Colony-Stimulating Factor 1 Receptor (CSF1R) Activates AKT/mTOR Signaling and Promotes T-Cell Lymphoma Viability

The molecular determinants of microglial developmental dynamics

Microglia constitute the largest population of parenchymal macrophages in the brain and are considered a unique subset of central nervous system glial cells owing to their extra-embryonic origins in the yolk sac. During development, microglial progenitors readily proliferate and eventually colonize the entire brain. In this Review, we highlight the origins of microglial progenitors and their entry routes into the brain and discuss the various molecular and non-molecular determinants of their fate, which may inform their specific functions. Specifically, we explore recently identified mechanisms that regulate microglial colonization of the brain, including the availability of space, and describe how the expansion of highly proliferative microglial progenitors facilitates the occupation of the microglial niche. Finally, we shed light on the factors involved in establishing microglial identity in the brain.

Colony-stimulating factor-1 receptor inhibition combined with paclitaxel exerts effective antitumor effects in the treatment of ovarian cancer

Ovarian cancer is the tumor with the highest mortality among gynecological malignancies. Studies have confirmed that paclitaxel chemoresistance is associated with increased infiltration of tumor-associated macrophages (TAMs) in the microenvironment. Colony-stimulating factor 1 (CSF-1) receptor (CSF-1R) plays a key role in regulating the number and differentiation of macrophages in certain solid tumors. There are few reports on the effects of targeted inhibition of CSF-1R in combination with chemotherapy on ovarian cancer and the tumor microenvironment. Here, we explored the antitumor efficacy and possible mechanisms of the CSF - 1R inhibitor pexidartinib (PLX3397) when combined with the first-line chemotherapeutic agent paclitaxel in the treatment of ovarian cancer. We found that CSF-1R is highly expressed in ovarian cancer cells and correlates with poor prognosis. Treatment by PLX3397 in combination with paclitaxel significantly inhibited the growth of ovarian cancer both in vitro and in vivo. Blockade of CSF-1R altered the macrophage phenotype and reprogrammed the immunosuppressive cell population in the tumor microenvironment.

Macrophage colony-stimulating factor and its role in the tumor microenvironment: novel therapeutic avenues and mechanistic insights

The tumor microenvironment is a complex ecosystem where various cellular and molecular interactions shape the course of cancer progression. Macrophage colony-stimulating factor (M-CSF) plays a pivotal role in this context. This study delves into the biological properties and functions of M-CSF in regulating tumor-associated macrophages (TAMs) and its role in modulating host immune responses. Through the specific binding to its receptor colony-stimulating factor 1 receptor (CSF-1R), M-CSF orchestrates a cascade of downstream signaling pathways to modulate macrophage activation, polarization, and proliferation. Furthermore, M-CSF extends its influence to other immune cell populations, including dendritic cells. Notably, the heightened expression of M-CSF within the tumor microenvironment is often associated with dismal patient prognoses. Therefore, a comprehensive investigation into the roles of M-CSF in tumor growth advances our comprehension of tumor development mechanisms and unveils promising novel strategies and approaches for cancer treatment.

CSF1R inhibition reprograms tumor-associated macrophages to potentiate anti-PD-1 therapy efficacy against colorectal cancer

PD-1 blockade therapy has made great breakthroughs in treatment of multiple solid tumors. However, patients with microsatellite-stable (MSS) colorectal cancer (CRC) respond poorly to anti-PD-1 immunotherapy. Although CRC patients with microstatellite instability (MSI) or microsatellite instability-high (MSI-H) can benefit from PD-1 blockade therapy, there are still some problems such as tumor recurrence. Tumor-associated macrophages (TAMs), most abundant immune components in tumor microenvironment (TME), largely limit the therapeutic efficacy of anti-PD-1 against CRC. The CSF1/CSF1R pathway plays a key role in regulating macrophage polarization, and blocking CSF1R signaling transduction may be a potential strategy to effectively reprogram macrophages and remodel TME. Here, we found that increasing expression of CSF1R in macrophages predicted poor prognosis in CRC cohort. Furthermore, we discovered a novel potent CSF1R inhibitor, PXB17, which significantly reprogramed M2 macrophages to M1 phenotype. Mechanically, PXB17 significantly blocked activation of PI3K/AKT/mTORC1 signaling, resulting in inhibition of cholesterol biosynthesis. Results from 3D co-culture system suggested that PXB17-repolarized macrophages could induce infiltration of CD8+ T lymphocytes in tumors and improve the immunosuppressive microenvironment. In vivo, PXB17 significantly halted CRC growth, with a stronger effect than PLX3397. In particular, PXB17 potently enhanced therapeutic activity of PD-1 mAb in CT-26 (MSS) model and prevented tumor recurrence in MC-38 (MSI-H) model by promoting formation of long-term memory immunity. Our study opens a new avenue for CSF1R in tumor innate and adaptive anti-tumor immunomodulatory activity and suggests that PXB17 is a promising immunotherapy molecule for enhancing the efficacy of PD-1 mAb or reducing tumor recurrence of CRC.

Exploring the Link between Inflammatory Biomarkers and Head and Neck Cancer: Understanding the Impact of Smoking as a Cancer-Predisposing Factor

Head and neck cancer (HNC) is associated with significant morbidity globally, with smoking recognized as a key risk factor. This study investigates the interplay between smoking and inflammatory biomarkers in HNC development. The study involved 50 HNC patients, divided into smoking and non-smoking groups, and a control group of 30 healthy individuals. Serum levels of 48 cytokines, chemokines, growth factors, and other inflammatory markers were meticulously assessed. Significant differences in the levels of an extensive panel of inflammatory markers were observed between the patient groups and healthy controls. Elevated macrophage colony-stimulating factor (M-CSF) in both HNC groups implicated increased activity in pathways known for immunomodulation, proliferation, and angiogenesis during HNC cancerogenesis. In contrast, non-smokers with HNC demonstrated higher levels of interleukin 10 (IL-10) and interleukin 15 (IL-15), suggesting a more robust immune response. Platelet-derived growth factor BB (PDGF-BB) levels were particularly high in smokers with HNC. Smoking seems to alter the levels of crucial biomarkers in HNC, potentially affecting disease progression and responses to treatment. The data indicate that smokers may experience a more aggressive cancer phenotype, while non-smokers maintain a profile suggestive of a more active and effective immune response against HNC.

Tumor-Microenvironment-Activatable Nanoparticle Mediating Immunogene Therapy and M2 Macrophage-Targeted Inhibitor for Synergistic Cancer Immunotherapy

Immunotherapy has achieved prominent clinical efficacy in combating cancer and has recently become a mainstream treatment strategy. However, achieving broad efficacy with a single modality is challenging, and the heterogeneity of the tumor microenvironment (TME) restricts the accuracy and effectiveness of immunotherapy strategies for tumors. Herein, a TME-responsive targeted nanoparticle to enhance antitumor immunity and reverse immune escape by codelivering interleukin-12 (IL-12) expressing gene and colony-stimulating factor-1 receptor (CSF-1R) inhibitor PLX3397 (PLX) is presented. The introduction of disulfide bonds and cyclo(Arg-Gly-Asp-d-Phe-Lys) (cRGD) peptides conferred reduction reactivity and tumor targeting to the nanoparticles, respectively. It is hypothesized that activating host immunity by the local expression of IL-12, while modulating the tumor-associated macrophages (TAM) function through blocking CSF-1/CSF-1R signaling, could constitute a feasible approach for cancer immunotherapy. The fabricated functional nanoparticle successfully ameliorated the TME by stimulating the proliferation and activation of T lymphocytes, promoting the repolarization of TAMs, reducing myeloid-derived suppressor cells (MDSCs), and promoting the maturation of dendritic cells (DC) as well as the secretion of antitumor cytokines, which efficiently suppressed tumor growth and metastasis. Finally, substantial changes in the TME were deciphered by single-cell analysis including infiltration of different cells, transcriptional states, secretory signaling and cell-cell communications. These findings provide a promising combinatorial immunotherapy strategy through immunomodulatory nanoparticles.

CSF-1R in Cancer: More than a Myeloid Cell Receptor

Colony-stimulating factor 1 receptor (CFS-1R) is a myeloid receptor with a crucial role in monocyte survival and differentiation. Its overexpression is associated with aggressive tumors characterized by an immunosuppressive microenvironment and poor prognosis. CSF-1R ligands, IL-34 and M-CSF, are produced by many cells in the tumor microenvironment (TME), suggesting a key role for the receptor in the crosstalk between tumor, immune and stromal cells in the TME. Recently, CSF-1R expression was reported in the cell membrane of the cancer cells of different solid tumors, capturing the interest of various research groups interested in investigating the role of this receptor in non-myeloid cells. This review summarizes the current data available on the expression and activity of CSF-1R in different tumor types. Notably, CSF-1R+ cancer cells have been shown to produce CSF-1R ligands, indicating that CSF-1R signaling is positively regulated in an autocrine manner in cancer cells. Recent research demonstrated that CSF-1R signaling enhances cell transformation by supporting tumor cell proliferation, invasion, stemness and drug resistance. In addition, this review covers recent therapeutic strategies, including monoclonal antibodies and small-molecule inhibitors, targeting the CSF-1R and designed to block the pro-oncogenic role of CSF-1R in cancer cells.

Successful anti-tumor effects with two novel bifunctional chemotherapeutic compounds that combine a LAT1 substrate with cytotoxic moieties in aggressive T-cell lymphomas

T-cell lymphomas are aggressive neoplasms characterized by poor responses to current chemotherapeutic agents. Expression of the l-type amino acid transporter 1 (LAT 1, SLC7A5) allows for the expansion of healthy T-cell counterparts, and upregulation of LAT1 has been reported in precursor T-cell acute leukemia. Therefore, the expression of LAT1 was evaluated in a cohort of cutaneous and peripheral T-cell lymphomas. The findings demonstrated that LAT1 is upregulated in aggressive variants and absent in low-grade or indolent disease such as mycosis fungoides. In addition, upregulated LAT1 expression was seen in a large proportion of aggressive peripheral T-cell lymphomas, including peripheral T-cell lymphoma not otherwise specific (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL). The anti-tumor effects of two novel non-cleavable and bifunctional compounds, QBS10072S and QBS10096S, that combine a potent cytotoxic chemotherapeutic domain (tertiary N-bis(2-chloroethyl)amine) with the structural features of a selective LAT1 substrate (aromatic β-amino acid) were tested in vitro and in vivo in T-cell lymphoma cell lines. The findings demonstrated decreased survival of T-cell lymphoma lines with both compounds. Overall, the results demonstrate that LAT1 is a valuable biomarker for aggressive T-cell lymphoma counterparts and QBS10072S and QBS10096S are successful therapeutic options for these aggressive diseases.

Ultra-Deep Sequencing Reveals the Mutational Landscape of Classical Hodgkin Lymphoma

The malignant Hodgkin and Reed Sternberg (HRS) cells of classical Hodgkin lymphoma (cHL) are scarce in affected lymph nodes, creating a challenge to detect driver somatic mutations. As an alternative to cell purification techniques, we hypothesized that ultra-deep exome sequencing would allow genomic study of HRS cells, thereby streamlining analysis and avoiding technical pitfalls. To test this, 31 cHL tumor/normal pairs were exome sequenced to approximately 1,000× median depth of coverage. An orthogonal error-corrected sequencing approach verified >95% of the discovered mutations. We identified mutations in genes novel to cHL including: CDH5 and PCDH7, novel stop gain mutations in IL4R, and a novel pattern of recurrent mutations in pathways regulating Hippo signaling. As a further application of our exome sequencing, we attempted to identify expressed somatic single-nucleotide variants (SNV) in single-nuclei RNA sequencing (snRNA-seq) data generated from a patient in our cohort. Our snRNA analysis identified a clear cluster of cells containing a somatic SNV identified in our deep exome data. This cluster has differentially expressed genes that are consistent with genes known to be dysregulated in HRS cells (e.g., PIM1 and PIM3). The cluster also contains cells with an expanded B-cell clonotype further supporting a malignant phenotype. This study provides proof-of-principle that ultra-deep exome sequencing can be utilized to identify recurrent mutations in HRS cells and demonstrates the feasibility of snRNA-seq in the context of cHL. These studies provide the foundation for the further analysis of genomic variants in large cohorts of patients with cHL.

SIGNIFICANCE

Our data demonstrate the utility of ultra-deep exome sequencing in uncovering somatic variants in Hodgkin lymphoma, creating new opportunities to define the genes that are recurrently mutated in this disease. We also show for the first time the successful application of snRNA-seq in Hodgkin lymphoma and describe the expression profile of a putative cluster of HRS cells in a single patient.

Survival and Enrichment Analysis of Epithelial-Mesenchymal Transition Genes in Bladder Urothelial Carcinoma

The escalating prevalence of bladder cancer, particularly urothelial carcinoma, necessitates innovative approaches for prognosis and therapy. This study delves into the significance of genes related to epithelial-mesenchymal transition (EMT), a process inherently linked to carcinogenesis and comparatively better studied in other cancers. We examined 1184 EMT-related gene expression levels in bladder urothelial cancer cases through the TCGA dataset. Genes shown to be differentially expressed in relation to survival underwent further network and enrichment analysis to uncover how they might shape disease outcomes. Our in silico analysis revealed a subset of 32 genes, including those significantly represented in biological pathways such as VEGF signaling and bacterium response. In addition, these genes interact with genes involved in the JAK-STAT signaling pathway. Additionally, some of those 32 genes have been linked to immunomodulators such as chemokines CCL15 and CCL18, as well as to various immune cell infiltrates. Our findings highlight the prognostic utility of various EMT-related genes and identify possible modulators of their effect on survival, allowing for further targeted wet lab research and possible therapeutic intervention.

In silico targeting of colony-stimulating factor-1 receptor: delineating immunotherapy in cancer

Aim

Delineate structure-based inhibition of colony-stimulating factor-1 receptor (CSF1R) by small molecule CSF1R inhibitors in clinical development for target identification and potential lead optimization in cancer therapeutics since CSF1R is a novel predictive biomarker for immunotherapy in cancer.

Methods

Compounds were in silico modelled by induced fit docking protocol in a molecular operating environment (MOE, MOE.v.2015). The 3-dimensional (3D) X-ray crystallized structure of CSF1R kinase (Protein Databank, ID 4R7H) was obtained from Research Collaboratory for Structural Bioinformatics (RSCB) Protein Databank. The 3D conformers of edicotinib, DCC-3014, ARRY-382, BLZ-945, chiauranib, dovitinib, and sorafenib were obtained from PubChem Database. These structures were modelled in Amber10:EHT molecular force field, and quick prep application was used to correct and optimize the structures for missing residues, H-counts, termini capping, and alternates. The binding site was defined within the vicinity of the co-crystallized ligand of CSF1R kinase. The compounds were docked by the triangular matcher placement method and ranked by the London dG scoring function. The docked poses were further refined by the induced fit method. The pose with the lowest binding score (ΔG) was used to model the ligand interaction profile in Discovery Studio Visualizer v17.2. The co-crystallized ligand was docked in its apo conformation, and root-mean-square deviation was computed to validate the docking protocol.

Results

All 7 CSF1R inhibitors interact with residue Met637 exhibiting selectivity except for edicotinib. The inhibitors maintain CSF1R in an auto-inhibitory conformation by interacting with Asp797 of the Asp-Phe-Gly (DFG) motif and/or hindering the conserved salt bridge formed between Glu633 and Lys616 thus stabilizing the activation loop, or interacting with tryptophan residue (Trp550) in the juxtamembrane domain. DCC-3014, ARRY-382, BLZ-945, and sorafenib bind with the lowest binding energy with CSF1R kinase.

Conclusions

Pyrimidines are potent inhibitors that interact with CSF1R residues. DCC-3014 and ARRY-382 exhibit exceptional pharmaceutical potential exhibiting great structural stability and affinity.

SOHO State of the Art Updates and Next Questions | New Pathways and New Targets in PTCL: Staying on Target

While the peripheral T-cell lymphomas (PTCL) remain a therapeutic challenge, and increasingly account for a disproportionate number of lymphoma-related deaths, improved understanding of disease pathogenesis and classification, and the development of novel therapeutic agents over the past decade, all provide reasons for a more optimistic outlook in the next. Despite their genetic and molecular heterogeneity, many PTCL are dependent upon signaling input provided by antigen, costimulatory, and cytokine receptors. While gain-of-function alterations effecting these pathways are recurrently observed in many PTCL, more often than not, signaling remains ligand-and tumor microenvironment (TME)-dependent. Consequently, the TME and its constituents are increasingly recognized as "on target". Utilizing a "3 signal" model, we will review new-and old-therapeutic targets that are relevant for the more common nodal PTCL subtypes.

Systematic Assessment of Protein C-Termini Mutated in Human Disorders

All proteins have a carboxyl terminus, and we previously summarized eight mutations in binding and trafficking sequence determinants in the C-terminus that, when disrupted, cause human diseases. These sequence elements for binding and trafficking sites, as well as post-translational modifications (PTMs), are called minimotifs or short linear motifs. We wanted to determine how frequently mutations in minimotifs in the C-terminus cause disease. We searched specifically for PTMs because mutation of a modified amino acid almost always changes the chemistry of the side chain and can be interpreted as loss-of-function. We analyzed data from ClinVar for disease variants, Minimotif Miner and the C-terminome for PTMs, and RefSeq for protein sequences, yielding 20 such potential disease-causing variants. After additional screening, they include six with a previously reported PTM disruption mechanism and nine with new hypotheses for mutated minimotifs in C-termini that may cause disease. These mutations were generally for different genes, with four different PTM types and several different diseases. Our study helps to identify new molecular mechanisms for nine separate variants that cause disease, and this type of analysis could be extended as databases grow and to binding and trafficking motifs. We conclude that mutated motifs in C-termini are an infrequent cause of disease.

PTCL, NOS: An update on classification, risk-stratification, and treatment

The peripheral T-cell lymphomas (PTCL) are relatively rare, heterogeneous, and therapeutically challenging. While significant therapeutic gains and improved understanding of disease pathogenesis have been realized for selected PTCL subtypes, the most common PTCL in North America remains "not otherwise specified (NOS)" and is an unmet need. However, improved understanding of the genetic landscape and ontogeny for the PTCL subtypes currently classified as PTCL, NOS have been realized, and have significant therapeutic implications, which will be reviewed here.

Antitumor activity of a pexidartinib bioisostere inhibiting CSF1 production and CSF1R kinase activity in human hepatocellular carcinoma

Macrophage colony-stimulating factor (M-CSF, also known as CSF1) in tumor tissues stimulates tumor growth and tumor-induced angiogenesis through an autocrine and paracrine action on CSF1 receptor (CSF1R). In the present study, novel bioisosteres of pexidartinib (1) were synthesized and evaluated their inhibitory activities against CSF1R kinase and tumor growth. Among newly synthesized bioisosteres, compound 3 showed the highest inhibition (95.1%) against CSF1R tyrosine kinase at a fixed concentration (1 μM). The half maximal inhibitory concentration (IC₅₀) of pexidartinib (1) and compound 3 was 2.7 and 57.8 nM, respectively. Unlike pexidartinib (1), which cross-reacts to three targets with structural homology, such as CSF1R, c-KIT, and FLT3, compound 3 inhibited CSF1R, c-KIT, but not FLT3, indicating compound 3 may be a more selective CSF1R inhibitor than pexidartinib (1). The inhibitory effect of compound 3 on the proliferation of various cancer cell lines was the strongest in U937 cells followed by THP-1 cells. In the case of cancer cell lines derived from solid tumors, the anti-proliferative activity of compound 3 was weaker than pexidartinib (1), except for Hep3B. However, compound 3 was safer than pexidartinib (1) in terminally differentiated normal cells such as macrophages. Pexidartinib (1) and compound 3 suppressed the production of CSF1 in Hep3B liver cancer cells as well as in the co-culture of Hep3B cells and macrophages. Also, pexidartinib (1) and compound 3 decreased the population ratio of the M2/M1 phenotype and inhibited their migration. Importantly, compound 3 preferentially inhibited M2 phenotype over M1, and the effect was about 4 times greater than that of pexidartinib (1). In addition, compound 3 inhibited maintenance of cancer stem cell population. In a chick chorioallantoic membrane (CAM) tumor model implanted with Hep3B cells, tumor growth and tumor-induced angiogenesis were significantly blocked by compound 3 to a similar extent as pexidartinib (1). Overall, compound 3, a bioisostere of pexidartinib, is an effective dual inhibitor to block CSF1R kinase and CSF1 production, resulting in significant inhibition of tumor growth.

Silence of a dependence receptor CSF1R in colorectal cancer cells activates tumor-associated macrophages

BACKGROUND

Colony-stimulating factor 1 receptor (CSF1R), a classic tyrosine kinase receptor, has been identified as a proto-oncogene in multiple cancers. The CSF1/CSF1R axis is essential for the survival and differentiation of M2-phenotype tumor-associated macrophages (M2 TAMs). However, we found here that the CSF1R expression was abnormally down-regulated in colorectal cancer (CRC), and its biological functions and underlying mechanisms have become elusive in CRC progression.

METHODS

The expression of class III receptor tyrosine kinases in CRC and normal intestinal mucosa was accessed using The Cancer Genome Atlas and Gene Expression Omnibus datasets and was further validated by our tested cohort. CSF1R was reconstructed in CRC cells to identify its biological functions in vitro and in vivo. We compared CSF1R expression and methylation differences between CRC cells and macrophages. Furthermore, a co-culture system was used to mimic a competitive mechanism between CSF1R-overexpressed CRC cells and M2-like macrophages. We utilized a CSF1R inhibitor PLX3397 to ablate M2 TAMs and evaluated its efficacy on CRC treatment in animal models.

RESULTS

We found here that the CSF1R is silenced in CRC, and the reintroduced expression of the receptor in CRC cells can be cleaved by caspases and constrain tumor growth in vitro and in vivo, functioning as a tumor suppressor gene. We further identified CSF1R as a novel dependence receptor, which has the potential to act as either a tumor suppressor gene or an oncogene, depending on its activated state. In CRC tumors, CSF1R expression is enriched in TAMs, and its expression is associated with poor prognosis in patients ith CRC. In a co-culture system, CRC cells expressing CSF1R compete with M2-like macrophages for CSF1R ligands, resulting in a decrease in CSF1R activation and cell proliferation in macrophages. Blocking CSF1R by PLX3397 could deplete M2 TAMs and augments CD8⁺ T cell infiltration, effectively inhibiting tumor growth and metastasis and improving responses to chemotherapy and immunotherapy.

CONCLUSION

Our findings revealed that CSF1R is a novel identified dependence receptor silenced in CRC. The silence abalienates its ligands to stimulate CSF1R expressed on M2 TAMs, which is an appealing therapeutic target for M2 TAM depletion and CRC treatment.

Targeting Lymphoma-associated Macrophage Expansion via CSF1R/JAK Inhibition is a Therapeutic Vulnerability in Peripheral T-cell Lymphomas

The reciprocal relationship between malignant T cells and lymphoma-associated macrophages (LAM) within the tumor microenvironment (TME) is unique, as LAMs are well poised to provide ligands for antigen, costimulatory, and cytokine receptors that promote T-cell lymphoma growth. Conversely, malignant T cells promote the functional polarization and homeostatic survival of LAM. Therefore, we sought to determine the extent to which LAMs are a therapeutic vulnerability in these lymphomas, and to identify effective therapeutic strategies for their depletion. We utilized complementary genetically engineered mouse models and primary peripheral T-cell lymphoma (PTCL) specimens to quantify LAM expansion and proliferation. A high-throughput screen was performed to identify targeted agents that effectively deplete LAM within the context of PTCL. We observed that LAMs are dominant constituents of the TME in PTCL. Furthermore, their dominance was explained, at least in part, by their proliferation and expansion in response to PTCL-derived cytokines. Importantly, LAMs are a true dependency in these lymphomas, as their depletion significantly impaired PTCL progression. These findings were extrapolated to a large cohort of human PTCL specimens where LAM proliferation was observed. A high-throughput screen demonstrated that PTCL-derived cytokines led to relative resistance to CSF1R selective inhibitors, and culminated in the identification of dual CSF1R/JAK inhibition as a novel therapeutic strategy to deplete LAM in these aggressive lymphomas. Malignant T cells promote the expansion and proliferation of LAM, which are a bone fide dependency in these lymphomas, and are effectively depleted with a dual CSF1R/JAK inhibitor.

Significance

LAMs are a therapeutic vulnerability, as their depletion impairs T-cell lymphoma disease progression. Pacritinib, a dual CSF1R/JAK inhibitor, effectively impaired LAM viability and expansion, prolonged survival in preclinical T-cell lymphoma models, and is currently being investigated as a novel therapeutic approach in these lymphomas.

Discovery of vimseltinib (DCC-3014), a highly selective CSF1R switch-control kinase inhibitor, in clinical development for the treatment of Tenosynovial Giant Cell Tumor (TGCT)

Based on knowledge of kinase switch-control inhibition and using a combination of structure-based drug design and standard medicinal chemistry principles, we identified a novel series of dihydropyrimidone-based CSF1R kinase inhibitors displaying exquisite selectivity for CSF1R versus a large panel of kinases and non-kinase protein targets. Starting with lead compound 3, an SAR optimization campaign led to the discovery of vimseltinib (DCC-3014; compound 20) currently undergoing clinical evaluation for the treatment of Tenosynovial Giant Cell Tumor (TGCT), a locally aggressive benign tumor associated with substantial morbidity. 2021 Elsevier ltd. All rights reserved.

Discovery of acyl ureas as highly selective small molecule CSF1R kinase inhibitors

Based on the structure of an early lead identified in Deciphera's proprietary compound collection of switch control kinase inhibitors and using a combination of medicinal chemistry guided structure activity relationships and structure-based drug design, a novel series of potent acyl urea-based CSF1R inhibitors was identified displaying high selectivity for CSF1R versus the other members of the Type III receptor tyrosine kinase (RTK) family members (KIT, PDGFR-α, PDGFR-β, and FLT3), VEGFR2 and MET. Based on in vitro biology, in vitro ADME and in vivo PK/PD studies, compound 10 was selected as an advanced lead for Deciphera's CSF1R research program.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Combined High-Throughput Approaches Reveal the Signals Driven by Skin and Blood Environments and Define the Tumor Heterogeneity in Sézary Syndrome

Simple Summary

Sézary syndrome (SS) is a leukemic and incurable variant of cutaneous T-cell lymphoma characterized by the accumulation of neoplastic CD4+ lymphocytes in the blood, lymph nodes, and skin. With the exception of allogenic transplantation, no curative chance is available to treat SS, and it is a priority to find new therapies that target SS cells within all disease compartments. This review aims to summarize the more recent analyses conducted on skin- and blood-derived SS cells concurrently obtained from the same SS patients. The results highlighted that skin-SS cells were more active/proliferating with respect to matched blood SS cells that instead appeared quiescent. These data shed the light on the possibility to treat blood and skin SS cells with different compounds, respectively. Moreover, this review recaps the more recent findings on the heterogeneity of circulating SS cells that presented a series of novel markers that could improve diagnosis, prognosis and therapy of this lymphoma.

Abstract

Sézary syndrome (SS) is an aggressive variant of cutaneous t-cell lymphoma characterized by the accumulation of neoplastic CD4+ lymphocytes—the SS cells—mainly in blood, lymph nodes, and skin. The tumor spread pattern of SS makes this lymphoma a unique model of disease that allows a concurrent blood and skin sampling for analysis. This review summarizes the recent studies highlighting the transcriptional programs triggered by the crosstalk between SS cells and blood–skin microenvironments. Emerging data proved that skin-derived SS cells show consistently higher activation/proliferation rates, mainly driven by T-cell receptor signaling with respect to matched blood SS cells that instead appear quiescent. Biochemical analyses also demonstrated an hyperactivation of PI3K/AKT/mTOR, a targetable pathway by multiple inhibitors currently in clinical trials, in skin SS cells compared with a paired blood counterpart. These results indicated that active and quiescent SS cells coexist in this lymphoma, and that they could be respectively treated with different therapeutics. Finally, this review underlines the more recent discoveries into the heterogeneity of circulating SS cells, highlighting a series of novel markers that could improve the diagnosis and that represent novel therapeutic targets (GPR15, PTPN13, KLRB1, and ITGB1) as well as new genetic markers (PD-1 and CD39) able to stratify SS patients for disease aggressiveness.

CSF-1R inhibitor, pexidartinib, sensitizes esophageal adenocarcinoma to PD-1 immune checkpoint blockade in a rat model

Esophageal adenocarcinoma (EAC) is a leading cause of cancer deaths. Pexidartinib, a multi-gene tyrosine kinase inhibitor, through targeting CSF-1R, down modulates macrophage mediated pro-survival tumor signaling. Previously, CSF-1R inhibitors have successfully shown to enhance antitumor activity of PD-1/PD-L1 inhibitors by suppressing tumor immune evasion, in solid tumors. In this study, we investigated the antitumor activity of pexidartinib alone or in combination with blockade of PD-1 in a de novo EAC rat model. Here, we showed limited toxicity with significant tumor shrinkage in pexidartinib treated animals compared to controls, single agent and in combination with a PD-1 inhibitor, AUNP-12. Suppression of CSF-1/CSF-1R axis resulted in enhanced infiltration of CD3+CD8+ T cells with reduced M2 macrophage polarization, in the tumor microenvironment (TME). Endpoint tissue gene expression in pexidartinib treated animals demonstrated upregulation of BAX, Cas3, TNFα, IFNγ and IL6 and downregulation of Ki67, IL13, IL10, TGFβ and Arg1 (p<0.05). Additionally, among the pexidartinib treated animals responders compared to non-responders demonstrated a significant upregulation of pre-treatment CSF-1 gene, confirming that tumor associated macrophage suppression directly translates to clinical benefit. Moreover, a post-treatment serum cytokine assay exhibited similar systemic trends as the gene expression in the TME, depicting increases in pro-inflammatory cytokines and decreases in anti-inflammatory cytokines. In conclusion, our study established a promising combinatorial strategy using a CSF-1R inhibitor to overcome resistance to PD-1/PD-L1 axis blockade in an EAC model, providing the rationale for future clinical strategies.

Screening and Analysis of Biomarkers in the miRNA-mRNA Regulatory Network of Osteosarcoma

Osteosarcoma is a malignant disease, and few effective strategies can completely overcome the prognosis of these patients. This study attempted to reveal the key factors and related molecular mechanisms of osteosarcoma via excavating public microarray datasets. The data were obtained from the Gene Expression Omnibus (GEO) database; the differentially expressed miRNAs and differentially expressed genes were obtained in GSE69470 and GSE12685l, respectively; the target of miRNAs were predicted with the miRDIP database; the functions of the factors were analyzed and visualized by the David database and R language, respectively. Moreover, the protein-protein interaction network and miRNA-mRNA network were performed with the STRING database and Cytoscape software to identify the hub nodes in GSE69470 and GSE12685. The results showed that 834 DEGs were found in GSE12685 and 37 miRNAs were found in GSE69470. Moreover, the target of 37 miRNAs were enriched in PI3K/AKT, P53, Wnt/β-catenin, and TGF-β pathways and related with skeletal system development and cell growth. Besides, the miRNAs including miR-22-3p, miR-154-5p, miR-34a-5p, miR-485-3p, miR-93-5p, and miR-9-5p and the genes including LEF1, RUNX2, CSF1R, CDKN1A, and FBN1 were identified as the hub nodes via network analysis. In conclusion, this study suggested that the miRNAs including miR-22-3p, miR-154-5p, miR-34a-5p, miR-485-3p, miR-93-5p, and miR-9-5p and the genes including LEF1, RUNX2, CSF1R, CDKN1A, and FBN1 act as key factors in the progression of osteosarcoma.

High Expression of CSF-1R Predicts Poor Prognosis and CSF-1Rhigh Tumor-Associated Macrophages Inhibit Anti-Tumor Immunity in Colon Adenocarcinoma

Background

Colony stimulating factor 1 receptor (CSF-1R) is a single channel III transmembrane receptor tyrosine kinase (RTK) and plays an important role in immune regulation and the development of various cancer types. The expression of CSF-1R in colon adenocarcinoma (COAD) and its prognostic value remain incompletely understood. Therefore, we aim to explore the prognostic value of CSF-1R in COAD and its relationship with tumor immunity.

Methods

CSF-1R expression in a COAD cohort containing 103 patients was examined using immunohistochemistry (IHC). The relationship between CSF-1R expression and clinicopathological parameters and prognosis was evaluated. Dual immunofluorescence staining was conducted to determine the localization of CSF-1R in COAD tissues. Univariate and multivariate Cox regression analysis were performed to evaluate independent prognostic factors. Transcriptomic profiles of CSF-1R^high and CSF-1R^low tumor-associated macrophages (TAMs) were investigated. Gene enrichment analysis was used to explore the signal pathways related to CSF-1R. In addition, the relationship between CSF-1R in tumor microenvironment (TME) and tumor immunity was also studied.

Results

IHC analysis showed that CSF-1R was overexpressed in COAD, and higher expression was associated with shorter overall survival (OS). Immunofluorescence staining showed that CSF-1R was co-localized with macrophage marker CD68. Univariate and multivariate Cox regression analysis showed that CSF-1R was an independent prognostic factor for COAD. The results of gene enrichment analysis showed that CSF-1R was involved in tumor immune response and regulation of TME. In addition, CSF-1R was significantly correlated with TME, immune cell infiltration, TMB, MSI, Neoantigen, and immune checkpoint molecules.

Conclusion

CSF-1R can serve as an independent prognostic factor of COAD and promising immunotherapeutic target of COAD.

Inhibition of colony stimulating factor-1 receptor (CSF-1R) as a potential therapeutic strategy for neurodegenerative diseases: opportunities and challenges

Microglia are specialized dynamic immune cells in the central nervous system (CNS) that plays a crucial role in brain homeostasis and in disease states. Persistent neuroinflammation is considered a hallmark of many neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson's disease (PD), Huntington’s disease (HD), amyotrophic lateral sclerosis (ALS) and primary progressive multiple sclerosis (MS). Colony stimulating factor 1-receptor (CSF-1R) is predominantly expressed on microglia and its expression is significantly increased in neurodegenerative diseases. Cumulative findings have indicated that CSF-1R inhibitors can have beneficial effects in preclinical neurodegenerative disease models. Research using CSF-1R inhibitors has now been extended into non-human primates and humans. This review article summarizes the most recent advances using CSF-1R inhibitors in different neurodegenerative conditions including AD, PD, HD, ALS and MS. Potential challenges for translating these findings into clinical practice are presented.

Vav1 Promotes B-Cell Lymphoma Development

Vav1 is normally and exclusively expressed in the hematopoietic system where it functions as a specific GDP/GTP nucleotide exchange factor (GEF), firmly regulated by tyrosine phosphorylation. Mutations and overexpression of Vav1 in hematopoietic malignancies, and in human cancers of various histologic origins, are well documented. To reveal whether overexpression of Vav1 in different tissues suffices for promoting the development of malignant lesions, we expressed Vav1 in transgenic mice by using the ubiquitous ROSA26 promoter (Rosa Vav1). We detected Vav1 expression in epithelial tissues of various organs including pancreas, liver, and lung. While carcinomas did not develop in these organs, surprisingly, we noticed the development of B-cell lymphomas. Rac1-GTP levels did not change in tissues from Rosa Vav1 mice expressing the transgenic Vav1, while ERK phosphorylation increased in the lymphomas, suggesting that signaling pathways are evoked. One of the growth factors analyzed by us as a suspect candidate to mediate paracrine stimulation in the lymphocytes was CSF-1, which was highly expressed in the epithelial compartment of Rosa Vav1 mice. The expression of its specific receptor, CSF-1R, was found to be highly expressed in the B-cell lymphomas. Taken together, our results suggest a potential cross-talk between epithelial cells expressing Vav1, that secrete CSF-1, and the lymphocytes that express CSF-1R, thus leading to the generation of B-cell lymphomas. Our findings provide a novel mechanism by which Vav1 contributes to tumor propagation.

Sustained, complete response to pexidartinib in a patient with CSF1R-mutated Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a histiocytic neoplasm that predominantly harbors mitogen-activated protein kinase (MAPK) pathway variants. MAPK inhibitors typically are effective treatments, but mutations outside the MAPK pathway, such as CSF1R variants, may cause refractory ECD. We describe a patient with a novel somatic mutation in CSF1R (CSF1R^{R549_E554delinsQ} ) that resulted in refractory ECD affecting the central nervous system. Cell model studies, RNA sequencing analysis, and in silico protein modeling suggested that she had a gain-of-function mutation occurring in a region critical for autoinhibition. The patient was treated with pexidartinib, a CSF1R inhibitor, and has had a complete clinical and metabolic response lasting more than 1.5 years to date. To our knowledge, this is the first report to describe successful treatment of a patient with ECD by using an agent that specifically targets CSF1R. This case also highlights the critical role of individualized molecular profiling to identify novel therapeutic targets in ECD.

Interfering with alternatively activated macrophages by CSF-1R inhibition exerts therapeutic capacity on allergic airway inflammation

PURPOSE

Allergic asthma is a chronic inflammatory disorder with airway hyperresponsiveness and tissue remodeling as the main pathological characteristics. The etiology of asthma is relatively complicated, involving genetic susceptibility, epigenetic regulation, environmental factors, and immune imbalance. Colony stimulating factor 1 receptor (CSF-1R), highly expressed in myeloid monocytes, plays an important role in regulating inflammation. However, the pathological role of CSF-1R and the therapeutic effects of CSF-1R inhibitor in allergic airway inflammation remain indistinct.

METHODS

The house dust mite (HDM)-triggered allergic airway inflammation model was conducted to fully uncover the efficacies of CSF-1R inhibition, as illustrated by histopathological examinations, biochemical analysis, ELISA, RT-PCR, Western blotting assay, immunofluorescence, and flow cytometry. Furthermore, bone marrow-derived macrophages (BMDMs) were differentiated and polarized upon IL-4/IL-13 induction to clarify the underlying mechanisms of CSF-1R inhibition.

RESULTS

Herein, we presented that the expression of CSF-1R was increased in HDM-induced experimental asthma and inhibition of CSF-1R displayed dramatic effects on the disease severity of asthma, referring to suppressing the secretion of allergic mediators, dysfunction of airway epithelium, and infiltration of inflammatory cells. Furthermore, CSF-1R inhibitor could markedly restrain the polarization and expression of transcriptional factors of alternatively activated macrophages (AAMs) in the presence of IL-4/IL-13 and reduce the recruitment of CSF-1R-dominant macrophages, both in acute and chronic allergic airway inflammation model.

CONCLUSION

Collectively, our findings demonstrated the molecular pathological mechanism of CSF-1R in allergic airway diseases and suggested that targeting CSF-1R might be an alternative intervention strategy on the homeostasis of airway immune microenvironment in asthma.

Bioinformatics study on different gene expression profiles of fibroblasts and vascular endothelial cells in keloids

Keloid is a benign fibroproliferative skin tumor. The respective functions of fibroblasts and vascular endothelial cells in keloid have not been fully studied. The purpose of this study is to identify the respective roles and key genes of fibroblasts and vascular endothelial cells in keloids, which can be used as new targets for diagnosis or treatment.The microarray datasets of keloid fibroblasts and vascular endothelial cells were obtained from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened out. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used for functional enrichment analysis. The search tool for retrieval of interacting genes and Cytoscape were used to construct protein-protein interaction (PPI) networks and analyze gene modules. The hub genes were screened out, and the relevant interaction networks and biological process analysis were carried out.In fibroblasts, the DEGs were significantly enriched in collagen fibril organization, extracellular matrix organization and ECM-receptor interaction. The PPI network was constructed, and the most significant module was selected, which is mainly enriched in ECM-receptor interaction. In vascular endothelial cells, the DEGs were significantly enriched in cytokine activity, growth factor activity and transforming growth factor-β (TGF-β) signaling pathway. Module analysis was mainly enriched in TGF-β signaling pathway. Hub genes were screened out separately.In summary, the DEGs and hub genes discovered in this study may help us understand the molecular mechanisms of keloid, and provide potential targets for diagnosis and treatment.

Microglia Reduce Herpes Simplex Virus 1 Lethality of Mice with Decreased T Cell and Interferon Responses in Brains

Herpes simplex virus 1 (HSV-1) infects the majority of the human population and can induce encephalitis, which is the most common cause of sporadic, fatal encephalitis. An increase of microglia is detected in the brains of encephalitis patients. The issues regarding whether and how microglia protect the host and neurons from HSV-1 infection remain elusive. Using a murine infection model, we showed that HSV-1 infection on corneas increased the number of microglia to outnumber those of infiltrating leukocytes (macrophages, neutrophils, and T cells) and enhanced microglia activation in brains. HSV-1 antigens were detected in brain neurons, which were surrounded by microglia. Microglia depletion increased HSV-1 lethality of mice with elevated brain levels of viral loads, infected neurons, neuron loss, CD4 T cells, CD8 T cells, neutrophils, interferon (IFN)-β, and IFN-γ. In vitro studies demonstrated that microglia from infected mice reduced virus infectivity. Moreover, microglia induced IFN-β and the signaling pathway of signal transducer and activator of transcription (STAT) 1 to inhibit viral replication and damage of neurons. Our study reveals how microglia protect the host and neurons from HSV-1 infection.

Colony Stimulating Factor-1 and its Receptor in Gastrointestinal Malignant Tumors

Gastrointestinal malignant tumor is the fourth most common cancer in the world and the second cause of cancer death. Due to the susceptibility to lymphatic metastasis and liver metastasis, the prognosis of advanced tumor patients is still poor till now. With the development of tumor molecular biology, the tumor microenvironment and the cytokines, which are closely related to the proliferation, infiltration and metastasis, have become a research hotspot in life sciences. Colony stimulating factor-1 (CSF-1), a polypeptide chain cytokine, and its receptor CSF-1R are reported to play important roles in regulating tumor-associated macrophages in tumor microenvironment and participating in the occurrence and development in diversities of cancers. Targeted inhibition of the CSF-1/CSF-1R signal axis has broad application prospects in cancer immunotherapy. Here, we reviewed the biological characters of CSF-1/CSF-1R and their relationship with gastrointestinal malignancies.

Small-Molecule Anti-Cancer Drugs From 2016 to 2020: Synthesis and Clinical Application

Malignant tumors have become a significant public health problem that severely threatens human health. Drug-targeting therapy is essential for tumor therapy, along with surgery and radiotherapy. Of the 378 novel drugs approved over the past five years, those for oncological therapy remains at the top (25%). These drugs are used to treat patients with various cancers by acting on corresponding targets, such as EGFR, JAK, BTK, IDH, and FLT3. This review examines anti-tumor agents approved between 2016 and 2020, classifying them according to indication (such as lung cancer, leukemia, breast cancer, and myeloma). These drugs are reviewed according to their route of administration, first-in-class designation, approval dates, and expedited review categories. Furthermore, this paper summarizes the targets and modes of action of the approved anti-tumor drugs while systematically discussing their synthetic routes for medicinal chemistry or industrial use, which will benefit next-generation drug discovery.

A Pan-cancer Analysis Reveals the Abnormal Expression and Drug Sensitivity of CSF1

BACKGROUND

Colony-stimulating factor-1 (CSF1) is a cytokine that is closely related to normal organ growth and development as well as tumor progression.

OBJECTIVE

We aimed to summarize and clarify the reasons for the abnormal expression of CSF1 in tumors and explore the role of CSF1 in tumor progression. Furthermore, drug response analysis may provide a reference for clinical medication.

METHODS

The expression of CSF1 was analyzed by TCGA and CCLE. Besides, cBioPortal and MethSurv databases were used to conduct mutation and DNA methylation analyses. Further, correlations between CSF1 expression and tumor stage, survival, immune infiltration, drug sensitivity and enrichment analyses were validated via UALCAN, Kaplan-Meier plotter, TIMER, CTRP and Coexperia databases.

RESULTS

CSF1 is expressed in a variety of tissues, meaningfully, it can be detected in blood. Compared with normal tissues, CSF1 expression was significantly decreased in most tumors. The missense mutation and DNA methylation of CSF1 may cause the downregulated expression. Moreover, decreased CSF1 expression was related with higher tumor stage and worse survival. Further, the promoter DNA methylation level of CSF1 was prognostically significant in most tumors. Besides, CSF1 was closely related to immune infiltration, especially macrophages. Importantly, CSF1 expression was associated with a good response to VEGFRs inhibitors, which may be due to the possible involvement of CSF1 in tumor angiogenesis and metastasis processes.

CONCLUSION

The abnormal expression of CSF1 could serve as a promising biomarker of tumor progression and prognosis in pan-cancer. Significantly, angiogenesis and metastasis inhibitors may show a good response to CSF1-related tumors.

Current Methods of Post-Translational Modification Analysis and Their Applications in Blood Cancers

Post-translational modifications (PTMs) add a layer of complexity to the proteome through the addition of biochemical moieties to specific residues of proteins, altering their structure, function and/or localization. Mass spectrometry (MS)-based techniques are at the forefront of PTM analysis due to their ability to detect large numbers of modified proteins with a high level of sensitivity and specificity. The low stoichiometry of modified peptides means fractionation and enrichment techniques are often performed prior to MS to improve detection yields. Immuno-based techniques remain popular, with improvements in the quality of commercially available modification-specific antibodies facilitating the detection of modified proteins with high affinity. PTM-focused studies on blood cancers have provided information on altered cellular processes, including cell signaling, apoptosis and transcriptional regulation, that contribute to the malignant phenotype. Furthermore, the mechanism of action of many blood cancer therapies, such as kinase inhibitors, involves inhibiting or modulating protein modifications. Continued optimization of protocols and techniques for PTM analysis in blood cancer will undoubtedly lead to novel insights into mechanisms of malignant transformation, proliferation, and survival, in addition to the identification of novel biomarkers and therapeutic targets. This review discusses techniques used for PTM analysis and their applications in blood cancer research.

Integrative Statistics, Machine Learning and Artificial Intelligence Neural Network Analysis Correlated CSF1R with the Prognosis of Diffuse Large B-Cell Lymphoma

Tumor-associated macrophages (TAMs) of the immune microenvironment play an important role in the Diffuse Large B-cell Lymphoma (DLBCL) pathogenesis. This research aimed to characterize the expression of macrophage colony-stimulating factor 1 receptor (CSF1R) at the gene and protein level in correlation with survival. First, the immunohistochemical expression of CSF1R was analyzed in a series of 198 cases from Tokai University Hospital and two patterns of histological expression were found, a TAMs, and a diffuse B-lymphocytes pattern. The clinicopathological correlations showed that the CSF1R + TAMs pattern associated with a poor progression-free survival of the patients, disease progression, higher MYC proto-oncogene expression, lower MDM2 expression, BCL2 translocation, and a MYD88 L265P mutation. Conversely, a diffuse CSF1R + B-cells pattern was associated with a favorable progression-free survival. Second, the histological expression of CSF1R was also correlated with 10 CSF1R-related markers including CSF1, STAT3, NFKB1, Ki67, MYC, PD-L1, TNFAIP8, IKAROS, CD163, and CD68. CSF1R moderately correlated with STAT3, TNFAIP8, CD68, and CD163 in the cases with the CSF1R + TAMs pattern. In addition, machine learning modeling predicted the CSF1R immunohistochemical expression with high accuracy using regression, generalized linear, an artificial intelligence neural network (multilayer perceptron), and support vector machine (SVM) analyses. Finally, a multilayer perceptron analysis predicted the genes associated with the CSF1R gene expression using the GEO GSE10846 DLBCL series of the Lymphoma/Leukemia Molecular Profiling Project (LLMPP), with correlation to the whole set of 20,683 genes as well as with an immuno-oncology cancer panel of 1790 genes. In addition, CSF1R positively correlated with SIRPA and inversely with CD47. In conclusion, the CSF1R histological pattern correlated with the progression-free survival of the patients of the Tokai series, and predictive analytics is a feasible strategy in DLBCL.

Identification of an individualized RNA binding protein-based prognostic signature for diffuse large B-cell lymphoma

RNA binding proteins (RBPs) are increasingly appreciated as being essential for normal hematopoiesis and have a critical role in the progression of hematological malignancies. However, their functional consequences and clinical significance in diffuse large B‐cell lymphoma (DLBCL) remain unknown. Here, we conducted a systematic analysis to identify RBP‐related genes affecting DLBCL prognosis based on the Gene Expression Omnibus database. By univariate and multivariate Cox proportional hazards regression (CPHR) methods, six RBPs‐related genes (CMSS1, MAEL, THOC5, PSIP1, SNIP1, and ZCCHC7) were identified closely related to the overall survival (OS) of DLBCL patients. The RBPs signature could efficiently distinguished low‐risk from high‐risk patients and could serve as an independent and reliable factor for predicting OS. Moreover, Gene Set Enrichment Analysis revealed 17 significantly enriched pathways between high‐ versus low‐risk group, including the regulation of autophagy, chronic myeloid leukemia, NOTCH signaling pathway, and B cell receptor signaling pathway. Then we developed an RBP‐based nomogram combining other clinical risk factors. The receiver operating characteristic curve analysis demonstrated high prognostic predictive efficiency of this model with the area under the curve values were 0.820 and 0.780, respectively, in the primary set and entire set. In summary, our RBP‐based model could be a novel prognostic predictor and had the potential for developing treatment targets for DLBCL.

Patient-Derived Tumor Xenografts Plus Ex Vivo Models Enable Drug Validation for Tenosynovial Giant Cell Tumors

INTRODUCTION

Tenosynovial giant cell tumor (TGCT) is a locally aggressive tumor with colony-stimulating factor 1 receptor (CSF1R) signal expression. However, there is a lack of better in vivo and ex vivo models for TGCT. This study aims to establish a favorable preclinical translational platform, which would enable the validation of efficient and personalized therapeutic candidates for TGCT.

PATIENTS AND METHODS

Histological analyses were performed for the included patients. Fresh TGCT tumors were collected and sliced into 1.0-3.0 mm³ sections using a sterilized razor blade. The tumor grafts were surgically implanted into subrenal capsules of athymic mice to establish patient-derived tumor xenograft (PDTX) mouse models. Histological and response patterns to CSF1R inhibitors evaluations were analyzed. In addition, ex vivo cultures of patient-derived explants (PDEs) with endpoint analysis were used to validate TGCT graft response patterns to CSF1R inhibitors.

RESULTS

The TGCT tumor grafts that were implanted into athymic mice subrenal capsules maintained their original morphological and histological features. The "take" rate of this model was 95% (19/20). Administration of CSF1R inhibitors (PLX3397, and a novel candidate, WXFL11420306) to TGCT-PDTX mice was shown to reduce tumor size while inducing intratumoral apoptosis. In addition, the CSF1R inhibitors suppressed circulating nonspecific monocyte levels and CD163-positive cells within tumors. These response patterns of engrafts to PDTX were validated by ex vivo PDE cultures.

CONCLUSIONS

Subrenal capsule supports the growth of TGCT tumor grafts, maintaining their original morphology and histology. This TGCT-PDTX model plus ex vivo explant cultures is a potential preclinical translational platform for locally aggressive tumors, such as TGCT.

CSF1/CSF1R-mediated Crosstalk Between Choroidal Vascular Endothelial Cells and Macrophages Promotes Choroidal Neovascularization

Purpose

This study examined the role of the CSF1/CSF1Raxis in the crosstalk between choroidal vascular endothelial cells (CVECs) and macrophages during the formation of choroidal neovascularization (CNV).

Methods

Quantitative reverse transcriptase (QRT)-PCR, Western blot and ELISA measured the production and release of CSF1 from human choroidal vascular endothelial cells (HCVECs) under hypoxic conditions. Western blot detected CSF1 released from HCVECs under hypoxic conditions that activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R. Transwell migration assay, qRT-PCR, and Western blot detected the effect of CSF1 released from HCVECs on macrophage migration and M2 polarization via the CSF1R/PI3K/AKT/FOXO1 pathway. Incorporation of 5-ethynyl-20-deoxyuridine, transwell migration, and tube formation assays detected the effects of CSF1/CSF1R on the behaviors of HCVECs. Fundus fluorescein angiography (FFA), indocyanine green angiography (ICGA), and immunofluorescence detected the effect of blockade of CSF1/CSF1R on mouse laser-induced CNV. Color fundus photograph, ICGA, and FFA detected CNV lesions in neovascular AMD (nAMD) patients. ELISA detected CSF1 and CSF1R in the aqueous humor of age-related cataract and nAMD patients.

Results

CSF1 released from HCVECs under hypoxic conditions activated the PI3K/AKT/FOXO1 axis in human macrophages via binding to CSF1R, promoting macrophage migration and M2 polarization via up-regulation of the CSF1R/PI3K/AKT/FOXO1 pathway. Human macrophages promoted the proliferation, migration, and tube formation of HCVECs in a CSF1/CSFR1-dependent manner under hypoxic conditions. CSF1/CSF1R blockade ameliorated the formation of mouse laser-induced CNV. CSF1 and CSF1R were increased in the aqueous humor of nAMD patients.

Conclusions

Our results affirmed the crucial role of CSF1/CSF1R in boosting the formation of CNV and offered potential molecular targets for the treatment of nAMD.

CREBBP/EP300 mutations promoted tumor progression in diffuse large B-cell lymphoma through altering tumor-associated macrophage polarization via FBXW7-NOTCH-CCL2/CSF1 axis

Epigenetic alterations play an important role in tumor progression of diffuse large B-cell lymphoma (DLBCL). However, the biological relevance of epigenetic gene mutations on tumor microenvironment remains to be determined. The core set of genes relating to histone methylation (KMT2D, KMT2C, EZH2), histone acetylation (CREBBP, EP300), DNA methylation (TET2), and chromatin remodeling (ARID1A) were detected in the training cohort of 316 patients by whole-genome/exome sequencing (WGS/WES) and in the validation cohort of 303 patients with newly diagnosed DLBCL by targeted sequencing. Their correlation with peripheral blood immune cells and clinical outcomes were assessed. Underlying mechanisms on tumor microenvironment were investigated both in vitro and in vivo. Among all 619 DLBCL patients, somatic mutations in KMT2D (19.5%) were most frequently observed, followed by mutations in ARID1A (8.7%), CREBBP (8.4%), KMT2C (8.2%), TET2 (7.8%), EP300 (6.8%), and EZH2 (2.9%). Among them, CREBBP/EP300 mutations were significantly associated with decreased peripheral blood absolute lymphocyte-to-monocyte ratios, as well as inferior progression-free and overall survival. In B-lymphoma cells, the mutation or knockdown of CREBBP or EP300 inhibited H3K27 acetylation, downregulated FBXW7 expression, activated the NOTCH pathway, and downstream CCL2/CSF1 expression, resulting in tumor-associated macrophage polarization to M2 phenotype and tumor cell proliferation. In B-lymphoma murine models, xenografted tumors bearing CREBBP/EP300 mutation presented lower H3K27 acetylation, higher M2 macrophage recruitment, and more rapid tumor growth than those with CREBBP/EP300 wild-type control via FBXW7-NOTCH-CCL2/CSF1 axis. Our work thus contributed to the understanding of aberrant histone acetylation regulation on tumor microenvironment as an alternative mechanism of tumor progression in DLBCL.

PLX3397 treatment inhibits constitutive CSF1R-induced oncogenic ERK signaling, reduces tumor growth, and metastatic burden in osteosarcoma

Osteosarcoma (OSA) is a heterogeneous and aggressive solid tumor of the bone. We recently identified the colony stimulating factor 1 receptor (Csf1r) gene as a novel driver of osteosarcomagenesis in mice using the Sleeping Beauty (SB) transposon mutagenesis system. Here, we report that a CSF1R-CSF1 autocrine/paracrine signaling mechanism is constitutively activated in a subset of human OSA cases and is critical for promoting tumor growth and contributes to metastasis. We examined CSF1R and CSF1 expression in OSAs. We utilized gain-of-function and loss-of-function studies (GOF/LOF) to evaluate properties of cellular transformation, downstream signaling, and mechanisms of CSF1R-CSF1 action. Genetic perturbation of CSF1R in immortalized osteoblasts and human OSA cell lines significantly altered oncogenic properties, which were dependent on the CSF1R-CSF1 autocrine/paracrine signaling. These functional alterations were associated with changes in the known CSF1R downstream ERK effector pathway and mitotic cell cycle arrest. We evaluated the recently FDA-approved CSF1R inhibitor Pexidartinib (PLX3397) in OSA cell lines in vitro and in vivo in cell line and patient-derived xenografts. Pharmacological inhibition of CSF1R signaling recapitulated the in vitro genetic alterations. Moreover, in orthotopic OSA cell line and subcutaneous patient-derived xenograft (PDX)-injected mouse models, PLX3397 treatment significantly inhibited local OSA tumor growth and lessened metastatic burden. In summary, CSF1R is utilized by OSA cells to promote tumorigenesis and may represent a new molecular target for therapy.