Targeting the CXCR4/CXCL12 axis with the peptide antagonist E5 to inhibit breast tumor progression

CXCL12-CXCR4/CXCR7 Axis in Cancer: from Mechanisms to Clinical Applications

Cancer is a multi-step disease caused by the accumulation of genetic mutations and/or epigenetic changes, and is the biggest challenge around the world. Cytokines, including chemokines, exhibit expression changes and disorders in all human cancers. These cytokine abnormalities can disrupt homeostasis and immune function, and make outstanding contributions to various stages of cancer development such as invasion, metastasis, and angiogenesis. Chemokines are a superfamily of small molecule chemoattractive cytokines that mediate a variety of cellular functions. Importantly, the interactions of chemokine members CXCL12 and its receptors CXCR4 and CXCR7 have a broad impact on tumor cell proliferation, survival, angiogenesis, metastasis, and tumor microenvironment, and thus participate in the onset and development of many cancers including leukemia, breast cancer, lung cancer, prostate cancer and multiple myeloma. Therefore, this review aims to summarize the latest research progress and future challenges regarding the role of CXCL12-CXCR4/CXCR7 signaling axis in cancer, and highlights the potential of CXCL12-CXCR4/CXCR7 as a biomarker or therapeutic target for cancer, providing essential strategies for the development of novel targeted cancer therapies.

Current research status of anti-cancer peptides: Mechanism of action, production, and clinical applications

The escalating rate of cancer cases, together with treatment deficiencies and long-term side effects of currently used cancer drugs, has made this disease a global burden of the 21st century. The number of breast and lung cancer patients has sharply increased worldwide in the last few years. Presently, surgical treatment, radiotherapy, chemotherapy, and immunotherapy strategies are used to cure cancer, which cause severe side effects, toxicities, and drug resistance. In recent years, anti-cancer peptides have become an eminent therapeutic strategy for cancer treatment due to their high specificity and fewer side effects and toxicity. This review presents an updated overview of different anti-cancer peptides, their mechanisms of action and current production strategies employed for their manufacture. In addition, approved and under clinical trials anti-cancer peptides and their applications have been discussed. This review provides updated information on therapeutic anti-cancer peptides that hold great promise for cancer treatment in the near future.

CXC Chemokine Receptor Type 4 Antagonistic Gold Nanorods Induce Specific Immune Responses and Long-Term Immune Memory to Combat Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is highly challenging in its treatment because of the lack of the targeted markers. TNBC patients are not able to acquire benefits from endocrine therapy and targeted therapy except for chemotherapy. CXCR4 is highly expressed on TNBC cells that mediated the tumor cell metastasis as well as proliferation by the response of its ligand CXCL12, therefore holding promising potential of a candidate target for the treatment. In this work, a novel conjugate of CXCR4 antagonist peptide E5 and gold nanorods was fabricated (AuNRs-E5), which was applied to murine breast cancer tumor cells and an animal model, aiming to induce endoplasmic reticulum stress by endoplasmic reticulum-targeted photothermal immunological effects. Results showed that AuNRs-E5 could induce much more generation of damage-related molecular patterns in 4T1 cells under laser irradiation than AuNRs, which significantly promoted the maturation of dendritic cells and stimulated systematic anti-tumor immune responses by enhancing the infiltration of CD8⁺T cells into the tumor and tumor-draining lymph node, downregulating the regulatory T lymphocytes, and upregulating M1 macrophages in tumors, reversing the microenvironment from "cold" tumors to "hot" tumors. The administration of AuNRs-E5 with laser irradiation not only inhibited the tumor growth significantly but also exerted specific long immune responses to the triple-negative breast cancer tumor cells, which led to the prolonged survival of the mice and the specific immunological memory.

Peptide-assembled nanoparticles targeting tumor cells and tumor microenvironment for cancer therapy

Tumor cells and corrupt stromal cells in the tumor microenvironment usually overexpress cancer-specific markers that are absent or barely detectable in normal cells, providing available targets for inhibiting the occurrence and development of cancers. It is noticeable that therapeutic peptides are emerging in cancer therapies and playing more and more important roles. Moreover, the peptides can be self-assembled and/or incorporated with polymeric molecules to form nanoparticles via non-covalent bond, which have presented appealing as well as enhanced capacities of recognizing targeted cells, responding to microenvironments, mediating internalization, and achieving therapeutic effects. In this review, we will introduce the peptide-based nanoparticles and their application advances in targeting tumor cells and stromal cells, including suppressive immune cells, fibrosis-related cells, and angiogenic vascular cells, for cancer therapy.

Therapeutic Perspectives of HIV-Associated Chemokine Receptor (CCR5 and CXCR4) Antagonists in Carcinomas

The interaction between malignant cells and the tumor microenvironment is critical for tumor progression, and the chemokine ligand/receptor axes play a crucial role in this process. The CXCR4/CXCL12 and CCR5/CCL5 axes, both related to HIV, have been associated with the early (epithelial-mesenchymal transition and invasion) and late events (migration and metastasis) of cancer progression. In addition, these axes can also modulate the immune response against tumors. Thus, antagonists against the receptors of these axes have been proposed in cancer therapy. Although preclinical studies have shown promising results, clinical trials are needed to include these drugs in the oncological treatment protocols. New alternatives for these antagonists, such as dual CXCR4/CCR5 antagonists or combined therapy in association with immunotherapy, need to be studied in cancer therapy.

The FUS/circEZH2/KLF5/ feedback loop contributes to CXCR4-induced liver metastasis of breast cancer by enhancing epithelial-mesenchymal transition

Background

Metastasis of breast cancer have caused the majority of cancer-related death worldwide. The circRNAs are associated with tumorigenesis and metastasis in breast cancer according to recent research. However, the biological mechanism of circRNAs in liver metastatic breast cancer remains ambiguous yet.

Methods

Microarray analysis of three pairs of primary BC tissues and matched hepatic metastatic specimens identified circEZH2. We used RT-qPCR and FISH assays to confirm circEZH2 existence, characteristics, and expression. Both in vivo and in vitro, circEZH2 played an oncogenic role which promoted metastasis as well. A range of bioinformatic analysis, Western blot, RNA pull-down, RIP, ChIP, and animal experiments were used to define the feedback loop involving FUS, circEZH2, miR-217-5p, KLF5, FUS, CXCR4 as well as epithelial and mesenchymal transition.

Results

In our research, circEZH2 was proved to be upregulated in liver metastases in BC and predicted the worse prognosis in breast cancer patients. Overexpression of circEZH2 notably accentuated the vitality and invasion of BC cells, whereas knockdown of circEZH2 elicited the literally opposite effects. Besides, overexpressed circEZH2 promoted tumorigenesis and liver metastasis in vivo. Moreover, circEZH2 could adsorb miR-217-5p to upregulate KLF5 thus leading to activate FUS transcription which would facilitate the back-splicing program of circEZH2. Meanwhile, KLF5 could upregulated CXCR4 transcriptionally to accelerate epithelial and mesenchymal transition of breast cancer.

Conclusions

Consequently, a novel feedback loop FUS/circEZH2/KLF5/CXCR4 was established while circEZH2 could be novel biomarker and potential target for BC patients’ therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01653-2.

Growth arrest‐specific protein 2 ( GAS2 ) interacts with CXCR4 to promote T‐cell leukemogenesis partially via c‐MYC

Although growth arrest‐specific protein 2 (GAS2) promotes the growth of T‐cell acute lymphoblastic leukemia (T‐ALL) cells in culture, the effect of GAS2 on T‐cell leukemogenesis has not been studied, and the mechanism remains unclear. In the present study, xenograft studies showed that GAS2 silencing impaired T‐cell leukemogenesis and decreased leukemic cell infiltration. Mechanistically, GAS2 regulated the protein expression of C‐X‐C chemokine receptor type 4 (CXCR4) rather than its transcript expression. Immunoprecipitation revealed that GAS2 interacted with CXCR4, and confocal analysis showed that GAS2 was partially co‐expressed with CXCR4, which provided a strong molecular basis for GAS2 to regulate CXCR4 expression. Importantly, CXCR4 overexpression alleviated the inhibitory effect of GAS2 silencing on the growth and migration of T‐ALL cells. Moreover, GAS2 or CXCR4 silencing inhibited the expression of NOTCH1 and c‐MYC. Forced expression of c‐MYC rescued the growth suppression induced by GAS2 or CXCR4 silencing. Meanwhile, GAS2 deficiency, specifically in blood cells, had a mild effect on normal hematopoiesis, including T‐cell development, and GAS2 silencing did not affect the growth of normal human CD3⁺ or CD34⁺ cells. Overall, our data indicate that GAS2 promotes T‐cell leukemogenesis through its interaction with CXCR4 to activate NOTCH1/c‐MYC, whereas impaired GAS2 expression has a mild effect on normal hematopoiesis. Therefore, our study suggests that targeting the GAS2/CXCR4 axis is a potential therapeutic strategy for T‐ALL.

Downregulation of MMP-9 Enhances the Anti-Migratory Effect of Cyclophosphamide in MDA-MB-231 and MCF-7 Breast Cancer Cell Lines

Metastasis is one of the most urgent issues in breast cancer patients. One of the factors necessary in the migration process is the remodeling of the extracellular matrix (ECM). Metalloproteinases (MMPs) can break down the elements of the ECM, which facilitates cell movement. Many highly aggressive tumors are characterized by high levels of MMPs. In the case of breast cancer, the association between MMP-9 and the migration potential and invasiveness of cells has been demonstrated. In addition, reports indicating increased migration of breast cancer cells after the administration of the commonly used cytostatic cyclophosphamide (CP) are particularly disturbing. Hence, our research aimed to assess the effect of CP treatment on MDA-MB-231 and MCF-7 cells and how this response is influenced by the downregulation of the MMP-9 level. The obtained results suggest that CP causes a decrease in the survival of breast cancer cells of various invasiveness, and the downregulation of MMP-9 enhances this effect, mainly by inducing apoptosis. Moreover, in the group of MMP-9 siRNA-transfected CP-treated cells, a more severe reduction in invasion and migration of cells of both lines was observed, as indicated by the migration and invasion transwell assays and Wound healing assay. Hence, we suggest that CP alone may not result in satisfactory therapeutic effects. On the other hand, the use of combination therapy targeting MMP-9, together with the CP, could improve the effectiveness of the treatment. Additionally, we confirmed a relationship between the levels of MMP-9 and cytokeratin 19 (CK19).

A Selective Neutraligand for CXCL12/SDF-1α With Beneficial Regulatory Functions in MRL/Lpr Lupus Prone Mice

Dysregulation of CXCL12/SDF-1-CXCR4/CD184 signaling is associated with inflammatory diseases and notably with systemic lupus erythematosus. Issued from the lead molecule chalcone-4, the first neutraligand of the CXCL12 chemokine, LIT-927 was recently described as a potent analogue with improved solubility and stability. We aimed to investigate the capacity of LIT-927 to correct immune alterations in lupus-prone MRL/lpr mice and to explore the mechanism of action implemented by this small molecule in this model. We found that in contrast to AMD3100, an antagonist of CXCR4 and agonist of CXCR7, LIT-927 reduces the excessive number of several B/T lymphocyte subsets occurring in the blood of sick MRL/lpr mice (including CD3⁺/CD4^-/CD8^-/B220⁺ double negative T cells). In vitro, LIT-927 downregulated the overexpression of several activation markers on splenic MRL/lpr lymphocytes. It exerted effects on the CXCR4 pathway in MRL/lpr CD4⁺ T spleen cells. The results underline the importance of the CXCL12/CXCR4 axis in lupus pathophysiology. They indicate that neutralizing CXCL12 by the neutraligand LIT-927 can attenuate hyperactive lymphocytes in lupus. This mode of intervention might represent a novel strategy to control a common pathophysiological mechanism occurring in inflammatory diseases.

At the Bench: Pre-clinical evidence for multiple functions of CXCR4 in cancer

Signaling through chemokine receptor, C-X-C chemokine receptor type 4 (CXCR4) regulates essential processes in normal physiology, including embryogenesis, tissue repair, angiogenesis, and trafficking of immune cells. Tumors co-opt many of these fundamental processes to directly stimulate proliferation, invasion, and metastasis of cancer cells. CXCR4 signaling contributes to critical functions of stromal cells in cancer, including angiogenesis and multiple cell types in the tumor immune environment. Studies in animal models of several different types of cancers consistently demonstrate essential functions of CXCR4 in tumor initiation, local invasion, and metastasis to lymph nodes and distant organs. Data from animal models support clinical observations showing that integrated effects of CXCR4 on cancer and stromal cells correlate with metastasis and overall poor prognosis in >20 different human malignancies. Small molecules, Abs, and peptidic agents have shown anticancer efficacy in animal models, sparking ongoing efforts at clinical translation for cancer therapy. Investigators also are developing companion CXCR4-targeted imaging agents with potential to stratify patients for CXCR4-targeted therapy and monitor treatment efficacy. Here, pre-clinical studies demonstrating functions of CXCR4 in cancer are reviewed.

Anti-CXCR4 Single-Chain Variable Fragment Antibodies Have Anti-Tumor Activity

Monoclonal antibodies (mAbs) are large and have limitations as cancer therapeutics. Human single-chain variable fragment (scFv) is a small antibody as a good alternative. It can easily enter cancer tissues, has no immunogenicity and can be produced in bacteria to decrease the cost. The chemokine receptor CXCR4 is overexpressed in different cancer cells. It plays an important role in tumor growth and metastasis. Its overexpression is associated with poor prognosis in cancer patients and is regarded as an attractive target for cancer treatment. In this study, a peptide on the CXCR4 extracellular loop 2 (ECL2) was used as an antigen for screening a human scFv antibody library by yeast two-hybrid method. Three anti-CXCR4 scFv antibodies were isolated. They could bind to CXCR4 protein and three cancer cell lines (DU145, PC3, and MDA-MB-231) and not to 293T and 3T3 cells as negative controls. These three scFvs could decrease the proliferation, migration, and invasion of these cancer cells and promote their apoptosis. The two scFvs were further examined in a mouse xenograft model, and they inhibited the tumor growth. Tumor immunohistochemistry also demonstrated that the two scFvs decreased cancer cell proliferation and tumor angiogenesis and increased their apoptosis. These results show that these anti-CXCR4 scFvs can decrease cancer cell proliferation and inhibit tumor growth in mice, and may provide therapy for various cancers.

Enhanced lymphatic delivery of nanomicelles encapsulating CXCR4-recognizing peptide and doxorubicin for the treatment of breast cancer

Lymph node metastases in cancer patients are associated with high aggressiveness, poor prognosis, and short survival time. The chemokine receptor 4 (CXCR4)/stroma derived factor 1α (CXCL12) biological axis plays a critical role in the spread of cancer cells. Designing effective delivery systems that can successfully deliver CXCR4 antagonists to lymph nodes, which are rich in CXCR4-overexpressing cancer cells, for controlling cancer metastasis remain challenging. In this study, we demonstrated that such a challenge may be alleviated by developing nanometer-sized polyethylene glycol-phosphatidylethanolamine (PEG-PE) micelles for the co-delivery of the CXCR4 antagonistic peptide E5 and doxorubicin (M-E5-Dox). This nanomicelle platform enables the preferential accumulation of cargos into lymph nodes and thus can better inhibit cancer metastasis and enhance antitumor efficacy than either free drugs or single drug-loaded micelles in breast cancer-bearing mouse models. Hence, M-E5-Dox is expected to be a potential therapeutic agent that would improve the clinical benefits of breast cancer therapy and treatment of various CXCR4-overexpressing malignancies.

Chemotherapy resistance and stromal targets in breast cancer treatment: a review

Therapy resistance is a known problem in breast cancer and is associated with a variety of mechanisms. The role of the tumor microenvironment in cancer development and resistance mechanisms is becoming increasingly understood. Tumor–stroma is the main component of the tumor microenvironment. Stromal cells like cancer-associated fibroblasts (CAFs) are believed to contribute to chemotherapy resistance via the production of several secreted factors like cytokines and chemokines. CAFs are found to influence disease progression; patients with primary tumors with a high amount of tumor–stroma have a significantly worse outcome. Therefore the role of CAFs resistance mechanisms makes them a promising target in anti-cancer therapy. An overview of recent advances in strategies to target breast cancer stroma is given and the current literature regarding these stromal targets is discussed. CAF-specific proteins as well as secreted molecules involved in tumor–stroma interactions provide possibilities for stroma-specific therapy. The development of stroma-specific therapy is still in its infancy and the available literature is limited. Within the scope of personalized treatment, biomarkers based on the tumor–stroma have future potential for the improvement of treatment via image-guided surgery (IGS) and PET scanning.

Nanomedicine and chemotherapeutics drug delivery: challenges and opportunities

Cancer is considered as one of the biggest threats to humans worldwide. Researchers suggest that tumour is not just a single mass, it comprises cancerous cells surrounded by noncancerous cells such as immune cells, adipocytes and cancer stem cells (CSCs) in the extracellular matrix (ECM) containing distinct components such as proteins, glycoproteins and enzymes; thus tumour microenvironment (TME) is partially complex. Multiple interactions happen in the dynamic microenvironment (ME) lead to an acidic, hypoxic and stiff ME that is considered as one of the major contributors to cancer progression and metastasis. Furthermore, TME involves in drug resistance mechanisms and affects enhanced permeability and retention (EPR) in tumours. In such a scenario, the first step to accomplish satisfying results is the identification and recognition of this ME. Then designing proper drug delivery systems can perform selectively towards cancerous cells. In this way, several targeting and stimuli/enzyme responsive drug delivery systems have been designed. More importantly, it is necessary to design a drug delivery system that can penetrate deeper into the tumours, efficiently and selectively. Various drug delivery systems such as exosomes and size-switchable nanocarriers (NCs) could decrease side effects and increase tumour treatment results by selective accumulation in tumours. In this review, TME features, current drug delivery approaches, challenges and promising strategies towards cancer treatment are discussed.

Peptide-enabled receptor-binding-quantum dots for enhanced detection and migration inhibition of cancer cells

We report the efforts to construct active targeting quantum dots using receptor-binding peptide for enhanced detection and migration inhibition of cancer cells. Peptide E5 has specific binding with chemokine receptor 4 (CXCR4), which is a transmembrane G-coupled receptor involved in the metastasis of various types of cancers. E5 was introduced to the surface of CdSe/ZnS quantum dots via biotin-streptavidin interactions. The constructed CXCR4-targeting quantum dots (E5@QDs) was observed to display improved detection sensitivity and significantly enhanced binding affinity for CXCR4 over-expressed cancer cells, and the ability to inhibit cancer cells migration induced by CXCL12.

A Review on Targeting Nanoparticles for Breast Cancer

Chemotherapeutic agents have been used extensively in breast cancer remedy. However, most anticancer drugs cannot differentiate between cancer cells and normal cells, leading to toxic side effects. Also, the resulted drug resistance during chemotherapy reduces treatment efficacy. The development of targeted drug delivery offers great promise in breast cancer treatment both in clinical applications and in pharmaceutical research. Conjugation of nanocarriers with targeting ligands is an effective therapeutic strategy to treat cancer diseases. In this review, we focus on active targeting methods for breast cancer cells through the use of chemical ligands such as antibodies, peptides, aptamers, vitamins, hormones, and carbohydrates. Also, this review covers all information related to these targeting ligands, such as their subtypes, advantages, disadvantages, chemical modification methods with nanoparticles and recent published studies (from 2015 to present). We have discussed 28 different targeting methods utilized for targeted drug delivery to breast cancer cells with different nanocarriers delivering anticancer drugs to the tumors. These different targeting methods give researchers in the field of drug delivery all the information and techniques they need to develop modern drug delivery systems.

A Novel CXCR4 Targeting Protein SDF-1/54 as an HIV-1 Entry Inhibitor

CXC chemokine receptor 4 (CXCR4) is a co-receptor for HIV-1 entry into target cells. Its natural ligand, the chemokine SDF-1, inhibits viral entry mediated by this receptor. However, the broad expression pattern of CXCR4 and its critical roles in various physiological and pathological processes indicate that the direct application of SDF-1 as an entry inhibitor might have severe consequences. Previously, we constructed an effective SDF-1 mutant, SDF-1/54, by deleting the α-helix of the C-terminal functional region of SDF-1. Of note, SDF-1/54 shows remarkable decreased chemotoxic ability, but maintains a similar binding affinity to CXCR4, suggesting SDF-1/54 might better serve as a CXCR4 inhibitor. Here, we found that SDF-1/54 exhibited potent antiviral activity against various X4 HIV-1 strains, including the infectious clone HIV-1 NL4-3, laboratory-adapted strain HIV-1 IIIB, clinical isolates and even drug-resistant strains. By using time-of-addition assay, non-infectious and infectious cell–cell fusion assay and CXCR4 internalization assay, we demonstrated SDF-1/54 is an HIV-1 entry inhibitor. A combination of SDF-1/54 with several antiretroviral drugs exhibited potent synergistic anti-HIV-1 activity. Moreover, SDF-1/54 was stable and its anti-HIV-1 activity was not significantly affected by the presence of seminal fluid, vaginal fluid simulant and human serum albumin. SDF-1/54 showed limited in vitro cytotoxicity to lymphocytes and vaginal epithelial cells. Based on these findings, SDF-1/54 could have a therapeutic potential as an HIV-1 entry inhibitor.

Validation of [125I]CPCR4.3 as an investigative tool for the sensitive and specific detection of hCXCR4 and mCXCR4 expression in vitro and in vivo

BACKGROUND

The development and clinical translation of [68Ga] Pentixafor has substantially promoted the relevance of non-invasive PET imaging of CXCR4 expression in a broad spectrum of diseases, including cancer and inflammation. Its pronounced selectivity for the human receptor (hCXCR4), however, precludes the use of [68Ga] Pentixafor for imaging receptor expression and dynamics in CXCR4-related diseases in endogenous mouse models. To overcome this restriction, [125I]CPCR4.3, a structurally related pentapeptide ligand, has been evaluated as a preclinical tool for efficient in vitro and in vivo targeting of hCXCR4 and mCXCR4.

RESULTS

Compared to the reference [68Ga] Pentixafor, [125I]CPCR4.3 showed 2.4- to 11-fold increased specific binding to human cancer cell lines with different hCXCR4 expression levels (Jurkat, Daudi, HT-29, SH-5YSY, MCF-7, LNCaP) as well as strong and highly specific binding to mCXCR4 expressing cells (mCXCR4-transfected CHO cells, Eμ-myc 1080, 4 T1), which was not detectable for [68Ga]Pentixafor. This is the consequence of the equally high affinity of iodo-CPCR4 to hCXCR4 and mCXCR4 (IC50 = 5.4 ± 1.5 and 4.9 ± 1.7 nM, respectively) as opposed to [natGa] Pentixafor (hCXCR4: 42.4 ± 11.6 nM, mCXCR4: > 1000 nM). Additionally, [125I]CPCR4.3 showed enhanced tracer internalization (factor of 1.5-2 compared to the reference). In vivo biodistribution studies in immunocompetent Black Six and immunocompromised CD-1 nude mice showed predominant hepatobiliary excretion of [125I]CPCR4.3 (logP = 0.51), leading to high activity levels in liver and intestines. However, [125I]CPCR4.3 also showed high and specific accumulation in organs with endogenous mCXCR4 expression (spleen, lung, adrenals), even at low receptor expression levels.

CONCLUSIONS

Due to its excellent hCXCR4 and mCXCR4 targeting efficiency, both in vitro and in vivo, [125I]CPCR4.3 represents a sensitive and reliable tool for the species-independent quantification of CXCR4 expression. Its suboptimal clearance properties will certainly restrict its use for in vivo imaging applications using 123I (for SPECT) or 124I (for PET), but due to its high and specific accumulation in mCXCR4 expressing tissues, [125I]CPCR4.3 holds promise as a powerful preclinical tool for the investigation and quantification of CXCR4 involvement and kinetics in various murine disease models via, e.g., biodistribution and autoradiography studies.

Relationship between CXC chemokine receptor 4 expression and prognostic significance in acute myeloid leukemia

CXC chemokine receptor 4 (CXCR4) expression on acute myeloid leukemia (AML) cells correlated with stromal cell derived factor-1α (SDF-1α) and retained hematopoietic progenitors and leukemia cells within the bone marrow microenvironment. Here, we examined CXCR4 expression in 134 de novo AML and 21 controls by flow cytometry, evaluated the relationship between CXCR4 expression and clinical characteristics, and elucidated the prognostic significance of CXCR4 expression in AML prospectively. We found that the CXCR4 expression was significantly higher in AML patients than controls (P = .000). One hundred thirty four cases of de novo AML patients were divided into 2 groups according to the median of CXCR4 relative fluorescence intensity (RFI). CXCR4 high group (RFI >4.23) had markedly shorter overall survival (OS) and disease-free survival (DFS) than CXCR4 low group (RFI ≤4.23) in 106 AML patients who received chemotherapy (P = .002; .026, respectively). Furthermore, in the 87 non-M3 patients who received induction therapy, there was a significant decrease for OS but not for DFS in the CXCR4 high group (P = .047 and .178, respectively). Moreover, high levels of CXCR4 expression independently increased the risk of relapse in both all AML and non-M3 patients who achieved complete remission (CR) after chemotherapy (odds ratio = 1.090, P = .010; odds ratio = 1.068, P = .048, respectively). Collectively, our data suggest that CXCR4 overexpression was an independent prognostic factor for disease relapse and poorer OS in both all AML and non-M3 patients. CXCR4 expression levels can be determined at disease presentation by the flow rapidly and easily. As such, CXCR4 could be used as a potential therapeutic target in AML patients with poor prognosis.

The special stemness functions of Tbx3 in stem cells and cancer development

The T-box factors belong to an ancient protein family, which comprises a cluster of evolutionarily-conserved transcription factors that regulate gene expression and that are crucial to embryonic development. T-box transcription factor 3 (Tbx3) is a member of this family, is expressed in some tissues, and is a key regulator in many critical organs, including the heart, mammary gland, and limbs. Overexpression of Tbx3 is associated with a number of cancers, including head and neck squamous cell carcinoma, gastric, breast, ovary, cervical, pancreatic, bladder and liver cancers, as well as melanoma. Tbx3 promotes tumor development by modulating cell proliferation, tumor formation, metastasis, cell survival and drug resistance. Moreover, there is strong evidence that Tbx3 regulates stem cell maintenance by controlling stem cell self-renewal and differentiation. Verification of the upstream regulatory factors and potential molecular mechanism of Tbx3, being able to explain the function of Tbx3 in carcinogenic effects and stem cell maintenance, will make a valuable contribution to stem cell and cancer research. This review provides an insight into the current research on Tbx3 and explores the significance of Tbx3 in stem cells and tumorigenesis.

When Immune Cells Turn Bad-Tumor-Associated Microglia/Macrophages in Glioma

As a substantial part of the brain tumor microenvironment (TME), glioma-associated microglia/macrophages (GAMs) have an emerging role in tumor progression and in controlling anti-tumor immune responses. We review challenges and improvements of cell models and highlight the contribution of this highly plastic cell population to an immunosuppressive TME, besides their well-known functional role regarding glioma cell invasion and angiogenesis. Finally, we summarize first therapeutic interventions to target GAMs and their effect on the immunobiology of gliomas, focusing on their interaction with T cells.