技术资料

Immunotherapy treatments for cancer are becoming increasingly successful,however to further improve our understanding of the T-cell recognition involved in effective responses and to encourage moves towards the development of personalised treatments for leukaemia immunotherapy,precise antigenic targets in individual patients have been identified. Cellular arrays using peptide-MHC (pMHC) tetramers allow the simultaneous detection of different antigen specific T-cell populations naturally circulating in patients and normal donors. We have developed the pMHC array to detect CD8+ T-cell populations in leukaemia patients that recognise epitopes within viral antigens (cytomegalovirus (CMV) and influenza (Flu)) and leukaemia antigens (including Per Arnt Sim domain 1 (PASD1),MelanA,Wilms' Tumour (WT1) and tyrosinase). We show that the pMHC array is at least as sensitive as flow cytometry and has the potential to rapidly identify more than 40 specific T-cell populations in a small sample of T-cells (0.8-1.4 x 10(6)). Fourteen of the twenty-six acute myeloid leukaemia (AML) patients analysed had T cells that recognised tumour antigen epitopes,and eight of these recognised PASD1 epitopes. Other tumour epitopes recognised were MelanA (n = 3),tyrosinase (n = 3) and WT1(126-134) (n = 1). One of the seven acute lymphocytic leukaemia (ALL) patients analysed had T cells that recognised the MUC1(950-958) epitope. In the future the pMHC array may be used provide point of care T-cell analyses,predict patient response to conventional therapy and direct personalised immunotherapy for patients. View Publication

Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor and is currently divided into four subtypes based on different genomic alterations,gene expression profiles and response to treatment: WNT,Sonic Hedgehog (SHH),Group 3 and Group 4. This extensive heterogeneity has made it difficult to assess the functional relevance of genes to malignant progression. For example,expression of the transcription factor Orthodenticle homeobox2 (OTX2) is frequently dysregulated in multiple MB variants; however,its role may be subtype specific. We recently demonstrated that neural precursors derived from transformed human embryonic stem cells (trans-hENs),but not their normal counterparts (hENs),resemble Groups 3 and 4 MB in vitro and in vivo. Here,we tested the utility of this model system as a means of dissecting the role of OTX2 in MB using gain- and loss-of-function studies in hENs and trans-hENs,respectively. Parallel experiments with MB cells revealed that OTX2 exerts inhibitory effects on hEN and SHH MB cells by regulating growth,self-renewal and migration in vitro and tumor growth in vivo. This was accompanied by decreased expression of pluripotent genes,such as SOX2,and was supported by overexpression of SOX2 in OTX2+ SHH MB and hENs that resulted in significant rescue of self-renewal and cell migration. By contrast,OTX2 is oncogenic and promotes self-renewal of trans-hENs and Groups 3 and 4 MB independent of pluripotent gene expression. Our results demonstrate a novel role for OTX2 in self-renewal and migration of hENs and MB cells and reveal a cell-context-dependent link between OTX2 and pluripotent genes. Our study underscores the value of human embryonic stem cell derivatives as alternatives to cell lines and heterogeneous patient samples for investigating the contribution of key developmental regulators to MB progression. View Publication

Summary The cytokine TWEAK and its cognate receptor Fn14 are members of the TNF/TNFR superfamily and are upregulated in tumors. We found that Fn14,when expressed in tumors,causes cachexia and that antibodies against Fn14 dramatically extended lifespan by inhibiting tumor-induced weight loss although having only moderate inhibitory effects on tumor growth. Anti-Fn14 antibodies prevented tumor-induced inflammation and loss of fat and muscle mass. Fn14 signaling in the tumor,rather than host,is responsible for inducing this cachexia because tumors in Fn14- and TWEAK-deficient hosts developed cachexia that was comparable to that of wild-type mice. These results extend the role of Fn14 in wound repair and muscle development to involvement in the etiology of cachexia and indicate that Fn14 antibodies may be a promising approach to treat cachexia,thereby extending lifespan and improving quality of life for cancer patients. View Publication

Acute lymphoblastic leukemia (ALL) still frequently recurs after hematopoietic stem cell transplantation (HSCT),underscoring the need to improve the graft-versus-leukemia (GvL) effect. Natural killer (NK) cells reconstitute in the first months following HSCT when leukemia burden is at its lowest,but ALL cells have been shown to be resistant to NK cell-mediated killing. We show here that this resistance is overcome by NK cell stimulation with TLR-9-activated plasmacytoid dendritic cells (pDCs). NK cell priming with activated pDCs resulted in TRAIL and CD69 up-regulation on NK cells and IFN-γ production. NK cell activation was dependent on IFN-α produced by pDCs,but was not reproduced by IFN-α alone. ALL killing was further enhanced by inhibition of KIR engagement. We showed that ALL lysis was mainly mediated by TRAIL engagement,while the release of cytolytic granules was involved when ALL expressed NK cell activating receptor ligands. Finally,adoptive transfers of activated-pDCs in ALL-bearing humanized mice delayed the leukemia onset and cure 30% of mice. Our data therefore demonstrate that TLR-9 activated pDCs are a powerful tool to overcome ALL resistance to NK cell-mediated killing and to reinforce the GvL effect of HSCT. These results open new therapeutic avenues to prevent relapse in children with ALL. View Publication

PURPOSE We conducted an open-label,single-arm Phase I/II clinical trial in metastatic CRPC (mCRPC) patients eligible for docetaxel combined with treatment with autologous mature dendritic cells (DCs) pulsed with killed LNCaP prostate cancer cells (DCVAC/PCa). The primary and secondary endpoints were safety and immune responses,respectively. Overall survival (OS),followed as a part of the safety evaluation,was compared to the predicted OS according to the Halabi and MSKCC nomograms. EXPERIMENTAL DESIGN Twenty-five patients with progressive mCRPC were enrolled. Treatment comprised of initial 7 days administration of metronomic cyclophosphamide 50 mg p.o. DCVAC/PCa treatment consisted of a median twelve doses of 1 × 107 dendritic cells per dose injected s.c. (Aldara creme was applied at the site of injection) during a one-year period. The initial 2 doses of DCVAC/PCa were administered at a 2-week interval,followed by the administration of docetaxel (75 mg/m2) and prednisone (5 mg twice daily) given every 3 weeks until toxicity or intolerance was observed. The DCVAC/PCa was then injected every 6 weeks up to the maximum number of doses manufactured from one leukapheresis. RESULTS No serious DCVAC/PCa-related adverse events have been reported. The median OS was 19 months,whereas the predicted median OS was 11.8 months with the Halabi nomogram and 13 months with the MSKCC nomogram. Kaplan-Meier analyses showed that patients had a lower risk of death compared with both MSKCC (Hazard Ratio 0.26,95% CI: 0.13-0.51) and Halabi (Hazard Ratio 0.33,95% CI: 0.17-0.63) predictions. We observed a significant decrease in Tregs in the peripheral blood. The long-term administration of DCVAC/PCa led to the induction and maintenance of PSA specific T cells. We did not identify any immunological parameter that significantly correlated with better OS. CONCLUSIONS In patients with mCRPC,the combined chemoimmunotherapy with DCVAC/PCa and docetaxel was safe and resulted in longer than expected survival. Concomitant chemotherapy did not preclude the induction of specific anti-tumor cytotoxic T cells. View Publication

Daratumumab is an anti-CD38 monoclonal antibody with lytic activity against multiple myeloma (MM) cells,including ADCC (antibody-dependent cellular cytotoxicity) and CDC (complement-dependent cytotoxicity). Owing to a marked heterogeneity of response to daratumumab therapy in MM,we investigated determinants of the sensitivity of MM cells toward daratumumab-mediated ADCC and CDC. In bone marrow samples from 144 MM patients,we observed no difference in daratumumab-mediated lysis between newly diagnosed or relapsed/refractory patients. However,we discovered,next to an expected effect of effector (natural killer cells/monocytes) to target (MM cells) ratio on ADCC,a significant association between CD38 expression and daratumumab-mediated ADCC (127 patients),as well as CDC (56 patients). Similarly,experiments with isogenic MM cell lines expressing different levels of CD38 revealed that the level of CD38 expression is an important determinant of daratumumab-mediated ADCC and CDC. Importantly,all-trans retinoic acid (ATRA) increased CD38 expression levels but also reduced expression of the complement-inhibitory proteins CD55 and CD59 in both cell lines and primary MM samples. This resulted in a significant enhancement of the activity of daratumumab in vitro and in a humanized MM mouse model as well. Our results provide the preclinical rationale for further evaluation of daratumumab combined with ATRA in MM patients. View Publication

BACKGROUND Accumulating evidence suggests that some long noncoding RNAs (lncRNAs) are involved in certain diseases,such as cancer. The lncRNA,CCDC26,is related to childhood acute myeloid leukemia (AML) because its copy number is altered in AML patients. RESULTS We found that CCDC26 transcripts were abundant in the nuclear fraction of K562 human myeloid leukemia cells. To examine the function of CCDC26,gene knockdown (KD) was performed using short hairpin RNAs (shRNAs),and four KD clones,in which CCDC26 expression was suppressed to 1% of its normal level,were isolated. This down-regulation included suppression of CCDC26 intron-containing transcripts (the CCDC26 precursor mRNA),indicating that transcriptional gene suppression (TGS),not post-transcriptional suppression,was occurring. The shRNA targeting one of the two CCDC26 splice variants also suppressed the other splice variant,which is further evidence for TGS. Growth rates of KD clones were reduced compared with non-KD control cells in media containing normal or high serum concentrations. In contrast,enhanced growth rates in media containing much lower serum concentrations and increased survival periods after serum withdrawal were observed for KD clones. DNA microarray and quantitative polymerase chain reaction screening for differentially expressed genes between KD clones and non-KD control cells revealed significant up-regulation of the tyrosine kinase receptor,KIT,hyperactive mutations of which are often found in AML. Treatment of KD clones with ISCK03,a KIT-specific inhibitor,eliminated the increased survival of KD clones in the absence of serum. CONCLUSIONS We suggest that CCDC26 controls growth of myeloid leukemia cells through regulation of KIT expression. A KIT inhibitor might be an effective treatment against the forms of AML in which CCDC26 is altered. View Publication

BACKGROUND Acute myeloid leukemia (AML) is initiated and maintained by a subset of self-renewing leukemia stem cells (LSCs),which contribute to the progression,recurrence and therapeutic resistance of leukemia. However,the mechanisms underlying the maintenance of LSCs drug resistance have not been fully defined. In this study,we attempted to elucidate the mechanisms of LSCs drug resistance. METHODS We performed reverse phase protein arrays to analyze the expression of anti-apoptotic proteins in the LSC-enriched leukemia cell line KG-1a. Immuno-blotting,cell viability and clinical AML samples were evaluated to verify the micro-assay results. The characteristics and transcriptional regulation of survivin were analyzed with the relative luciferase reporter assay,mutant constructs,chromatin immuno-precipitation (ChIP),quantitative real-time reverse transcription polymerase chain reaction (RT-qPCR),and western blotting. The levels of Sp1,c-Myc,phospho-extracellular signal-regulated kinase (p-ERK),phospho-mitogen and stress-activated protein kinase (p-MSK) were investigated in paired CD34+ and CD34- AML patient samples. RESULTS Survivin was highly over-expressed in CD34 + CD38- KG-1a cells and paired CD34+ AML patients compared with their differentiated counterparts. Functionally,survivin contributes to the drug resistance of LSCs,and Sp1 and c-Myc concurrently regulate levels of survivin transcription. Clinically,Sp1 and c-Myc were significantly up-regulated and positively correlated with survivin in CD34+ AML patients. Moreover,Sp1 and c-Myc were further activated by the ERK/MSK mitogen-activated protein kinase (MAPK) signaling pathway,modulating survivin levels. CONCLUSION Our findings demonstrated that ERK/MSK/Sp1/c-Myc axis functioned as a critical regulator of survivin expression in LSCs,offering a potential new therapeutic strategy for LSCs therapy. View Publication

BACKGROUND In colorectal carcinoma (CRC),activation of the Raf/MEK/ERK signaling pathway is commonly observed. In addition,the commonly used 5FU-based chemotherapy in patients with metastatic CRC was found to enrich a subpopulation of CD26(+) cancer stem cells (CSCs). As activation of the Raf/MEK/ERK signaling pathway was also found in the CD26(+) CSCs and therefore,we hypothesized that an ATP-competitive pan-Raf inhibitor,Raf265,is effective in eliminating the cancer cells and the CD26(+) CSCs in CRC patients. METHODS HT29 and HCT116 cells were treated with various concentrations of Raf265 to study the anti-proliferative and apoptotic effects of Raf265. Anti-tumor effect was also demonstrated using a xenograft model. Cells were also treated with Raf265 in combination with 5FU to demonstrate the anti-migratory and invasive effects by targeting on the CD26(+) CSCs and the anti-metastatic effect of the combined treatment was shown in an orthotopic CRC model. RESULTS Raf265 was found to be highly effective in inhibiting cell proliferation and tumor growth through the inhibition of the RAF/MEK/ERK signaling pathway. In addition,anti-migratory and invasive effect was found with Raf265 treatment in combination with 5FU by targeting on the CD26(+) cells. Finally,the anti-tumor and anti-metastatic effect of Raf265 in combination with 5FU was also demonstrated. CONCLUSIONS This preclinical study demonstrates the anti-tumor and anti-metastatic activity of Raf265 in CRC,providing the basis for exploiting its potential use and combination therapy with 5FU in the clinical treatment of CRC. View Publication

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are responsive to EGFR-tyrosine kinase inhibitor (EGFR-TKI). However,NSCLC patients with secondary somatic EGFR mutations are resistant to EGFR-TKI treatment. In this study,we investigated the effect of TG101348 (a JAK2 inhibitor) on the tumor growth of erlotinib-resistant NSCLC cells. Cell proliferation,apoptosis,gene expression and tumor growth were evaluated by diphenyltetrazolium bromide (MTT) assay,flow cytometry,terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining,Western Blot and a xenograft mouse model,respectively. Results showed that erlotinib had a stronger impact on the induction of apoptosis in erlotinib-sensitive PC-9 cells but had a weaker effect on erlotinib-resistant H1975 and H1650 cells than TG101348. TG101348 significantly enhanced the cytotoxicity of erlotinib to erlotinib-resistant NSCLC cells,stimulated erlotinib-induced apoptosis and downregulated the expressions of EGFR,p-EGFR,p-STAT3,Bcl-xL and survivin in erlotinib-resistant NSCLC cells. Moreover,the combined treatment of TG101348 and erlotinib induced apoptosis,inhibited the activation of p-EGFR and p-STAT3,and inhibited tumor growth of erlotinib-resistant NSCLC cells in vivo. Our results indicate that TG101348 is a potential adjuvant for NSCLC patients during erlotinib treatment. View Publication

TOX is a nuclear factor essential for the development of CD4(+) T cells in the thymus. It is normally expressed in low amounts in mature CD4(+) T cells of the skin and the peripheral blood. We have recently discovered that the transcript levels of TOX were significantly increased in mycosis fungoides,the most common type of cutaneous T-cell lymphoma (CTCL),as compared to normal skin or benign inflammatory dermatoses. However,its involvement in advanced CTCL and its biological effects on CTCL pathogenesis have not been explored. In this study,we demonstrate that TOX expression is also enhanced significantly in primary CD4(+)CD7(-) cells from patients with Sézary syndrome,a leukemic variant of CTCL,and that high TOX transcript levels correlate with increased disease-specific mortality. Stable knockdown of TOX in CTCL cells promoted apoptosis and reduced cell cycle progression,leading to less cell viability and colony-forming ability in vitro and to reduced tumor growth in vivo. Furthermore,TOX knockdown significantly increased 2 cyclin-dependent kinase (CDK) inhibitors,CDKN1B and CDKN1C. Lastly,blocking CDKN1B and CDKN1C reversed growth inhibition of TOX knockdown. Collectively,these findings provide strong evidence that aberrant TOX activation is a critical oncogenic event for CTCL. View Publication

Mesenchymal stem or stromal cells (MSCs) have many potential therapeutic applications including therapies for cancers and tissue damages caused by cancers or radical cancer treatments. However,tissue-derived MSCs such as bone marrow MSCs (BM-MSCs) may promote cancer progression and have considerable donor variations and limited expandability. These issues hinder the potential applications of MSCs,especially those in cancer patients. To circumvent these issues,we derived MSCs from transgene-free human induced pluripotent stem cells (iPSCs) efficiently with a modified protocol that eliminated the need of flow cytometric sorting. Our iPSC-derived MSCs were readily expandable,but still underwent senescence after prolonged culture and did not form teratomas. These iPSC-derived MSCs homed to cancers with efficiencies similar to BM-MSCs but were much less prone than BM-MSCs to promote the epithelial-mesenchymal transition,invasion,stemness,and growth of cancer cells. The observations were probably explained by the much lower expression of receptors for interleukin-1 and TGFβ,downstream protumor factors,and hyaluronan and its cofactor TSG6,which all contribute to the protumor effects of BM-MSCs. The data suggest that iPSC-derived MSCs prepared with the modified protocol are a safer and better alternative to BM-MSCs for therapeutic applications in cancer patients. The protocol is scalable and can be used to prepare the large number of cells required for off-the-shelf" therapies and bioengineering applications." View Publication