EGFR and KRAS mutations do not enrich for the activation of IL-6, JAK1 or phosphorylated STAT3 in resected lung adenocarcinoma

APE1 shRNA-loaded cancer stem cell-derived extracellular vesicles reverse Erlotinib resistance in non-small cell lung cancer via the IL-6/STAT3 signalling

OBJECTIVE

Apurinic endonuclease 1 (APE1) has been suggested as an oncogene of lung tumours and our bioinformatics analysis identified the association between Erlotinib resistance and interleukin-6 (IL-6). Thus, we performed this work to delineate the mechanistic actions of APE1/IL-6 signalling in Erlotinib resistance of non-small cell lung cancer (NSCLC).

METHODS

We selected human NSCLC cell lines HCC827 and PC9 to establish Erlotinib-resistant HCC827R and PC9R cells. Cancer stem cells (CSCs) were isolated from Erlotinib-sensitive HCC827P and PC9P cells (PCSCs) and from HCC827R and PC9R cells (RCSCs). Further, extracellular vesicles (EVs) were separated from PCSCs (PCSC-EVs) and RCSCs (RCSC-EVs) and co-cultured with RCSCs with or without short hairpin RNA (shRNA)-targeting APE1 (APE1 shRNA) transduction. In addition, functional assays were conducted to determine the effect of APE1 shRNA on malignant phenotypes of cancer cells in vitro and in vivo and the activation of IL-6/STAT3 signalling.

RESULTS

It was found that NSCLC cells could internalize both RCSC-EVs and PCSC-EVs. RCSC-EVs augmented the resistance of NSCLC cells to Erlotinib. The overexpression of APE1 occurred in NSCLC tissues, and IL-6 was enriched in serum samples of patients with NSCLC. APE1 shRNA was demonstrated to restrict the Erlotinib resistance of NSCLC cells by inactivating the IL-6/STAT3 signalling. Additionally, shAPE1-loaded RCSC-EVs suppressed the Erlotinib resistance of NSCLC via the IL-6/STAT3 axis both in vitro and in vivo, as reflected by impeded malignant phenotypes and xenograft tumour formation.

CONCLUSIONS

Collectively, these data indicate that APE1 confers Erlotinib resistance by activating the IL-6/STAT3 signalling, suggesting targeting APE1 as a possible therapeutic target in Erlotinib-resistant NSCLC.

A novel classification based on B-cell receptor signal gene expression correlates with prognosis in primary breast diffuse large B-cell lymphoma

Primary breast diffuse large B-cell lymphoma (PB-DLBCL), the most common histologic subtype of lymphoid malignancy in the breast, is a clinically and genetically heterogeneous disease that has insufficient systematic studies on the pathological and molecular features, optimal treatment scheme, as well as the prognostic factors. The aim of our study was to identify biomarkers and distinct subtypes of PB-DLBCLs and then evaluate the prognosis of this rare malignant lymphoma. We carried out hierarchical clustering analysis to evaluate protein expressions of potential biomarkers detected by immunohistochemistry staining of samples from 68 PB-DLBCL patients. The gene expression data from TCGA database was obtained to validate the identified clusters. We identified three robust clusters based on the B-cell receptor (BCR) signaling pathway, including two recognized NF-κB-dependent and PI3K-dependent clusters, and a distinct subset of PB-DLBCL with NF-κB-independent anti-apoptotic overexpression plus PI3K signaling, which exhibited an evolving definition and distinctive characters of a cluster group. Furthermore, survival analysis results showed an inferior outcome in NF-κB-dependent cluster patients and favorable survival in the PI3K-dependent cluster patients, suggesting an important predictive value of the three clusters. Our study provided a new perspective for understanding clinical complexity of PB-DLBCLs, and gave evidence for finding targeted biomarkers and strategies.

Nuclear Factor κB Signaling and Its Related Non-coding RNAs in Cancer Therapy

Nuclear factor κB (NF-κB) acts as a nuclear factor that is composed of five main subunits. It is a pluripotent and crucial dimer transcription factor that has a close relationship with many serious illnesses, especially its influences on cell proliferation, inflammation, and cancer initiation and progression. NF-κB acts as part of the signaling pathway and determines its effect on the expression of several other genes, such as epidermal growth factor receptor (EGFR), p53, signal transducer and activator of transcription 3 (STAT3), and non-coding RNA (ncRNA). Continuous activation of the NF-κB signaling pathway has been seen in many cancer types. While the NF-κB signaling pathway is tightly regulated in physiological settings, quite frequently it is constitutively activated in cancer, and the molecular biology mechanism underlying the deregulated activation of NF-κB signaling remains unclear. In this review, we discuss the regulatory role and possible clinical significance of ncRNA (microRNA [miRNA] and long non-coding RNA [lncRNA]) in NF-κB signaling in cancer, including in the conversion of inflammation to carcinogenesis. Non-coding RNA plays an essential and complex role in the NF-κB signaling pathway. NF-κB activation can also induce the ncRNA status. Targeting NF-κB signaling by ncRNA is becoming a promising strategy of drug development and cancer treatment.

Tyrosine kinase inhibitor-induced IL-6/STAT3 activation decreases sensitivity of EGFR-mutant non-small cell lung cancer to icotinib

Tyrosine kinase Inhibitors (TKIs) of epidermal growth factor receptor (EGFR) has considerably benefited for non-small cell lung carcinomas (NSCLC) harbor mutations in EGFR. However, the factors attenuating EGFR-TKI efficiency are obstacles to inhibit the proliferation of EGFR-mutant NSCLC cells successfully. Clarifying the insensitivity mechanisms of EGFR-TKI would help to develop new treatment strategy. In this study, the sensitivity of EGFR-mutant NSCLC cell lines, PC9 and HCC827, to icotinib was detected. Similar with other EGFR-TKIs such as gefitinib and erlortinib in previous research, the proliferation of two cell lines was apparently inhibited. However, we surprisingly found that contrast with the suppression of EGFR-AKT/ERK pathway, STAT3 was significantly activated in PC9 cells with the treatment of icotinib, but not in HCC827 cells. Further study confirmed that icotinib concomitantly induced IL-6 secretion and src activation in PC9 cells. Moreover, with the treatment of IL-6 neutralizing antibody or src inhibitor, dasatinib, icotinib-induced phosphorylation of STAT3 was reduced, as well as the sensitivity of PC9 to icotinib was also partially increased. Our results suggest that Src/IL-6/STAT3 bypass pathway is activated to maintain cell survival when the EGFR pathway was inhibited by TKIs, even in some EGFR-mutant NSCLC cells sensitive to TKIs. This finding provides a groundwork for potential combinatorial treatment with TKIs and Src or STAT3 inhibitor to improve icotinib sensitivity.