Fibroblast growth factor-mediated crosstalk in cancer etiology and treatment

Chemical modification of NSC12 leads to a specific FGF-trap with antitumor activity in multiple myeloma

Inhibition of FGF/FGFR signaling is a promising strategy for the treatment of malignances dependent from FGF stimulation, including multiple myeloma (MM). The steroidal derivative NSC12 (compound 1) is a pan-FGF trap endowed with antitumor activity in vivo. Chemical modifications of compound 1 were explored to investigate structure-activity relationships, focusing on the role of the bis(trifluoromethyl)1,3-propanediol chain, the stereochemistry at C20 and functionalization of C3 position. Our studies unveiled compound 25b, the pregnane 3-keto 20R derivative of compound 1 as an effective agent, blocking the proliferation of MM cells in vitro by inhibiting FGF-dependent receptor activation and slowing MM growth in vivo. Importantly, the absence of the hydroxyl group at C3 prevents binding to estrogen receptors, which might concur to the antitumor activity observed for compound 1, leading to a specific FGF/FGFR system inhibitor, and further supporting the role of FGFR in anticancer therapy in MM.

2b or Not 2b: How Opposing FGF Receptor Splice Variants Are Blocking Progress in Precision Oncology

More than ten thousand peer-reviewed studies have assessed the role of fibroblast growth factors (FGFs) and their receptors (FGFRs) in cancer, but few patients have yet benefited from drugs targeting this molecular family. Strategizing how best to use FGFR-targeted drugs is complicated by multiple variables, including RNA splicing events that alter the affinity of ligands for FGFRs and hence change the outcomes of stromal-epithelial interactions. The effects of splicing are most relevant to FGFR2; expression of the FGFR2b splice isoform can restore apoptotic sensitivity to cancer cells, whereas switching to FGFR2c may drive tumor progression by triggering epithelial-mesenchymal transition. The differentiating and regulatory actions of wild-type FGFR2b contrast with the proliferative actions of FGFR1 and FGFR3, and may be converted to mitogenicity either by splice switching or by silencing of tumor suppressor genes such as CDH1 or PTEN. Exclusive use of small-molecule pan-FGFR inhibitors may thus cause nonselective blockade of FGFR2 isoforms with opposing actions, undermining the rationale of FGFR2 drug targeting. This splice-dependent ability of FGFR2 to switch between tumor-suppressing and -driving functions highlights an unmet oncologic need for isoform-specific drug targeting, e.g., by antibody inhibition of ligand-FGFR2c binding, as well as for more nuanced molecular pathology prediction of FGFR2 actions in different stromal-tumor contexts.

Inhibition of relaxin autocrine signaling confers therapeutic vulnerability in ovarian cancer

Ovarian cancer (OC) is the most deadly gynecological malignancy, with unmet clinical need for new therapeutic approaches. The relaxin peptide is a pleiotropic hormone with reproductive functions in the ovary. Relaxin induces cell growth in several types of cancer, but the role of relaxin in OC is poorly understood. Here, using cell lines and xenograft models, we demonstrate that relaxin and its associated GPCR RXFP1 form an autocrine signaling loop essential for OC in vivo tumorigenesis, cell proliferation, and viability. We determined that relaxin signaling activates expression of prooncogenic pathways, including RHO, MAPK, Wnt, and Notch. We found that relaxin is detectable in patient-derived OC tumors, ascites, and serum. Further, inflammatory cytokines IL-6 and TNF-α activated transcription of relaxin via recruitment of STAT3 and NF-κB to the proximal promoter, initiating an autocrine feedback loop that potentiated expression. Inhibition of RXFP1 or relaxin increased cisplatin sensitivity of OC cell lines and abrogated in vivo tumor formation. Finally, we demonstrate that a relaxin-neutralizing antibody reduced OC cell viability and sensitized cells to cisplatin. Collectively, these data identify the relaxin/RXFP1 autocrine loop as a therapeutic vulnerability in OC.

The FGF/FGFR System in Breast Cancer: Oncogenic Features and Therapeutic Perspectives

One of the major challenges in the treatment of breast cancer is the heterogeneous nature of the disease. With multiple subtypes of breast cancer identified, there is an unmet clinical need for the development of therapies particularly for the less tractable subtypes. Several transduction mechanisms are involved in the progression of breast cancer, therefore making the assessment of the molecular landscape that characterizes each patient intricate. Over the last decade, numerous studies have focused on the development of tyrosine kinase inhibitors (TKIs) to target the main pathways dysregulated in breast cancer, however their effectiveness is often limited either by resistance to treatments or the appearance of adverse effects. In this context, the fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) system represents an emerging transduction pathway and therapeutic target to be fully investigated among the diverse anti-cancer settings in breast cancer. Here, we have recapitulated previous studies dealing with FGFR molecular aberrations, such as the gene amplification, point mutations, and chromosomal translocations that occur in breast cancer. Furthermore, alterations in the FGF/FGFR signaling across the different subtypes of breast cancer have been described. Next, we discussed the functional interplay between the FGF/FGFR axis and important components of the breast tumor microenvironment. Lastly, we pointed out the therapeutic usefulness of FGF/FGFR inhibitors, as revealed by preclinical and clinical models of breast cancer.

Differential responses to kinase inhibition in FGFR2-addicted triple negative breast cancer cells: a quantitative phosphoproteomics study

Fibroblast Growth Factor (FGF) dependent signalling is frequently activated in cancer by a variety of different mechanisms. However, the downstream signal transduction pathways involved are poorly characterised. Here a quantitative differential phosphoproteomics approach, SILAC, is applied to identify FGF-regulated phosphorylation events in two triple- negative breast tumour cell lines, MFM223 and SUM52, that exhibit amplified expression of FGF receptor 2 (FGFR2) and are dependent on continued FGFR2 signalling for cell viability. Comparative Gene Ontology proteome analysis revealed that SUM52 cells were enriched in proteins associated with cell metabolism and MFM223 cells enriched in proteins associated with cell adhesion and migration. FGFR2 inhibition by SU5402 impacts a significant fraction of the observed phosphoproteome of these cells. This study expands the known landscape of FGF signalling and identifies many new targets for functional investigation. FGF signalling pathways are found to be flexible in architecture as both shared, and divergent, responses to inhibition of FGFR2 kinase activity in the canonical RAF/MAPK/ERK/RSK and PI3K/AKT/PDK/mTOR/S6K pathways are identified. Inhibition of phosphorylation-dependent negative-feedback pathways is observed, defining mechanisms of intrinsic resistance to FGFR2 inhibition. These findings have implications for the therapeutic application of FGFR inhibitors as they identify both common and divergent responses in cells harbouring the same genetic lesion and pathways of drug resistance.

LCTL Is a Prognostic Biomarker and Correlates With Stromal and Immune Infiltration in Gliomas

Immune evasion in glioma strongly correlates with clinical outcomes; however, the molecular mechanisms driving the maintenance of immunosuppression remain largely unknown. Recently studies demonstrate that Klothos are aberrantly expressed in several cancers and are potential therapeutic targets in cancers. However, their roles are still unclear in glioma. Here, we show that LCTL is highly expressed in gliomas and that its expression is regulated by DNA methylation status at the promoter. LCTL expression is also found to be significantly associated with high tumor aggressiveness and poor outcomes for glioma patients. Mechanistically, results suggested that LCTL might play an important immunosuppressive role by recruiting immunosuppressive cells and regulating tumor-associated macrophages polarization, T cell exhaustion, and epithelial–mesenchymal transition through FGF signaling in glioma. Our results establish LCTL as a key biomarker for prognosis that could be considered a potential epigenetic and immunotherapeutic target for treatment.

Oncological Risk in Autologous Stem Cell Donation for Novel Tissue-Engineering Approaches to Postmastectomy Breast Regeneration

Adipose tissue engineering using adipose-derived stem cells (ADSCs) has emerged as an opportunity to develop novel approaches to postmastectomy breast reconstruction with the potential for an autologous tissue source with a natural appearance and texture. As of yet, the role of ADSCs in breast cancer development and metastasis is not completely understood; therefore, we must consider the oncological safety of employing an autologous source of ADSCs for use in breast regeneration. This study investigated the regenerative properties of ADSCs isolated from breast cancer patients, including those who had received neoadjuvant chemotherapy, and noncancer controls. The ADSCs were characterised for several parameters central to tissue regeneration, including cell viability, proliferation, differentiation potential, and cytokine secretion. A stem cell population was isolated and confirmed by flow cytometry and multilineage differentiation. There was no difference in cell phenotype or surface antigen expression between ADSCs from different sources. Adipose-derived stem cells isolated from the breast of cancer patients exhibited reduced adipogenic differentiation potential compared with ADSCs from other sources. The greatest degree of adipogenic differentiation was observed in ADSCs isolated from the subcutaneous abdominal fat of noncancer controls. The proliferation rate of ADSCs isolated from the breast of cancer patients was increased compared with other sources; however, it was decreased in ADSCs isolated from breast cancer patients who had recently been treated with neoadjuvant chemotherapy. A number of cytokines were detected in the cell conditioned media of ADSCs from different sources, including matrix metalloproteinase-2 (MMP-2), which was detected at higher levels in the secretome of ADSCs from breast cancer patients compared with noncancer controls. This study provides important information relating to the suitability of ADSCs as an autologous cell source for adipose tissue engineering in postcancer reconstruction. Results indicate that while the surface phenotype does not differ, the differentiation capacity, proliferative rate, and secreted cytokine profile are affected by the presence or treatment of breast cancer. These findings support further investigation into the regenerative potential of these ADSCs, if they are to be considered in clinical reconstructive strategies.

Integrated Analysis of Transcriptome and Prognosis Data Identifies FGF22 as a Prognostic Marker of Lung Adenocarcinoma

Lung adenocarcinoma is one of the most common cancers worldwide. However, the molecular mechanisms of lung adenocarcinoma development are still unclear. This study aimed to investigate the expression profiles of anti-lung cancer target genes in different cancer stages and to explore their functions in tumor development. Lung adenocarcinoma transcriptome and clinical data were downloaded from Genomic Data Commons Data Portal, and the anti-lung cancer target genes were retrieved from the Thomson Reuters Integrity database. The results showed that 16 anti-lung target genes were deregulated in all stages. Among these target genes, fibroblast growth factor 22 showed the most important role in transcription regulatory networks. Further analysis revealed that APC, BRIP1, and PTTG1 may regulate fibroblast growth factor 22 and subsequently influence MAPK signaling pathway, Rap1 signaling pathways, and other tumorigenic processes in all stages. Moreover, high fibroblast growth factor 22 expression leads to poor overall survival (hazard ratio = 1.55, P = .019). These findings provide valuable information for the pathological research and treatment of lung adenocarcinoma. Future studies are needed to verify these results.

Emerging Roles of Fibroblast Growth Factor 10 in Cancer

Whilst cross-talk between stroma and epithelium is critical for tissue development and homeostasis, aberrant paracrine stimulation can result in neoplastic transformation. Chronic stimulation of epithelial cells with paracrine Fibroblast Growth Factor 10 (FGF10) has been implicated in multiple cancers, including breast, prostate and pancreatic ductal adenocarcinoma. Here, we examine the mechanisms underlying FGF10-induced tumourigenesis and explore novel approaches to target FGF10 signaling in cancer.