Promotes Cancer Metastasis Research Articles

MMP‐2 regulates Src activation via repression of the CHK/MATK tumor suppressor in osteosarcoma

AbstractBackgroundDoxorubicin, a first‐line anticancer drug for osteosarcoma treatment, has been the subject of recent research exploring the mechanisms behind its chemoresistance and its ability to enhance cell migration at sublethal concentrations. Matrix metalloproteinase‐2 (MMP‐2), a type IV collagenase and zinc‐dependent endopeptidase, is well‐known for degrading the extracellular matrix and promoting cancer metastasis. Our previous work demonstrated that nuclear MMP‐2 regulates ribosomal RNA transcription via histone clipping, thereby controlling gene expression. Additionally, MMP‐2 activity is regulated by the non‐receptor tyrosine kinase and oncogene, Src, which plays a crucial role in cell adhesion, invasion, and metastasis. Src kinase is primarily regulated by two endogenous inhibitors: C‐terminal Src kinase (Csk) and Csk homologous kinase (CHK/MATK).AimIn this study, we reveal that the MMP‐2 gene acts as an upstream regulator of Src kinase activity by suppressing its endogenous inhibitor, CHK/MATK, in osteosarcoma cells.Methods and ResultsWe show that enhanced osteosarcoma cell migration which is induced by sublethal concentrations of doxorubicin can be overcome by inactivating the MMP‐2 gene or overexpressing CHK/MATK. Our findings highlight the MMP‐2 gene as a promising additional target for combating cancer cell migration and metastasis. This is due to its role in suppressing on the gene and protein expression of the tumor suppressor CHK/MATK in osteosarcoma.ConclusionBy targeting the MMP‐2 gene, we can potentially enhance the effectiveness of doxorubicin treatment and reduce chemoresistance in osteosarcoma.

The β Isoform of Human ATP-Binding Cassette B5 Transporter, ABCB5β, Localizes to the Endoplasmic Reticulum.

ABCB5β is a member of the ABC transporter superfamily cloned from melanocytes. It has been reported as a marker of skin progenitor cells and melanoma stem cells. ABCB5β has also been shown to exert an oncogenic activity and promote cancer metastasis. However, this protein remains poorly characterized. To elucidate its subcellular localization, we tested several anti-ABCB5 antibodies and prepared several tagged ABCB5β cDNA constructs. We then used a combination of immunofluorescence and biochemical analyses to investigate the presence of ABCB5β in different subcellular compartments of HeLa and MelJuSo cell lines. Treatment of the cells with the proteasome inhibitor MG132 showed that part of the population of newly synthesized ABCB5β is degraded by the proteasome system. Interestingly, treatment with SAHA, a molecule that promotes chaperone-assisted folding, largely increased the expression of ABCB5β. Nevertheless, the overall protein distribution in the cells remained similar to that of control conditions; the protein extensively colocalized with the endoplasmic reticulum marker calnexin. Taken together with cell surface biotinylation studies demonstrating that the protein does not reach the plasma membrane (even after SAHA treatment), the data indicate that ABCB5β is a microsomal protein predominantly localized to the ER.

Exosomal long noncoding RNA MLETA1 promotes tumor progression and metastasis by regulating the miR-186-5p/EGFR and miR-497-5p/IGF1R axes in non-small cell lung cancer

BackgroundLung cancer is the most common and deadliest cancer worldwide, and approximately 90% of all lung cancer deaths are caused by tumor metastasis. Tumor-derived exosomes could potentially promote tumor metastasis through the delivery of metastasis-related molecules. However, the function and underlying mechanism of exosomal long noncoding RNA (lncRNA) in lung cancer metastasis remain largely unclear.MethodsCell exosomes were purified from conditioned media by differential ultracentrifugation and observed using transmission electron microscopy, and the size distributions were determined by nanoparticle tracking analysis. Exosomal lncRNA sequencing (lncRNA-seq) was used to identify long noncoding RNAs. Cell migration and invasion were determined by wound-healing assays, two-chamber transwell invasion assays and cell mobility tracking. Mice orthotopically and subcutaneously xenografted with human cancer cells were used to evaluate tumor metastasis in vivo. Western blot, qRT‒PCR, RNA-seq, and dual-luciferase reporter assays were performed to investigate the potential mechanism. The level of exosomal lncRNA in plasma was examined by qRT‒PCR. MS2-tagged RNA affinity purification (MS2-TRAP) assays were performed to verify lncRNA-bound miRNAs.ResultsExosomes derived from highly metastatic lung cancer cells promoted the migration and invasion of lung cancer cells with low metastatic potential. Using lncRNA-seq, we found that a novel lncRNA, lnc-MLETA1, was upregulated in highly metastatic cells and their secreted exosomes. Overexpression of lnc-MLETA1 augmented cell migration and invasion of lung cancer. Conversely, knockdown of lnc-MLETA1 attenuated the motility and metastasis of lung cancer cells. Interestingly, exosome-transmitted lnc-MLETA1 promoted cell motility and metastasis of lung cancer. Reciprocally, targeting lnc-MLETA1 with an LNA suppressed exosome-induced lung cancer cell motility. Mechanistically, lnc-MLETA1 regulated the expression of EGFR and IGF1R by sponging miR-186-5p and miR-497-5p to facilitate cell motility. The clinical datasets revealed that lnc-MLETA1 is upregulated in tumor tissues and predicts survival in lung cancer patients. Importantly, the levels of exosomal lnc-MLETA1 in plasma were positively correlated with metastasis in lung cancer patients.ConclusionsThis study identifies lnc-MLETA1 as a critical exosomal lncRNA that mediates crosstalk in lung cancer cells to promote cancer metastasis and may serve as a prognostic biomarker and potential therapeutic target for lung cancer diagnosis and treatment.

Nicaraven partially attenuates radiation-induced expression of adhesion molecules in the murine lung

Thoracic irradiation has been found to promote cancer metastasis in the lungs, but the relevant mechanism remains unclear. Adhesion and extracellular matrix (ECM) molecules, major components of the tissue microenvironment, play a critical role in cancer metastasis. We have found that nicaraven, a small chemical compound, effectively protects normal tissue (stem) cells against radiation-induced injuries and attenuates cancer metastasis. In this study, we tried to investigate whether nicaraven regulates adhesion and ECM molecules expressions in the irradiated lungs. To find the potential adhesion and ECM molecules are regulated by nicaraven in the irradiated lungs, we collected the lungs from mice 24 h after thorax irradiation with a single dose of 5 Gy X-rays, and then widely evaluated the expression of adhesion and ECM molecules by RT-PCR assay. Our data showed that several adhesion and ECM molecules were up- or down-regulated in the irradiated murine lungs. Interestingly, nicaraven effectively attenuated radiation-enhanced expressions of Itga2 and Pecam1 in the murine lungs. Our study demonstrated that nicaraven suppresses the adhesion and ECM remodeling in the irradiated lungs, which may contribute to attenuate the radiation-induced enhancement of lung metastasis. Further study is warranted to determine how nicaraven regulates the expression of adhesion and ECM molecules and prevents cancer metastasis after irradiation.

C-Reactive Protein Signaling Pathways in Tumor Progression.

Many cancers arise from sites of chronic inflammation, which creates an inflammatory microenvironment surrounding the tumor. Inflammatory substances secreted by cells in the inflammatory environment can induce the proliferation and survival of cancer cells, thereby promoting cancer metastasis and angiogenesis. Therefore, it is important to identify the role of inflammatory factors in cancer progression. This review summarizes the signaling pathways and roles of C-reactive protein (CRP) in various cancer types, including breast, liver, renal, and pancreatic cancer, and the tumor microenvironment. Mounting evidence suggests the role of CRP in breast cancer, particularly in triple-negative breast cancer (TNBC), which is typically associated with a worse prognosis. Increased CRP in the inflammatory environment contributes to enhanced invasiveness and tumor formation in TNBC cells. CRP promotes endothelial cell formation and angiogenesis and contributes to the initiation and progression of atherosclerosis. In pancreatic and kidney cancers, CRP contributes to tumor progression. In liver cancer, CRP regulates inflammatory responses and lipid metabolism. CRP modulates the activity of various signaling molecules in macrophages and monocytes present in the tumor microenvironment, contributing to tumor development, the immune response, and inflammation. In the present review, we overviewed the role of CRP signaling pathways and the association between inflammation and cancer in various types of cancer. Identifying the interactions between CRP signaling pathways and other inflammatory mediators in cancer progression is crucial for understanding the complex relationship between inflammation and cancer.

Exosomal PGAM1 promotes prostate cancer angiogenesis and metastasis by interacting with ACTG1

Tumor-derived exosomes and their contents promote cancer metastasis. Phosphoglycerate mutase 1 (PGAM1) is involved in various cancer-related processes. Nevertheless, the underlying mechanism of exosomal PGAM1 in prostate cancer (PCa) metastasis remains unclear. In this study, we performed in vitro and in vivo to determine the functions of exosomal PGAM1 in the angiogenesis of patients with metastatic PCa. We performed Glutathione-S-transferase pulldown, co-immunoprecipitation, western blotting and gelatin degradation assays to determine the pathway mediating the effect of exosomal PGAM1 in PCa. Our results revealed a significant increase in exosomal PGAM1 levels in the plasma of patients with metastatic PCa compared to patients with non-metastatic PCa. Furthermore, PGAM1 was a key factor initiating PCa cell metastasis by promoting invadopodia formation and could be conveyed by exosomes from PCa cells to human umbilical vein endothelial cells (HUVECs). In addition, exosomal PGAM1 could bind to γ-actin (ACTG1), which promotes podosome formation and neovascular sprouting in HUVECs. In vivo results revealed exosomal PGAM1 enhanced lung metastasis in nude mice injected with PCa cells via the tail vein. In summary, exosomal PGAM1 promotes angiogenesis and could be used as a liquid biopsy marker for PCa metastasis.

ATP-citrate lyase controls endothelial gluco-lipogenic metabolism and vascular inflammation in sepsis-associated organ injury

Sepsis involves endothelial cell (EC) dysfunction, which contributes to multiple organ failure. To improve therapeutic prospects, elucidating molecular mechanisms of vascular dysfunction is of the essence. ATP-citrate lyase (ACLY) directs glucose metabolic fluxes to de novo lipogenesis by generating acetyl-Co-enzyme A (acetyl-CoA), which facilitates transcriptional priming via protein acetylation. It is well illustrated that ACLY participates in promoting cancer metastasis and fatty liver diseases. Its biological functions in ECs during sepsis remain unclear. We found that plasma levels of ACLY were increased in septic patients and were positively correlated with interleukin (IL)-6, soluble E-selectin (sE-selectin), soluble vascular cell adhesion molecule 1 (sVCAM-1), and lactate levels. ACLY inhibition significantly ameliorated lipopolysaccharide challenge-induced EC proinflammatory response in vitro and organ injury in vivo. The metabolomic analysis revealed that ACLY blockade fostered ECs a quiescent status by reducing the levels of glycolytic and lipogenic metabolites. Mechanistically, ACLY promoted forkhead box O1 (FoxO1) and histone H3 acetylation, thereby increasing the transcription of c-Myc (MYC) to facilitate the expression of proinflammatory and gluco-lipogenic genes. Our findings revealed that ACLY promoted EC gluco-lipogenic metabolism and proinflammatory response through acetylation-mediated MYC transcription, suggesting ACLY as the potential therapeutic target for treating sepsis-associated EC dysfunction and organ injury.

The role of extracellular vesicles in non-small-cell lung cancer, the unknowns, and how new approach methodologies can support new knowledge generation in the field

Extracellular vesicles (EVs) are nanosized particles released from most human cell types that contain a variety of cargos responsible for mediating cell-to-cell and organ-to-organ communications. Current knowledge demonstrates that EVs also play critical roles in many aspects of the progression of Non-Small-Cell Lung Cancer (NSCLC). Their roles range from increasing proliferative signalling to inhibiting apoptosis, promoting cancer metastasis, and modulating the tumour microenvironment to support cancer development. However, due to the limited availability of patient samples, intrinsic inter-species differences between human and animal EV biology, and the complex nature of EV interactions in vivo, where multiple cell types are present and several events occur simultaneously, the use of conventional preclinical and clinical models has significantly hindered reaching conclusive results. This review discusses the biological roles that EVs are currently known to play in NSCLC and identifies specific challenges in advancing today's knowledge. It also describes the NSCLC models that have been used to define currently-known EV functions, the limitations associated with their use in this field, and how New Approach Methodologies (NAMs), such as microfluidic platforms, organoids, and spheroids, can be used to overcome these limitations, effectively supporting future exciting discoveries in the NSCLC field and the potential clinical exploitation of EVs.

Expression of pannexin1 in lung cancer brain metastasis and immune microenvironment.

Brain metastases are the most common central nervous system malignancy, and the leading cause of cancer-related deaths. Non-small cell lung carcinomas (NSCLC) comprise the most common cell of origin. Immunotherapy, particularly checkpoint inhibitors, has emerged as the standard of care for many patients with advanced lung cancer. Pannexin1 (PANX1) is a transmembrane glycoprotein that forms large-pore channels and has been reported to promote cancer metastasis. However, the roles of PANX1 in lung cancer brain metastases and tumor immune microenvironment have not been characterized. 42 patient-matched formalin-fixed paraffin-embedded tissue samples from lung carcinomas and the subsequent brain metastases were constructed into three tissue microarrays (TMAs). PANX1 and markers of tumor-infiltrating immune cells (CD3, CD4, CD8, CD68, and TMEM119) were assessed using immunohistochemistry and digital image analysis. The expression of PANX1 was significantly higher in brain metastases than in their paired primary lung carcinoma. The high levels of PANX1 in lung carcinoma cells in the brain inversely correlated with infiltration of peripheral blood-derived macrophages. Our findings highlight the role of PANX1 in the progression of metastatic NSCLC, and the potential therapeutic approach of targeting PANX1 enhances the efficacy of immune checkpoint inhibitors in brain metastasis.

MAP4K4 regulates forces at cell-cell and cell-matrix adhesions to promote collective cell migration.

Collective cell migration is not only important for development and tissue homeostasis but can also promote cancer metastasis. To migrate collectively, cells need to coordinate cellular extensions and retractions, adhesion sites dynamics, and forces generation and transmission. Nevertheless, the regulatory mechanisms coordinating these processes remain elusive. Using A431 carcinoma cells, we identify the kinase MAP4K4 as a central regulator of collective migration. We show that MAP4K4 inactivation blocks the migration of clusters, whereas its overexpression decreases cluster cohesion. MAP4K4 regulates protrusion and retraction dynamics, remodels the actomyosin cytoskeleton, and controls the stability of both cell-cell and cell-substrate adhesion. MAP4K4 promotes focal adhesion disassembly through the phosphorylation of the actin and plasma membrane crosslinker moesin but disassembles adherens junctions through a moesin-independent mechanism. By analyzing traction and intercellular forces, we found that MAP4K4 loss of function leads to a tensional disequilibrium throughout the cell cluster, increasing the traction forces and the tension loading at the cell-cell adhesions. Together, our results indicate that MAP4K4 activity is a key regulator of biomechanical forces at adhesion sites, promoting collective migration.

Disruption of the Clock Component Bmal1 in Mice Promotes Cancer Metastasis through the PAI-1-TGF-β-myoCAF-Dependent Mechanism.

The circadian clock in animals and humans plays crucial roles in multiple physiological processes. Disruption of circadian homeostasis causes detrimental effects. Here, it is demonstrated that the disruption of the circadian rhythm by genetic deletion of mouse brain and muscle ARNT-like 1 (Bmal1) gene, coding for the key clock transcription factor, augments an exacerbated fibrotic phenotype in various tumors. Accretion of cancer-associated fibroblasts (CAFs), especially the alpha smooth muscle actin positive myoCAFs, accelerates tumor growth rates and metastatic potentials. Mechanistically, deletion of Bmal1 abrogates expression of its transcriptionally targeted plasminogen activator inhibitor-1 (PAI-1). Consequently, decreased levels of PAI-1 in the tumor microenvironment instigate plasmin activation through upregulation of tissue plasminogen activator and urokinase plasminogen activator. The activated plasmin converts latent TGF-β into its activated form, which potently induces tumor fibrosis and the transition of CAFs into myoCAFs, the latter promoting cancer metastasis. Pharmacological inhibition of the TGF-β signaling largely ablates the metastatic potentials of colorectal cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. Together, these data provide novel mechanistic insights into disruption of the circadian clock in tumor growth and metastasis. It is reasonably speculated that normalization of the circadian rhythm in patients provides a novel paradigm for cancer therapy.

BRCA1 Insufficiency Induces a Hypersialylated Acidic Tumor Microenvironment That Promotes Metastasis and Immunotherapy Resistance.

BRCA1 deficiency generates an acidic microenvironment to promote cancer metastasis and immunotherapy resistance that can be reversed using a sialyltransferase inhibitor.

A novel cell-based screen identifies chemical entities that reverse the immune-escape phenotype of metastatic tumours.

Genetic and epigenetic events have been implicated in the downregulation of the cellular antigen processing and presentation machinery (APM), which in turn, has been associated with cancer evasion of the immune system. When these essential components are lacking, cancers develop the ability to subvert host immune surveillance allowing cancer cells to become invisible to the immune system and, in turn, promote cancer metastasis. Here we describe and validate the first high-throughput cell-based screening assay to identify chemical extracts and unique chemical entities that reverse the downregulation of APM components in cell lines derived from metastatic tumours. Through the screening of a library of 480 marine invertebrate extracts followed by bioassay-guided fractionation, curcuphenol, a common sesquiterpene phenol derived from turmeric, was identified as the active compound of one of the extracts. We demonstrate that curcuphenol induces the expression of the APM components, TAP-1 and MHC-I molecules, in cell lines derived from both metastatic prostate and lung carcinomas. Turmeric and curcumins that contain curcuphenol have long been utilized not only as a spice in the preparation of food, but also in traditional medicines for treating cancers. The remarkable discovery that a common component of spices can increase the expression of APM components in metastatic tumour cells and, therefore reverse immune-escape mechanisms, provides a rationale for the development of foods and advanced nutraceuticals as therapeutic candidates for harnessing the power of the immune system to recognize and destroy metastatic cancers.

Inhibition of Resveratrol Analogs on Human and Rat 3β-Hydroxysteroid Dehydrogenases: Structure–Activity Relationship and Docking Analysis

Resveratrol and its analogs are phytochemicals. Human 3β-hydroxysteroid dehydrogenase 1 (3β-HSD1) synthesizes steroid hormones for normal pregnancy or promoting cancer metastasis. Whether they inhibit 3β-HSD1 remains unclear. In this study, the inhibitory potency, mode of action, structure-activity relationship, and docking parameters of resveratrol and its analogs on 3β-HSD1 and rat homolog 3β-HSD4 were analyzed. The inhibitory potency of these chemicals on human 3β-HSD1 was 4,4'-dihydroxystilbene (IC50, 3.68 μM) > pinostilbene (8.07 μM) > pinosylvin (10.60 μM) > lunularin (26.84 μM) > resveratrol (30.20 μM) > dihydroresveratrol (>100 μM) = oxyresveratrol (>100 μM) > dihydropinosylvin (ineffective at 100 μM). Resveratrol analogs and metabolites are mixed or competitive inhibitors of human 3β-HSD1. Resveratrol and 4,4'-dihydroxystilbene inhibited progesterone secretion by human JAr cells at ≥1 μM. Resveratrol (IC50, 32.09 μM) and pinosylvin (34.71 μM) significantly inhibited rat placental 3β-HSD4 activity. Docking analysis shows that resveratrol analogs and metabolites bind the steroid-binding sites of human 3β-HSD1 and rat 3β-HSD4 and interact with the catalytic residues Ser125/Thr125 and Tyr155. The negative correlation of LogP and IC50 values for human 3β-HSD1 indicates that lipophilicity of chemicals plays a critical role in the inhibitory effect of chemicals. In conclusion, 4,4'-dihydroxystilbene, pinostilbene, and pinosylvin effectively inhibit human 3β-HSD1 depending on their lipophilicity, thereby acting as potential therapeutic agents.

Small-molecule targeting of GPCR-independent noncanonical G-protein signaling in cancer

Activation of heterotrimeric G-proteins (Gαβγ) by G-protein-coupled receptors (GPCRs) is a quintessential mechanism of cell signaling widely targeted by clinically approved drugs. However, it has become evident that heterotrimeric G-proteins can also be activated via GPCR-independent mechanisms that remain untapped as pharmacological targets. GIV/Girdin has emerged as a prototypical non-GPCR activator of G proteins that promotes cancer metastasis. Here, we introduce IGGi-11, a first-in-class small-molecule inhibitor of noncanonical activation of heterotrimeric G-protein signaling. IGGi-11 binding to G-protein α-subunits (Gαi) specifically disrupted their engagement with GIV/Girdin, thereby blocking noncanonical G-protein signaling in tumor cells and inhibiting proinvasive traits of metastatic cancer cells. In contrast, IGGi-11 did not interfere with canonical G-protein signaling mechanisms triggered by GPCRs. By revealing that small molecules can selectively disable noncanonical mechanisms of G-protein activation dysregulated in disease, these findings warrant the exploration of therapeutic modalities in G-protein signaling that go beyond targeting GPCRs.

MiR-1246 in tumor extracellular vesicles promotes metastasis via increased tumor cell adhesion and endothelial cell barrier destruction.

Tumor blood vessels play a key role in tumor metastasis. We have previously reported that tumor endothelial cells (TECs) exhibit abnormalities compared to normal endothelial cells. However, it is unclear how TECs acquire these abnormalities. Tumor cells secrete extracellular vesicles (EVs) to create a suitable environment for themselves. We have previously identified miR-1246 to be more abundant in high metastatic melanoma EVs than in low metastatic melanoma EVs. In the current study, we focused on miR-1246 as primarily responsible for acquiring abnormalities in TECs and examined whether the alteration of endothelial cell (EC) character by miR-1246 promotes cancer metastasis. We analyzed the effect of miR-1246 in metastatic melanoma, A375SM-EVs, in vivo metastasis. The role of tumor EV-miR-1246 in the adhesion between ECs and tumor cells and the EC barrier was addressed. Changes in the expression of adhesion molecule and endothelial permeability were examined. Intravenous administration of A375SM-EVs induced tumor cell colonization in the lung resulting in lung metastasis. In contrast, miR-1246 knockdown in A375SM decreased lung metastasis in vivo. miR-1246 transfection in ECs increased the expression of adhesion molecule ICAM-1 via activation of STAT3, followed by increased tumor cell adhesion to ECs. Furthermore, the expression of VE-Cadherin was downregulated in miR-1246 overexpressed EC. A375SM-EV treatment enhanced endothelial permeability. VE-Cadherin was validated as the potential target gene of miR-1246 via the target gene prediction database and 3' UTR assay. miR-1246 in high metastatic tumor EVs promotes lung metastasis by inducing the adhesion of tumor cells to ECs and destroying the EC barrier.

Abstract 2948: A humanized therapeutic antibody against S100A4 as a novel immune modulator and an inhibitor of cancer metastasis

Abstract Widespread cancer metastasis still contributes to ~ 90% of cancer-related deaths, and limited progress has been made in treating the metastatic disease. S100A4 is a highly conserved protein and has been demonstrated to promote cancer metastasis and stemness in multiple cancer types. Furthermore, our recent single cell RNA-sequencing analysis of cancer and stromal cells in human gliomas showed that S100A4 is expressed in both cancer and immune cells to promotes immune suppressive tumor microenvironment. Significantly deleting S100A4 function in stromal cells alone was sufficient to reverse the immune phenotypes of glioma associated T cells and myeloid cells, and resulted in significantly extend survival of two different mouse glioma models. Consistently, higher S100A4 expression is also associated with poor outcomes in many cancer types. Together these observations suggest that S100A4 is a promising therapeutic target for multiple cancer types, and we developed and characterized a blocking antibody against human S100A4. We have screened 114 monoclonal antibodies against S100A4 using S100A4-induced chicken neurite outgrowth ex vivo as a functional assay. Seven of the 114 monoclonals showed significant suppressive activity ex vivo and were selected for further analysis for their in vivo activity. We chose two well-characterized breast cancer metastasis models for in vivo screening: MMTV-PyMT spontaneous and 4T1 orthotopic transplantation tumor models. One of the clones, 4-11, showed the most consistent and dramatic lung metastasis suppressive activity in both models. To identify the potential mechanisms of action since the blocking antibody is anticipated to only affect soluble S100A4 function, we focused on potential immune modulatory effect, based on our own study and those of others. We performed flow cytometry to analyze the immune phenotypes in blood, bone marrow, spleen, breast tumor, and lung metastases. In S100A4-11 treated mice, circulating monocytes (CD11b+Ly6gloLy6chi) and tumor-associated CD163+ macrophage frequencies were significantly decreased in both models. In addition, circulating CD4+ T cells and neutrophils (CD11b+Ly6g+Ly6cint) frequencies were also decreased in the 4T1 model. Others have shown that myeloid-derived suppressive cells (MDSC: CD11b+, Ly6gloLy6chi,IAIE-) play an important role in cancer metastasis. Our result suggests that soluble S100A4 protein promotes MDSC polarization or survival in the tumor, peripheral blood, and metastatic lung tissues. These findings strongly suggest that S100A4-11 could be used to block metastasis. We are currently testing the humanized S1004-11 antibody in preparation for clinical studies with this novel immune modulator. Citation Format: Jia-Shiun Leu, Hui Deng, Han Nhat Tran, Jose Maria Salazar, Jose A. Maldonado, Carlo D. Cristobal, Xiong Wei, Hyun-Kyoung Lee, Zhiqiang An, Ningyan Zhang, Kyuson Yun. A humanized therapeutic antibody against S100A4 as a novel immune modulator and an inhibitor of cancer metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2948.

Abstract 1461: C-terminally phosphorylated p27 modulates chromatin remodeling in breast cancer

Abstract Breast Cancer (BC) is the leading cause of cancer-related death in women. Transcriptional deregulation is a frequent characteristic of cancers. Chromatin remodeling determines the accessibility of the chromatin through dynamic modification of chromatin architecture, and thereby regulates gene expression. Alteration in chromatin remodeling is associated with cancer. Therefore, a greater understanding of chromatin remodeling and its role in tumorigenesis could provide a significant cornerstone to develop more effective therapeutic strategies. p27 is an integral regulator of the cell cycle. It plays a dual role in tumorigenesis. p27 acts as a tumor suppressor to restrain the cell cycle, but upon C-terminal phosphorylation at T157 and T198 by PI3K activated kinases, it acts as an oncogene to promote cancer metastasis. We previously showed that p27pT157pT198 (p27pTpT) acts as a transcriptional co-regulator of cJun. Our new data now indicate that p27pTpT also binds to and transcriptionally co-regulates STAT3 to drive cancer stem cell gene programs. We also found that p27 is widely recruited to consensus motifs shared by many other transcription factors, suggesting a broader role in transcriptional regulation. Here we investigated if p27pTpT regulates transcriptional programs in BC through modulating chromatin accessibility. ATACseq was carried out in 231 cells, 231 with overexpression of a cell cycle-defective phosphomimetic p27 (231p27CK-DD), and in 1883 cells with high phospho-activated p27 levels, and 1833 with p27 knockdown and analyzed together with our prior p27 ChIPseq. p27pTpT increased ATAC-seq signals at the promoter of a sub-set of STAT3 target genes, where p27 ChIPseq and ATACseq signals overlapped. These genes are upregulated in 231p27CK-DD and in 1833 compared to 231. Thus, p27 appears to potentiate a more open chromatin state at these binding sites to modulate gene expression. p27 and STAT3 co-occupy at the promoters of the STAT3 target genes including MYC, IL6, and VEGFA, in which p27 knockdown decreased STAT3 recruitment to these sites. Using ENCODE p300 and CBP ChIP-seq data, we found potential co-localization of histone acetyltransferase (HAT), CBP and p300, with p27 and STAT3 on MYC, IL6, and VEGFA promoters. Thus, p27 might recruit HATs to the chromatin to increase chromatin accessibility through H3K27 acetylation (H3K27ac). ChIP-qPCR assays validated that p27, STAT3 and CBP recruitment to the MYC promoter was greater in p27-activated 231p27CK-DD and 1833 lines than in 231, and decreased upon p27 depletion in 1833. Notably, ChIP assays also showed CBP recruitment increased H3K27ac at this site. These data support a model in which p27 enrichment to the promoter of a subset of STAT3 target genes increases both CBP and STAT3 recruitment, to increase chromatin accessibility through H3K27ac and upregulate their expression. This work revealed a novel genome-wide action of p27 in chromatin remodeling. Citation Format: Seyedeh Fatemeh Razavipour, Hyunho Yoon, Miyoung Shin, Alec McIntosh, Dekuang Zhao, Amir Bagheri, Derek Van Booven, Chunling Yi, Joyce Slingerland. C-terminally phosphorylated p27 modulates chromatin remodeling in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1461.

Three-dimensional and single-cell sequencing of liver cancer reveals comprehensive host-virus interactions in HBV infection.

Hepatitis B virus (HBV) infection is a major risk factor for chronic liver diseases and liver cancer (mainly hepatocellular carcinoma, HCC), while the underlying mechanisms and host-virus interactions are still largely elusive. We applied HiC sequencing to HepG2 (HBV-) and HepG2-2.2.15 (HBV+) cell lines and combined them with public HCC single-cell RNA-seq data, HCC bulk RNA-seq data, and both genomic and epigenomic ChIP-seq data to reveal potential disease mechanisms of HBV infection and host-virus interactions reflected by 3D genome organization. We found that HBV enhanced overall proximal chromatin interactions (CIs) of liver cells and primarily affected regional CIs on chromosomes 13, 14, 17, and 22. Interestingly, HBV altered the boundaries of many topologically associating domains (TADs), and genes nearby these boundaries showed functional enrichment in cell adhesion which may promote cancer metastasis. Moreover, A/B compartment analysis revealed dramatic changes on chromosomes 9, 13 and 21, with more B compartments (inactive or closed) shifting to A compartments (active or open). The A-to-B regions (closing) harbored enhancers enriched in the regulation of inflammatory responses, whereas B-to-A regions (opening) were enriched for transposable elements (TE). Furthermore, we identified large HBV-induced structural variations (SVs) that disrupted tumor suppressors, NLGN4Y and PROS1. Finally, we examined differentially expressed genes and TEs in single hepatocytes with or without HBV infection, by using single-cell RNA-seq data. Consistent with our HiC sequencing findings, two upregulated genes that promote HBV replication, HNF4A and NR5A2, were located in regions with HBV-enhanced CIs, and five TEs were located in HBV-activated regions. Therefore, HBV may promote liver diseases by affecting the human 3D genome structure. Our work promotes mechanistic understanding of HBV infection and host-virus interactions related to liver diseases that affect billions of people worldwide. Our findings may also have implications for novel immunotherapeutic strategies targeting HBV infection.

ANO1 reprograms cholesterol metabolism and the tumor microenvironment to promote cancer metastasis.

Tumor metastasis is a complex process. A better understanding of the mechanistic underpinnings of the metastatic cascade could uncover approaches to better prevent and target metastases. Here, we integrated transcriptomic profiling in primary esophageal squamous cell carcinoma (ESCC) and matched lymph node metastatic tissues and genome-wide CRISPR/Cas9 functional screening to identify the key drivers of cancer metastasis. Anoctamin 1 (ANO1) expression was found to be elevated in primary tumors and further increased in metastatic tissues. High expression of ANO1 was associated with poor patient survival, and ANO1 overexpression promoted cancer invasion and metastasis. Mechanistically, ANO1 inactivated the LXR pathway and increased intracellular cholesterol accumulation by interacting with JUN to repress the transcription of cholesterol hydroxylase, CYP27A1. In a paracrine manner, interleukin 1β (IL-1β) secreted from ANO1-expressing ESCC cancer cells activated NFκB signaling in fibroblasts to stimulate production of the chemokine CCL1, which in turn enhanced invasion of ESCC cancer cells. Furthermore, molecular docking and in silico screening of 1,500,000 small molecules identified K786-4469 as a lead compound that targeted ANO1 and suppressed cancer metastasis in vitro and in vivo. Overall, these findings uncover a non-canonical function of ANO1 in regulating cholesterol metabolism and fibroblast function, revealing ANO1 as a potential prognostic biomarker and therapeutic target for metastatic ESCC.