Role Of Tumor Microenvironment Research Articles

Abstract 6350: 2MW4691, a novel CCR8/CTLA-4 bispecific antibody, displays potent anti-tumor efficacy by specifically depeleting tumor-infiltrating Tregs and blocking CTLA-4 signaling on CD8+ T cells

Abstract Background: Regulatory T cells (Tregs) are one of the representative immunosuppressive cells playing a critical role in tumor microenvironment by suppressing anti-tumor immune responses. A great many Treg-depleting therapeutics targeting CTLA-4, CCR8, and CD25 are currently being investigated in clinical trials, and the overwhelming majority of these studies showed systemic toxicity or limited efficacy. Novel modalities favoring tumor-infiltrating Tregs depletion are urgently needed. Here, a CCR8/CTLA-4 bispecific antibody 2MW4691 with inequivalent target arm affinities was developed to specifically deplete tumor-infiltrating Tregs and block CTLA-4 signaling on CD8+ T cells. Methods: Single-cell RNA sequencing data collection and computational analysis were applied to investigate CCR8 and CTLA-4 gene expression profiles in tumor-infiltrating Tregs. 2MW4691 was generated by combining parental bivalent anti-CCR8 and anti-CTLA-4 antibodies with different target arm affinities. CCR8 and CTLA-4 single and double-positive cells were used to evaluate the binding and blocking abilities of 2MW4691. Human FcγRIIIa receptor system, NK cells, and hPBMCs were used to assess the ADCC activity of 2MW4691. hCCR8/hCTLA-4 double transgenic mouse syngeneic models were used to evaluate the anti-tumor efficacy of 2MW4691 in vivo. A repeat dose administration study was performed in cynomolgus monkeys to evaluate the pharmacokinetic and toxicity profiles of 2MW6471. Results: Single-cell RNA sequencing analysis confirmed the co-expression of CCR8 and CTLA-4 in tumor-infiltrating Tregs of NSCLC patients. 2MW4691 was designed as a tetravalency symmetric structure with high binding affinity to CCR8 and low binding affinity to CTLA-4, which resulted in strong ADCC activity towards CCR8 single and CCR8/CTLA4 double-positive cells, but limited ADCC activity towards CTLA-4 single positive cells in cell-based assays. In the staphylococcal enterotoxin B stimulation assay, 2MW4691 promoted T-cell activation, suggesting that it maintained the ability to block CTLA-4-mediated downstream signaling from its parental anti-CTLA-4 antibody. In vivo, 2MW4691 exhibited potent anti-tumor efficacy in hCCR8 or hCTLA4 humanized mice bearing MC38 tumors. Further, the advantage in tumor inhibition of 2MW4691 compared with its parental antibodies was proved in the hCCR8/hCTLA-4 double knock-in mouse model. In the NHP study, 2MW4691 exhibited good pharmacokinetic and safety profiles with negligible impact on peripheral T cells. Conclusion: 2MW4691 demonstrated superior anti-tumor efficacy compared with its parental antibodies in CDX models and favorable tolerability in NHPs. The encouraging preclinical results support further evaluation of 2MW4691 in clinical trials. Citation Format: Cuicui Guo, Xiaodong Dai, Xiumei Xiong, Hongqin Liu, Xiaowei Cen, Hai Wu, Jinchao Zhang, Xun Gui. 2MW4691, a novel CCR8/CTLA-4 bispecific antibody, displays potent anti-tumor efficacy by specifically depeleting tumor-infiltrating Tregs and blocking CTLA-4 signaling on CD8+ T 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 6350.

Abstract PR-011: The role of tumor microenvironment in metastasis and relapses of medulloblastoma using immunocompetent mouse models

Abstract Medulloblastoma (MB) is an embryonal malignant tumor that arises in the cerebellum of infants, children, and adolescents. Despite highly aggressive therapies, including surgery, radiation, and chemotherapy, metastasis remains the primary cause of death in these patients. The tumor microenvironment (TME) has an important role in metastasis and relapse in several cancer types, but it’s role in high-risk MBs (metastatic and relapse) has been understudied. Here, we investigated the process of relapse in an immunocompetent Shh MB mouse model based on somatic mutagenesis induced by Sleeping Beauty (SB)-mediated transposition on a genetically engineered strain carrying a loss-of-function Patched 1 gene (Ptch1) mutation. Lack of one functional copy of the Ptch1 gene predisposes this strain to develop MB. Somatic mutations induced by the transposon increase penetrance of tumor formation in the triple mutant mice carrying the SB transposon system and the Ptch1 mutation. We used this model to study the mechanisms of chemoresistance to cisplatin and cyclophosphamide, that constitute the backbone of the high-dose chemotherapy used to treat patients under the age of 3, who cannot receive craniospinal irradiation. By treating the SB mouse model with surgery followed by high-dose fractionated chemotherapy, we developed a model of MB chemoresistance which is relevant to the infant SHH-MB patient population. While chemotherapy improved mouse survival, only a small number of animals were cured, mirroring the outcome seen in infant patients with Shh MB. Deep sequencing and mapping of transposon-gDNA junctions, along with gene-centric common insertion site analysis (gCIS), revealed that Trp53 transposon insertions are found exclusively at relapse. In the metastatic compartment we observed convergence of gCISes on genes coding for epigenetic regulators, among them a prominent enrichment was found for PRC2 complex genes. RNA-seq analysis on the transcriptome of primary and recurrent tumors indicated that a majority of the differentially expressed genes are associated with inflammatory responses, IL6, and TNF-α/NF-κB signaling. Immunohistochemistry to visualize the expression levels of inflammatory markers: IL-6, CCL2, and F4-80 and spatial targeted multiplexed assays (Geomx) confirmed the increase of immune cells at progression. ChIP-qPCR on cytokine loci revealed binding of PRC2 and deposition of PRC2 mediated repressive histone mark H3K27me3 on the promoter of CCL2 highlighting LOF mutations in PRC2 components as potential epigenetic mechanisms for immune recruitment at progression. Inhibition of immune activation through pharmacological strategies might be a possible therapeutic option for infant SHH-MB. Citation Format: Niusha Khazaei, Ana Castillo Orozco, Wajih Jawhar, Geoffroy Danieau, Kiran Narta, Michael Taylor, Sorana Morrissy, Ana Stuecklin, Livia Garzia. The role of tumor microenvironment in metastasis and relapses of medulloblastoma using immunocompetent mouse models [abstract]. In: Proceedings of the AACR Special Conference on Brain Cancer; 2023 Oct 19-22; Minneapolis, Minnesota. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_1):Abstract nr PR-011.

Abstract A105: Untangling the effect of ascites in shaping high grade serous ovarian cancer progression

Abstract High Grade Serous Ovarian Cancer (HGSOC) is the eighth cause of cancer-related mortality worldwide. Progress in eradicating this disease has been hampered by several factors, including the uncertainty about its tissues of origin, late diagnosis coupled to early dissemination through accumulation of ascitic fluid and extensive inter-patient variability. While being histopathologically homogeneous, HGSOC is characterized by several layers of heterogeneity that require the development of ad hoc research strategies and to focus on specific scales in order to deconvolve HGSOC pathogenetic mechanisms. In this context, our lab has previously shown that HGSOC can be derived both from the distal tract of the fallopian tube (fallopian tube epithelium, FTE) and the ovarian surface epithelium (OSE), with a prognostic impact for the tissue of origin and origin-specific molecular phenotypes, including an immune-suppressive response in the more aggressive OSE-derived subtype (Lo Riso, Villa et al. 2020), pointing at the role of tumor microenvironment in shaping therapeutical response. Moreover, we have also shown the role of ascitic fluid in sustaining the generation of single cell-derived metastatic ovarian cancer spheroids (sMOCS), that enrich for cancer stem-like cells, and allowing to identify a consistent intra-patient variability in response to carboplatin treatment (Velletri, Villa, Cilli, Barzaghi et al. 2022). To understand the specific impact of the tumor microenvironment in shaping HGSOC complexity, here we show an experimental framework aimed at the identification of the downstream effect of ascites in shaping cellular and molecular features of HGSOC. Here we leverage a newly generated single cell transcriptomic atlas, encompassing 1.5 million cells from 79 patients derived from primary tumors, ascites and metastatic samples, to identify specific expression networks activated during the metastatization process. In parallel, we derive from bulk transcriptomic data the set of genes that are induced upon ascitic fluid supplementation in 2D and 3D in vitro models, that are coupled to model-specific phenotypes, including cell proliferation, stemness and invasiveness. These genes are then integrated in the single-cell derived metastasis-specific expression networks to identify the upstream regulators imputable to ascitic fluid exposure. The linked regulators and downstream effectors are then used to identify in the atlas cell populations whose expression landscape is directly affected by ascitic fluid. The identification of such cell populations will allow to highlight cell-to-cell interactions existing between i) different tumor subpopulations; ii) tumor and tumor-associated compartments, in both primary and metastatic samples, that can be ascribed to the presence of ascitic fluid. Moreover, the molecular characterization of these interacting populations will allow to identify novel targets, paving the way to the identification of novel therapeutical avenues for HGSOC patients. Citation Format: Pietro Lo Riso, Carlo Emanuele Villa, Bianca Barzaghi, Marta R. Sallese, Giulia Picco, Alessia Gatto, Ugo Cavallaro, Giuseppe Testa. Untangling the effect of ascites in shaping high grade serous ovarian cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Ovarian Cancer; 2023 Oct 5-7; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(5 Suppl_2):Abstract nr A105.

Targets of tumor microenvironment for potential drug development

AbstractThe tumor microenvironment (TME) is the ecosystem surrounding a tumor, which usually consists of nontumoral cells or components, and molecules they produce and release. The frequent and continuous interplay between tumor cells and the TME strongly affects tumor development, disease progression, metastasis, and responses to therapeutic interventions. As a hub of potential therapeutic targets, the TME has gained appreciable momentum in cancer research. Here we systematically review the progress in targeting the TME as a strategy to develop novel antitumor drugs from the immunological, stromal and extracellular matrix components of the TME, shedding light on its complex synergies with tumor cells. This exploration highlights the transformative potential these elements hold in refining cancer treatment approaches. This thorough examination not only accentuates the TME's multifaceted nature but also positions it as a formidable avenue for propelling forward the paradigms of cancer therapy. This review aims to foster a deeper understanding of the TME's role in oncogenesis and its potential exploitation in advancing targeted, efficacious cancer treatments, marking a significant stride in the realm of cancer research.

Single-cell and Bulk RNA-Seq reveal angiogenic heterogeneity and microenvironmental features to evaluate prognosis and therapeutic response in lung adenocarcinoma.

Angiogenesis stands as a pivotal hallmark in lung adenocarcinoma (LUAD), intricately shaping the tumor microenvironment (TME) and influencing LUAD progression. It emerges as a promising therapeutic target for LUAD, affecting patients' prognosis. However, its role in TME, LUAD prognosis, and its clinical applicability remain shrouded in mystery. We employed integrated single-cell and bulk transcriptome sequencing to unravel the heterogeneity of angiogenesis within LUAD cells. Through "consensus clustering", we delineated distinct angiogenic clusters and deciphered their TME features. "Monocle2" was used to unravel divergent trajectories within malignant cell subpopulations of LUAD. Additionally, regulon submodules and specific cellular communication patterns of cells in different angiogenic states were analyzed by "pyscenic" and "Cellchat" algorithms. The "univariate Cox" and "LASSO" algorithms were applied to build angiogenic prognostic models. Immunohistochemistry (IHC) on clinical samples validated the role of model factors in LUAD angiogenesis. We utilized CTRP 2.0 and PRISM databases for pinpointing sensitive drugs against lung adenocarcinoma. Two clusters for the activation of angiogenesis were identified, with Cluster 1 showing a poor prognosis and a pro-cancerous TME. Three differentiated states of malignant epithelial LUAD cells were identified, which had different degrees of angiogenic activation, were regulated by three different regulon submodules, and had completely different crosstalk from other cells in TME. The experiments validate that SLC2A1 promotes angiogenesis in LUAD. ARS (Angiogenesis related score) had a high prognostic value; low ARSs showed immunotherapy benefits, whereas high ARSs were sensitive to 15 chemotherapeutic agents. The assessment of angiogenic clusters helps to determine the prognostic and TME characteristics of LUAD. Angiogenic prognostic models can be used to assess the prognosis, immunotherapeutic response, and chemotherapeutic drug sensitivity of LUAD.

The RNA m6A writer METTL3 in tumor microenvironment: emerging roles and therapeutic implications.

The tumor microenvironment (TME) is a heterogeneous ecosystem comprising cancer cells, immune cells, stromal cells, and various non-cellular components, all of which play critical roles in controlling tumor progression and response to immunotherapies. Methyltransferase-like 3 (METTL3), the core component of N 6-methyladenosine (m6A) writer, is frequently associated with abnormalities in the m6A epitranscriptome in different cancer types, impacting both cancer cells and the surrounding TME. While the impact of METTL3 on cancer cells has been extensively reviewed, its roles in TME and anti-cancer immunity have not been comprehensively summarized. This review aims to systematically summarize the functions of METTL3 in TME, particularly its effects on tumor-infiltrating immune cells. We also elaborate on the underlying m6A-dependent mechanism. Additionally, we discuss ongoing endeavors towards developing METTL3 inhibitors, as well as the potential of targeting METTL3 to bolster the efficacy of immunotherapy.

The Evolving Paradigm of Immunotherapy in Head-and-neck Squamous Cell Cancers

Immunotherapy (IT) plays a key role in head and neck cancer treatment. The response to IT depends on a multitude of factors that are not yet fully understood, just as the mechanisms of resistance or the role of tumor microenvironment have not been completely defined. For recurrent/metastatic head and neck cancers IT changed the treatment paradigm, both as monotherapy or in combination with chemotherapy, while it is still unclear how and where to place IT in the curative setting. The ineffectiveness of IT is due to multiple reasons, including primary and acquired resistances: several trials are ongoing to assess the efficacy of IT combined with new molecules in different settings, trying to exploit their synergistic role by improving effectiveness and overcoming resistances.

Deciphering head and neck cancer microenvironment: Single-cell and spatial transcriptomics reveals human papillomavirus-associated differences.

Human papillomavirus (HPV) is a major causative factor of head and neck squamous cell carcinoma (HNSCC), and the incidence of HPV- associated HNSCC is increasing. The role of tumor microenvironment in viral infection and metastasis needs to be explored further. We studied the molecular characteristics of primary tumors (PTs) and lymph node metastatic tumors (LNMTs) by stratifying them based on their HPV status. Eight samples for single-cell RNA profiling and six samples for spatial transcriptomics (ST), composed of matched primary tumors (PT) and lymph node metastases (LNMT), were collected from both HPV- negative (HPV- ) and HPV-positive (HPV+ ) patients. Using the 10x Genomics Visium platform, integrative analyses with single-cell RNA sequencing were performed. Intracellular and intercellular alterations were analyzed, and the findings were confirmed using experimental validation and publicly available data set. The HPV+ tissues were composed of a substantial amount of lymphoid cells regardless of the presence or absence of metastasis, whereas the HPV- tissue exhibited remarkable changes in the number of macrophages and plasma cells, particularly in the LNMT. From both single-cell RNA and ST data set, we discovered a central gene, pyruvate kinase muscle isoform 1/2 (PKM2), which is closely associated with the stemness of cancer stem cell-like populations in LNMT of HPV- tissue. The consistent expression was observed in HPV- HNSCC cell line and the knockdown of PKM2 weakened spheroid formation ability. Furthermore, we found an ectopic lymphoid structure morphology and clinical effects of the structure in ST slide of the HPV+ patients and verified their presence in tumor tissue using immunohistochemistry. Finally, the ephrin-A (EPHA2) pathway was detected as important signals in angiogenesis for HPV- patients from single-cell RNA and ST profiles, and knockdown of EPHA2 declined the cell migration. Our study described the distinct cellular composition and molecular alterations in primary and metastatic sites in HNSCC patients based on their HPV status. These results provide insights into HNSCC biology in the context of HPV infection and its potential clinical implications.

MDSC suppresses T cell antitumor immunity in CAC via GPNMB in a MyD88-dependent manner.

Myeloid-derived suppressor cells (MDSCs) played an essential role in tumor microenvironment to suppress host antitumor immunity and help cancer cells escape immune surveillance. However, the molecular mechanism behind tumor evasion mediated by MDSCs is not fully understood. Glycoprotein nonmetastatic melanoma protein B (GPNMB) is considered to associate with tumor initiation, metastasis and angiogenesis. Blocking GPNMB function is a potentially valuable therapy for cancer by eliminating GPNMB+MDSCs. Our previous study has proved that blockage the MyD88 signaling with the MyD88 inhibitor, TJ-M2010-5, may completely prevent the development of CAC in mice, accompanying with downregulation of GPNMB mRNA in the inhibitor-treated mice of CAC. We here focus on the underlying the relationship between GPNMB function and MyD88 signaling pathway activation in MDSCs' antitumor activity in CAC. CAC development in the mouse model is associated with expanded GPNMB+MDSCs by a MyD88-dependent pathway. The GPNMB expression on MDSCs is associated with MyD88 signaling activation. The inhibitory effect of MDSCs on T cell proliferation, activation and antitumor cytotoxicity in CAC is mediated by GPNMB in a MyD8-dependent manner. MyD88 signaling pathway plays an essential role in GPNMB+MDSC-mediated tumor immune escape during CAC development and is a promising focus for revealing the mechanisms of MDSC that facilitate immunosuppression and tumor progression.

TMX family genes and their association with prognosis, immune infiltration, and chemotherapy in human pan-cancer.

The thioredoxin (TMX) system, an important redox system, plays crucial roles in several immune-related diseases. However, there is limited research on the correlation of TMX family gene expression with human pan-cancer prognosis, tumor microenvironment (TME), and immunotherapy. Based on the integration of several bioinformatics analysis methods, we explored the expression levels and prognostic value of TMX family members in pan-cancer and analyzed their association between TME, immune infiltration, stemness scores, and drug sensitivity. Using KEGG enrichment analysis, we explored the potential signaling pathways of their regulation. Additionally, we conducted a transwell assay to verify the relationship between TMX family gene expression and epithelial-mesenchymal transition (EMT) in liver cancer. Expression of the TMX family genes was shown to have an obvious intratumoral heterogeneity. In some cancers, TMX family members expression was also been found to correlate with poor prognosis of patients. Furthermore, TMX family genes may serve important roles in TME. The expression of TMX family genes was found to have a strong correlation with the stromal scores, immune scores, DNAss and RNAss in pan-cancer. Specifically, the expression levels of TMX family genes have been found to be associated with immune subtypes of renal clear cell carcinoma and liver hepatocellular carcinoma. High TMX2 expression promote EMT in liver cancer. The findings of this study may elucidate the biological roles of TMX family genes as potential targets for pan-cancer and also offer valuable insights for further investigating how these genes function in the development and spreading of cancer.

Disruption of LPA-LPAR1 pathway results in lung tumor growth inhibition by downregulating B7-H3 expression in fibroblasts.

Lysophosphatidic acids (LPAs) belong to a class of bioactive lysophospholipids with multiple functions including immunomodulatory roles in tumor microenvironment (TME). LPA exerts its biological effects via its receptors that are highly expressed in fibroblasts among other cell types. As cancer-associated fibroblasts (CAFs) are a key component of the TME, it is important to understand LPA signaling and regulation of receptors in fibroblasts or CAFs and associated regulatory roles on immunomodulation-related molecules. Cluster analysis, immunoblotting, real-time quantitative-PCR, CRISPR-Cas9 gene editing system, immunohistochemical staining, coculture model, and in vivo xenograft model were used to investigate the effects of LPA-LPAR1 on B7-H3 in tumor promotion of CAFs. In this study, we found that LPAR1 and CD276 (B7-H3) were generally highly expressed in fibroblasts with good expression correlation. LPA induced B7-H3 up-expression through LPAR1, and stimulated fibroblasts proliferation that could be inhibited by silencing LPAR1 or B7-H3 as well as small molecule LPAR1 antagonist (Ki16425). Using engineered fibroblasts and non-small cell lung carcinoma (NSCLC) cell lines, subsequent investigations demonstrated that CAFs promoted the proliferation of NSCLC in vitro and in vivo, and such effect could be inhibited by knocking out LPAR1 or B7-H3. The present study provided new insights for roles of LPA in CAFs, which could lead to the development of innovative therapies targeting CAFs in the TME. It is also reasonable to postulate a combinatory approach to treat malignant fibrous tumors (such as NSCLC) with LPAR1 antagonists and B7-H3 targeting therapies.

Targeting integrin α5 in fibroblasts potentiates colorectal cancer response to PD-L1 blockade by affecting extracellular-matrix deposition

BackgroundOne reason patients with cancer cannot benefit from immunotherapy is the lack of immune cell infiltration in tumor tissues. Cancer-associated fibroblasts (CAFs) are emerging as central players in immune regulation...

Abstract A043: CDK8/19-regulated transcriptional reprogramming: a druggable driver of castration-resistant prostate cancer

Abstract Androgen deprivation therapy (ADT) is the mainstay of prostate cancer (PCa) treatment. However, most patients with aggressive PCa become resistant to ADT and develop castration-resistant prostate cancer (CRPC). Newer androgen receptor (AR)-targeting CRPC treatments extend survival by only a few months, and metastatic CRPC (mCRPC) remains an incurable disease. Multiple mechanisms of ADT resistance have been identified, among which non-genetic (transcriptional) mechanisms are prominent, due to the high transcriptomic plasticity of PCa and the role of tumor microenvironment (TME) as a determinant of ADT resistance. PCa progression involves changes in the expression of CDK8 and CDK19, enzymatic components of the cyclin-dependent kinase module (CKM), associated with the transcriptional Mediator complex and implicated in transcriptional reprogramming and immune surveillance. We have investigated the roles of CDK8/19 Mediator kinases in CRPC, through bioinformatic analysis of primary PCa and mCRPC and by analyzing the effects of genetic and pharmacological inhibition of CDK8 and CDK19 on tumor growth and gene expression. CDK8 and CDK19 were found to be differentially regulated by androgen, which downregulates CDK8 and upregulates CDK19. Accordingly, CDK8 is decreased and CDK19 increased in primary PCa, where CDK19 is expressed higher than in any other tissues or tumors. However, both CDK19 and CDK8, as well as the other components of the CKM, are upregulated in mCRPC, concordantly with the changes in AR-mediated transcriptional signaling. Selective Mediator kinase inhibitors did not suppress PCa models driven by canonical AR signaling but inhibited in vivo growth of cell line-based and patient-derived xenograft (PDX) models of CRPC. Genetic inactivation of CDK8 and CDK19 suppressed 22Rv1 CRPC tumors in surgically or chemically castrated (but not intact) male NSG mice, whereas the expression of CDK19 or CDK8 reversed this phenotype. Transcriptomic analysis revealed that Mediator kinase inhibition exerted the strongest effects on gene expression in tumors growing in castrated mice, increasing the transcriptomic effects of castration on most of the genes regulated by CDK8/19, while decreasing its effects on some of the genes implicated in PCa progression. A gene signature reflecting Mediator kinase activity in CRPC xenografts correlated with shorter overall survival among mCRPC patients. Systemic treatment with a CDK8/19 inhibitor also affected stromal gene expression; many of these effects were reproduced by Mediator kinase mutagenesis in tumor cells alone, suggesting that Mediator kinases of tumor cells are involved in shaping the TME. Prolonged (up to 300 days) CDK8/19 inhibition induced not only growth inhibition but also shrinkage of CRPC tumors in nude mice (which contain NK cells that are stimulated by CDK8/19 inhibition) and even produced cures in 18-27% of animals. These results warrant the exploration of CDK8/19 Mediator kinase inhibitors for the treatment of the presently incurable CRPC. Citation Format: Jing Li, Thomas Hilimire, Yueying Liu, Lili Wang, Jiaxin Liang, Balazs Gyorffy, Vitali Sikitzhytski, Hao Ji, Li Zhang, Chen Cheng, Xiaokai Ding, Kendall Kerr, Charles Dowling, Gary Schools, Chang-Uk Lim, Eugenia Broude, George Wilding, Michael Lilly, Igor Roninson, Mengqian Chen. CDK8/19-regulated transcriptional reprogramming: a druggable driver of castration-resistant prostate cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A043.

The role of microbiota in tumorigenesis, progression and treatment of bladder cancer.

For decades, the urinary system was regarded as a sterile environment due to the absence of any bacterial growth in clinical standard urine cultures from healthy individuals. However, a diverse array of microbes colonizes the urinary system in small quantities, exhibiting a variable compositional signature influenced by differences in sex, age, and pathological state. Increasing pieces of evidence suggest microbiota exists in tumor tissue and plays a crucial role in tumor microenvironment based on research in multiple cancer models. Current studies about microbiota and bladder cancer have preliminarily characterized the bladder cancer-related microbiota, but how the microbiota influences the biological behavior of bladder cancer remains unclarified. This review summarizes the characteristics of microbiota in bladder cancer, aims to propose possible mechanisms that microbiota acts in tumorigenesis and progression of bladder cancer based on advances in gut microbiota, and discusses the potential clinical application of microbiota in bladder cancer.

Role of Tumor Microenvironment in Pituitary Neuroendocrine Tumors: New Approaches in Classification, Diagnosis and Therapy.

Adenohypophysal pituitary tumors account for 10-15% of all intracranial tumors, and 25-55% display signs of invasiveness. Nevertheless, oncology still relies on histopathological examination to establish the diagnosis. Considering that the classification of pituitary tumors has changed significantly in recent years, we discuss the definition of aggressive and invasive tumors and the latest molecular criteria used for classifying these entities. The pituitary tumor microenvironment (TME) is essential for neoplastic development and progression. This review aims to reveal the impact of TME characteristics on stratifying these tumors in view of finding appropriate therapeutic approaches. The role of the pituitary tumor microenvironment and its main components, non-tumoral cells and soluble factors, has been addressed. The variable display of different immune cell types, tumor-associated fibroblasts, and folliculostellate cells is discussed in relation to tumor development and aggressiveness. The molecules secreted by both tumoral and non-tumoral cells, such as VEGF, FGF, EGF, IL6, TNFα, and immune checkpoint molecules, contribute to the crosstalk between the tumor and its microenvironment. They could be considered potential biomarkers for diagnosis and the invasiveness of these tumors, together with emerging non-coding RNA molecules. Therefore, assessing this complex network associated with pituitary neuroendocrine tumors could bring a new era in diagnosing and treating this pathology.

Hematologic Neoplasms Associated with Down Syndrome: Cellular and Molecular Heterogeneity of the Diseases.

The molecular basis of Down syndrome (DS) predisposition to leukemia is not fully understood but involves various factors such as chromosomal abnormalities, oncogenic mutations, epigenetic alterations, and changes in selection dynamics. Myeloid leukemia associated with DS (ML-DS) is preceded by a preleukemic phase called transient abnormal myelopoiesis driven by GATA1 gene mutations and progresses to ML-DS via additional mutations in cohesin genes, CTCF, RAS, or JAK/STAT pathway genes. DS-related ALL (ALL-DS) differs from non-DS ALL in terms of cytogenetic subgroups and genetic driver events, and the aberrant expression of CRLF2, JAK2 mutations, and RAS pathway-activating mutations are frequent in ALL-DS. Recent advancements in single-cell multi-omics technologies have provided unprecedented insights into the cellular and molecular heterogeneity of DS-associated hematologic neoplasms. Single-cell RNA sequencing and digital spatial profiling enable the identification of rare cell subpopulations, characterization of clonal evolution dynamics, and exploration of the tumor microenvironment's role. These approaches may help identify new druggable targets and tailor therapeutic interventions based on distinct molecular profiles, ultimately improving patient outcomes with the potential to guide personalized medicine approaches and the development of targeted therapies.

Correlation between synthetic MRI relaxometry and apparent diffusion coefficient in breast cancer subtypes with different neoadjuvant therapy response

BackgroundTo evaluate the correlation between synthetic MRI (syMRI) relaxometry and apparent diffusion coefficient (ADC) maps in different breast cancer subtypes and treatment response subgroups.MethodsTwo hundred sixty-three neoadjuvant therapy (NAT)-treated breast cancer patients with baseline MRI were enrolled. Tumor annotations were obtained by drawing regions of interest (ROIs) along the lesion on T1/T2/PD and ADC maps respectively. Histogram features from T1/T2/PD and ADC maps were respectively calculated, and the correlation between each pair of identical features was analyzed. Meanwhile, features between different NAT treatment response groups were compared, and their discriminatory power was evaluated.ResultsAmong all patients, 20 out of 27 pairs of features weakly correlated (r = – 0.13–0.30). For triple-negative breast cancer (TNBC), features from PD map in the pathological complete response (pCR) group (r = 0.60–0.86) showed higher correlation with ADC than that of the non-pCR group (r = 0.30–0.43), and the mean from the ADC and PD maps in the pCR group strongly correlated (r = 0.86). For HER2-positive, few correlations were found both in the pCR and non-pCR groups. For luminal HER2-negative, T2 map correlated more with ADC than T1 and PD maps. Significant differences were seen in T2 low percentiles and median in the luminal-HER2 negative subtype, yielding moderate AUCs (0.68/0.72/0.71).ConclusionsThe relationship between ADC and PD maps in TNBC may indicate different NAT responses. The no-to-weak correlation between the ADC and syMRI suggests their complementary roles in tumor microenvironment evaluation.Critical relevance statementThe relationship between ADC and PD maps in TNBC may indicate different NAT responses, and the no-to-weak correlation between the ADC and syMRI suggests their complementary roles in tumor microenvironment evaluation.Key points• The relationship between ADC and PD in TNBC indicates different NAT responses.• The no-to-weak correlations between ADC and syMRI complementarily evaluate tumor microenvironment.• T2 low percentiles and median predict NAT response in luminal-HER2-negative subtype.Graphical

Advancing the frontiers of colorectal cancer treatment: harnessing ferroptosis regulation.

In recent years, colorectal cancer incidence and mortality have increased significantly due to poor lifestyle choices. Despite the development of various treatments, their effectiveness against advanced/metastatic colorectal cancer remains unsatisfactory due to drug resistance. However, ferroptosis, a novel iron-dependent cell death process induced by lipid peroxidation and elevated reactive oxygen species (ROS) levels along with reduced activity of the glutathione peroxidase 4 (GPX4) antioxidant enzyme system, shows promise as a therapeutic target for colorectal cancer. This review aims to delve into the regulatory mechanisms of ferroptosis in colorectal cancer, providing valuable insights into potential therapeutic approaches. By targeting ferroptosis, new avenues can be explored for innovative therapies to combat colorectal cancer more effectively. In addition, understanding the molecular pathways involved in ferroptosis may help identify biomarkers for prognosis and treatment response, paving the way for personalized medicine approaches. Furthermore, exploring the interplay between ferroptosis and other cellular processes can uncover combination therapies that enhance treatment efficacy. Investigating the tumor microenvironment's role in regulating ferroptosis may offer strategies to sensitize cancer cells to cell death induction, leading to improved outcomes. Overall, ferroptosis presents a promising avenue for advancing the treatment of colorectal cancer and improving patient outcomes.

Mechanism and Role of Tumor Microenvironment in the Initiation and Progression of Bladder Cancer

Tumor microenvironment (TME) is a huge network, composed by tumor cells, tumor associated stromal cells, immune cells, cytokines and chemokines secreted by these cells, in which various cells communicate with each other. Bladder cancer is characterized of tendency of relapse, progression, metastasis because of the role of TME. With the application and development of new technologies recently, such as tumor bulk RNA-sequencing and single-cell transcriptome sequencing, the composition of TME for bladder cancer is increasingly clear and the complex cell-to-cell communication network is fully duged, which provides a new vision for the therapy of bladder cancer. This paper reviewed and further analysed the research hotspots of cellular components and extracellular matrix components of bladder cancer on the basis of the latest research progress.

Comprehensive analysis of P2Y family genes expression, immune characteristics, and prognosis in pan-cancer

BackgroundP2Y receptors are a family of G protein-coupled receptor genes that have an important function in cancer development and metastasis. However, systematic studies have not been conducted on human tumors. This study attempted to explore the role of P2Y family genes (P2Ys) in pan-cancer. MethodsGene expression and clinical data were downloaded from The Cancer Genome Alas dataset. Gene differential expression, mutation, prognosis, tumor microenvironment (TME) (containing immune cells infiltration, Estimate/immune/stromal scores, immune checkpoints, immune and molecular subtypes, DNA repair genes and methyltransferase), clinical correlation, protein-protein interaction network and functional enrichment analysis were performed. In addition, experiments such as western blots were performed for validation. ResultsEight P2Ys were differentially expressed in most tumor and normal tissues, and their abnormal expression in a variety of cancers could significantly reduce the survival rate of patients. Expression levels of P2Ys, especially P2Y6, P2Y12, P2Y13, P2Y14, were correlated significantly with immune cells, immune checkpoint genes, immune and molecular subtypes and Estimate/immune/stromal scores in a variety of cancers such as uveal melanoma, liver hepatocellular carcinoma, stomach adenocarcinoma, colorectal cancer (CRC), prostate adenocarcinoma, breast invasive carcinoma and uterine corpus endometrial carcinoma (all p < 0.05). P2Ys play an important role in TME and are involved in immune regulation. In addition, enrichment analysis and western blots showed that the levels of P2Y2 and P2Y6 expression regulate the Akt/GSK-3β/β-catenin pathway in CRC, thereby affecting epithelial-to-mesenchymal transition. ConclusionP2Ys may be used as potential pan-cancer biomarkers in prognosis and immunology. They may also be new targets for tumor immunotherapy, which has wide clinical implications.