Expression of CD74, the receptor for macrophage migration inhibitory factor, in non-small cell lung cancer

Single-cell RNA sequencing and spatial transcriptome reveal potential molecular mechanisms of lung cancer brain metastasis

BACKGROUND

Lung cancer is a highly aggressive and prevalent disease worldwide. By the time it is first diagnosed, distant metastases have usually already occurred. Among them, the prognosis of patients with brain metastasis from lung cancer is very poor. Therefore, it is particularly important to identify the evolutionary status of tumor cells during lung cancer brain metastases and discover the underlying mechanisms of lung cancer brain metastases.

METHODS

In this study, we analysed three types of data: single-cell RNA sequencing, bulk RNA sequencing, and spatial transcriptome. Firstly, we identified early metastatic epithelial cell clusters (EMEC) using CNV and trajectory analysis in scRNA-seq data. Secondly, we integrated scRNA-seq and spatial transcriptome data with the help of MIA (Multimodal intersection analysis) to explore the biological characteristics of EMEC. Finally, we used bulk RNA-seq data to validate the molecular characteristics of EMEC.

RESULT

A total of 55,763 single cells were obtained and divided into 9 cell types. In brain metastasis, we found a significantly higher proportion of epithelial cells. In addition, we identified a specific subpopulation of epithelial cells, which was named as "early metastatic epithelial cell clusters (EMEC)". It is enriched in oxidative phosphorylation, coagulation, complement. Moreover, we also found that EMEC underwent cellular communication with other immune cells through ligand-receptor pairs such as MIF-(CD74 + CXCR4) and MIF-(CD74 + CD44). Next, we validated that EMEC were associated with poor clinical prognosis using three independent external datasets. Finally, spatial transcriptome analysis revealed specificity in the spatial distribution of EMEC, which shifted from the peripheral regions to the central regions of the tumour as the depth of tumor invasion progressed.

CONCLUSION

This study reveals the potential molecular mechanisms of lung cancer brain metastasis from both single-cell and spatial transcriptomic perspectives, providing biological insights and clinical reference value for detecting patients suffering from lung cancer brain metastasis.

Host derived macrophage migration inhibitory factor expression attenuates anti-tumoral immune cell accumulation and promotes immunosuppression in the tumor microenvironment of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a significant public health concern worldwide. Immunomodulatory targets in the HNSCC tumor microenvironment are crucial to enhance the efficacy of HNSCC immunotherapy. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine that has been linked to poor prognosis in many cancers, but the mechanistic role of MIF in HNSCC remains unclear. Using a murine orthotopic oral cancer model in Mif+/+ or Mif-/- mice, we determined the function of host derived MIF in HNSCC tumor development, metastasis as well as localized and systemic tumor immune responses. We observed that Mif-/- mice have decreased tumor growth and tumor burden compared to their wild-type counterparts. Flow cytometric analysis of immune populations within the primary tumor site revealed increased Th1 and cytotoxic T cell recruitment to the HNSCC tumor microenvironment. Within the tumors of Mif-/- mice, MIF deletion also enhanced the effector function of anti-tumoral effector CD8+ T cells as well as Th1 cells and decreased the accumulation of granulocytic myeloid derived suppressor cells (g-MDSCs) in the tumor microenvironment. Furthermore, MDSCs isolated from tumor bearing mice chemotactically respond to MIF in a dose dependent manner. Taken together, our results demonstrate a chemotactic and immunomodulatory role for host derived MIF in promoting HNSCC and suggest that MIF targeted immunomodulation is a promising approach for HNSCC treatment.

Transcriptomic Analysis Reveals Early Alterations Associated with Intrinsic Resistance to Targeted Therapy in Lung Adenocarcinoma Cell Lines

Lung adenocarcinoma is the most prevalent form of lung cancer, and drug resistance poses a significant obstacle in its treatment. This study aimed to investigate the overexpression of long non-coding RNAs (lncRNAs) as a mechanism that promotes intrinsic resistance in tumor cells from the onset of treatment. Drug-tolerant persister (DTP) cells are a subset of cancer cells that survive and proliferate after exposure to therapeutic drugs, making them an essential object of study in cancer treatment. The molecular mechanisms underlying DTP cell survival are not fully understood; however, long non-coding RNAs (lncRNAs) have been proposed to play a crucial role. DTP cells from lung adenocarcinoma cell lines were obtained after single exposure to tyrosine kinase inhibitors (TKIs; erlotinib or osimertinib). After establishing DTP cells, RNA sequencing was performed to investigate the differential expression of the lncRNAs. Some lncRNAs and one mRNA were overexpressed in DTP cells. The clinical relevance of lncRNAs was evaluated in a cohort of patients with lung adenocarcinoma from The Cancer Genome Atlas (TCGA). RT-qPCR validated the overexpression of lncRNAs and mRNA in the residual DTP cells and LUAD biopsies. Knockdown of these lncRNAs increases the sensitivity of DTP cells to therapeutic drugs. This study provides an opportunity to investigate the involvement of lncRNAs in the genetic and epigenetic mechanisms that underlie intrinsic resistance. The identified lncRNAs and CD74 mRNA may serve as potential prognostic markers or therapeutic targets to improve the overall survival (OS) of patients with lung cancer.

Overexpression of ATP5F1A in Cardiomyocytes Promotes Cardiac Reverse Remodeling

BACKGROUND

The mechanism of cardiac reverse remodeling (CRR) mediated by the left ventricular assist device remains unclear. This study aims to identify the specific cell type responsible for CRR and develop the therapeutic target that promotes CRR.

METHODS

The nuclei were extracted from the left ventricular tissue of 4 normal controls, 4 CRR patients, and 4 no cardiac reverse remodeling patients and then subjected to single-nucleus RNA sequencing for identifying key cell types responsible for CRR. Gene overexpression in transverse aortic constriction and dilated cardiomyopathy heart failure mouse model (C57BL/6J background) and pathological staining were performed to validate the results of single-nucleus RNA sequencing.

RESULTS

Ten cell types were identified among 126 156 nuclei. Cardiomyocytes in CRR patients expressed higher levels of ATP5F1A than the other 2 groups. The macrophages in CRR patients expressed more anti-inflammatory genes and functioned in angiogenesis. Endothelial cells that elevated in no cardiac reverse remodeling patients were involved in the inflammatory response. Echocardiography showed that overexpressing ATP5F1A through cardiomyocyte-specific adeno-associated virus 9 demonstrated an ability to improve heart function and morphology. Pathological staining showed that overexpressing ATP5F1A could reduce fibrosis and cardiomyocyte size in the heart failure mouse model.

CONCLUSIONS

The present results of single-nucleus RNA sequencing and heart failure mouse model indicated that ATP5F1A could mediate CRR and supported the development of therapeutics for overexpressing ATP5F1A in promoting CRR.

MIF and CD74 as Emerging Biomarkers for Immune Checkpoint Blockade Therapy

Immune checkpoint blockade (ICB) therapy is used to treat a wide range of cancers; however, some patients are at risk of developing treatment resistance and/or immune-related adverse events (irAEs). Thus, there is a great need for the identification of reliable predictive biomarkers for response and toxicity. The cytokine MIF (macrophage migration inhibitory factor) and its cognate receptor CD74 are intimately connected with cancer progression and have previously been proposed as prognostic biomarkers for patient outcome in various cancers, including solid tumors such as malignant melanoma. Here, we assess their potential as predictive biomarkers for response to ICB therapy and irAE development. We provide a brief overview of their function and roles in the context of cancer and autoimmune disease. We also review the evidence showing that MIF and CD74 may be of use as predictive biomarkers of patient response to ICB therapy and irAE development. We also highlight that careful consideration is required when assessing the potential of serum MIF levels as a biomarker due to its reported circadian expression in human plasma. Finally, we suggest future directions for the establishment of MIF and CD74 as predictive biomarkers for ICB therapy and irAE development to guide further research in this field.

Blocking the MIF-CD74 axis augments radiotherapy efficacy for brain metastasis in NSCLC via synergistically promoting microglia M1 polarization

BACKGROUND

Brain metastasis is one of the main causes of recurrence and death in non-small cell lung cancer (NSCLC). Although radiotherapy is the main local therapy for brain metastasis, it is inevitable that some cancer cells become resistant to radiation. Microglia, as macrophages colonized in the brain, play an important role in the tumor microenvironment. Radiotherapy could activate microglia to polarize into both the M1 and M2 phenotypes. Therefore, searching for crosstalk molecules within the microenvironment that can specifically regulate the polarization of microglia is a potential strategy for improving radiation resistance.

METHODS

We used databases to detect the expression of MIF in NSCLC and its relationship with prognosis. We analyzed the effects of targeted blockade of the MIF/CD74 axis on the polarization and function of microglia during radiotherapy using flow cytometry. The mouse model of brain metastasis was used to assess the effect of targeted blockade of MIF/CD74 axis on the growth of brain metastasis.

RESULT

Our findings reveals that the macrophage migration inhibitory factor (MIF) was highly expressed in NSCLC and is associated with the prognosis of NSCLC. Mechanistically, we demonstrated CD74 inhibition reversed radiation-induced AKT phosphorylation in microglia and promoted the M1 polarization in combination of radiation. Additionally, blocking the MIF-CD74 interaction between NSCLC and microglia promoted microglia M1 polarization. Furthermore, radiation improved tumor hypoxia to decrease HIF-1α dependent MIF secretion by NSCLC. MIF inhibition enhanced radiosensitivity for brain metastasis via synergistically promoting microglia M1 polarization in vivo.

CONCLUSIONS

Our study revealed that targeting the MIF-CD74 axis promoted microglia M1 polarization and synergized with radiotherapy for brain metastasis in NSCLC.

Macrophage Migration Inhibitory Factor (MIF) and D-Dopachrome Tautomerase (DDT): Pathways to Tumorigenesis and Therapeutic Opportunities

Discovered as inflammatory cytokines, MIF and DDT exhibit widespread expression and have emerged as critical mediators in the response to infection, inflammation, and more recently, in cancer. In this comprehensive review, we provide details on their structures, binding partners, regulatory mechanisms, and roles in cancer. We also elaborate on their significant impact in driving tumorigenesis across various cancer types, supported by extensive in vitro, in vivo, bioinformatic, and clinical studies. To date, only a limited number of clinical trials have explored MIF as a therapeutic target in cancer patients, and DDT has not been evaluated. The ongoing pursuit of optimal strategies for targeting MIF and DDT highlights their potential as promising antitumor candidates. Dual inhibition of MIF and DDT may allow for the most effective suppression of canonical and non-canonical signaling pathways, warranting further investigations and clinical exploration.

Insight into NSCLC through novel analysis of gene interactions and characteristics

Around 80 to 85% of all lung cancers are non-small cell lung cancer (NSCLC). Previous research has aimed at exploring the genetic basis of NSCLC through individual approaches, but studies have yet to investigate the results of combining them. Here we show that analyzing NSCLC genetics through three approaches simultaneously creates unique insights into our understanding of the disease. Through a combination of previous research and bioinformatics tools, we determined 35 NSCLC candidate genes. We analyzed these genes in 3 different approaches. First, we found the gene fusions between these candidate genes. Second, we found the common superfamilies between genes. Finally, we identified mutational signatures that are possibly associated with NSCLC. Each approach has its individual, unique results. Fusion relationships identify specific gene fusion targets, common superfamilies identify possible avenues to determine novel target genes, and identifying NSCLC associated mutational signatures has diagnostic and prognostic benefits. Combining the approaches, we found that gene CD74 has significant fusion relationships, but it has no association with the other two approaches, suggesting that CD74 is associated with NSCLC mainly because of its fusion relationships. Targeting the gene fusions of CD74 may be an alternative NSCLC treatment. This genetic analysis has indeed created unique insight into NSCLC genes. Both the results from each of the approaches separately and combined allow pursuit of more effective treatment strategies for this cancer. The methodology presented can also apply to other cancers, creating insights that current analytical methods could not find.

CD74 as a prognostic and M1 macrophage infiltration marker in a comprehensive pan-cancer analysis

CD74 is a type-II transmembrane glycoprotein that has been linked to tumorigenesis. However, this association was based only on phenotypic studies, and, to date, no in-depth mechanistic studies have been conducted. In this study, combined with a multi-omics study, CD74 levels were significantly upregulated in most cancers relative to normal tissues and were found to be predictive of prognosis. Elevated CD74 expression was associated with reduced levels of mismatch-repair genes and homologous repair gene signatures in over 10 tumor types. Multiple fluorescence staining and bulk, spatial, single-cell transcriptional analyses indicated its potential as a marker for M1 macrophage infiltration in pan-cancer. In addition, CD74 expression was higher in BRCA patients responsive to conventional chemotherapy and was able to predict the prognosis of these patients. Potential CD74-activating drugs (HNHA and BRD-K55186349) were identified through molecular docking to CD74. The findings indicate activation of CD74 may have potential in tumor immunotherapy.

Lack of clinical utility of serum macrophage migration inhibitory factor (MIF) for monitoring therapy response and estimating prognosis in advanced lung cancer

BACKGROUND

Lung cancer is a major burden to global health and is still among the most frequent and most lethal malignant diseases. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in a variety of processes including tumorigenesis, formation of a tumor microenvironment and metastasis. It is therefore a potential prognostic biomarker in malignant diseases.

OBJECTIVE

In this study, we investigated the applicability of MIF in serum samples as a biomarker in lung cancer.

METHODS

In a retrospective approach, we analyzed the sera of 79 patients with non-small-cell lung cancer (NSCLC) and 14 patients with small-cell lung cancer (SCLC) before the start of chemotherapy, as well as before the second and third chemotherapy cycle, respectively. Serum MIF levels were measured using a sandwich immunoassay with a sulfo-tag-labelled detection antibody, while pro-gastrin releasing peptide (proGRP) levels were determined with an enzyme-linked immunosorbent assay.

RESULTS

No difference in serum MIF levels between responders and non-responders to chemotherapy was observed at all time points, while proGRP levels were significantly lower in responders before the second chemotherapy cycle (p = 0.012). No differences in biomarker levels depending on the histopathological classification of NSCLC patients was found. Moreover, in ROC curve analyses MIF was not able to distinguish between responders and non-responders to therapy. proGRP could differentiate between responders and non-responders before the second chemotherapy cycle (p = 0.015) with sensitivities of 43% at 90% and 95% specificity, respectively. Likewise, proGRP yielded significantly longer survival times of patients with low proGRP concentrations before the second chemotherapy cycle (p = 0.015) in Kaplan-Meier analyses, yet MIF showed no significant differences in survival times at all time points. Comparison with the biomarkers CEA and CYFRA 21-1 in the same cohort showed that these established biomarkers clearly performed superior to MIF and proGRP.

CONCLUSIONS

From the present results, there is no indication that serum MIF may serve as a biomarker in prognosis and monitoring of response to therapy in lung cancer. Limitations of this study include its retrospective design, the inclusion of a larger NSCLC and a smaller SCLC subgroup, the classical chemotherapeutic treatment, the use of a non-diagnostic immunoassay (RUO-test) for MIF measurement and the lack of a validation cohort. Strengths of the study are its highly standardized procedures concerning sample collection, preanalytic treatment, measurements and quality control of the laboratory assays.

Analysis of CD74 Occurrence in Oncogenic Fusion Proteins

CD74 is a type II cell surface receptor found to be highly expressed in several hematological and solid cancers, due to its ability to activate pathways associated with tumor cell survival and proliferation. Over the past 16 years, CD74 has emerged as a commonly detected fusion partner in multiple oncogenic fusion proteins. Studies have found CD74 fusion proteins in a range of cancers, including lung adenocarcinoma, inflammatory breast cancer, and pediatric acute lymphoblastic leukemia. To date, there are five known CD74 fusion proteins, CD74-ROS1, CD74-NTRK1, CD74-NRG1, CD74-NRG2α, and CD74-PDGFRB, with a total of 16 different variants, each with unique genetic signatures. Importantly, the occurrence of CD74 in the formation of fusion proteins has not been well explored despite the fact that ROS1 and NRG1 families utilize CD74 as the primary partner for the formation of oncogenic fusions. Fusion proteins known to be oncogenic drivers, including those of CD74, are typically detected and targeted after standard chemotherapeutic plans fail and the disease relapses. The analysis reported herein provides insights into the early intervention of CD74 fusions and highlights the need for improved routine assessment methods so that targeted therapies can be applied while they are most effective.

A single-cell atlas of West African lungfish respiratory system reveals evolutionary adaptations to terrestrialization

The six species of lungfish possess both lungs and gills and are the closest extant relatives of tetrapods. Here, we report a single-cell transcriptome atlas of the West African lungfish (Protopterus annectens). This species manifests the most extreme form of terrestrialization, a life history strategy to survive dry periods that can last for years, characterized by dormancy and reversible adaptive changes of the gills and lungs. Our atlas highlights the cell type diversity of the West African lungfish, including gene expression consistent with phenotype changes of terrestrialization. Comparison with terrestrial tetrapods and ray-finned fishes reveals broad homology between the swim bladder and lung cell types as well as shared and idiosyncratic changes of the external gills of the West African lungfish and the internal gills of Atlantic salmon. The single-cell atlas presented here provides a valuable resource for further exploration of the respiratory system evolution in vertebrates and the diversity of lungfish terrestrialization.

Single-cell RNA sequencing reveals distinct tumor microenvironment of ground glass nodules and solid nodules in lung adenocarcinoma

Introduction: Lung adenocarcinoma (LUAD) is the most prevalent lung cancer. LUAD presents as ground glass nodules (GGN) and solid nodules (SN) in imaging studies. GGN is an early type of LUAD with good prognosis. However, SN exhibits a more malignant behavior than GGN, including worse pathological staging and tumor prognosis. The mechanism leading to the different malignancy levels of GGN and SN remains elusive. Methods: Three patients with GGN and three patients with SN diagnosed with early LUAD were enrolled. The tumor samples were digested to a single-cell suspension and analyzed using 10× Genomic Single-cell ribonucleic acid sequences (scRNA-seq) techniques. Results: A total of 15,902 cells were obtained and classified into nine major types. The tumor microenvironment (TME) was subsequently described in detail. ScRNA-seq revealed that ribosome-related pathways and cell adhesion played similar but distinct roles in the two groups. SN also had more active cell proliferation, enriched cell cycle regulatory pathways, and severe inflammatory responses. Conclusion: We observed changes in the cellular composition and transcriptomic profile of GGN and SN. The study improved the understanding of the underlying mechanisms of lung carcinogenesis and contributed to lung cancer prevention and treatment.

The activity of cuproptosis pathway calculated by AUCell algorithm was employed to construct cuproptosis landscape in lung adenocarcinoma

Cuproptosis is a recently described copper-dependent cell death pathway. Consequently, there are still few studies on lung adenocarcinoma (LUAD)-related cuproptosis, and we aimed to deepen in this matter. In this study, data from 503 patients with lung cancer from the TCGA-LUAD cohort data collection and 11 LUAD single-cells from GSE131907 as well as from 10 genes associated with cuproptosis were analyzed. The AUCell R package was used to determine the copper-dependent cell death pathway activity for each cell subpopulation, calculate the CellChat score, and display cell communication for each cell subpopulation. The PROGENy score was calculated to show the scores of tumor-related pathways in different cell populations. GO and KEGG analyses were used to calculate pathway activity. Univariate COX and random forest analyses were used to screen prognosis-associated genes and construct models. The ssGSEA and xCell algorithms were used to calculate the immunocyte infiltration score. Based on data from the GDSC database, the drug sensitivity score was calculated using oncoPredict. Finally, in vitro experiments were performed to determine the role of TLE1, the most important gene in the prognostic model. The 11 LUAD single-cell samples were classified into 8 different cell populations, from which epithelial cells showed the highest copper-dependent cell death pathway activity. Epithelial cell subsets were significantly positively correlated with MAKP, hypoxia, and other pathways. In addition, cell subgroup communication showed highly active collagen and APP pathways. Using the Findmark algorithm, differentially expressed genes (DEGs) between epithelial and other cell types were identified. Combined with the bulk data in the TCGA-LUAD database, DEGs were enriched in pathways such as EGFR tyrosine kinase inhibitor resistance, Hippo signaling pathway, and tight junction. Subsequently, we selected 4 genes (out of 112) with prognostic significance, ANKRD29, RHOV, TLE1, and NPAS2, and used them to construct a prognostic model. The high- and low-risk groups, distinguished by the median risk score, showed significantly different prognoses. Finally, we chose TLE1 as a biomarker based on the relative importance score in the prognostic model. In vitro experiments showed that TLE1 promotes tumor proliferation and migration and inhibits apoptosis.

Prognostic role of CD74, CD10 and Ki-67 immunohistochemical expression in patients with diffuse malignant peritoneal mesothelioma: a retrospective study

BACKGROUND

Diagnosis and treatment of diffuse malignant peritoneal mesothelioma (DMPM) are still challenging. The aim of the present study was to explore the correlation between CD74, CD10, Ki-67 and clinicopathological parameters, and identify independent prognostic factors of DMPM.

METHODS

Seventy patients with pathologically proven DMPM were retrospectively reviewed. The expression of CD74, CD10 and Ki-67 in peritoneal tissues was detected by immunohistochemical analysis using standard avidin biotin complex (ABC) immunostaining technique. Kaplan-Meier survival analysis and multivariate Cox regression analyses were performed to assess prognostic factors. The nomogram based on the Cox hazards regression model was established. C-index and calibration curve were performed to evaluate the accuracy of nomogram models.

RESULTS

The median age of DMPM was 62.34 years, and the male-to-female ratio was 1: 1.80. CD74 expression was identified in 52 (74.29%) of 70 specimens, CD10 in 34 (48.57%) specimens, and higher Ki-67 in 33(47.14%) specimens. CD74 was negatively associated with asbestos exposure(r = -0.278), Ki-67(r = -0.251) and TNM stage(r = -0.313). All patients were effectively followed up in the survival analysis. Univariate analysis revealed that PCI, TNM stage, treatment, Ki-67, CD74 and ECOG PS were associated with DMPM prognosis. CD74 (HR = 0.65, 95%Cl:0.46-0.91, P = 0.014), Ki-67(HR = 2.09, 95%Cl:1.18-3.73, P = 0.012),TNM stage (HR = 1.89, 95%Cl:1.16-3.09, P = 0.011), ECOG PS(HR = 2.12, 95%Cl:1.06-4.25, P = 0.034), systemic chemotherapy (HR = 0.41, 95%Cl:0.21-0.82, P = 0.011) and intraperitoneal chemotherapy (HR = 0.34, 95%Cl:0.16-0.71, P = 0.004) were independent predictors by multivariate Cox analysis. The C‑index of the nomogram for predicting overall survival (OS) was 0.81. The OS calibration curve showed good agreement between nomogram-predicted and observed survival.

CONCLUSIONS

CD74, Ki-67, TNM stage, ECOG PS and treatment were independent factors affecting prognosis of DMPM. Reasonable chemotherapy treatment might improve the prognosis of patients. The proposed nomogram was a visual tool to effectively predict the OS of DMPM patients.

Tumor Necrosis Factor α-Dependent Lung Inflammation Promotes the Progression of Lung Adenocarcinoma Originating From Alveolar Type II Cells by Upregulating MIF-CD74

Lung adenocarcinoma is the most common type of lung cancer. We recently reported that inflammation-driven lung adenocarcinoma (IDLA) originates from alveolar type (AT)-II cells, which depend on major histocompatibility complex (MHC) class II to promote the expansion of regulatory T cells. The MHC class II-associated invariant chain (CD74) binds to the macrophage migration inhibitory factor (MIF), which is associated with promoting tumor growth and invasion. However, the role of MIF-CD74 in the progression of lung adenocarcinoma and the underlying mechanisms remain unclear. We aimed to explore the role of MIF-CD74 in the progression of lung adenocarcinoma and elucidate the mechanisms by which tumor necrosis (TNF)-α-mediated inflammation regulates CD74 and MIF expression in IDLA. In human lung adenocarcinoma, CD74 was upregulated on the surface of tumor cells originating from AT-II cells, which correlated positively with lymph node metastasis, tumor origin/nodal involvement/metastasis stage, and TNF-α expression. MIF interaction with CD74 promoted the proliferation and migration of A549 and H1299 cells in vitro. Using a urethane-induced IDLA mouse model, we observed that CD74 was upregulated in tumor cells and macrophages. MIF expression was upregulated in macrophages in IDLA. Blocking TNF-α-dependent inflammation downregulated CD74 expression in tumor cells and CD74 and MIF expression in macrophages in IDLA. Conditioned medium from A549 cells or activated mouse AT-II cells upregulated MIF in macrophages by secreting TNF-α. TNF-α-dependent lung inflammation contributes to the progression of lung adenocarcinoma by upregulating CD74 and MIF expression, and AT-II cells upregulate MIF expression in macrophages by secreting TNF-α. This study provides novel insights into the function of CD74 in the progression of IDLA.

Macrophage migration inhibitory factor family proteins are multitasking cytokines in tissue injury

The family of macrophage migration inhibitory factor (MIF) proteins in humans consist of MIF, its functional homolog D-dopachrome tautomerase (D-DT, also known as MIF-2) and the relatively unknown protein named DDT-like (DDTL). MIF is a pleiotropic cytokine with multiple properties in tissue homeostasis and pathology. MIF was initially found to associate with inflammatory responses and therefore established a reputation as a pro-inflammatory cytokine. However, increasing evidence demonstrates that MIF influences many different intra- and extracellular molecular processes important for the maintenance of cellular homeostasis, such as promotion of cellular survival, antioxidant signaling, and wound repair. In contrast, studies on D-DT are scarce and on DDTL almost nonexistent and their functions remain to be further investigated as it is yet unclear how similar they are compared to MIF. Importantly, the many and sometimes opposing functions of MIF suggest that targeting MIF therapeutically should be considered carefully, taking into account timing and severity of tissue injury. In this review, we focus on the latest discoveries regarding the role of MIF family members in tissue injury, inflammation and repair, and highlight the possibilities of interventions with therapeutics targeting or mimicking MIF family proteins.

CD74+ macrophages are associated with favorable prognosis and immune contexture in hepatocellular carcinoma

CD74 was initially thought to participate mainly in antigen presentation as an MHC class II chaperone. Recent studies have shown that CD74 plays an important role within the cell and throughout the immune system in a wide spectrum of neoplasms. However, the role of CD74 in hepatocellular carcinoma (HCC) remains elusive. In this study, HCC tissues from Zhongshan Hospital and data from The Cancer Genome Atlas (TCGA) were obtained and analyzed. Immunohistochemistry, flow cytometry, and single-cell RNA sequencing (scRNA-seq) were performed to detect the characteristics of CD74+ cells and explore their impact on the tumor microenvironment (TME) of HCC. Our data revealed that stromal CD74+ cell enrichment was associated with favorable prognosis in patients with HCC. CD74 was abundant in a large portion of HCC specimens and prominently distributed on stromal macrophages. scRNA-seq data also indicated that the pathways related to immune response were significantly upregulated in CD74+ macrophages. High infiltration of CD74+ macrophages was associated with increased infiltration of CD8+ cytotoxic T lymphocytes (CTLs) with enhanced effector functions in HCC. Besides, blocking CD74 weakened the antitumor activity and proliferation ability of CD8+ CTLs in HCC. Our findings highlight the critical role of CD74 in HCC. New drugs and antibodies targeting CD74 may be effective strategies for HCC therapy.

Single-Cell Transcriptomic Analysis Revealed a Critical Role of SPP1/CD44-Mediated Crosstalk Between Macrophages and Cancer Cells in Glioma

High-grade glioma is one of the most lethal human cancers characterized by extensive tumor heterogeneity. In order to identify cellular and molecular mechanisms that drive tumor heterogeneity of this lethal disease, we performed single-cell RNA sequencing analysis of one high-grade glioma. Accordingly, we analyzed the individual cellular components in the ecosystem of this tumor. We found that tumor-associated macrophages are predominant in the immune microenvironment. Furthermore, we identified five distinct subpopulations of tumor cells, including one cycling, two OPC/NPC-like and two MES-like cell subpopulations. Moreover, we revealed the evolutionary transition from the cycling to OPC/NPC-like and MES-like cells by trajectory analysis. Importantly, we found that SPP1/CD44 interaction plays a critical role in macrophage-mediated activation of MES-like cells by exploring the cell-cell communication among all cellular components in the tumor ecosystem. Finally, we showed that high expression levels of both SPP1 and CD44 correlate with an increased infiltration of macrophages and poor prognosis of glioma patients. Taken together, this study provided a single-cell atlas of one high-grade glioma and revealed a critical role of macrophage-mediated SPP1/CD44 signaling in glioma progression, indicating that the SPP1/CD44 axis is a potential target for glioma treatment.

Role of Atypical Chemokines and Chemokine Receptors Pathways in the Pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) represents a heightened inflammatory response in the lung generally resulting from tobacco smoking-induced recruitment and activation of inflammatory cells and/or activation of lower airway structural cells. Several mediators can modulate activation and recruitment of these cells, particularly those belonging to the chemokines (conventional and atypical) family. There is emerging evidence for complex roles of atypical chemokines and their receptors (such as high mobility group box 1 (HMGB1), antimicrobial peptides, receptor for advanced glycosylation end products (RAGE) or toll-like receptors (TLRs)) in the pathogenesis of COPD, both in the stable disease and during exacerbations. Modulators of these pathways represent potential novel therapies for COPD and many are now in preclinical development. Inhibition of only a single atypical chemokine or receptor may not block inflammatory processes because there is redundancy in this network. However, there are many animal studies that encourage studies for modulating the atypical chemokine network in COPD. Thus, few pharmaceutical companies maintain a significant interest in developing agents that target these molecules as potential antiinflammatory drugs. Antibody-based (biological) and small molecule drug (SMD)-based therapies targeting atypical chemokines and/or their receptors are mostly at the preclinical stage and their progression to clinical trials is eagerly awaited. These agents will most likely enhance our knowledge about the role of atypical chemokines in COPD pathophysiology and thereby improve COPD management.

Hsp90-stabilized MIF supports tumor progression via macrophage recruitment and angiogenesis in colorectal cancer

Macrophage migration inhibitory factor (MIF) is an upstream regulator of innate immunity, but its expression is increased in some cancers via stabilization with HSP90-associated chaperones. Here, we show that MIF stabilization is tumor-specific in an acute colitis-associated colorectal cancer (CRC) mouse model, leading to tumor-specific functions and selective therapeutic vulnerabilities. Therefore, we demonstrate that a Mif deletion reduced CRC tumor growth. Further, we define a dual role for MIF in CRC tumor progression. Mif deletion protects mice from inflammation-associated tumor initiation, confirming the action of MIF on host inflammatory pathways; however, macrophage recruitment, neoangiogenesis, and proliferative responses are reduced in Mif-deficient tumors once the tumors are established. Thus, during neoplastic transformation, the function of MIF switches from a proinflammatory cytokine to an angiogenesis promoting factor within our experimental model. Mechanistically, Mif-containing tumor cells regulate angiogenic gene expression via a MIF/CD74/MAPK axis in vitro. Clinical correlation studies of CRC patients show the shortest overall survival for patients with high MIF levels in combination with CD74 expression. Pharmacological inhibition of HSP90 to reduce MIF levels decreased tumor growth in vivo, and selectively reduced the growth of organoids derived from murine and human tumors without affecting organoids derived from healthy epithelial cells. Therefore, novel, clinically relevant Hsp90 inhibitors provide therapeutic selectivity by interfering with tumorigenic MIF in tumor epithelial cells but not in normal cells. Furthermore, Mif-depleted colonic tumor organoids showed growth defects compared to wild-type organoids and were less susceptible toward HSP90 inhibitor treatment. Our data support that tumor-specific stabilization of MIF promotes CRC progression and allows MIF to become a potential and selective therapeutic target in CRC.

Absence of CD74 Isoform at 41kDa Prevents the Heterotypic Associations between CD74 and CD44 in Human Lung Adenocarcinoma-derived Cells

Lung cancer is a leading cause of cancer-associated death in all over the globe. This study was undertaken to determine the expression and interaction of membrane-bound receptors CD74 and CD44 in human lung adenocarcinoma cells and their associated signaling was also attempted. Levels of CD74 and CD44 were studied in human lung adenocarcinoma-evolved cells A549 and H460. CD74-mediated downstream signaling was studied by the nuclear-transcription-factor NF-κB and prostaglandin E₂ (PGE₂) production. Flow-cytometric analysis showed that both CD74 and CD44 were perfectly expressed in A549 cells. Importantly, Western immunoblotting showed that A549 cells expressed only two isoforms of CD74 at 33 and 35 kDa but isoform at 41 kDa was absent. These results were verified in H460 cells. Confocal microscopy showed CD74 and CD44 was colocalized but heterotypic interaction between them was missing in both A549 and H460 cells. Activation of NF-κB and production of PGE₂ in human lung cancer cells were comparable with other cancer cells. In conclusion, this is the first study that shows A549 and H460 cells expressed two distinctive isoforms of CD74 but isoform at 41 kDa was absent. Due to the absence of this isoform, the direct physical interaction between them CD74 and CD44 was lacking. Furthermore, the data also demonstrated that lacking of direct physical interaction between CD74 and CD44 had no effect on NF-κB activation and PGE₂ production indicating that CD74-mediated downstream signaling occurs either through coreceptors or indirect interaction with CD44 in human lung cancer cells.

ABBREVIATION

CD: cluster of differentiation; SCLC: small cell lung cancer; NSCLC: nonsmall cell lung cancer; SCC: squamous cell carcinoma; ADC: adenocarcinoma; LCC: large cell carcinoma.

Concurrent Immunohistochemical Localization and Western Blot Analysis of the MIF Receptor, CD74, in Formalin-Fixed, Paraffin-Embedded Tissue

Archived, formalin-fixed, paraffin-embedded tissue provides a robust resource for assessing protein expression in a variety of complex tissue types. Immunohistochemical localization techniques allow one to identify proteins of interest in the different cell populations which compose these tissues, but quantitative comparison within and between samples is semiquantitative. In contrast, Western blot analysis provides a more quantitative assessment but without the ability to identify the cellular sources of expressed protein. Here we describe a dual approach using human endometrium to assess both the localization and quantitation of the macrophage migration inhibitory factor (MIF) receptor CD74 by immunohistochemical techniques and Western blotting.

The Proinflammatory and Proangiogenic Macrophage Migration Inhibitory Factor Is a Potential Regulator in Proliferative Diabetic Retinopathy

The macrophage migration inhibitory factor (MIF)/CD74 signaling pathway is strongly implicated in inflammation and angiogenesis. We investigated the expression of MIF and its receptor CD74 in proliferative diabetic retinopathy (PDR) to reveal a possible role of this pathway in the pathogenesis of PDR. Levels of MIF, soluble (s)CD74, soluble intercellular adhesion molecule-1 (sICAM-1) and vascular endothelial growth factor (VEGF) were significantly increased in the vitreous from patients with PDR compared to nondiabetic control samples. We detected significant positive correlations between the levels of MIF and the levels of sICAM-1 (r = 0.43; p = 0.001) and VEGF (r = 0.7; p < 0.001). Through immunohistochemical analysis of PDR epiretinal membranes, significant positive correlations were also found between microvessel density (CD31 expression) and the numbers of blood vessels expressing MIF (r = 0.56; p = 0.045) and stromal cells expressing MIF (r = 0.79; p = 0.001) and CD74 (r = 0.59; p = 0.045). Similar to VEGF, MIF was induced in Müller cells cultured under hypoxic conditions and MIF induced phosphorylation of ERK1/2 and VEGF production in Müller cells. Intravitreal administration of MIF in normal rats induced increased retinal vascular permeability and significant upregulation of phospho-ERK1/2, NF-κB, ICAM-1 and vascular cell adhesion molecule-1 expression in the retina. MIF induced migration and proliferation of human retinal microvascular endothelial cells. These results suggest that MIF/CD74 signaling is involved in PDR angiogenesis.

Knockdown of CD-74 in the Proliferative and Apoptotic Activity of Breast Cancer Cells

BACKGROUND

The cluster of differentiation (CD) 74 is known for its immunological functions and its elevated level was reported in various cancer cells.

AIM

The aim of the present study was to investigate the expression and potential roles of CD74 in the proliferative and apoptotic activity of breast cancer.

METHODS

Expression of CD74, macrophage migration inhibitory factor (MIF) and CD44 was assayed in CAMA-1 and MDA-MB-231 cell lines using flow cytometry. CD74 was knocked down using CD74 siRNA-transfection in CAMA-1, and MDA-MB-231 cells and proliferation and apoptosis were determined in the transfected breast cancer cells.

RESULTS

The data showed that CD74, MIF and CD44 were expressed in breast cancer cell lines and were associated with cell proliferation and apoptosis. Correlation analysis revealed that CD74 was positively correlated and colocalised with MIF on the cell-surface of CAMA-1 and MDA-MB-231. The knockdown of CD74 significantly reduced CAMA-1 and MDA-MB-231 cell proliferation and increased the level of apoptotic cells.

CONCLUSION

We concluded that the interactions of CD74 with MIF and CD74 with CD44 could be a potential tumour marker for breast cancer cells. Moreover, the level of co-expression of MIF and CD74 or CD44 could be a surrogate marker for the efficacy of anti-angiogenic drugs, particularly in breast cancer tumours. In short, the study revealed the potential roles of CD74 in the proliferation and apoptosis of breast cancer which may serve as a potential therapeutic target for breast cancer.

Expression of C-terminal ALK, RET, or ROS1 in lung cancer cells with or without fusion

Background

Genetic alterations, including mutation of epidermal growth factor receptor or v-Ki-ras2 kirsten rat sarcoma viral oncogene homolog and fusion of anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), or v-ros UR2 sarcoma virus oncogene homolog 1 (ROS1), occur in non-small cell lung cancers, and these oncogenic drivers are important biomarkers for targeted therapies. A useful technique to screen for these fusions is the detection of native carboxy-terminal (C-terminal) protein by immunohistochemistry; however, the effects of other genetic alterations on C-terminal expression is not fully understood. In this study, we evaluated whether C-terminal expression is specifically elevated by fusion with or without typical genetic alterations of lung cancer.

Methods

In 37 human lung cancer cell lines and four tissue specimens, protein and mRNA levels were measured by capillary western blotting and reverse transcription–PCR, respectively.

Results

Compared with the median of all 37 cell lines, mRNA levels at the C-terminus of all five of the fusion-positive cell lines tested (three ALK, one RET, and one ROS1) were elevated at least 2000-, 300-, or 2000-fold, respectively, and high C-terminal protein expression was detected. In an ALK fusion–positive tissue specimen, the mRNA and protein levels of C-terminal ALK were also markedly elevated. Meanwhile, in one of 36 RET fusion–negative cell lines, RET mRNA levels at the C-terminus were elevated at least 500-fold compared with the median of all 37 cell lines, and high C-terminal protein expression was detected despite the absence of RET fusion.

Conclusions

This study of 37 cell lines and four tissue specimens shows the detection of C-terminal ALK or ROS1 proteins could be a comprehensive method to determine ALK or ROS1 fusion, whereas not only the detection of C-terminal RET protein but also other methods would be needed to determine RET fusion.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5527-2) contains supplementary material, which is available to authorized users.

Immunophenotyping of the cluster of differentiation 74, migration inhibitory factor, and cluster of differentiation 44 expression on human breast cancer-derived cell lines

OBJECTIVE

Cluster of differentiation (CD) 74, CD44, and macrophage migration inhibitory factor (MIF) are well known for their immunological functions; however, it has been shown that recently, CD74, CD44, and MIF have a role in tumor and tumor progression. This study was undertaken to investigate the expression of CD74, MIF, and CD44 in breast cancer cells.

MATERIALS AND METHODS

The expression of CD74, MIF, and CD44 molecules on the breast cancer-derived cell lines CAMA-1, 3,4-methylenedioxyamphetamine (MDA)-MB-231, and MDA-MB-43 was determined by flow cytometry, western immunoblotting, and confocal microscope. To validate the study the studying expression of CD74, MIF, and CD44 on the normal breast cell line 266LDM, whole cell lysate obtained from adult normal breast tissue and normal breast tissue.

RESULTS

The results show that all breast cancer cells overexpress CD74 isoforms, MIF, and CD44, in contrast to the normal cell lines and normal breast tissues, which express only CD44 and MIF in low levels. The expression of CD74, MIF, and CD44 was studied in the immortalized normal breast luminal cell line 226LDM, normal breast tissues, and lysate to validate the study.

CONCLUSION

The data show, in this study, the evidence that breast cancer cell lines expressing three different isoforms of CD74. The results of the present study indicate a crucial role of CD74 in breast cancer cells along with MIF and CD44. The results also suggest that CAMA-1, MDA-MB-231, and MDA-MB-435 cells are poorly immunogenic, expressing low levels of HLA-A, B, and C and HLA-DR.

CD74 regulates complexity of tumor cell HLA class II peptidome in brain metastasis and is a positive prognostic marker for patient survival

Despite multidisciplinary local and systemic therapeutic approaches, the prognosis for most patients with brain metastases is still dismal. The role of adaptive and innate anti-tumor response including the Human Leukocyte Antigen (HLA) machinery of antigen presentation is still unclear. We present data on the HLA class II-chaperone molecule CD74 in brain metastases and its impact on the HLA peptidome complexity.We analyzed CD74 and HLA class II expression on tumor cells in a subset of 236 human brain metastases, primary tumors and peripheral metastases of different entities in association with clinical data including overall survival. Additionally, we assessed whole DNA methylome profiles including CD74 promoter methylation and differential methylation in 21 brain metastases. We analyzed the effects of a siRNA mediated CD74 knockdown on HLA-expression and HLA peptidome composition in a brain metastatic melanoma cell line.We observed that CD74 expression on tumor cells is a strong positive prognostic marker in brain metastasis patients and positively associated with tumor-infiltrating T-lymphocytes (TILs). Whole DNA methylome analysis suggested that CD74 tumor cell expression might be regulated epigenetically via CD74 promoter methylation. CD74high and TILhigh tumors displayed a differential DNA methylation pattern with highest enrichment scores for antigen processing and presentation. Furthermore, CD74 knockdown in vitro lead to a reduction of HLA class II peptidome complexity, while HLA class I peptidome remained unaffected.In summary, our results demonstrate that a functional HLA class II processing machinery in brain metastatic tumor cells, reflected by a high expression of CD74 and a complex tumor cell HLA peptidome, seems to be crucial for better patient prognosis.

Identification of differentially expressed inflammatory factors in Wilms tumors and their association with patient outcomes

The present study aimed to identify differentially expressed inflammatory factors observed in Wilms tumors (WT), and to investigate the association of these factors with clinical stage, pathological type, lymph node metastasis and vascular involvement of WT. Surface-enhanced laser desorption/ionization-time of flight mass spectrometry was performed to screen differentially expressed proteins among WT and normal tissue pairs. Upregulated proteins in WT were separated and purified by solid phase extraction and Tricine SDS-PAGE, respectively. Following in-gel digestion, the peptide mixture was subjected to liquid chromatography mass spectrometry to identify proteins on the basis of their amino acid sequences. Immunohistochemistry was used to confirm the expression of differentially expressed inflammatory proteins. Of the proteins that were upregulated in WT, two proteins with mass/charge (m/z) ratio of 12,138 and 13,462 were identified as macrophage migration inhibitory factor (MIF) and C-X-C motif ligand 7 (CXCL7) chemokine, respectively. The expression of these two proteins was increased in WT compared with adjacent normal tissues and normal renal tissues, and increased with increasing clinical stage. In addition, their expression was significantly increased in patients with unfavorable pathological type, lymph node metastasis and vascular involvement compared with the groups with favorable type, and without lymph node metastasis or vascular involvement (P<0.05). Increased pro-inflammatory MIF and CXCL7 expression in WT is closely associated with the clinical stage, pathological type, lymph node metastasis and vascular involvement, and may represent biomarkers for the clinical diagnosis of WT.

Expression of CD74 in invasive breast carcinoma: its relation to Nottingham Prognostic Index, hormone receptors, and HER2 immunoprofile

PURPOSE

To study the immunohistochemical expression of CD74 in series of invasive breast carcinomas classified according to their estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) immunoprofile and explore its correlation to Nottingham Prognostic Index (NPI) and tumor pathologic stage to determine if it has a prognostic value.

METHODS

A total of 160 cases of mammary carcinoma were classified broadly according to their ER, PR, and HER2 expression into luminal, HER2-positive, and triple-negative groups. The NPI was calculated and pathologic stage was recorded for each individual case and cases were classified into different prognostic groups. The CD74 expression was evaluated immunohistochemically and correlated to different prognostic variables.

RESULTS

The CD74 immunohistochemical expression in invasive breast carcinoma was significantly higher in triple-negative tumors, higher tumor grades, presence of lymph nodal metastasis, higher tumor stages, and higher NPI scores.

CONCLUSIONS

The CD74 might be a useful prognostic indicator predicting poor outcome of patients with breast carcinoma. Its consistent expression in triple-negative breast carcinomas points to the need of further studies to test the possibility if it can be targeted in treatment of breast carcinoma, especially in such groups.

Macrophage migration inhibitory factor, a role in COPD

Macrophage migration inhibitor factor (MIF) is a pluripotent cytokine associated with several different inflammatory conditions, but its role within lung inflammation and chronic obstructive pulmonary disease (COPD) is unclear. This study aimed to examine MIF in both stable COPD and during acute exacerbations (AECOPD). The study included 433 patients with COPD aged 41-76 and 325 individuals from the Bergen COPD cohort study who served as controls. All patients had an FEV1 of <80% predicted, FEV1/FVC ratio of <0.7, and a smoking history >10 pack-years. Serum levels of MIF were compared between the two groups at baseline, and for 149 patients, measurements were also carried out during AECOPD. Linear regression models were fitted with MIF as the outcome variable and adjusted for sex, age, body composition, smoking, and Charlson Comorbidity Score (CCS). Median MIF (interquartile range) in patients with COPD was 20.1 ng/ml (13.5-30.9) compared with 14.9 ng/ml (11.1-21.6) in controls (P < 0.01). MIF was bivariately associated with sex, body composition, and CCS (P < 0.05 for all). In the regression analyses, MIF was significantly higher in patients with COPD, coefficient 1.32 (P < 0.01) and 1.30 (P < 0.01) unadjusted and adjusted, respectively. In addition, in 149 patients during episodes of AECOPD, MIF was significantly elevated, with a median of 23.2 ng/ml (14.1-42.3) compared with measurements at stable disease of 19.3 ng/ml (12.4-31.3, P < 0.01). Serum levels of MIF were significantly higher in patients with COPD compared with controls. We also identified an additional increase in MIF levels during episodes of AECOPD.

The multifaceted roles of the invariant chain CD74--More than just a chaperone

The invariant chain (CD74) is well known for its essential role in antigen presentation by mediating assembly and subcellular trafficking of the MHCII complex. Beyond this, CD74 has also been implicated in a number of processes independent of MHCII. These include the regulation of endosomal trafficking, cell migration and cellular signalling as surface receptor of the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF). In several forms of cancer, CD74 is up-regulated and associated with enhanced proliferation and metastatic potential. In this review, an overview of the diverse biological functions of the CD74 protein is provided with a particular focus on how these may be regulated. In particular, proteolysis of CD74 will be discussed as a central mechanism to control the actions of this important protein at different levels.

Processing of CD74 by the Intramembrane Protease SPPL2a Is Critical for B Cell Receptor Signaling in Transitional B Cells

The invariant chain (CD74), a chaperone in MHC class II-mediated Ag presentation, is sequentially processed by different endosomal proteases. We reported recently that clearance of the final membrane-bound N-terminal fragment (NTF) of CD74 is mediated by the intramembrane protease signal peptide peptidase-like (SPPL)2a, a process critical for B cell development. In mice, SPPL2a deficiency provokes the accumulation of this NTF in endocytic vesicles, which leads to a B cell maturation arrest at the transitional 1 stage. To define the underlying mechanism, we analyzed the impact of SPPL2a deficiency on signaling pathways involved in B cell homeostasis. We demonstrate that tonic as well as BCR-induced activation of the PI3K/Akt pathway is massively compromised in SPPL2a(-/-) B cells and identify this as major cause of the B cell maturation defect in these mice. Altered BCR trafficking induces a reduction of surface IgM in SPPL2a-deficient B cells, leading to a diminished signal transmission via the BCR and the tyrosine kinase Syk. We provide evidence that in SPPL2a(-/-) mice impaired BCR signaling is to a great extent provoked by the accumulating CD74 NTF, which can interact with the BCR and Syk, and that impaired PI3K/Akt signaling and reduced surface IgM are not directly linked processes. In line with disturbances in PI3K/Akt signaling, SPPL2a(-/-) B cells show a dysregulation of the transcription factor FOXO1, causing elevated transcription of proapoptotic genes. We conclude that SPPL2a-mediated processing of CD74 NTF is indispensable to maintain appropriate levels of tonic BCR signaling to promote B cell maturation.

Role of macrophage migration inhibitory factor in age-related lung disease

The prevalence of many common respiratory disorders, including pneumonia, chronic obstructive lung disease, pulmonary fibrosis, and lung cancer, increases with age. Little is known of the host factors that may predispose individuals to such diseases. Macrophage migration inhibitory factor (MIF) is a potent upstream regulator of the immune system. MIF is encoded by variant alleles that occur commonly in the population. In addition to its role as a proinflammatory cytokine, a growing body of literature demonstrates that MIF influences diverse molecular processes important for the maintenance of cellular homeostasis and may influence the incidence or clinical manifestations of a variety of chronic lung diseases. This review highlights the biological properties of MIF and its implication in age-related lung disease.

Macrophage migration inhibitory factor (MIF) enzymatic activity and lung cancer

The cytokine macrophage migration inhibitory factor (MIF) possesses unique tautomerase enzymatic activity, which contributes to the biological functional activity of MIF. In this study, we investigated the effects of blocking the hydrophobic active site of the tautomerase activity of MIF in the pathogenesis of lung cancer. To address this, we initially established a Lewis lung carcinoma (LLC) murine model in Mif-KO and wild-type (WT) mice and compared tumor growth in a knock-in mouse model expressing a mutant MIF lacking enzymatic activity (Mif (P1G)). Primary tumor growth was significantly attenuated in both Mif-KO and Mif (P1G) mice compared with WT mice. We subsequently undertook a structure-based, virtual screen to identify putative small molecular weight inhibitors specific for the tautomerase enzymatic active site of MIF. From primary and secondary screens, the inhibitor SCD-19 was identified, which significantly attenuated the tautomerase enzymatic activity of MIF in vitro and in biological functional screens. In the LLC murine model, SCD-19, given intraperitoneally at the time of tumor inoculation, was found to significantly reduce primary tumor volume by 90% (p < 0.001) compared with the control treatment. To better replicate the human disease scenario, SCD-19 was given when the tumor was palpable (at d 7 after tumor inoculation) and, again, treatment was found to significantly reduce tumor volume by 81% (p < 0.001) compared with the control treatment. In this report, we identify a novel inhibitor that blocks the hydrophobic pocket of MIF, which houses its specific tautomerase enzymatic activity, and demonstrate that targeting this unique active site significantly attenuates lung cancer growth in in vitro and in vivo systems.

MMP7-mediated cleavage of nucleolin at Asp255 induces MMP9 expression to promote tumor malignancy

Nucleolin (NCL) participates in DNA transcription, ribosomal biogenesis and the regulation of RNA stability. However, the contribution of NCL to tumor development is still not clear. Herein, we found that NCL expression correlated with poor prognosis in lung cancer patients. Overexpressed NCL was predominantly cleaved to C-terminal truncated NCL (TNCL). In lung cancer formation, activation of the epidermal growth factor receptor pathway induced NCL expression, and also the expression of matrix metalloproteinase (MMP) 7, which then cleaved NCL at Asp255 to generate TNCL of 55 kDa. TNCL increased the expression of several oncogenes, including MMP9, anaplastic lymphoma kinase (ALK), HIF1a and CBLB, and decreased the expression of tumor suppressors including BRD4, PCM1, TFG and KLF6 by modulating mRNA stability through binding to the 3'-untranslated regions of their transcripts, thus ultimately enhancing metastasis activity. In conclusion, this study identified a novel role of the cleavage form of NCL generated by MMP7 in stabilizing MMP9 mRNA. We also provide a new insight that MMP7 not only cleaves the extracellular matrix to promote tumor invasion but also cleaves NCL, which augment oncogenesis. Blocking NCL cleavage may provide a useful new strategy for lung cancer therapy.

Stromal-dependent tumor promotion by MIF family members

Solid tumors are composed of a heterogeneous population of cells that interact with each other and with soluble and insoluble factors that, when combined, strongly influence the relative proliferation, differentiation, motility, matrix remodeling, metabolism and microvessel density of malignant lesions. One family of soluble factors that is becoming increasingly associated with pro-tumoral phenotypes within tumor microenvironments is that of the migration inhibitory factor family which includes its namesake, MIF, and its only known family member, D-dopachrome tautomerase (D-DT). This review seeks to highlight our current understanding of the relative contributions of a variety of immune and non-immune tumor stromal cell populations and, within those contexts, will summarize the literature associated with MIF and/or D-DT.

MIF Receptor CD74 is Restricted to Microglia/Macrophages, Associated with a M1-Polarized Immune Milieu and Prolonged Patient Survival in Gliomas

The macrophage migration inhibitory factor (MIF) receptor CD74 is overexpressed in various neoplasms, mainly in hematologic tumors, and currently investigated in clinical studies. CD74 is quickly internalized and recycles after antibody binding, therefore it constitutes an attractive target for antibody-based treatment strategies. CD74 has been further described as one of the most up-regulated molecules in human glioblastomas. To assess the potential relevance for anti-CD74 treatment, we determined the cellular source and clinicopathologic relevance of CD74 expression in human gliomas by immunohistochemistry, immunofluorescence, immunoblotting, cell sorting analysis and quantitative polymerase chain reaction (qPCR). Furthermore, we fractionated glioblastoma cells and glioma-associated microglia/macrophages (GAMs) from primary tumors and compared CD74 expression in cellular fractions with whole tumor lysates. Our results show that CD74 is restricted to GAMs in vivo, while being absent in tumor cells, the latter strongly expressing its ligand MIF. Most interestingly, a higher amount of CD74-positive GAMs was associated with beneficial patient survival constituting an independent prognostic parameter and with an anti-tumoral M1 polarization. In summary, CD74 expression in human gliomas is restricted to GAMs and positively associated with patient survival. In conclusion, CD74 represents a positive prognostic marker most probably because of its association with an M1-polarized immune milieu in high-grade gliomas.

MIF family members cooperatively inhibit p53 expression and activity

The tumor suppressor p53 is induced by genotoxic stress in both normal and transformed cells and serves to transcriptionally coordinate cell cycle checkpoint control and programmed cell death responses. Macrophage migration inhibitory factor (MIF) is an autocrine and paracrine acting cytokine/growth factor that promotes lung adenocarcinoma cell motility, anchorage-independence and neo-angiogenic potential. Several recent studies indicate that the only known homolog of MIF, D-dopachrome tautomerase (D-DT - also referred to as MIF-2), has functionally redundant activities with MIF and cooperatively promotes MIF-dependent pro-tumorigenic phenotypes. We now report that MIF and D-DT synergistically inhibit steady state p53 phosphorylation, stabilization and transcriptional activity in human lung adenocarcinoma cell lines. The combined loss of MIF and D-DT by siRNA leads to dramatically reduced cell cycle progression, anchorage independence, focus formation and increased programmed cell death when compared to individual loss of MIF or D-DT. Importantly, p53 mutant and p53 null lung adenocarcinoma cell lines were only nominally rescued from the cell growth effects of MIF/D-DT combined deficiency suggesting only a minor role for p53 in these transformed cell growth phenotypes. Finally, increased p53 activation was found to be independent of aberrantly activated AMP-activated protein kinase (AMPK) that occurs in response to MIF/D-DT-deficiency but is dependent on reactive oxygen species (ROS) that mediate aberrant AMPK activation in these cells. Combined, these findings suggest that both p53 wildtype and mutant human lung adenocarcinoma tumors rely on MIF family members for maximal cell growth and survival.

Involvement of macrophage migration inhibitory factor and its receptor (CD74) in human breast cancer

Macrophage migration inhibitory factor (MIF) and its receptor CD74 appear to be involved in tumorigenesis. We evaluated, by immunohistochemical staining, the tissue expression and distribution of MIF and CD74 in serial sections of human invasive breast cancer tumor specimens. The serum MIF level was also determined in breast cancer patients. We showed a significant increase in serum MIF average levels in breast cancer patients compared to healthy individuals. MIF tissue expression, quantified by a modified Allred score, was strongly increased in carcinoma compared to tumor-free specimens, in the cancer cells and in the peritumoral stroma, with fibroblasts the most intensely stained. We did not find any significant correlation with histoprognostic factors, except for a significant inverse correlation between tumor size and MIF stromal positivity. CD74 staining was heterogeneous and significantly decreased in cancer cells but increased in the surrounding stroma, namely in lymphocytes, macrophages and vessel endothelium. There was no significant variation according to classical histoprognostic factors, except that CD74 stromal expression was significantly correlated with triple-negative receptor (TRN) status and the absence of estrogen receptors. In conclusion, our data support the concept of a functional role of MIF in human breast cancer. In addition to auto- and paracrine effects on cancer cells, MIF could contribute to shape the tumor microenvironment leading to immunomodulation and angiogenesis. Interfering with MIF effects in breast tumors in a therapeutic perspective remains an attractive but complex challenge. Level of co-expression of MIF and CD74 could be a surrogate marker for efficacy of anti-angiogenic drugs, particularly in TRN breast cancer tumor.

Involvement of CD74 in head and neck squamous cell carcinomas

PURPOSE

While macrophage migration inhibitory factor (MIF) has been extensively studied in the context of inflammation and inflammatory disorders, less work has been devoted to its involvement in cancer, notably in neoplastic progression. In a previous study, we have found evidence that MIF plays a role in head and neck squamous cell carcinomas (HNSCC). The current investigations were undertaken in order to estimate the importance of the MIF receptor, CD74 in the progression of HNSCC.

METHODS AND RESULTS

In a cohort of 46 cases of oral cavity carcinomas, immunohistochemical staining revealed an increase in CD74 expression during progression from benign lesions to carcinoma. As shown by cell culture experiments using squamous carcinoma cell line (SCCVII) transduced with anti-CD74 shRNA, the amount of cell-produced VEGF was lower in SCCVII CD74KD cell line compared with control SCCVII CD74sc cell line, suggesting that CD74 could be implicated in angiogenesis in vivo. Furthermore, knockdown of CD74 decreased proliferation of SCCVII cells in vitro. The migration of SCCVII cells, as well as the cell secretion of matrix metallopeptidase 9, was also negatively affected by CD74 knockdown. These observations in vitro were confirmed in an orthotopic mouse model of SCC where tumors produced by SCCVII CD74KD cell inoculation were found to grow more slowly than tumors generated by SCCVII CD74sc cells.

CONCLUSION

The clinical observations and experimental data reported here suggest that CD74, as well as MIF, plays a pivotal role in HNSCC progression.

MIF antagonist (CPSI-1306) protects against UVB-induced squamous cell carcinoma

Macrophage migration inhibitory factor (MIF) is a homotrimeric proinflammatory cytokine implicated in chronic inflammatory diseases and malignancies, including cutaneous squamous cell carcinomas (SCC). To determine whether MIF inhibition could reduce UVB light-induced inflammation and squamous carcinogenesis, a small-molecule MIF inhibitor (CPSI-1306) was utilized that disrupts homotrimerization. To examine the effect of CPSI-1306 on acute UVB-induced skin changes, Skh-1 hairless mice were systemically treated with CPSI-1306 for 5 days before UVB exposure. In addition to decreasing skin thickness and myeloperoxidase (MPO) activity, CPSI-1306 pretreatment increased keratinocyte apoptosis and p53 expression, decreased proliferation and phosphohistone variant H2AX (γ-H2AX), and enhanced repair of cyclobutane pyrimidine dimers. To examine the effect of CPSI-1306 on squamous carcinogenesis, mice were exposed to UVB for 10 weeks, followed by CPSI-1306 treatment for 8 weeks. CPSI-1306 dramatically decreased the density of UVB-associated p53 foci in non-tumor-bearing skin while simultaneously decreasing the epidermal Ki67 proliferation index. In addition to slowing the rate of tumor development, CPSI-1306 decreased the average tumor burden per mouse. Although CPSI-1306-treated mice developed only papillomas, nearly a third of papillomas in vehicle-treated mice progressed to microinvasive SCC. Thus, MIF inhibition is a promising strategy for prevention of the deleterious cutaneous effects of acute and chronic UVB exposure.

IMPLICATIONS

Macrophage migration inhibitory factor is a viable target for the prevention of UVB-induced cutaneous SSCs.

CD74: a new prognostic factor for patients with malignant pleural mesothelioma

Background:

The pro-inflammatory cytokine migration inhibitory factor (MIF) and its receptor CD74 have been proposed as possible therapeutic targets in several cancers. We studied the expression of MIF and CD74 together with calretinin in specimens of malignant pleural mesothelioma (MPM), correlating their expression levels with clinico-pathologic parameters, in particular overall survival (OS).

Methods:

Migration inhibitory factor, CD74, and calretinin immunoreactivity were investigated in a tissue microarray of 352 patients diagnosed with MPM. Protein expression intensities were semiquantitatively scored in the tumour cells and in the peritumoral stroma. Markers were matched with OS, age, gender, and histological subtype.

Results:

Clinical data from 135 patients were available. Tumour cell expressions of MIF and CD74 were observed in 95% and 98% of MPM specimens, respectively, with a homogenous distribution between the different histotypes. CD74 (P<0.001) but not MIF overexpression (P=0.231) emerged as an independent prognostic factor for prolonged OS. High expression of tumour cell calretinin correlated with the epithelioid histotype and was also predictive of longer OS (P<0.001). When compared with previously characterised putative epithelial-to-mesenchymal transition markers, CD74 correlated positively with tumoral PTEN and podoplanin expressions, but was inversely related with periostin expression.

Conclusions:

High expression of CD74 is an independent prognostic factor for prolonged OS in mesothelioma patients.

Effect of CD74 on the prognosis of patients with resectable pancreatic cancer

BACKGROUND

CD74 is known as a type II transmembrane glycoprotein that is associated with the major histocompatibility complex class II alpha and beta chains. Recent studies have demonstrated that the expression of CD74 is also linked to some forms of tumors. The present study was to assess the effect of CD74 expression on the prognosis of resectable pancreatic ductal adenocarcinoma (PDAC).

METHODS

Forty-six patients who had received a curative resection of primary PDAC and postoperative chemotherapy were included in this study. Immunohistochemical staining was conducted of CD74 on paraffin-embedded tumor sample slices. The patients were grouped according to CD74 staining: CD74 (-): CD74 positive tumor cells<25%; and CD74 (+): CD74 positive tumor cells ≥25%. The correlation of CD74 expression level with clinicopathological features and cumulative survival rate was calculated.

RESULTS

The numbers of CD74 (+) and (-) patients were 32 and 14, respectively. CD74 (+) patients showed a high rate of perineural invasion (P=0.007). The 3- and 5-year cumulative survival rates of CD74 (-) patients were significantly higher than those of CD74 (+) patients (62% and 41% vs 9% and 0%, P=0.000). Multivariate analysis showed that CD74 expression and lymphatic permeation were the independent prognostic indicators.

CONCLUSIONS

The overexpression of CD74 is a key factor associated with perineural invasion. Lower-stage (I and II) PDAC patients with CD74 overexpression have a poor prognosis even if they receive a curative resection. CD74 can be used as a prognostic indicator for resectable PDAC.

Novel association between CD74 polymorphisms and hematologic toxicity in patients with NSCLC after platinum-based chemotherapy

BACKGROUND

Platinum-based chemotherapy regimens can cause DNA damage. Macrophage migration inhibitory factor (MIF) plays an important role in the regulation of the cell cycle by either controlling the activity of the SKP1-Cullin/Cdc53-F-box protein ubiquitin ligase (SCF) complex or activating its receptor, CD74.

PATIENTS AND METHODS

We used a pathway-based approach to investigate the association between genetic polymorphisms in MIF-pathway genes and the outcomes of platinum-based chemotherapy in advanced non-small-cell lung cancer (NSCLC). We used iSelect 24×1 HD BeadChip (Illumina, Inc, San Diego, CA) to genotype 32 tag and potentially functional single nucleotide polymorphisms (SNPs) of 8 selected genes and evaluated their associations with different outcomes for 1004 patients with advanced NSCLC treated with platinum-based chemotherapy. In particular, gastrointestinal toxicity and hematologic toxicity were analyzed for associations with specific genotypes, alleles, and haplotypes.

RESULTS

Two polymorphisms of CD74, rs2748249 (C/A) and rs1560661 (A/G), were significantly associated with hematologic toxicity. Carrying an A allele in rs2748249 was associated with higher hematologic toxicity (odds ratio [OR], 1.72; 95% confidence interval [CI], 1.24-2.39; P = .001) and carrying a G allele in rs1560661 was associated with lower hematologic toxicity (OR, 0.42; 95% CI, 0.25-0.70; P = .00099) compared with the wild type. Haplotype analysis revealed that the patients with the CG haplotype (consisting of rs2748249 and rs1560661) had reduced hematologic toxicity compared with patients with other haplotypes (OR, 0.70; 95% CI, 0.56-0.87; P = .0013). The binding domain shared by 3 transcription factors (activator protein-2α [AP-2α], progesterone response A/B, and TFII-I) comprised the 2 SNPs that may be involved in the regulation of CD74-related B-cell survival.

CONCLUSION

Our study is the first to suggest, to our knowledge, that polymorphisms in CD74 might be a marker of lower hematologic toxicity for patients with advanced NSCLC receiving platinum-based chemotherapy.

Pharmacological inhibition of macrophage migration inhibitory factor interferes with the proliferation and invasiveness of squamous carcinoma cells

Recent clinical observations and experimental studies of our group indicate that macrophage migration inhibitory factor (MIF) may contribute to tumor progression in head and neck squamous cell carcinomas (HNSCC). The present study was undertaken to examine the effects of the irreversible MIF inhibitor 4-iodo-6-phenylpyrimidine (4-IPP) on proliferation and invasiveness of the squamous carcinoma cell line SCCVII. Cell counting, crystal violet assay and flow cytometry were used to analyze the effects of 4-IPP on SCCVII cell growth. The impact of 4-IPP on cell invasiveness was assessed by Boyden chamber assay. Knockdown of the MIF receptor CD74 was achieved by transduction with lentiviral vectors encoding anti-CD74 shRNAs. As shown by immunofluorescence staining, SCCVII cells express both MIF and CD74. Decreased MIF immunoreactivity as a result of exposure to 4-IPP suggested a covalent modification of the cytokine. 4-IPP inhibited SCCVII cell proliferation and invasiveness. Moreover, the cytostatic effect of 4-IPP was enhanced by CD74 knockdown. The inhibitory effects of 4-IPP on cell proliferation and invasiveness strongly suggest that MIF is involved in proliferative activity and invasive properties of squamous carcinoma cells. In conclusion, MIF inhibition may open possibilities for target-directed treatment of head and neck squamous cell carcinoma.