7 days exposure, indicative of cytotoxicity. Importantly, most botanical extracts alter neuronal network function following acute exposure. Extract materials (50 μg/mL) derived from aristolochia, ephedra, green tea, milk thistle, tripterygium, and usnea inhibit neuronal activity. Extracts of kava, kratom and yohimbe are particularly potent and induce a profound inhibition of neuronal activity at the low dose of 5 μg/mL. Extracts of blue cohosh, goldenseal and oleander cause intensification of the bursts. Aconite extract (5 μg/mL) evokes a clear hyperexcitation with a marked increase in the number of spikes and (network) bursts. The distinct activity patterns suggest that botanical extracts have diverse modes of action. Our combined data also highlight the applicability of MEA recordings for hazard identification and potency ranking of botanicals.

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.

Preparation, characterization and activity evaluation of Spirulina-chitooligosaccharides capable of inhibiting biofilms

The biofilms formed by pathogenic microorganisms seriously threaten human health and significantly enhance drug resistance, which urgently call for developing drugs specifically targeting on biofilms. Chitooligosaccharides extracted from shrimp and crab shells are natural alkaline oligosaccharides with excellent antibacterial effects. Nevertheless, their inhibition efficacy on biofilms still needs to be improved. Spirulina (SP) is a microalga with negatively charged surface, and its spiral structure facilitates colonization in the depth of the biofilm. Therefore, the complex of Spirulina and chitooligosaccharides may play a synergistic role in killing pathogens in the depth of biofilm. This research first screened chitooligosaccharides with significant bactericidal effects. Subsequently, Spirulina@Chitooligosaccharides (SP@COS complex was prepared by combining chitooligosaccharides with Spirulina through electrostatic adsorption. The binding of the complex was characterized by zeta potential, z-average size, and fluorescence labeling. Ultraviolet-visible spectroscopy (UV-Vis) showed the encapsulation efficiency and the drug loading efficiency reached up to 90% and 16%, respectively. The prepared SP@COS2 exhibited a profound synergistic inhibition effect on bacterial and fungal biofilms, which was mainly achieved by destroying the cell structure of the biofilm. These results demonstrate the potential of Spirulina-chitooligosaccharides complex as a biofilm inhibitor and provide a new idea for addressing the harm of pathogenic microorganisms.

ISGylation-independent protection of cell growth by USP18 following interferon stimulation.

Type 1 interferon stimulation highly up-regulates all elements of a ubiquitin-like conjugation system that leads to ISGylation of target proteins. An ISG15-specific member of the deubiquitylase family, USP18, is up-regulated in a co-ordinated manner. USP18 can also provide a negative feedback by inhibiting JAK-STAT signalling through protein interactions independently of DUB activity. Here, we provide an acute example of this phenomenon, whereby the early expression of USP18, post-interferon treatment of HCT116 colon cancer cells is sufficient to fully suppress the expression of the ISG15 E1 enzyme, UBA7. Stimulation of lung adenocarcinoma A549 cells with interferon reduces their growth rate but they remain viable. In contrast, A549 USP18 knock-out cells show similar growth characteristics under basal conditions, but upon interferon stimulation, a profound inhibition of cell growth is observed. We show that this contingency on USP18 is independent of ISGylation, suggesting non-catalytic functions are required for viability. We also demonstrate that global deISGylation kinetics are very slow compared with deubiquitylation. This is not influenced by USP18 expression, suggesting that enhanced ISGylation in USP18 KO cells reflects increased conjugating activity.