Prostate adenocarcinoma (PCa) and melanoma are paradigmatic examples of tumors that are either poorly or highly sensitive to therapies based on monoclonal antibodies directed against regulatory ...pathways in T lymphocytes i.e., immune checkpoint blockade (ICB). Yet, approximately 40% of melanoma patients are resistant or acquire resistance to ICB. What characterize the microenvironment of PCa and ICB-resistant melanoma are a scanty cytotoxic T cell infiltrate and a strong immune suppression, respectively. Here, we compare the tumor microenvironment in these two subgroups of cancer patients, focusing on some among the most represented immune checkpoint molecules: cytotoxic T lymphocyte-associated antigen-4, programmed death-1, lymphocyte activation gene-3, and T cell immunoglobulin and mucin-domain containing-3. We also report on several examples of crosstalk between cancer and immune cells that are mediated by inhibitory immune checkpoints and identify promising strategies aimed at overcoming ICB resistance both in PCa and melanoma.
MicroRNAs are single-stranded non-coding RNAs that simultaneously down-modulate the expression of multiple genes post-transcriptionally by binding to the 3'UTRs of target mRNAs. Here we used ...computational methods to predict microRNAs relevant in breast cancer progression. Specifically, we applied different microRNA target prediction algorithms to various groups of differentially expressed protein-coding genes obtained from four breast cancer datasets. Six potential candidates were identified, among them miR-223, previously described to be highly expressed in the tumor microenvironment and known to be actively transferred into breast cancer cells. To investigate the function of miR-223 in tumorigenesis and to define its molecular mechanism, we overexpressed miR-223 in breast cancer cells in a transient or stable manner. Alternatively we overexpressed miR-223 in mouse embryonic fibroblasts or HEK293 cells and used their conditioned medium to treat tumor cells. With both approaches, we obtained elevated levels of miR-223 in tumor cells and observed decreased migration, increased cell death in anoikis conditions and augmented sensitivity to chemotherapy but no effect on adhesion and proliferation. The analysis of miR-223 predicted targets revealed enrichment in cell death and survival-related genes and in pathways frequently altered in breast cancer. Among these genes, we showed that protein levels for STAT5A, ITGA3 and NRAS were modulated by miR-223. In addition, we proved that STAT5A is a direct miR-223 target and highlighted a possible correlation between miR-223 and STAT5A in migration and chemotherapy response. Our investigation revealed that a computational analysis of cancer gene expression datasets can be a relevant tool to identify microRNAs involved in cancer progression and that miR-223 has a prominent role in breast malignancy that could potentially be exploited therapeutically.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Highlights • Monoclonal antibodies directed against regulatory pathways in T lymphocytes are revolutionizing medical oncology. • Patients affected by melanoma, Hodgkin’s lymphoma, Merkel cell ...carcinoma, and head and neck, bladder, renal cell or non-small cell lung cancers are sensitive to immune checkpoint blockade (ICB). • Patients affected by breast, colon and prostate cancers are less sensitive to this therapeutic approach. • Several mechanisms of constitutive or acquired resistance to ICB have been identified. • Therapeutic strategies stemming from pre-clinical models can improve clinical outcomes for patients resistant to ICB.
Dendritic cells (DCs) are the most potent antigen‐presenting cells and fine‐tune the immune response. We have investigated hypoxia's effects on the differentiation and maturation of DCs from human ...monocytes in vitro, and have shown that it affects DC functions. Hypoxic immature DCs (H‐iDCs) significantly fail to capture antigens through down‐modulation of the RhoA/Ezrin‐Radixin‐Moesin pathway and the expression of CD206. Moreover, H‐iDCs released higher levels of CXCL1, VEGF, CCL20, CXCL8, and CXCL10 but decreased levels of CCL2 and CCL18, which predict a different ability to recruit neutrophils rather than monocytes and create a proinflammatory and proangiogenic environment. By contrast, hypoxia has no effect on DC maturation. Hypoxic mature DCs display a mature phenotype and activate both allogeneic and specific T cells like normoxic mDCs. This study provides the first demonstration that hypoxia inhibits antigen uptake by DCs and profoundly changes the DC chemokine expression profile and may have a critical role in DC differentiation, adaptation, and activation in inflamed tissues.
Hypoxia is a condition of low oxygen tension occurring in inflammatory tissues. Dendritic cells (DC) are professional antigen-presenting
cells whose differentiation, migration, and activities are ...intrinsically linked to the microenvironment. DCs will home and
migrate through pathologic tissues before reaching their final destination in the lymph node. We studied the differentiation
of human monocytes into immature DCs (iDCs) in a hypoxic microenvironment. We generated iDC in vitro under normoxic (iDCs) or hypoxic (Hi-DCs) conditions and examined the hypoxia-responsive element in the promoter, gene expression,
and biochemical KEGG pathways. Hi-DCs had an interesting phenotype represented by up-regulation of genes associated with cell
movement/migration. In addition, the Hi-DC cytokine/receptor pathway showed a dichotomy between down-regulated chemokines
and up-regulated chemokine receptor mRNA expression. We showed that CCR3, CX3CR1 , and CCR2 are hypoxia-inducible genes and that CCL18, CCL23, CCL26, CCL24, and CCL14 are inhibited by hypoxia. A strong chemotactic response to CCR2 and CXCR4 agonists distinguished Hi-DCs from iDCs at a functional
level. The hypoxic microenvironment promotes the differentiation of Hi-DCs, which differs from iDCs for gene expression profile
and function. The most prominent characteristic of Hi-DCs is the expression of a mobility/migratory rather than inflammatory
phenotype. We speculate that Hi-DCs have the tendency to leave the hypoxic tissue and follow the chemokine gradient toward
normoxic areas where they can mature and contribute to the inflammatory process. (Mol Cancer Res 2008;6(2):175–85)
Many patients with B-cell malignancies can be successfully treated, although tumor eradication is rarely achieved. T-cell-directed killing of tumor cells using engineered T-cells or bispecific ...antibodies is a promising approach for the treatment of hematologic malignancies.
We investigated the efficacy of CD19xCD3 DART bispecific antibody in a broad panel of human primary B-cell malignancies. The CD19xCD3 DART identified 2 distinct subsets of patients, in which the neoplastic lymphocytes were eliminated with rapid or slow kinetics. Delayed responses were always overcome by a prolonged or repeated DART exposure. Both CD4 and CD8 effector cytotoxic cells were generated, and DART-mediated killing of CD4
+
cells into cytotoxic effectors required the presence of CD8
+
cells. Serial exposures to DART led to the exponential expansion of CD4
+
and CD8
+
cells and to the sequential ablation of neoplastic cells in absence of a PD-L1-mediated exhaustion. Lastly, patient-derived neoplastic B-cells (B-Acute Lymphoblast Leukemia and Diffuse Large B Cell Lymphoma) could be proficiently eradicated in a xenograft mouse model by DART-armed cytokine induced killer (CIK) cells.
Collectively, patient tailored DART exposures can result in the effective elimination of CD19 positive leukemia and B-cell lymphoma and the association of bispecific antibodies with unmatched CIK cells represents an effective modality for the treatment of CD19 positive leukemia/lymphoma.
Langerhans cells (LC) represent a well characterized subset of dendritic cells located in the epidermis of skin and mucosae. In vivo, they originate from resident and blood-borne precursors in the ...presence of keratinocyte-derived TGFbeta. In vitro, LC can be generated from monocytes in the presence of GM-CSF, IL-4 and TGFbeta. However, the signals that induce LC during an inflammatory reaction are not fully investigated. Here we report that Activin A, a TGFbeta family member induced by pro-inflammatory cytokines and involved in skin morphogenesis and wound healing, induces the differentiation of human monocytes into LC in the absence of TGFbeta. Activin A-induced LC are Langerin+, Birbeck granules+, E-cadherin+, CLA+ and CCR6+ and possess typical APC functions. In human skin explants, intradermal injection of Activin A increased the number of CD1a+ and Langerin+ cells in both the epidermis and dermis by promoting the differentiation of resident precursor cells. High levels of Activin A were present in the upper epidermal layers and in the dermis of Lichen Planus biopsies in association with a marked infiltration of CD1a+ and Langerin+ cells. This study reports that Activin A induces the differentiation of circulating CD14+ cells into LC. Since Activin A is abundantly produced during inflammatory conditions which are also characterized by increased numbers of LC, we propose that this cytokine represents a new pathway, alternative to TGFbeta, responsible for LC differentiation during inflammatory/autoimmune conditions.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
It has recently been proposed that defective differentiation of mammary luminal progenitors predisposes to basal‐like breast cancer. However, the molecular and cellular mechanisms involved are still ...unclear. Here, we describe that the adaptor protein p130Cas is a crucial regulator of mouse mammary epithelial cell (MMEC) differentiation. Using a transgenic mouse model, we show that forced p130Cas overexpression in the luminal progenitor cell compartment results in the expansion of luminal cells, which aberrantly display basal cell features and reduced differentiation in response to lactogenic stimuli. Interestingly, MMECs overexpressing p130Cas exhibit hyperactivation of the tyrosine kinase receptor c‐Kit. In addition, we demonstrate that the constitutive c‐Kit activation alone mimics p130Cas overexpression, whereas c‐Kit downregulation is sufficient to re‐establish proper differentiation of p130Cas overexpressing cells. Overall, our data indicate that high levels of p130Cas, via abnormal c‐Kit activation, promote mammary luminal cell plasticity, thus providing the conditions for the development of basal‐like breast cancer. Consistently, p130Cas is overexpressed in human triple‐negative breast cancer, further suggesting that p130Cas upregulation may be a priming event for the onset of basal‐like breast cancer. STEM Cells2013;31:1422–1433
Tumour-infiltrating myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid cells. The main feature of MDSCs is their ability to suppress T-cell activation and function, ...which leads to immunosuppressive activity in the tumour microenvironment. Higher numbers of circulating and tumour-infiltrating MDSCs have been observed in a large number of patients with various types of tumour, and are linked to poor prognosis, especially in hormone-driven tumours. Recently, it has been demonstrated that the recruitment of MDSCs in prostate cancer confers resistance to canonical endocrine therapies, opening a new approach to the treatment of hormone-driven cancer patients.
In search of novel strategies to improve the outcome of advanced prostate cancer, we considered that prostate cancer cells rearrange iron homeostasis, favoring iron uptake and proliferation. We ...exploited this adaptation by exposing prostate cancer preclinical models to high-dose iron to induce toxicity and disrupt adaptation to androgen starvation.
We analyzed markers of cell viability and mechanisms underlying iron toxicity in androgen receptor-positive VCaP and LNCaP, castration-resistant DU-145 and PC-3, and murine TRAMP-C2 cells treated with iron and/or the antiandrogen bicalutamide. We validated the results
in VCaP and PC-3 xenografts and in TRAMP-C2 injected mice treated with iron and/or bicalutamide.
Iron was toxic for all prostate cancer cells. In particular, VCaP, LNCaP, and TRAMP-C2 were highly iron sensitive. Toxicity was mediated by oxidative stress, which primarily affected lipids, promoting ferroptosis. In highly sensitive cells, iron additionally caused protein damage. High-basal iron content and oxidative status defined high iron sensitivity. Bicalutamide-iron combination exacerbated oxidative damage and cell death, triggering protein oxidation also in poorly iron-sensitive DU-145 and PC-3 cells.
, iron reduced tumor growth in TRAMP-C2 and VCaP mice. In PC-3 xenografts, bicalutamide-iron combination caused protein oxidation and successfully impaired tumor expansion while single compounds were ineffective. Macrophages influenced body iron distribution but did not limit the iron effect on tumor expansion.
Our models allow us to dissect the direct iron effect on cancer cells. We demonstrate the proof of principle that iron toxicity inhibits prostate cancer cell proliferation, proposing a novel tool to strengthen antiandrogen treatment efficacy.
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