FGFR1 gene amplification in squamous cell carcinomas of the lung: a potential favorable prognostic marker for women and for patients with advanced cancer

The Role of SCARA5 as a Potential Biomarker in Squamous Cell Carcinoma of the Lung

Lung cancer is the leading cause of cancer-related deaths in the western world. Squamous cell carcinoma is one of the most common histological subtypes of this malignancy. For squamous cell carcinoma of the lung (LSCC), prognostic and predictive markers still are largely missing. In a previous study, we were able to show that the expression of THSD7A shows an association with unfavorable prognostic parameters in prostate cancer. There is also a link to a high expression of FAK. There is incidence that SCARA5 might be the downstream gene of THSD7A. Furthermore, there is evidence that SCARA5 interacts with FAK. We were interested in the role of SCARA5 as a potential biomarker in LSCC. Furthermore, we wanted to know whether SCARA5 expression is linked to THSD7A positivity and to the expression level of FAK. For this reason, we analyzed 101 LSCC tumors by immunohistochemistry. Tissue microarrays were utilized. No significant association was found between SCARA5 expression and overall survival or clinicopathological parameters. There was also no significant association between THSD7A positivity and SCARA5 expression level. Moreover, no significant association was found between FAK expression level and SCARA5 expression level. SCARA5 seems not to play a major role as a biomarker in squamous cell carcinoma of the lung.

Expression and Purification of FGFR1-Fc Fusion Protein and Its Effects on Human Lung Squamous Carcinoma

Molecular-targeted therapies for lung squamous cell carcinoma (LSCC) are limited mainly because targetable oncogenic aberrations are absent in LSCC. Recent genomic analyses have revealed that the fibroblast growth factor (FGF) signaling pathway plays a fundamental role in LSCC progression via cancer cell proliferation and angiogenesis. In the present study, we designed, expressed, and purified a fibroblast growth factor receptor fragment (FGFR1-Fc) fusion protein using NS/0 cells. In FGF2-FGFR1 overexpressed NCI-H1703 cells, the FGFR1-Fc fusion protein effectively inhibited proliferation and invasion and arrested the cell cycle at the G0-G1 phase. In NCI-H1703 cells treated with the FGFR1-Fc fusion protein, the phosphorylation levels of FGFR1, FRS2, ERK, and AKT were significantly reduced. Using an siRNA assay, we demonstrated that FGF2-FGFR1 is the major anti-tumor target of FGFR1-Fc fusion the FGFR1-Fc fusion protein, which also significantly inhibited proliferation and invasion by NCI-H1703 cells via the FGF2-FGFR1 signaling pathway. In addition, the FGFR1-Fc fusion protein significantly inhibited angiogenesis in an embryonic chorioallantoic membrane model. The FGFR1-Fc fusion protein may be an effective therapeutic candidate for LSCC.

THSD7A Positivity Predicts Poor Survival and Is Linked to High FAK Expression and FGFR1-Wildtype in Female Patients with Squamous Cell Carcinoma of the Lung

Lung cancer is the leading cause of cancer-related deaths in the western world, with squamous cell carcinoma being one of the most common histological subtypes. Prognostic and predictive markers are still largely missing for squamous cell carcinoma of the lung (LSCC). Several studies indicate that THSD7A might at least play a role in the prognosis of different tumors. FAK seems to play an important role in lung cancer and is discussed as a potential therapeutic target. In addition, there is evidence that FAK-dependent signaling pathways might be affected by THSD7A. For that reason, we investigated the role of THSD7A as a potential tumor marker in LSCC and whether THSD7A expression has an impact on the expression level of FAK. A total of 101 LSCCs were analyzed by immunohistochemistry using tissue microarrays. THSD7A positivity was associated with poor overall survival in female patients and showed a relation to high FAK expression in this subgroup. To our knowledge, we are the first to report these correlations in lung cancer. The results might be proof of the assumed activation of FAK-dependent signaling pathways by THSD7A and that as a membrane-associated protein, THSD7A might serve as a putative therapeutic target in LSCC.

FGFR1-4 RNA-Based Gene Alteration and Expression Analysis in Squamous Non-Small Cell Lung Cancer

While fibroblast growth factor receptors (FGFRs) are involved in several biological pathways and FGFR inhibitors may be useful in the treatment of squamous non-small cell lung cancer (Sq-NSCLC), FGFR aberrations are not well characterized in Sq-NSCLC. We comprehensively evaluated FGFR expression, fusions, and variants in 40 fresh-frozen primary Sq-NSCLC (stage IA3−IV) samples and tumor-adjacent normal tissues using real-time PCR and next-generation sequencing (NGS). Protein expression of FGFR1−3 and amplification of FGFR1 were also analyzed. FGFR1 and FGFR4 median gene expression was significantly (p < 0.001) decreased in tumors compared with normal tissue. Increased FGFR3 expression enhanced the recurrence risk (hazard ratio 4.72, p = 0.029), while high FGFR4 expression was associated with lymph node metastasis (p = 0.036). Enhanced FGFR1 gene expression was correlated with FGFR1 protein overexpression (r = 0.75, p = 0.0003), but not with FGFR1 amplification. NGS revealed known pathogenic FGFR2,3 variants, an FGFR3::TACC3 fusion, and a novel TACC1::FGFR1 fusion together with FGFR1,2 variants of uncertain significance not previously reported in Sq-NSCLC. These findings expand our knowledge of the Sq-NSCLC molecular background and show that combining different methods increases the rate of FGFR aberrations detection, which may improve patient selection for FGFRi treatment.

Fibroblast Growth Factor Receptor 1-4 Genetic Aberrations as Clinically Relevant Biomarkers in Squamous Cell Lung Cancer

Fibroblast growth factor receptor (FGFR) inhibitors (FGFRis) are a potential therapeutic option for squamous non-small cell lung cancer (Sq-NSCLC). Because appropriate patient selection is needed for targeted therapy, molecular profiling is key to discovering candidate biomarker(s). Multiple FGFR aberrations are present in Sq-NSCLC tumors-alterations (mutations and fusions), amplification and mRNA/protein overexpression-but their predictive potential is unclear. Although FGFR1 amplification reliability was unsatisfactory, FGFR mRNA overexpression, mutations, and fusions are promising. However, currently their discriminatory power is insufficient, and the available clinical data are from small groups of Sq-NSCLC patients. Here, we focus on FGFR aberrations as predictive biomarkers for FGFR-targeting agents in Sq-NSCLC. Known and suggested molecular determinants of FGFRi resistance are also discussed.

Targeting the Fibroblast Growth Factor Receptor (FGFR) Family in Lung Cancer

Lung cancer is the most common cause of cancer-related deaths globally. Genetic alterations, such as amplifications, mutations and translocations in the fibroblast growth factor receptor (FGFR) family have been found in non-small cell lung cancer (NSCLC) where they have a role in cancer initiation and progression. FGFR aberrations have also been identified as key compensatory bypass mechanisms of resistance to targeted therapy against mutant epidermal growth factor receptor (EGFR) and mutant Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) in lung cancer. Targeting FGFR is, therefore, of clinical relevance for this cancer type, and several selective and nonselective FGFR inhibitors have been developed in recent years. Despite promising preclinical data, clinical trials have largely shown low efficacy of these agents in lung cancer patients with FGFR alterations. Preclinical studies have highlighted the emergence of multiple intrinsic and acquired resistance mechanisms to FGFR tyrosine kinase inhibitors, which include on-target FGFR gatekeeper mutations and activation of bypass signalling pathways and alternative receptor tyrosine kinases. Here, we review the landscape of FGFR aberrations in lung cancer and the array of targeted therapies under clinical evaluation. We also discuss the current understanding of the mechanisms of resistance to FGFR-targeting compounds and therapeutic strategies to circumvent resistance. Finally, we highlight our perspectives on the development of new biomarkers for stratification and prediction of FGFR inhibitor response to enable personalisation of treatment in patients with lung cancer.

Evidence for frequent concurrent DCUN1D1, FGFR1, BCL9 gene copy number amplification in squamous cell lung cancer

Non-small cell lung cancer (NSCLC) targeted therapies are mostly based on activating mutations and rearrangements which are rare events in Lung Squamous Cell Carcinomas (LUSC). Recently advances in immunotherapy have improved the therapeutic repository for LUSC, but there is still an urgent need for novel targets and biomarkers. We examined 73 cases of LUSC for relative copy number amplification of DCUN1D1, BCL9, FGFR1 and ERBB2 genes and searched for correlations with molecular alterations and clinicopathological characteristics. In our cohort BCL9 gene was amplified in 57.5 % of the cases, followed by DCUN1D1 in 37 %, FGFR1 in 19 % whereas none of the cases were amplified in ERBB2 gene. The majority of the samples exhibited amplification in at least one gene while half of them displayed concurrent amplification of two/three genes. Interestingly, 93 % of the FGFR1 amplified cases were also found co amplified with DCUN1D1 and/or BCL9 genes. Linear correlations were found between BCL9 and DCUN1D1 as well as BCL9 and FGFR1 gene amplification. BCL9 and DCUN1D1 genes' amplification was correlated with poorly differentiated tumors (p = 0.035 and p = 0.056 respectively), implying their possible role in tumor aggressiveness. This is the first study, to the best of our knowledge that examines the correlation of DCUN1D1 and BCL9 genes relative copy number amplification with molecular alterations and clinicopathologic characteristics of squamous cell lung cancer tissue samples. Our findings show concurrent amplification of genes in different chromosomes, with possible involvement in tumor aggressiveness. These results support the complexity of LUSC tumorigenesis and imply the necessity of multiple biomarkers / targets for a more effective therapeutic result in LUSC.

FGFR/RACK1 interacts with MDM2, promotes P53 degradation, and inhibits cell senescence in lung squamous cell carcinoma

OBJECTIVE

FGFR is considered an important driver gene of lung squamous cell carcinoma (LSCC). Thus, identification of the biological events downstream of FGFR is important for the treatment of this malignancy. Our previous study has shown that the FGFR/RACK1 complex interacts with PKM2 and consequently promotes glycolysis in LSCC cells. However, the biological functions of the FGFR/RACK1 complex remain poorly understood.

METHODS

Anchorage-independent assays and in vivo tumorigenesis assays were performed to evaluate cancer cell malignancy. Distant seeding assays were performed to evaluate cancer cell metastasis. β-gal staining was used to examine cell senescence, and immunoprecipitation assays were performed to examine the interactions among FGFR, RACK1, and MDM2.

RESULTS

FGFR/RACK1 was found to regulate the senescence of LSCC cells. Treatment with PD166866, an inhibitor of FGFR, or knockdown of RACK1 induced senescence in LSCC cells (P < 0.01). A molecular mechanistic study showed that FGFR/RACK1/MDM2 form a complex that promotes the degradation of p53 and thus inhibits cell senescence. PD166866 and RG7112, an MDM2/p53 inhibitor, cooperatively inhibited the colony formation and distal seeding of LSCC cells (P < 0.01), and upregulated the expression of p53 and p21.

CONCLUSIONS

Together, our findings revealed the regulatory roles and mechanisms of FGFR/RACK1 in cell senescence. This understanding should be important in the treatment of LSCC.

Next-Generation Sequencing at High Sequencing Depth as a Tool to Study the Evolution of Metastasis Driven by Genetic Change Events of Lung Squamous Cell Carcinoma

Background: The aim of this study is to report tumoral genetic mutations observed at high sequencing depth in a lung squamous cell carcinoma (SqCC) sample. We describe the findings and differences in genetic mutations that were studied by deep next-generation sequencing methods on the primary tumor and liver metastasis samples. In this report, we also discuss how these differences may be involved in determining the tumor progression leading to the metastasis stage.

Methods: We followed one lung SqCC patient who underwent FDG-PET scan imaging, before and after three months of treatment. We sequenced 26 well-known cancer-related genes, at an average of ~6,000 × sequencing coverage, in two spatially distinct regions, one from a primary lung tumor metastasis and the other from a distal liver metastasis, which was present before the treatment.

Results: A total of 3,922,196 read pairs were obtained across all two samples' sequenced locations. Merged mapped reads showed several variants, from which we selected 36 with high confidence call. While we found 83% of genetic concordance between the distal metastasis and primary tumor, six variants presented substantial discordance. In the liver metastasis sample, we observed three de novo genetic changes, two on the FGFR3 gene and one on the CDKN2A gene, and the frequency of one variant found on the FGFR2 gene has been increased. Two genetic variants in the HRAS gene, which were present initially in the primary tumor, have been completely lost in the liver tumor. The discordant variants have coding consequences as follows: FGFR3 (c.746C>G, p. Ser249Cys), CDKN2A (c.47_50delTGGC, p. Leu16Profs^*9), and HRAS (c.182A>C, p. Gln61Pro). The pathogenicity prediction scores for the acquired variants, assessed using several databases, reported these variants as pathogenic, with a gain of function for FGFR3 and a loss of function for CDKN2A. The patient follow-up using imaging with 18F-FDG PET/CT before and after four cycles of treatment shows discordant tumor progression in metastatic liver compared to primary lung tumor.

Conclusions: Our results report the occurrence of several genetic changes between primary tumor and distant liver metastasis in lung SqCC, among which non-silent mutations may be associated with tumor evolution during metastasis.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.