Profiles, diagnostic process, and patterns of care of patients with stage III non-small cell lung cancer: A French national study.

BACKGROUND: The management of stage III non-small-cell lung cancer (NSCLC) remains heterogeneous and complex, even after the approval of immune checkpoint inhibitors post-chemoradiotherapy (CRT). This observational study from France evaluated real-world practices in managing stage III NSCLC. METHODS: Between 2020 and 2022, we conducted a physician practice survey in 41 medical centers across France, and retrospectively analyzed aggregated information from 417 consecutive charts of patients with stage III NSCLC. We collected information on diagnostic and staging procedures, biomarker testing, surgical and non-surgical treatments, and follow-up. RESULTS: According to the physician survey, diagnostic workup of stage III NSCLC primarily relied on positron emission tomography/computed tomography and brain magnetic resonance imaging, performed for the majority of patients in 100 % and 78 % of centers, respectively. Of 417 patient charts, 414 were evaluable with 53 % of patients having stage IIIA disease, 37 % IIIB, and 10 % IIIC. The most common node involvement was N2 (59 %). Programmed death-ligand 1 testing was conducted for 98 % of patients. Invasive staging (mediastinoscopy or endobronchial ultrasound) was performed in 41 % of patients, of whom 83 % had N2 or N3 nodal involvement. Surgical resection was offered to 120 patients (29 %), with 85 % achieving R0 resection. In 292 charts of patients with unresectable stage III NSCLC, 190 patients (65 %) were offered CRT followed by consolidation immunotherapy. Within these patients, concurrent CRT was more frequently employed (52 %) than sequential CRT (13 %). CONCLUSIONS: Diagnostic procedures and treatment modalities in French medical centers generally align with clinical guidelines for stage III NSCLC, except for invasive staging that was less commonly performed than expected.

FLI-1 functionally interacts with PIASxalpha, a member of the PIAS E3 SUMO ligase family.

FLI-1 is a transcription factor of the ETS family that is involved in several developmental processes and that becomes oncogenic when overexpressed or mutated. As the functional regulators of FLI-1 are largely unknown, we performed a yeast two-hybrid screen with FLI-1 and identified the SUMO E3 ligase PIASxalpha/ARIP3 as a novel in vitro and in vivo binding partner of FLI-1. This interaction involved the ETS domain of FLI-1 and required the integrity of the SAP domain of PIASxalpha/ARIP3. SUMO-1 and Ubc9, the ubiquitin carrier protein component in the sumoylation pathway, were also identified as interactors of FLI-1. Both PIASxalpha/ARIP3 and the closely related PIASxbeta isoform specifically enhanced sumoylation of FLI-1 at Lys(67), located in its N-terminal activation domain. PIASxalpha/ARIP3 relocalized the normally nuclear but diffusely distributed FLI-1 protein to PIASxalpha nuclear bodies and repressed FLI-1 transcriptional activation as assessed using different ETS-binding site-dependent promoters and different cell systems. PIASxalpha repressive activity was independent of sumoylation and did not result from inhibition of FLI-1 DNA-binding activity. Analysis of the properties of a series of ARIP3 mutants showed that the repressive properties of PIASxalpha/ARIP3 require its physical interaction with FLI-1, identifying PIASxalpha as a novel corepressor of FLI-1.

Erythroblast transformation by FLI-1 depends upon its specific DNA binding and transcriptional activation properties.

FLI-1 is a transcriptional regulator of the ETS family of proteins. Insertional activation at the FLI-1 locus is an early event in F-murine leukemia virus-induced erythroleukemia. Consistent with its essential role in erythroid transformation, enforced expression of FLI-1 in primary erythroblasts strongly impairs the response of these cells to erythropoietin (Epo), a cytokine essential to erythropoiesis. We show here that point mutations in the ETS domain that abolished FLI-1 binding to specific DNA elements (ETS-binding sites) suppressed the ability of FLI-1 to transform erythroblasts. The exchange of the entire ETS domain (DNA binding domain) of FLI-1 for that of PU.1 changed the DNA binding specificity of FLI-1 for that of PU.1 and impaired FLI-1 transforming properties. In contrast, ETS domain swapping mutants that maintained the DNA binding specificity of FLI-1 did not affect the ability of FLI-1 to transform erythroblasts. Deletion and swapping mutants that failed to inhibit the DNA binding activity of FLI-1 but impaired its transcriptional activation properties were also transformation-defective. Taken together, these results show that both the ability of FLI-1 to inhibit Epo-induced differentiation of erythroblasts and to confer enhanced cell survival in the absence of Epo critically depend upon FLI-1 ETS-binding site-dependent transcriptional activation properties.