Support Tumor Growth Research Articles

Osteocytes: New Kids on the Block for Cancer in Bone Therapy.

The tumor microenvironment plays a central role in the onset and progression of cancer in the bone. Cancer cells, either from tumors originating in the bone or from metastatic cancer cells from other body systems, are located in specialized niches where they interact with different cells of the bone marrow. These interactions transform the bone into an ideal niche for cancer cell migration, proliferation, and survival and cause an imbalance in bone homeostasis that severely affects the integrity of the skeleton. During the last decade, preclinical studies have identified new cellular mechanisms responsible for the dependency between cancer cells and bone cells. In this review, we focus on osteocytes, long-lived cells residing in the mineral matrix that have recently been identified as key players in the spread of cancer in bone. We highlight the most recent discoveries on how osteocytes support tumor growth and promote bone disease. Additionally, we discuss how the reciprocal crosstalk between osteocytes and cancer cells provides the opportunity to develop new therapeutic strategies to treat cancer in the bone.

Abstract IA14: Host autophagy mediates organ wasting and nutrient mobilization for tumor growth

Abstract During tumor growth-when nutrient and anabolic demands are high-autophagy supports tumor metabolism and growth through lysosomal organelle turnover and nutrient recycling. Ras-driven tumors additionally invoke non-autonomous autophagy in the microenvironment to support tumor growth, in part through transfer of amino acids. Here we uncover a third critical role of autophagy in mediating systemic organ wasting and nutrient mobilization for tumor growth using a well-characterized malignant tumor model in Drosophila melanogaster. Micro-computed X-ray tomography and metabolic profiling reveal that RasV12 ; scrib-/- tumors grow 10-fold in volume, while systemic organ wasting unfolds with progressive muscle atrophy, loss of body mass, -motility, -feeding, and eventually death. Tissue wasting is found to be mediated by autophagy and results in host mobilization of amino acids and sugars into circulation. Natural abundance Carbon 13 tracing demonstrates that tumor biomass is increasingly derived from host tissues as a nutrient source as wasting progresses. Thus, host autophagy mediates organ wasting and nutrient mobilization that is utilized for tumor growth. Citation Format: Petter Holland, Todd Andrew Schoborg, Ifat Abramovich, Szabolcs Takáts, Caroline Dillard, Ashish Jain, Fergal O'Farrell, Sebastian Wolfgang Schultz, William M. Hagopian, Eduardo Martin Quintana, Rachel Ng, Nadja Sandra Katheder, Mohammed Mahidur Rahman, José Gerardo Teles Reis, Andreas Brech, Heinrich Jasper, Nasser M. Rusan, Anne Hope Jahren, Eyal Gottlieb, Tor Erik Rusten. Host autophagy mediates organ wasting and nutrient mobilization for tumor growth [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr IA14.

Characterizing the role of IL-33/ST2 axis in regulating anti-tumor function by CD8 T cells during tumor metastasis in the omentum.

Abstract The omentum, a visceral adipose tissue, is a frequent site of metastasis for gastric and ovarian cancers. Advanced ovarian cancer almost always metastasizes to the omentum. Currently available therapies do not control tumor growth long-term and there is a frequent recurrence of tumor metastasis. In mice, tumor cells injected intraperitoneally implant in the omentum and grow progressively despite tumor-specific CD8 T cells. The lack of effective immunity is due in part, to rapid Treg recruitment in the omentum, which provides an immunosuppressive environment to support tumor growth. The Tregs in the omentum are a specialized population called visceral adipose tissue associated Tregs (VAT-Tregs). A portion of the omental VAT-associated Tregs express ST2, a receptor for Interleukin-33 (IL-33), suggesting that local IL-33 production may contribute to Treg-mediated suppression in the omentum. We also detected persistent, continuously expanding, tumor-specific CD8 T cells in the omentum. Given that IL-33 can also enhance effector function by CD8 T cells and promote their persistence in the presence of chronic antigen stimulation, we are investigating how IL-33 regulates the balance of Treg-mediated immune-suppression and CD8-mediated tumor cell killing in the context of omental adipose tissue. R01CA216234

N6-Methyladenosine Promotes Translation of VEGFA to Accelerate Angiogenesis in Lung Cancer.

Methylation of the 5'UTR IRES of VEGFA mRNA increases cap-independent translation via recruitment of the YTHDC2/eIF4GI complex, which stimulates angiogenesis to promote lung tumor growth.

Impact of context-dependent autophagy states on tumor progression.

Macroautophagy is a cellular quality-control process that degrades proteins, protein aggregates and damaged organelles. Autophagy plays a fundamental role in cancer where, in the presence of stressors (for example, nutrient starvation, hypoxia, mechanical pressure), tumor cells activate it to degrade intracellular substrates and provide energy. Cell-autonomous autophagy in tumor cells and cell-nonautonomous autophagy in the tumor microenvironment and in the host converge on mechanisms that modulate metabolic fitness, DNA integrity and immune escape and, consequently, support tumor growth. In this Review, we will discuss insights into the tumor-modulating roles of autophagy in different contexts and reflect on how future studies using physiological culture systems may help to understand the complexity and open new therapeutic avenues.

Abstract LB027: In vivo delivery of novel CD89 fusion receptor to myeloid cells by mRNA activates anti-tumor immunity

Abstract Despite the revolution provided by immunotherapy, sustained clinical benefit has yet to be achieved for most of patients with advanced solid tumors. Myeloid cells readily accumulate in tumors, in some cases contributing up to 75% of the tumor mass. While supporting tumor growth and being associated with unfavorable prognosis, myeloid cells can mediate phagocytosis of cancer cells and cytotoxic tumor killing and promote adaptive immune responses through antigen presentation and co-stimulation, therefore representing promising targets in cancer therapy. The ability to engineer circulating and tumor associated myeloid cells to activate their ability to elicit anti-tumor adaptive immunity is an attractive approach to harness systemic anti-tumor immunity. However, it remains challenging to specifically target and activate myeloid cells in vivo. To overcome this hurdle, we have developed a novel in vivo myeloid cell engineering platform in which a chimeric antigen receptor (CAR) is generated by fusing a tumor recognition scFv with the alpha chain of human Fc receptors (CD89). The stable expression and function of these receptors requires the endogenously expressed common Fc receptor gamma chain (FcRγ), which expression is mostly restricted to myeloid cells. For in vivo engineering, the construct is encapsulated and delivered in lipid nanoparticles (LNP). Trophoblast cell surface antigen 2 (TROP2) is overexpressed in most human solid epithelial cancers, as compared to low expression in corresponding normal tissue. Increased TROP2 expression has been linked to increased tumor growth and has been implicated as a prognostic marker in these cancers, supporting the development of therapies targeting TROP2. Intravenous infusion of LNP encapsulating mRNA encoding the anti-TROP2-CD89 fusion protein results in the uptake of the LNPs and expression of the chimeric receptor fusion protein in myeloid cells. In immunodeficient xenograft models of hepatocellular carcinoma and triple negative breast cancer, delivery of LNP mRNA encoding GPC3-CD89 or TROP2-CD89 fusion proteins resulted in anti-tumor efficacy, confirming the ability of this approach to program myeloid cells. Repeat dosing studies showed significant anti-tumor efficacy following bi-weekly administration of TROP2-CD89. Furthermore, in the B16/10 syngeneic melanoma model, treatment with the melanoma antigen gp75-CD89 fusion protein was also associated with the initiation of broad systemic immune responses, characterized by tumor infiltration by activated CD8+ T cells, reduced tumor-associated Tregs and activation of antigen presenting cells in spleen. When infused in cynomolgus monkeys, TROP2-CD89 LNP led to cell surface expression of anti-TROP2 CAR in myeloid cells. Together these studies highlight the potential of in vivo delivery of CD89 fusion proteins to program myeloid cells to recognize and kill cancer. Citation Format: Thomas E. Prod'homme, Shannon Argueta, Hongyun Zhao, Michael Gorgievski, Neha Diwangi, Edward Cochran, Bruce McCreedy, Yuxiao Wang, Daniel Getts. In vivo delivery of novel CD89 fusion receptor to myeloid cells by mRNA activates anti-tumor immunity [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 LB027.

Discovery of decreased ferroptosis in male colorectal cancer patients with KRAS mutations

Aberrant tumor metabolism is a hallmark of cancer in which metabolic rewiring can support tumor growth under nutrient deficient conditions. KRAS mutations occur in 35–45% of all colorectal cancer (CRC) cases and are difficult to treat. The relationship between mutant KRAS and aberrant metabolism in CRCs has not been fully explored and could be a target for intervention. We previously acquired non-targeted metabolomics data from 161 tumor tissues and 39 normal colon tissues from stage I-III chemotherapy naïve CRC patients. In this study, we revealed that only in male patients, tumors with KRAS mutations had several altered pathways that suppress ferroptosis, including glutathione biosynthesis, transsulfuration activity, and methionine metabolism. To validate this phenotype, MC38 CRC cells (KRASG13R) were treated with a ferroptosis inducer; RAS-selected lethal (RSL3). RSL3 altered metabolic pathways in the opposite direction to that seen in KRAS mutant tumors from male patients confirming a suppressed ferroptosis metabolic phenotype in these patients. We further validated gene expression data from an additional CRC patient cohort (Gene Expression Omnibus (GEO)), and similarly observed differences in ferroptosis-related genes by sex and KRAS status. Further examination of the relationship between these genes and overall survival (OS) in the GEO cohort showed that KRAS mutant tumors are associated with poorer 5-year OS compared to KRAS wild type tumors, and only in male patients. Additionally, high compared to low expression of GPX4, FTH1, FTL, which suppress ferroptosis, were associated with poorer 5-year OS only in KRAS mutant tumors from male CRC patients. Additionally, low compared to high expression of ACSL4 was associated with poorer OS for this group. Our results show that KRAS mutant tumors from male CRC patients have suppressed ferroptosis, and gene expression changes that suppress ferroptosis associate with adverse outcomes for these patients, revealing a novel potential avenue for therapeutic approaches.

Hedgehog Signaling Regulates Treg to Th17 Conversion Through Metabolic Rewiring in Breast Cancer.

The tumor immune microenvironment dynamically evolves to support tumor growth and progression. Immunosuppressive regulatory T cells (Treg) promote tumor growth and metastatic seeding in patients with breast cancer. Deregulation of plasticity between Treg and Th17 cells creates an immune regulatory framework that enables tumor progression. Here, we discovered a functional role for Hedgehog (Hh) signaling in promoting Treg differentiation and immunosuppressive activity, and when Hh activity was inhibited, Tregs adopted a Th17-like phenotype complemented by an enhanced inflammatory profile. Mechanistically, Hh signaling promoted O-GlcNAc modifications of critical Treg and Th17 transcription factors, Foxp3 and STAT3, respectively, that orchestrated this transition. Blocking Hh reprogramed Tregs metabolically, dampened their immunosuppressive activity, and supported their transdifferentiation into inflammatory Th17 cells that enhanced the recruitment of cytotoxic CD8+ T cells into tumors. Our results demonstrate a previously unknown role for Hh signaling in the regulation of Treg differentiation and activity and the switch between Tregs and Th17 cells in the tumor microenvironment.

Paradoxical activation of chronic lymphocytic leukemia cells by ruxolitinib in vitro and in vivo.

Chronic lymphocytic leukemia (CLL) is characterized by an aberrant cytokine network that can support tumor growth by triggering janus kinase (JAK)/STAT pathways. Targeting cytokine-signaling should then be a rational therapeutic strategy but the JAK inhibitor ruxolitinib failed to control and seemingly accelerated the disease in clinical trials. The effect of ruxolitinib on primary human CLL cells was studied in vitro and in vivo. Ruxolitinib increased phosphorylation of IRAK4, an important toll-like receptor (TLR)- signaling intermediate, in circulating CLL cells in vitro. It also enhanced p38 and NFKB1 phosphorylation while lowering STAT3 phosphorylation in CLL cells activated with TLR-7/8 agonists and IL-2. Among the cytokines made by activated CLL cells, high levels of IL-10 contributed strongly to STAT3 phosphorylation and inhibited TLR7 activity. Ruxolitinib limited TLR-mediated IL10 transcription and markedly reduced IL-10 production in vitro. It also decreased blood levels of IL-10 while increasing TNFα along with phospho-p38 expression and gene sets associated with TLR-activation in CLL cells in vivo. The bruton's tyrosine kinase inhibitor ibrutinib decreased IL-10 production in vitro but, in contrast to ruxolitinib, blocked initial IL10 transcription induced by TLR-signaling in vitro, decreased TNFα production, and deactivates CLL cells in vivo. These findings suggest the possible benefits of inhibiting growth factors with JAK inhibitors in CLL are outweighed by negative effects on potential tumor suppressors such as IL-10 that allow unrestrained activation of NFκB by drivers such as TLRs. Specific inhibition of growth-promoting cytokines with blocking antibodies or infusing suppressive cytokines like IL-10 might be better strategies to manipulate cytokines in CLL.

Oncogenic role of copper‑induced cell death‑associated protein DLD in human cancer: A pan‑cancer analysis and experimental verification.

Copper ions can bind directly to lipoylated components of the tricarboxylic acid (TCA) cycle, triggering the aggregation of mitochondrial lipoylated proteins and the destabilization of Fe-S cluster proteins, resulting in copper-dependent cell death. Dihydrolipoamide dehydrogenase (DLD) is a key protein of the TCA cycle and constitutes the E3 component of the α-ketoglutarate dehydrogenase complex, which is deeply interconnected with the mitochondrial electron transfer chain in the TCA cycle. Tumor cells demonstrate dependency on glutaminolysis fuelling to carry out the TCA cycle and essential biosynthetic processes supporting tumor growth. Therefore, DLD plays an important role in the tumor biological process. However, to the best of our knowledge, no pan-cancer analysis is currently available for DLD. Therefore, the present study first explored the DLD expression profile in 33 tumors in publicly available datasets, including TIMER2, GEPIA2, UALCAN, cBioPortal and STRING. TIMER2, GEPIA2 and UALCAN were used for exploring gene expression; survival prognosis was detected by GEPIA2; genetic alteration was analysed by cBioPortal; immune infiltration data was obtained from TIMER2; interacting proteins of DLD were detected by STRING. DLD was found to be highly expressed in colon, liver, lung, stomach, renal, corpus uteri endometrial and ovarian cancers compared with normal tissues, and its high expression was associated with poorer prognosis in ovarian cancer. To the best of our knowledge, the present study provided the first comprehensive pan-cancer analysis of the oncogenic role of DLD across different tumors types. As the expression of DLD in ovarian cancer was high, and high expression is associated with poor prognosis, experimental verification of DLD in ovarian cancer was conducted. In the present study, DLD expression was found to be high in the ovarian cancer OC3 cell line, compared with the normal ovarian epithelial IOSE80 cell line by reverse transcription-quantitative PCR analysis. After knockdown of DLD expression, it was found that DLD regulated metabolic pathways by suppressing the intracellular NAD+/NADH ratio, which then in turn suppressed tumor cell proliferation detected by MTT assay. In conclusion, the present pan-cancer analysis of DLD demonstrated that DLD expression was associated with the clinical prognosis, immune infiltration and tumor mutational burden in 33 tumor types, and experimental verification in ovarian cancer was conducted. These results may contribute to the understanding of the role of DLD in tumorigenesis.

Abstract 2877: Profiling of myeloid-derived suppressor cells in Pten-deficient in prostate cancer progression

Abstract Myeloid-derived suppressor cells (MDSCs) are a heterogenous population of immature immune cells that expand during cancer and can induce potent immune suppression. These cells play critical roles in supporting tumor growth and progression and their induction has been associated with the inactivation of PTEN. To date, few therapies targeting these cells are available which is partly due to their increasingly complex nature and context-dependent functions. Moreover, there is no clear definition to identify these cells. Enhancing our understanding of this cell population will aid in developing more effective cancer therapies. Here, we used gene expression profiling, flow cytometry, and quantitative immunohistochemistry to characterize tumor-infiltrating and circulating MDSCs in prostate carcinogenesis and progression in transgenic mouse models of prostate cancer driven by the conditional inactivation of Pten and Trp53. Transcriptomic profiling revealed enrichment of various myeloid-derived cell signatures in the early stages of prostate cancer including MDSCs, macrophages, and neutrophils. Flow cytometric analysis confirmed the increased infiltration of CD11b+/Ly6G+ (polymorphonuclear MDSCs (pMDSCs)) and CD11b+/Ly6C+ (monocytic MDSCs (mMDSCs)) cells in prostate tumors. The temporal dynamics of tumor-infiltrating myeloid cells were further profiled and showed that pMDSC and mMDSC abundances were 1.6 and 5.7-fold higher, respectively, in older mice with late-stage locally invasive adenocarcinomas (AdCa) compared to younger mice with early-stage prostatic intraepithelial neoplasia (PIN). In both instances, pMDSCs comprised most of the leukocyte infiltrate, however, mMDSCs tended to be positively correlated with tumor burden in AdCa but not PIN. In peripheral blood, CD44+/CD62L+ immature neutrophils were associated with high tumor burden in aged mice. Treatments targeting the androgen receptor (AR) signaling further exacerbated pMDSC infiltration in tumors and was associated with resistance to second androgen receptor-targeted agent (ARTA) therapy in a model of castration resistant prostate cancer. Our findings indicate that MDSCs are a prominent population in Pten-null prostate cancer and are implicated with resistance to prostate cancer treatment. MDSCs constitute a potentially targetable population and these models serve as viable platforms to further investigate their biological activity and further evaluate novel MDSC-directed therapies. Citation Format: Marco A. De Velasco, Yurie Kura, Noriko Sako, Naomi Ando, Kazuko Sakai, Eri Banno, Shogo Adomi, Mitsuhisa Nishimoto, Takafumi Minami, Yasunori Mori, Kazutoshi Fujita, Masahiro Nozawa Nozawa, Kazuhiro Yoshimura, Kazuto Nishio, Hirotsugu Uemura. Profiling of myeloid-derived suppressor cells in Pten-deficient in prostate cancer progression [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 2877.

Abstract 5918: Interrogating host-intratumoral microbial interactions in pancreatic cancer

Abstract Cancer is increasingly becoming a rising cause of mortality worldwide. Microbiota, both within the gut and tumors, has emerged as a significant player influencing tumor growth and responses to therapies. The tumor niche provides a privileged microenvironment for microbial colonization. Recent evidence links microbiota and pancreatic tumorigenesis. Pancreatic ductal adenocarcinoma (PDAC), is an aggressive cancer surrounded by a highly immuno-suppressive tumor microenvironment (TME) which limits efficacy of most available therapies. We have previously reported that rare long-term survival in pancreatic cancer is associated with an intratumoral microbial signature which correlates with enhanced TME immunoactivation, suggestive of microbial mediated immune cell recruitment. A gut-to-tumor microbial crosstalk was also found in a human-to-mouse Fecal Microbiota Transplant (FMT) tumor model. While we have identified the vital role of microbiota in affecting tumor immunity, there is still a gap of knowledge about local microbial interactions within TME. Deeper understanding of the microbial mediated events that are triggered and follow PDAC development, which act to induce and support tumor growth, would provide us with potential novel targets that could be blocked to reverse PDAC immunosuppression and tumor growth. To interrogate the features of the pancreatic tumor microbial niche, we performed spatial co-detection of microbial and host targets to identify the cellular compartment which interacts with microbes inside the TME in clinical samples. We developed novel qualitative and quantitative imaging methodologies for evaluating crosstalk between the host and microbes. We also evaluated the effect of microbial burden on transcriptomic changes in host cells through multiple spatial sequencing approaches. Overall, we dissect the functional role of microbes in orchestrating TME organization and their effect on tumor signaling. Citation Format: Vidhi Chandra, Hajar Rajaei, Seyda Baydogan, Javier Gomez, Sammy Ferri-Borgogno, Anirban Maitra, Erick Riquelme, Ismet Sahin, Jared Burks, Michael Kim, Florencia McAllister. Interrogating host-intratumoral microbial interactions in pancreatic 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 5918.

Abstract 3695: Mitochondrial uncoupling reverses reductive carboxylation in cancer

Abstract When electron transport chain (ETC) activity is inhibited upon hypoxia or when cultured in suspension, reductive carboxylation plays an essential role in supporting tumor growth through converting α-ketoglutarate (α-KG) to citrate, which is converted to acetyl-coenzyme A (acetyl-CoA) for lipogenesis. However, there is no effective way to target reductive carboxylation for tumor therapy. In this study, we use the mitochondrial uncoupler niclosamide ethanolamine (NEN) and BAM15 to reverse reductive carboxylation in cancer cells. Uncoupler treatment activates ETC and increases the cellular NAD+/NADH ratio. Using U-13C-glutamine and 1-13C-glutamine tracers, we discovered that uncoupler treatment accelerates the oxidative TCA cycle and blocks reductive carboxylation, particularly under hypoxia and spheroid culture condition. Uncoupler treatment significantly reduces tumor cell proliferation, survival and sphere formation. In addition, the intracellular acetyl-CoA levels are significantly decreased by NEN treatment. Furthermore, lipidomics analysis showed that NEN treatment reduced fatty acid abundance and altered the lipid composition under both normoxia and hypoxia. Together, these data demonstrate mitochondrial uncoupling redirects the α-KG flux from reductive carboxylation back to the oxidative TCA cycle, highlighting that the ETC activity and NAD+/NADH ratio is the key switch that determines the metabolic fate of α-KG. Reversing reductive carboxylation could be one key mechanism that mitochondrial uncoupler inhibits tumor growth. Citation Format: Haowen Jiang, Clifford Jiajun He, Albert M. Li, Bo He, Yang Li, Jiangbin Ye. Mitochondrial uncoupling reverses reductive carboxylation in 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 3695.

Abstract 3702: Serine promotes aggressive phenotype in renal cancer

Abstract Tumor cells are known to have increased demand for nutrients to support proliferation. Among the most highly utilized nutrients by tumor cells are nonessential amino acids (NEAAs). While the role of NEAAs in supporting tumor growth is well-established, their role in supporting aggressive phenotypes such as migration and invasion is poorly understood. Yet, the major cause of morbidity from malignancies such as renal cell carcinoma (RCC) is metastasis. Through an unbiased approach, we assayed the role of NEAAs in promoting the migration of RCC cells. We demonstrate that exogenous serine and glutamine are essential and sufficient to support aggressive phenotypes in RCC. Moreover, the availability of both NEAAs is critical for the expression of the proinvasive transcription factor SNAIL. Our data converge on the role of these two NEAAs in supporting the translation of this factor. Perturbations that limit the availability and/or synthesis of either result in translational reprogramming through the integrated stress response (ISR) that leads to loss of SNAIL1 expression and attenuates aggressive phenotypes. Our findings associate nutrient status to the ISR including ER stress. Collectively, our study highlights new insights for NEAA metabolism in supporting aggressive tumor phenotypes and could reveal novel approaches to mitigate metastasis by targeting NEAA availability and/or utilization. Citation Format: Suman Karki, Anirban Kundu, Garret Brinkley, Hyeyoung Nam, Kayla Goliwas, Jessy Deshane, Sunil Sudarshan. Serine promotes aggressive phenotype in renal 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 3702.

Abstract 5017: Simultaneous targeting of EphA3 on glioblastoma and tumor microenvironment to overcome resistance to CART cell therapy in brain cancer

Abstract Glioblastoma multiforme (GBM) is the most aggressive and common form of brain tumor, and it is characterized by an immunosuppressive tumor microenvironment (TME) that supports tumor growth and pathology. An integral part of the GBM stroma is the mesenchymal stem cells (MSC), which promote GBM growth. Receptor tyrosine kinase EphA3, a member of the Eph family, is overexpressed in GBM tumors and in MSCs within TME, making it an attractive target for Chimeric antigen receptor T-cell (CART) therapy. CART has proven incredible promise in certain hematological malignancies therapy but remained short in solid tumors, particularly GBM. We hypothesize that concurrent targeting of cancers and TME by EphA3-CART can be a potential therapeutic option in GBM. We first showed the expression of the EphA3 receptor by Immunohistochemistry and western blot on GBM patient-derived xenograft (PDX), as well as on the SNB-19 and U87 human GBM cell lines and adipose-derived MSCs using flow cytometry. We then generated EphA3-CAR construct derived from a clinically validated anti-EphA3 scFv cloned in a lentiviral vector containing CD28 and CD3ζ, and generated EphA3 CART cells with over 90% efficiency. EphA3 CART cells demonstrated potent antigen specific effector functions. To demonstrate the antitumor activity in vivo, we subcutaneously grafted 1 × 106 GBM cells per NOD-SCID-γ-/- mice and at ~150-300 mm3 tumor volume, mice were then treated with 5 × 106 EphA3-CART or un-transduced (UTD) T cells control. Tumors were monitored by bioluminescence imaging (BLI) and caliper measurements, and mice were followed for survival. Mice treated with EphA3 CART cells exhibited a significant reduction in tumor volume (p<0.005), and prolonged overall survival (p=0.0015). Finally, we tested the ability of EphA3-CART cells to overcome MSC induced CART cell suppression by co-culturing EphA3-CART cells with MSC and EphA3+ GBM target cells while using the CD19+ mantle cell lymphoma cell line JeKo-1 and CART19 as control. MSC conditioned coculture of GBM and CART showed significant suppression of CAR19 in the CART19 - JeKo-1 system (p=000.3), but no significant suppression of EphA3-CART cells. In summary, our results indicate that EphA3 CART cells exhibited potent and specific antitumor activity in vitro and in vivo and ameliorated MSC induced inhibition of CART cell functions, representing a potentially promising therapeutic option in GBM. Citation Format: Ekene J. Ogbodo, Michael W. Ruff, Reona L. Sakemura, Claudia ManriquezRoman, Truc Huynh, James H. Girsch, Olivia L. Sirpilla, Kun Yun, Carli M. Stewart, Ismail Can, Lionel K. Fonkoua, Mehrdad Hefazi, Elizabeth L. Siegler, Saad S. Kenderian. Simultaneous targeting of EphA3 on glioblastoma and tumor microenvironment to overcome resistance to CART cell therapy in brain 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 5017.

Abstract 2321: Tumor-derived extracellular vesicles induce macrophages immunosuppressive polarization to promote ovarian cancer progression

Abstract Background: Communication between cancer cells and surrounding cells in the tumor microenvironment (TME) is critical for tumor metastasis. There has been an increasing focus on how tumor-derived extracellular vesicles (EVs) contribute to the complex intracellular communications within the TME. More recent characterizations in both mice and humans have demonstrated that expression of the immune checkpoint molecule, programmed death ligand-1 (PD-L1) on EVs contributes to systemic immunosuppression, higher overall tumor burdens, and decreased survival of a variety of cancer types. In ovarian carcinoma, macrophages are reprogrammed toward pro-tumorigenic phenotypes, including the release of anti-inflammatory cytokines and expression of immunosuppressive molecules such as arginase-1 and PD-L1. However, a detailed mechanism that explains how tumor-derived EVs induce immunosuppressive phenotype in macrophages is necessary to develop novel immunotherapy strategies for advanced ovarian cancer treatment. The present study aimed to examine the effect of EVs derived from ovarian cancer cells on macrophage functions. Methods: We isolated murine peritoneal macrophages from naïve C57BL/6 female mice and co-cultured the macrophages with EVs derived from ovarian cancer (ID8-Trp53-/-Brca2-/-) cell lines. The expression of PD-L1, CD206, interleukin-6 (IL-6), and other inflammatory cytokines on EVs treated macrophages was evaluated using flow cytometry and a cytokine array kit. Further, we created Rab27aKO ID8 cell lines to generate ovarian cancer in vivo mouse models for studying the effect of exogenous EVs on the immunosuppressive ability of macrophages and tumor progression. Results: Our results indicate that EVs uptake efficiency of macrophages is higher than fibroblast, endothelial, and mesothelial cells. We found that tumor-derived EVs can significantly upregulate the expressions of PD-L1, CD206, and IL-6 on macrophages to support tumor growth. Treatment of macrophages with EVs also decreased their phagocytic ability. In addition, our data show that in the Rab27aKO ovarian cancer in vivo mouse model, intravenous injection of tumor-derived EVs increased the tumor burden, metastasis, and ascites accumulation as compared to PBS control. EVs treatment increased the infiltration of tumor-associated macrophages (TAM) in ascites. We also found increased expression of PD-L1 and CD206 on TAM isolated from ascites. Conclusion: We uncover a tumor-promoting role of ovarian cancer-derived EVs on reprogramming TAM towards pro-tumor phenotype. Our data suggest that tumor-derived EVs contribute to the formation of an immunosuppressive microenvironment to promote ovarian cancer growth. Citation Format: Sonam Mittal, Ishaque Pulikkal Kadamberi, Prachi Gupta, Sudhir Kumar, Jasmine George, Anjali Geethadevi, Pradeep Chaluvally-Raghavan, Sunila Pradeep. Tumor-derived extracellular vesicles induce macrophages immunosuppressive polarization to promote ovarian cancer progression [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 2321.

Abstract 6253: SP-3164, a novel molecular glue degrader with activity in preclinical models of multiple myeloma

Abstract Multiple myeloma (MM) makes up approximately 10% of all hematologic malignancies, with increasing incidence worldwide. Though treatment options for newly diagnosed patients have evolved in recent years, they are not curative, and relapse is common with 2,500-3,000 relapsed or refractory (R/R) MM US patients seeking novel treatments, annually. Cereblon (CRBN)-binding Ikaros and Aiolos (I/A) protein degraders (i.e., lenalidomide (LEN) and pomalidomide (POM)) have had great success in treating MM. However, due to the unstable chiral nature of the CRBN-binding moiety, common to these molecules, many exist as racemic mixtures (1:1 mixture of interconverting (R)- and (S)-enantiomers). A growing body of evidence suggests that the (S)- enantiomer is the active anticancer species, while the (R)-enantiomer is inactive and potentially results in undesired activity. The ability to stabilize the active (S)- enantiomer represents a potential strategy to improve therapeutic outcomes. We are developing SP-3164, the deuterium-stabilized (S)-enantiomer of avadomide (AVA), an I/A-degrading molecular glue which has been studied in over 400 patients, demonstrating safety and activity in hematologic diseases. Our in vitro data demonstrate that SP-3164 more potently and rapidly degrades the cancer-promoting transcription factors, I/A, compared to LEN, POM, and AVA, while the stabilized (R)-enantiomer, SP-3165, neither binds CRBN nor degrades I/A. In preliminary in vivo studies, SP-3164 elicited significant tumor growth inhibition (TGI). Here, we investigate the activity of SP-3164 in MM, compared to established treatment regimens. SP-3164’s potential to degrade Aiolos in MM.1S cells was compared to SP-3165, AVA, and POM. SP-3164 rapidly and robustly degraded Aiolos in a time- and dose-dependent manner, more potently than AVA and POM, while SP-3165 demonstrated minimal Aiolos degradation. To investigate the effect of SP-3164 on cell survival, we treated NCI-H929 cells with SP-3164 (0.1 µM, 1 µM, and 10 µM) and SP-3165 (1 µM) and assessed apoptosis by flow cytometry. SP-3164 induced dose-dependent early and late apoptosis after 72 hours, while SP-3165 showed no induction of apoptosis. SP-3164’s in vivo activity was assessed and compared to SP-3165, LEN, and POM in an NCI-H929 mouse xenograft model. SP-3164 showed significant TGI as a single agent while SP-3165 seemed to support tumor growth. LEN and POM demonstrated minimal TGI. When combined with dexamethasone (DEX), SP-3164 had improved TGI compared to the combination of POM+DEX. These preclinical data demonstrate that SP-3164 is a potent CRBN-binding molecular glue with the ability to rapidly degrade cancer-promoting transcription factors and induce apoptosis in vitro. In vivo, SP-3164 has superior single agent and combination activity compared to approved molecular glues. These data support the continued development as a novel therapy in MM. Citation Format: Aundrietta D. Duncan, Daniela Y. Santiesteban, Nadeem Q. Mirza, Steve Horrigan, Sheila DeWitt, Vincent Jacques, P. Leif Bergsagel. SP-3164, a novel molecular glue degrader with activity in preclinical models of multiple myeloma [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 6253.

Differential Transcriptome Responses in Human THP-1 Macrophages Following Exposure to T98G and LN-18 Human Glioblastoma Secretions: A Simplified Bioinformatics Approach to Understanding Patient-Glioma-Specific Effects on Tumor-Associated Macrophages

A common theme in glioma disease progression is robust infiltration of immune cells within the tumor microenvironment, resulting in a state of chronic inflammation. This disease state is characterized by an abundance of CD68+ microglia and CD163+ bone marrow-derived macrophages with the greater the percentage of CD163+ cells, the poorer the prognosis. These macrophages are "cold," in that their phenotype is of an alternatively activated state (M0-M2-like) supporting tumor growth rather than being engaged with classically activated, pro-inflammatory, and anti-tumor activities, referred to as "hot", or M1-like. Herein, we have developed an in vitro approach that uses two human glioma cell lines, T98G and LN-18, which exhibit a variety of differing mutations and characteristics, to demonstrate their disparate effects on differentiated THP-1 macrophages. We first developed an approach to differentiating THP-1 monocytes to macrophages with mixed transcriptomic phenotypes we regard as M0-like macrophages. We then found that supernatants from the two different glioma cell lines induced different gene expression profiles in THP-1 macrophages, suggesting that from patient to patient, gliomas may be considered as different diseases. This study suggests that in addition to standard glioma treatment modalities, transcriptome profiling of the effects of cultured glioma cells on a standard THP-1 macrophage in vitro model may lead to future druggable targets that aim to reprogram tumor-associated macrophages towards an anti-tumor phenotype.

Cancer-Associated Fibroblast: Role in Prostate Cancer Progression to Metastatic Disease and Therapeutic Resistance

Prostate cancer (PCa) is one of the most common cancers in European males. Although therapeutic approaches have changed in recent years, and several new drugs have been approved by the Food and Drug Administration (FDA), androgen deprivation therapy (ADT) remains the standard of care. Currently, PCa represents a clinical and economic burden due to the development of resistance to ADT, paving the way to cancer progression, metastasis, and to long-term side effects induced by ADT and radio-chemotherapeutic regimens. In light of this, a growing number of studies are focusing on the tumor microenvironment (TME) because of its role in supporting tumor growth. Cancer-associated fibroblasts (CAFs) have a central function in the TME because they communicate with prostate cancer cells, altering their metabolism and sensitivity to drugs; hence, targeted therapy against the TME, and, in particular, CAFs, could represent an alternative therapeutic approach to defeat therapy resistance in PCa. In this review, we focus on different CAF origins, subsets, and functions to highlight their potential in future therapeutic strategies for prostate cancer.

Emerging Role of NRF2 Signaling in Cancer Stem Cell Phenotype.

Cancer stem cells (CSCs) are a small population of tumor cells characterized by self-renewal and differentiation capacity. CSCs are currently postulated as the driving force that induces intra-tumor heterogeneity leading to tumor initiation, metastasis, and eventually tumor relapse. Notably, CSCs are inherently resistant to environmental stress, chemotherapy, and radiotherapy due to high levels of antioxidant systems and drug efflux transporters. In this context, a therapeutic strategy targeting the CSC-specific pathway holds a promising cure for cancer. NRF2 (nuclear factor erythroid 2-like 2; NFE2L2) is a master transcription factor that regulates an array of genes involved in the detoxification of reactive oxygen species/electrophiles. Accumulating evidence suggests that persistent NRF2 activation, observed in multiple types of cancer, supports tumor growth, aggressive malignancy, and therapy resistance. Herein, we describe the core properties of CSCs, focusing on treatment resistance, and review the evidence that demonstrates the roles of NRF2 signaling in conferring unique properties of CSCs and the associated signaling pathways.