Development Of Metastases Research Articles

CD4+ Regulatory T Cells in Human Cancer: Subsets, Origin, and Molecular Regulation.

CD4+CD25hiFOXP3+ regulatory T cells (Treg) play major roles in the maintenance of immune tolerance, prevention of inflammation, and tissue homeostasis and repair. In contrast with these beneficial roles, Tregs are abundant in virtually all tumors and have been mechanistically linked to disease progression, metastases development, and therapy resistance. Tregs are thus recognized as a major target for cancer immunotherapy. Compared with other sites in the body, tumors harbor hyperactivated Treg subsets whose molecular characteristics are only beginning to be elucidated. Here, we describe current knowledge of intratumoral Tregs and discuss their potential cellular and tissue origin. Furthermore, we describe currently recognized molecular regulators that drive differentiation and maintenance of Tregs in cancer, with a special focus on those signals regulating their chronic immune activation, with relevant implications for cancer progression and therapy.

Potential role of the Eph/ephrin system in colorectal cancer: emerging druggable molecular targets.

The Eph/ephrin system regulates many developmental processes and adult tissue homeostasis. In colorectal cancer (CRC), it is involved in different processes including tumorigenesis, tumor angiogenesis, metastasis development, and cancer stem cell regeneration. However, conflicting data regarding Eph receptors in CRC, especially in its putative role as an oncogene or a suppressor gene, make the precise role of Eph-ephrin interaction confusing in CRC development. In this review, we provide an overview of the literature and highlight evidence that collaborates with these ambiguous roles of the Eph/ephrin system in CRC, as well as the molecular findings that represent promising therapeutic targets.

Brain Metastasis of Non-small Cell Lung Cancer After Disease-Free Survival of 5 years: Case Series and Comprehensive Literature Review

BackgroundIn the treatment of non-small cell lung cancer (NSCLC), a disease-free survival (DFS) of 5 years is a criterion for cure. This study aimed to evaluate the characteristics and outcomes of patients with brain metastases of NSCLC after a DFS of 5 years (late recurrent brain metastasis, LRBM). MethodsWe reviewed 1,281 consecutive patients with brain metastasis of lung cancer at a single institute between November 2014 and December 2022. Relevant articles were retrieved from PubMed. Only peer-reviewed journals published in English were included. ResultsSix patients (0.47%) showed LRBM. Three were male. The median age at lung cancer diagnosis was 45 years. The histological diagnosis of all patients was adenocarcinoma. Driver gene mutations were observed in five patients. The median latency period from lung cancer treatment to the development of brain metastasis was 13 years. All patients had no metastasis to any other organs and underwent craniotomies. The median follow-up duration after craniotomy was 3.5 years. No local intracranial recurrences were observed. Three patients had distant intracranial recurrences at 7, 2, and 0.6 years after craniotomy. Five patients survived for 8, 4, 3, 2, and 0.3 years after craniotomy. One patient experienced re-recurrence in the lung 4 years after craniotomy and died 3.7 years later. In our systematic review, only six studies described LRBM of NSCLC. ConclusionsLRBM is rare in patients with NSCLC. In our institution, many of these patients harbored driver gene mutations, and achieved long-term survival with aggressive local therapy. Multicenter analysis is mandatory.

Bone metastases in oral squamous cell carcinoma: A real-world retrospective study based on the SEER database

BackgroundBone metastases are rare in oral squamous cell carcinoma (OSCC). It has not been defined on the risk and prognosis of OSCC patients with bone metastases. The purpose of this study was to assess the factors associated with the development and prognosis of bone metastases among OSCC patients. MethodsDemographic and clinicopathological characteristics of OSCC patients diagnosed between 2010 and 2019 was retrieved from the Surveillance, Epidemiology, and End Results (SEER) database. To explore risk factors for developing bone metastases and prognosis, the univariate and multivariate logistic and Cox regression analysis were performed, further the predictive nomogram models were constructed. ResultsThe incidence rate of bone metastases in newly diagnosed OSCC patients was 0.91 % (95 %CI 0.81% –1.02 %). Ultimately, 137 OSCC patients with bone metastases and 19,469 OSCC patients without bone metastases were included in the present study. Pathological grade, primary site, T/N stage and distant organ metastases (liver/lung/brain) were independently associated with the risk of developing bone metastases among OSCC patients. The C-index of a constructed risk-predicting nomogram was 0.86 (95 %CI 0.83–0.89). Multivariate Cox regression analysis indicated that lung metastases, the use of surgery as well as chemotherapy were three independent prognostic factors. The C-indexes of constructed risk-predicting nomograms were 0.70 (95 %CI 0.65–0.75), 0.68 (95 %CI 0.63–0.73) for OS and CSS, respectively. Calibration plots demonstrated an agreementbetween the established nomogram's predicted survival and actual survival. In addition, decision curve analysis (DCA) indicated these established nomograms had considerable net benefits and clinical utilities. ConclusionThis study defined the risk and prognostic factors for bone metastases among OSCC patients and the established nomograms were well calibrated for discrimination to predict bone metastasis development and prognosis.

Mammographic density changes after neoadjuvant chemotherapy in triple-negative breast cancer: Association with treatment and survival outcome

PurposeTo investigate the association of mammographic breast density with treatment and survival outcomes in patients with triple-negative breast cancer (TNBC) undergoing neoadjuvant chemotherapy (NAC). MethodsThis retrospective study evaluated 306 women with TNBC who underwent NAC followed by surgery between 2010 and 2019. The baseline density and the density changes after NAC were evaluated. Qualitative breast density (a-d) was evaluated using the Breast Imaging Reporting and Data System. Quantitative breast density (%) was evaluated using fully automated software (the Laboratory for Individualized Breast Radiodensity Assessment) in the contralateral breast. Multivariable logistic regression analysis was used to evaluate the association between breast density and pathologic complete response (pCR), stratified by menopausal status. Cox proportional hazard regression analysis was used to evaluate the association among breast density, the development of contralateral breast cancer, and the development of locoregional recurrence and/or distant metastasis. ResultsContralateral density reduction ≥10 % was independently associated with pCR in premenopausal women (odds ratio [OR], 2.5; p = 0.022) but not in postmenopausal women (OR, 0.9; p = 0.823). During a mean follow-up of 65 months, 10 (3 %) women developed contralateral breast cancer, and 68 (22 %) women developed locoregional recurrences and/or distant metastases. Contralateral density reduction ≥10 % showed no association with the occurrence of contralateral breast cancer (hazard ratio [HR], 3.1; p = 0.308) or with locoregional recurrence and/or distant metastasis (HR, 1.1; p = 0.794). ConclusionIn premenopausal women, a contralateral breast density reduction of ≥10 % after NAC was independently associated with pCR, although it did not translate into improved outcomes.

Abstract 5525: Tissue-resident cytotoxic T cell infiltration predicts metachronous colorectal cancer metastasis

Abstract Background: Identifying patients at high risk for metachronous colorectal cancer metastasis is essential for improving prognosis. The balance between host immune regulation and tumor immune evasion ultimately permits or prevents cancer progression. Lymphocytic infiltration in colorectal cancer can predict long-term clinical outcomes. However, these lymphocytes' origin, subtype and function have yet to be adequately explored. We investigated the association between the development of metastasis and CD8+T cells expressing the integrin protein CD103, a marker of tissue-resident memory T cells. Methods: In this retrospective, case-control matched study, we conducted multiplex immunofluorescence staining of tumor samples from 124 patients with colorectal cancer. Tissue microarrays containing representative cores of the central tumor, invasive margin, and adjacent normal tissue were immunostained for CD3, CD8, CD103, pSMAD3, and cytokeratin, using tyramide signal amplification. Cells were quantified using StrataQuest digital image analysis software, with intratumoral and stromal regions analyzed separately. Kruskal-Wallis one-way analysis of variance with subsequent Dunn’s test for pair-wise comparisons was performed using the Bonferroni method of multiple-comparison correction. Results: Central tumor and invasive margin CD3+ densities were associated with synchronous metastasis. Compared to non-metastatic patients, those who went on to develop metachronous metastasis (n=42) had a low proportion of intra-epithelial CD8+CD103+ T cells at the central tumor (non-metastatic: 32.8%, IQR 15.0-42.7%; metachronous metastasis: 12.9%, IQR 2.08-28.4%; P = 0.013). Similarly, patients with metachronous metastasis had a low proportion of stromal CD8+CD103+ T cells at the invasive margin (non-metastatic: 3.51%, IQR 1.83-6.55%; metachronous metastasis: 1.75%, IQR 0.62-3.72%; P = 0.019). On multivariate Cox regression of histological features, amongst patients with metastasis, significant overall survival prognostic markers included a low proportional CD8+CD103+ T cell infiltration (HR 2.41, 95%CI 1.16-5.01, P = 0.019), mucinous features (HR 4.28, 95%CI 1.98-9.24, P < 0.001), and the presence of perineural invasion (HR 2.75, 95%CI 1.28-5.89, P < 0.001). Conclusion: CD8+CD103+ lymphocytes may protect from the development of colorectal metastasis. Proportional CD8+CD103+ T cell infiltration is a promising prognostic marker in colorectal adenocarcinoma for the development of metachronous metastasis, and, amongst patients with metastasis, it is a prognostic marker of overall survival. Citation Format: Ryan Cohen, Tracey Lee-Pullen, Timothy Miller, Shadi Pirasteh, Cameron Platell, Katie Meehan, Kathy Fuller, Melanie McCoy. Tissue-resident cytotoxic T cell infiltration predicts metachronous colorectal cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5525.

Abstract 5064: Wild type KRAS amplification as de novo oncogenic driver in non-small cell lung cancer

Abstract Introduction: Oncogenic KRAS mutations define subsets of non-small cell lung cancer (NSCLC) with unique clinicopathologic and genomic features, and the recent development of direct KRAS inhibitors has changed the treatment landscape of these patients (pts). However, whether KRAS amplification is oncogenic and defines unique subset of potentially targetable NSCLCs is currently unknown. Methods: Clinicopathologic and genomic data were abstracted from multiple independent cohorts of NSCLCs which underwent tumor genomic profiling at the Dana-Farber Cancer Institute (Cohort 1), AACR-GENIE v.13, TCGA, and other 212 studies (Cohort 2). Whole transcriptome sequencing and quantitative proteomics data from the The Cancer Genome Atlas (TCGA) and the Cancer Cell Lines Encyclopedia (CCLE) were used to correlate KRAS amplification with KRAS RNA levels and protein expression. KRAS doxycycline-inducible models were generated to determine in vitro and in vivo oncogenicity of wild-type KRAS overexpression. Results: Among 15,341 pts with NSCLC identified, KRAS amplification was identified in 355 (2.4%) cases. Compared to KRAS not amplified cases, pts with KRAS amplified NSCLC were more likely to be males (52.4% vs 45.6%, p=0.01), have a history of smoking (82.1% vs 64.2%, p<0.01), and higher median pack-years (35 vs 23.5, p<0.01). KRAS amplification was also associated with higher median aneuploidy levels (as fraction of genome altered) (30.4% vs 14.3%, p<0.01), tumor mutational burden (p<0.01), and increased median PD-L1 expression (20% vs 5%, p=0.01). KRAS amplified cases were enriched with KRAS, POLE2, SLC34A2 and PALB2 mutations, while EGFR mutations were mutually exclusive (Q<0.1). Among NSCLC samples with transcriptomic and proteomic profiling from the TCGA and CCLE cohorts, KRAS amplification was associated with significantly increased KRAS mRNA (p<0.01) and protein expression (p<0.01), compared to KRAS diploid samples. Among pts with clinical outcomes data available (N=9,335), median overall survival (OS) from the date of diagnosis was significantly shorter in pts with KRAS amplified vs KRAS diploid genotype in both KRAS mutant (HR: 0.71, P=0.02) and KRAS WT (HR: 0.74, P=0.02) NSCLCs. In KRAS doxycycline-inducible models (BEAS-2B cells) we demonstrated increased cell proliferation and MAPK activation upon doxycycline-induced KRAS expression. In vivo, sustained expression of KRAS in animals constantly fed with doxycycline-diet triggered tumor formation and development of metastasis, indicating that WT KRAS overexpression is oncogenic. Conclusion: KRAS amplification defines a novel subset of NSCLCs characterized by distinct clinicopathologic and genomic features, and worse survival. Developing novel therapeutic strategies to target KRAS amplification may improve outcomes in pts with NSCLC. Citation Format: Biagio Ricciuti, Sandra V. Michelina, Joao Alessi, Xinan Wang, Federica Pecci, Alessandro Di Federico, Malini Gandhi, Giuseppe Lamberti, Enrico Patrucco, Lynette Sholl, Andrew Aguirre, Chiara Ambrogio, Mark Magdi Awad. Wild type KRAS amplification as de novo oncogenic driver in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5064.

Abstract 3392: Generation and characterization of transgenic oncopig model for lung cancer

Abstract Lung cancer (LC) is the leading cause of cancer-associated death in the United States. Preclinical findings in small animal models do not translate into human clinics. There is an urgent need to develop relevant preclinical large animal models for LC. We describe a novel method to induce LC in transgenic pigs carrying Cre-inducible KrasG12D and TrP53R167H mutations (Oncopigs). The Oncopigs (n=12; 9 females, and 3 males) at 9 weeks of age were anesthetized and adenovirus (1 × 1011 PFU) carrying Cre recombinase gene (Ad-Cre) ± polybrene (1:100) ± IL-8 (5 ng/ml) was injected via flexible bronchoscopy with two techniques: (1) Bronchial lavage (n=6) and (2) Transbronchial needle injection (n=6) into different lung lobes. As controls, a combination of polybrene ± IL-8 was injected without AdCre into the contralateral lobes in the same pigs (n=8). Oncopigs were monitored via clinical monitoring, blood counts, basic metabolic panel, and contrast-enhanced computed tomography (CT) imaging for LC progression and metastasis at 3-, 4-, 7-, 10-, 16-, and 26 weeks post-intervention. All animals tolerated the injections with expected weight gains. Blood counts and metabolic panels remained normal during LC progression. At the site of injection/lavage, lung masses were detected on CT imaging at 3 weeks post-injections. However, a decrease in masses was observed on CT at 7 weeks post-intervention. The decrease in size of the lung masses coincided with increasing attenuation. No distant metastases were observed on CT imaging. Lavage-based lesions appeared to be more heterogeneous with surrounding inflammatory changes. Transbronchial-injection-based lesions appeared more consolidated and coin-shaped without surrounding inflammatory changes. Control injection sites did not show any mass growth on CT imaging. Immunohistochemistry analysis on lung tumors revealed increased pancytokeratin, trichrome, E-cad, Ki-67, IBA, and CD3 expression. Further, immunofluorescence revealed decreased E-Cad, CK-19, and Zo-1 expression, whereas increased expression of N-Cad, FN1, snail, CD44, α-SMA, and γ-catenin, was observed in the LC and metastatic tissue compared to normal. We successfully generated and characterized a novel transgenic Oncopig LC model. There is robust tumor production status post AdCre delivery. One of four Oncopigs had carcinomatous metastatic skin growth. The remaining 7 Oncopigs are monitored longitudinally for tumor growth and development of metastasis. Citation Format: Kirtan Joshi, Nagabhishek Sirpu, Amanda Schmelzle, Ravikanth Poonooru, Benjamin Nelson, Pradeep Subramanyam, Colleen Garrett, Mariana Sponchiado, Sarah Schlink, Samantha Gerb, Jesse Porter, Dae Kim, Jeffrey Kunin, Jeffrey Bryan, Timothy Hoffman, Bhanu Telugu, Jussuf Kaifi, Satyanarayana Rachagani. Generation and characterization of transgenic oncopig model for lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3392.

Abstract 2763: A specific ribomethylome pattern in lung cancer is associated with increased risk of metastasis

Abstract Non-coding RNAs drive cancer phenotypes and are associated with patients’ outcome. SnoRNAs are required for the 2’-O-methylation (2’-O-Me) and pseudouridylation of ribosomal RNA (rRNA) thus being essential for ribosomal biogenesis and function. So far, the role of rRNA methylation (ribomethylation) for non-small cell lung cancer (NSCLC) pathogenesis is unknown. To investigate the role of ribomethylation we included samples from 92 patients with lung adenocarcinoma (pathological stage IA to IIB) for comprehensive multi-omics profiling. Amongst transcriptomics, small RNA sequencing, proteomics, and whole exome sequencing, ribomethylation as epitranscriptomic dimension was analyzed using RiboMethSeq. We focused the analysis on complete tumor resection samples. Here 47 out of 106 2’-O-Me sites were fully methylated in all tumor samples suggesting a crucial role for methylation at this position. Surprisingly, 59 sites had a dynamic methylation pattern. By combining ribomethylation sequencing data of dynamic sites with whole-exome-sequencing as well as transcriptome and proteome analyses using a multi-omics factor analysis (MOFA), we discovered a 2’-O-Me signature in a subset of NSCLC patients with a high risk of metastasis and poor prognosis. We termed the patient subset, with underlying ribomethylation signature, epitranscriptomic pro-metastatic phenotype (EPROMET). This phenotype was not associated with genetic mutations as analyzed by exome sequencing. Analysis of gene sets in both transcriptomics and proteomics showed an upregulation of secreted and extracellular matrix proteins in EPROMET patients. Alongside, the ribomethylation site with major contribution to the EPROMET signature; 18S-Um799, mediated through SNORD105/105B, was found to be the most dynamic within the dataset. It also showed the largest difference between EPROMET and non-EPROMET patients. For functional validation, lung cancer cell lines with knockout of snoRNAs contributing to EPROMET signature were generated using CRISPR/Cas9. Lung cancer cells lacking the corresponding rRNA modifications migrated slower in vitro, failed to grow at a distant site in vivo and were impaired in metastasis. Functionally, it was shown that the modulated ribomethylation signature effected translation of secreted proteins by altered mRNA binding to ribosomes. This study indicates the presence of a ribomethylome-associated phenotype of NSCLC related to metastasis and poor prognosis. Altered ribomethylation affects the ribosome function towards differential expression patterns of secreted proteins. Taken together, an epitranscriptomic pattern of 2’-O-Me is associated with invasion/migration properties of NSCLC cells and with development of metastasis. The ribomethylome may present a suitable biomarker and a potential therapeutic target. Citation Format: Cornelius Pauli, Daniel Heid, Christian Rohde, Nadja Krall, Sylvain Delaunay, Michael Kienhoefer, Christian Tischer, Michael Allgäuer, Maximilian Felix Blank, Fengbiao Zhou, Michael Kardorff, Michael Thomas, Hauke Winter, Sarah Sandmann, Marc Kriegsmann, Marc Schneider, Thomas Muley, Alexander Brobeil, Nicole Bäumer, Sebastian Bäumer, Simon Raffel, Albrecht Stenzinger, Peter Schirmacher, Junyan Lu, Judith Zaugg, Michaela Frye, Carsten Müller-Tidow. A specific ribomethylome pattern in lung cancer is associated with increased risk of metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2763.

Abstract 1807: New strategies to target the pseudokinase receptor PTK7 in the Wnt pathway

Abstract Colorectal cancer (CRC) remains the second cause of death by cancer worldwide and its survival is currently estimated at 60%1. There is therefore a crucial need to identify biomarkers and new targets for therapy. In 90% of CRC, the Wnt/β-catenin pathway is constitutively activated due to mutations of β-catenin, APC (Adenomatous Polyposis Coli) or axin-12. These alterations cause an accumulation of β-catenin and lead to an over-transcription of target genes involved in tumorigenesis3-4. Studies of our team pointed out an overexpression of the Protein Tyrosine Kinase 7 (PTK7) in CRC, an event associated with metastatic development, reduced metastases-free survival, and resistance to chemotherapy. In CRC cells, the pseudokinase PTK7 has pro-metastatic and pro-migratory functions, and thus appears to be a promising new therapeutic target5-6. The role of PTK7 in the Wnt/β-catenin pathway has been demonstrated in several studies7-8. Our group identified β-catenin as a partner of PTK7. We selected a first series of small molecules inhibitors targeting PTK7/β-catenin interaction9. This strategy could represent, in the future, a new therapeutic strategy to inhibit CRC cell growth dependent on the Wnt signaling pathway. However, the compounds identified had weak activity, with an IC50 of around 10-25 mM. We have set up a new method with SYNSIGHT to select more potent chemical inhibitors targeting PTK7/β-catenin in CRC in order to counteract the Wnt/β-catenin signaling pathway deregulation.

Abstract 1394: The CXCL10-CXCR3 axis as Jekyll and Hyde: A regulator of metastasis and immune response in osteosarcoma

Abstract The CXCL10-CXCR3 axis is known to promote tumor growth and metastasis via autocrine signaling, while it can also elicit anti-tumor responses by paracrine signaling. However, its roles are still elusive in osteosarcoma (OS), the most common malignant bone tumor in children. In this study, we utilized in vitro assays, mouse models, and gene expression analysis to characterize the roles of the CXCL10-CXCR3 axis in OS. To understand the autocrine signaling, we performed in vitro phenotypic assays on three OS cell lines with and without CXCL10. The results showed that the chemokine increased AKT phosphorylation and tumor cell migration. Using a CRISPR-based CXCR3 deletion mutant, we demonstrated that the lack of the receptor inhibited OS tumor growth and pulmonary metastasis in an orthotopic xenograft mouse model. The results indicate that the CXCL10-CXCR3 axis is sufficient and necessary to promote aggressive phenotypes in OS via autocrine signaling. Next, using gene expression datasets from two cohorts of OS patients, we showed that high expression of CXCL10 or its cognate receptor CXCR3 was associated with a better prognosis. Since CXCL10 is known to recruit CXCR3+ immune cells to fight against cancer, we further found that the expression of the T cell marker CD3D was associated with a better prognosis. These results suggest that the chemokine may also play a protective role in osteosarcoma by recruiting anti-tumor immune cells via paracrine signaling. Lastly, we have previously reported that a high circulating level of CXCL10 correlates with a poor prognosis in osteosarcoma patients. In this study, we demonstrated that increasing the circulating CXCL10 level in immunodeficient orthotopic xenograft mouse models of OS did not significantly promote the development of pulmonary metastases, suggesting circulating CXCL10 may exert its chemotactic effect mainly on immune cells, not on tumor cells. Taken together, we propose a model that tumor expression of CXCL10 promotes osteosarcoma growth and metastasis development via autocrine signaling. The increase of the local level of CXCL10 attracts CXCR3+ immune cells to the tumor site and promotes anti-tumor function via paracrine signaling. Metastatic cells colonize the lungs and cause tissue damage and inflammation, which increases the production of CXCL10 in the circulation. The higher circulating CXCL10 recruits T cells away from the primary tumor site and indicates the occurrence of metastasis and, hence, correlates with a worse outcome in patients. Our research highlights the importance of understanding the opposite effects of CXCL10 on tumor and immune cells as well as in the tumor microenvironment and circulation. Identification of the mechanistic differences in the CXCL10-CXCR3 signaling between tumor and immune cells will provide a novel therapeutic approach against tumor cells while promoting anti-tumor immune response in OS. Citation Format: Benjamin B. Gyau, Xiang Chen, Junyan Wang, Margaret A. Clement, Angela M. Major, Jun Xu, M. John Hicks, Tsz-Kwong Man. The CXCL10-CXCR3 axis as Jekyll and Hyde: A regulator of metastasis and immune response in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1394.

Abstract 5457: Inflammatory paracrine loops established between metastasis-initiating cells and alveolar epithelium drive interactions between tumor cell subtypes that are essential for osteosarcoma lung colonization

Abstract Introduction: The development of lung metastasis drives the poor outcomes experienced by children and young adults with osteosarcoma. The mechanisms that facilitate metastatic colonization remain poorly understood. We previously determined that IL6 and CXCL8 are two osteosarcoma derived cytokines that are required for metastasis, though roles played by these cytokines have not been identified. Methods: To explore the interactions that drive cytokine expression, the role these factors play in tumor cell trafficking, and the mechanisms that facilitate metastatic niche development, we utilized transwell and co-culture systems together with a panel of metastatic osteosarcoma mouse models that allowed tumor cell manipulation via lentiviruses, CRISPR-based gene editing, and pre-clinical therapeutic evaluation approaches. Results: While metastatic osteosarcoma cells produced small amounts of IL6 and CXCL8 at baseline, lung epithelial cells markedly upregulated IL6/CXCL8 production. Ligand-receptor analysis utilizing single-cell transcriptomic data identified IL1 as an epithelial derived ligand that drives tumor IL6/CXCL8 production. Interestingly, IL6/CXCL8 production was limited to a small subset of hypo-proliferative osteosarcoma cells that have metastasis-initiating capacity. Utilizing CRISPR-mediated ablation of IL1R1 signaling within osteosarcoma cells and pharmacological inhibition with recombinant IL1R antagonist (anakinra), we elucidated that formation of pulmonary lesions in multiple mouse models of metastatic osteosarcoma required IL1 signaling. Recent work from our lab has demonstrated that osteosarcoma metastases are defined by marked phenotypic heterogeneity, though the mechanisms by which metastatic heterogeneity occurred were unclear. We hypothesized that hypo-proliferative metastasis-initiating cells may recruit circulating cells with higher proliferative capacity to establish phenotypic heterogeneity. Transwell migration assays showed that tumor cells induced the chemotactic recruitment of other tumor cells in an IL6/CXCL8-dependent manner. To test this hypothesis in vivo, we injected mice with GFP-tagged osteosarcoma cells, then injected the same mice 14 days later with RFP-labeled tumor cells from the same culture. Lungs harvested 14 days later exhibited RFP-dominant lesions surrounding a small core of GFP-labeled cells. Conclusions: Collectively, these data suggest that cytokines expressed by a subgroup of hypo-proliferative tumor cells upon interaction with lung epithelium drive the trafficking of highly proliferative circulating tumor cells into developing metastatic lesions and that disrupting these signaling networks can prevent metastatic colonization. Citation Format: Amy C. Gross, James B. Reinecke, Amanda Saraf, John Hinckley, Maren Cam, Matthew V. Cannon, Sophia Vatelle, Ryan D. Roberts. Inflammatory paracrine loops established between metastasis-initiating cells and alveolar epithelium drive interactions between tumor cell subtypes that are essential for osteosarcoma lung colonization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5457.

Abstract 1386: CD1d-restricted iNKT cells promote liver metastasis from colon cancer

Abstract The liver is a prominent site for metastasis, yet little is known about the role of liver immunity in antimetastatic defense. Compared to other organs, the liver harbors a unique immune environment characterized by the abundance of innate cell lineages, including CD1d-restricted invariant natural killer T (iNKT) cells. To investigate the influence of iNKT cells on metastasis, we established an orthotopic model of colorectal cancer (CRC) with spontaneous dissemination to the liver. We induce the primary tumor by implanting CRC organoids into the colon mucosa of syngeneic C57BL/6 mice, resulting in hepatic macrometastases within 5 weeks. We observed that liver metastasis hardly occurred in mouse strains lacking iNKT cells (Cd1d−/− and Traj18−/− mice), while the growth of the primary tumor was comparable to that in wild-type mice. These results indicate a tumor-promoting function for hepatic iNKT cells. We uncovered that hepatic iNKT cells respond to disseminating cancer by producing IL-4 and IL-13, two cytokines known to activate hepatic stellate cells (HSCs) into fibrogenic myofibroblasts. Indeed, we saw rapid activation of HSCs and deposition of extracellular matrix upon arrival of cancer cells in the liver of wild-type but not iNKT cell-deficient mice. We propose that hepatic iNKT cells contribute to the formation of a supportive niche for disseminated tumor cells by activating HSCs early in the development of hepatic metastasis. Taken together, our findings highlight an essential tumor-promoting role for iNKT cells during the development of liver metastasis and contribute to our understanding of immune regulation of metastasis. Citation Format: Marc Nater, Giulia Lucchiari, Michael Brügger, Tomas Valenta, Virginia Cecconi, Geo Forni, Stephan Benke, Maries van den Broek. CD1d-restricted iNKT cells promote liver metastasis from colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1386.

Abstract 3749: The evaluation of expression level of Cxcl12 gene in peripheral blood samples of breast cancer patients

Abstract Breast cancer, like many other cancer types, is linked to the activation and overexpression of CXCR4. The overexpression of CXCR4 is associated with factors such as tumor growth, angiogenesis, increased metastasis, and therapeutic resistance. Similarly, CXCL12, a specific ligand for CXCR4, plays a significant role in tumorigenesis processes, including survival, migration, and microenvironmental interactions. The CXCL12/CXCR4 signaling pathway has been found to impact the development and progression of breast cancer, regulating proliferation, motility, and metastasis. Hence, molecules within the CXCL12/CXCR4 signaling pathway hold promise for determining breast cancer prognosis, treatment monitoring, and serving as therapeutic agents. The study, conducted at the Istanbul University Institute of Oncology, obtained ethical approval from the Istanbul Faculty of Medicine Ethics Committee. Genetic materials from 300 breast cancer patients and 150 control subjects underwent standard testing, matched based on crucial parameters. Real-time PCR with the MIC qPCR Cycler was statistically analyzed using GraphPad Prism (p < 0.05). Descriptive statistics were presented for categorical and quantitative variables, while the Kolmogorov-Smirnov test assessed the normal distribution of quantitative variables. Statistical comparisons between groups were performed using the Mann-Whitney U test and the Kruskal-Wallis test. was used for calculations. Notably, among the three genes—LASP1, CXCL12, and CXCR4—LASP1 exhibited the highest mean expression level at 11.64 with a considerable standard deviation of 11.80. In contrast, CXCL12 had a much lower mean expression level at 2.96 and a tighter distribution, and CXCR4 displayed the lowest mean expression level at 0.37 with a standard deviation of 0.74. The analysis of diagnostic groups indicated no significant differences in mean LASP1 and CXCL12 levels, but a significant variance in mean CXCR4 levels (p<0.001). Specifically, CXCR4 expression in group Breast and ovarian cancer was notably lower compared to Breast cancer, Bilateral Breast cancer, and Breast and Other cancer, while group Breast cancer exhibited significantly lower CXCR4 expression compared to groups Bilateral Breast cancer and Breast and Other cancer. However, there was no significant difference in CXCR4 expression between groups of Bilateral Breast cancer and Breast and Other cancer. These findings reveal distinct expression patterns of CXCR4 across diagnostic groups, suggesting potential implications for diagnostic categorization and underlying molecular pathways in breast cancer. Understanding these expression disparities could be crucial in deciphering the molecular intricacies influencing disease progression and treatment responses. Citation Format: Arash Adamnejad Ghafour, Seref Bugra Tuncer. The evaluation of expression level of Cxcl12 gene in peripheral blood samples of breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3749.

Abstract 2762: Spatial proteomics of lung adenocarcinoma mouse models with divergent propensities for metastasis

Abstract Introduction: Lung cancer is the leading cause of cancer deaths worldwide with most deaths attributed to metastasis. Metastases in existing mouse models of lung adenocarcinoma (LUAD) is sporadic and often requires several months of aging. These factors limit these models for basic and pre-clinical research aimed at identifying mechanisms of metastatic disease. We have recently developed two novel mouse models of LUAD that feature constitutively active Kras, loss of Trp53 function and truncated Dicer1 in different cell types. The observed survival and metastatic phenotypes of the models are dependent on the cell type in which the genetic alterations are made. We applied spatial proteomics and metabolomics to investigate molecular drivers underlying the phenotypic differences in our models. Methods and Results: Mouse models were generated by adding mutations in Dicer1, an RNAse III enzyme within the microRNA (miRNA) biosynthesis pathway, to a mouse model of Kras-driven LUAD. For both models, tumorigenesis was induced by conditional expression of an oncogenic allele of Kras, deletion of both alleles of Trp53 and deletion of one allele of Dicer1 in one cell type and the expression of a truncated Dicer1 allele in a different cell type. Mice expressing KrasG12D and deleted Trp53 in club cells without Dicer1 truncation have a reported median survival of 28.6 weeks after tumor induction. We observed accelerated development of LUAD and lymph node metastasis (12.1 weeks) only when we induced tumorigenesis in club cells and truncate Dicer1 in alveolar type II (ATII) cells. Induction of tumorigenesis in ATII cells and truncation of Dicer1 in club cells did not accelerate tumorigenesis or lead to detectable metastasis. Prelminary spatial proteomic analysis revealed significant upregulation of proteins associated with mitochondrial respiratory chain complex I in the tumors of both models which is consistent with processes of bioenergetic adaptation of tumor cells to hypoxic conditions. Gene Ontology annotation term enrichment revealed that the tumors of the two models have distinctive molecular function profiles. Both models show significant disruption of amino acid metabolism but only the model with increased metastatic potential showed apparent disruption in metabolites associated with steroidogenesis. Conclusions: Through cell type specific truncation/deletion of Dicer1 we have generated a mouse model that rapidly develops Kras/Trp53 driven LUAD and metastatic disease. Our findings suggest that tumorigenesis and metastasis are influenced by miRNA-mediated communication between different cell types. Additional studies are underway to link miRNA expression in these models to the results reported here for spatial proteomics and metabolomics. We will continue to develop this model to investigate the molecular mechanisms underlying metastasis. Citation Format: Paige Ramkissoon, Naomi Mitchell-Hutchinson, Julie Wells, Rick Maser, Tim Stodola, Brian Hoffmann, Anne Marchini, Elaine Bechtel, Rosalinda Doty, Carol J. Bult. Spatial proteomics of lung adenocarcinoma mouse models with divergent propensities for metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2762.

Abstract 5481: Spatial multiplex proteins profiling of tumor microenvironment to decipher de novo metastasis in nasopharyngeal carcinoma

Abstract Background: Nasopharyngeal carcinoma (NPC) has a high incidence rate in Southeast Asia, where more than 90% of NPC cases are associated with Epstein-Barr virus (EBV). Although NPC patients are generally sensitive to radiotherapy and chemotherapy, about 20-30% of patients have treatment failure due to the development of distant metastasis, i.e. de novo metastasis. In this study, we utilized GeoMx Digital Spatial Profiler (DSP), a multiplex and high-throughput sequencing platform designed for spatially- and morphologically resolved protein expression profiling to investigate the intra-tumoral and inter-tumoral heterogeneity of tumor microenvironment (TME) and identify the mechanisms underlying distant failure in NPC. Methods: We utilized GeoMx Protein Assays consisting of 147 proteins from 15 functional modules to compare the difference between NPC cases developing distant failure (DF) (n=21) and stage-, age-, gender- and treatment-matched NPC cases without developing distant failure (noDF) (n=15) within five years of treatment. Two fluorescent morphological markers including PanCK and CD45, were used for delineating the structural architecture of the tissues, identifying cell types, and selecting regions of interest (ROIs), followed by sequencing for protein expression quantification. NanoString GeoMx DSP Analysis Suite was used for quality control and data normalization. The NPC TME heterogeneity was further investigated by the 10X Visum platform for spatial transcriptome. The public single-cell RNA sequencing (scRNA-Seq) and bulk RNA sequencing datasets were obtained for the downstream analyses. Results: By analyzing protein expression profiles, the study revealed the intratumoral and intertumoral heterogeneity associated with EBV latent infection in the TME of NPC. Regions with high EBV latent gene expression exhibited a noticeable reduction in T cell infiltration, indicating an "immune cold" phenotype, whereas regions with low EBV latent gene expression displayed heavy T cell infiltration, indicating an "immune hot" phenotype. Moreover, the study identified a panel of autophagic and anti-apoptotic proteins that were significantly upregulated in the cancer cells of NPC cases developing distant failure after treatment. This observation, supported by the single-cell RNA sequencing datasets, further implicated EBV latent infection for the upregulation of autophagic and anti-apoptotic genes. Notably, the study also demonstrated that the genes upregulated in the immune cells in NPC cases with distant failure were associated with poor progression-free survival in an independent NPC cohort. Conclusions: These findings shed light on the crucial role of EBV latent infection in TME heterogeneity and highlight the potential involvement of autophagy and anti-apoptosis in de novo metastasis in NPC. Citation Format: Larry Ka-Yue Chow, Ying Wang, Lanqi Gong, Siqi Xu, Zhaozheng Hou, Xinyuan Guan, Dora Lai-Wan Kwong, Victor Ho-Fun Lee, Wai To ng, Anne Wing-Mui Lee, Zhonghua Liu, Yunfei Xia, Wei Dai. Spatial multiplex proteins profiling of tumor microenvironment to decipher de novo metastasis in nasopharyngeal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5481.

Abstract 4138: Evaluation of breast triple-negative 4T1-derived tumor metastatic development in gender-different mouse

Abstract Background and Objective: Breast cancer in men is a rare and less-studied case, with therapeutic strategies predominantly relying on clinical treatment protocols established for women. To support the clinical treatment concept, Dr. Martin-Martinez's lab observed no differences in the time of orthotopic breast mammary fat pad tumor development, necrosis, or color change of tumor tissue between male and female mice. However, the clinical treatment readout, especially tumor metastasis, is different in men and women, and current models for breast cancer are inadequate due to the absence of metastases. It is necessary to evaluate the development of breast cancer 4T1-derived tumor metastasis in male and female mice. Method and Result: 4T1-Luc breast cancer cells were implanted in male and female Balb/c mice via various routes, including inguinal fat pad injection, tail vein injection, caudal artery injection, portal vein injection, and Intratibial Injection. Illuminance images showed no significant differences in tumor metastatic development between genders for inguinal fat pad, tail vein, and intratibial injections. However, following caudal artery injection, early-stage metastasis differed; male mice developed femoral head metastasis, while female mice developed lung metastasis. In the late stage, male mice displayed lung and femoral bone metastasis, while female mice primarily showed lung metastasis with barely bone metastasis. Conclusion: While both male and female mice showed similar primary breast tumor development, mouse gender affected tumor metastasis differently, particularly when tumor cells went through the caudal artery. Male mice presented earlier femoral head metastasis and less lung metastasis than female mice. Based on this work, sex hormones would affect both hormone-related and nonhormone-related tumor metastasis. To elucidate whether this phenomenon is caused by estrogen or androgen or to test if a drug has any beneficial effects, HD Biosciences provides established tumor metastatic cell-delivering platforms and over 1000 cancer cell lines for target validation and drug efficacy study. Citation Format: Chunhong Shao, Melanie He, Luke Tsung-Huang Tsai. Evaluation of breast triple-negative 4T1-derived tumor metastatic development in gender-different mouse [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4138.

Abstract 4126: The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer

Abstract Endometrial cancer (EC) is the most common gynecologic malignancy. The most common histological type is endometrioid endometrial cancer (EEC). While the majority of patients present with early-stage and low-grade EEC and have an excellent prognosis, a subset develops distant recurrence derived from EEC after initial treatment of the primary. However, the exact mechanism of distant metastasis and recurrence from EEC is still unclear. In addition, the lack of suitable pre-clinical models is a significant barrier to research for distant metastasis and recurrent cancer derived from EEC. Our preclinical EEC model, the ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/fPtenf/f; Mig-6d/dPtend/d), dramatically accelerates the development of EEC compared to single ablation of either gene. The ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/f Ptenf/f; Mig-6d/dPtend/d mice) displayed distant metastases into the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, the Ptend/d mice exhibited endometrial cancer without distant metastases. After hysterectomy of EEC confined to uterus, Mig-6d/dPtend/d mice exhibited recurrent EEC in abdomen and lung. To identify prognostic factors for distant metastatic and recurrent EEC, we performed transcriptomic analysis in endometrial hyperplasia, a precancerous condition, from Ptend/d and Mig-6d/dPtend/d mice. Our transcriptomic analysis identified that cholesterol biosynthesis was the most significantly activated pathway in Mig-6d/dPtend/d mice compared to Ptend/d mice. Statins, also known as HMG-CoA reductase inhibitors, are the most common cholesterol-lowering drugs. We evaluated the effect of atorvastatin on tumorigenesis and recurrence of EEC. Mig-6d/dPtend/d mice treated with atorvastatin displayed significant reduction of tumor size compared to vehicle treated group. For vehicle-treated group, our pathological analysis revealed EEC outside the uterus, therefore EEC had disseminated to involve the ovary, diaphragmatic skeletal muscle, lymph node, and lung. However, EEC was confined to the uterus in the atorvastatin treated group. Furthermore, atorvastatin treatment reduced the rate of recurrent EEC development. This data demonstrated that atorvastatin has a remarkable inhibitory effect on metastasis and recurrence of EEC in Mig-6d/d Ptend/d mice. Our results suggest that statins suppress development of distant metastasis and recurrence in mouse models of EEC with Pten and Mig-6 deficiency by inhibiting cholesterol biosynthesis. Citation Format: Keun Cheon Kim, Jung Yoon Yoo, Russell R Broaddus, Eunhee M Jeong, Mark I Hunter, Tae Hoon Kim, Jae-Wook Jeong. The inhibitory effect of statins on distant metastasis and recurrence of endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4126.

Abstract 1272: Spatial profiling of human colorectal cancer brain metastasis identifies chromosomal instability with adaptive niche cellular reorganization and reprograming

Abstract Brain metastasis in colorectal cancer (mCRC) poses a significant clinical challenge with poor outcomes. Our study, the largest spatial analysis reported to date, aimed to uncover unique cellular and genomic features facilitating metastatic lesion development. Employing spatial transcriptomics on 60 patients' surgical resections, we validated our findings with single-cell RNA sequencing (scRNA-seq), whole-genome sequencing (WGS), and ex vivo functional studies in tumor slice cultures. We obtained spatially distinct gene expression profiles of metastatic tumor cells, tumor microenvironment (TME) and brain parenchymal lineages. Our analysis identified spatially heterogenous upregulation of PI3K, MAPK, EGFR, p53, and TGFβ signaling in metastatic tumor cells. Tumor cells had high levels of chromosomal instability (CIN) marked by recurrent amplifications in chromosomes 6, 7, 17, and 20. WGS from three independent cohorts revealed significantly higher CIN in mCRC brain compared to primary CRC or mCRC from other organs. Spatial neighborhood analysis identified an immune desert phenotype with lack of proximity between lymphocytes and metastatic tumor cells. However, mCRC brain contained abundant plasma cells identifying a unique TME niche feature. Significant proximity between tumor cells and endothelial cells underscored their potential role in tumor seeding and growth. Spatially aware differential expression analysis demonstrated adaptive responses in the brain parenchyma. This included increased Golgi-ER processing and Rho GTPase signaling in neurons and astrocytes adjacent to metastatic tumor cells, respectively. Macrophages were characterized by high expression of pro-fibrogenic genes. Increased SPP1 ligand expression from these macrophages interacted with corresponding receptors on spatially proximal fibroblasts, identifying a key niche reorganization feature that can promote metastatic lesion growth. To evaluate the translational potential of our findings, we examined the effects of perturbating the metastatic niche using scRNA-seq. We established a tumor slice culture from a mCRC brain surgical resection, which maintained all original cell states. Despite elevated signaling pathway activity, metastatic tumor cells were resistant to regorafenib, a multi-receptor tyrosine kinase inhibitor. In contrast, pirfenidone, an anti-fibrotic and anti-inflammatory small molecule, successfully reduced extracellular matrix-associated gene expression programs in fibroblasts in the TME. Our analysis identified distinct properties of mCRC brain that can serve as therapeutic targets, including high levels of chromosomal instability, remodeling of brain parenchyma, lymphocyte evasion, plasma cell abundance and macrophage-fibroblast interactions. Citation Format: Anuja Sathe, Aparajita Khan, Ji In Kang, Rithika Meka, Susan M. Grimes, Andrew S. Luksik, Michael Lim, Claudia Petrisch, Christopher M. Jackson, Hannes Vogel, Melanie Gephart, Summer Han, Hanlee P. Ji. Spatial profiling of human colorectal cancer brain metastasis identifies chromosomal instability with adaptive niche cellular reorganization and reprograming [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1272.

Abstract 2747: Chaperonin-containing TCP-1 promotes the release of exosomes from prostate and breast cancer cells

Abstract Coping with cancer recurrence and assessing metastatic risk are challenges for cancer patients that could be addressed with an effective diagnostic predictor. Exosomes, a subpopulation of extracellular vesicles released by tumor cells, can promote distal metastatic site development and could have promising diagnostic applications. However, the mechanisms controlling exosome secretion by cancer cells remain to be determined, which impedes clinical development. The actions of protein-folding chaperones could facilitate tumor exosome formation, payload loading, and extracellular release. Protein folding complexes link the expression of tumor-promoting oncogenes with the proteins driving oncogenic cancer behavior. Of these, the eukaryotic type II chaperonin, Chaperonin-Containing TCP-1 (CCT), folds many of the oncoproteins (e.g., KRAS, MYC, CDKs, STAT3, etc.) responsible for cancer growth and invasion. CCT is a complex machine composed of eight subunits, each encoded by a unique gene (cct1-8), which folds proteins in an ATP-dependent fashion. We and others showed that CCT is upregulated in breast, lung, and prostate cancer cells as well as neuroblastoma, leading to alterations in apoptosis, migration, cell morphology, and proliferation. Using T47D breast cancer and PC3 and 22rV1 prostate cancer cells, we exogenously expressed or depleted the second subunit of the CCT complex (CCT2). With these cells, we isolated exosomes from culture media by membrane-based affinity binding and examined exosomal RNA and protein content. In exosomes from prostate and breast cancer cells, we found abundant CCT2 subunit mRNA and protein in CD63+ exosomes ranging from 50 to 120 microns in size. When CCT2 was exogenously expressed in breast and prostate cancer cells, CCT2 mRNA and protein were higher in exosomes than other CCT subunits, and CCT2 was randomly distributed throughout the size range of exosomes. Of interest, an increase in CD63+ small exosomes (50-75 microns) was evident in cancer cells exogenously expressing CCT2 compared to mock-transfected and parental controls, suggesting a role for CCT2 in the exosomal secretory pathway. FACS-sorted CD63+ exosomes subjected to mass spectrometry yielded distinct protein content based on CCT2 expression. These findings are the first report of CCT2 driving exosome secretion in cancer cells and suggest that exosomes containing CCT2 RNA and protein are associated with metastatic potential. Exosomal CCT2 thus represents a promising diagnostic indicator for a liquid biopsy approach to monitor cancer recurrence and metastasis. Citation Format: Annette R. Khaled, Lam Truong, Colten Frank, Carolyn Dang, James Velazquez, Priya Gopalan, Sally Litherland. Chaperonin-containing TCP-1 promotes the release of exosomes from prostate and breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2747.