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Human lung adenosquamous cell carcinoma (LUAS), containing both adenomatous and squamous pathologies, harbors strong plasticity and is significantly associated with poor prognosis. We established an up-to-date comprehensive genomic and transcriptomic landscape of LUAS in 109 Chinese specimens and demonstrated LUAS development via adeno-to-squamous transdifferentiation. Unsupervised transcriptomic clustering and dynamic network biomarker analysis identified an inflammatory subtype as the critical transition stage during LUAS development. Dynamic dysregulation of the counteracting lineage-specific transcription factors (TFs), containing adenomatous TFs NKX2-1 and FOXA2, and squamous TFs TP63 and SOX2, finely tuned the lineage transition via promoting CXCL3/5-mediated neutrophil infiltration. Genomic clustering identified the most malignant subtype featured with STK11-inactivation, and targeting LSD1 through genetic deletion or pharmacological inhibition almost eradicated STK11-deficient lung tumors. These data collectively uncover the comprehensive molecular landscape, oncogenic driver spectrum and therapeutic vulnerability of Chinese LUAS. [ABSTRACT FROM AUTHOR]

Somatic mutations of the chromatin remodeling gene ARID2 are observed in ∼7% of human lung adenocarcinomas (LUADs). However, the role of ARID2 in the pathogenesis of LUADs remains largely unknown. Here we find that ARID2 expression is decreased during the malignant progression of both human and mice LUADs. Using two KrasG12D -based genetically engineered murine models, we demonstrate that ARID2 knockout significantly promotes lung cancer malignant progression and shortens overall survival. Consistently, ARID2 knockdown significantly promotes cell proliferation in human and mice lung cancer cells. Through integrative analyses of ChIP-Seq and RNA-Seq data, we find that Hspa1a is up-regulated by Arid2 loss. Knockdown of Hspa1a specifically inhibits malignant progression of Arid2 -deficient but not Arid2 -wt lung cancers in both cell lines as well as animal models. Treatment with an HSPA1A inhibitor could significantly inhibit the malignant progression of lung cancer with ARID2 deficiency. Together, our findings establish ARID2 as an important tumor suppressor in LUADs with novel mechanistic insights, and further identify HSPA1A as a potential therapeutic target in ARID2-deficient LUADs. [ABSTRACT FROM AUTHOR]

Chromobox 4 (CBX4) is a core component of polycomb-repressive complex 1 with important roles in cancer biology and tissue homeostasis. Aberrant expression of CBX4 has been implicated in several human malignancies. However, its role and underlying mechanisms in the tumorigenesis of lung adenocarcinoma (LUAD) have not been defined in vivo. Here, we found that expression of CBX4 was frequently up-regulated in human LUAD samples and correlated with poor patient survival. Importantly, genetic ablation of CBX4 greatly dampened lung tumor formation and improved survival in the KrasG12D/P53L/L (KP) autochthonous mouse model of LUAD. In addition, CBX4 depletion significantly inhibited proliferation and anchorage-independent growth of KP mouse embryonic fibroblasts. Moreover, ectopic CBX4 expression clearly promoted proliferation and anchorage-independent growth in both human and mouse LUAD cells, whereas silencing of CBX4 exerted opposite effects. Mechanistically, CBX4 promoted growth of LUAD cells through activation of the Wnt/β-catenin pathway. Furthermore, expression levels of CBX4 were positively correlated with β-catenin in human LUAD samples. In conclusion, our data suggest that CBX4 plays an oncogenic role via the Wnt/β-catenin pathway and could serve as a potential therapeutic target in LUAD. [ABSTRACT FROM AUTHOR]

Since the original version of the manuscript was published the lab has moved and the authors were only able to present raw data for one mouse for the 12 week data shown in Supplementary Figure S1g; this is also shown in the appended Raw Data file. The raw data for 4 mice following 8 weeks of treatment from Supplementary Figure S1c are also shown in the appended Raw Data file. [Extracted from the article]