Dual inhibition of MEK and PI3Kß/δ-a potential therapeutic strategy in PTEN-wild-type docetaxel-resistant metastatic prostate cancer.

Background: Docetaxel remains the standard treatment for metastatic castration-resistant prostate cancer (mCRPC). However, resistance frequently emerges as a result of hyperactivation of the PI3K/AKT and the MEK/ERK pathways. Therefore, the inhibition of these pathways presents a potential therapeutic approach. In this study, we evaluated the efficacy of simultaneous inhibition of the PI3K/AKT and MEK/ERK pathways in docetaxel-resistant mCRPC, both in vitro and in vivo. Methods: Docetaxel-sensitive and docetaxel-resistant mCRPC cells were treated with selumetinib (MEK1/2 inhibitor), AZD8186 (PI3Kß/δ inhibitor) and capivasertib (pan-AKT inhibitor) alone and in combination. Efficacy and toxicity of selumetinib+AZD8186 were tested in docetaxel-resistant xenograft mice. CRISPR-Cas9 generated a PTEN-knockdown docetaxel-resistant cell model. Changes in phosphorylation of AKT, ERK and downstream targets were analyzed by Western blot. Antiapoptotic adaptations after treatments were detected by dynamic BH3 profiling. Results: PI3K/AKT and MEK/ERK pathways were hyperactivated in PTEN-wild-type (wt) docetaxel-resistant cells. Selumetinib+AZD8186 decreased cell proliferation and increased apoptosis in PTEN-wt docetaxel-resistant cells. This observation was further confirmed in vivo, where docetaxel-resistant xenograft mice treated with selumetinib+AZD8186 exhibited reduced tumor growth without additional toxicity. Conclusion: Our findings on the activity of selumetinib+AZD8186 in PTEN-wt cells and in docetaxel-resistant xenograft mice provide an excellent rationale for a novel therapeutic strategy for PTEN-wt mCRPC patients resistant to docetaxel, in whom, unlike PTEN-loss patients, a clinical benefit of treatment with single-agent PI3K and AKT inhibitors has not been demonstrated. A phase I-II trial of this promising combination is warranted.

Role of Siglecs in viral infections: A double-edged sword interaction.

Sialic-acid-binding immunoglobulin-like lectins are cell surface immune receptors known as Siglecs that play a paramount role as modulators of immunity. In recent years, research has underscored how the underlaying biology of this family of receptors influences the outcome of viral infections. While Siglecs are needed to promote effective antiviral immune responses, they can also pave the way to viral dissemination within tissues. Here, we review how recent preclinical findings focusing on the interplay between Siglecs and viruses may translate into promising broad-spectrum therapeutic interventions or key biomarkers to monitor the course of viral infections.

Non-Small-Cell Lung Cancer Signaling Pathways, Metabolism, and PD-1/PD-L1 Antibodies.

Treatment of advanced (metastatic) non-small-cell lung cancer (NSCLC) is currently mainly based on immunotherapy with antibodies against PD-1 or PD-L1, alone, or in combination with chemotherapy. In locally advanced NSCLC and in early resected stages, immunotherapy is also employed. Tumor PD-L1 expression by immunohistochemistry is considered the standard practice. Response rate is low, with median progression free survival very short in the vast majority of studies reported. Herein, numerous biological facets of NSCLC are described involving driver genetic lesions, mutations ad fusions, PD-L1 glycosylation, ferroptosis and metabolic rewiring in NSCLC and lung adenocarcinoma (LUAD). Novel concepts, such as immune-transmitters and the effect of neurotransmitters in immune evasion and tumor growth, the nascent relevance of necroptosis and pyroptosis, possible new biomarkers, such as gasdermin D and gasdermin E, the conundrum of K-Ras mutations in LUADs, with the growing recognition of liver kinase B1 (LKB1) and metabolic pathways, including others, are also commented. The review serves to charter diverse treatment solutions, depending on the main altered signaling pathways, in order to have effectual immunotherapy. Tumor PDCD1 gene (encoding PD-1) has been recently described, in equilibrium with tumor PD-L1 (encoded by PDCD1LG1). Such description explains tumor hyper-progression, which has been reported in several studies, and poises the fundamental criterion that IHC PD-L1 expression as a biomarker should be revisited.