Search

SummaryBecause Tissue-Resident Memory T (TRM) cells contribute critically to body-surface immunoprotection and/or immunopathology in multiple settings, their regulation is biologically and clinically important. Interestingly, TRMcommonly develop in epithelia part-shaped by innate-like lymphocytes that become tissue-intrinsic during development. Here we show that polyclonal TRMcells induced by allergic contact dermatitis (ACD) interact with signature intraepidermal γδ T cells, facilitating a feedback-loop wherein TRM-derived IFNγ upregulates PD-L1 on γδ cells that can thereupon regulate PD1+TRM. Thus, TRMinduced by ACD in mice lacking either local γδ cells, or lacking a single gene (IFNγR) expressed by local γδ cells, displayed enhanced proliferative and effector potentials. Those phenotypes were associated with strikingly limited motility, reduced TRMquality. and an impaired capacity to restrain melanoma. Thus, inter-individual and tissue-specific variation in how tissue-intrinsic lymphocytes integrate with TRMmay sit upstream of variation in responses to cancer, allergens and other challenges, and may likewise underpin inflammatory pathologies repeatedly observed in γδ-deficient animals.

Increasing evidence indicates that cancer cell stress induced by chemotherapeutic agents promote antitumor immune responses and contribute to their full clinical efficacy. In this article, we identify the signaling events underlying chemotherapy-induced NKG2D and DNAM-1 ligand expression on multiple myeloma (MM) cells. Our findings indicate that sublethal doses of doxorubicin and melphalan initiate a DNA damage response (DDR) controlling ligand upregulation on MM cell lines and patient-derived malignant plasma cells in Chk1/2-dependent and p53-independent manner. Drug-induced MICA and PVR gene expression are transcriptionally regulated and involve DDR-dependent E2F1 transcription factor activity. We also describe the involvement of changes in the redox state in the control of DDR-dependent upregulation of ligand surface expression and gene transcriptional activity by using the antioxidant agent N-acetyl-l-cysteine. Finally, in accordance with much evidence indicating that DDR and oxidative stress are major determinants of cellular senescence, we found that redox-dependent DDR activation upon chemotherapeutic treatment is critical for MM cell entry in premature senescence and is required for the preferential ligand upregulation on senescent cells, which are preferentially killed by NK cells and trigger potent IFN-γ production. We propose immunogenic senescence as a mechanism that promotes the clearance of drug-treated tumor cells by innate effector lymphocytes, including NK cells.

CD127 is the IL-7 receptor α-chain and its expression is tightly regulated during T-cell differentiation. We previously showed that the bone marrow (BM) is a key organ for proliferation and maintenance of both antigen-specific and CD44(high) memory CD8(+) T cells. Interestingly, BM memory CD8(+) T cells express lower levels of membrane CD127 than do the corresponding spleen and lymph node cells. We investigated the requirements for CD127 downmodulation by CD44(high) memory-phenotype CD8(+) T cells in the BM of C57BL/6 mice. By comparing genetically modified (i.e. CD127tg, IL-7 KO, IL-15 KO, IL-15Rα KO) with wild-type (WT) mice, we found that the key molecule regulating CD127 downmodulation was IL-15 but not IL-7, and that the intact CD127 gene was required, including the promoter. Indeed, CD127 mRNA transcript levels were lower in CD44(high) CD8(+) T cells from the BM than in those from the spleen of WT mice, indicating organ-specific regulation. Although levels of the CD127 transactivator Foxo1 were low in BM CD44(high) CD8(+) T cells, Foxo1 was not involved in IL-15-induced CD127 downmodulation. Thus, recirculating CD44(high) CD8(+) T cells passing through the BM transiently downregulate CD127 in response to IL-15, with implications for human therapies acting on the IL-7/CD127 axis, for example cytokine treatments in cancer patients.

There is much evidence to support a role for natural killer (NK) cells in controlling the progression of multiple myeloma (MM), a malignancy characterized by an abnormal plasma cell proliferation in the bone marrow (BM). Induction of DNA damage response has been recently shown capable of enhancing NKG2D ligand (NKG2DL) expression, but nothing is known about DNAM-1 ligand (DNAM-1L) regulation. In this study, we show that myeloma cells treated with low doses of therapeutic agents commonly used in the management of patients with MM, such as doxorubicin, melphalan, and bortezomib, up-regulate DNAM-1 and NKG2D ligands. Accordingly, therapeutic drug treatment of MM cells increases NK-cell degranulation, the NKG2D and DNAM-1 receptors being the major triggering molecules. Similar data were also obtained using ex vivo primary plasma cells derived from MM patients. Drug-induced DNAM-1 and NKG2D ligand expression was abolished after treatment with the ATM (ataxia telangiectasia mutated) and ATR (ATM- and RAD3-related) pharmacologic inhibitors caffeine and KU-55933, and was preferentially associated with senescent cells arrested in the G2 phase of the cell cycle. Altogether, our findings have identified a common pathway that can trigger the up-regulation of different NK cell–activating ligands and suggest that NK cells represent an immunosurveillance mechanism toward cells undergoing stress-induced senescent programs.

International audience; Malignant cells constitutively express Natural killer group 2, member D (NKG2D) or DNAX Accessory Molecule-1 (DNAM-1) ligands, yet they are often unable to trigger a robust cytotoxic cell response. It may be therapeutically useful to implement strategies aimed at increasing the density of NKG2D and DNAM-1 ligands on the surface of cancer cells, endowing them with the capacity to activate potent antitumor natural killer-cell responses.

Engagement of NKG2D and DNAX accessory molecule-1 (DNAM-1) receptors on lymphocytes plays an important role for anticancer response and represents an interesting therapeutic target for pharmacological modulation. In this study, we investigated the effect of inhibitors targeting the glycogen synthase kinase-3 (GSK3) on the expression of NKG2D and DNAM-1 ligands in multiple myeloma (MM) cells. GSK3 is a pleiotropic serine–threonine kinase point of convergence of numerous cell-signaling pathways, able to regulate the proliferation and survival of cancer cells, including MM. We found that inhibition of GSK3 upregulates both MICA protein surface and mRNA expression in MM cells, with little or no effects on the basal expression of the MICB and DNAM-1 ligand poliovirus receptor/CD155. Moreover, exposure to GSK3 inhibitors renders myeloma cells more efficient to activate NK cell degranulation and to enhance the ability of myeloma cells to trigger NK cell–mediated cytotoxicity. We could exclude that increased expression of β-catenin or activation of the heat shock factor-1 (transcription factors inhibited by active GSK3) is involved in the upregulation of MICA expression, by using RNA interference or viral transduction of constitutive active forms. On the contrary, inhibition of GSK3 correlated with a downregulation of STAT3 activation, a negative regulator of MICA transcription. Both Tyr705 phosphorylation and binding of STAT3 on MICA promoter are reduced by GSK3 inhibitors; in addition, overexpression of a constitutively active form of STAT3 significantly inhibits MICA upregulation. Thus, we provide evidence that regulation of the NKG2D-ligand MICA expression may represent an additional immune-mediated mechanism supporting the antimyeloma activity of GSK3 inhibitors.

New arylthioindole derivatives having different cyclic substituents at position 2 of the indole were synthesized as anticancer agents. Several compounds inhibited tubulin polymerization at submicromolar concentration and inhibited cell growth at low nanomolar concentrations. Compounds 18 and 57 were superior to the previously synthesized 5. Compound 18 was exceptionally potent as an inhibitor of cell growth: it showed IC50 = 1.0 nM in MCF-7 cells, and it was uniformly active in the whole panel of cancer cells and superior to colchicine and combretastatin A-4. Compounds 18, 20, 55, and 57 were notably more potent than vinorelbine, vinblastine, and paclitaxel in the NCI/ADR-RES and Messa/Dx5 cell lines, which overexpress P-glycoprotein. Compounds 18 and 57 showed initial vascular disrupting effects in a tumor model of liver rhabdomyosarcomas at 15 mg/kg intravenous dosage. Derivative 18 showed water solubility and higher metabolic stability than 5 in human liver microsomes.

New arylthioindoles (ATIs) were obtained by replacing the 2-alkoxycarbonyl group with a bioisosteric 5-membered heterocycle nucleus. The new ATIs 5, 8, and 10 inhibited tubulin polymerization, reduced cell growth of a panel of human transformed cell lines, and showed higher metabolic stability than the reference ester 3. These compounds induced mitotic arrest and apoptosis at a similar level as combretastatin A-4 and vinblastine and triggered caspase-3 expression in a significant fraction of cells in both p53-proficient and p53-defective cell lines. Importantly, ATIs 5, 8, and 10 were more effective than vinorelbine, vinblastine, and paclitaxel as growth inhibitors of the P-glycoprotein-overexpressing cell line NCI/ADR-RES. Compound 5 was shown to have medium metabolic stability in both human and mouse liver microsomes, in contrast to the rapidly degraded reference ester 3, and a pharmacokinetic profile in the mouse characterized by a low systemic clearance and excellent oral bioavailability.

Modulation of the host immune system represents a promising therapeutic approach against cancer, including multiple myeloma. Recent findings indicate that the NK group 2D (NKG2D)- and DNAX accessory molecule-1 (DNAM-1)-activating receptors play a prominent role in tumor recognition and elimination by cytotoxic lymphocytes, suggesting that the levels of NKG2D and DNAM-1 ligand expression on tumor cells may be a critical factor to improve the immune response against cancer. In this study, we tested the effect of 17-allylaminogeldanamycin and radicicol, drugs targeting the heat shock protein-90 (HSP-90) chaperone protein and displaying antimyeloma activity, on the expression of NKG2D and DNAM-1 ligands in human myeloma cell lines. We demonstrate that HSP-90 inhibitors are able to up-regulate both MHC class I chain-related (MIC) A and MICB protein surface and mRNA expression in human myeloma cell lines, without any significant effect on the basal expression of the DNAM-1 ligand poliovirus receptor CD155, or induction of nectin-2 and UL16-binding proteins. Activation of the transcription factor heat shock factor-1 by HSP-90 inhibitors is essential for the up-regulation of MICA/MICB expression and knockdown of heat shock factor-1 using small hairpin RNA interference blocks this effect. Moreover, in vitro and in vivo binding of heat shock factor-1 to MICA and MICB promoters indicates that it may enhance NKG2D ligand expression at the transcriptional level. Finally, exposure to HSP-90 inhibitors renders myeloma cells more efficient to activate NK cell degranulation and a blocking Ab specific for NKG2D significantly reduces this effect. Thus, these results provide evidence that targeting NKG2D ligands expression may be an additional mechanism supporting the antimyeloma activity of HSP-90 inhibitors and suggest their possible immunotherapeutic value.

e22097 Background: Prostate cancer (PCa) remains a significant health burden. There is evidence that PCa development is substantially controlled by the immune system. The body harbours a natural me...

11081 Background: γδ T cells have attracted interest as a biological tool for cancer therapy owing to demonstrated tumour cytocidal potential in vitro, and their correlation with improved outcome i...

There are currently no reports concerning the role of the transporter breast cancer resistance protein (BCRP) in adult acute lymphoblastic leukemia (ALL). The aim of this study was to evaluate the frequency of BCRP expression, its correlation with other MDR-related proteins and their prognostic role in 118 untreated adult ALL patients uniformly treated according to the GIMEMA protocol LAL2000. BCRP protein expression was detected by flow cytometry using the MoAb BXP-34 (Kamiya, WA); results were analyzed according to the KS statistic test (D-value). Detection of BCRP in the cell lines MCF7pcDNA3 and MDA231pcDNA3 showed a D-value of 0.12±0.11 and 0.09±0.06, respectively. In contrast, the cell lines MCF7pcDNA3clone 8 and MDA231pcDNA3clone23 that overexpress BCRP were characterized by a D-value of 0.44±0.21 and 0.33±0.11, respectively. Analysis of primary ALL samples showed a BCRP expression (D-value≥ 0.20) in 86/118 (72.9%) cases, with a mean value of 0.36±0.22 (range 0.00–0.87, median 0.37) in the overall population. BCRP expression resulted associated with age (P=0.054). No significant difference was found with other clinical characteristics. The multidrug resistance associated protein (MRP1) (MoAb MRPm6) resulted expressed in 70.1% of samples (D-value≥ 0.20); the MDR1/Pglycoprotein-170 (MDR1) (MoAb MRK16) was present in 28.2% of cases (D-value≥ 0.05). Samples analyzed for both BCRP and MRP1 expression (115/118) showed a significant correlation (R=0.56; P=0.0001): 15.6% of cases were negative for both proteins, while 61.7% expressed both BCRP and MRP1. BCRP expression did not correlate with MDR1 expression. None of these proteins separately influenced the achievement of complete remission (CR). In contrast, BCRP/MRP1 co-expression was associated (P=0.091) with failure to respond to induction treatment: 31% (18/58) of BCRP+/MRP1+ patients failed to achieve CR, while 84.2% (32/38) of cases negative for only one protein or for both responded to induction treatment. Kaplan-Meier analysis was then performed for event-free survival (EFS): among 99 evaluable patients a significant difference (P=0.03) was observed with a median EFS of 8.4 months (95%CI, 5.63–11.28) in BCRP+ cases (72) compared to BCRP- patients (27) for whom median EFS has not been achieved. Multivariate analysis confirmed the unfavorable prognostic role of BCRP positive cases on EFS (P=0.072;OR1.87, 95% CI, 0.94–3.70). In summary, our study shows that adult ALL frequently express BCRP. In patients treated with the GIMEMA LAL 2000 protocol EFS was unfavorably affected by BCRP expression, while co-expression of MRP1 and BCRP was associated with failure to induction treatment. The expression of these proteins may contribute to explain the overall poor outcome of adult ALL patients, suggesting that therapeutic strategies based on overcoming drug resistance remain an important goal to be pursued.

Summary Many body surfaces harbor organ-specific γδ T cell compartments that contribute to tissue integrity. Thus, murine dendritic epidermal T cells (DETCs) uniquely expressing T cell receptor (TCR)-Vγ5 chains protect from cutaneous carcinogens. The DETC repertoire is shaped by Skint1, a butyrophilin-like (Btnl) gene expressed specifically by thymic epithelial cells and suprabasal keratinocytes. However, the generality of this mechanism has remained opaque, since neither Skint1 nor DETCs are evolutionarily conserved. Here, Btnl1 expressed by murine enterocytes is shown to shape the local TCR-Vγ7+ γδ compartment. Uninfluenced by microbial or food antigens, this activity evokes the developmental selection of TCRαβ+ repertoires. Indeed, Btnl1 and Btnl6 jointly induce TCR-dependent responses specifically in intestinal Vγ7+ cells. Likewise, human gut epithelial cells express BTNL3 and BTNL8 that jointly induce selective TCR-dependent responses of human colonic Vγ4+ cells. Hence, a conserved mechanism emerges whereby epithelia use organ-specific BTNL/Btnl genes to shape local T cell compartments., Graphical Abstract Image 1, Highlights • Gut epithelial butyrophilin-like 1 (Btnl1) shapes the local γδ T cell compartment • Other organ-specific epithelial Btnl genes select cognate γδ cells in other sites • Btnl heteromers can specifically activate γδ T cells with cognate T cell receptors • Human BTNL genes reveal a conserved biology of epithelial T cell regulation, Epithelial cells provide signals that instruct the development and function of their local γδ T cell compartments so that these immune cells can support the non-immune functions of the different barrier tissues.