Refractory Tumors Research Articles

Abstract CT275: Phase 1 clinical update of allogeneic invariant natural killer T cells (iNKTs), agenT-797, alone or in combination with pembrolizumab or nivolumab in patients with advanced solid tumors

Abstract Introduction: AgenT-797 is an allogeneic iNKT cell therapy and represents a novel, scalable, off-the-shelf approach against solid tumors. iNKTs are a unique subset of T cells, that mediate antitumor responses by direct killing, targeting CD1d and other ligands in the tumor microenvironment, and by activating host immune cells. We conducted a clinical trial to investigate agenT-797 activity as single agent and in combination (combo) with PD-1 blockade after prior progression on PD-1 therapy. Methods: Patients (pts) with relapsed or refractory solid tumors were treated with single IV infusion of agenT-797 (no lymphodepletion) at 4.3 × 10^6 or 1.4 × 10^7 cells/kg, as monotherapy or in combo with pembrolizumab (pembro) or nivolumab (nivo). Dose escalation followed 3+3 scheme. Endpoints included safety, persistence of agenT-797, objective responses, duration of response, progression-free survival, and time to response. Adverse events (AEs) were reported per CTCAE v5.0. Dose limiting toxicities (DLTs) were evaluated. AgenT-797 persistence was assessed by assays utilizing SNPs and cfDNA analysis. Serum biomarkers were measured with MSD V-PLEX cytokine assays. On-treatment tumor biopsy was obtained for multiplex immunofluorescence staining and next generation sequencing. Results: As of February 5th, 32 pts (median age 62y, range 30-83) were treated with agenT-797 monotherapy (n=26) or combo (n=6) with pembro or nivo. Pts had median 4 lines of prior therapy (range 1-13). Tumor types included pancreatic (6), NSCLC (4), rectal (4), cholangiocarcinoma/biliary duct (4), and other (14)*. Tolerability was favorable, with no cytokine release syndrome, neurotoxicity, and no DLTs. Treatment-related AEs included 16.7% (5) grade 1, 3.3% (1) grade 2, and 3.3% (1) grade 3 (anemia). At data cutoff, agenT-797 monotherapy and combo revealed early clinical activity. Among 29 evaluable pts, a confirmed partial response in MSI-H gastric cancer refractory to PD-1 treated with agenT-797 + nivo (remains ongoing >6 months) and 8 pts had stable disease (SD). Prolonged SD (>3 months) for 3 monotherapy pts. Overall response rate 20% (1/5) for pts treated with agenT-797 + pembro or nivo. AgenT-797 was detected in peripheral blood up to day 8 post infusion. Preliminary data identified transient increase in serum IFNgamma levels day 2 post infusion. Conclusion: AgenT-797 was well tolerated as monotherapy and in combo with PD-1 (pembro or nivo). Anti-tumor activity in combo with nivo was observed in gastric cancer. Results support the potential of a novel therapeutic strategy employed by agenT-797 to enhance antitumor immunity in PD-1 refractory tumors. Enrollment ongoing and correlative studies will be presented. *PD-1 refractory NSCLC, pancreatic, rectal, cholangiocarcinoma, cervical, gastric, ocular melanoma, renal, and upper tract urothelial Citation Format: Benedito Carneiro, Benjamin Garmezy, John T. Hamm, Rachel E. Sanborn, Trisha Wise-Draper, Anthony El- Khoueiry, Breelyn Wilky, Dave S.B Hoon, Alexa Buffa, Xavier Michelet, Marco Purbhoo, Mark A. Exley, David Einstein. Phase 1 clinical update of allogeneic invariant natural killer T cells (iNKTs), agenT-797, alone or in combination with pembrolizumab or nivolumab in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT275.

Abstract CT255: ELU-FRα-1: a study to evaluate ELU001 in patients with solid tumors that overexpress folate receptor alpha (FRα)

Abstract Background: ELU001 is a novel, first-in-class, new molecular entity described as a C’Dot Drug Conjugate (CDC). ELU001 consists of ~13 folic acid targeting moieties and a payload of ~22 molecules of the topoisomerase-1 inhibitor, exatecan. Folic acid and exatecan are covalently bound by non-cleavable and cathepsin-B cleavable linkers, respectively, to short polyethylene glycol chains which surround the C’Dot’s silica core. CDCs are very small (~6 nm), allowing greater ability to penetrate more efficiently into solid tumors compared to ADCs. CDCs are rapidly eliminated by the kidneys, which is expected to lead to less toxicity than ADCs that have a longer half-life in circulation. ELU001’s high avidity is designed to promote binding to FRα on the surface on FRα overexpressing cancer cells with a wide range of antigen expression including high, moderate and low expressing tumor cells. Following antigen binding, ELU001 internalizes into the tumor cell, and traffics to the lysosome where enzymatic cleavage releases the exatecan payload. The first-in-human trial, ELU-FRα-1, is currently recruiting patients that have advanced, recurrent or refractory tumors associated with indications that are known to potentially overexpress FRα and have been shown to be topoisomerase 1 inhibitor-sensitive, and, in the opinion of the Investigator, have no satisfactory therapeutic options available. Methods: This is a Phase 1/2 multicenter, open label clinical trial with two parts: Part 1 Dose Escalation and Part 2 Tumor Group Expansion Cohort(s). Part 1 is a basket trial enrolling patients with cancer types with a high likelihood of having FRα overexpressing tumors, (specifically, ovarian, endometrial, colorectal, gastric, gastroesophageal junction, triple negative breast, or non-small cell lung cancers, or cholangiocarcinoma). Patients are receiving ELU001 weekly (QW) (once a week for 3 weeks, 1 week rest), every other week (Q2W, with no rest between cycles), or every three weeks (Q3W). Analysis of FRα expression will be retrospectively determined. Part 2 will use Simon’s Two-Stage design to evaluate 4-6 Expansion Cohorts, comprised of tumor histologies anticipated to have greatest activity to ELU001 treatment. FRα will be prospectively determined. The primary objective for Part 1 is to identify the MTD/RP2D. The primary objective for Part 2 is to determine the ORR. Secondary objectives include DOR, PFS, TFST, PFS2, OS, frequency, severity and tolerability of adverse events, PK, ADA, and FRα expression assessments. Part 1 Dose Escalation will recruit about 25 patients per dose regimen (QW; Q2W; Q3W). The first stage of Part 2 (Dose Expansion) will recruit about 15 patients per tumor group expansion cohort. The study is actively enrolling in the US and currently recruiting in Q2W Cohort 201 and Q3W Cohort A. QW Cohorts 1-3 and Q2W Cohort 101 are complete. Clinical trial information: NCT05001282. Citation Format: Wen Wee Ma, Anthony Tolcher, Cesar A. Perez, Douglass Orr, Erika Hamilton, Yujie Zhao, Yonina Murciano-Goroff, Carey Anders, Gregory P. Adams, Catherine W. Reddick, Eliel Bayever. ELU-FRα-1: a study to evaluate ELU001 in patients with solid tumors that overexpress folate receptor alpha (FRα) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT255.

Multi-omic and spatial dissection of immunotherapy response groups in non-small cell lung cancer.

The composition and activation status of the cellular milieu contained within the tumour microenvironment (TME) is becoming increasingly recognized as a driving factor for immunotherapy response. Here, we employed multiplex immunohistochemistry (mIHC), and digital spatial profiling (DSP) to capture the targeted immune proteome and transcriptome of tumour and TME compartments from an immune checkpoint inhibitor (ICI)-treated (n = 41) non-small cell lung cancer (NSCLC) patient cohort. We demonstrate by mIHC that the interaction of CD68+ macrophages with PD1+ , FoxP3+ cells is enriched in ICI refractory tumours (p = 0.012). Patients responsive to ICI therapy expressed higher levels of IL2 receptor alpha (CD25, p = 0.028) within their tumour compartments, which corresponded with increased IL2 mRNA (p = 0.001) within their stroma. In addition, stromal IL2 mRNA levels positively correlated with the expression of pro-apoptotic markers cleaved caspase 9 (p = 2e-5 ) and BAD (p = 5.5e-4 ) and negatively with levels of memory marker, CD45RO (p = 7e-4 ). Immuno-inhibitory markers CTLA-4 (p = 0.021) and IDO-1 (p = 0.023) were suppressed in ICI-responsive patients. Tumour expression of CD44 was depleted in the responsive patients (p = 0.02), while higher stromal expression of one of its ligands, SPP1 (p = 0.008), was observed. Cox survival analysis also indicated tumour CD44 expression was associated with poorer prognosis (hazard ratio [HR] = 1.61, p = 0.01), consistent with its depletion in ICI-responsive patients. Through multi-modal approaches, we have dissected the characteristics of NSCLC immunotherapy treatment groups and provide evidence for the role of several markers including IL2, CD25, CD44 and SPP1 in the efficacy of current generations of ICI therapy.

Abstract 3129: Single-cell RNA sequencing of early-stage to refractory metastatic ER+ breast cancers reveal phenotypic states underlying resistance to multiple lines of therapy

Abstract Breast cancer is a leading cause of global cancer-related mortality. About 75% of breast tumors are estrogen receptor-positive (ER+). Nearly 30-50% of ER+ breast cancers eventually become refractory to multiple lines of therapy and progress to an uncurable metastatic stage despite positive 5-year results on primary endocrine therapy. To uncover the malignant phenotypes underlying the development of therapeutic resistance, we performed single-cell RNA sequencing (scRNA-seq) of 219,532 cells from 80 ER+ breast cancer patients. This included 28 solid tumors and 52 metastatic fluid samples (pleural effusions and ascites). We grouped samples in three groups to study the evolution of biological phenotypes based on the number of lines of therapy administered to a patient: 1. Early (non-metastatic), 2. Advanced (metastatic with less than 3 lines of therapy), and Refractory (metastatic with 3 or more lines of therapy). We used Pareto task inference analysis to model evolutionary task trade-offs across malignant cell populations from the early, advanced, and refractory tumors. Our model revealed 5 unique phenotypic states or “archetypes” that existed across ER+ cancer cells. A multitask learning model based on group lasso revealed the specialized biological tasks associated with each archetype, including 1. Metabolism and self-renewal, 2. EGF/STAT3 signaling, 3. Estrogen signaling, 4. Apoptosis, and 5. MYC activation with rapid proliferation. We found the estrogen signaling archetype was progressively lost in advanced and refractory tumors (P=7.2x10-110), while the MYC archetype was progressively gained in the advanced and refractory tumors (P=2.45x10-9). The EGF/STAT3 archetype was unique to refractory tumors (P= 1.42x10-37). We further investigated the evolution of resistant traits by modeling the pathway phenotypes in malignant cells against the number of lines of therapy received by the patients. Patients refractive to multiple lines of therapy progressively gained mTOR signaling pathway activity concurrent with loss of estrogen-signaling. Multiple pathways that crosstalk with the mTOR pathway were activated in the tumors receiving multiple lines of therapy, including IGFR, and EGF/ERBB signaling. In comparison to early and advanced tumors, refractory tumors also gained JNK/p38 signaling (P=0.006) and activated glycolysis (P=5x10-6). This study reveals how metastatic ER+ breast cancer cells acquire capabilities for resistance to multiple lines of therapy, thus serving as a unique resource for understanding refractory ER+ breast cancer biology. Citation Format: Aritro Nath, Patrick Cosgrove, Jason Griffiths, Jeffrey Chang, Adam Cohen, Andrea Bild. Single-cell RNA sequencing of early-stage to refractory metastatic ER+ breast cancers reveal phenotypic states underlying resistance to multiple lines of therapy [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 3129.

Abstract 4868: Targeting of ERG positive prostate cancers with ERGi-USU-6 salt derivative

Abstract Introduction: Prostate cancer (PCa) is the second leading cause of cancer deaths among men in the United States. Approximately 50% of patients with PCa harbor an oncogenic TMPRRS2- ERG gene fusion in their primary tumor and 35% of patients with metastatic castration resistant prostate cancers have the gene fusion. We have identified a potent small molecule inhibitor, ERGi-USU-6 salt derivative 7b, that selectively inhibits the growth of ERG positive tumor. This small molecule inhibitor is also effective in inhibiting the growth of benign and cancerous mouse prostate organoids expressing TMPRSS2-ERG (ERG positive organoids). To gain insights into the cancer-selective properties of ERGi-USU-6 salt 7b we evaluated pathways associated in ERGi-USU induced inhibition. Methods: The biological activities of salt derivative 7b, were assessed in hormone- refractory metastatic tumor derived ERG positive prostate cancer cell line, VCaP along with organoids. We monitored the pathways associated in the mechanism of drug action through, cell cycle-regulator proteins by immunoblot assays, cell cycle and ferroptosis related analyses in response to 7b treatment. We also monitored the levels of the RIOK2 kinase, previously shown to bind the parental ERGi-USU compound. The normal primary endothelium derived HUVEC cells were used as normal control due to the normal endogenous expression of ERG in endothelial cells including HUVEC. Results: Cell growth and immunoblot analysis indicated the inhibition of ERG positive prostate organoid upon ERGi-USU treatments resulting in the downregulation of ERG and RIOK2 protein levels. The cell cycle analyses, pathway mapping by protein assessment and ferroptotic assays suggests that salt derivative 7b treatment inhibits the ERG positive prostate cancer through ferroptosis along with RIOK2 inhibition. Conclusions: Our results showed that the ferroptosis inducer ATF3 gene is involved in the cancer-selective activity of ERGi-USU-6 salt derivative 7b. Further, based on our observations we hypothesize that ferroptosis, the iron-dependent form of programmed cell-death, may be the mechanism of cancer selective activity of salt derivative 7b. Disclaimer: The contents of this publication are the sole responsibility of the author(s) and do not necessarily reflect the views, opinions or policies of Uniformed Services University of the Health Sciences (USUHS), The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., the Department of Defense (DoD), the Departments of the Army, Navy, or Air Force. Mention of trade names, commercial products, or organizations does not imply endorsement by the U.S. Government. Citation Format: Binil Eldhose, Katherine Beck, Cyrus Eghtedari, Gartrell C. Bowling, Mallesh Pandrala, Sanjay V. Malhotra, Xiaofeng A. Su, Albert Dobi. Targeting of ERG positive prostate cancers with ERGi-USU-6 salt derivative. [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 4868.

Abstract 5745: Proposing the best MET inhibitor to improve anti-PD-1 efficacy in HCC

Abstract Despite recently approved immunotherapy combinations, Hepatocellular carcinoma (HCC) remains among the most therapeutically intractable cancers with a 5-year survival rate of only 18%. Underlying chronic liver disease due to hepatitis B/C infection, alcohol abuse, hemochromatosis, or nonalcoholic steatohepatitis promotes HCC development. Current therapeutic strategies include surgery, radiotherapy and multikinase inhibitors alone or with immune-checkpoint blockade (ICB). In particular, the receptor tyrosine kinase MET and its ligand hepatocyte growth factor (HGF) are known drivers of HCC through promotion of tumor growth, survival, tissue invasion, and angiogenesis. Previously, our collaborators showed that the limited clinical benefit of MET kinase inhibition was partially a result of induced upregulation PD-L1 leading to local T cell suppression. We hypothesized that combining MET inhibition with blockade of the PD-1 immune checkpoint would overcome the limitations of each individual approach and act synergistically to promote HCC tumor regression. We first validated that both MET selective (Capmatinib and Tivantinib) and non-selective (Cabozantinib) inhibitors all induced PD-L1 on HCC cell lines in vitro. Next, we compared Capmatinib and Cabozantinib alone and with PD-1 ICB in vivo in the ICB-sensitive Hepa1-6 and HCA-1 models of HCC. In HCA-1, statistically significant benefit of the MET inhibitor and αPD-1 combination was evident in limitation of tumor growth and extension of survival. In each case, the Capmatinib combination trended toward better outcomes with PD-1 blockade. Mechanistically, the Capmatinib and αPD-1 combination decreased tumor Treg cells while promoting increased accumulation of activated, non-exhausted, proliferating CD8 T cells. Central memory CD8 T cell frequencies were increased by the combination during the effector phase, and combination treated animals were better protected against subsequent rechallenge than those cured by αPD-1 alone. In the myeloid compartment, M1 macrophage frequencies were increased while PMN-MDSC both decreased in frequency and in Arginase 1 levels. Finally, we studied a serially-passaged, αPD-1 refractory DEN HCC model. Despite lack of efficacy of either component therapy, the MET inhibitor and αPD-1 combination significantly extended survival and inhibited tumor growth. As in the αPD-1 sensitive setting, Capmatinib appeared to offer the most therapeutic benefit with αPD-1. Ongoing studies are focused on characterizing changes mediated by the combination therapy which confer aPD-1 sensitivity to the otherwise refractory DEN HCC tumor microenvironment. Molecular studies are focused on understanding the superior ICB potentiating capacity of Type I MET inhibitors versus the other classes. Given the clinical availability of numerous MET and PDL-1 inhibitors, we hope to inform near-term optimization of MET and αPD-1 clinical trial design for HCC. Citation Format: Ricardo A. de Azevedo, Broderick Turner, Priyamvada Jayaprakash, Krithikaa Rajkumar Bhanu, Anupallavi Srinivasamani, Brittany Morrow, Michelle Winkler, Shweta Mahendra Hedge, Arthur Liu, Ravaen Slay, Michael A. Curran. Proposing the best MET inhibitor to improve anti-PD-1 efficacy in HCC. [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 5745.

Abstract 1801: STK-012, an a/b-selective IL-2 activates tumor antigen specific CD25+ CD8 T cells to reject tumors without acute vascular toxicity

Abstract High-dose Interleukin-2 (IL-2) monotherapy induces complete responses in cancer patients but its use is limited by acute vascular toxicities including capillary leak syndrome and severe hypotension 1,2. IL-2 activates lymphocytes and NK-cells through the intermediate-affinity dimeric IL-2 receptor, IL-2Rβ/γ (CD122/CD132), while antigen activated T-cells and regulatory T-cells (Tregs) have increased sensitivity to IL-2 by expressing the high-affinity trimeric IL-2 receptor, IL-2Rα/β/γ (CD25/CD122/CD132)3. CD25-independent IL-2s (“non-α-IL-2s”) aim to increase the therapeutic efficacy of IL2 in cancer patients by avoiding Treg activation through selective binding to IL-2Rβ/γ 4. However, those molecules still are reported to induce fever and hypotension and have limited efficacy as a monotherapy or in combination with anti-PD-1 5,6. Here we show that a novel α/β-IL-2 agonist that was designed to preferentially bind to the IL-2Rα/β/γ receptor highly upregulated on antigen activated T-cells can greatly improve on the efficacy of IL-2 while avoiding the vascular toxicity commonly associated with IL-2 treatment. In syngeneic tumor models, this α/β-IL-2 agonist significantly reduced exhaustion of tumor infiltrating T cells compared to WT-IL-2 or a non-α-IL-2 leading to improved expansion of tumor antigen specific CD25+PD-1+CD8+ T cells systemically and in the tumor microenvironment. This resulted in complete responses and tumor immune memory with α/β-IL-2 monotherapy as well as improved outcomes in combination with anti-PD-1 therapy in PD-1 refractory syngeneic tumors. In contrast, WT-IL-2 reduced T cell exhaustion and drove antigen specific T cell responses to a lesser degree, resulting in reduced combinatorial efficacy with anti-PD-1, while the non-α-IL-2 failed to do either. Furthermore, the α/β-IL-2 agonist reduced intratumoral Tregs compared to treatment with WT-IL-2 or PBS improving the intratumoral CD8 to Treg ratio. In non-human primates and mice, WT-IL-2 and a non-α-IL-2 led to broad extravasation of lymphocytes and NK cells and activation of intra-pulmonal T cells resulting in systemic tissue inflammation and NK cell-mediated lethal capillary leak syndrome whereas the α/β-IL-2 agonist, which avoids binding the dimeric IL-2Rβ/γ expressed on NK cells, avoided systemic lymphocyte activation which facilitated continuous treatment without acute vascular toxicities. Overall, through selective engagement of CD25+ T cells, this α/β-IL-2 agonist demonstrated improved efficacy and tolerability of IL-2 in preclinical tumor models. Clinical trials with STK-012, a human α/β-IL-2 agonist, are in progress.1 Atkins, et al.; JCO 1999, 2 Dutcher, et al.; JITC 2014, 3 Liao, et al.; Immunity 2013, 4 Levin, et al.; Nature 2012, 5 Janku, et al.; Cancer Research 2021; 6 Diab, et al.; Cancer Disc. 2020 Citation Format: Martin Oft, Navneet Ratti, Sandro Vivona, Jan Emmerich, Romina Riener, Ievgen O. Koliesnik, Scott McCauley, Michele Bauer, Marie Semana, Deepti Rokkam, Bhargavi Jayaraman, Rene de Waal Malefyt, Paul-Joseph Aspuria, Michael Totagrande, Anita Mehta-Damani, Patrick J. Lupardus, Rob A. Kastelein. STK-012, an a/b-selective IL-2 activates tumor antigen specific CD25+ CD8 T cells to reject tumors without acute vascular toxicity [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 1801.

Abstract 487: ITI-1020, a novel PDE type 1 inhibitor, reduces tumor growth in triple negative breast cancer (TNBC) mouse models

Abstract Breast cancer is the most common cancer in women. Unfortunately, some patients do not benefit from most therapies and may even develop resistance to previously effective treatments leading to disease progression. Therefore, treatment resistance remains a significant challenge and new treatments are needed to overcome this problem. ITI-1020 is a potent and highly selective inhibitor of the phosphodiesterase 1 (PDE1) enzyme. Given the role of PDE1 in the regulation of essential cellular functions, including among others the transition of monocytes to macrophages and potentially the infiltration of macrophages into the tumor microenvironment (TME), we hypothesize that ITI-1020 will alter macrophage infiltration and polarization, as well as improve T cell function and recruitment into the TME, thereby promoting antitumor immunity in murine cancer models. We tested this hypothesis by studying the effect of ITI-1020 given, alone or in combination a PD-1 immune checkpoint inhibitor, on tumor growth, and TME composition of E0771 and 4T1 tumor-bearing mice, two syngeneic models of TNBC. Mice treated with ITI-1020 alone or in combination with anti-PD-1 antibody showed significant inhibition of tumor growth compared to isotype controls in both type of tumors. Flow cytometry analysis of the tumor microenvironment showed a significant shift in the polarization of macrophages toward a more inflammatory phenotype, and/or a reduction in the number of exhausted T cells. Furthermore, scRNAseq analysis of tumors from mice treated with ITI-1020 in monotherapy showed altered expression of genes involved in inflammatory processes and cell proliferation within the tumor microenvironment and in the cancer cells. These results suggest that ITI-1020 promotes antitumor immunity by a novel mechanism (PDE1 inhibition), leading to tumor growth inhibition in E0771 and 4T1 tumor models. Translating these findings to the clinic may provide a new hope for the treatment of refractory or resistant TNBC tumors. Citation Format: Maud Voisin, Aksinija A. Kogan, Stephen Goding, Gretchen L. Snyder, Robert E. Davis. ITI-1020, a novel PDE type 1 inhibitor, reduces tumor growth in triple negative breast cancer (TNBC) mouse models [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 487.

Abstract 4832: Copy number amplification of OXPHOS genes drives tumor hypoxia in NSCLC

Abstract Non-small cell lung cancer (NSCLC) is a highly aggressive disease with a dismal prognosis associated with high rates of treatment resistance and disease recurrence. High-dose stereotactic body radiation therapy (SBRT) is the standard of care for locally advanced non-resectable NSCLC. However, as discovered more than six decades ago, tumor hypoxia is a significant barrier to effective radiation therapy. In the last decade, immunotherapy targeting immune checkpoints such as programmed cell death 1 (PD-1) has been introduced as first-line NSCLC treatment, yet long-term disease control occurs in less than 25% of patients. Therefore, understanding the mechanisms of the treatment resistance is essential to address the need for novel synergistic therapies to sensitize refractory NSCLC tumors to anti-cancer treatment. Tumor hypoxia has been associated with treatment resistance for decades, yet its role in the clinical management of NSCLC remains largely unexplored. The basis of tumor hypoxia has traditionally been attributed to the oxygen supply deficit as malformed tumor vasculature fails to meet the high demand of the rapidly proliferating tumor mass. However, our preliminary analysis of NSCLC patient datasets in the Cancer Genome Atlas (TCGA) revealed a significant correlation between high-level expression of nuclear genes encoding mitochondrial subunits essential for oxidative phosphorylation (OXPHOS) and the expression of validated hypoxia-regulated genes (Buffa hypoxia score). The oxygen-consumption expression signature was implemented in software that enables the calculation of numerous tumor microenvironment expression signatures, called tmesig. Furthermore, we have observed a direct positive correlation between the hypoxia expression signatures levels in NSCLC patient samples and the copy number amplification (CNA) of essential OXPHOS genes. Because mitochondrial function consumes up to 90% of available cellular oxygen, its activity may indirectly regulate oxygen availability in the tumor microenvironment by rapidly consuming oxygen upon its delivery to the tumor. Mechanistically, this leads to the hypothesis that OXPHOS gene amplification drives mitochondrial function, which may, in turn, promote tumor hypoxia and treatment resistance in NSCLC. Citation Format: Martin Benej, Katarina Benejova, McKenzie Kreamer, Jinghai Wu, Syed Ashraf, Caroline Wheeler, Rebecca Hoyd, Daniel Spakowicz, Nicholas C. Denko. Copy number amplification of OXPHOS genes drives tumor hypoxia in NSCLC. [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 4832.

Abstract 6570: Integrative pan-cancer genomic and transcriptomic analyses of refractory metastatic cancer

Abstract Metastatic relapse after treatment is the primary cause of cancer morbidity and mortality. While genetic mechanisms of primary tumors and, to a lesser extent, metastatic cancers have been studied in large cohorts, refractory metastatic tumors are not yet sufficiently characterized. Markers of aggressiveness and resistance that molecular profiling can extract from these tumors have yet to be identified and incorporated into clinical care. In this study, we present a pan-cancer cohort of 1,031 metastatic tumors (which we refer to as META-PRISM) that are resistant to at least one systemic therapy or with no approved treatment options. We retrieved the complete clinical history of patients and performed whole-exome (n=571) and transcriptome sequencing (n=947) for this cohort. The prevalence of detected cancer biomarkers was assessed and compared to an external cohort of primary tumors. In the META-PRISM cohort, we observed an increase in (i) whole-genome duplication frequency, (ii) tumor mutational burden, (iii) germline cancer-predisposing variants, and (iv) somatic alterations in cancer genes, including KRAS, EGFR, CCND1, MYC, and TP53, as compared to the tumor type-matched primary tumors. The most extensive increase in genomic variation at metastatic stage was observed in prostate bladder, and pancreatic cancer types. We also identified enrichment of standard-of-care resistance biomarkers in most cancer types. However, only 9.3% of tumors harbored at least one such biomarker, indicating that the current understanding of resistance mechanisms remains insufficient. Our cohort demonstrated a significantly improved 6-month survival prediction from models incorporating molecular markers over models with only clinical markers for breast cancer patients and to a lesser extent for other studied tumor types. Overall, our data establish a unique resource for investigating treatment resistance mechanisms and performing predictive analyses in cancer. Citation Format: Yoann Pradat, Julien Viot, Konstantin Gunbin, Andrey Yurchenko, Luigi Cerbone, Marc Deloger, Guillaume Grisay, Loic Verlingue, Véronique Scott, Ismael Padioleau, Leonardo Panunzi, Stefan Michiels, Antoine Hollebecque, Gerome Jules-Clément, Laura Mezquita, Antoine Lainé, Yohann Loriot, Benjamin Besse, Luc Friboulet, Fabrice André, Paul-Henry Cournède, Daniel Gautheret, Sergey Nikolaev. Integrative pan-cancer genomic and transcriptomic analyses of refractory metastatic 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 6570.

Abstract 4878: Transcriptional response to rocaglate translation inhibitors in lymphoma shows cellular adaptation through induction of stress and survival pathways

Abstract Background: 40% of diffuse large B-cell lymphoma (DLBCL) patients do not achieve cure in response to the standard immunochemotherapy. Relapsed and refractory tumors respond poorly to targeted signaling inhibitors due to pathway redundancies in this genetically heterogenous disease. Pharmacologic disruption of the cap-initiation complex eIF4F is an emerging clinical treatment strategy to bypass resistance. In preclinical experiments, B-lymphomas show high susceptibility to rocaglates, natural and synthetic cap-dependent translation inhibitors. Among these compounds, eFT226 (zotatifin), is currently in phase I/II clinical evaluation for solid tumors. Rocaglate mechanisms remain incompletely defined for use in B-cell lymphoma. Recent findings in our laboratory revealed translationally mediated adaptation that increased synthesis of many targets. Proteins (i.e.CD98hc) that paradoxically increase in production contribute to persistence of cells that survive treatment. By contrast, transcriptional responses to rocaglates remain minimally studied. Here we sought to fill this gap through unbiased transcriptomics. Method: RNA sequencing (RNA-seq) was performed on zotatifin treated DLBCL cells (SU-DHL10) vs DMSO controls. Genes with a false discovery rate p-value (FDR) ≤0.05, logarithm of counts per million reads (logCPM) ≥ 0 and P value ≤0.05 were considered differentially expressed. Log2 fold change (FC) ≥ +/-2-fold for a specific gene was considered significantly differentially expressed between the two groups. Pathway analysis was performed using Gene Set Enrichment Analysis (GSEA). Results: We found 4450 differentially expressed genes, 12 significantly upregulated, and 42 significantly downregulated in response to zotatifin (FC ≥ 2). Further pathways analyses showed 4/25 gene sets significantly upregulated, and 3/22 gene sets significantly downregulated (FDR <0.25). We found significantly upregulated genes related to mechanisms stress and survival pathways including NF-kB induction by TNF signaling (normalized enriched score (NES)=2.28; p-value <0.0001), genes induced in response to hypoxia translational stress responses (NES=1.85; nominal p-value=0.008). Conclusions: These results implicate induction of specific survival pathways that induce transcriptionally mediated adaptation to the stress of rocaglate therapy, but it is unclear if these responses can result in altered protein production in the context of eIF4A inhibition. Parallel assessment of the translatome currently under analysis will provide a more complete picture of overall adaptation and provide rational combination targets for rocaglates in lymphoma as clinical development progresses. Citation Format: Paola Manara, Tyler Andrew Cunningham, Jr Jyun David Ho, Olivia B. Lightfuss, Abdessamad Youssfi Alaoui, Jonathan Harry Schatz. Transcriptional response to rocaglate translation inhibitors in lymphoma shows cellular adaptation through induction of stress and survival pathways. [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 4878.

Abstract 2771: KSQ-4279 mediated USP1 inhibition induces replication associated DNA gaps that contribute to cell death

Abstract Tumors with defects in DNA double strand break (DSB) repair pathways, including those with mutations in BRCA1/2, are often treated with either poly (ADP-ribose) polymerase-1 (PARP1) inhibitors or platinum-based chemotherapy. Despite their clinical benefits, many patients develop resistance leading to the need for novel therapeutic approaches. To address this unmet clinical need, we applied our CRISPRomics® platform to identify novel therapeutic targets for DNA damage and repair deficient cancers. One of the top ranked targets was the deubiquitinating enzyme, USP1, with known functions in DNA damage repair pathways of translesion synthesis (TLS) and fanconi anemia (FA). We developed a novel small molecule inhibitor, KSQ-4279, that selectively inhibits USP1 and leads to accumulation of mono-ubiquitinated USP1 substrates such as proliferating nuclear antigen (PCNA). In addition to KSQ-4279’s activity in BRCA mutant tumors with known homologous recombination deficiencies (HRD), KSQ-4279 also exhibits synergistic activity in combination with PARP inhibitors and re-sensitizes PARP refractory tumors. Mechanistically, we show that in sensitive cell lines, treatment with KSQ-4279 alters the replication fork dynamics resulting in replication stress via induction of replication associated single stranded DNA gaps and subsequent fork degradation. Additionally, KSQ-4279 leads to loss of the essential DNA replication and repair protein, PCNA, which can be rescued by blocking PCNA ubiquitination either through Rad18 knockout or by ectopic expression of a PCNA K164R mutant. This loss of PCNA and sensitizing ssDNA lesions eventually lead to DNA double strand breaks (DSBs) and wide-spread DNA damage accumulation that contributes to cell death. This mechanistic insight supports the ongoing clinical trial of KSQ-4279 in patients with tumors harboring BRCA1/2 or other HRD mutations, both as a single agent and in combination with PARP inhibitors. Citation Format: Sumeet Nayak, Pamela Sullivan, Yuji Mishina, Anne Dodson, Pei-Lun Kao, Hugh Gannon, Chris Middleton, Sol Shenker, Morgan Murray, Michael Schlabach, Frank Stegmeier, Erica Tobin, Louise Cadzow, Andrew Wylie. KSQ-4279 mediated USP1 inhibition induces replication associated DNA gaps that contribute to cell death [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 2771.

MP53-01 TOXICITY OF CYTOREDUCTIVE SURGERY AND HYPERTHERMIC INTRAPERITONEAL CHEMOTHERAPY (HIPEC) IN PEDIATRIC PATIENTS WITH RHABDOMYOSARCOMA: EARLY EXPERIENCE AND RESULTS OF A PHASE 1 TRIAL

You have accessJournal of UrologyCME1 Apr 2023MP53-01 TOXICITY OF CYTOREDUCTIVE SURGERY AND HYPERTHERMIC INTRAPERITONEAL CHEMOTHERAPY (HIPEC) IN PEDIATRIC PATIENTS WITH RHABDOMYOSARCOMA: EARLY EXPERIENCE AND RESULTS OF A PHASE 1 TRIAL Andres Guillen Lozoya, Alexander Krueger, Candace Granberg, and Patricio Gargollo Andres Guillen LozoyaAndres Guillen Lozoya More articles by this author , Alexander KruegerAlexander Krueger More articles by this author , Candace GranbergCandace Granberg More articles by this author , and Patricio GargolloPatricio Gargollo More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003301.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Soft-tissue sarcomas as a group comprise the most common type of extra-cranial solid tumor type in children. Most soft-tissue sarcomas diagnosed in children are rhabdomyosarcoma (RMS). Rapid growth and aggressive metastatic spread are major factors in severely decreasing the prognosis of patients with this condition, and current therapies for recurrence of intraperitoneal malignancies have not provided an increase in survival over several decades. HIPEC has been demonstrated to improve survival in several adult peritoneal malignancies. Similarly, in children cytoreduction and HIPEC have been applied to some pediatric malignancies with promising results. We aim to evaluate toxicities of pediatric RMS patients treated with continuous perfusion of hyperthermic intraperitoneal cisplatin+doxorubicin. METHODS: This is a single-arm feasibility and safety study. Pediatric patients with resectable primary refractory or recurrent intra-abdominal RMS tumors treated with HIPEC (CIS+DOXO) from June of 2019 to June of 2022 were included in the analysis. Patients with mets not limited to peritoneum, prior HIPEC, active infection or systemic illness were excluded from the study. Clinical and demographic variables, adverse events within 30 days post-Op, recurrence free survival (RFS) and overall survival (OS) were compiled and stratified. RESULTS: A total of n=6 participants were included in the analysis. The cohort was comprised mostly of female patients (83%), Bladder was the most common primary tumor location (50%) and Embryonal was the most common subtype (83%). Median OS of the cohort was 20.4±6.6 months, non-deceased patients have had a median survival of 36±7.5 months and mean RFS of 14 months. 50% of the cohort evolve without a grade ≥3 adverse event [CTCAE v4]. Table 1 CONCLUSIONS: We conclude that the study technique is reasonably well tolerated in pediatric patients with refractory or recurrent intra-abdominal RMS tumors. The efficacy of Cytoreductive Surgery and HIPEC in pediatric RMS patients needs further evaluation with a larger cohort of patients. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e712 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Andres Guillen Lozoya More articles by this author Alexander Krueger More articles by this author Candace Granberg More articles by this author Patricio Gargollo More articles by this author Expand All Advertisement PDF downloadLoading ...

Multimodal immunogenomic biomarker analysis of tumors from pediatric patients enrolled to a phase 1-2 study of single-agent atezolizumab

We report herein an exploratory biomarker analysis of refractory tumors collected from pediatric patients before atezolizumab therapy (iMATRIX-atezolizumab, NCT02541604). Elevated levels of CD8+ T cells and PD-L1 were associated with progression-free survival and a diverse baseline infiltrating T-cell receptor repertoire was prognostic. Differential gene expression analysis revealed elevated expression of CALCA (preprocalcitonin) and CCDC183 (highly expressed in testes) in patients who experienced clinical activity, suggesting that tumor neoantigens from these genes may contribute to immune response. In patients who experienced partial response or stable disease, elevated Igα2 expression correlated with T- and B-cell infiltration, suggesting that tertiary lymphoid structures existed in these patients’ tumors. Consensus gene co-expression network analysis identified core cellular pathways that may play a role in antitumor immunity. Our study uncovers features associated with response to immune-checkpoint inhibition in pediatric patients with cancer and provides biological and translational insights to guide prospective biomarker profiling in future clinical trials.

Nanosecond Pulsed Electric Field Induces an Antitumor Effect in Triple-Negative Breast Cancer via CXCL9 Axis Dependence in Mice

Triple-negative breast cancer (TNBC) is a refractory tumor, and therapeutic options are very limited. Local ablation has been applied recently. Chemokines play a critical role in the recruitment of immune cells into ablative tumors. Nanosecond pulsed electric field (nsPEF) shows potential anti-tumor efficacy, but the mechanism for maintaining the immune effect is not very clear. Here, we applied nsPEF for treating 4T1 breast cancer cells in vitro. RNA sequencing (RNA-seq) was applied. Anti-CXCL9 was used alone or combined with nsPEF to treat triple-negative breast cancer in mice. We demonstrated that nsPEF effectively induced cell apoptosis and inhibited the growth and metastasis of triple-negative breast cancer. An immune effect, especially chemotaxis, was activated by nsPEF. The number of infiltrated CD8+ T cells was increased significantly. We found that the inhibition of residual breast cancer growth by nsPEF was dependent on the CXCL9 axis. In conclusion, our work demonstrated that nsPEF effectively ablated the tumor, aroused an immune response, and inhibited residual breast cancer growth via CXCL9 axis dependence in mice.

Epothilones as Natural Compounds for Novel Anticancer Drugs Development.

Epothilone is a natural 16-membered macrolide cytotoxic compound produced by the metabolism of the cellulose-degrading myxobacterium Sorangium cellulosum. This review summarizes results in the study of epothilones against cancer with preclinical results and clinical studies from 2010-2022. Epothilone have mechanisms of action similar to paclitaxel by inducing tubulin polymerization and apoptosis with low susceptibility to tumor resistance mechanisms. It is active against refractory tumors, being superior to paclitaxel in many respects. Since the discovery of epothilones, several derivatives have been synthesized, and most of them have failed in Phases II and III in clinical trials; however, ixabepilone and utidelone are currently used in clinical practice. There is robust evidence that triple-negative breast cancer (TNBC) treatment improves using ixabepilone plus capecitabine or utidelone in combination with capecitabine. In recent years innovative synthetic strategies resulted in the synthesis of new epothilone derivatives with improved activity against refractory tumors with better activities when compared to ixabepilone or taxol. These compounds together with specific delivery mechanisms could be developed in anti-cancer drugs.

Advantages and Disadvantages of Car-T Therapy in the Clinical Treatment of Diffuse Large B-Cell Lymphoma (DLBCL)

Chimeric antigen receptor T-cell (CAR-T) therapy is a new innovative cancer treatment. In recent years, many clinical studies have demonstrated its efficacy in the treatment of DLBCL. Compared to many existing cancer treatments, CAR-T therapy offers many advantages. For example, unique specificity and excellent efficacy in patients with refractory and recurrent tumors. This article focuses on the application of CAR-T in the treatment of DLBCL and analyzes the advantages and disadvantages of this therapy from multiple perspectives. The advantages of CAR-T therapy are discussed in three aspects: CAR-T for relapsed and chemotherapy-resistant patients, CAR-T cell’s distinctive specificity and ideal treatment outcome. Then, the three most representative limitations of CAR-T therapy are analyzed in this article: antigen escape, antigen-positive relapse, and toxicities. Finally, the article points out the promising future of CAR-T therapy.

A drug repurposing approach for individualized cancer therapy based on transcriptome sequencing and virtual drug screening

RNA-sequencing has been proposed as a valuable technique to develop individualized therapy concepts for cancer patients based on their tumor-specific mutational profiles. Here, we aimed to identify drugs and inhibitors in an individualized therapy-based drug repurposing approach focusing on missense mutations for 35 biopsies of cancer patients. The missense mutations belonged to 9 categories (ABC transporter, apoptosis, angiogenesis, cell cycle, DNA damage, kinase, protease, transcription factor, tumor suppressor). The highest percentages of missense mutations were observed in transcription factor genes. The mutational profiles of all 35 tumors were subjected to hierarchical heatmap clustering. All 7 leukemia biopsies clustered together and were separated from solid tumors. Based on these individual mutation profiles, two strategies for the identification of possible drug candidates were applied: Firstly, virtual screening of FDA-approved drugs based on the protein structures carrying particular missense mutations. Secondly, we mined the Drug Gene Interaction (DGI) database (https://www.dgidb.org/) to identify approved or experimental inhibitors for missense mutated proteins in our dataset of 35 tumors. In conclusion, our approach based on virtual drug screening of FDA-approved drugs and DGI-based inhibitor selection may provide new, individual treatment options for patients with otherwise refractory tumors that do not respond anymore to standard chemotherapy.

Total steroidal saponins from black nightshade (Solanum nigrum L.) overcome tumor multidrug resistance by inducing autophagy-mediated cell death in vivo and in vitro.

Multiple drug resistance (MDR) often occurs after prolonged chemotherapy, leading to refractory tumors and cancer recurrence. In this study, we demonstrated that the total steroidal saponins from Solanum nigrum L. (SN) had broad-spectrum cytotoxic activity against various human leukemia cancer cell lines, especially in adriamycin (ADR)-sensitive and resistant K562 cell lines. Moreover, SN could effectively inhibit the expression of ABC transporter in K562/ADR cells in vivo and in vitro. In vivo, by establishing K562/ADR xenograft tumor model, we demonstrated that SN might overcome drug resistance and inhibit the proliferation of tumors by regulating autophagy. In vitro, the increased LC3 puncta, the expression of LC3-II and Beclin-1, and the decreased expression of p62/SQSTM1 in SN-treated K562/ADR and K562 cells demonstrated autophagy induced by SN. Moreover, using the autophagy inhibitors or transfecting the ATG5 shRNA, we confirmed that autophagy induced by SN was a key factor in overcoming MDR thereby promoting cell death in K562/ADR cells. More importantly, SN-induced autophagy through the mTOR signaling pathway to overcome drug resistance and ultimately induced autophagy-mediated cell death in K562/ADR cells. Taken together, our findings suggest that SN has the potential to treat multidrug-resistant leukemia.

Exploring the role of the tumor microenvironment in refractory pituitary tumor pathogenesis.

Treatment-refractory pituitary tumors demonstrate characteristics resembling those of highly aggressive tumors, in which the local tumor microenvironment (TME) plays a dominant role in promoting aggressiveness and refractoriness. However, role of the TME in pituitary tumors is not well studied. Literature on the TME and development of refractory pituitary tumors was reviewed RESULTS: TME harbors tumorigenic immune cells, cancer-associated fibroblasts (CAF), extracellular matrix, and other factors that have been shown to affect behavior of tumor tissue. For example, tumor-associated macrophages and tumor-infiltrating lymphocytes correlate with aggressive and invasive tumor behavior in nonfunctioning and growth hormone-secreting (GH) pituitary tumors, while CAF release of TGFβ, FGF2, cytokines, chemokines, and growth factors may promote treatment resistance, tumor fibrosis, and inflammation in prolactinomas and GH-secreting tumors. In turn, Wnt pathway activation can further promote cell growth in dopamine-resistant prolactinomas. Finally, proteins secreted by extracellular matrix are associated with increased angiogenesis in invasive tumors. It is likely that multiple mechanisms, including TME, contribute to the development of aggressive refractory pituitary tumors. Given the increased morbidity and mortality associated with pituitary tumor refractoriness, more research on the role of TME is warranted.