Resistance to osimertinib in advanced EGFR-mutated NSCLC: a prospective study of molecular genotyping on tissue and liquid biopsies.

BACKGROUND: Resistance to osimertinib in advanced EGFR-mutated non-small cell lung cancer (NSCLC) constitutes a significant challenge for clinicians either in terms of molecular diagnosis and subsequent therapeutic implications. METHODS: This is a prospective single-centre study with the primary objective of characterising resistance mechanisms to osimertinib in advanced EGFR-mutated NSCLC patients treated both in first- and in second-line. Next-Generation Sequencing analysis was conducted on paired tissue biopsies and plasma samples. A concordance analysis between tissue and plasma was performed. RESULTS: Sixty-five advanced EGFR-mutated NSCLC patients treated with osimertinib in first- (n = 56) or in second-line (n = 9) were included. We managed to perform tissue and liquid biopsies in 65.5% and 89.7% of patients who experienced osimertinib progression, respectively. Acquired resistance mechanisms were identified in 80% of 25 patients with post-progression samples, with MET amplification (n = 8), EGFR C797S (n = 3), and SCLC transformation (n = 2) the most frequently identified. The mean concordance rates between tissue and plasma for the EGFR activating mutation and for the molecular resistance mechanisms were 87.5% and 22.7%, respectively. CONCLUSIONS: Resistance to osimertinib demonstrated to be highly heterogeneous, with MET amplification the main mechanism. Plasma genotyping is a relevant complementary tool which might integrate tissue analysis for the study of resistance mechanisms.

PD-L1 overexpression induces STAT signaling and promotes the secretion of pro-angiogenic cytokines in non-small cell lung cancer (NSCLC).

BACKGROUND: Monoclonal antibodies (ICI) targeting the immune checkpoint PD-1/PD-L1 alone or in combination with chemotherapy have demonstrated relevant benefits and established new standards of care in first-line treatment for advanced non-oncogene addicted non-small cell lung cancer (NSCLC). However, a relevant percentage of NSCLC patients, even with high PD-L1 expression, did not respond to ICI, highlighting the presence of intracellular resistance mechanisms that could be dependent on high PD-L1 levels. The intracellular signaling induced by PD-L1 in tumor cells and their correlation with angiogenic signaling pathways are not yet fully elucidated. METHODS: The intrinsic role of PD-L1 was initially checked in two PD-L1 overexpressing NSCLC cells by transcriptome profile and kinase array. The correlation of PD-L1 with VEGF, PECAM-1, and angiogenesis was evaluated in a cohort of advanced NSCLC patients. The secreted cytokines involved in tumor angiogenesis were assessed by Luminex assay and their effect on Huvec migration by a non-contact co-culture system. RESULTS: PD-L1 overexpressing cells modulated pathways involved in tumor inflammation and JAK-STAT signaling. In NSCLC patients, PD-L1 expression was correlated with high tumor intra-vasculature. When challenged with PBMC, PD-L1 overexpressing cells produced higher levels of pro-angiogenic factors compared to parental cells, as a consequence of STAT signaling activation. This increased production of cytokines involved in tumor angiogenesis largely stimulated Huvec migration. Finally, the addition of the anti-antiangiogenic agent nintedanib significantly reduced the spread of Huvec cells when exposed to high levels of pro-angiogenic factors. CONCLUSIONS: In this study, we reported that high PD-L1 modulates STAT signaling in the presence of PBMC and induces pro-angiogenic factor secretion. This could enforce the role of PD-L1 as a crucial regulator of the tumor microenvironment stimulating tumor progression, both as an inhibitor of T-cell activity and as a promoter of tumor angiogenesis.

SLC22A2 variants and dolutegravir levels correlate with psychiatric symptoms in persons with HIV.

BACKGROUND: Neuropsychiatric symptoms (NPs) have been reported with dolutegravir use. We hypothesized that increasing dolutegravir trough concentrations (Ctrough) and/or polymorphism in the SLC22A2 gene, encoding the organic cation transporter-2 (OCT2), which is involved in monoamine clearance in the CNS and is inhibited by dolutegravir, might be associated with NPs. METHODS: A cross-sectional cohort of HIV-positive patients treated with a dolutegravir-containing regimen underwent determination of allelic discrimination for SLC22A2 808 C → A polymorphism and dolutegravir Ctrough. The Symptom Checklist-90-R [investigating 10 psychiatric dimensions and reporting a general severity index (GSI)], a self-reported questionnaire and the Mini-International Neuropsychiatric Interview were offered to investigate current NPs. The effects of dolutegravir Ctrough and the SLC22A2 gene variant on NPs were explored by multivariable logistic regression. RESULTS: A cohort of 203 patients was analysed: 71.4% were male, with median age 51 years and 11 years of ART exposure. Median time on dolutegravir was 18 months. Dolutegravir was associated with different antiretroviral combinations (mainly lamivudine, 38.9%, and abacavir/lamivudine, 35.5%). SLC22A2 CA genotype was independently associated with an abnormal GSI [adjusted OR (aOR) 2.43; P = 0.072], anxiety (aOR 2.61; P = 0.044), hostility (aOR 3.76; P = 0.012) and with moderate to severe headache (aOR 5.55; P = 0.037), and dolutegravir Ctrough was associated with hostility (fourth versus first quartile aOR 6.70; P = 0.007) and psychoticism (fourth versus first quartile aOR 19.01; P = 0.008). Other NPs were not associated with SLC22A2 polymorphism or dolutegravir Ctrough. CONCLUSIONS: A variant of the OCT2-encoding gene, in addition to or in synergy with higher dolutegravir Ctrough, is associated with a set of NPs observed during dolutegravir therapy.

Cell size reduction induced by inhibition of the mTOR/S6K-signaling pathway protects Jurkat cells from apoptosis.

In Jurkat cells, the decreased cell growth rate associated with a long-lasting deactivation of the mammalian target of rapamycin (mTOR)/p70 ribosomal S6 kinase (S6K)-signaling pathway generates a cell population of progressively reduced cellular mass and size. When promoted by rapamycin as prototype inhibitor, the mTOR deactivation-dependent cell size reduction was associated with slowed, but not suppressed, proliferation. Small-size cells were significantly protected from apoptosis induced by Fas/Apo-1 death-receptor activation (as shown by reduced procaspase cleavage and decreased catalytic activity of relevant caspases) or by stress signals-dependent mitochondrial perturbation (as shown by reduced cleavage of caspase-2, lower dissipation of mitochondrial membrane potential and decreased release of cytochorome c and apoptosis-inducing factor from mitochondria). Protection faded when reactivation of the mTOR/S6K pathway promoted the cell recovery to normal size. These results suggest that cells induced to reduce their mass by the mTOR deactivation-dependent inhibition of cell growth become more resilient to lethal assaults by curbing the cell's suicidal response.