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Among others, expression levels of programmed cell death 1 ligand 1 (PD‐L1) have been explored as biomarkers of the response to immune checkpoint inhibitors in cancer therapy. Here, we present the results of a chemical screen that interrogated how medically approved drugs influence PD‐L1 expression. As expected, corticosteroids and inhibitors of Janus kinases were among the top PD‐L1 downregulators. In addition, we identified that PD‐L1 expression is induced by antiestrogenic compounds. Transcriptomic analyses indicate that chronic estrogen receptor alpha (ERα) inhibition triggers a broad immunosuppressive program in ER‐positive breast cancer cells, which is subsequent to their growth arrest and involves the activation of multiple immune checkpoints together with the silencing of the antigen‐presenting machinery. Accordingly, estrogen‐deprived MCF7 cells are resistant to T‐cell‐mediated cell killing, in a manner that is independent of PD‐L1, but which is reverted by estradiol. Our study reveals that while antiestrogen therapies efficiently limit the growth of ER‐positive breast cancer cells, they concomitantly trigger a transcriptional program that favors their immune evasion., Under prolonged hormone therapy, ER+ breast cancer cells activate an inflammatory transcriptional program, which includes a generalized upregulation of immune checkpoint mediators together with the downregulation of the antigen‐presenting machinery. These findings reveal that, while hormone therapies efficiently arrest the growth of ER+ breast cancer cells, they also promote a phenotype switch that favors their immune evasion.

ObjectiveLiver fibrosis constitutes a major health problem worldwide due to its rapidly increasing prevalence and the lack of specific and effective treatments. Growing evidence suggests that signalling through cytokine-activated Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathways regulates liver fibrosis and regeneration. Rilpivirine (RPV) is a widely used anti-HIV drug not reported to produce hepatotoxicity. We aimed to describe the potential hepatoprotective effects of RPV in different models of chronic liver injury, focusing on JAK-STAT signalling regulation.DesignThe effects of RPV on hepatic steatosis, inflammation and fibrogenesis were studied in a nutritional mouse model of non-alcoholic fatty liver disease, carbon tetrachloride-induced fibrosis and bile duct ligation-induced fibrosis. Primary human hepatic stellate cells (hHSC) and human cell lines LX-2 and Hep3B were used to investigate the underlying molecular mechanisms.ResultsRPV exerted a clear anti-inflammatory and antifibrotic effect in all the in vivo models of liver injury employed, and enhanced STAT3-dependent proliferation in hepatocytes and apoptosis in HSC through selective STAT1 activation. These results were reproduced in vitro; RPV undermined STAT3 activation and triggered STAT1-mediated pathways and apoptosis in HSC. Interestingly, this selective pro-apoptotic effect completely disappeared when STAT1 was silenced. Conditioned medium experiments showed that HSC apoptosis activated STAT3 in hepatocytes in an interleukin-6-dependent mechanism.ConclusionRPV ameliorates liver fibrosis through selective STAT1-dependent induction of apoptosis in HSC, which exert paracrinal effects in hepatocytes, thus promoting liver regeneration. RPV’s actions may represent an effective strategy to treat chronic liver diseases of different aetiologies and help identify novel therapeutic targets.

Estrogen receptor (ER)-positive breast tumors are routinely treated with estrogen-depriving therapies. Despite their effectiveness, patients often progress into a more aggressive form of the disease. Through a chemical screen oriented to identify chemicals capable of inducing the expression of the immune-checkpoint ligand PD-L1, we found antiestrogens as hits. Subsequent validations confirmed that estrogen deprivation or ERα depletion induces PD-L1 expression in ER-positive breast cancer cells, both in vitro and in vivo. Likewise, PD-L1 expression is increased in metastasis arising from breast cancer patients receiving adjuvant hormonal therapy for their local disease. Transcriptome analyses indicate that estrogen deprivation triggers a broad immunosuppressive program, not restricted to PD-L1. Accordingly, estrogen deprived MCF7 cells are resistant to T-cell mediated cell killing, in a manner that can be reverted by estradiol. Our study reveals that while antiestrogen therapies effectively limit tumor growth in ER-positive breast cancers, they also trigger a transcriptional program that favors immune evasion.

We assessed the role of vitreoretinal interface status in the development of pseudophakic cystoid macular edema (PCME) after cataract surgery.Prospective cohort study in which 112 patients (112 eyes) scheduled for cataract surgery were selected at random to undergo spectral domain optical coherence tomography (OCT) within 1 week preoperatively and at 1 and 3 months postoperatively. Spectral domain OCT macular images included no vitreoretinal contact, focal and diffuse vitreomacular adhesion, focal and diffuse vitreomacular traction, epiretinal membrane, macular hole, and macular edema.The incidence of PCME was 11.6% (13 eyes), all of them being diagnosed at 1 month, and 7 eyes resolved at 3 months. The only risk factor for PCME was detection of nonsurgical epiretinal membrane by spectral domain OCT before phacoemulsification, being developed in 5 of 16 eyes (χ = 0.08, odds ratio 4.53, 95% confidence interval 1.28-16.13). Other variables such as posterior vitreous detachment, subfoveal choroidal thickness, diabetes, or hypertension were not significantly associated with PCME.In this cohort, preoperative detection of epiretinal membrane by spectral domain OCT was a risk factor for PCME after cataract extraction. It is recommended to perform a spectral domain OCT before cataract surgery because the presence of an epiretinal membrane may be passed unnoticed by fundus examination.

Background NRTIs are essential components of HIV therapy with well-documented, long-term mitochondrial toxicity in hepatic cells, but whose acute effects on mitochondria are unclear. As acetaminophen-induced hepatotoxicity also involves mitochondrial interference, we hypothesized that it would be exacerbated in the context of ART. Methods We evaluated the acute effects of clinically relevant concentrations of the most widely used NRTIs, alone or combined with acetaminophen, on mitochondrial function and cellular viability. Results The purine analogues abacavir and didanosine produced an immediate and concentration-dependent inhibition of oxygen consumption and complex I and III activity. This inhibition was accompanied by an undermining of mitochondrial function, with increased production of reactive oxygen species and reduction of mitochondrial membrane potential and intracellular ATP levels. However, this interference did not compromise cell survival. Co-administration with concentrations of acetaminophen below those considered hepatotoxic exacerbated the deleterious effects of both compounds on mitochondrial function and compromised cellular viability, showing a clear correlation with diminished glutathione levels. Conclusions The simultaneous presence of purine analogues and low concentrations of acetaminophen significantly potentiates mitochondrial dysfunction, increasing the risk of liver injury. This new mechanism is relevant given the liver's susceptibility to mitochondrial dysfunction-related toxicity and the tendency of the HIV infection to increase oxidative stress. This work was supported by the Instituto de Salud Carlos III, Ministerio de Economía y Competitividad [grants PI11/00327, PI13/1025, PI14/00312 and CIBER CB06/04/0071], and postgraduate research grant FI12/00198 awarded to F.A.; the Conselleria d'Educació, Formació i Ocupació, Generalitat Valenciana [grants PROMETEO/2010/060, PROMETEOII/2014/035, ACOMP/2013/236 and GVA/2014/118] and postgraduate research grant ACIF/2013/136 awarded to M.P.; the Universitat Jaume I [grant P1.1B-2014/15]; the Ministerio of Economía y Competitividad [Juan de la Cierva contract JCI-2012–15124 to A.B.-G.]; the Ministerio de Sanidad and Generalitat Valenciana [contract CES10/030 to V.M.V]; and the Ministerio de Educación, Cultura y deporte [postgraduate research grant FPU13/00151 to A.M.-R.].