IL‐15 regulates Bcl‐2 family members Bim and Mcl‐1 through JAK/STAT and PI3K/AKT pathways in T cells

Maintenance of T cells is determined by their survival capacity, which is regulated by Bcl‐2 proteins. Cytokines signalling through the common gamma chains such as IL‐2, IL‐7 and IL‐15 are important for T‐cell survival but how these cytokines determine the expression of Bcl‐2‐family proteins is not clear. We report signalling events of cytokines that regulate expression of two key Bcl‐2 proteins, pro‐apoptotic Bim and anti‐apoptotic Mcl‐1, in resting C57BL/6 mouse T cells. IL‐2, IL‐7 and IL‐15 inhibited apoptosis but paradoxically induced the expression of Bim, countered by concomitant induction of Mcl‐1. Bim induction by IL‐15 was found at the mRNA and protein levels and depended on both JAK/STAT and PI3K signals. A new STAT5‐binding site was identified in the Bim promoter, which was occupied by STAT5 upon IL‐15 stimulation. Although it also depended on JAK/STAT‐ and PI3K signalling, Mcl‐1 regulation was independent of Mcl‐1 mRNA levels and of regulation of protein stability, suggesting translational regulation. Concurrent CD3 signals inhibited some of the IL‐7 effect but not the IL‐15 effect on Bcl‐2 proteins. The data suggest that cytokines induce Bim and prime T cells for apoptosis, but also inhibit apoptosis by stabilising Mcl‐1. Later downregulation of short‐lived Mcl‐1 may induce efficient, Bim‐dependent apoptosis.     

不同化疗药物对结肠癌细胞获得性TRAIL基因耐药的逆转作用

目的：探讨不同化疗药物对结肠癌DLD1细胞获得性TRAIL基因耐药的逆转作用及其可能的机制。 方法：将不同化疗药物联合重组腺病毒载体（Ad）介导的TRAIL基因处理对Ad/gTRAIL耐药的结肠癌DLD1-TRAIL/R细胞，通过MTT法检测治疗后肿瘤细胞的存活率，以评价化疗药物对TRAIL基因耐药的逆转作用；然后进一步在体内评价该逆转策略的有效性；接着通过Western免疫印迹等方法探讨逆转耐药的可能机制。结果：在体外检测了5-氟脲嘧啶、丝裂霉素、阿霉素、氟脲苷、依立替康以及顺铂6种化疗药物对DLD1-TRAIL/R细胞TRAIL基因耐药的逆转作用，结果发现只有5-氟脲嘧啶和丝裂霉素能够使DLD1-TRAIL/R细胞对Ad/gTRAIL重新敏感。进一步的结果表明联合5-氟脲嘧啶和Ad/gTRAIL能在体内有效地抑制DLD1-TRAIL/R细胞来源的肿瘤生长，且该抑制作用明显强于其它对照组。结论：联合使用Ad/gTRAIL和5-氟脲嘧啶或丝裂霉素能在体内外有效地逆转DLD1-TRAIL/R细胞对TRAIL基因的获得性耐药，其中丝裂霉素的逆转作用可能与其诱导的Bax过度表达有关。     

白藜芦醇增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用

目的:观察白藜芦醇作用前后TRAIL对人髓系白血病KG-1a细胞的细胞毒作用的变化。方法:流式细胞仪检测KG-1a细胞表面CD34和CD38的表达,二甲氧唑黄(XTT)细胞增殖及细胞毒性检测试剂盒检测白藜芦醇作用前后TRAIL对KG-1a细胞增殖的影响,AnnexinV-FITC/PI染色流式细胞仪检测细胞凋亡变化。流式细胞仪检测白藜芦醇作用前后KG-1a细胞表面TRAIL死亡受体表达变化。结果:人髓系白血病KG-1a细胞CD34+CD38-占(58.67±2.87)%,10~1 000 ng/ml的TRAIL对KG-1a细胞增殖无明显影响,但对白藜芦醇作用后的KG-1a细胞的增殖有明显抑制作用,白藜芦醇能促进TRAIL诱导KG-1a细胞凋亡,并能上调KG-1a细胞表面TRAIL死亡受体DR5的表达。结论:白藜芦醇能增强TRAIL对人髓系白血病KG-1a细胞的细胞毒作用,其机制可能与白藜芦醇上调KG-1a细胞表面TRAIL死亡受体DR5的表达有关。     

TRAIL receptor deficiency sensitizes mice to dextran sodium sulphate‐induced colitis and colitis‐associated carcinogenesis

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor (TRAIL-R) play important roles in immune regulation and cancer cell death. Although TRAIL has been shown to induce chemokine release in various tumour cells, the function of TRAIL-R in the development of colitis and colitis-associated carcinogenesis has not been explored. In this study, we found that TRAIL-R-deficient mice exhibited a higher incidence of colitis and colitis-associated cancer than that of wild-type (WT) mice, and TRAIL-R expression was down-regulated in WT mice that were fed dextran sulphate sodium. Chemokines, including CCL2 and CXCL1, were highly expressed in the serum and inflammatory colon tissues of TRAIL-R^−/− mice compared with WT mice, and TRAIL-R^−/− mice showed a marked infiltration of immune cells during colitis. Hyperactivation of Janus kinase and nuclear factor-κB in colon epithelial cells was also observed, which correlated with the severity of colonic inflammation in TRAIL-R^−/− mice. These data suggest that TRAIL-R plays a protective role in chemical-induced colon injury and negatively regulates mucosal immune responses.     

Interleukin‐15‐activated natural killer cells kill autologous osteoclasts via LFA‐1, DNAM‐1 and TRAIL,and inhibit osteoclast‐mediated bone erosion in vitro

Osteoclasts reside on bone and are the main bone resorbing cells playing an important role in bone homeostasis, while natural killer (NK) cells are bone‐marrow‐derived cells known to play a crucial role in immune defence against viral infections. Although mature NK cells traffic through bone marrow as well as to inflammatory sites associated with enhanced bone erosion, including the joints of patients with rheumatoid arthritis, little is known about the impact NK cells may have on mature osteoclasts and bone erosion. We studied the interaction between human NK cells and autologous monocyte‐derived osteoclasts from healthy donors in vitro. We show that osteoclasts express numerous ligands for receptors present on activated NK cells. Co‐culture experiments revealed that interleukin‐15‐activated, but not resting, NK cells trigger osteoclast apoptosis in a dose‐dependent manner, resulting in drastically decreased bone erosion. Suppression of bone erosion requires contact between NK cells and osteoclasts, but soluble factors also play a minor role. Antibodies masking leucocyte function‐associated antigen‐1, DNAX accessory molecule‐1 or tumour necrosis factor‐related apoptosis‐inducing ligand enhance osteoclast survival when co‐cultured with activated NK cells and restore the capacity of osteoclasts to erode bone. These results suggest that interleukin‐15‐activated NK cells may directly affect bone erosion under physiological and pathological conditions.     

Identification of DJ‐1 as a contributor to multidrug resistance in human small‐cell lung cancer using proteomic analysis

Proteomic approaches have been proven to provide an important tool in identifying drug resistance‐associated proteins. The aim of this study was to investigate the protein profiling of drug resistance‐related proteins in small‐cell lung cancer (SCLC) by proteomic analysis. The proteomic profiling was performed by two‐dimensional fluorescence difference gel electrophoresis (2D‐DIGE) coupled with MALDI‐TOF‐TOF of SCLC in the multidrug‐resistant cell line H69AR and its parental cell line H69. A total of 11 proteins were identified to be >2‐fold up‐or downregulated between the two cell lines. DJ‐1, one of the differently expressed proteins identified by proteomics, was further examined by immunohistochemistry staining in 116 cases of SCLC tissues. Immunohistochemical results demonstrated that DJ‐1 was expressed in 51.7% (60/116) of SCLC. DJ‐1 expression was correlated significantly with survival time of SCLC patients (P < 0.05), but not with other clinical parameters such as gender, age and clinical stage (P > 0.05). Downregulation of DJ‐1 using DJ‐1‐siRNA in H69AR cells sensitized cancer cells to chemotherapeutic drugs through increasing drug‐induced cell apoptosis accompanied with G0‐G1 phase arrest. These findings suggest DJ‐1 may serve as a potential biomarker for chemoresistance and prognostic factor for patients with SCLC.     

Gemcitabine sensitizes lung cancer cells to Fas/FasL system‐mediated killing

Gemcitabine is a chemotherapy agent commonly used in the treatment of non‐small cell lung cancer (NSCLC) that has been demonstrated to induce apoptosis in NSCLC cells by increasing functionally active Fas expression. The aim of this study was to evaluate the Fas/Fas ligand (FasL) system involvement in gemcitabine‐induced lung cancer cell killing. NSCLC H292 cells were cultured in the presence or absence of gemcitabine. FasL mRNA and protein were evaluated by real‐time PCR, and by Western blot and flow cytometry, respectively. Apoptosis of FasL‐expressing cells was evaluated by flow cytometry, and caspase‐8 and caspase‐3 activation by Western blot and a colorimetric assay. Cytotoxicity of lymphokine‐activated killer (LAK) cells and malignant pleural fluid lymphocytes against H292 cells was analysed in the presence or absence of the neutralizing anti‐Fas ZB4 antibody, by flow cytometry. Gemcitabine increased FasL mRNA and total protein expression, the percentage of H292 cells bearing membrane‐bound FasL (mFasL) and of mFasL‐positive apoptotic H292 cells, as well as caspase‐8 and caspase‐3 cleavage. Moreover, gemcitabine increased CH11‐induced caspase‐8 and caspase‐3 cleavage and proteolytic activity. Cytotoxicity of LAK cells and pleural fluid lymphocytes was increased against gemcitabine‐treated H292 cells and was partially inhibited by ZB4 antibody. These results demonstrate that gemcitabine: (i) induces up‐regulation of FasL in lung cancer cells triggering cell apoptosis via an autocrine/paracrine loop; (ii) induces a Fas‐dependent apoptosis mediated by caspase‐8 and caspase‐3 activation; (iii) enhances the sensitivity of lung cancer cells to cytotoxic activity of LAK cells and malignant pleural fluid lymphocytes, partially via Fas/FasL pathway. Our data strongly suggest an active involvement of the Fas/FasL system in gemcitabine‐induced lung cancer cell killing.     

Anticancer activity of NOB1-targeted shRNA combination with TRAIL in epithelial ovarian cancer cells

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) based strategy is a promising targeted therapeutic approach for the treatment of ovarian cancer. However, the effectiveness of the treatment remains limited due to the inherent or acquired resistance of tumor cells to TRAIL. Our previously study demonstrated that downregulation of NOB1 (NIN1/RPN12 binding protein 1 homolog) expression by a lentiviral short hairpin RNA (shRNA) delivery system (Lv/sh-NOB1) suppressed ovarian cancer growth. Here, Lv/sh-NOB1 and TRAIL were combined and tested the effects of this combination on ovarian cancer cells to identify more effective therapeutics against ovarian cancer by several in vitro experiments. Tumor growth ability in SKVO3 xenograft nude mice was also determined to define this combination treatment effect in tumorigenesis in vivo. In vitro assay showed that Lv/sh-NOB1 in combination with TRAIL treatment in ovarian cancer cell synergistically suppressed the proliferation and colony formation, as well as induced cell apoptosis and increased the activity of caspase-3, -8 and -9. In vivo assay showed that Lv/sh-NOB1 combination with TRAIL synergistically suppressed tumor growth of nude mice model. Importantly, we found that downregulation of NOB1 could upregulate DR5 expression and active MAPK pathway, which might contribute to increase sensitivity TRAIL to ovarian cancer cells. These findings suggested that Lv/sh-NOB1 combination with TRAIL treatment may be a potential treatment approach for ovarian cancer.     

Targeting galectin‐1‐induced angiogenesis mitigates the severity of endometriosis

Endometriosis is characterized by the presence of endometrial tissue outside the uterus that causes severe pelvic pain and infertility in women of reproductive age. Although not completely understood, the pathophysiology of the disease involves chronic dysregulation of inflammatory and vascular signalling. In the quest for novel therapeutic targets, we investigated the involvement of galectin‐1 (Gal‐1), an endogenous glycan‐binding protein endowed with both immunosuppressive and pro‐angiogenic activities, in the pathophysiology of endometriotic lesions. Here we show that Gal‐1 is selectively expressed in stromal and endothelial cells of human endometriotic lesions. Using an experimental endometriosis model induced in wild‐type and Gal‐1‐deficient (Lgals1^?/?) mice, we showed that this lectin orchestrates the formation of vascular networks in endometriotic lesions in vivo, facilitating their ectopic growth independently of vascular endothelial growth factor (VEGF) and the keratinocyte‐derived CXC‐motif (CXC‐KC) chemokine. Targeting Gal‐1 using a specific neutralizing mAb reduced the size and vascularized area of endometriotic lesions within the peritoneal compartment. These results underline the essential role of Gal‐1 during endometriosis and validate this lectin as a possible target for the treatment of disease. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Syndecan‐1 (CD138) contributes to prostate cancer progression by stabilizing tumour‐initiating cells

Increasing evidence suggests that tumour‐initiating cells (TICs) contribute to the development of prostate cancer. Here, we identified syndecan‐1 as a key molecule maintaining the stability of prostate cancer TICs. Holoclones harbouring the biological properties of stemness were derived from single‐cell cultures of the PC3 human prostate cancer cell line. These holoclones over‐expressed syndecan‐1, but showed reduced expression of NADPH oxidase (NOX) and synthesis of hydrogen peroxide and oxygen radicals. Stable RNA‐mediated silencing of syndecan‐1 gene expression up‐regulated NOX‐dependent generation of reactive oxygen species and reduced the survival of holoclones in vitro. Syndecan‐1 down‐regulation also strongly reduced the number of CD133⁺/CD44⁺ primitive cancer cells and tumour growth in vivo. Interestingly, syndecan‐1 gene knockdown significantly enhanced the tumour‐suppressive effects of docetaxel by inhibiting the docetaxel‐induced increase in CD133⁺/CD44⁺ cells in vivo. In the transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model of prostate cancer, early intervention with a syndecan‐1 inhibitor (OGT2115) or syndecan‐1 RNAi reduced the incidence of adenocarcinoma and the number of c‐kit⁺/CD44⁺ cells in cancer foci. Finally, we found that syndecan‐1 immunopositivity in prostate cancer cells was significantly associated with biochemical recurrence after radical prostatectomy. Taken together, our results show that syndecan‐1 contributes to prostatic carcinogenesis by maintaining TICs and may be a target molecule for therapy. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Thymidylate synthase is functionally associated with ZEB1 and contributes to the epithelial‐to‐mesenchymal transition of cancer cells

Thymidylate synthase (TS) is a fundamental enzyme of nucleotide metabolism and one of the oldest anti‐cancer targets. Beginning from the analysis of gene array data from the NCI‐60 panel of cancer cell lines, we identified a significant correlation at both gene and protein level between TS and the markers of epithelial‐to‐mesenchymal transition (EMT), a developmental process that allows cancer cells to acquire features of aggressiveness, like motility and chemoresistance. TS levels were found to be significantly augmented in mesenchymal‐like compared to epithelial‐like cancer cells, to be regulated by EMT induction, and to negatively correlate with micro‐RNAs (miRNAs) usually expressed in epithelial‐like cells and known to actively suppress EMT. Transfection of EMT‐suppressing miRNAs reduced TS levels, and a specific role for miR‐375 in targeting the TS 3'‐untranslated region was identified. A particularly relevant association was found between TS and the powerful EMT driver ZEB1, the shRNA‐mediated knockdown of which up‐regulated miR‐375 and reduced TS cellular levels. The TS–ZEB1 association was confirmed in clinical specimens from lung tumours and in a genetic mouse model of pancreatic cancer with ZEB1 deletion. Interestingly, TS itself appeared to have a regulatory role in EMT in cancer cells, as TS knockdown could directly reduce the EMT phenotype, the migratory ability of cells, the expression of stem‐like markers, and chemoresistance. Taken together, these data indicate that the TS enzyme is functionally linked with EMT and cancer differentiation, with several potential translational implications. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

ERRα augments HIF‐1 signalling by directly interacting with HIF‐1α in normoxic and hypoxic prostate cancer cells

Adaptation of cancer cells to a hypoxic microenvironment is important for their facilitated malignant growth and advanced development. One major mechanism mediating the hypoxic response involves up‐regulation of hypoxia‐inducible factor 1 (HIF‐1) expression, which controls reprogramming of energy metabolism and angiogenesis. Oestrogen‐related receptor‐α (ERRα) is a pivotal regulator of cellular energy metabolism and many biosynthetic pathways, and has also been proposed to be an important factor promoting the Warburg effect in advanced cancer. We and others have previously shown that ERRα expression is increased in prostate cancer and is also a prognostic marker. Here we show that ERRα is oncogenic in prostate cancer and also a key hypoxic growth regulator. ERRα‐over‐expressing prostate cancer cells were more resistant to hypoxia and showed enhanced HIF‐1α protein expression and HIF‐1 signalling. These effects could also be observed in ERRα‐over‐expressing cells grown under normoxia, suggesting that ERRα could function to pre‐adapt cancer cells to meet hypoxia stress. Immunoprecipitation and FRET assays indicated that ERRα could physically interact with HIF‐1α via its AF‐2 domain. A ubiquitination assay showed that this ERRα–HIF‐1α interaction could inhibit ubiquitination of HIF‐1α and thus reduce its degradation. Such ERRα–HIF‐1α interaction could be attenuated by XCT790, an ERRα‐specific inverse agonist, resulting in reduced HIF‐1α levels. In summary, we show that ERRα can promote the hypoxic growth adaptation of prostate cancer cells via a protective interaction with HIF‐1α, suggesting ERRα as a potential therapeutic target for cancer treatment. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

The cyclin‐dependent kinase inhibitor R‐roscovitine down‐regulates Mcl‐1 to override pro‐inflammatory signalling and drive neutrophil apoptosis

Successful resolution of inflammation requires inflammatory cells such as neutrophils to undergo apoptosis prior to non‐inflammatory phagocytosis by professional phagocytes. Recently, cyclin‐dependent kinase (CDK) inhibitors (e.g. R‐roscovitine) have been shown to induce neutrophil apoptosis and enhance the resolution of inflammation. Interestingly, NF‐κB and MAPK pathways and key endogenous survival proteins (typified by Mcl‐1) are involved in the regulation of neutrophil apoptosis and, in cancer‐cell lines, have been implicated as possible targets of CDK inhibitors. Here, we demonstrate that R‐roscovitine over‐rides TNF‐α and LPS‐induced survival (determined by morphological examination and binding of fluorescently labelled annexin‐V) of isolated peripheral blood neutrophils. This effect did not appear to be mediated via effects on early markers of neutrophil activation (e.g. surface marker expression, shape change, aggregation and superoxide anion generation), by direct inhibition of NF‐κB activation (assessed by cytoplasmic IκBα proteolysis and NF‐κB p65 subunit translocation) and ERK activation (determined by specific ERK phosphorylation) but due to down‐regulation (at protein and mRNA level) of the survival protein Mcl‐1 but not the pro‐apoptotic bcl‐2 homologue Bim. These findings suggest that key endogenous survival proteins may be the targets of CDK inhibitors and consequently may be of critical importance in the resolution of inflammation.     

Coexistence of MACC1 and NM23‐H1 dysregulation and tumor budding promise early prognostic evidence for recurrence risk of early‐stage colon cancer

The tumor‐node‐metastasis (TNM) classification, the presence of a mucinous component, and signet ring cells are well‐known criteria for identifying patients at a high risk for recurrence and determining the therapeutic approach for early‐stage colon cancer (eCC). Nevertheless, recurrence can unexpectedly occur in some eCC cases after surgical resection. The aims of the present study were to evaluate the relation of dysregulated MACC1, c‐MET, and NM23‐H1 expression with the histopathological features of tumors in recurrence formation in eCC cases. A total of 100 sporadic eCC patients without poor prognosis factors were evaluated in this study. The relationship between the altered expression of MACC1, c‐MET, and NM23‐H1 and pathological microenvironmental features, including the presence of tumor budding and desmoplasia, were assessed. The primary outcomes, including 5‐year overall survival (OS) and disease‐free survival (DFS), were also measured. Compared with nonrecurrent patients, the expression level of MACC1 was 8.27‐fold higher, and NM23‐H1 was 11.36‐fold lower in patients with recurrence during the 5‐year follow‐up (p = 0.0345 and p = 0.0301, respectively). In addition, the coexistence of high MACC1 and low NM23‐H1 expression and tumor budding was associated with short OS (p < 0.001). We suggest that the combination of reduced NM23‐H1, induced MACC1, and the presence of tumor budding are promising biomarkers for the prediction of recurrence and may aid the stratification of patients with stage II colon cancer for adjuvant chemotherapy.     

HIV‐1 impairs in vitro priming of naïve T cells and gives rise to contact‐dependent suppressor T cells

Priming of T cells in lymphoid tissues of HIV‐infected individuals occurs in the presence of HIV‐1. DC in this milieu activate T cells and disseminate HIV‐1 to newly activated T cells, the outcome of which may have serious implications in the development of optimal antiviral responses. We investigated the effects of HIV‐1 on DC–naïve T‐cell interactions using an allogeneic in vitro system. Our data demonstrate a dramatic decrease in the primary expansion of naïve T cells when cultured with HIV‐1‐exposed DC. CD4⁺ and CD8⁺ T cells showed enhanced expression of PD‐1 and TRAIL, whereas CTLA‐4 expression was observed on CD4⁺ T cells. It is worth noting that T cells primed in the presence of HIV‐1 suppressed priming of other naïve T cells in a contact‐dependent manner. We identified PD‐1, CTLA‐4, and TRAIL pathways as responsible for this suppresion, as blocking these negative molecules restored T‐cell proliferation to a higher degree. In conclusion, the presence of HIV‐1 during DC priming produced cells with inhibitory effects on T‐cell activation and proliferation, i.e. suppressor T cells, a mechanism that could contribute to the enhancement of HIV‐1 pathogenesis.