A highly selective humanized DDR1 mAb reverses immune exclusion by disrupting collagen fiber alignment in breast cancer

Targeted degradation of DDR1 by proteolytic targeting chimera reverses immune exclusion for tumor immunotherapy

The formation of immune exclusion microenvironment restricts the infiltration of immune cells into the core of tumors. The extracellular domain of the discoidin domain receptor tyrosine kinase 1 (DDR1) protein plays a pivotal role in this process by aligning collagen fibers to remodel the extracellular matrix (ECM), thereby excluding immune cells. Targeted degradation of DDR1 represents a promising approach to suppress the catalytic functions of the protein and remodel the extracellular matrix of DDR1-related tumors. Here, we report the discovery of a selective DDR1 degrader (DP 1), using the proteolysis targeting chimera (PROTAC) approach. Compound DP 1 exhibited potent DDR1 degradation ability with DC50 values reaching nanomolar range across various cell lines. The degradation of DDR1 effectively blocked the downstream signaling pathways, leading to further inhibition of tumor cell migration and invasion. More importantly, the in vivo studies highlighted the therapeutic potential of DDR1 degradation, indicated by the administration of DP 1 could facilitate the infiltration of immune cells into the tumor core which was associated with enhanced tumor apoptosis. In summary, we report a novel DDR1-targeting degrader with efficacious anti-tumor activity and excellent safety profile. Our studies offer a new perspective for cancer immunotherapy by targeting the immune-exclusion microenvironment.

Epithelial-mesenchymal transition orchestrates tumor microenvironment: current perceptions and challenges

The epithelial-mesenchymal transition (EMT) is a critical process in cancer progression, facilitating tumor cells to develop invasive traits and augmenting their migratory capabilities. EMT is primed by tumor microenvironment (TME)-derived signals, whereupon cancer cells undergoing EMT in turn remodel the TME, thereby modulating tumor progression and therapeutic response. This review discusses the mechanisms by which EMT coordinates TME dynamics, including secretion of soluble factors, direct cell contact, release of exosomes and enzymes, as well as metabolic reprogramming. Recent evidence also indicates that cells undergoing EMT may differentiate into cancer-associated fibroblasts, thereby establishing themselves as functional constituents of the TME. Elucidating the relationship between EMT and the TME offers novel perspectives for therapeutic strategies to enhance cancer treatment efficacy. Although EMT-directed therapies present significant therapeutic potential, the current lack of effective targeting approaches-attributable to EMT complexity and its microenvironmental context dependency-underscores the necessity for mechanistic investigations and translational clinical validation.

Emerging strategies and translational advancements of DDR1 in oncology

Discoidin domain receptor 1 (DDR1) has emerged as a promising therapeutic target in oncology due to its unique role in tumor-stroma interactions and its involvement in key signaling pathways that drive cancer progression. DDR1 is homologous to the transmembrane receptor tyrosine kinase (RTK) family and uniquely requires binding to collagen for its activation. It regulates several cellular processes related to tumor cell proliferation, metabolism, migration, stromal remodeling, and epithelial-mesenchymal transition (EMT), ultimately influencing patient survival. Dysregulation of DDR1 may contribute to cancer progression, neurodegenerative diseases, fibrotic conditions, and atherosclerosis. Moreover, DDR1 has been shown to affect a wide variety of cancers, including lung, breast, stomach, colon, ovarian, and pancreatic cancers, underscoring its potential as a therapeutic target. Various small-molecule tyrosine kinase inhibitors aimed at DDR1 have been developed and have demonstrated significant effectiveness in reducing tumor growth. This review focuses on the structure, function, and mechanism of DDR1, as well as its involvement in cancer progression. Additionally, it examines the development and therapeutic potential of DDR1 inhibitors, offering a comprehensive overview of their application in cancer treatment. By synthesizing current knowledge, this article provides valuable insights to guide future research and innovation in targeting DDR1 for clinical therapeutic advancement.

The role of various collagen types in tumor biology: a review

Collagen comprises approximately 30% of the body's protein content and is essential for maintaining the structural integrity, support, and strength of the skin, muscles, bones, and connective tissues. Recent research has further elucidated its role in various aspects of tumor biology, including tumorigenesis, invasion, migration, drug resistance, and recurrence. Furthermore, collagen is involved in prognostic assessments, the evaluation of therapeutic efficacy, immunoregulation, and the identification of potential treatment targets in oncology. This review examines a range of tumor types, including lung, gastric, breast, melanoma, and colorectal cancers, among others. Our objective is to differentiate these tumors based on the specific types of collagen present and to analyze the roles of various collagen types in tumor development, progression, prognosis, and their potential as therapeutic targets.

Collagen remodeling-mediated signaling pathways and their impact on tumor therapy

In addition to their traditional roles in maintaining tissue morphology and organ development, emerging evidence suggests that collagen (COL) remodeling-referring to dynamic changes in the quantity, stiffness, arrangements, cleavage states, and homo-/hetero-trimerization of COLs-serves as a key signaling mechanism that governs tumor growth and metastasis. COL receptors act as switches, linking various forms of COL remodeling to different cell types during cancer progression, including cancer cells, immune cells, and cancer-associated fibroblasts. In this review, we summarize recent findings on the signaling pathways mediated by COL arrangement, cleavage, and trimerization states (both homo- and hetero-), as well as the roles of the primary COL receptors-integrin, DDR1/2, LAIR-1/2, MRC2, and GPVI-in cancer progression. We also discuss the latest therapeutic strategies targeting COL fragments, cancer-associated fibroblasts, and COL receptors, including integrins, DDR1/2, and LAIR1/2. Understanding the pathways modulated by COL remodeling and COL receptors in various pathological contexts will pave the way for developing new precision therapies.

Explanatory review on DDR inhibitors: their biological activity, synthetic route, and structure-activity relationship

Discoidin domain receptors (DDR) are categorized under tyrosine kinase receptors (RTKs) and play a crucial role in various etiological conditions such as cancer, fibrosis, atherosclerosis, osteoarthritis, and inflammatory diseases. The structural domain rearrangement of DDR1 and DDR2 involved six domains of interest namely N-terminal DS, DS-like, intracellular juxtamembrane, transmembrane juxtamembrane, extracellular juxtamembrane intracellular kinase domain, and the tail portion contains small C-tail linkage. DDR has not been explored to a wide extent to be declared as a prime target for any particular pathological condition. Very few scientific data are available so there is a need to study the receptors and their inhibitors. Still, there did not exist FDA-approved small molecules targeting DDR1 and DDR2 receptors so there is an urgent need to develop potent small molecules. Further, the structural features and ligand specificities encourage the researchers to be fascinated about the DDR and explore them for the mentioned biological conditions. Therefore, in the last few years, researchers have been involved in investigating the potent DDR inhibitors. The current review provides an outlook on the anatomy and physiology of DDR, focusing on the structural features of DDR receptors and the mechanism of signaling pathways. We have also compiled the evolutionary development status of DDR inhibitors according to their chemical classes, biological activity, selectivity, and structure-activity relationship. From biological activity analysis, it was revealed that compounds 64a (selectivity: DDR1) and 103a (selectivity: DDR2) were the most potent candidates with excellent activity with IC50 values of 4.67 and 3.2 nM, respectively.

DDR1 in pancreatic adenocarcinoma: unraveling the mechanisms of immune exclusion

BACKGROUND

Pancreatic adenocarcinoma (PAAD) is a deadly cancer marked by extensive collagen deposition and limited response to immunotherapy. Discoidin domain receptor1 (DDR1), part of the transmembrane receptor tyrosine kinase family, is linked to inflammation regulation and immune cell infiltration. However, its role in controlling cytokines and chemokines in the microenvironment of PAAD is still unclear.

METHODS

Initially, RNA sequencing data from TCGA were utilized to investigate the expression of DDR1. Subsequently, the relationship between DDR1 and immune infiltration was examined through Gene Ontology (GO) and Gene Set Enrichment Analysis (GSEA) analysis, in conjunction with ssGSEA Immunoanalysis. Lastly, the effect of DDR1 on the malignant characteristics of PAAD cells was examined through in vitro experimentation, employing various techniques such as the CCK8 assay, colony formation assay and reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

RESULTS

The research revealed a notable increase in the expression level of DDR1 in PAAD. Subsequent analysis indicated a correlation between the differential expression of DDR1 with chemokines and immune infiltration. Additionally, cellular experiments demonstrated that the downregulation of DDR1 led to enhanced expression of chemokines CCL4, CCL5 and CXCL10.

CONCLUSION

DDR1 is linked to tumor immune infiltration, and the knockout of DDR1 results in the upregulation of chemokines CCL4, CCL5 and CXCL10 in Pan02 PAAD cells.

The role of DDR1 in cancer and the progress of its selective inhibitors

Discoidin domain receptor 1 (DDR1) is a member of the receptor tyrosine kinase superfamily, which mainly activates downstream signaling pathways through binding to collagen. The abnormal expression of DDR1 is closely related to the occurrence and development of various tumors, and it is one of the potential targets for molecular targeted therapy. At present, specific antibodies and selective small molecule inhibitors against DDR1 have been approved for Phase I clinical trials. In this review, we summarized the effects of DDR1 on tumor cell proliferation, survival, migration, invasion, energy metabolism and tumor microenvironment, and combed the research progress of selective DDR1 small molecule inhibitors in the field of anti-tumor. It is hoped that more DDR1 inhibitors with excellent performance will be developed to provide more treatment options for tumor patients.

The Multifaced Role of Collagen in Cancer Development and Progression

Collagen is a crucial protein in the extracellular matrix (ECM) essential for preserving tissue architecture and supporting crucial cellular functions like proliferation and differentiation. There are twenty-eight identified types of collagen, which are further divided into different subgroups. This protein plays a critical role in regulating tissue homeostasis. However, in solid tumors, the balance can be disrupted, due to an abundance of collagen in the tumor microenvironment, which significantly affects tumor growth, cell invasion, and metastasis. It is important to investigate the specific types of collagens in cancer ECM and their distinct roles in tumor progression to comprehend their unique contribution to tumor behavior. The diverse pathophysiological functions of different collagen types in cancers illustrate collagen's dual roles, offering potential therapeutic options and serving as prognostic markers.

Antibody-drug conjugates targeting DDR1 as a novel strategy for treatment of breast cancer

Antibody-drug conjugates (ADCs) have emerged as a novel class of targeted cancer therapies and been successfully applied in the treatment of breast cancer (BC). Discoidin domain receptor 1 (DDR1) is a single transmembrane receptor tyrosine kinase and has been identified as a possible target for cancer. In this study, we explored the potential of an anti-DDR1 ADC, named T4H11-DM4, for the treatment of DDR1-positive BC. We demonstrated that high protein expression and RNA expression of DDR1 in BC tissues. In vitro, T4H11-DM4 was potently cytotoxic to DDR1-expressing BC cells, with IC50 in the nanomolar range. In mice BC xenograft models, T4H11-DM4 dramatically eliminated BC tumours, without observable toxicity. Taken together, our findings demonstrated that DDR1 can serve as a promising therapeutic target for BC.

The novel immune landscape of immune-checkpoint blockade in EBV-associated malignancies

The Epstein-Barr virus (EBV) is a ubiquitous gamma-herpesvirus and a class 1 carcinogen that is closely associated with a series of malignant lymphomas and epithelial cell carcinomas. Although these EBV-related cancers may exhibit different features in clinical symptoms and anatomical sites, they all have a characteristic immune-suppressed tumor immune microenvironment (TIME) that is tightly correlated with an abundance of tumor-infiltrating lymphocytes (TILs) that primarily result from the EBV infection. Overwhelming evidence indicates that an upregulation of immune-checkpoint molecules is a powerful strategy employed by the EBV to escape immune surveillance. While previous studies have mainly focused on the therapeutic effects of PD-1 and CTLA-4 blockades in treating EBV-associated tumors, several novel inhibitory receptors (e.g., CD47, LAG-3, TIM-3, VISTA, and DDR1) have recently been identified as potential targets for treating EBV-associated malignancies (EBVaMs). This review retrospectively summarizes the biological mechanisms used for immune checkpoint evasion in EBV-associated tumors. Its purpose is to update our current knowledge concerning the underlying mechanisms by which an immune checkpoint blockade triggers host antitumor immunity against EBVaMs. Additionally, this review may help investigators to more fully understand the correlation between EBV infection and tumor development and subsequently develop novel therapeutic strategies.

Comprehensive analysis of single-cell transcriptomics and genetic factors reveals the mechanisms and preventive strategies for the progression from pulmonary fibrosis to lung cancer

BACKGROUND

Pulmonary fibrosis (PF) leads to excessive deposition of fibrous connective tissue in the lungs, increasing the risk of lung cancer due to the enhanced activity of fibroblasts (FBs). Fibroblast-mediated collagen fiber deposition creates a tumor-like microenvironment, laying the foundation for tumorigenesis. Clinically, numerous cases of lung cancer induced by pulmonary fibrosis have been observed. In recent years, the study of nucleotide point mutations, which provide more detailed insights than gene expression, has made significant advancements, offering new perspectives for clinical research.

METHODS

We initially employed Mendelian randomization to ascertain that the initial stage of lung cancer induced by PF belongs to small cell lung cancer (SCLC). Subsequently, pulmonary neuroendocrine cells (PNECs) were identified by using pseudo-time series analysis as cell clusters with carcinogenic potential. We categorized FBs into four groups according to their cellular metabolism, and then analyzed the cellular communication between FBs and PNECs, as well as changes in intracellular pathways of PNECs. Additionally, we examined the characteristic genome of FBs which is significantly associated with PF and investigated the impact of FBs on immune cells in the PF microenvironment. Finally, we explored strategies for preventing the progression from PF to lung cancer.

RESULTS

The genetic features of cells with carcinogenic potential in PF tissues were revealed, characterized by upregulation of Achaete-Scute Family BHLH Transcription Factor 1 (ASCL1), Homeobox B2 (HOXB2), Teashirt Zinc Finger Homeobox 2 (TSHZ2), Insulinoma-associated 1 (INSM1), and reduced activity of RE1 Silencing Transcription Factor (REST). FBs characterized by high glycolysis and low tricarboxylic acid (TCA) cycling played a key role in the progression of PF. The microenvironment of PF resembles the tumor microenvironment, providing a conducive immunosuppressive environment for the occurrence of cancer cells. In dendritic cells, rs9265808 is a susceptibility locus for progression from pulmonary fibrosis to lung cancer, mutations at this locus increase the expression of Complement Factor B (CFB), and excessive activation of the complement pathway is a crucial factor leading to lung cancer development in patients with pulmonary fibrosis. Ensuring adequate nutritional supply and physical function is one of the effective measures to prevent progression from pulmonary fibrosis to lung cancer.

CONCLUSION

CFB promotes lung cancer occurrence by inducing the accumulation and polarization of a large number of monocytes/macrophages in the lungs, driving disease progression by reducing the physical fitness of patients with pulmonary fibrosis.

Exploring the Mechanisms and Preventive Strategies for the Progression from Idiopathic Pulmonary Fibrosis to Lung Cancer: Insights from Transcriptomics and Genetic Factors

Background: Idiopathic pulmonary fibrosis (IPF) leads to excessive fibrous tissue in the lungs, increasing the risk of lung cancer (LC) due to heightened fibroblast activity. Advances in nucleotide point mutation studies offer insights into fibrosis-to-cancer transitions. Methods: A two-sample Mendelian randomization (TSMR) approach was used to explore the causal relationship between IPF and LC. A weighted gene co-expression network analysis (WGCNA) identified shared gene modules related to immunogenic cell death (ICD) from transcriptomic datasets. Machine learning selected key genes, and a multi-layer perceptron (MLP) model was developed for IPF prediction and diagnosis. SMR and PheWAS were used to assess the expression of key genes concerning IPF risk. The impact of core genes on immune cells in the IPF microenvironment was explored, and in vivo experiments were conducted to examine the progression from IPF to LC. Results: The TSMR approach indicated a genetic predisposition for IPF progressing to LC. The predictive model, which includes eight ICD key genes, demonstrated a strong predictive capability (AUC = 0.839). The SMR analysis revealed that the elevated expression of MS4A4A was associated with an increased risk of IPF (OR = 1.275, 95% CI: 1.029-1.579; p = 0.026). The PheWAS did not identify any significant traits linked to MS4A4A expression. The rs9265808 locus in MS4A4A was identified as a susceptibility site for the progression of IPF to LC, with mutations potentially reprogramming lung neutrophils and increasing the LC risk. In vivo studies suggested MS4A4A as a promising therapeutic target. Conclusions: A causal link between IPF and LC was established, an effective prediction model was developed, and MS4A4A was highlighted as a therapeutic target to prevent IPF from progressing to LC.

The extracellular matrix in solid tumor immunotherapy

The extracellular matrix (ECM) of solid tumors impacts the antitumor activities of CD8+ T and natural killer (NK) cells in a variety of ways. Cell motility is restricted by the tumor ECM which creates physical barriers. The tumor ECM directly alter the phenotypes and functions of cytotoxic lymphocytes, and indirectly influences immunological synapse-mediated interactions between cytotoxic lymphocytes and cancer cells. Therefore, strategies to improve solid tumor immunotherapy should be established by considering complex ternary interactions between cytotoxic lymphocytes, cancer cells, and the tumor ECM. Novel bioengineering tools approximating key characteristics of the tumor ECM, such as in vitro reconstituted 3D ECMs and microfluidics are valuable from a fundamental study viewpoint and from a translational perspective, aiming to enable systematic screening approaches.

Multiple aspects of matrix stiffness in cancer progression

The biophysical and biomechanical properties of the extracellular matrix (ECM) are crucial in the processes of cell differentiation and proliferation. However, it is unclear to what extent tumor cells are influenced by biomechanical and biophysical changes of the surrounding microenvironment and how this response varies between different tumor forms, and over the course of tumor progression. The entire ensemble of genes encoding the ECM associated proteins is called matrisome. In cancer, the ECM evolves to become highly dysregulated, rigid, and fibrotic, serving both pro-tumorigenic and anti-tumorigenic roles. Tumor desmoplasia is characterized by a dramatic increase of α-smooth muscle actin expressing fibroblast and the deposition of hard ECM containing collagen, fibronectin, proteoglycans, and hyaluronic acid and is common in many solid tumors. In this review, we described the role of inflammation and inflammatory cytokines, in desmoplastic matrix remodeling, tumor state transition driven by microenvironment forces and the signaling pathways in mechanotransduction as potential targeted therapies, focusing on the impact of qualitative and quantitative variations of the ECM on the regulation of tumor development, hypothesizing the presence of matrisome drivers, acting alongside the cell-intrinsic oncogenic drivers, in some stages of neoplastic progression and in some tumor contexts, such as pancreatic carcinoma, breast cancer, lung cancer and mesothelioma.

Glycosylation in the tumor immune response: the bitter side of sweetness

Glycosylation is the most structurally diverse form of post-translational modification (PTM) of proteins that affects a myriad of cellular processes. As a pivotal regulator of protein homeostasis, glycosylation notably impacts the function of proteins, spanning from protein localization and stability to protein-protein interactions. Aberrant glycosylation is a hallmark of cancer, and extensive studies have revealed the multifaceted roles of glycosylation in tumor growth, migration, invasion and immune escape Over the past decade, glycosylation has emerged as an immune regulator in the tumor microenvironment (TME). Here, we summarize the intricate interplay between glycosylation and the immune system documented in recent literature, which orchestrates the regulation of the tumor immune response through endogenous lectins, immune checkpoints and the extracellular matrix (ECM) in the TME. In addition, we discuss the latest progress in glycan-based cancer immunotherapy. This review provides a basic understanding of glycosylation in the tumor immune response and a theoretical framework for tumor immunotherapy.

DDR1-targeted therapies: current limitations and future potential

Discoidin domain receptor (DDR)-1 has a crucial role in regulating vital processes, including cell differentiation, proliferation, adhesion, migration, invasion, and matrix remodeling. Overexpression or activation of DDR1 in various pathological scenarios makes it a potential therapeutic target for the treatment of cancer, fibrosis, atherosclerosis, and neuropsychiatric, psychiatric, and neurodegenerative disorders. In this review, we summarize current therapeutic approaches targeting DDR1 from a medicinal chemistry perspective. Furthermore, we analyze factors other than issues of low selectivity and risk of resistance, contributing to the infrequent success of DDR1 inhibitors. The complex interplay between DDR1 and the extracellular matrix (ECM) necessitates additional validation, given that DDR1 might exhibit complex and synergistic interactions with other signaling molecules during ECM regulation. The mechanisms involved in DDR1 regulation in cancer and inflammation-related diseases also remain unknown.

The Tumor Stroma of Squamous Cell Carcinoma: A Complex Environment That Fuels Cancer Progression

The tumor microenvironment (TME), a complex assembly of cellular and extracellular matrix (ECM) components, plays a crucial role in driving tumor progression, shaping treatment responses, and influencing metastasis. This narrative review focuses on the cutaneous squamous cell carcinoma (cSCC) tumor stroma, highlighting its key constituents and their dynamic contributions. We examine how significant changes within the cSCC ECM-specifically, alterations in fibronectin, hyaluronic acid, laminins, proteoglycans, and collagens-promote cancer progression, metastasis, and drug resistance. The cellular composition of the cSCC TME is also explored, detailing the intricate interplay of cancer-associated fibroblasts (CAFs), mesenchymal stem cells (MSCs), endothelial cells, pericytes, adipocytes, and various immune cell populations. These diverse players modulate tumor development, angiogenesis, and immune responses. Finally, we emphasize the TME's potential as a therapeutic target. Emerging strategies discussed in this review include harnessing the immune system (adoptive cell transfer, checkpoint blockade), hindering tumor angiogenesis, disrupting CAF activity, and manipulating ECM components. These approaches underscore the vital role that deciphering TME interactions plays in advancing cSCC therapy. Further research illuminating these complex relationships will uncover new avenues for developing more effective treatments for cSCC.

Novel insights into the role of Discoidin domain receptor 2 (DDR2) in cancer progression: a new avenue of therapeutic intervention

Discoidin domain receptors (DDRs), including DDR1 and DDR2, are a unique class of receptor tyrosine kinases (RTKs) activated by collagens at the cell-matrix boundary interface. The peculiar mode of activation makes DDRs as key cellular sensors of microenvironmental changes, with a critical role in all physiological and pathological processes governed by collagen remodeling. DDRs are widely expressed in fetal and adult tissues, and experimental and clinical evidence has shown that their expression is deregulated in cancer. Strong findings supporting the role of collagens in tumor progression and metastasis have led to renewed interest in DDRs.  However, despite an increasing number of studies, DDR biology remains poorly understood, particularly the less studied DDR2, whose involvement in cancer progression mechanisms is undoubted. Thus, the understanding of a wider range of DDR2 functions and related molecular mechanisms is expected. To date, several lines of evidence support DDR2 as a promising target in cancer therapy. Its involvement in key functions in the tumor microenvironment makes DDR2 inhibition particularly attractive to achieve simultaneous targeting of tumor and stromal cells, and tumor regression, which is beneficial for improving the response to different types of anti-cancer therapies, including chemo- and immunotherapy. This review summarizes current research on DDR2, focusing on its role in cancer progression through its involvement in tumor and stromal cell functions, and discusses findings that support the rationale for future development of direct clinical strategies targeting DDR2.

Expression of the Discoidin Domain Receptor Family Depended on Glucose and Their High Expression in Arterial Tissues in the Rat Model of Type 2 Diabetes

The active form of discoidin domain receptors (DDRs) is expressed in cell surface and regulated post-translationally by glucose. The DDR2 and DDR1 transfected in HEK293 cells were expressed mainly in their active forms with sizes of 130 and 120 kDa, respectively. DDRs were observed predominantly as 100 kDa proteins in glucose-depleted culture conditions. However, transfection of endothelial growth factor receptor (EGFR) in HEK293 cells resulted in the expression of only one form regardless of glucose concentration. Vascular smooth muscle cells, HT1080s, and MDA-MB-231 cancer cells expressed DDRs in their active forms in high glucose concentrations, which did not occur with EGFR. In diabetic rats, DDRs were expressed at high levels in arterial tissue but EGFR was not highly expressed. Taken together, these results suggest that DDRs expression depends on glucose concentration it may cooperate in the development of atherosclerosis and kidney fibroblasts, promoting nephropathy in diabetic rats.

Altered Treg Infiltration after Discoidin Domain Receptor 1 (DDR1) Inhibition and Knockout Promotes Tumor Growth in Lung Adenocarcinoma

Lung cancer is the leading cause of cancer-related death worldwide. Discoidin domain receptor 1 (DDR1), a tyrosine kinase receptor, has been associated with poor prognosis in patients with non-small cell lung cancer (NSCLC). However, its role in tumorigenesis remains poorly understood. This work aimed to explore the impact of DDR1 expression on immune cell infiltration in lung adenocarcinoma. Pharmacological inhibition and knockout of DDR1 were used in an immunocompetent mouse model of KRAS/p53-driven lung adenocarcinoma (LUAD). Tumor cells were engrafted subcutaneously, after which tumors were harvested for investigation of immune cell composition via flow cytometry. The Cancer Genome Atlas (TCGA) cohort was used to perform gene expression analysis of 509 patients with LUAD. Pharmacological inhibition and knockout of DDR1 increased the tumor burden, with DDR1 knockout tumors showing a decrease in CD8+ cytotoxic T cells and an increase in CD4+ helper T cells and regulatory T cells. TCGA analysis revealed that low-DDR1-expressing tumors showed higher FoxP3 (regulatory T-cell marker) expression than high-DDR1-expressing tumors. Our study showed that under certain conditions, the inhibition of DDR1, a potential therapeutic target in cancer treatment, might have negative effects, such as inducing a pro-tumorigenic tumor microenvironment. As such, further investigations are necessary.

Recent progress of mechanosensitive mechanism on breast cancer

The mechanical environment is important for tumorigenesis and progression. Tumor cells can sense mechanical signals by mechanosensitive receptors, and these mechanical signals can be converted to biochemical signals to regulate cell behaviors, such as cell differentiation, proliferation, migration, apoptosis, and drug resistance. Here, we summarized the effects of the mechanical microenvironment on breast cancer cell activity, and mechanotransduction mechanism from cellular microenvironment to cell membrane, and finally to the nucleus, and also relative mechanosensitive proteins, ion channels, and signaling pathways were elaborated, therefore the mechanical signal could be transduced to biochemical or molecular signal. Meanwhile, the mechanical models commonly used for biomechanics study in vitro and some quantitative descriptions were listed. It provided an essential theoretical basis for the occurrence and development of mechanosensitive breast cancer, and also some potential drug targets were proposed to treat such disease.

Regulation of tumor immunity and immunotherapy by the tumor collagen extracellular matrix

It has been known for decades that the tumor extracellular matrix (ECM) is dysfunctional leading to loss of tissue architecture and promotion of tumor growth. The altered ECM and tumor fibrogenesis leads to tissue stiffness that act as a physical barrier to immune cell infiltration into the tumor microenvironment (TME). It is becoming increasingly clear that the ECM plays important roles in tumor immune responses. A growing body of data now indicates that ECM components also play a more active role in immune regulation when dysregulated ECM components act as ligands to interact with receptors on immune cells to inhibit immune cell subpopulations in the TME. In addition, immunotherapies such as checkpoint inhibitors that are approved to treat cancer are often hindered by ECM changes. In this review we highlight the ways by which ECM alterations affect and regulate immunity in cancer. More specifically, how collagens and major ECM components, suppress immunity in the complex TME. Finally, we will review how our increased understanding of immune and immunotherapy regulation by the ECM is leading towards novel disruptive strategies to overcome immune suppression.