Explore the vast range of titles available.

Immunotherapy has raised high expectations in the treatment of virtually every cancer. Many current efforts are focused on ensuring the efficient delivery of active cytotoxic cells to tumors. It is assumed that, once these active cytotoxic cells are correctly engaged to cancer cells, they will unfailingly eliminate the latter, provided that inhibitory factors are in check. T cell bispecific antibodies (TCBs) and chimeric antigen receptors (CARs) offer an opportunity to test this assumption. Using TCB and CARs directed against HER2, here we show that disruption of interferon-gamma signaling confers resistance to killing by active T lymphocytes. The kinase JAK2, which transduces the signal initiated by interferon-gamma, is a component repeatedly disrupted in several independently generated resistant models. Our results unveil a seemingly widespread strategy used by cancer cells to resist clearance by redirected lymphocytes. In addition, they open the possibility that long-term inhibition of interferon-gamma signaling may impair the elimination phase of immunoediting and, thus, promote tumor progression. Several mechanisms of resistance to T cell-engaging therapies have been described for solid tumors. Here, by using T cell bispecific antibodies and chimeric antigen receptors (CAR) T cells targeting HER2, the authors show that cancer cell intrinsic disruption of interferon-gamma signalling, including downregulation of JAK2, confers resistance to T-cell mediated cytotoxicity.

The redirection of T lymphocytes against tumor-associated or tumor-specific antigens, using bispecific antibodies or chimeric antigen receptors (CAR), has shown therapeutic success against certain hematological malignancies. However, this strategy has not been effective against solid tumors. Here, we describe the development of CAR T cells targeting p95HER2, a tumor-specific antigen found in HER2-amplified solid tumors. These CAR T cells display robust activity against p95HER2-expressing cell lines but demonstrate limited efficacy against patient-derived xenografts. As p95HER2 is invariably detectable on tumor cells that overexpress HER2, but not those that express HER2 at normal levels, we arm p95HER2-specific CAR T cells with affinity-tuned bispecific antibodies against HER2 and CD3 in order to redirect them only to HER2-amplified cells. The combination of p95HER2.CAR T cells and HER2 x CD3 bispecific antibodies lead to a complete regression in three HER2-positive, patient-derived mouse xenografts tumor models. This combination represents a promising strategy to redirect T cells against a subset of HER2-positive tumors. Chimeric antigen receptor T (CAR-T) cell therapy is efficient in certain haematologic malignancies, but clinical success in solid tumours has been hampered by scarcity of tumour-specific antigens. Here authors show that combination therapy using CAR T cells targeting p95HER2 and bispecific antibodies against HER2 and CD3 consistently leads to complete regression in HER2-positive, patient-derived xenografts tumours in mouse models.

Ligand-dependent corepressor (LCOR) mediates normal and malignant breast stem cell differentiation. Cancer stem cells (CSCs) generate phenotypic heterogeneity and drive therapy resistance, yet their role in immunotherapy is poorly understood. Here we show that immune-checkpoint blockade (ICB) therapy selects for LCOR low CSCs with reduced antigen processing/presentation machinery (APM) driving immune escape and ICB resistance in triple-negative breast cancer (TNBC). We unveil an unexpected function of LCOR as a master transcriptional activator of APM genes binding to IFN-stimulated response elements (ISREs) in an IFN signaling-independent manner. Through genetic modification of LCOR expression, we demonstrate its central role in modulation of tumor immunogenicity and ICB responsiveness. In TNBC, LCOR associates with ICB clinical response. Importantly, extracellular vesicle (EV) Lcor– messenger RNA therapy in combination with anti-PD-L1 overcame resistance and eradicated breast cancer metastasis in preclinical models. Collectively, these data support LCOR as a promising target for enhancement of ICB efficacy in TNBC, by boosting of tumor APM independently of IFN. Celià-Terrassa and colleagues identify LCOR-low cancer stem cells driving tumor immunity and propose LCOR induction with mRNA therapy as an enhancer of immunotherapy response.

Background Insertional mutagenesis screens of retrovirus-induced mouse tumors have proven valuable in human cancer research and for understanding adverse effects of retroviral-based gene therapies. In previous studies, the assignment of mouse genes to individual retroviral integration sites has been based on close proximity and expression patterns of annotated genes at target positions in the genome. We here employed next-generation RNA sequencing to map retroviral-mouse chimeric junctions genome-wide, and to identify local patterns of transcription activation in T-lymphomas induced by the murine leukemia gamma-retrovirus SL3-3. Moreover, to determine epigenetic integration preferences underlying long-range gene activation by retroviruses, the colocalization propensity with common epigenetic enhancer markers (H3K4Me1 and H3K27Ac) of 6,117 integrations derived from end-stage tumors of more than 2,000 mice was examined. Results We detected several novel mechanisms of retroviral insertional mutagenesis: bidirectional activation of mouse transcripts on opposite sides of a provirus including transcription of unannotated mouse sequence; sense/antisense-type activation of genes located on opposite DNA strands; tandem-type activation of distal genes that are positioned adjacently on the same DNA strand; activation of genes that are not the direct integration targets; combination-type insertional mutagenesis, in which enhancer activation, alternative chimeric splicing and retroviral promoter insertion are induced by a single retrovirus. We also show that irrespective of the distance to transcription start sites, the far majority of retroviruses in end-stage tumors colocalize with H3K4Me1 and H3K27Ac-enriched regions in murine lymphoid tissues. Conclusions We expose novel retrovirus-induced host transcription activation patterns that reach beyond a single and nearest annotated gene target. Awareness of this previously undescribed layer of complexity may prove important for elucidation of adverse effects in retroviral-based gene therapies. We also show that wild-type gamma-retroviruses are frequently positioned at enhancers, suggesting that integration into regulatory regions is specific and also subject to positive selection for sustaining long-range gene activation in end-stage tumors. Altogether, this study should prove useful for extrapolating adverse outcomes of retroviral vector therapies, and for understanding fundamental cellular regulatory principles and retroviral biology.

Redirection of T lymphocytes against tumor-associated or tumor-specific antigens, via bispecifc T cells engagers (BiTEs) or chimeric antigen receptors (CARs), is a successful therapeutic strategy against certain hematologic malignancies. In contrast, so far it has failed against solid tumors. Given the scarcity of tumor-specific antigens, the vast majority of BiTEs and CAR Ts developed to date have been directed against tumor-associated antigens. These are expressed in some normal tissues and, as a consequence, frequent and serious side effects caused by on-target off-tumor activity have limited the use of BiTEs and CARs in the clinic. P95HER2 is a fragment of the tyrosine kinase receptor HER2 expressed in more than 30% of HER2-amplified tumors. It has been previoulsy shown that p95HER2 is a tumor-specific antigen. Here we present the generation of CARs targeting p95HER2. p95HER2 CAR T cells show remarkable activity against p95HER2-expressing cells in vitro and in vivo. Further, they are also effective against lung and brain metastasis. These tumor-specific CAR T cells could be used in the near future to deliver additional anti-tumor therapies in a safe manner.

Background: Severe cases of lymphopenia have been reported during siponimod clinical trials, which may negatively impact its benefit/risk profile. Objective: We aimed to evaluate the incidence of lymphopenia following the initiation of siponimod treatment in clinical practice. The secondary objectives included the analysis of factors predisposing to and the clinical relevance of lymphopenia events. Methods: In this multicenter retrospective cohort study, information collected from the medical records of 129 patients with MS from 15 tertiary hospitals in Spain who initiated treatment with Siponimod were followed-up for at least 3 months, including at least one lymphocyte count evaluation per patient. Results: Of the 129 patients, 121 (93.6%) reported lymphopenia events, including 110 (85.3%) with grade ≤ 3 and 11 (8.5%) with grade 4 lymphopenia, higher than those reported in the pivotal clinical trial (73.3% and 3.3% for grade ≤ 3 and grade 4 lymphopenia, respectively). The study included an unexpectedly high proportion of male subjects (72.9%), which might have led to an underestimation of the actual magnitude of the risk. Conclusions: In this study, the incidence and severity of lymphopenia after starting siponimod treatment were higher than those reported in previous clinical trials. Therefore, our results reinforce the need for the closer monitoring of novel MS drugs in clinical practice, as well as larger and longer follow-up studies to properly characterize this risk.