Actionable Therapeutic Target Research Articles

Predictors of hypercontractile heart phenotype in patients with chronic coronary syndromes

Abstract Background Hypercontractile phenotype of the left ventricle (LV) is an actionable therapeutic target in patients with chronic coronary syndromes (CCS), but its clinical recognition remains elusive. Purpose To assess the clinical variables associated with the hypercontractile phenotype of the LV, identified with supernormal values of an index of LV contractility such as LV force, also known as ventricular elastance. Methods In a prospective, observational, multicenter study, we recruited 5,122 patients (age 65± 11.1 years, 2974 males, 58%) with CCS referred for resting transthoracic echocardiography with technically successful volumetric echocardiography in 17 accredited laboratories. We measured systolic blood pressure (SBP) with a cuff sphygmomanometer. We assessed semi-quantitatively wall motion score index (WMSI), and quantitatively LV end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), force (SBP/ESV), stroke volume (SV), arterial elastance (SBP/SV), ventricular-arterial coupling (VAC, as SV/ESV), and cardiac output (CO = SV*heart rate).Univariable and multivariable logistic regression analysis assessed independent factors associated with the highest force sextile. Odds ratios (ORs) with the corresponding 95% confidence interval (CI) were estimated. Results For all the studied patients, EF was 59±11%. Force was 4.51±2.11 mmHg/ml, with reference sextile = 3.50-4.26 mmHg/ml, lowest sextile (Group 1) <2.60 mmHg/ml and highest sextile (Group 6) > 6.36 mmHg/ml. The correlation between the log of EF and the log of Force was significant with linear regression (r = 0.73, p < 0.001). Patients in the highest sextile of force showed lower values of WMSI, SV, EDV, and ESV, and higher values of arterial elastance and VAC (Table). By multivariable logistic regression model, the highest sextile of force was associated with age > 71 years (OR 4.35, 95% CI 3.06-6.18, p < 0.001), female sex (OR 4.48, 95% CI 3.62-5.54, p < 0.001), absence of beta-blocker therapy (OR 1.56, 95% CI 1.27-1.91), rest SBP> 159 mmHg (OR 6.86, 95% CI 5.03-9.35, p < 0.001), high heart rate (OR 1.03, 95% CI 1.02-1.04, p < 0.001), absence of prior MI (OR 1.31, 95% CI 1-1.72, p = 0.049), and higher LV EF at rest (OR 1.24, 95% CI 1.22-1.26, p < 0.001). Conclusions A hypercontractile phenotype of the LV with high force is associated with a small heart, reduced SV, and higher arterial elastance. It was clinically associated with advanced age, female sex, history of hypertension, absence of beta-blocker therapy, and high resting SBP.

The role of NOP58 in prostate cancer progression through SUMOylation regulation and drug response.

Prostate cancer is one of the leading causes of cancer-related deaths in men. Its molecular pathogenesis is closely linked to various genetic and epigenetic alterations, including posttranslational modifications like SUMOylation. Identifying biomarkers that predict outcomes and specific therapeutic targets depends on a comprehensive understanding of these processes. With growing interest in SUMOylation as a mechanism affecting prostate cancer-related genes, this study aimed to investigate the central role of SUMOylation in prostate cancer prognostics, focusing on the significance of NOP58. We conducted a comprehensive bioinformatics analysis, integrating differential expression analysis, survival analysis, gene set enrichment analysis (GSEA), and single-cell transcriptomic analyses using data from The Cancer Genome Atlas (TCGA). Key genes were identified through intersections of Venn diagrams, Boralta algorithm signatures, and machine learning models. These signaling mechanisms were validated through experimental studies, including immunohistochemical staining and gene ontology analyses. The dual-gene molecular subtype analysis with SUMO1, SUMO2, and XPO1 genes revealed significant differences in survival outcomes across molecular subtypes, further emphasizing the potential impact of NOP58 on SUMOylation, a key post-translational modification, in prostate cancer. NOP58 overexpression was strongly associated with shorter overall survival (OS), progression-free interval (PFI), and disease-specific death in prostate cancer patients. Immunohistochemical analysis confirmed that NOP58 was significantly overexpressed in prostate cancer tissues compared to normal tissues. ROC curve analysis demonstrated that NOP58 could distinguish prostate cancer from control samples with high diagnostic accuracy. Gene Ontology analysis, along with GSVA and GSEA, suggested that NOP58 may be involved in cell cycle regulation and DNA repair pathways. Moreover, NOP58 knockdown led to increased BCL2 expression and decreased Ki67 levels, promoting apoptosis and inhibiting cell proliferation. Colony formation assays further showed that NOP58 knockdown inhibited, while its overexpression promoted, colony formation, highlighting the critical role of NOP58 in prostate cancer cell growth and survival. Additionally, NOP58 was linked to drug responses, including Methotrexate, Rapamycin, Sorafenib, and Vorinostat. NOP58 is a key regulator of prostate cancer progression through its mediation of the SUMOylation pathway. Its expression level serves as a reliable prognostic biomarker and an actionable therapeutic target, advancing precision medicine for prostate cancer. Targeting NOP58 may enhance therapeutic efficacy and improve outcomes in oncology.

Predictors of hypercontractile heart phenotype in patients with chronic coronary syndromes or heart failure.

Hypercontractile phenotype (HP) of the left ventricle (LV) is an actionable therapeutic target in patients with chronic coronary syndromes (CCS) or heart failure (HF), but its clinical recognition remains difficult. To assess the clinical variables associated with the HP. In a prospective, observational, multicenter study, we recruited 5122 patients (age 65 ± 11years, 2974 males, 58%) with CCS and/or HF with preserved ejection fraction (EF). Systolic blood pressure (SBP) was measured. We assessed wall motion score index (WMSI), LV end-diastolic volume (EDV), end-systolic volume (ESV), EF, force (SBP/ESV), stroke volume (SV), arterial elastance (SBP/SV), and ventricular-arterial coupling (VAC, as SV/ESV). Univariable and multivariable logistic regression analysis assessed independent factors associated with the highest force sextile. For all the studied patients, force was 4.51 ± 2.11mmHg/ml, with the highest sextile (Group 6) > 6.36mmHg/ml. By multivariable logistic regression model, the highest sextile of force was associated with age > 65years (OR 1.62, 95% CI 1.36-1.93, p < 0.001), hypertension (OR 1.76, 95% CI 1.40-2.21, p < 0.001), female sex (OR 4.52, 95% CI 3.77-5.42, p < 0.001), absence of beta-blocker therapy (OR 1.41, 95% CI 1.16-1.68), rest SBP ≥ 160mmHg (OR 2.81, 95% CI 2.21-3.56, p < 0.001), high heart rate (OR 2.08, 95% CI 1.61-2.67, p < 0.001), and absence of prior myocardial infarction (OR 1.34, 95% CI 1.07-1.68, p = 0.012). Patients in the highest sextile of force showed lower values of WMSI, SV, EDV, and ESV, and higher values of arterial elastance and VAC. HP of the LV with high force was clinically associated with advanced age, female sex, high resting SBP, and the absence of β-blocker therapy. By transthoracic echocardiography, HP was associated with a small heart with reduced EDV, reduced SV despite high EF, and higher arterial elastance.

Pan-Cancer Interrogation of B7-H3 (CD276) as an Actionable Therapeutic Target Across Human Malignancies.

B7-H3-targeting therapeutics have shown promising results in initial clinical trials. In this pan-cancer analysis of B7-H3 mRNA expression, we found that B7-H3 exhibits robust expression in many common cancer types. These results may inform further development of B7-H3-targeting therapeutics and may guide clinical decisions for patients with limited treatment options.

Clinical Developments and Challenges in Treating FGFR2-Driven Gastric Cancer.

Recent advances in the treatment of gastric cancer (GC) with chemotherapy, immunotherapy, anti-angiogenic therapy and targeted therapies have yielded some improvement in survival outcomes; however, metastatic GC remains a lethal malignancy and amongst the leading causes of cancer-related mortality worldwide. Importantly, the ongoing molecular characterisation of GCs continues to uncover potentially actionable molecular targets. Among these, aberrant FGFR2-driven signalling, predominantly arising from FGFR2 amplification, occurs in approximately 3-11% of GCs. However, whilst several inhibitors of FGFR have been clinically tested to-date, there are currently no approved FGFR-directed therapies for GC. In this review, we summarise the significance of FGFR2 as an actionable therapeutic target in GC, examine the recent pre-clinical and clinical data supporting the use of small-molecule inhibitors, antibody-based therapies, as well as novel approaches such as proteolysis-targeting chimeras (PROTACs) for targeting FGFR2 in these tumours, and discuss the ongoing challenges and opportunities associated with their clinical development.

Induction of the Inflammasome Pathway by Tyrosine Kinase Inhibitors Provides an Actionable Therapeutic Target for Hepatocellular Carcinoma.

During the last decade, tyrosine kinase inhibitors (TKIs) sorafenib and regorafenib have been standard systemic treatments for advanced hepatocellular carcinoma (HCC). Previous data associated sorafenib with inflammasome activation. However, the role of the inflammasome in sorafenib and regorafenib signaling has not been described in liver cancer patients. For this purpose, we analyzed inflammasome-related transcriptomic changes in a murine HCC model. Our data confirmed inflammasome activation after both TKI treatments, sharing a similar pattern of increased gene expression. According to human database results, transcriptional increase of inflammasome genes is associated with poorer prognosis for male liver cancer patients, suggesting a sex-dependent role for inflammasome activation in HCC therapy. In biopsies of HCC and its surrounding tissue, we detected durable increases in the inflammasome activation pattern after sorafenib or regorafenib treatment in male patients. Further supporting its involvement in sorafenib action, inflammasome inhibition (MCC950) enhanced sorafenib anticancer activity in experimental HCC models, while no direct in vitro effect was observed in HCC cell lines. Moreover, activated human THP-1 macrophages released IL-1β after sorafenib administration, while 3D Hep3B spheres displayed increased tumor growth after IL-1β addition, pointing to the liver microenvironment as a key player in inflammasome action. In summary, our results unveil the inflammasome pathway as an actionable target in sorafenib or regorafenib therapy and associate an inflammasome signature in HCC and surrounding tissue with TKI administration. Therefore, targeting inflammasome activation, principally in male patients, could help to overcome sorafenib or regorafenib resistance and enhance the efficacy of TKI treatments in HCC.

Abstract 5922: Characterization of the biological effects of a quadruplex-interacting molecule in dedifferentiated liposarcoma cells

Abstract G-rich nucleic acid sequences can assume, under physiologic conditions, non-B secondary structures called G-quadruplexes (G4). The human genome contains thousands of putative quadruplex forming sequences (PQS), of which telomeres are the most extensively studied. PQS are frequently found in the promoters of oncogenes and transcription factors rather than in tumor suppressor or housekeeping genes, indicating an evolutionary selection of these elements based on gene function and suggesting a pivotal role of G4 in the regulation of gene expression. These observations have provided the rationale to explore G4 targeting as a therapeutic approach in cancer. Several small molecules have been indeed designed and characterized as G4-ligands (G4-L), most of them showing a “multiple-target” binding modality. Dedifferentiated liposarcoma (DDLPS) is a non-lipogenic disease characterized by aggressive local growth and multifocal local recurrences and the ability to elicit distant metastases. At the molecular level, DDLPS is marked by the amplification of the 12q13-q15 chromosomal region, leading to the abnormal expression of the MDM2 oncogene. The gene has emerged as an actionable therapeutic target and, recently, PQS within its promoter have been reported to fold into G4 structures. In addition, in our previous study, we observed that pathways related to telomere maintenance are remarkably up-modulated in DDLPS. These findings open a new avenue to explore the therapeutic potential of G4-L in this malignancy. In the present study, the biological activity of a tetra-substituted naphthalene diimide (NDI) G4-L derivative (SOP1812/QN-302) has been characterized in two patient-derived DDLPS cell lines. In particular, the exposure of DDLPS cells to increasing concentrations of SOP1812 resulted in a marked cytotoxic activity in vitro, with IC50 values within the sub-micromolar range (~0.3 μM). Moreover, DDLPS cells treated with equitoxic amounts of the compound were characterized by an 80-90% inhibition of telomerase activity and a remarkable perturbation in the MDM2-p53 feedback loop, leading to a pronounced accumulation of basal and phosphorylated (S15/S46/S392) p53 protein. These effects were paralleled by a 3-4 time increase in the number of γ-H2AX foci, the appearance of the cleaved form of PARP-1 and a pronounced inhibition of cell growth over time. Altogether, our findings indicate that targeting G4 structures by quadruplex-interacting molecules may represent a potential novel and effective therapeutic strategy in DDLPS. Citation Format: Eisa Naghshineh, Beatrice Tosoni, Lorenzo Di Pietro, Sandro Pasquali, Nadia Zaffaroni, Stephen Neidle, Sara N. Richter, Marco Folini. Characterization of the biological effects of a quadruplex-interacting molecule in dedifferentiated liposarcoma cells [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 5922.

Abstract 7089: Proteomic evaluation of combination data in acute myeloid leukemia to inform mechanism of action and new targets

Abstract Background: Acute myeloid leukemia (AML) is a prevalent adult leukemia. In the US, around 20,380 individuals were diagnosed with AML in 2023. Despite standard therapies, relapse and resistance persist. Cyclin-dependent kinase 9 (CDK9) has been recognized an actionable therapeutic target in AML. The potent inhibitor, AZD4573, induces durable apoptosis and suppresses tumor growth. Our study reveals that combining AZD4573 with standard-of-care (SoC) treatments deepens cell death responses in multiple AML cell models. We also used proteomics tools to understand the mechanisms underlying the vulnerability and resistance in SoC and CDK9 combinations. Methods: In the drug combination study, three SoC agents (cytarabine, decitabine, and venetoclax) were evaluated in combination using a 6 × 6 dose-response matrix in four AML cell models (MOLM13, MOLM16, MV411, and OCI-AML2). The HSA synergy score and Emax drug activity were used to assess the benefits of the drug combinations. In the proteomics evaluation study, MOLM13 cells treated for 7 days under different conditions - (1) vehicle control; (2) cytarabine alone; (3) decitabine alone; (4) venetoclax alone; (5) AZD4573 alone; (6) AZD4573+cytarabine; (7) AZD4573+decitabine; (8) AZD4573+venetoclax - were collected for proteomics analysis using LC-MS/MS. Differential expression and missing pattern analyses were used to identify dysregulated proteins. Functional enrichment analysis was employed to identify dysregulated biological processes and pathways in response to different treatments. Results: Our drug combination screens demonstrated the efficacy of AZD4573 in combination with cytarabine, decitabine, and venetoclax in 3 of 4 AML cell models. In our proteomic analysis, we took two approaches. First, we compared the proteomes of AML cells treated with SoC agents, identifying shared downregulated pathways such as serine biosynthesis, notably pointing to the rate-limiting enzyme PHGDH as a potential therapeutic target in AML. Cytarabine and decitabine induced an inflammatory response, while venetoclax increased the expression of cell division regulators like Aurora kinase B (AURKB). Interestingly, targeting AURKB with AZD2811 has been shown to overcome venetoclax resistance in AML. Second, we compared proteome changes induced by various AZD4573 combinations. We identified IRF2BP2 as a shared vulnerable protein across the three AZD4573 combinations. POUF2F2 expression was significantly induced by cytarabine but suppressed when combined with AZD4573. Given that POUF2F2 activates the PDK1-Akt pathway, our findings suggest that AZD4573-induced POUF2F2 downregulation suppresses the PDK1-AKT pathway, inhibiting tumor progression. Conclusions: Our proteomics analysis identifies vulnerable and resistant pathways and proteins, shedding light on the mechanism of action and revealing potential new targets for AML. Citation Format: Lori Chan, Zuleyha Ozen, Anthony Iannetta, Eric Miele, Funda Kar, Andrew Jarnuczak, Geoff Nelson, Aleksandra Markovets, Justine Roderick-Richardson, Jelena Urosevic, Lisa Drew, Jerome Mettetal. Proteomic evaluation of combination data in acute myeloid leukemia to inform mechanism of action and new targets [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 7089.

PRMT5 is an actionable therapeutic target in CDK4/6 inhibitor-resistant ER+/RB-deficient breast cancer

CDK4/6 inhibitors (CDK4/6i) have improved survival of patients with estrogen receptor-positive (ER+) breast cancer. However, patients treated with CDK4/6i eventually develop drug resistance and progress. RB1 loss-of-function alterations confer resistance to CDK4/6i, but the optimal therapy for these patients is unclear. Through a genome-wide CRISPR screen, we identify protein arginine methyltransferase 5 (PRMT5) as a molecular vulnerability in ER+/RB1-knockout breast cancer cells. Inhibition of PRMT5 blocks the G1-to-S transition in the cell cycle independent of RB, leading to growth arrest in RB1-knockout cells. Proteomics analysis uncovers fused in sarcoma (FUS) as a downstream effector of PRMT5. Inhibition of PRMT5 results in dissociation of FUS from RNA polymerase II, leading to hyperphosphorylation of serine 2 in RNA polymerase II, intron retention, and subsequent downregulation of proteins involved in DNA synthesis. Furthermore, treatment with the PRMT5 inhibitor pemrametostat and a selective ER degrader fulvestrant synergistically inhibits growth of ER+/RB-deficient cell-derived and patient-derived xenografts. These findings highlight dual ER and PRMT5 blockade as a potential therapeutic strategy to overcome resistance to CDK4/6i in ER+/RB-deficient breast cancer.

Disulfidptosis heterogeneity in breast cancer uncovers PTTG1IP as an actionable therapeutic target

Disulfidptosis heterogeneity in breast cancer uncovers PTTG1IP as an actionable therapeutic target

Oxidative Post-translational Protein Modifications upon Ischemia/Reperfusion Injury.

While reperfusion, or restoration of coronary blood flow in acute myocardial infarction, is a requisite for myocardial salvage, it can paradoxically induce a specific damage known as ischemia/reperfusion (I/R) injury. Our understanding of the precise pathophysiological molecular alterations leading to I/R remains limited. In this study, we conducted a comprehensive and unbiased time-course analysis of post-translational modifications (PTMs) in the post-reperfused myocardium of two different animal models (pig and mouse) and evaluated the effect of two different cardioprotective therapies (ischemic preconditioning and neutrophil depletion). In pigs, a first wave of irreversible oxidative damage was observed at the earliest reperfusion time (20 min), impacting proteins essential for cardiac contraction. A second wave, characterized by irreversible oxidation on different residues and reversible Cys oxidation, occurred at late stages (6-12 h), affecting mitochondrial, sarcomere, and inflammation-related proteins. Ischemic preconditioning mitigated the I/R damage caused by the late oxidative wave. In the mouse model, the two-phase pattern of oxidative damage was replicated, and neutrophil depletion mitigated the late wave of I/R-related damage by preventing both Cys reversible oxidation and irreversible oxidation. Altogether, these data identify protein PTMs occurring late after reperfusion as an actionable therapeutic target to reduce the impact of I/R injury.

Quantitative Membrane Proteomics for Discovery of Actionable Drug Targets at the Surface of RAS-Driven Human Cancer Cells.

With the advent of promising lung cancer immunotherapies targeting proteins at the cell surface of RAS-driven human cancers, the mass spectrometry (MS)-based surfaceomics remains a feasible strategy for therapeutic target discovery. This chapter describes a protocol for discovery of druggable protein targets at the surface of RAS-driven human cancer cells. This method relies on bottom-up MS-based quantitative surfaceomics that employs in parallel, targeted hydrazide-based cell-surface glycoproteomics and global shotgun membrane proteomics to enable unbiased quantitative profiling of thousands of cell surface membrane proteins. A large-scale molecular map of the KRASG12V surface was attained, resulting in confident detection and quantitation of more than 500 cell surface membrane proteins that were found to be unique or upregulated at the surface of cells harboring the KRASG12V mutant. A multistep bioinformatic progression revealed a subset of unique and/or significantly upregulated proteins as priority drug targets selected for orthogonal cross-validation using immunofluorescence, structured illumination microscopy, and western blotting. Among cross-validated targets, CUB domain containing protein 1 (CDCP1) and basigin (BSG-CD147) were selected as leading targets due to their involvement in cell adhesion and migration, consistent with the KRASG12V malignant phenotype as revealed by scanning electron microscopy and phenotypic cancer cell assays. Follow-up studies confirmed CDCP1 as an actionable therapeutic target, resulting in development of recombinant antibodies capable of killing KRAS-transformed cancer cells in preclinical setting. The present MS-based surfaceomics workflow represents a powerful drug target discovery platform that enables development of innovative immunotherapeutics (e.g., antibody drug conjugate against CDCP1) for attacking oncogenic RAS-driven cancers at the cell surface.

PSMC2 Overexpression Enhances Proteasome Activity, Mitigates ER Stress, and Correleates with Reduced Overall Survival in Multiple Myeloma

Background: Multiple myeloma (MM) remains a highly treatable but generally incurable plasma cell dyscrasia. These plasma cells synthesize massive amounts of paraprotein relying heavily on the ubiquitin proteasome system to maintain homeostasis and are exquisitely sensitive to proteasome inhibition to avoid terminal ER stress. We postulated that increased expression of clinically relevant proteasome subunits would correlate with reduced overall survival in MM patients treated with proteasome inhibitors. Objective: To correlate proteasome gene expression levels to clinicals outcomes in both the phase III APEX trial and the MMRF COMMPASS Trial. To model the effects of these hits on MMCL UPS function. Results: We identified that 19S regulatory ATPases PSMC2 and PSMC6 correlated with poorer OS, outperforming the proteasome inhibitor (PI) target, PSMB5, in this analysis. We focused on modeling the more frequently upregulated PSMC2. We created PSMC2 overexpressing multiple myeloma cell lines, noting PSMC2 is readily incorporated in the higher order proteasome complexes. PSMC2 overexpressing cells exhibit higher levels of 20S proteasome activity (1.6 fold increase in ARH77 and 3 fold increase in U266 cell line compared to control, p&amp;lt; 0.01 in each case) and are more resistant to PI challenge (Bortezomib LD 50 of 30 nM v 15 nM in U266 overexpressed and control cells respectively, Bortezomib LD 50 of 18 nM v 10 nM in ARH77 overexpressed v control cells respectively). PIs are known to increase ER stress, and PSMC2 overexpressing cells are better able to mitigate PI mediated ER stress with PSMC2 overexpressing cells exhibiting less induction of ER stress sensors p-IRE1α and ATF4 compared to PSMC2 knockdown cells on bortezomib or tunicamycin challenge as quantitated by western blotting and utilizing an fluorescent ER stress sensor that models the conversion of XBP1u to XBP1s by pIRE1α. Mechanistically, PSMC subunits play a key role in the recognition and degradation of misfolded ER proteins, and increased 19S subunits may allow more effective ER associated protein degradation (ERAD) Conclusions: Taken together, our results suggest PSMC2 overexpression correlates with reduced OS in MM patients treated with bortezomib and that PSMC2 may represent an actionable therapeutic target to prevent or overcome PI resistance. PSMC2 overexpression increases proteasome activity in MM cells, mitigates ER stress on PI challenge and promotes PI resistance. mitigates ER stress upon PI challenge, and portending poorer clinical prognosis and more drug resistance, suggesting that 19S targeted agents may help overcome drug resistance in MM. Figure 1 A. PSMC2 overexpression increases chymotrypsin-like proteasome activity at baseline in U266 and ARH77 cells with a similar effect of residual proteasome activity after challenge with bortezomib or carfilzomib. B. ARH77 and U266 FLAG and vector cells were challenged with bortezomib for 18 hrs and then assayed by annexin PI staining. LD50 increased from 10 nm to 15 nm in ARH77 cells and from 12 to 25 in U266 Cells.

OR05-03 Treatment Of Parathyroid Neoplasia By Pharmacologic cdk4/6 Inhibition

Abstract Disclosure: J. Costa-Guda: None. J. Bellizzi: None. S. Gorka: None. C. Titarenko: None. A. Arnold: None. Parathyroid carcinoma (PC) is a rare, life-threatening malignancy. Despite relatively slow growth, recurrent or metastatic disease is typically incurable and often fatal due to cumulative complications of sustained elevation of parathyroid hormone (PTH) and accompanying hypercalcemia. Medical therapy aids in managing sequelae of hyperparathyroidism (HPT) but non-surgical interventions to reduce tumor burden have been largely ineffective in PC. Cyclin D1 amplification is seen in nearly 30% of PC, making it a key potentially actionable therapeutic target. Importantly, in contrast to other tissue contexts, cyclin D1-driven parathyroid neoplasia has been experimentally demonstrated to depend on cyclin D1’s ability to bind and activate its partner cyclin dependent kinases (cdk). This suggests that parathyroid tumor cells may be more sensitive to alterations in cdk-mediated proliferation control, and thus more responsive to pharmacologic cdk inhibition, compared with other tumor types. We sought to test the efficacy of cdk4/6 inhibitor therapy in cyclin D1-overexpressing parathyroid tumors in a pre-clinical system. We utilized a mouse model, harboring a PTH-CCND1 (PCD) transgene to drive parathyroid-specific cyclin D1 overexpression, which develops hormonally-active parathyroid tumors with known kinetics. Transgenic mice with established hyperparathyroidism and wild type littermates were treated with the cdk4/6 inhibitors palbociclib or abemaciclib for three weeks. While vehicle-treated PCD mice showed a 7% increase in serum calcium (Ca) levels over the course of treatment, Ca decreased by 1.8% and 0.5% in palbociclib- and abemaciclib-treated PCD mice, respectively, from pre-treatment levels. This treatment effect persisted for at least 60 days after discontinuation of treatment. Decreased parathyroid proliferation, as evidenced by 4.7-fold and 17.3-fold fewer Ki-67-positive cells in palbociclib- and abemaciclib-treated PCD mice, respectively, compared with vehicle-treated PCD mice, was also seen. Cdk inhibitor treatment had no effect on Ca or parathyroid cell proliferation in wild type mice. These results demonstrate that palbociclib and abemaciclib can significantly slow the progression of hypercalcemia and parathyroid proliferation in a cyclin D1-driven parathyroid tumor model, suggesting that cyclin D1 overexpressing parathyroid cells may be particularly sensitive to cdk4/6 inhibition. Our findings provide the first evidence of a direct pharmacologic effect in a relevant preclinical system to support the hypothesis that selected HPT patients, eg those suffering from advanced PC with activated cyclin D1, could substantially benefit from cdk4/6 inhibitor therapy. This evidence may aid clinicians in selecting therapeutic interventions, including when considering such drugs for off-label use or inclusion of PC patients in “basket” clinical trials. Presentation: Thursday, June 15, 2023

P08 - Methionine Adenosyltransferase 2a (MAT2A) is a driver and an actionable therapeutic target in androgen-indifferent prostate tumors

P08 - Methionine Adenosyltransferase 2a (MAT2A) is a driver and an actionable therapeutic target in androgen-indifferent prostate tumors

Critical requirement of SOS1 for tumor development and microenvironment modulation in KRASG12D-driven lung adenocarcinoma

The impact of genetic ablation of SOS1 or SOS2 is evaluated in a murine model of KRASG12D-driven lung adenocarcinoma (LUAD). SOS2 ablation shows some protection during early stages but only SOS1 ablation causes significant, specific long term increase of survival/lifespan of the KRASG12D mice associated to markedly reduced tumor burden and reduced populations of cancer-associated fibroblasts, macrophages and T-lymphocytes in the lung tumor microenvironment (TME). SOS1 ablation also causes specific shrinkage and regression of LUAD tumoral masses and components of the TME in pre-established KRASG12D LUAD tumors. The critical requirement of SOS1 for KRASG12D-driven LUAD is further confirmed by means of intravenous tail injection of KRASG12D tumor cells into SOS1KO/KRASWT mice, or of SOS1-less, KRASG12D tumor cells into wildtype mice. In silico analyses of human lung cancer databases support also the dominant role of SOS1 regarding tumor development and survival in LUAD patients. Our data indicate that SOS1 is critically required for development of KRASG12D-driven LUAD and confirm the validity of this RAS-GEF activator as an actionable therapeutic target in KRAS mutant LUAD.

Evaluation of the interest to combine a CD4 Th1-inducer cancer vaccine derived from telomerase and atezolizumab plus bevacizumab in unresectable hepatocellular carcinoma: a randomized non-comparative phase II study (TERTIO – PRODIGE 82)

BackgroundSeveral cancer immunotherapies that target the PD-L1/PD-1 pathway show promising clinical activity in patients with hepatocellular carcinoma (HCC). However, the standard of care in first-line treatment with atezolizumab (anti-PD-L1 therapy) in combination with bevacizumab is associated with a limited objective response rate. Telomerase reverse transcriptase (TERT) activation meets the criteria of oncogenic addiction in HCC and could be actionable therapeutic target and a relevant tumor antigen. Therefore we hypothesized that combining anti-PD-1/PD-L1 therapy with an anti-telomerase vaccine might be an attractive therapy in HCC. UCPVax is a therapeutic cancer vaccine composed of two separate peptides derived from telomerase (human TERT). UCPVax has been evaluated in a multicenter phase I/II study in non–small cell lung cancers and has demonstrated to be safe and immunogenic, and is under evaluation in combination with atezolizumab in a phase II clinical trial in tumors where telomerase reactivation contributes to an oncogene addiction (HPV+ cancers). The aim of the TERTIO study is to determine the clinical interest and immunological efficacy of a treatment combining the CD4 helper T-inducer cancer anti-telomerase vaccine (UCPVax) with atezolizumab and bevacizumab in unresectable HCC in a multicenter randomized phase II study.MethodsPatients with locally advanced, metastatic or unresectable HCC who have not previously received systemic anti-cancer treatment are eligible. The primary end point is the objective response rate at 6 months. Patients will be allocated to a treatment arm with a randomization 2:1. In both arms, patients will receive atezolizumab at fixed dose of 1200 mg IV infusion and bevacizumab at fixed dose of 15 mg/kg IV infusion, every 3 weeks, according to the standard of care. In the experimental arm, these treatments will be combined with the UCPVax vaccine at 0.5 mg subcutaneously.DiscussionCombining anti-PD-1/PD-L1 therapy with an anti-telomerase vaccine gains serious consideration in HCC, in order to extend the clinical efficacy of anti-PD-1/PD-L1. Indeed, anti-cancer vaccines can induce tumor-specific T cell expansion and activation and therefore restore the cancer-immunity cycle in patients lacking pre-existing anti-tumor responses. Thus, there is a strong rational to combine immune checkpoint blockade therapy and anticancer vaccine (UCPVax) in order to activate antitumor T cell immunity and bypass the immunosuppression in the tumor microenvironment in HCC. This pivotal proof of concept study will evaluate the efficacy and safety of the combination of a CD4 Th1-inducer cancer vaccine derived from telomerase (UCPVax) and atezolizumab plus bevacizumab in unresectable HCC, as well as confirming their synergic mechanism, and settling the basis for a new combination for future clinical trials.Trial registrationNCT05528952.

Circulating neutrophil extracellular trap (NET)-forming ‘rogue’ neutrophil subset, immunotype [DEspR + CD11b +], mediate multi-organ failure in COVID-19—an observational study

BackgroundCumulative research show association of neutrophils and neutrophil extracellular traps (NETs) with poor outcomes in severe COVID-19. However, to date, there is no curative intent therapy able to block neutrophil/NETs-mediated progression of multi-organ dysfunction. Because of emerging neutrophil heterogeneity, the study of subsets of circulating NET-forming neutrophils [NET + Ns] as mediators of multi-organ failure progression among patients with COVID-19 is critical to identification of therapeutic targets.MethodsWe conducted a prospective observational study of circulating levels of CD11b + [NET + N] immunotyped for dual endothelin-1/signal peptide receptor (DEspR ±) expression by quantitative immunofluorescence-cytology and causal mediation analysis. In 36 consented adults hospitalized with mod-severe COVID-19, May to September 2020, we measured acute multi-organ failure via SOFA-scores and respiratory failure via SaO2/FiO2 (SF)-ratio at time points t1 (average 5.5 days from ICU/hospital admission) and t2 (the day before ICU-discharge or death), and ICU-free days at day28 (ICUFD). Circulating absolute neutrophil counts (ANC) and [NET + N] subset-specific counts were measured at t1. Spearman correlation and causal mediation analyses were conducted.ResultsSpearman correlation analyses showed correlations of t1-SOFA with t2-SOFA (rho rS = 0.80) and ICUFD (rS = -0.76); circulating DEspR + [NET + Ns] with t1-SOFA (rS = 0.71), t2-SOFA (rS = 0.62), and ICUFD (rS = -0.63), and ANC with t1-SOFA (rS = 0.71), and t2-SOFA (rS = 0.61).Causal mediation analysis identified DEspR + [NET + Ns] as mediator of 44.1% [95% CI:16.5,110.6] of the causal path between t1-SOFA (exposure) and t2-SOFA (outcome), with 46.9% [15.8,124.6] eliminated when DEspR + [NET + Ns] were theoretically reduced to zero. Concordantly, DEspR + [NET + Ns] mediated 47.1% [22.0,72.3%] of the t1-SOFA to ICUFD causal path, with 51.1% [22.8,80.4%] eliminated if DEspR + [NET + Ns] were reduced to zero. In patients with t1-SOFA > 1, the indirect effect of a hypothetical treatment eliminating DEspR + [NET + Ns] projected a reduction of t2-SOFA by 0.98 [0.29,2.06] points and ICUFD by 3.0 [0.85,7.09] days. In contrast, there was no significant mediation of SF-ratio through DEspR + [NET + Ns], and no significant mediation of SOFA-score through ANC.ConclusionsDespite equivalent correlations, DEspR + [NET + Ns], but not ANC, mediated progression of multi-organ failure in acute COVID-19, and its hypothetical reduction is projected to improve ICUFD. These translational findings warrant further studies of DEspR + [NET + Ns] as potential patient-stratifier and actionable therapeutic target for multi-organ failure in COVID-19.

097 VDAC as a novel actionable therapeutic target in pemphigus vulgaris

097 VDAC as a novel actionable therapeutic target in pemphigus vulgaris

Abstract 3406: GATA2 a novel potential therapeutic target for treatment of neuroendocrine prostate cancer

Abstract Neuroendocrine Prostate Cancer (NEPC) is a lethal and aggressive variant of prostate cancer (PC), arises from prostate adenocarcinoma, mainly as a treatment resistant mechanism to Androgen Receptor (AR) signaling inhibitors like enzalutamide. It is independent of AR signaling and characterized by upregulation of neuroendocrine markers like CHGA, SYP, EZH2, MYCN, and CD56. Despite of therapeutic advances, this lethal subtype of PC remains undruggable and has a shorter survival period. Our lab, as well as others, have previously reported several critical functions of GATA2 in AR signaling in PC progression, but the role of GATA2 in NEPC, remained unclear. Here we investigated the role of GATA2 in NEPC using our Patient Derived Xenografts (PDXs), 3D organoid, and 2D cell line models and characterized the pharmacological potency of K-11706, a small molecule inhibitor (SMI) for GATA2 against those NEPC models. To overcome the absence of suitable in vitro models for NEPC, first, we developed 3D organoid and 2D cell line models from NEPC PDX models generated and shared by Dr. Nora Navone at MDACC (mdpc 155-2 and mdpc 144-13). Molecular and histological characterization of these newly developed models showed retention of parent molecular and histological features of their corresponding PDXs. Immunohistochemical characterization of NEPC patient samples and PDXs shows a strong expression of GATA2 protein. Similarly, enzalutamide sensitive cells (16DCRPC cells) showed a significant upregulation of GATA2 mRNA along with neuroendocrine marker genes upon treatment with enzalutamide suggesting upregulation of GATA2 during progression from Castration Resistant Prostate Cancer (CRPC) to NEPC. Pharmacological inhibition of GATA2 by a previously reported SMI, K-11706, efficiently reduced 3D organoid growth and cell viability in vitro, suggesting GATA2 as a potential therapeutic target for NEPC. Gene set enrichment analysis (GSEA) involving our RNA seq data from NEPC cell lines after both K-11706 treatment as well as silencing GATA2 using siRNA (siGATA2) shows a high enrichment score with respect to EZH2 inhibition in curated datasets involving EZH2 inhibition. MTT assay involving a combination of K-11706 and EPZ6438 (EZH2 inhibitor) reduced NEPC cell viability more efficiently than used alone, suggesting a combinational strategy for the treatment of this lethal aggressive PC. NEPC cell line transcriptional profiling and functional pathway analysis of the K-11706 and siGATA2 transcriptomic footprint against curated databases delineated a biological network composed of genes involved in the epithelial mesenchymal transition, hypoxia, genes regulated by NF-kB in response to TNF and KRAS signaling. Based on these results, we propose GATA2 as an actionable therapeutic target for the treatment of NEPC, and pharmacological inhibition of both GATA2 and EZH2 by small molecule inhibitors is effective in NEPC models in vitro. Citation Format: Amit K. Dash, Maria Elisa Ruiz Echartea, Darlene Skapura, Karen Berman de Ruiz, Jenny Jianmin Deng, Cristian Coarfa, Salma Kaochar. GATA2 a novel potential therapeutic target for treatment of neuroendocrine prostate cancer [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 3406.