EGFR-Mediated Reactivation of MAPK Signaling Induces Acquired Resistance to GSK2118436 in BRAF V600E–Mutant NSCLC Cell Lines

Mechanisms of resistance to targeted therapy and immunotherapy in non-small cell lung cancer: promising strategies to overcoming challenges

Resistance to targeted therapy and immunotherapy in non-small cell lung cancer (NSCLC) is a significant challenge in the treatment of this disease. The mechanisms of resistance are multifactorial and include molecular target alterations and activation of alternative pathways, tumor heterogeneity and tumor microenvironment change, immune evasion, and immunosuppression. Promising strategies for overcoming resistance include the development of combination therapies, understanding the resistance mechanisms to better use novel drug targets, the identification of biomarkers, the modulation of the tumor microenvironment and so on. Ongoing research into the mechanisms of resistance and the development of new therapeutic approaches hold great promise for improving outcomes for patients with NSCLC. Here, we summarize diverse mechanisms driving resistance to targeted therapy and immunotherapy in NSCLC and the latest potential and promising strategies to overcome the resistance to help patients who suffer from NSCLC.

RICK regulates the odontogenic differentiation of dental pulp stem cells through activation of TNF-α via the ERK and not through NF-κB signaling pathway

Dental pulp stem cells (DPSCs) are capable of both self-renewal and multilineage differentiation, which play a positive role in dentinogenesis. Studies have shown that tumor necrosis factor-α (TNF-α) is involved in the differentiation of DPSCs under pro-inflammatory stimuli, but the mechanism of action of TNF-α is unknown. Rip-like interacting caspase-like apoptosis-regulatory protein kinase (RICK) is a biomarker of an early inflammatory response that plays a key role in modulating cell differentiation, but the role of RICK in DPSCs is still unclear. In this study, we identified that RICK regulates TNF-α-mediated odontogenic differentiation of DPSCs via the ERK signaling pathway. The expression of the biomarkers of odontogenic differentiation dental matrix protein-1 (DMP-1), dentin sialophosphoprotein (DSPP), biomarkers of odontogenic differentiation, increased in low concentration (1-10 ng/ml) of TNF-α and decreased in high concentration (50-100 ng/ml). Odontogenic differentiation increased over time in the odontogenic differentiation medium. In the presence of 10 ng/L TNF-α, the expression of RICK increased gradually over time, along with odontogenic differentiation. Genetic silencing of RICK expression reduced the expression of odontogenic markers DMP-1 and DSPP. The ERK, but not the NF-κB signaling pathway, was activated during the odontogenic differentiation of DPSCs. ERK signaling modulators decreased when RICK expression was inhibited. PD98059, an ERK inhibitor, blocked the odontogenic differentiation of DPSCs induced by TNF-α. These results provide a further theoretical and experimental basis for the potential use of RICK in targeted therapy for dentin regeneration.

[Research Progress of Targeted Therapy for BRAF Mutation in Advanced Non-small Cell Lung Cancer]

靶向治疗是驱动基因阳性晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）的重要治疗手段之一。鼠类肉瘤病毒癌基因同源物B1（v-raf murine sar-coma viral oncogene homolog B1, BRAF）基因是继表皮生长因子受体（epidermal growth factor receptor, EGFR）基因突变、间变性淋巴瘤激酶（anaplastic lymphoma kinase, ALK）基因融合和ROS1基因重排之后，NSCLC又一个重要的驱动基因。BRAF V600E突变占BRAF基因突变的一半以上，是晚期NSCLC的潜在治疗靶点，本文主要对BRAF基因突变类型及相关靶向研究进展进行综述。。

Preclinical Evaluation of Vemurafenib as Therapy for BRAFV600E Mutated Sarcomas

The BRAF^V600E mutation, which in melanoma is targetable with vemurafenib, is also found in sarcomas and we here evaluate the therapeutic potential in sarcoma cell lines. Methods: Four sarcoma cell lines harboring the BRAF^V600E mutation, representing liposarcomas (SA-4 and SW872), Ewing sarcoma (A673) and atypical synovial sarcoma (SW982), were treated with vemurafenib and the effects on cell growth, apoptosis, cell cycle progression and cell signaling were determined. Results: Vemurafenib induced a strong cytostatic effect in SA-4 cells, mainly due to cell cycle arrest, whereas only moderate levels of apoptosis were observed. However, a high dose was required compared to BRAF^V600E mutated melanoma cells, and removal of vemurafenib demonstrated that the continuous presence of drug was required for sustained growth inhibition. A limited growth inhibition was observed in the other three cell lines. Protein analyses demonstrated reduced phosphorylation of ERK during treatment with vemurafenib in all the four sarcoma cell lines confirming that the MAPK pathway is active in these cell lines, and that the pathway can be inhibited by vemurafenib, but also that these cells can proliferate despite this. Conclusions: These findings indicate that vemurafenib alone would not be an efficient therapy against BRAF^V600E mutated sarcomas. However, further investigations of combination with other drugs are warranted.

Coxsackieviruses B3 infection of myocardial microvascular endothelial cells activates fractalkine via the ERK1/2 signaling pathway

Infections by pathogens may lead to cardiovascular diseases, including acute/chronic myocarditis. (Coxsackieviruses B3) CVB3 is considered to be the most common causative agent in m‑yocarditis, which can lead to dilated cardiomyopathy. The present study aimed to investigate the mechanism of CVB3‑infected myocardial microvascular endothelial cells. The CVB3 infection was detected by 50% tissue culture infective dose (TCID50). The role of fractalkine (FKN) in the infection was detected using western blotting and RNA interference. To assess mitogen‑activated protein kinase signaling activity, levels of total and phosphorylated extracellular signal‑regulated kinase (ERK)1/2, c‑Jun N‑terminal kinase, and p38 were measured at 0, 20, 40, and 60 min after CVB3 infection by western blot analysis. The results showed that infection activated FKN via the ERK1/2 signaling pathway. Furthermore, the TCID50 of CVB3 in infected cells was lower compared with that in myocardial microvascular endothelial cells following ERK1/2 inhibition and FKN silencing. CVB3 infection of myocardial microvascular endothelial cells activates FKN via the ERK1/2 signaling pathway. These findings represent a foundation for the development of novel methods of treating CVB3‑induced myocarditis.

The impact of MET, IGF-1, IGF1R expression and EGFR mutations on survival of patients with non-small-cell lung cancer

Introduction

To compare the efficacy of silver in situ hybridization (SISH) and immunohistochemistry (IHC) in detecting MET and IGF1R alterations and to investigate their prevalence and prognostic significance. A possible correlation between MET receptor expression, MET gene alterations and the two most frequent occurring EGFR gene mutations was also investigated.

Materials and methods

Stage I to IIIA tumors from 326 patients with NSCLC were immunohistochemically tested for protein expression of MET and IGF-1. Their cytoplasmic expression was compared with the gene copy number of the MET and IGF1Rgenes by SISH in paraffin-embedded, formalin-fixed material. Correlations were made with the immunohistochemical expression of two frequent EGFR mutations and clinicopathological variables. Univariate and multivariate survival analyses was used to evaluate the prognostic efficacy of the tested markers.

Results

In univariate analyses, high cytoplasmic MET expression showed a significant negative prognostic effect in adenocarcinoma patients (p = 0.026). MET gene to chromosome 7 ratio was a significant positive prognostic marker (p = 0.005), probably only due to the highly negative prognostic significance of chromosome 7 polysomy (p = 0.002). High IGF1R gene copy number was a negative prognostic marker for all NSCLC patients (p = 0.037). In the multivariate analysis, polysomy of chromosome 7 in tumor cells correlated significantly and independently with a poor prognosis (p = 0.011). In patients with adenocarcinoma, a high cytoplasmic MET expression was an independent negative prognostic marker (p = 0.013). In males a high IGF1R gene copy number to chromosome 15 count ratio was significantly and independently correlated to a poor prognosis (p = 0.018).

Conclusion

MET protein expression provides superior prognostic information compared with SISH. Polysomy of chromosome 7 is an independent negative prognostic factor in NSCLC patients. This finding has an important implication while examining genes located on chromosome 7 by means of SISH. High IGF1R gene copy number to chromosome 15 count ratio is an independent predictor of inferior survival in male patients with primary NSCLC.