Mex-3 RNA binding family member A (MEX3A)/circMPP6 complex promotes colorectal cancer progression by inhibiting autophagy.

RNA-binding proteins (RBPs)-RNA networks have contributed to cancer development. Circular RNAs (circRNAs) are considered as protein recruiters; nevertheless, the patterns of circRNA-protein interactions in colorectal cancer (CRC) are still lacking. Processing bodies (PBs) formed through liquid-liquid phase separation (LLPS) are membrane-less organelles (MLOs) consisting of RBPs and RNA. Previous evidence suggests a connection between PBs dynamics and cancer progression. Despite the increasingly acknowledged crucial role of RBPs and RNA in the accumulation and maintenance of MLOs, there remains a lack of specific research on the interactions between PBs-related RBPs and circRNAs in CRC. Herein, we identify that MEX-3 RNA binding family member A (MEX3A), frequently upregulated in CRC tissues, predicts poorer patient survival. Elevated MEX3A accelerates malignance and inhibits autophagy of CRC cells. Importantly, MEX3A undergoes intrinsically disordered regions (IDRs)-dependent LLPS in the cytoplasm. Specifically, circMPP6 acts as a scaffold to facilitate the interaction between MEX3A and PBs proteins. The MEX3A/circMPP6 complex modulates PBs dynamic and promotes UPF-mediated phosphodiesterase 5A (PDE5A) mRNA degradation, consequently leading to the aggressive properties of CRC cells. Clinically, CRC patients exhibiting high MEX3A expression and low PDE5A expression have the poorest overall survival. Our findings reveal a collaboration between MEX3A and circMPP6 in the regulation of mRNA decay through triggering the PBs aggregation, which provides prognostic markers and/or therapeutic targets for CRC.

Uncommon de novo EGFRT790M-Mutant NSCLC characterized with unique genetic Features: Clinical response and acquired resistance to the third-generation EGFR-TKIs treatment.

INTRODUCTION: The literature on de novo EGFRT790M-mutant patients diagnosed with lung cancer is limited, and there is currently no consensus concerning the most effective treatment protocols. This study aimed to investigate the genomic characteristics of de novoEGFRT790M-mutant non-small cell lung cancer (NSCLC) and provide insights into its clinical response and resistance mechanism to third-generation EGFR-TKIs. METHODS: Next-generation sequencing was utilized to screen a substantial cohort of 4,228 treatment-naïve patients from the Mygene genomic database to identifythe de novo EGFR-T790M mutation. Meanwhile, we recruited 83 individuals diagnosed with lung cancer who harbored de novo EGFRT790M mutation in the real world. In addition, 166 patients who acquired EGFR-T790M mutation after becoming resistant to first- or second-generation EGFR-TKIs were included as a comparison cohort. RESULTS: De novo EGFRT790M mutation identified by next-generation sequencing is rare (∼1.3 %) in Chinese lung cancer patients. The relative variant allele frequency (VAF) of de novo EGFRT790M mutation was either comparable to or significantly lower than those of EGFR-activating mutations. Patients with de novo-T790M mutations exhibited less favorable clinical outcomes when administered third-generation EGFR-TKIs as first-line therapy thanthose with 19del mutationsdue to a high overlap rate in EGFR p.L858R mutation. In patients with a de novo EGFRT790M mutation, no correlation was observed between T790M clonality and treatment outcomes with third-generation EGFR-TKIs. In contrast, the sub-clonality of the T790M mutation detrimentally affected the third-generation EGFR-TKI treatment efficacy in patients with acquired T790M mutation. Potential resistance mechanisms of third-generation EGFR TKIs in NSCLC patients with de novo or acquired EGFRT790M mutations included EGFR p.C797S in cis or EGFR p.E709X mutation, as well as activation of bypass pathways. CONCLUSIONS: The present study characterized the uncommon but unique de novo EGFRT790M-mutant NSCLC and laid a foundation for designing future clinical trials in the setting of uncommon EGFR mutation.

EGFR Oncogenic Mutations in NSCLC Impair Macrophage Phagocytosis and Mediate Innate Immune Evasion Through Up-Regulation of CD47.

INTRODUCTION: EGFR-mutated NSCLC is characterized by an immunosuppressive microenvironment that confers limited clinical effectiveness to anti-PD-1 or PD-L1 antibodies. Despite the discouraging outcomes of immunotherapy, novel immune checkpoints are constantly emerging, among which the specific vulnerability for therapeutic intervention in the context of EGFR-mutated NSCLC remains unresolved. METHODS: Data sets of patient- and cell line-levels were used for screening and mutual validation of association between EGFR mutation and a panel of immune checkpoint-related genes. Regulatory mechanism was elucidated through in vitro manipulation of EGFR signaling pathway and evaluated by immunoblot analysis, quantitative polymerase chain reaction, flow cytometry, immunofluorescence staining, and chromatin immunoprecipitation. In vivo investigation of different therapeutic strategies were conducted using both immunocompetent and immunodeficient mouse models. RESULTS: Among all screened immune checkpoints, CD47 emerged as the candidate most relevant to EGFR activation. Mechanistically, EGFR mutation constitutively activated downstream ERK and AKT pathways to respectively up-regulate the transcriptional factors c-Myc and NF-κB, both of which structurally bound to the promotor region of CD47 and actively transcribed this "don't eat me" signal. Impaired macrophage phagocytosis was observed on introduction of EGFR-sensitizing mutations in NSCLC cell line models, whereas CD47 blockade restored the phagocytic capacity and augmented tumor cell killing in both in vitro and in vivo models. Remarkably, the combination of anti-CD47 antibody with EGFR tyrosine kinase inhibitor revealed an additive antitumor activity compared with monotherapy of either antitumor agent in both immunocompetent and adaptive immunity-deficient mouse models. CONCLUSIONS: EGFR-sensitizing mutation facilitates NSCLC's escape from innate immune attack through up-regulating CD47. Combination therapy incorporating CD47 blockade holds substantial promise for clinical translation in developing more effective therapeutic approaches against EGFR-mutant NSCLC.

Exploration of immunotherapy in advanced pulmonary lymphoepithelioma-like carcinoma.

Pulmonary lymphoepithelioma-like carcinoma (PLELC) is a rare and histologically distinctive subtype of nonsmall cell lung cancer (NSCLC). High expression of programmed death ligand 1 (PD-L1) and scarcity of druggable driver mutations raise the potential of immunotherapy for advanced PELEC. However, evidence on the clinical impact of immune-checkpoint inhibitors (ICIs) remained limited and unconvincing. The present study retrospectively enrolled advanced PLELC patients who received ICIs either as up-front or salvage therapy in SYSUCC between March 15, 2017 and March 15, 2022. The comparative efficacy of chemoimmunotherapy vs chemotherapy in the first-line setting and chemoimmunotherapy vs ICIs monotherapy in the ≥2 line setting was investigated. A total of 96 patients were finally enrolled; 49 PLELC patients received immunotherapy plus platinum-based chemotherapy, while 45 patients received platinum-based chemotherapy as first-line treatment. Patients with chemoimmunotherapy significantly obtain more survival benefits than those receiving chemotherapy (median progression-free survival [PFS]: 15.6 vs 8.6 months, P = .0015). Additionally, patients with chemoimmunotherapy obtained more PFS benefits than those with ICIs monotherapy in the ≥2 line of therapy (median PFS: 21.7 months vs 7.8 months, P = .094). A significant correlation was observed between prognostic nutritional index (PNI) and favorable treatment outcomes in patients receiving first-line chemoimmunotherapy (median PFS: 17.8 months vs 7.6 months, P < .0001). Likewise, patients in the monocyte-to-lymphocyte ratio (MLR)-high group had significantly shorter PFS than the MLR-low group (median PFS: 11.2 months vs not reached, P = .0009). Our study elucidated the superior efficacy of ICIs therapy, especially chemoimmunotherapy in advanced PLELC, which may provide new insight into the role of immunotherapy in advanced PLELC.

Role of antiangiogenic agents in first-line treatment for advanced NSCLC in the era of immunotherapy.

BACKGROUND & OBJECTIVE: "Anti-angiogenetic drugs plus chemotherapy" (anti-angio-chemo) and "immune checkpoint inhibitors plus chemotherapy" (ICI-chemo) are superior to traditional chemotherapy in the first-line treatment of patients with advanced non-small-cell lung cancer (NSCLC). However, in the absence of a direct comparison of ICI-chemo with anti-angio-chemo, the superior one between them has not been decided, and the benefit of adding anti-angiogenetic agents to ICI-chemo remains controversial. This study aimed to investigate the role of antiangiogenic agents for advanced NSCLC in the era of immunotherapy. METHODS: Eligible randomized controlled trials (RCTs) comparing chemotherapy versus therapeutic regimens involving ICIs or anti-angiogenetic drugs were included. Outcomes included progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and rate of grade 3-4 toxicity assessment. R-4.3.1 was utilized to perform the analysis. RESULTS: A total of 54 studies with a sample size of 25,046 were finally enrolled. "Atezolizumab + Bevacizumab + Chemotherapy" significantly improved the ORR compared with "Atezolizumab + Chemotherapy" (Odds ratio (OR) = 2.73, 95% confidence interval (CI): 1.27-5.87). The trend also favored "Atezolizumab + Bevacizumab + Chemotherapy" in PFS and OS (hazard ratio (HR) = 0.71, 95% CI: 0.39-1.31; HR = 0.94, 95% CI: 0.77-1.16, respectively). In addition, "Pembrolizumab + Chemotherapy" and "Camrelizumab + Chemotherapy" significantly prolonged the PFS compared to "Bevacizumab + Chemotherapy" (HR = 0.65, 95% CI: 0.46-0.92; HR = 0.63, 95% CI: 0.41-0.97; respectively). Meanwhile, "Pembrolizumab + Chemotherapy" and "Sintilimab + Chemotherapy" yielded more OS benefits than "Bevacizumab + Chemotherapy" (HR = 0.69, 95% CI: 0.56-0.83; HR = 0.64, 95%CI: 0.46-0.91; respectively). Scheme between "Atezolizumab + Bevacizumab + Chemotherapy" and "Atezolizumab + Chemotherapy" made no significant difference (OR = 1.18, 95%CI: 0.56-2.42) concerning the rate of grade 3-4 toxicity. It seemed that ICI-chemo yielded more improvement in quality-adjusted life-year (QALY) than "Bevacizumab + Chemotherapy" in cost-effectiveness analysis. CONCLUSION: Our results suggest that ICI-chemo is associated with potentially longer survival, better cost-effectiveness outcomes, and comparable safety profiles than anti-angio-chemo. Also, adding bevacizumab to ICI-chemo seemed to provide additional therapeutic benefits without adding treatment burden. Our findings would supplement the current standard of care and help the design of future clinical trials for the first-line treatment of patients with advanced NSCLC.