All EGFR mutations are (not) created equal: focus on uncommon EGFR mutations.

PURPOSE: Most common EGFR mutations in NSCLC include del19 and exon 21 L858R. Approximately 10% of patients have uncommon EGFR mutations (indels, missense mutations involving G719, L861 and S768 codons, and exon 20 insertions) that do not respond to TKIs. METHODS: Of 490 EGFR mutated NSCLC samples, 60 cases harboring uncommon/compound EGFR mutations were reviewed retrospectively, and 44 were included for survival analysis. RESULTS: Sixty (12.2%) patients with a median age of 63 years (25-84 years) had uncommon/compound EGFR mutations. Majority had no history of smoking (52; 86.7%). Most common major uncommon mutations (G719X in exon 18, L861Q in exon 21 and S768I in exon 20) were identified in 19 (31.7%) patients. 17 (28.3%) cases demonstrated exon 20 insertions. De novo T790M was observed in 7 (11.7%) cases and 9 cases exhibited compound/dual mutations. Among the 12 patients who received first-line EGFR TKI, 7 received afatinib. Median progression-free survival of patients following first-line afatinib was 8.13 months, irrespective of mutation type exhibited. Overall response rate to first-line afatinib therapy was 57.1%. CONCLUSION: The current study highlighted that rare/dual EGFR mutations are heterogeneous with distinct clinical features in a large Indian cohort of EGFR mutated patients with NSCLC.

ORF6 protein of SARS-CoV-2 inhibits TRIM25 mediated RIG-I ubiquitination to mitigate type I IFN induction.

Evasion and antagonism of host cellular immunity upon SARS-CoV-2 infection confers a profound replication advantage on the virus and contributes to COVID-19 pathogenesis. We explored the ability of different SARS-CoV-2 proteins to antagonize the host innate immune system and found that the ORF6 protein mitigated type-I IFN (interferon) induction and downstream IFN signaling. Our findings also corroborated previous reports that ORF6 blocks the nuclear import of IRF3 and STAT1 to inhibit IFN induction and signaling. Here we show that ORF6 directly interacts with RIG-I and blocks downstream type-I IFN induction and signaling by inhibiting K-63 linked ubiquitination of RIG-I by the E3 Ligase TRIM25. This involves ORF6-mediated targeting of TRIM25 for degradation, also observed during SARS-CoV-2 infection. The type-I IFN antagonistic activity of ORF6 was mapped to its C-terminal cytoplasmic tail, specifically to amino acid residues 52-61. Overall, we provide new insights into how the SARS-CoV-2 ORF6 protein inhibits type I-IFN induction and signaling through distinct mechanisms.

A natural broad-spectrum inhibitor of enveloped virus entry, effective against SARS-CoV-2 and Influenza A Virus in preclinical animal models.

The COVID-19 pandemic has highlighted the need for novel antivirals for pandemic management and preparedness. Targeting host processes that are co-opted by viruses is an attractive strategy for developing antivirals with a high resistance barrier. Picolinic acid (PA) is a byproduct of tryptophan metabolism, endogenously produced in humans and other mammals. Here we report broad-spectrum antiviral effects of PA against enveloped viruses, including Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), Influenza A virus (IAV), Flaviviruses, Herpes Simplex Virus, and Human Parainfluenza Virus. We further demonstrate using animal models that PA is effective against SARS-CoV-2 and IAV, especially as an oral prophylactic. The mode of action studies revealed that PA inhibits viral entry of enveloped viruses, primarily by interfering with viral-cellular membrane fusion, inhibiting virus-mediated syncytia formation, and dysregulating cellular endocytosis. Overall, our data establish PA as a broad-spectrum antiviral agent, with promising preclinical efficacy against pandemic viruses SARS-CoV-2 and IAV.