MLLT11/AF1q boosts oncogenic STAT3 activity through Src-PDGFR tyrosine kinase signaling

AF1q is a universal marker of neuroblastoma that sustains N-Myc expression and drives tumorigenesis

Neuroblastoma is the most common extracranial malignant tumor of childhood, accounting for 15% of all pediatric cancer deaths. Despite significant advances in our understanding of neuroblastoma biology, five-year survival rates for high-risk disease remain less than 50%, highlighting the importance of identifying novel therapeutic targets to combat the disease. MYCN amplification is the most frequent and predictive molecular aberration correlating with poor outcome in neuroblastoma. N-Myc is a short-lived protein primarily due to its rapid proteasomal degradation, a potentially exploitable vulnerability in neuroblastoma. AF1q is an oncoprotein with established roles in leukemia and solid tumor progression. It is normally expressed in brain and sympathetic neurons and has been postulated to play a part in neural differentiation. However, no role for AF1q in tumors of neural origin has been reported. In this study, we found AF1q to be a universal marker of neuroblastoma tumors. Silencing AF1q in neuroblastoma cells caused proteasomal degradation of N-Myc through Ras/ERK and AKT/GSK3β pathways, activated p53 and blocked cell cycle progression, culminating in cell death via the intrinsic apoptotic pathway. Moreover, silencing AF1q attenuated neuroblastoma tumorigenicity in vivo signifying AF1q's importance in neuroblastoma oncogenesis. Our findings reveal AF1q to be a novel regulator of N-Myc and potential therapeutic target in neuroblastoma.

A senescence-related signature for predicting the prognosis of breast cancer: A bioinformatics analysis

Breast cancer is a heterogeneous disease with diverse prognosis and treatment outcomes. Current gene signatures for prognostic prediction are limited to specific subtypes of breast cancer. Cellular senescence is a state of irreversible cell cycle arrest that affects various physiological and pathological processes. This study aimed to develop and validate a senescence-related signature for predicting the prognosis of breast cancer patients. We retrieved 744 senescence-associated genes from the SeneQuest database and analyzed their expression profiles in 2 large datasets of breast cancer patients: The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC). We used univariate Cox regression analysis, least absolute shrinkage and selection operator (LASSO) regression, and multivariate Cox regression analysis to derive a 29-gene senescence-related risk signature. The risk signature was significantly associated with disease-specific survival (DSS), clinical characteristics, molecular subtypes, and immune checkpoint genes expressions in both datasets. The risk signature also stratified high-risk and low-risk patients within the same clinical stage and molecular subtype. The risk signature was an independent prognostic factor for breast cancer patients. The senescence-related signature may be a useful biomarker for predicting prognosis and immunotherapy response of breast cancer patients. The risk signature may also guide adjuvant chemotherapy decisions, especially in hormone receptor positive (HR+) and human epidermal growth factor receptor type 2 (HER2)- subtypes.

DriverMP enables improved identification of cancer driver genes

BACKGROUND

Cancer is widely regarded as a complex disease primarily driven by genetic mutations. A critical concern and significant obstacle lies in discerning driver genes amid an extensive array of passenger genes.

FINDINGS

We present a new method termed DriverMP for effectively prioritizing altered genes on a cancer-type level by considering mutated gene pairs. It is designed to first apply nonsilent somatic mutation data, protein‒protein interaction network data, and differential gene expression data to prioritize mutated gene pairs, and then individual mutated genes are prioritized based on prioritized mutated gene pairs. Application of this method in 10 cancer datasets from The Cancer Genome Atlas demonstrated its great improvements over all the compared state-of-the-art methods in identifying known driver genes. Then, a comprehensive analysis demonstrated the reliability of the novel driver genes that are strongly supported by clinical experiments, disease enrichment, or biological pathway analysis.

CONCLUSIONS

The new method, DriverMP, which is able to identify driver genes by effectively integrating the advantages of multiple kinds of cancer data, is available at https://github.com/LiuYangyangSDU/DriverMP. In addition, we have developed a novel driver gene database for 10 cancer types and an online service that can be freely accessed without registration for users. The DriverMP method, the database of novel drivers, and the user-friendly online server are expected to contribute to new diagnostic and therapeutic opportunities for cancers.

Molecular Mechanisms of Anti-Estrogen Therapy Resistance and Novel Targeted Therapies

Breast cancer (BC) is the most commonly diagnosed cancer in women, constituting one-third of all cancers in women, and it is the second leading cause of cancer-related deaths in the United States. Anti-estrogen therapies, such as selective estrogen receptor modulators, significantly improve survival in estrogen receptor-positive (ER+) BC patients, which represents about 70% of cases. However, about 60% of patients inevitably experience intrinsic or acquired resistance to anti-estrogen therapies, representing a major clinical problem that leads to relapse, metastasis, and patient deaths. The resistance mechanisms involve mutations of the direct targets of anti-estrogen therapies, compensatory survival pathways, as well as alterations in the expression of non-coding RNAs (e.g., microRNA) that regulate the activity of survival and signaling pathways. Although cyclin-dependent kinase 4/6 and phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) inhibitors have significantly improved survival, the efficacy of these therapies alone and in combination with anti-estrogen therapy for advanced ER+ BC, are not curative in advanced and metastatic disease. Therefore, understanding the molecular mechanisms causing treatment resistance is critical for developing highly effective therapies and improving patient survival. This review focuses on the key mechanisms that contribute to anti-estrogen therapy resistance and potential new treatment strategies alone and in combination with anti-estrogen drugs to improve the survival of BC patients.

A naturally derived small molecule PSM0537 targets the AF1Q-TCF4 interaction to suppress COX2 expression and inhibit cell proliferation and metastasis in osteosarcoma

ALL1 fused gene from chromosome 1q (AF1Q) functions as an oncogene in several types of cancers, but it has not been observed in osteosarcoma. In this study, we revealed that AF1Q was overexpressed in multiple osteosarcoma cell lines, and its expression level increased with the severity of tumor malignancy in osteosarcoma biopsies. AF1Q was coupled with the transcription factor T cell factor 4 (TCF4) to assemble a complex to bind to the promoter of cyclooxygenase 2 (COX2) and activate its expression. The individual knockdown of AF1Q, TCF4, or COX2 in osteosarcoma cell lines significantly decreased cell proliferation and invasion in vitro. The tumor xenograft model also indicated that the individual knockdown of AF1Q, TCF4, or COX2 could inhibit tumor growth and metastasis. On the basis of these promising results, we established an in vitro AlphaScreen method to identify the compounds that disrupted the AF1Q-TCF4 interaction in a naturally derived small molecule pool. We discovered a compound called PSM0537, which showed a strong ability to inhibit the AF1Q-TCF4 interaction at a low dose of half-maximal inhibitory concentration (IC₅₀) (210.3 ± 15.6 nM). The administration of PSM0537 in vitro and in vivo could dramatically inhibit cell proliferation, invasion, and metastasis. Collectively, our findings reveal that the AF1Q-TCF4 transcriptional complex controls the expression of COX2 and that targeting the AF1Q-TCF4 interaction with PSM0537 could inhibit tumor cell growth and metastasis. Our results provide a new path for chemotherapy of osteosarcoma.

A Phase II Trial of Imatinib Mesylate as Maintenance Therapy for Patients With Newly Diagnosed C-kit-positive Acute Myeloid Leukemia

INTRODUCTION

Adults with acute myeloid leukemia (AML) have a high rate of remission; however, more than 50% relapse. C-kit is expressed in approximately 60% of patients with de novo AML and represents a potential therapeutic target.

MATERIALS AND METHODS

Patients with newly diagnosed AML received 12 months of imatinib mesylate as maintenance therapy after the completion of post-remission therapy. The primary objective was to determine whether this approach improved progression-free survival (defined as no relapse and no death) compared with historical controls.

RESULTS

The median progression-free survival of patients < 60 years of age was 52.1 months (historical control, 13 months) and for patients ≥ 60 years of age was 10.7 months (historical control, 8 months). The median level of AF1q expression was high (9.59), and 84% of patients had moderate or high levels of drug-resistance factors.

CONCLUSIONS

Imatinib maintenance therapy may improve the outcome of newly diagnosed patients with AML who are < 60 years of age.

RAI14 silencing suppresses progression of esophageal cancer via the STAT3 pathway

Esophageal cancer (EC) is an aggressive malignancy that has an unclear molecular pathogenesis. Although retinoic acid induced 14 (RAI14) is involved in various cancer processes, the relationship between EC and RAI14 has not been elucidated. Our study reported the oncogenic function of RAI14 and its underlying mechanisms in EC. The Cancer Genome Atlas (TCGA) database revealed that RAI14 was upregulated in EC, and this upregulation correlated with T stage, histologic grade, and poor clinical prognosis. RAI14 was evaluated in EC cell lines, and the overexpression of RAI14 promoted cell proliferation, migration, and invasion in vitro. Conversely, RAI14 knockdown induced apoptosis and cell cycle arrest. RAI14 activated STAT3, upregulated Mcl-1 and cyclin D1, and inhibited cleaved caspase-3. Inhibition of STAT3 restored the oncogenic effect of RAI14, and RAI14 silencing restrained tumor growth and the protein level of Ki67 in vivo. Our results suggest that RAI14 regulates the STAT3 pathway and acts as an oncogene during EC progression.

Comparative gene expression profiling between optic nerve and spinal cord injury in Xenopus laevis reveals a core set of genes inherent in successful regeneration of vertebrate central nervous system axons

BACKGROUND

The South African claw-toed frog, Xenopus laevis, is uniquely suited for studying differences between regenerative and non-regenerative responses to CNS injury within the same organism, because some CNS neurons (e.g., retinal ganglion cells after optic nerve crush (ONC)) regenerate axons throughout life, whereas others (e.g., hindbrain neurons after spinal cord injury (SCI)) lose this capacity as tadpoles metamorphose into frogs. Tissues from these CNS regions (frog ONC eye, tadpole SCI hindbrain, frog SCI hindbrain) were used in a three-way RNA-seq study of axotomized CNS axons to identify potential core gene expression programs for successful CNS axon regeneration.

RESULTS

Despite tissue-specific changes in expression dominating the injury responses of each tissue, injury-induced changes in gene expression were nonetheless shared between the two axon-regenerative CNS regions that were not shared with the non-regenerative region. These included similar temporal patterns of gene expression and over 300 injury-responsive genes. Many of these genes and their associated cellular functions had previously been associated with injury responses of multiple tissues, both neural and non-neural, from different species, thereby demonstrating deep phylogenetically conserved commonalities between successful CNS axon regeneration and tissue regeneration in general. Further analyses implicated the KEGG adipocytokine signaling pathway, which links leptin with metabolic and gene regulatory pathways, and a novel gene regulatory network with genes regulating chromatin accessibility at its core, as important hubs in the larger network of injury response genes involved in successful CNS axon regeneration.

CONCLUSIONS

This study identifies deep, phylogenetically conserved commonalities between CNS axon regeneration and other examples of successful tissue regeneration and provides new targets for studying the molecular underpinnings of successful CNS axon regeneration, as well as a guide for distinguishing pro-regenerative injury-induced changes in gene expression from detrimental ones in mammals.

A 21‑gene Support Vector Machine classifier and a 10‑gene risk score system constructed for patients with gastric cancer

Gastric cancer (GC) ranks fifth in terms of incidence and third in terms of tumor mortality worldwide. The present study was designed to construct a Support Vector Machine (SVM) classifier and risk score system for GC. The GSE62254 (training set) and GSE26253 (validation set 2) datasets were downloaded from the Gene Expression Omnibus database. Furthermore, the gene expression profile of GC (validation set 1) was obtained from The Cancer Genome Atlas database. Differentially expressed genes (DEGs) between recurrent and non‑recurrent samples were determined using the limma package. The feature genes were selected using the Caret package, and an SVM classifier was built using the e1071 package. Using the penalized package, the optimal predictive genes for constructing a risk score system were screened. Finally, stratification analysis of clinical factors and pathway enrichment analysis were performed using Gene Set Enrichment Analysis. A total of 239 DEGs were identified in GSE62254, among which 114 DEGs were significantly associated with both recurrence‑free survival and overall survival. Subsequently, 21 feature genes were screened from the 114 DEGs, and an SVM classifier was built. A risk score system for survival prediction was constructed, following the selection of 10 optimal genes, including A‑kinase anchoring protein 12, angiopoietin‑like protein 1, cysteine‑rich sequence 1, myeloid/lymphoid or mixed‑lineage leukemia, translocated to chromosome 11, neuron navigator 3, neurobeachin, nephroblastoma overexpressed, pleiotrophin, tumor suppressor candidate 3 and zinc finger and SCAN domain containing 18. The stratification analysis revealed that pathological stage was an independent prognostic clinical factor in the high‑risk group. Additionally, eight significant pathways were associated with the 10‑gene signature. The SVM classifier and risk score system may be applied for classifying and predicting the prognosis of patients with GC, respectively.

The Oncogene AF1Q is Associated with WNT and STAT Signaling and Offers a Novel Independent Prognostic Marker in Patients with Resectable Esophageal Cancer

AF1q impairs survival in hematologic and solid malignancies. AF1q expression is associated with tumor progression, migration, and chemoresistance, and acts as a transcriptional co-activator in WNT and STAT signaling. This study evaluates the role of AF1q in patients with resectable esophageal cancer (EC). A total of 278 patients operated on for esophageal cancer were retrospectively included, and the expression of AF1q, CD44, and pYSTAT3 was analyzed following immunostaining. Quantified data were processed to correlational and survival analysis. In EC patients, an elevated expression of AF1q was associated with CD44 (p = 0.004), and pYSTAT3 (p = 0.0002). High AF1q expression in primary tumors showed high AF1q expression in the corresponding lymph nodes (p= 0.016). AF1q expression was higher after neoadjuvant therapy (p= 0.0002). Patients with AF1q-positive EC relapsed and died earlier compared to patients with AF1q-negative EC (disease-free survival (DFS), p= 0.0005; disease-specific survival (DSS), p= 0.003); in the multivariable Cox regression model, AF1q proved to be an independent prognostic marker (DFS, p= 0.01; DSS, p= 0.03). AF1q is associated with WNT and STAT signaling; it impairs and independently predicts DFS and DSS in patients with resectable EC. The testing of AF1q could facilitate prognosis estimation and provide a possibility of identifying the patients responsive to the therapeutic blockade of its oncogenic downstream targets.

Bosutinib Acts as a Tumor Inhibitor via Downregulating Src/NF-κB/Survivin Expression in HeLa Cells

Efforts have been made to find effective medical drugs for cervical cancer treatment. The incidence of cervical cancer ranks second among women, and is a serious threat to women's health. Aberrant activation of the nonreceptor protein tyrosine kinases such as Src is commonly observed in progressive stages of human tumors. Thus, targeting Src kinase could be a promising strategy for cervical cancer therapy. In this study, we explored the potential utility of bosutinib in the treatment of cervical cancer. We found that bosutinib, as a potent dual Src/Abl inhibitor, could exert anti-tumor effects on cervical cancer. Bosutinib inhibited cervical cancer cells proliferation and colony formation ability in a dose-dependent manner, and also induced apoptosis. Mechanistically, bosutinib effectively decreased the activity of Src/NF-κB/survivin signaling pathway. Our study provided a biological rationale to test bosutinib as a valuable therapeutic option for cervical cancer patients. Anat Rec, 302:2193-2200, 2019. © 2019 American Association for Anatomy.

Recombinant expression and purification of AF1q and its interaction with T-cell Factor 7

The protein ALL1 fused from chromosome 1q (AF1q) is overexpressed in a variety of cancers and acts to activate several signaling pathways that lead to oncogenesis. For example, AF1q has been shown to interact with T-cell Factor 7 (TCF7; also known as TCF1) from the Wnt/β-catenin pathway resulting in the transcriptional activation of the CD44 and the enhancement of breast cancer metastasis. Despite the importance of AF1q in facilitating oncogenesis and metastasis, the structural and biophysical properties of AF1q remain largely unexplored due to the absence of a viable method for producing recombinant protein. Here, we report the overexpression of AF1q in E. coli as a fusion to a N-terminal His₆-tag, which forms inclusion bodies (IBs) during expression. The AF1q protein was purified from IBs under denaturing conditions by immobilized metal affinity chromatography followed by a successful one-step dialysis refolding. Refolded AF1q was further purified to homogeneity by gel filtration chromatography resulting in an overall yield of 35 mg/L culture. Our nuclear magnetic resonance (NMR) and analytical ultracentrifugation (AUC) measurements reveal AF1q interacts with TCF7, specifically with TCF7's high-mobility group (HMG) domain (residues 154-237), which is, to our knowledge, the first biophysical characterization of the AF1q and TCF7 interaction.

Upstream regulators of phosphoinositide 3-kinase and their role in diseases

Phosphoinositide 3-kinase (PI3K), a crucial signaling molecule, is regulated by various upstream regulators. Traditionally, receptor tyrosine kinases and G protein-coupled receptor are regarded as its principle upstream regulators; however, recent reports have indicated that spleen tyrosine kinase, β-arrestin2, Janus kinase, and RAS can also perform this role. Dysregulation of PI3K is common in the progression of various diseases, including, but not limited to, tumors, Alzheimer's disease, Parkinson's disease, rheumatoid arthritis, and acute myelogenous leukemia. The aim of this review is to provide a perspective on PI3K-related diseases examining both the classical and nonclassical upstream regulators of PI3K in detail.

Considering smoking status, coexpression network analysis of non-small cell lung cancer at different cancer stages, exhibits important genes and pathways

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer among smokers, nonsmokers, women, and young individuals. Tobacco smoking and different stages of the NSCLC have important roles in cancer evolution and require different treatments. Existence of poorly effective therapeutic options for the NSCLC brings special attention to targeted therapies by considering genetic alterations. In this study, we used RNA-Seq data to compare expression levels of RefSeq genes and to find some genes with similar expression levels. We utilized the "Weighted Gene Co-expression Network Analysis" method for three different datasets to create coexpressed genetic modules having relations with the smoking status and different stages of the NSCLC. Our results indicate seven important genetic modules having important associations with the smoking status and cancer stages. Based on investigated genetic modules and their biological explanation, we then identified 13 newly candidate genes and 7 novel transcription factors in association with the NSCLC, the smoking status, and cancer stages. We then examined those results using other datasets and explained our results biologically to illustrate some important genes in relation with the smoking status and metastatic stage of the NSCLC that can bring some crucial information about cancer evolution. Our genetic findings also can be used as some therapeutic targets for different clinical conditions of the NSCLC.

AF1q Expression Associates with CD44 and STAT3 and Impairs Overall Survival in Adenoid Cystic Carcinoma of the Head and Neck

Salivary gland malignancies of the head and neck form a heterogeneous group. Adenoid cystic carcinomas are an aggressive entity of salivary gland malignancies characterized by frequent distant metastases and poor response to radio- and chemotherapy. AF1Q is a MLL fusion partner, which can activate Wnt and STAT3 signaling. Recently, overexpression of AF1q has been identified as a poor prognosticator in patients of different malignancies. A total of 46 patients with adenoid cystic carcinoma were immunohistochemically evaluated for expression of AF1q and clinical outcome was analyzed in this context. Additionally, STAT3 and the Wnt downstream target CD44 were investigated and correlated with AF1q. AF1q was overexpressed in 52.2%. Overexpression of AF1q was associated with poorer overall survival (p = 0.03). Additionally, lymph node metastases and solid tumor parts were more frequently observed in AF1qhigh patients (p = 0.07 and 0.05, respectively). AF1q did not influence the occurrence of distant metastases. Expression of AF1q was associated with higher levels of STAT3 and CD44 (p = 0.003 and 0.006, respectively). AF1q is a novel prognostic marker for poor overall survival in adenoid cystic carcinoma patients. The deleterious effects on survival may be a result of promotion of the STAT3 and Wnt pathway.

AF1q inhibited T cell attachment to breast cancer cell by attenuating Intracellular Adhesion Molecule-1 expression

Aim:

To investigate whether AF1q, overexpressed in metastatic cells compared with the primary tumor cells, plays a pivotal role in breast cancer metastasis.

Methods:

To investigate whether AF1q has a responsibility in the acquisition of a metastatic phenotype, we performed RNA-sequencing (RNA-Seq) to identify the gene signature and applied the Metacore direct interactions network building algorithm with the top 40 amplicons of RNA-Seq.

Results:

Most genes were directly linked with intercellular adhesion molecule-1 (ICAM-1). Likewise, we identified that ICAM-1 expression is attenuated in metastatic cells compared to primary tumor cells. Moreover, overexpression of AF1q attenuated ICAM-1 expression, whereas suppression of AF1q elicited the opposite effect. AF1q had an effect on ICAM-1 promoter region and regulated its transcription. Decreased ICAM-1 expression affected the attachment of T cells to a breast cancer cell monolayer. We confirmed the finding by performing the analysis on Burkitt’s lymphoma.

Conclusion:

Attenuation of ICAM-1 by AF1q on tumor cells disadvantages host anti-tumor defenses through the trafficking of lymphocytes, which affects tumor progression and metastasis.

ETS variant 5 promotes colorectal cancer angiogenesis by targeting platelet-derived growth factor BB

ETS transcription factors play important roles in tumor cell invasion, differentiation and angiogenesis. In this study, we initially demonstrated that ETS translocation variant 5 (ETV5) is abnormally upregulated in colorectal cancer (CRC), is positively correlated with CRC tumor size, lymphatic metastasis and tumor node metastasis (TNM) stage and indicates shorter survival and disease-free survival in CRC patients. In vitro and in vivo experiments revealed that the downregulation of ETV5 could significantly suppress CRC cell proliferation. Moreover, overexpression of ETV5 could stimulate CRC angiogenesis in vitro and in vivo, which is consistent with RNA-seq results. Then, we identified platelet-derived growth factor BB (PDGF-BB) as a direct target of ETV5 that plays an important role in ETV5-mediated CRC angiogenesis through an angiogenesis antibody microarray. Additionally, PDGF-BB could activate VEGFA expression via the PDGFR-β/Src/STAT3 pathway in CRC cells and appeared to be positively correlated with ETV5 in CRC tissues. Finally, we revealed that ETV5 could bind directly to the promoter region of PDGF-BB and regulate its expression through ChIP and luciferase assays. Overall, our study suggested that the transcription factor ETV5 could stimulate CRC malignancy and promote CRC angiogenesis by directly targeting PDGF-BB. These findings suggest that EVT5 may be a potential new diagnostic and prognostic marker in CRC and that targeting ETV5 might be a potential therapeutic option for inhibiting CRC angiogenesis.

The effect of a gene associated with retinoid-interferon-induced mortality 19 (GRIM-19) on STAT3-induced gene expression in renal carcinoma

This study aimed to investigate the exact regulatory mechanisms of retinoid-interferon-induced mortality 19 (GRIM-19) in renal carcinoma. Tumour tissue samples from patients with renal carcinoma (n = 30, there were seven cases of Stage I, eight cases of Stage II, eight cases of Stage III, seven cases of Stage IV) and control subjects were selected from adjacent normal tissue (n = 10). Real-time quantitative PCR and western blotting were used to assess the level of GRIM-19, signal transducer and activator of transcription-3 (STAT3) and its downstream molecules. CD31 was detected by immunohistochemistry. The MTT assay was used to measure cell proliferation. The amount of apoptosis cells was analysed by Flow cytometry. The results showed that expression of GRIM-19 was decreased in renal carcinoma. However, in tumour tissue, STAT3 and its downstream signalling molecules showed the higher expression compared with control. Overexpression of GRIM-19, inhibited tumour growth apoptosis by mediating activators of STAT3 signal. In addition, interferon-β and all-trans-retinoic acid inhibited the renal carcinoma cell growth and induced apoptosis, and effect of drug combinations was particularly evident. In conclusion, GRIM-19 expression is associated with hyperactivation of STAT3-induced gene expression in renal carcinoma.

Aryl Hydrocarbon Receptor Promotes IL-10 Expression in Inflammatory Macrophages Through Src-STAT3 Signaling Pathway

The aryl hydrocarbon receptor (AhR) is an important immune regulator with a role in inflammatory response. However, the role of AhR in IL-10 production by inflammatory macrophages is currently unknown. In this study, we investigated LPS-induced IL-10 expression in macrophages from AhR-KO mice and AhR-overexpressing RAW264.7 cells. AhR was highly expressed after LPS stimulation through NF-κB pathway. Loss of AhR resulted in reduced IL-10 expression in LPS-induced macrophages. Moreover, the IL-10 expression was elevated in LPS-induced AhR-overexpressing RAW264.7 cells. Maximal IL-10 expression was dependent on an AhR non-genomic pathway closely related to Src and STAT3. Furthermore, AhR-associated Src activity was responsible for tyrosine phosphorylation of STAT3 and IL-10 expression by inflammatory macrophages. Adoptive transfer of AhR-expressing macrophages protected mice against LPS-induced peritonitis associated with high IL-10 production. In conclusion, we identified the AhR-Src-STAT3-IL-10 signaling pathway as a critical pathway in the immune regulation of inflammatory macrophages, It suggests that AhR may be a potential therapeutic target in immune response.

Novel AF1q/MLLT11 favorably affects imatinib resistance and cell survival in chronic myeloid leukemia

Tyrosine kinase inhibitor treatment of chronic myeloid leukemia (CML) has demonstrated beneficial effects. However, resistance to tyrosine kinase inhibitors and disease relapse are still a challenge for CML therapy. In this study, we analyzed bone marrow samples from 149 CML patients and 15 control donors, and investigated the affect of AF1q on CML cell survival and engraftment in vitro and in vivo. We found that AF1q/MLLT11 expression was significantly upregulated in CML patients, especially in CD34⁺ CML cells. Elevated AF1q expression was associated with disease progression. Knockdown of AF1q enhanced imatinib sensitivity, induced apoptosis, and suppressed growth in CML cells. Moreover, AF1q deficiency sensitized CD34⁺ CML cells to imatinib. In contrast, upregulation of AF1q promoted cell survival, protected CML cells from imatinib-induced apoptosis, and increased engraftment of CML cells in vivo. We further identified a positive correlation between AF1q and CD44 expression in chronic phase CML patients and CD34⁺ CML cells. Importantly, AF1q contributes to imatinib-resistance in CML by regulating the expression of CD44. These findings reveal a novel BCR-ABL-independent pathway, AF1q/CD44, involves imatinib resistance in CML, thus representing a potential therapeutic target for imatinib-resistant CML patients.

Serum cytokine levels in breast cancer patients during neoadjuvant treatment with bevacizumab

A high concentration of circulating vascular endothelial growth factor (VEGF) in cancer patients is associated with an aggressive tumor phenotype. Here, serum levels of 27 cytokines and blood cell counts were assessed in breast cancer patients receiving neoadjuvant chemotherapy with or without bevacizumab (Bev) in a randomized cohort of 132 patients with non-metastatic HER2-negative tumors. Cytokine levels were determined prior to treatment and at various time-points. The cytotoxic chemotherapy regimen of fluorouracil, epirubicin, and cyclophosphamide (FEC) had a profound impact on both circulating white blood cells and circulating cytokine levels. At the end of FEC treatment, the global decrease in cytokine levels correlated with the drop in white blood cell counts and was significantly greater in the patients of the Bev arm for cytokines, such as VEGF-A, IL-12, IP-10 and IL-10. Among patients who received Bev, those with pathological complete response (pCR) exhibited significantly lower levels of VEGF-A, IFN-γ, TNF-α and IL-4 than patients without pCR. This effect was not observed in the chemotherapy-only arm. Certain circulating cytokine profiles were found to correlate with different immune cell types at the tumor site. For the Bev arm patients, the serum cytokine levels correlated with higher levels of cytotoxic T cells at the end of the therapy regimen, which was indicative of treatment response. The higher response rate for Bev-treated patients and stronger correlations between serum cytokine levels and infiltrating CD8T cells merits further investigation.

Tyrosine kinase inhibitor-induced IL-6/STAT3 activation decreases sensitivity of EGFR-mutant non-small cell lung cancer to icotinib

Tyrosine kinase Inhibitors (TKIs) of epidermal growth factor receptor (EGFR) has considerably benefited for non-small cell lung carcinomas (NSCLC) harbor mutations in EGFR. However, the factors attenuating EGFR-TKI efficiency are obstacles to inhibit the proliferation of EGFR-mutant NSCLC cells successfully. Clarifying the insensitivity mechanisms of EGFR-TKI would help to develop new treatment strategy. In this study, the sensitivity of EGFR-mutant NSCLC cell lines, PC9 and HCC827, to icotinib was detected. Similar with other EGFR-TKIs such as gefitinib and erlortinib in previous research, the proliferation of two cell lines was apparently inhibited. However, we surprisingly found that contrast with the suppression of EGFR-AKT/ERK pathway, STAT3 was significantly activated in PC9 cells with the treatment of icotinib, but not in HCC827 cells. Further study confirmed that icotinib concomitantly induced IL-6 secretion and src activation in PC9 cells. Moreover, with the treatment of IL-6 neutralizing antibody or src inhibitor, dasatinib, icotinib-induced phosphorylation of STAT3 was reduced, as well as the sensitivity of PC9 to icotinib was also partially increased. Our results suggest that Src/IL-6/STAT3 bypass pathway is activated to maintain cell survival when the EGFR pathway was inhibited by TKIs, even in some EGFR-mutant NSCLC cells sensitive to TKIs. This finding provides a groundwork for potential combinatorial treatment with TKIs and Src or STAT3 inhibitor to improve icotinib sensitivity.

Novel Src/Abl tyrosine kinase inhibitor bosutinib suppresses neuroblastoma growth via inhibiting Src/Abl signaling

Neuroblastoma (NB) is the most common extracranial solid tumor in children. Aberrant activation of the non-receptor tyrosine kinases Src and c-Abl contributes to the progression of NB. Thus, targeting these kinases could be a promising strategy for NB therapy. In this paper, we report that the potent dual Src/Abl inhibitor bosutinib exerts anti-tumor effects on NB. Bosutinib inhibited NB cell proliferation in a dose-dependent manner and suppressed colony formation ability of NB cells. Mechanistically, bosutinib effectively decreased the activity of Src/Abl and PI3K/AKT/mTOR, MAPK/ERK, and JAK/STAT3 signaling pathways. In addition, bosutinib enhanced doxorubicin (Dox)- and etoposide (VP-16)-induced cytotoxicity in NB cells. Furthermore, bosutinib demonstrated anti-tumor efficacy in an orthotopic xenograft NB mouse model in a similar mechanism as of that in vitro. In summary, our results reveal that Src and c-Abl are potential therapeutic targets in NB and that the novel Src/Abl inhibitor bosutinib alone or in combination with other chemotherapeutic agents may be a valuable therapeutic option for NB patients.

Receptor tyrosine kinases (RTKs) in breast cancer: signaling, therapeutic implications and challenges

Breast cancer is a multifactorial disease and driven by aberrant regulation of cell signaling pathways due to the acquisition of genetic and epigenetic changes. An array of growth factors and their receptors is involved in cancer development and metastasis. Receptor Tyrosine Kinases (RTKs) constitute a class of receptors that play important role in cancer progression. RTKs are cell surface receptors with specialized structural and biological features which respond to environmental cues by initiating appropriate signaling cascades in tumor cells. RTKs are known to regulate various downstream signaling pathways such as MAPK, PI3K/Akt and JAK/STAT. These pathways have a pivotal role in the regulation of cancer stemness, angiogenesis and metastasis. These pathways are also imperative for a reciprocal interaction of tumor and stromal cells. Multi-faceted role of RTKs renders them amenable to therapy in breast cancer. However, structural mutations, gene amplification and alternate pathway activation pose challenges to anti-RTK therapy.

Involvement of AF1q/MLLT11 in the progression of ovarian cancer

The functional role of AF1q/MLLT11, an oncogenic factor involved in a translocation t(1;11)(q21;q23) responsible for acute myeloid leukaemia, has been investigated in hematological and solid malignancies and its expression was found to be linked to tumor progression and poor clinical outcome. In addition to its oncogenic function, AF1q has been shown to play a role in the onset of basal and drug-induced apoptosis in cancer cells of different histotypes, including ovarian cancer. Through in vitro, ex vivo, and in silico approaches, we demonstrated here that AF1q is also endowed with protumorigenic potential in ovarian cancer. In ovarian cancer cell lines, stable AF1q overexpression caused activation of epithelial-to-mesenchymal transition and increased motility/migratory/invasive abilities accompanied by gene expression changes mainly related to Wnt signaling and to signaling pathways involving in ERK/p38 activation. The potential role of AF1q in ovarian cancer progression was confirmed by immunohistochemical and in silico analyses performed in ovarian tumor specimens which revealed that the protein was absent in normal ovarian epithelium and became detectable when atypical proliferation was present. Moreover, AF1q was significantly lower in borderline ovarian tumors (i.e., tumors of low malignant potential without stromal invasion) than in invasive tumors, thus corroborating the association between high AF1q expression and increased migratory/invasive cell behavior and confirming its potential role in ovarian cancer progression. Our findings demonstrated, for the first time, that AF1q is endowed with protumorigenic activity in ovarian cancer, thus highlighting a dual behavior (i.e., protumorigenic and proapoptotic functions) of the protein in the malignancy.

AF1q Mediates Tumor Progression in Colorectal Cancer by Regulating AKT Signaling

The up-regulation of ALL1-fused gene from chromosome 1q (AF1q) is commonly seen in aggressive hematologic malignancies as well as in several solid tumor tissues. However, its expression and intrinsic function in human colorectal cancer (CRC) remains largely undefined. To explore the role of AF1q in human CRC progression, AF1q expression was analyzed in human CRC tissue samples and CRC cell lines. Clinical specimens revealed that AF1q was up-regulated in human CRC tissues, and that this up-regulation was associated with tumor metastasis and late tumor, lymph node, metastasis (TNM) stage. AF1q knockdown by shRNA inhibited tumor cell proliferation, migration, invasion, and epithelial-mesenchymal transition in vitro, as well as tumorigenesis and liver metastasis in vivo, whereas these effects were reversed following AF1q overexpression. These AF1q-mediated effects were modulated by the protein kinase B (AKT) signaling pathway, and inhibition of AKT signaling attenuated AF1q-induced tumor promotion. Thus, AF1q contributes to CRC tumorigenesis and progression through the activation of the AKT signaling pathway. AF1q might therefore serve as a promising new target in the treatment of CRC.