Cancer-associated fibroblasts impair the cytotoxic function of NK cells in gastric cancer by inducing ferroptosis via iron regulation.

As the predominant immunosuppressive component within the tumor microenvironment (TME), cancer-associated fibroblasts (CAFs) inhibit Natural Killer cell (NK cell) activity to promote tumor progression and immune escape; however, the mechanisms of cross-talk between CAFs and NK cells in gastric cancer (GC) remain poorly understood. In this study, we demonstrate that NK cell levels are inversely correlated with CAFs abundance in human GC. CAFs impair the anti-tumor capacity of NK cells by inducing ferroptosis, a cell death process characterized by the accumulation of iron-dependent lipid peroxides. CAFs induce ferroptosis in NK cells by promoting iron overload; conversely, decreased intracellular iron levels protect NK cells against CAF-induced ferroptosis. Mechanistically, CAFs increase the labile iron pool within NK cells via iron export into the TME, which is mediated by the upregulated expression of iron regulatory genes ferroportin1 and hephaestin in CAFs. Moreover, CAF-derived follistatin like protein 1(FSTL1) upregulates NCOA4 expression in NK cells via the DIP2A-P38 pathway, and NCOA4-mediated ferritinophagy is required for CAF-induced NK cell ferroptosis. In a human patient-derived organoid model, functional targeting of CAFs using a combination of deferoxamine and FSTL1-neutralizing antibody significantly alleviate CAF-induced NK cell ferroptosis and boost the cytotoxicity of NK cells against GC. This study demonstrates a novel mechanism of suppression of NK cell activity by CAFs in the TME and presents a potential therapeutic approach to augment the immune response against GC mediated by NK cells.

Calponin 1 increases cancer-associated fibroblasts-mediated matrix stiffness to promote chemoresistance in gastric cancer.

The mechanical microenvironment regulated by cancer-associated fibroblasts (CAFs) influence tumor progression. Chemotherapeutic interventions including 5-Fluorouracil (5-Fu) are commonly used for primary treatment of patients with advanced gastric cancer (GC), and the development of acquired resistance to 5-Fu limits the clinical efficacy of these chemotherapies. However, if and how the interplay between CAFs and the mechanical microenvironment regulates GC response to 5-Fu is poorly understood. In this study, we demonstrate that high-level expression of calponin 1(CNN1) in gastric CAFs predicts poor clinical outcomes of GC patients, especially for those treated with 5-Fu. CNN1 knockdown in CAFs improves the effectiveness of 5-Fu in reducing tumor growth in a mouse GC model and confers increased sensitivity to 5-Fu in a 3D culture system. Furthermore, CNN1 knockdown impairs CAF contraction and reduces matrix stiffness without affecting the expression of matrix proteins. Mechanistically, CNN1 interacts with PDZ and LIM Domain 7 (PDLIM7) and prevents its degradation by the E3 ubiquitin ligase NEDD4-1, which leads to activation of the ROCK1/MLC pathway. The increased matrix stiffness, in turn, contributes to 5-Fu resistance in GC cells by activating YAP. Taken together, our data reveal a critical role of the mechanical microenvironment in 5-Fu resistance, which is modulated by CNN1hi CAFs-mediated matrix stiffening, indicating that targeting CAFs may provide a novel option for overcoming drug resistance in GC.

On fault-mode phenomenon in no-insulation superconducting magnets: A preventive approach.

Here, we present experimental and analytical results of a preventive approach applied to a fault-mode phenomenon caused by electrodes or power-source failure in a no-insulation (NI) high-temperature superconducting REBa2Cu3O7-x (REBCO, RE = rare earth) magnet. It is generally agreed that the NI magnets, at least those of laboratory scale, are self-protected from overheating and, therefore, from quenching, chiefly because of turn-to-turn current bypassing unique to NI. However, these NI magnets do experience unexpected quenches, e.g., when the current through the magnet suddenly drops due to the aforementioned fault-mode phenomenon. Here, we report this phenomenon of a sudden-discharging-triggered quench of an NI REBCO coil, conduction-cooled, and operated at 4.2 K. We also present our preventive approach for this phenomenon that relies on an appropriately designed resistor shunted across the coil terminals. With this shunt resistor, a quench was prevented by suppressing the quench initiating turn-to-turn heat and induced overcurrent within the NI winding, and the coil current decayed safely.

Vessel state and immune infiltration of the angiogenesis subgroup and construction of a prediction model in osteosarcoma.

Angiogenesis has been recognized as a pivotal contributor to tumorigenesis and progression. However, the role of angiogenesis-related genes (ARGs) in vessel state, immune infiltration, and prognosis remains unknown in osteosarcoma (OS). Bulk RNA sequencing data of osteosarcoma patients were obtained from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database, and patients were divided into two angiogenesis subgroups according to the expression of ARGs. We compared their vessel state and used two independent algorithms to evaluate the tumor microenvironment (TME) in the two subgroups. Furthermore, hub genes of differentially expressed genes (DEGs) in the two subgroups were selected to perform LASSO regression and multivariate Cox stepwise regression, and two prognostic hub genes were found. An ARG_score based on prognostic hub genes was calculated and proved to be reliable in the overall survival prediction in OS patients. Furthermore, the ARG_score was significantly associated with ARGs, immune infiltration, response to immunotherapy, and drug sensitivity. To make our prediction model perform well, clinical features were added and a highly accurate interactive nomogram was constructed. Immunohistochemistry and qRT-PCR were utilized to verify the expression of prognostic hub genes. GSE21257 from the Gene Expression Omnibus (GEO) database was used as a validation dataset to verify its robustness. In conclusion, our comprehensive analysis of angiogenesis subgroups in OS illustrated that angiogenesis may lead to different vessel states and further affect immune infiltration and prognosis of OS patients. Our findings may bring a novel perspective for the immunotherapy strategies for OS patients.

Identification of the Transcription Co-Factor-Related Gene Signature and Risk Score Model for Osteosarcoma.

Osteosarcoma is a malignant tumor with a poor prognosis. Nowadays, there is a lack of good methods to assess the prognosis of osteosarcoma patients. Transcription co-factors (TcoFs) play crucial roles in transcriptional regulation through the interaction with transcription factors (TFs). Many studies have revealed that TcoFs are related to many diseases, especially cancer. However, few studies have been reported about prognostic prediction models of osteosarcoma by using TcoF-related genes. In order to construct a prognostic risk model with TcoF-related genes, the mRNA expression data and matched clinical information of osteosarcoma were downloaded from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database and the Gene Expression Omnibus (GEO) database. TARGET was used as a training set and GSE21257 from GEO was used as a validation set. Univariate Cox regression was performed to select 13 TcoF-related candidate genes, of which five genes (LMO2, MAML3, MTF2, RBPMS, and SIRT1) were finally used to construct the prognostic risk model by LASSO Cox regression analysis. The Kaplan-Meier (K-M) survival curves showed an obvious difference between high- and low-risk groups. The receiver operating characteristic (ROC) curves based on TARGET demonstrated that this risk model was credible (1-year AUC: 0.607; 3-years AUC: 0.713; 5-years AUC: 0.736). Meanwhile, the risk model was associated with immune cells and immune-related functions. By combining the risk score and clinical factors, the nomogram of osteosarcoma was assessed with a C-index of 0.738 to further support the reliability of this 5-gene prognostic risk model. Finally, the expression of TcoF-related genes was validated in different cell lines by quantitative real-time PCR (qRT-PCR) and also in different tissue samples by immunohistochemistry (IHC). In conclusion, the model can predict the prognosis of osteosarcoma patients and may provide novel targets for the treatment of osteosarcoma patients.

Construction and validation of a novel apoptosis-associated prognostic signature related to osteosarcoma metastasis and immune infiltration.

BACKGROUND: Apoptosis played vital roles in the formation and progression of osteosarcoma. However, no studies elucidated the prognostic relationships between apoptosis-associated genes (AAGs) and osteosarcoma. METHODS: The differentially expressed genes associated with osteosarcoma metastasis and apoptosis were identified from GEO and MSigDB databases. The apoptosis-associated prognostic signature was established through univariate and multivariate cox regression analyses. The Kaplan-Meier (KM) survival curve, ROC curve and nomogram were constructed to investigate the predictive value of this signature. CIBERSORT algorithm and ssGSEA were used to explore the relationships between immune infiltration and AAG signature. The above results were validated in another GEO dataset and the expression of AAGs was also validated in osteosarcoma patient samples by immunohistochemistry. RESULTS: HSPB1 and IER3 were involved in AAG signature. In training and validation datasets, apoptosis-associated risk scores were negatively related to patient survival rates and the AAG signature was regarded as the independent prognostic factor. ROC and calibration curves demonstrated the signature and nomogram were reliable. GSEA revealed the signature related to immune-associated pathways. ssGSEA indicated that one immune cell and three immune functions were significantly dysregulated. The immunohistochemistry analyses of patients' samples revealed that AAGs were significantly differently expressed between metastasis and non-metastasis osteosarcomas. CONCLUSIONS: The present study identified and validated a novel apoptosis-associated prognostic signature related to osteosarcoma metastasis. It could serve as the potential biomarker and therapeutic targets for osteosarcoma in the future.

Serum 25-hydroxyvitamin D level is unreliable as a risk factor and prognostic marker in papillary thyroid cancer.

Background: Low levels of vitamin D and altered local vitamin D metabolism have been associated with the prevalence and aggressiveness of several cancers. However, the effect of vitamin D on papillary thyroid cancer (PTC) is controversial. This study aimed to evaluate the impact of preoperative serum vitamin D levels and local vitamin D metabolism on the clinicopathologic characteristics and prognosis of PTC. Methods: In total, 1,578 patients with PTC and 128 patients with benign thyroid diseases were included. Clinical and pathologic data were analyzed to evaluate the role of vitamin D as a risk factor and prognostic marker in PTC. Moreover, a tissue microarray was used to investigate the role of local vitamin D metabolism in PTC progression. Results: Participants with PTC were younger compared to those with benign disease. No significant differences in 25-hydroxy vitamin D [25(OH)D] levels were observed between benign and malignant cases. Among patients with PTC, analyses of prognostic features revealed that decreased 25(OH)D levels were not overtly associated with poor prognosis in PTC. Additionally, local vitamin D metabolism was not associated with the aggressiveness of PTC. Conclusions: Serum 25(OH)D determination may not contribute to risk assessment workup of thyroid nodules. Moreover, decreased preoperative serum vitamin D and local vitamin D metabolism were not associated with poor prognosis of PTC.

The central role of a two-way positive feedback pathway in molecular targeted therapies-mediated pyroptosis in anaplastic thyroid cancer.

BACKGROUND: Anaplastic thyroid carcinoma (ATC) is one of the most aggressive tumours. We previously confirmed that apatinib has potential therapeutic effects on ATC via regulated cell death (RCD). As a newly identified RCD, pyroptosis demonstrates direct antitumour activity different from apoptosis or autophagy. Therefore, the clinical significance, regulatory role and underlying mechanisms of pyroptosis in ATC were focused on in this study. METHODS: In a phase II trial, patients with anaplastic or poorly differentiated thyroid carcinoma received apatinib 500 mg once daily. Multiple assays were implemented to evaluate the antitumour efficacy of apatinib and/or melittin in vitro and in vivo. High-throughput sequencing was applied to analyse differential mRNAs expression in ATC cells treated by apatinib with or without melittin. In situ Hoechst 33342/PI double-staining, LDH release assay and enzyme-linked immunosorbent assay (ELISA) were employed to determine pyroptosis. In mechanism exploration, quantitative RT-PCR, Western blotting and si-RNA knocking down were executed. RESULTS: Seventeen patients were evaluable. Apatinib showed a promising therapeutic effect by a disease control rate (DCR) of 88.2%; however, treatment was terminated in 23.5% of patients due to intolerable toxicity. To reduce adverse events, a pyroptosis-mediated synergistic antitumour effect of apatinib and melittin was identified in treatment of ATC in vitro and in vivo. The caspase-1-gasdermin D (GSDMD) axis-mediated pyroptosis was the key to extra antitumour effect of the combination of apatinib and melittin. Moreover, caspase-3-gasdermin E (GSDME) pyroptosis pathway also functioned importantly in addition to caspase-1-GSDMD pathway. Evidenced by in vitro and in vivo study, a two-way positive feedback interaction was innovatively confirmed between caspase-1-GSDMD and caspase-3-GSDME axes. CONCLUSIONS: Through pyroptosis mediated by caspase-1-GSDMD and caspase-3-GSDME axes synchronically, low-dosage apatinib and melittin could synergistically achieve a comparable therapeutic potential with reduced AEs. More importantly, a two-way positive feedback interaction is innovatively proposed between these two axes, which provide a new prospect of targeted therapy.

Exploration and Validation of a Novel Inflammatory Response-Associated Gene Signature to Predict Osteosarcoma Prognosis and Immune Infiltration.

BACKGROUND: Inflammatory response took part in the progression of tumor and was regarded as the hallmark of cancer. However, the prognostic relationship between osteosarcoma and inflammatory response-associated genes (IRGs) was unclear. This research aimed to explore the correlations between osteosarcoma prognosis and IRG signature. METHODS: The inflammatory response-associated differentially expressed messenger RNAs (DEmRNAs) were screened out through Gene Expression Omnibus (GEO) and Molecular Signature Database (MSigDB) databases. Univariate and multivariate cox regression analyses were utilized to construct the IRG signature. The prognostic value of signature was investigated through Kaplan-Meier (KM) survival curve and nomogram. DEmRNAs among high and low inflammatory response-associated risks were identified and functional enrichment analyses were conducted. ESTIMATE, CIBERSORT and single-sample gene set enrichment analyses (ssGSEA) were implied to reveal the alterations in immune infiltration. All the above results were validated in Target database. The expression of IRGs was also validated in different cell lines by quantitative real-time PCR (qRT-PCR) and osteosarcoma patient samples by immunohistochemistry. RESULTS: The IRG signature that consisted of two genes (MYC, CLEC5A) was established. In training and validation datasets, patients with lower risk scores survived longer and the IRG signature was confirmed as the independent prognostic factor in osteosarcoma. The nomogram was constructed and the calibration curves demonstrated the reliability of this model. Functional analysis of risk score-associated DEmRNAs indicated that immune-related pathways and functions were significantly enriched. ssGSEA revealed that 14 immune cells and 11 immune functions were significantly dysregulated. The qRT-PCR results indicated IRGs were significantly differently expressed in osteosarcoma and osteoblast cell lines. The immunohistochemistry analyses of patients' samples revealed the same result. CONCLUSION: The novel osteosarcoma inflammatory response-associated prognostic signature was established and validated in this study. This model could serve as the biomarker and therapeutic target for osteosarcoma in the future.

FOXK2 transcriptionally activating VEGFA induces apatinib resistance in anaplastic thyroid cancer through VEGFA/VEGFR1 pathway.

Anaplastic thyroid carcinoma (ATC) is a rare and extremely aggressive type of thyroid cancer, and the potential mechanisms involved in ATC progression remains unclarified. In this study, we found that forkhead box K2 (FOXK2) was upregulated in ATC tissues, and the expression of FOXK2 was associated with tumor size. Evidenced by RNA-seq and Chromatin immunoprecipitation (ChIP)-seq assays, FOXK2 positively regulated VEGF and VEGFR signaling network, among which only VEGFA could be noticed in both RNA-seq and ChIP-seq results. ChIP, dual-luciferase reporter system and functional experiments further confirmed that FOXK2 promoted angiogenesis by inducing the transcription of VEGFA. On VEGFR2 blockage by specific targeting agent, such as Apatinib, FOXK2 could rapidly trigger therapeutic resistance. Mechanical analyses revealed that VEGFA transcriptionally induced by FOXK2 could bind to VEGFR1 as a compensation for VEGFR2 blockage, which promoted angiogenesis by activating ERK, PI3K/AKT and P38/MAPK signaling in human umbilical vein endothelial cells (HUVECs). Synergic effect on anti-angiogenesis could be observed when VEGFR1 suppressor AF321 was included in VEGFR2 inhibition system, which clarified the pivot role of FOXK2 in VEGFR2 targeting therapy resistance. More importantly, the binding of VEGFA to VEGFR1 could further promoter FOXK2-mediated VEGFA transcription, which consequently constituted a positive feedback loop. Therefore, the novel loop VEGFA/VEGFR1/FOXK2 functioned importantly in resistance to VEGFR2 targeting therapy in FOXK2+ ATCs. Altogether, FOXK2 plays critical roles in ATC angiogenesis and VEGFR2 blockage resistance by inducing VEGFA transcription. FOXK2 represents a potentially new therapeutic strategy and biomarker for anti-angiogenic therapy against ATC.

The cross-talk between tumor cells and activated fibroblasts mediated by lactate/BDNF/TrkB signaling promotes acquired resistance to anlotinib in human gastric cancer.

Acquired resistance to tyrosine kinase inhibitors (TKIs) is the major obstacle to improve clinical efficacy in cancer patients. The epithelial-stromal interaction in tumor microenvironment influences cancer drug response to TKIs. Anlotinib is a novel oral multi-targeted TKI, and has recently been proven to be effective and safe for several tumors. However, if and how the epithelial-stromal interaction in tumor microenvironment affects anlotinib response in gastric cancer (GC) is not known. In this study, we found that anlotinib inhibited GC cells growth by inducing GC cells apoptosis and G2/M phase arrest in a dose- and time-dependent manner. Reactive oxygen species (ROS) mediated anlotinib-induced apoptosis in GC cells, while cancer-associated fibroblasts (CAFs) significantly suppressed anlotinib-induced apoptosis and ROS in GC cells. Increased BDNF that was derived from CAFs activated TrkB-Nrf2 signaling in GC cells, and reduced GC cells response to anlotinib. We identified secreted lactate from GC cells as the key molecule instructing CAFs to produce BDNF in a NF-κB-dependent manner. Additionally, functional targeting BDNF-TrkB pathway with neutralizing antibodies against BDNF and TrkB increased the sensitivity of GC cells towards anlotinib in human patient-derived organoid (PDO) model. Taken together, these results characterize a critical role of the epithelial-stroma interaction mediated by the lactate/BDNF/TrkB signaling in GC anlotinib resistance, and provide a novel option to overcome drug resistance.

MCM4 Is a Novel Biomarker Associated With Genomic Instability, BRCAness Phenotype, and Therapeutic Potentials in Soft-Tissue Sarcoma.

Soft-tissue sarcoma (STS) is represented by a heterogeneous group of rare malignancies with various molecular oncogenesis. Therapies targeting DNA repair pathways in STS have achieved minimal progress, potentially due to the lack of molecular biomarker(s) beyond the histology subtype. In this report, we comprehensively analyzed the expression profiles of 100 liposarcomas (LPSs), the most common STS subtype, in comparison with 21 adipose tissues from multiple GEO datasets to identify the potential prognostic and therapeutic biomarker for LPS. Furthermore, we investigated TCGA database, our archived tumor samples, and patient-derived tumor cell cultures (PTCCs) as a validation. We identified a total of 69 common differentially expressed genes (DEGs) among public datasets, with mini-chromosome maintenance protein 4 (MCM4) identified as a novel biomarker correlated with patients' clinical staging and survival outcome. MCM4-high expression LPS was characterized by MCM4 copy number increase, genomic instability, and BRCAness phenotype compared with the MCM4-low expression counterpart. In contrast, the mutational and the immune landscape were minimally different between the two groups. Interestingly, the association of MCM4-high expression with genomic instability and BRCAness were not only validated in LPS samples from our institution (n = 66) but also could be expanded to the pan-sarcoma cohort from TCGA database (n = 263). Surprisingly, based on four sarcoma cell lines and eight PTCCs (three LPS and five other sarcoma), we demonstrated that MCM4 overexpression tumors were therapeutically sensitive to PARP inhibitor (PARPi) and platinum chemotherapy, independent of the histology subtypes. Our study, for the first time, suggested that MCM4 might be a novel prognostic biomarker, associated with dysregulated DNA repair pathways and potential therapeutic vulnerability in STS.

The role of anlotinib-mediated EGFR blockade in a positive feedback loop of CXCL11-EGF-EGFR signalling in anaplastic thyroid cancer angiogenesis.

BACKGROUND: Hypoxia-induced angiogenesis functions importantly in anaplastic thyroid cancer (ATC) progression. However, the therapeutic potential of broad-spectrum anti-angiogenic agent remains undefined. Anlotinib conventionally targets VEGFR, FGFR and PDGFR. Here, a novel role of anlotinib on ATC angiogenesis was illustrated. METHODS: Molecular expressions were established via tissue microarray. Multiple assays (tubule formation, 3D sprouting and chicken chorioallantoic membrane model) were used for angiogenic evaluation. Panels of molecular screening were achieved by antibody and PCR arrays. The loop binding motif of EGFR for homology modelling was prepared using Maestro. RESULTS: Anlotinib could dose- and time-dependently inhibit cell viability under normoxia and hypoxia and could repress hypoxia-activated angiogenesis more efficiently in vitro and in vivo. CXCL11 and phospho-EGFR were hypoxia-upregulated with a positive correlation. The cancer-endothelium crosstalk could be mediated by the positive CXCL11-EGF-EGFR feedback loop, which could be blocked by anlotinib directly targeting EGFR via a dual mechanism by simultaneous inhibitory effects on cancer and endothelial cells. The AKT-mTOR pathway was involved in this regulatory network. CONCLUSIONS: The newly identified CXCL11-EGF-EGFR signalling provided mechanistic insight into the interaction between cancer and endothelial cells under hypoxia, and EGFR was a novel target. Anlotinib may be the encouraging therapeutic candidate in ATC.

Development and Validation of a Hypoxia-Associated Prognostic Signature Related to Osteosarcoma Metastasis and Immune Infiltration.

BACKGROUND: Increasing evidence has shown that hypoxia microenvironment relates to tumor initiation and progression. However, no studies focus on the application of hypoxia-associated genes in predicting osteosarcoma patients' prognosis. This research aims to identify the hypoxia-associated genes related to osteosarcoma metastasis and construct a gene signature to predict osteosarcoma prognosis. METHODS: The differentially expressed messenger RNAs (DEmRNAs) related to osteosarcoma metastasis were identified from Therapeutically Applicable Research to Generate Effective Treatments (Target) database. Univariate and multivariate cox regression analyses were performed to develop the hypoxia-associated prognostic signature. The Kaplan-Meier (KM) survival analyses of patients with high and low hypoxia risk scores were conducted. The nomogram was constructed and the gene signature was validated in the external Gene Expression Omnibus (GEO) cohort. Single-sample gene set enrichment analysis (ssGSEA) was conducted to investigate the relationships between immune infiltration and gene signature. RESULTS: Two genes, including decorin (DCN) and prolyl 4-hydroxylase subunit alpha 1 (P4HA1), were involved in the hypoxia-associated gene signature. In training and testing datasets, patients with high-risk scores showed lower survival rates and the gene signature was identified as the independent prognostic factor. Receiver operating characteristic (ROC) curves demonstrated the robustness of signature. Functional analyses of DEmRNAs among high- and low-risk groups revealed that immune-associated functions and pathways were significantly enriched. Furthermore, ssGSEA showed that five immune cells (DCs, macrophages, neutrophils, pDCs, and TIL) and three immune features (CCR, APC co inhibition, and Check-point) were down-regulated in the high-risk group. CONCLUSION: The current study established and validated a novel hypoxia-associated gene signature in osteosarcoma. It could act as a prognostic biomarker and serve as therapeutic guidance in clinical applications.

Tumor suppressor lnc-CTSLP4 inhibits EMT and metastasis of gastric cancer by attenuating HNRNPAB-dependent Snail transcription.

Tumor metastasis is a crucial impediment to the treatment of gastric cancer (GC), and the epithelial-to-mesenchymal transition (EMT) program plays a critical role for the initiation of GC metastasis. Thus, the aim of this study is to investigate the regulation of lnc-CTSLP4 in the EMT process during GC progression. We found that lnc-CTSLP4 was significantly downregulated in GC tumor tissues compared with adjacent non-tumor tissues, and its levels in GC tumor tissues were closely correlated with tumor local invasion, TNM stage, lymph node metastasis, and prognosis of GC patients. Loss- and gain-of-function assays indicated that lnc-CTSLP4 inhibited GC cell migration, invasion, and EMT in vitro, as well as peritoneal dissemination in vivo. Mechanistic analysis demonstrated that lnc-CTSLP4 could bind with Hsp90α/heterogeneous nuclear ribonucleoprotein AB (HNRNPAB) complex and recruit E3-ubiquitin ligase ZFP91 to induce the degradation of HNRNPAB, thus suppressing the transcriptional activation of Snail and ultimately reversing EMT of GC cells. Taken together, our results suggest that lnc-CTSLP4 is significantly downregulated in GC tumor tissues and inhibits metastatic potential of GC cells by attenuating HNRNPAB-dependent Snail transcription via interacting with Hsp90α and recruiting E3 ubiquitin ligase ZFP91, which shows that lnc-CTSLP4 could serve as a prognostic biomarker and therapeutic target for metastatic GC.

FGFR3△7-9 promotes tumor progression via the phosphorylation and destabilization of ten-eleven translocation-2 in human hepatocellular carcinoma.

Overexpression of fibroblast growth factor receptor 3 (FGFR3) correlates with more severe clinical features of hepatocellular carcinoma (HCC). Our previous study has shown that FGFR3∆7-9, a novel splicing mutation of FGFR3, contributes significantly to HCC malignant character, but the epigenetic mechanism is still elusive. In this study, through mass spectrometry and co-immunoprecipitation studies, we discover a close association between FGFR3∆7-9 and the DNA demethylase Ten-Eleven Translocation-2 (TET2). Unlike other certain types of cancer, mutation of TET2 is rare in HCC. However, activation of FGFR3∆7-9 by FGF1 dramatically shortens TET2 half-life. FGFR3∆7-9, but not wild-type FGFR3, directly interacts with TET2 and phosphorylates TET2 at Y1902 site, leading to the ubiquitination and proteasome-mediated degradation of TET2. Overexpression of a phospho-deficient mutant TET2 (Y1902F) significantly reduces the oncogenic potential of FGFR3∆7-9 in vitro and in vivo. Furthermore, FGFR3∆7-9 significantly enhances HCC cell proliferation through the TET2-PTEN-AKT pathway. Specifically, TET2 offsets the elevation of p-AKT level induced by FGFR3∆7-9 through directly binding to PTEN promoter and increasing 5-hmC. Therefore, through phosphorylation and inhibition of TET2, FGFR3∆7-9 reduces PTEN expression and substantiates AKT activation to stimulate HCC proliferation. Together, this study identifies TET2 as a key regulator of the oncogenic role of FGFR3∆7-9 in HCC carcinogenesis and sheds light on new therapeutic strategies for HCC treatment.

Identification and validation of critical alternative splicing events and splicing factors in gastric cancer progression.

Gene expression and alternative splicing (AS) interact in complex ways to regulate biological process which is associated with cancer development. Here, by integrated analysis of gene expression and AS events, we aimed to identify the hub AS events and splicing factors relevant in gastric cancer development (GC). RNA-seq data, clinical data and AS events of 348 GC samples were obtained from the TCGA and TCGASpliceSeq databases. Cox univariable and multivariable analyses, KEGG and GO pathway analyses were performed to identify hub AS events and splicing factor/spliceosome genes, which were further validated in 53 GCs. By bioinformatics methods, we found that gene AS event- and gene expression-mediated GC progression shared the same mechanisms, such as PI3K/AKT pathway, but the involved genes were different. Though expression of 17 hub AS events were confirmed in 53 GC tissues, only 10 AS events in seven genes were identified as critical candidates related to GC progression, notably the AS events (Exon Skip) in CLSTN1 and SEC16A. Expression of these AS events in GC correlated with activation of the PI3K/AKT pathway. Genes with AS events associated with clinical parameters and prognosis were different from the genes whose mRNA levels were related to clinical parameters and prognosis. Besides, we further revealed that QKI and NOVA1 were the crucial splicing factors regulating expression of AS events in GC, but not spliceosome genes. Our integrated analysis revealed hub AS events in GC development, which might be the potential therapeutic targets for GC.

Cathepsin L promotes angiogenesis by regulating the CDP/Cux/VEGF-D pathway in human gastric cancer.

BACKGROUND: Increasing evidence indicates that angiogenesis plays an important role in tumor progression. The function of cathepsin L (CTSL), an endosomal proteolytic enzyme, in promoting tumor metastasis is well recognized. The mechanisms by which CTSL has promoted the angiogenesis of gastric cancer (GC), however, remains unclear. METHODS: The nuclear expression levels of CTSL were assessed in GC samples. The effects of CTSL on GC angiogenesis were determined by endothelial tube formation analysis, HUVEC migration assay, and chick embryo chorioallantoic membrane (CAM) assay. The involvement of the CDP/Cux/VEGF-D pathway was analyzed by angiogenesis antibody array, Western blot, co-immunoprecipitation (Co-IP) and dual-luciferase reporter assay. RESULTS: In this study, we found that the nuclear CTSL expression level in GC was significantly higher than that in adjacent nontumor gastric tissues and was a potential important clinical prognostic factor. Loss- and gain-of-function assays indicated that CTSL promotes the tubular formation and migration of HUVEC cells in vitro. The CAM assay also showed that CTSL promotes angiogenesis of GC in vivo. Mechanistic analysis demonstrated that CTSL can proteolytically process CDP/Cux and produce the physiologically relevant p110 isoform, which stably binds to VEGF-D and promotes the transcription of VEGF-D, thus contributing to the angiogenesis of GC. CONCLUSION: The findings of the present study suggested that CTSL plays a constructive role in the regulation of angiogenesis in human GC and could be a potential therapeutic target for GC.

Differential Targeting of Gr-MDSCs, T Cells and Prostate Cancer Cells by Dactolisib and Dasatinib.

Granulocytic myeloid-derived suppressor cells (Gr-MDSCs) promote immune evasion and resistance to immunotherapeutics in a variety of malignancies. Our previous study showed that dual PI3K/mTOR inhibitor Dactolisib impaired the viability and immunosuppressive function of Gr-MDSCs, and significantly synergized with immune checkpoint blockade (ICB) antibodies targeting PD1 and CTLA4 to eradicate metastatic castration-resistant prostate cancer (CRPC) in a preclinical transgenic mouse model. On the contrary, tyrosine kinase inhibitor Dasatinib diminished tumor-infiltrating T lymphocytes and showed no synergic activity with ICB. The understanding of the distinct effects of Dactolisib and Dasatinib on Gr-MDSCs, T cells and prostate neoplastic cells is inadequate, limiting the clinical translation of the combination immunotherapy. To address this question, we applied Reverse Phase Protein Array (RPPA) to profile 297 proteins and protein phosphorylation sites of Gr-MDSCs, T cells and prostate cancer cells isolated from the CRPC model. We found cell type-specific protein expression patterns and highly selective targets by the two drugs, including preferential inhibition of phospho-4E-BP1 in Gr-MDSCs by Dactolisib and preferential suppression of phospho-Src and phospho-p38 MAPK in T cells. Furthermore, transcriptomic profiling of Gr-MDSCs treated with the two inhibitors revealed downregulation of mitochondrial respiration pathways by Dactolisib but not Dasatinib. Overall, these results provide important mechanistic insight into the efficacious combination of Dactolisib and ICB as well as the detrimental effect of Dasatinib on anti-tumor immunity.

The reciprocal interaction between tumor cells and activated fibroblasts mediated by TNF-α/IL-33/ST2L signaling promotes gastric cancer metastasis.

Gastric cancer (GC) is characterized by extensive local invasion, distant metastasis and poor prognosis. In most cases, GC progression is associated with aberrant expression of cytokines or activation of signaling cascades mediated by tumor-stroma interactions. However, the mechanisms by which these interactions contribute to GC progression are poorly understood. In this study, we find that IL-33 and its receptor ST2L are upregulated in the human GC and served as prognostic markers for poor survival of GC patients. In a co-culture model with GC cells and cancer-associated fibroblasts (CAFs), we further demonstrate that CAFs-derived IL-33 enhances the migration and invasion of GC cells by inducing the epithelial-mesenchymal transition (EMT) through activation of the ERK1/2-SP1-ZEB2 pathway in a ST2L-dependent manner. Furthermore, the secretion of IL-33 by CAFs can be induced by the proinflammatory cytokines TNF-α that is released by GC cells via TNFR2-NF-κB-IRF-1 pathway. Additionally, silencing of IL-33 expression in CAFs or ST2L expression in GC cells inhibits the peritoneal dissemination and metastatic potential of GC cells in nude mice. Taken together, these results characterize a critical role of the interaction between epithelial-stroma mediated by the TNF-α/IL-33/ST2L signaling in GC progression, and provide a rationale for targeting this pathway to treat GC metastasis.