Mesenchymal COX2-PG secretome engages NR4A-WNT signalling axis in haematopoietic progenitors to suppress anti-leukaemia immunity

The multi-CDK inhibitor dinaciclib reverses bromo- and extra-terminal domain (BET) inhibitor resistance in acute myeloid leukemia via inhibition of Wnt/β-catenin signaling

Acute myeloid leukemia (AML) is a highly aggressive hematologic cancer with poor survival across a broad range of molecular subtypes. Development of efficacious and well-tolerable therapies encompassing the range of mutations that can arise in AML remains an unmet need. The bromo- and extra-terminal domain (BET) family of proteins represents an attractive therapeutic target in AML due to their crucial roles in many cellular functions, regardless of any specific mutation. Many BET inhibitors (BETi) are currently in pre-clinical and early clinical development, but acquisition of resistance continues to remain an obstacle for the drug class. Novel methods to circumvent this development of resistance could be instrumental for the future use of BET inhibitors in AML, both as monotherapy and in combination. To date, many investigations into possible drug combinations of BETi with CDK inhibitors have focused on CDK9, which has a known physical and functional interaction with the BET protein BRD4. Therefore, we wished to investigate possible synergy and additive effects between inhibitors of these targets in AML. Here, we describe combination therapy with the multi-CDK inhibitor dinaciclib and the BETi PLX51107 in pre-clinical models of AML. Dinaciclib and PLX51107 demonstrate additive effects in AML cell lines, primary AML samples, and in vivo. Further, we demonstrate novel activity of dinaciclib through inhibition of the canonical/β-catenin dependent Wnt signaling pathway, a known resistance mechanism to BETi in AML. We show dinaciclib inhibits Wnt signaling at multiple levels, including downregulation of β-catenin, the Wnt co-receptor LRP6, as well as many Wnt pathway components and targets. Moreover, dinaciclib sensitivity remains unaffected in a setting of BET resistance, demonstrating similar inhibitory effects on Wnt signaling when compared to BET-sensitive cells. Ultimately, our results demonstrate rationale for combination CDKi and BETi in AML. In addition, our novel finding of Wnt signaling inhibition could have potential implications in other cancers where Wnt signaling is dysregulated and demonstrates one possible approach to circumvent development of BET resistance in AML.

Mesenchymal stromal cells in myeloid malignancies: Immunotherapeutic opportunities

Myeloid malignancies are clonal disorders of the progenitor cells or hematopoietic stem cells, including acute myeloid leukemia, myelodysplastic syndromes, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid neoplastic cells affect the proliferation and differentiation of other hematopoietic lineages in the bone marrow and peripheral blood, leading to severe and life-threatening complications. Mesenchymal stromal cells (MSCs) residing in the bone marrow exert immunosuppressive functions by suppressing innate and adaptive immune systems, thus creating a supportive and tolerant microenvironment for myeloid malignancy progression. This review summarizes the significant features of MSCs in myeloid malignancies, including their role in regulating cell growth, cell death, and antineoplastic resistance, in addition to their immunosuppressive contributions. Understanding the implications of MSCs in myeloid malignancies could pave the path for potential use in immunotherapy.

Expression of Prostaglandin Genes and β-Catenin in Whole Blood as Potential Markers of Muscle Degeneration

Prostaglandin signaling pathways are closely related to inflammation, but also muscle regeneration and processes associated with frailty and sarcopenia, whereas β-catenin (CTNNB1 gene) as a part of Wnt signaling is also involved in the differentiation of muscle cells and fibrosis. The present study analyzed the association between selected prostaglandin pathway genes and clinical parameters in patients with sarcopenia and frailty syndrome. The present study was conducted on patients with sarcopenia, frailty syndrome, and control older patients (N = 25). Additionally, two healthy controls at the age of 25-30 years (N = 51) and above 50 years old (N = 42) were included. The expression of the PTRGER4, PTGES2 (COX2), PTGS2, and CTNNB1 genes in whole blood was checked by the qPCR method. The serum cytokine levels (IL-10, TNFα, IFN-y, IL-1α, IL-1β) in patients and controls were checked by the Q-Plex Human Cytokine Panel. The results showed a significant effect of age on PTGER4 gene expression (p = 0.01). A negative trend between the appendicular skeletal muscle mass parameter (ASSM) and the expression of PTGER4 has been noted (r = -0.224, p = 0.484). PTGES2 and PTGS2 expressions negatively correlated with creatine phosphokinase (r = -0.71, p = 0.009; r = -0.58, p = 0.047) and positively with the functional mobility test timed up and go scale (TUG) (r = 0.61, p = 0.04; r = 0.63, p = 0.032). In the older control group, a negative association between iron levels and the expression of PTGS2 (r = -0.47, p = 0.017) was observed. A similar tendency was noted in patients with sarcopenia (r = -0.112, p = 0.729). A negative trend between appendicular skeletal muscle mass (ASMM) and PTGER4 seems to confirm the impairment of muscle regeneration associated with sarcopenia. The expression of the studied genes revealed a trend in associations with the clinical picture of muscular dystrophy and weakening patients. Perhaps PTGS2 and PTGES2 is in opposition to the role of the PTGER4 receptor in muscle physiology. Nevertheless, further, including functional studies is needed.

TCDD alters essential transcriptional regulators of osteogenic differentiation in multipotent mesenchymal stem cells

Differentiation of multipotent mesenchymal stem cells (MSCs) into bone-forming osteoblasts requires strict coordination of transcriptional pathways. Aryl hydrocarbon receptor ligands, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), have been shown to alter osteoblast differentiation in vitro and bone formation in multiple developmental in vivo models. The goal of the present study was to establish a global transcriptomic landscape during early, intermediate, and apical stages of osteogenic differentiation in vitro in response to TCDD exposure. Human bone-derived mesenchymal stem cells (hBMSCs) were cultured in growth media (GM), osteogenic differentiation media (ODM), or ODM containing 10 nM TCDD (ODM + TCDD), thus enabling a comparison of the transcriptomic profiles of undifferentiated, differentiated, and differentiated-TCDD-exposed hBMSCs, respectively. In this test system, exposure to TCDD attenuated the differentiation of hBMSCs into osteoblasts as evidenced by reduced alkaline phosphatase activity and mineralization. At various timepoints, we observed altered expression of genes that play a role in the Wnt, fibroblast growth factor, bone morphogenetic protein/transforming growth factor beta developmental pathways, as well as pathways related to extracellular matrix organization and deposition. Reconstruction of gene regulatory networks with the interactive dynamic regulatory event miner (iDREM) analysis revealed modulation of transcription factors (TFs) including POLR3G, NR4A1, RDBP, GTF2B, POU2F2, and ZEB1, which may putatively influence osteoblast differentiation and the requisite deposition and mineralization of bone extracellular matrix. We demonstrate that the combination of RNA-Seq data in conjunction with the iDREM regulatory model captures the transcriptional dynamics underlying MSC differentiation under different conditions in vitro. Model predictions are consistent with existing knowledge and provide a new tool to identify novel pathways and TFs that may facilitate a better understanding of the osteoblast differentiation process, perturbation by exogenous agents, and potential intervention strategies targeting those specific pathways.

Clinicopathological and prognostic significance of COX-2 in glioma patients: a meta-analysis

BACKGROUND

In recent years, cyclooxygenase-2 (COX-2) has been identified as a cancer stem cell (CSC) marker in gliomas. Nevertheless, the clinical and prognostic significance of COX-2 in glioma patients remains controversial.

OBJECTIVE

To evaluate the correlation of COX-2 with the prognosis in glioma patients.

METHODS

Eligible studies on this subject were included, and pooled odd ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (95%CIs) were estimated. Publication bias was assessed through funnel plots, and heterogeneity and sensitivity were analyzed as well.

RESULTS

In the present study, 11 articles with a total of 641 patients were included. The high expression of COX-2 in glioma patients was negatively associated with overall survival (OS) (n = 11; HR = 2.26; 95%CI = 1.79-2.86), and the subgroup analysis showed no differences in OS between Asian (n = 5; HR = 2.16; 95%CI = 1.57-2.97) and non-Asian (n = 6; HR = 2.39; 95%CI = 1.69-3.38) glioma patients. The Begg funnel plots test indicated that there was no evident risk of publication bias in the meta-analysis.

CONCLUSION

The present study suggests that COX-2 could be recommended as a useful pathological and prognostic biomarker in the clinical practice.

The immunological role of mesenchymal stromal cells in patients with myelodysplastic syndrome

Myelodysplastic syndrome (MDS) is a common hematological malignant disease, characterized by malignant hematopoietic stem cell proliferation in the bone marrow (BM); clinically, it mainly manifests clinically mainly by as pathological hematopoiesis, hemocytopenia, and high-risk transformation to acute leukemia. Several studies have shown that the BM microenvironment plays a critical role in the progression of MDS. In this study, we specifically evaluated mesenchymal stromal cells (MSCs) that exert immunomodulatory effects in the BM microenvironment. This immunomodulatory effect occurs through direct cell-cell contact and the secretion of soluble cytokines or micro vesicles. Several researchers have compared MSCs derived from healthy donors to low-risk MDS-associated bone mesenchymal stem cells (BM-MSCs) and have found no significant abnormalities in the MDS-MSC phenotype; however, these cells have been observed to exhibit altered function, including a decline in osteoblastic function. This altered function may promote MDS progression. In patients with MDS, especially high-risk patients, MSCs in the BM microenvironment regulate immune cell function, such as that of T cells, B cells, natural killer cells, dendritic cells, neutrophils, myeloid-derived suppressor cells (MDSCs), macrophages, and Treg cells, thereby enabling MDS-associated malignant cells to evade immune cell surveillance. Alterations in MDS-MSC function include genomic instability, microRNA production, histone modification, DNA methylation, and abnormal signal transduction and cytokine secretion.

Regulation of hematopoietic and leukemia stem cells by regulatory T cells

Adult bone marrow (BM) hematopoietic stem cells (HSCs) are maintained in a quiescent state and sustain the continuous production of all types of blood cells. HSCs reside in a specialized microenvironment the so-called HSC niche, which equally promotes HSC self-renewal and differentiation to ensure the integrity of the HSC pool throughout life and to replenish hematopoietic cells after acute injury, infection or anemia. The processes of HSC self-renewal and differentiation are tightly controlled and are in great part regulated through cellular interactions with classical (e.g. mesenchymal stromal cells) and non-classical niche cells (e.g. immune cells). In myeloid leukemia, some of these regulatory mechanisms that evolved to maintain HSCs, to protect them from exhaustion and immune destruction and to minimize the risk of malignant transformation are hijacked/disrupted by leukemia stem cells (LSCs), the malignant counterpart of HSCs, to promote disease progression as well as resistance to therapy and immune control. CD4⁺ regulatory T cells (Tregs) are substantially enriched in the BM compared to other secondary lymphoid organs and are crucially involved in the establishment of an immune privileged niche to maintain HSC quiescence and to protect HSC integrity. In leukemia, Tregs frequencies in the BM even increase. Studies in mice and humans identified the accumulation of Tregs as a major immune-regulatory mechanism. As cure of leukemia implies the elimination of LSCs, the understanding of these immune-regulatory processes may be of particular importance for the development of future treatments of leukemia as targeting major immune escape mechanisms which revolutionized the treatment of solid tumors such as the blockade of the inhibitory checkpoint receptor programmed cell death protein 1 (PD-1) seems less efficacious in the treatment of leukemia. This review will summarize recent findings on the mechanisms by which Tregs regulate stem cells and adaptive immune cells in the BM during homeostasis and in leukemia.

Therapeutic potential of NR4A1 in cancer: Focus on metabolism

Metabolic reprogramming is a vital hallmark of cancer, and it provides the necessary energy and biological materials to support the continuous proliferation and survival of tumor cells. NR4A1 is belonging to nuclear subfamily 4 (NR4A) receptors. NR4A1 plays diverse roles in many tumors, including melanoma, colorectal cancer, breast cancer, and hepatocellular cancer, to regulate cell growth, apoptosis, metastasis. Recent reports shown that NR4A1 exhibits unique metabolic regulating effects in cancers. This receptor was first found to mediate glycolysis via key enzymes glucose transporters (GLUTs), hexokinase 2 (HK2), fructose phosphate kinase (PFK), and pyruvate kinase (PK). Then its functions extended to fatty acid synthesis by modulating CD36, fatty acid-binding proteins (FABPs), sterol regulatory element-binding protein 1 (SREBP1), glutamine by Myc, mammalian target of rapamycin (mTOR), and hypoxia-inducible factors alpha (HIF-1α), respectively. In addition, NR4A1 is involving in amino acid metabolism and tumor immunity by metabolic processes. More and more NR4A1 ligands are found to participate in tumor metabolic reprogramming, suggesting that regulating NR4A1 by novel ligands is a promising approach to alter metabolism signaling pathways in cancer therapy. Basic on this, this review highlighted the diverse metabolic roles of NR4A1 in cancers, which provides vital references for the clinical application.

The 532 nm Laser Treatment Promotes the Proliferation of Tendon-Derived Stem Cells and Upregulates Nr4a1 to Stimulate Tenogenic Differentiation

Objective: This study aimed to verify the effect of photobiomodulation therapy (PBMT) with a wavelength of 532 nm on the proliferation and differentiation of tendon-derived stem cells (TDSCs) of Sprague-Dawley (SD) rats. Background: The combination of PBMT and stem cell transplantation with TDSCs provides a new treatment strategy for tendon injury. Nevertheless, the effect of PBMT on the biological behavior of TDSCs and its internal mechanisms remain unclear. Methods: TDSCs were isolated from Achilles tendons of SD rats and identified by cell morphology and flow cytometric analysis. Energy density gradient experiment was performed to determine the ideal energy. Then, TDSCs were treated with PBMT using a wavelength of 532 nm at a fluence of 15 J/cm² in 532 nm laser group, and the TDSC in control group were not treated with 532 nm laser. Cell response after irradiation was observed to ascertain cell morphology and cell proliferation in the 532 nm laser group and the control group. The RNA expression levels of the key genes of TDSC differentiation, including scleraxis (Scx), tenomodulin (Tnmd), Mohawk homeobox (Mkx), Decorin (Dcn), peroxisome proliferator-activated receptor gamma (PPARγ), SRY-box transcription factor 9 (Sox9), and RUNX family transcription factor 2 (Runx2), were detected by reverse transcription-polymerase chain reaction. Then, gene chip microarray was used to detect the expression of differential genes after 532 nm laser intervention in TDSCs, and the target genes were screened out to verify the role in this process in vitro and in vivo. Results: When the 532 nm laser energy density was 15 J/cm², the proliferation capacity of TDSCs was improved (2.73 ± 0.24 vs. 1.81 ± 0.71, p < 0.05), and the expression of genes related to tenogenic differentiation of TDSCs was significantly increased (p < 0.01). After RNA sequencing and bioinformatics analyses, we speculated that nuclear receptor subfamily 4 group A member 1 (Nr4a1) was involved in the tenogenic differentiation process of TDSCs regulated by 532 nm laser treatment. Subsequent experiments confirmed that Nr4a1 regulated the expression of the tenogenic differentiation genes Scx and Tnmd in TDSCs. Conclusions: A 532 nm laser with 15 J/cm² regulated the process of TDSC proliferation and upregulated Nr4a1 to stimulate tenogenic differentiation.

TA-MSCs, TA-MSCs-EVs, MIF: their crosstalk in immunosuppressive tumor microenvironment

As an important component of the immunosuppressive tumor microenvironment (TME), it has been established that mesenchymal stem cells (MSCs) promote the progression of tumor cells. MSCs can directly promote the proliferation, migration, and invasion of tumor cells via cytokines and chemokines, as well as promote tumor progression by regulating the functions of anti-tumor immune and immunosuppressive cells. MSCs-derived extracellular vesicles (MSCs-EVs) contain part of the plasma membrane and signaling factors from MSCs; therefore, they display similar effects on tumors in the immunosuppressive TME. The tumor-promoting role of macrophage migration inhibitory factor (MIF) in the immunosuppressive TME has also been revealed. Interestingly, MIF exerts similar effects to those of MSCs in the immunosuppressive TME. In this review, we summarized the main effects and related mechanisms of tumor-associated MSCs (TA-MSCs), TA-MSCs-EVs, and MIF on tumors, and described their relationships. On this basis, we hypothesized that TA-MSCs-EVs, the MIF axis, and TA-MSCs form a positive feedback loop with tumor cells, influencing the occurrence and development of tumors. The functions of these three factors in the TME may undergo dynamic changes with tumor growth and continuously affect tumor development. This provides a new idea for the targeted treatment of tumors with EVs carrying MIF inhibitors.

Immunometabolism modulation, a new trick of edible and medicinal plants in cancer treatment

The edible and medicinal plants (EMPs) are becoming an abundant source for cancer prevention and treatment since the natural and healthy trend for modern human beings. Currently, there are more than one hundred species of EMPs widely used and listed by the national health commission of China, and most of them indicate immune or metabolic regulation potential in cancer treatment with numerous studies over the past two decades. In the present review, we focused on the metabolic influence in immunocytes and tumor microenvironment, including immune response, immunosuppressive factors and cancer cells, discussing the immunometabolic potential of EMPs in cancer treatment. There are more than five hundred references collected and analyzed through retrieving pharmacological studies deposited in PubMed by medical subject headings and the corresponding names derived from pharmacopoeia of China as a sole criterion. Finally, the immunometabolism modulation of EMPs was sketch out implying an immunometabolic control in cancer treatment.

Mitochondrial Effects on Seeds of Cancer Survival in Leukemia

The cancer metabolic alteration is considered a hallmark and fast becoming a road for therapeutic intervention. Mitochondria have been regarded as essential cell elements that fuel the metabolic needs of most cancer cell types. Leukemia stem cells (LSCs) are a heterogeneous, highly self-renewing, and pluripotent cell population within leukemic cells. The most important source of ATP and metabolites to fulfill the bioenergetics and biosynthetic needs of most cancer stem cells is the mitochondria. In addition, mitochondria have a core role in autophagy and cell death and are the main source of reactive oxygen species (ROS) generation. Overall, growing evidence now shows that mitochondrial activities and pathways have changed to adapt with different types of leukemia, thus mitochondrial metabolism could be targeted for blood malignancy therapy. This review focuses on the function of mitochondria in LSC of the different leukemia types.

Niche-directed therapy in acute myeloid leukemia: optimization of stem cell competition for niche occupancy

Acute myeloid leukemia (AML) is an aggressive malignancy of stem cell origin that contributes to significant morbidity and mortality. The long-term prognosis remains dismal given the high likelihood for primary refractory or relapsed disease. An essential component of relapse is resurgence from the bone marrow. To date, the murine hematopoietic stem cell (HSC) niche has been clearly defined, but the human HSC niche is less well understood. The design of niche-based targeted therapies for AML must account for which cellular subsets compete for stem cell occupancy within respective bone marrow microenvironments. In this review, we highlight the principles of stem cell niche biology and discuss translational insights into the AML microenvironment as of 2021. Optimization of competition for niche occupancy is important for the elimination of measurable residual disease (MRD). Some of these novel therapeutics are in the pharmacologic pipeline for AML and may be especially useful in the setting of MRD.

Clinical Proteomics of Biofluids in Haematological Malignancies

Since the emergence of high-throughput proteomic techniques and advances in clinical technologies, there has been a steady rise in the number of cancer-associated diagnostic, prognostic, and predictive biomarkers being identified and translated into clinical use. The characterisation of biofluids has become a core objective for many proteomic researchers in order to detect disease-associated protein biomarkers in a minimally invasive manner. The proteomes of biofluids, including serum, saliva, cerebrospinal fluid, and urine, are highly dynamic with protein abundance fluctuating depending on the physiological and/or pathophysiological context. Improvements in mass-spectrometric technologies have facilitated the in-depth characterisation of biofluid proteomes which are now considered hosts of a wide array of clinically relevant biomarkers. Promising efforts are being made in the field of biomarker diagnostics for haematologic malignancies. Several serum and urine-based biomarkers such as free light chains, β-microglobulin, and lactate dehydrogenase are quantified as part of the clinical assessment of haematological malignancies. However, novel, minimally invasive proteomic markers are required to aid diagnosis and prognosis and to monitor therapeutic response and minimal residual disease. This review focuses on biofluids as a promising source of proteomic biomarkers in haematologic malignancies and a key component of future diagnostic, prognostic, and disease-monitoring applications.

Transcriptional Profiling of Monocytes Deficient in Nuclear Orphan Receptors NR4A2 and NR4A3 Reveals Distinct Signalling Roles Related to Antigen Presentation and Viral Response

The nuclear receptor sub-family 4 group A (NR4A) family are early response genes that encode proteins that are activated in several tissues/cells in response to a variety of stressors. The NR4A family comprises NR4A1, NR4A2 and NR4A3 of which NR4A2 and NR4A3 are under researched and less understood, particularly in the context of immune cells. NR4A expression is associated with multiple diseases e.g. arthritis and atherosclerosis and the development of NR4A-targetting molecules as therapeutics is a current focus in this research field. Here, we use a combination of RNA-sequencing coupled with strategic bioinformatic analysis to investigate the down-stream effects of NR4A2 and NR4A3 in monocytes and dissect their common and distinct signalling roles. Our data reveals that NR4A2 and NR4A3 depletion has a robust and broad-reaching effect on transcription in both the unstimulated state and in the presence of LPS. Interestingly, many of the genes affected were present in both the unstimulated and stimulated states revealing a previously unappreciated role for the NR4As in unstimulated cells. Strategic clustering and bioinformatic analysis identified both distinct and common transcriptional roles for NR4A2 and NR4A3 in monocytes. NR4A2 notably was linked by both bioinformatic clustering analysis and transcription factor interactome analysis to pathways associated with antigen presentation and regulation of MHC genes. NR4A3 in contrast was more closely linked to pathways associated with viral response. Functional studies further support our data analysis pointing towards preferential/selective roles for NR4A2 in the regulation of antigen processing with common roles for NR4A2 and NR4A3 evident with respect to cell migration. Taken together this study provides novel mechanistic insights into the role of the enigmatic nuclear receptors NR4A2 and NR4A3 in monocytes.

Myeloid-Derived Suppressor Cells and Mesenchymal Stem/Stromal Cells in Myeloid Malignancies

Myeloid malignancies arise from an altered hematopoietic stem cell and mainly comprise acute myeloid leukemia, myelodysplastic syndromes, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid neoplastic leukemic cells may influence the growth and differentiation of other hematopoietic cell lineages in peripheral blood and bone marrow. Myeloid-derived suppressor cells (MDSCs) and mesenchymal stromal cells (MSCs) display immunoregulatory properties by controlling the innate and adaptive immune systems that may induce a tolerant and supportive microenvironment for neoplasm development. This review analyzes the main features of MDSCs and MSCs in myeloid malignancies. The number of MDSCs is elevated in myeloid malignancies exhibiting high immunosuppressive capacities, whereas MSCs, in addition to their immunosuppression contribution, regulate myeloid leukemia cell proliferation, apoptosis, and chemotherapy resistance. Moreover, MSCs may promote MDSC expansion, which may mutually contribute to the creation of an immuno-tolerant neoplasm microenvironment. Understanding the implication of MDSCs and MSCs in myeloid malignancies may favor their potential use in immunotherapeutic strategies.

Myeloid-Derived Suppressor Cells and Mesenchymal Stem/Stromal Cells in Myeloid Malignancies

Myeloid malignancies arise from an altered hematopoietic stem cell and mainly comprise acute myeloid leukemia, myelodysplastic syndromes, myeloproliferative malignancies, and chronic myelomonocytic leukemia. Myeloid neoplastic leukemic cells may influence the growth and differentiation of other hematopoietic cell lineages in peripheral blood and bone marrow. Myeloid-derived suppressor cells (MDSCs) and mesenchymal stromal cells (MSCs) display immunoregulatory properties by controlling the innate and adaptive immune systems that may induce a tolerant and supportive microenvironment for neoplasm development. This review analyzes the main features of MDSCs and MSCs in myeloid malignancies. The number of MDSCs is elevated in myeloid malignancies exhibiting high immunosuppressive capacities, whereas MSCs, in addition to their immunosuppression contribution, regulate myeloid leukemia cell proliferation, apoptosis, and chemotherapy resistance. Moreover, MSCs may promote MDSC expansion, which may mutually contribute to the creation of an immuno-tolerant neoplasm microenvironment. Understanding the implication of MDSCs and MSCs in myeloid malignancies may favor their potential use in immunotherapeutic strategies.

Hepatic stellate cells promote intrahepatic cholangiocarcinoma progression via NR4A2/osteopontin/Wnt signaling axis

Intrahepatic cholangiocarcinoma (ICC) is a highly fatal malignancy characterized by a vast amount of intra-tumoral fibroblasts. These fibroblasts are potentially implicated in maintaining the high aggressiveness of ICC, whereas its pro-cancer mechanisms remain scarcely reported. Here, by establishing co-culture models of ICC cells and hepatic stellate cells (HSCs), we identified that HSCs triggered the expression of nuclear receptor family 4 subgroup A member 2 (NR4A2), a transcription factor previously reported as a molecular switch between inflammation and cancer, in ICC cells. Functionally, NR4A2 promotes tumor proliferation, metastatic potentiality and represents an independent prognostic indicator for overall survival in ICC patients. Mechanistically, NR4A2 upregulates osteopontin (OPN) expression through transcriptional activation and thereby augments the activity of Wnt/β-catenin signaling. Intriguingly, in the context of co-culture, vascular endothelial growth factor (VEGF), a previously proved NR4A2 stimulus, not only enhances NR4A2 expression, but also can be blunted by the interference of the NR4A2-OPN axis. Altogether, this study suggests the NR4A2/OPN/Wnt signaling axis to be a pivotal executor of HSC-instigated cancer-promoting roles in ICC, and the NR4A2/OPN/VEGF positive feedback loop may help to reinforce the effect.

Targeting NR4A Nuclear Receptors to Control Stromal Cell Inflammation, Metabolism, Angiogenesis, and Tumorigenesis

The NR4A1–NR4A3 (Nur77, Nurr1, and Nor-1) subfamily of nuclear receptors is a group of immediate early genes induced by a pleiotropy of stimuli including peptide hormones, growth factors, cytokines, inflammatory, and physiological stimuli, and cellular stress. NR4A receptors function as potent sensors of changes in the cellular microenvironment to control physiological and pathological processes through genomic and non-genomic actions. NR4A receptors control metabolism and cardiovascular and neurological functions and mediate immune cell homeostasis in inflammation and cancer. This receptor subfamily is increasingly recognized as an important molecular connection between chronic inflammation, altered immune cell responses, and cancer development. In this review, we examine how transcriptome analysis identified NR4A1/NR4A2 receptors as transcriptional regulators in mesenchymal stromal cell (MSC) migration, cell cycle progression, and cytokine production to control local immune responses. In chronic inflammatory conditions, such as rheumatoid arthritis, NR4A receptors have been shown to modify the activity of MSC and fibroblast-like stromal cells to regulate synovial tissue hyperplasia, pathological angiogenesis, and cartilage turnover in vivo. Additionally, as NR4A1 has been observed as a major transcriptional regulator in tumor–stromal communication controlling tumorigenesis, we discuss how advances in the pharmacological control of these receptors lead to important new mechanistic insights into understanding the role of the tumor microenvironment in health and disease.

Wnt Signaling in the Tumor Microenvironment

Dysregulated Wnt signaling plays a central role in initiation, progression, and metastasis in many types of human cancers. Cancer development and resistance to conventional cancer therapies are highly associated with the tumor microenvironment (TME), which is composed of numerous stable non-cancer cells, including immune cells, extracellular matrix (ECM), fibroblasts, endothelial cells (ECs), and stromal cells. Recently, increasing evidence suggests that the relationship between Wnt signaling and the TME promotes the proliferation and maintenance of tumor cells, including leukemia. Here, we review the Wnt pathway, the role of Wnt signaling in different components of the TME, and therapeutic strategies for targeting Wnt signaling.

Age-related transcriptome changes in melanoma patients with tumor-positive sentinel lymph nodes

Age is an important factor for determining the outcome of melanoma patients. Sentinel lymph node (SLN) status is also a strong predictor of survival for melanoma. Paradoxically, older melanoma patients have a lower incidence of SLN metastasis but a higher mortality rate when compared with their younger counterparts. The mechanisms that underlie this phenomenon remain unknown. This study uses three independent datasets of RNA samples from patients with melanoma metastatic to the SLN to identify age-related transcriptome changes in SLNs and their association with outcome. Microarray was applied to the first dataset of 97 melanoma patients. NanoString was performed in the second dataset to identify the specific immune genes and pathways that are associated with recurrence in younger versus older patients. qRT-PCR analysis was used in the third dataset of 36 samples to validate the differentially expressed genes (DEGs) from microarray and NanoString. These analyses show that FOS, NR4A, and ITGB1 genes were significantly higher in older melanoma patients with positive SLNs. IRAK3- and Wnt10b-related genes are the major pathways associated with recurrent melanoma in younger and older patients with tumor-positive SLNs, respectively. This study aims to elucidate age-related differences in SLNs in the presence of nodal metastasis.

Network pharmacology-based strategy for predicting therapy targets of Tripterygium wilfordii on acute myeloid leukemia

This is a study on the potential therapeutic targets and pharmacological mechanism of Tripterygium wilfordii (TW) in acute myeloid leukemia (AML) based on network pharmacology.Active components of TW were obtained by network pharmacology through oral bioavailability, drug-likeness filtration. Comparative analysis was used to investigate the overlapping genes between active ingredient's targets and AML treatment-related targets. Using STRING database to analyze interactions among overlapping genes. Both KEGG pathway analysis and Gene Ontology enrichment analysis were conducted in DAVID. These genes were analyzed for survival in OncoLnc database.We screened 53 active ingredients; the results of comparative analysis showed that 8 active ingredients had an effect on AML treatment. On the basis of the active ingredients and overlapping genes, we constructed the Drug-Compounds-Genes-Disease Network. Survival analysis of overlapping genes indicated that some targets possessed a significant influence on patients' survival and prognosis. The enrichment analysis showed that the main pathways of targets were Toll-like receptor signaling pathway, NF-kappa B signaling pathway, and HIF-1 signaling pathway.This study, using a network pharmacologic approach, provides another strategy that can help us to understand the mechanisms by which TW treats AML comprehensively.

Bone Marrow Mesenchymal Stem Cells Support Acute Myeloid Leukemia Bioenergetics and Enhance Antioxidant Defense and Escape from Chemotherapy

Like normal hematopoietic stem cells, leukemic stem cells depend on their bone marrow (BM) microenvironment for survival, but the underlying mechanisms remain largely unknown. We have studied the contribution of nestin+ BM mesenchymal stem cells (BMSCs) to MLL-AF9-driven acute myeloid leukemia (AML) development and chemoresistance in vivo. Unlike bulk stroma, nestin+ BMSC numbers are not reduced in AML, but their function changes to support AML cells, at the expense of non-mutated hematopoietic stem cells (HSCs). Nestin+ cell depletion delays leukemogenesis in primary AML mice and selectively decreases AML, but not normal, cells in chimeric mice. Nestin+ BMSCs support survival and chemotherapy relapse of AML through increased oxidative phosphorylation, tricarboxylic acid (TCA) cycle activity, and glutathione (GSH)-mediated antioxidant defense. Therefore, AML cells co-opt energy sources and antioxidant defense mechanisms from BMSCs to survive chemotherapy.

Role of Nurr1 in Carcinogenesis and Tumor Immunology: A State of the Art Review

Simple Summary

Nuclear receptor related-1 protein (Nurr1) emerges as a therapeutic target in multiple malignancies and immunotherapies. Previous studies have highlighted its association with clinicopathological parameters, tumorigenesis and therapeutic resistance in cancers. In addition, recent studies unraveled its contribution to the suppression of antitumor immunity, suggesting that inhibition of Nurr1 is a potential method to repress cancer aggressiveness and disrupt tumor immune tolerance. In line with this evidence, the present review provides the roles of Nurr1 in tumor progression and the associated underlying molecular mechanisms. Moreover, the significance of Nurr1 in promoting immune tolerance and potential strategies for Nurr1 inhibition are highlighted.

Abstract

Nuclear receptor related-1 protein (Nurr1), coded by an early response gene, is involved in multiple cellular and physiological functions, including proliferation, survival, and self-renewal. Dysregulation of Nurr1 has been frequently observed in many cancers and is attributed to multiple transcriptional and post-transcriptional mechanisms. Besides, Nurr1 exhibits extensive crosstalk with many oncogenic and tumor suppressor molecules, which contribute to its potential pro-malignant behaviors. Furthermore, Nurr1 is a key player in attenuating antitumor immune responses. It not only potentiates immunosuppressive functions of regulatory T cells but also dampens the activity of cytotoxic T cells. The selective accessibility of chromatin by Nurr1 in T cells is closely associated with cell exhaustion and poor efficacy of cancer immunotherapy. In this review, we summarize the reported findings of Nurr1 in different malignancies, the mechanisms that regulate Nurr1 expression, and the downstream signaling pathways that Nurr1 employs to promote a wide range of malignant phenotypes. We also give an overview of the association between Nurr1 and antitumor immunity and discuss the inhibition of Nurr1 as a potential immunotherapeutic strategy.

Wnt Signaling in Leukemia and Its Bone Marrow Microenvironment

Leukemia is an aggressive hematologic neoplastic disease. Therapy-resistant leukemic stem cells (LSCs) may contribute to the relapse of the disease. LSCs are thought to be protected in the leukemia microenvironment, mainly consisting of mesenchymal stem/stromal cells (MSC), endothelial cells, and osteoblasts. Canonical and noncanonical Wnt pathways play a critical role in the maintenance of normal hematopoietic stem cells (HSC) and LSCs. In this review, we summarize recent findings on the role of Wnt signaling in leukemia and its microenvironment and provide information on the currently available strategies for targeting Wnt signaling.

Mesenchymal Stem Cells in Aplastic Anemia and Myelodysplastic Syndromes: The "Seed and Soil" Crosstalk

There is growing interest in the contribution of the marrow niche to the pathogenesis of bone marrow failure syndromes, i.e., aplastic anemia (AA) and myelodysplastic syndromes (MDSs). In particular, mesenchymal stem cells (MSCs) are multipotent cells that contribute to the organization and function of the hematopoietic niche through their repopulating and supporting abilities, as well as immunomodulatory properties. The latter are of great interest in MDSs and, particularly, AA, where an immune attack against hematopoietic stem cells is the key pathogenic player. We, therefore, conducted Medline research, including all available evidence from the last 10 years concerning the role of MSCs in these two diseases. The data presented show that MSCs display morphologic, functional, and genetic alterations in AA and MDSs and contribute to immune imbalance, ineffective hematopoiesis, and leukemic evolution. Importantly, adoptive MSC infusion from healthy donors can be exploited to heal the "sick" niche, with even better outcomes if cotransplanted with allogeneic hematopoietic stem cells. Finally, future studies on MSCs and the whole microenvironment will further elucidate AA and MDS pathogenesis and possibly improve treatment.

Inhibition of NF-κB Signaling Alters Acute Myelogenous Leukemia Cell Transcriptomics

Acute myelogenous leukemia (AML) is an aggressive hematological malignancy. The pathophysiology of the disease depends on cytogenetic abnormalities, gene mutations, aberrant gene expressions, and altered epigenetic regulation. Although new pharmacological agents have emerged during the last years, the prognosis is still dismal and new therapeutic strategies are needed. The transcription factor nuclear factor-κB (NF-κB) is regarded a possible therapeutic target. In this study, we investigated the alterations in the global gene expression profile (GEP) in primary AML cells derived from 16 consecutive patients after exposure to the NF-κB inhibitor BMS-345541. We identified a profound and highly discriminative transcriptomic profile associated with NF-κB inhibition. Bioinformatical analyses identified cytokine/interleukin signaling, metabolic regulation, and nucleic acid binding/transcription among the major biological functions influenced by NF-κB inhibition. Furthermore, several key genes involved in leukemogenesis, among them RUNX1 and CEBPA, in addition to NFKB1 itself, were influenced by NF-κB inhibition. Finally, we identified a significant impact of NF-κB inhibition on the expression of genes included in a leukemic stem cell (LSC) signature, indicating possible targeting of LSCs. We conclude that NF-κB inhibition significantly altered the expression of genes central to the leukemic process.

NR4A1 promotes TNF‑α‑induced chondrocyte death and migration injury via activating the AMPK/Drp1/mitochondrial fission pathway

Nuclear receptor subfamily 4 group A member 1 (NR4A1)-induced chondrocyte death plays a critical role in the development of osteoarthritis through poorly defined mechanisms. The present study aimed to investigate the role of NR4A1 in regulating chondrocyte death in response to tumor necrosis factor-α (TNF-α) and cycloheximide (CHX) treatment, with a focus on mitochondrial fission and the AMP-activated protein kinase (AMPK) signaling pathway. The results demonstrated that NR4A1 was significantly upregulated in TNF-α and CHX exposed chondrocytes. Increased NR4A1 triggered mitochondrial fission via the AMPK/dynamin-related protein 1 (Drp1) pathway, resulting in mitochondrial dysfunction, and mitochondrial permeability transition pore (mPTP) opening-related cell death. Furthermore, excessive mitochondrial fission impaired chondrocyte migration through imbalance of F-actin homeo-stasis. Inhibiting NR4A1 attenuated TNF-α and CHX-induced mitochondrial fission and, thus, reduced mitochondrial dysfunction in chondrocytes, mPTP opening-related cell death and migration injury. Altogether, the present data confirmed that mitochondrial fission was involved in NR4A1-mediated chondrocyte injury via regulation of mitochondrial dysfunction, mPTP opening-induced cell death and F-actin-related migratory inhibition.

Wnt/β-catenin signaling pathway safeguards epigenetic stability and homeostasis of mouse embryonic stem cells

Mouse embryonic stem cells (mESCs) are pluripotent and can differentiate into cells belonging to the three germ layers of the embryo. However, mESC pluripotency and genome stability can be compromised in prolonged in vitro culture conditions. Several factors control mESC pluripotency, including Wnt/β-catenin signaling pathway, which is essential for mESC differentiation and proliferation. Here we show that the activity of the Wnt/β-catenin signaling pathway safeguards normal DNA methylation of mESCs. The activity of the pathway is progressively silenced during passages in culture and this results into a loss of the DNA methylation at many imprinting control regions (ICRs), loss of recruitment of chromatin repressors, and activation of retrotransposons, resulting into impaired mESC differentiation. Accordingly, sustained Wnt/β-catenin signaling maintains normal ICR methylation and mESC homeostasis and is a key regulator of genome stability.