Fibroblast growth factor receptor 4 (FGFR4): a targetable regulator of drug resistance in colorectal cancer

Fibroblast growth factor receptor 4 induced resistance to radiation therapy in colorectal cancer

In colorectal cancer (CRC), fibroblast growth factor receptor 4 (FGFR4) is upregulated and acts as an oncogene. This study investigated the impact of this receptor on the response to neoadjuvant radiotherapy by analyzing its levels in rectal tumors of patients with different responses to the therapy. Cellular mechanisms of FGFR4-induced radioresistance were analyzed by silencing or over-expressing FGFR4 in CRC cell line models. Our findings showed that the FGFR4 staining score was significantly higher in pre-treatment biopsies of non-responsive than responsive patients. Similarly, high expression of FGFR4 inhibited radiation response in cell line models. Silencing or inhibition of FGFR4 resulted in a reduction of RAD51 levels and decreased survival in radioresistant HT29 cells. Increased RAD51 expression rescued cells in the siFGFR4-group. In radiosensitive SW480 and DLD1 cells, enforced expression of FGFR4 stabilized RAD51 protein levels resulting in enhanced clearance of γ-H2AX foci and increased cell survival in the mismatch repair (MMR)-proficient SW480 cells. MMR-deficient DLD1 cells are defective in homologous recombination repair and no FGFR4-induced radioresistance was observed. Based on our results, FGFR4 may serve as a predictive marker to select CRC patients with MMR-proficient tumors who may benefit from pre-operative radiotherapy.

Multiple faces of fibroblast growth factor-23

PURPOSE OF REVIEW

This review examines the role of fibroblast growth factor-23 (FGF-23) in mineral metabolism, innate immunity and adverse cardiovascular outcomes.

RECENT FINDINGS

FGF-23, produced by osteocytes in bone, activates FGFR/α-Klotho (α-Kl) complexes in the kidney. The resulting bone-kidney axis coordinates renal phosphate reabsorption with bone mineralization, and creates a counter-regulatory feedback loop to prevent vitamin D toxicity. FGF-23 acts to counter-regulate the effects of vitamin D on innate immunity and cardiovascular responses. FGF-23 is ectopically expressed along with α-Kl in activated macrophages, creating a proinflammatory paracrine signaling pathway that counters the antiinflammatory actions of vitamin D. FGF-23 also inhibits angiotensin-converting enzyme 2 expression and increases sodium reabsorption in the kidney, leading to hypertension and left ventricular hypertrophy. Finally, FGF-23 is purported to cause adverse cardiac and impair neutrophil responses through activation of FGFRs in the absence of α-Kl. Although secreted forms of α-Kl have FGF-23 independent effects, the possibility of α-Kl independent effects of FGF-23 is controversial and requires additional experimental validation.

SUMMARY

FGF-23 participates in a bone-kidney axis regulating mineral homeostasis, proinflammatory paracrine macrophage signaling pathways, and in a bone-cardio-renal axis regulating hemodynamics that counteract the effects of vitamin D.

Genomics alterations of metastatic and primary tissues across 15 cancer types

Metastasis is an important event for cancer evolution and prognosis. In this article, we analyzed the differences in genomic alterations between primary and metastatic tissues at hotspot regions in 15 cancer types and 10,456 samples. Differential somatic mutations at the amino acid, protein domain and gene levels, mutational exclusiveness, and copy number variations were identified in these cancers, while no significant nucleotide and gene fusion differences were detected. The homogeneity and heterogeneity of these differences in cancers were also detected. By characterizing the genomic alterations of these genes, important signaling pathways during metastasis were also identified. In summary, the metastatic cancer tissues retained most genomic features of the primary tumor at the biological level and acquired new signatures during cancer cell migration.

Cytotoxic Conjugates of Fibroblast Growth Factor 2 (FGF2) with Monomethyl Auristatin E for Effective Killing of Cells Expressing FGF Receptors

Antibody-drug conjugates (ADCs) are a new class of anticancer therapeutics that combine the selectivity of targeted treatment, ensured by monoclonal antibodies, with the potency of the cytotoxic agent. Here, we applied an analogous approach, but instead of an antibody, we used fibroblast growth factor 2 (FGF2). FGF2 is a natural ligand of fibroblast growth factor receptor 1 (FGFR1), a cell-surface receptor reported to be overexpressed in several types of tumors. We developed and characterized FGF2 conjugates containing a defined number of molecules of highly cytotoxic drug monomethyl auristatin E (MMAE). These conjugates effectively targeted FGFR1-expressing cells, were internalized upon FGFR1-mediated endocytosis, and, in consequence, revealed high cytotoxicity, which was clearly related to the FGFR1 expression level. Among the conjugates tested, the most potent was that bearing three MMAE molecules, showing that the cytotoxicity of protein-drug conjugates in vitro is directly dependent on drug loading.

IBT-based quantitative proteomics identifies potential regulatory proteins involved in pigmentation of purple sea cucumber, Apostichopus japonicus

Sea cucumbers are an important economic species and exhibit high yield value among aquaculture animals. Purple sea cucumbers are very rare and beautiful and have stable hereditary patterns. In this study, isobaric tags (IBT) were first used to reveal the molecular mechanism of pigmentation in the body wall of the purple sea cucumber. We analyzed the proteomes of purple sea cucumber in early pigmentation stage (Pa), mid pigmentation stage (Pb) and late pigmentation stage (Pc), resulting in the identification of 5580 proteins, including 1099 differentially expressed proteins in Pb: Pa and 339 differentially expressed proteins in Pc: Pb. GO and KEGG analyses revealed possible differentially expressed proteins, including"melanogenesis", "melanosome", "melanoma", "pigment-biosynthetic process", "Epidermis development", "Ras-signaling pathway", "Wnt-signaling pathway", "response to UV light", and "tyrosine metabolism", involved in pigment synthesis and regulation in purple sea cucumbers. The large number of differentially expressed proteins identified here should be highly useful in further elucidating the mechanisms underlying pigmentation in sea cucumbers. Furthermore, these results may also provide the base for further identification of proteins involved in resistance mechanisms against melanoma, albinism, UV damage, and other diseases in sea cucumbers.

Electrochemical sensor for rapid determination of fibroblast growth factor receptor 4 in raw cancer cell lysates

The first electrochemical immunosensor for the determination of fibroblast growth factor receptor 4 (FGFR4) biomarker is reported in this work. The biosensor involves a sandwich configuration with covalent immobilization of a specific capture antibody onto activated carboxylic-modified magnetic microcarriers (HOOC-MBs) and amperometric detection at disposable carbon screen-printed electrodes (SPCEs). The biosensor exhibits a great analytical performance regarding selectivity for the target protein and a low LOD of 48.2 pg mL^-1. The electrochemical platform was successfully applied for the determination of FGFR4 in different cancer cell lysates without any apparent matrix effect after a simple sample dilution and using only 2.5 μg of the raw lysate. Comparison of the results with those provided by a commercial ELISA kit shows competitive advantages by using the developed immunosensor in terms of simplicity, analysis time, and portability and cost-affordability of the required instrumentation for the accurate determination of FGFR4 in cell lysates.

Inhibition of the fibroblast growth factor receptor (FGFR) pathway: the current landscape and barriers to clinical application

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) is a tyrosine kinase signaling pathway that has a fundamental role in many biologic processes including embryonic development, tissue regeneration, and angiogenesis. Increasing evidence indicates that this pathway plays a critical role in oncogenesis via gene amplification, activating mutations, or translocation in tumors of various histologies. With multiplex sequencing technology, the detection of FGFR aberrations has become more common and is tied to cancer cell proliferation, resistance to anticancer therapies, and neoangiogenesis. Inhibition of FGFR signaling appears promising in preclinical studies, suggesting a pathway of clinical interest in the development of targeted therapy. Phase I trials have demonstrated a manageable toxicity profile. Currently, there are multiple FGFR inhibitors under study with many non-selective (multi-kinase) inhibitors demonstrating limited clinical responses. As we progress from the first generation of non-selective drugs to the second generation of selective FGFR inhibitors, it is clear that FGFR aberrations do not behave uniformly across cancer types; thus, a deeper understanding of biomarker strategies is undoubtedly warranted. This review aims to consolidate data from recent clinical trials with a focus on selective FGFR inhibitors. As Phase II clinical trials emerge, concentration on patient selection as it pertains to predicting response to therapy, feasible methods for overcoming toxicity, and the likelihood of combination therapies should be utilized. We will also discuss qualities that may be desirable in future generations of FGFR inhibitors, with the hope that overcoming these current barriers will expedite the availability of this novel class of medications.

Fibroblast Growth Factor Receptor Family Members as Prognostic Biomarkers in Head and Neck Squamous Cell Carcinoma: A Systematic Review

BACKGROUND

Since head and neck cancer is characterized by poor survival rates, there is a demand for novel therapeutic targets and prognostic biomarkers. An upcoming therapeutic target is the fibroblast growth factor receptor (FGFR) family. However, their prognostic role in head and neck cancer remains unclear.

OBJECTIVE

To systematically review current evidence on the prognostic value of FGFR family members in head and neck squamous cell carcinoma (HNSCC).

METHODS

A systematic search of PubMed, Embase, and the Cochrane Library was performed for publications up to 14 May 2014. Two reviewers screened all articles and included prognostic studies on the molecular biomarkers FGFR1-5 in any type of HNSCC. Relevant studies were assessed on risk of bias using the Quality in Prognostic Studies (QUIPS) tool. Data on FGFR aberrations and survival outcome were extracted from relevant studies. The prognostic value of FGFR aberrations was compared among studies.

RESULTS

The initial search yielded 1568 publications of which 12 fulfilled the inclusion criteria. Four studies reported FGFR1 gene amplification (9.3-17.4 %) and FGFR1 protein overexpression (11.8 %) in HNSCC. FGFR1 protein expression by cancer-associated fibroblasts correlated with poor survival outcome in one study (p < 0.01). Eight studies reported high rates of FGFR4 Gly388Arg polymorphisms (32.5-54.2 %) and FGFR4 protein overexpression (16-35 %), with varying correlations with survival. So far, no studies assessed the prognostic role of FGFR2, FGFR3, or FGFR5 in HNSCC.

LIMITATIONS

Significant risk of bias has been identified among included studies. Therefore, cautious interpretation of the results is recommended.

CONCLUSION

In conclusion, evidence was found for prognostic value of FGFR1 expression in cancer-associated fibroblasts in HNSCC. Prognostic evidence on the other FGFR family members in HNSCC is limited and conflicting. This emphasizes the need for future well-conducted prognostic studies.

Predictors of chemotherapy efficacy in non-small-cell lung cancer: a challenging landscape

BACKGROUND

Conventional cytotoxic chemotherapy (CCC) is the backbone of non-small-cell lung cancer (NSCLC) treatment since decades and still represents a key element of the therapeutic armamentarium. Contrary to molecularly targeted therapies and immune therapies, for which predictive biomarkers of activity have been actively looked for and developed in parallel to the drug development process ('companion biomarkers'), no patient selection biomarker is currently available for CCC, precluding customizing treatment.

MATERIALS AND METHODS

We reviewed preclinical and clinical studies that assessed potential predictive biomarkers of CCC used in NSCLC (platinum, antimetabolites, topoisomerase inhibitors, and spindle poisons). Biomarker evaluation method, analytical validity, and robustness are described and challenged for each biomarker.

RESULTS

The best-validated predictive biomarkers for efficacy are currently ERCC1, RRM1, and TS for platinum agents, gemcitabine and pemetrexed, respectively. Other potential biomarkers include hENT1 for gemcitabine, class III β-tubulin for spindle poisons, TOP2A expression and CEP17 duplication (mostly studied for predicting anthracyclines efficacy) whose applicability concerning etoposide would deserve further evaluation. However, none of these biomarkers has till now been validated prospectively in an appropriately designed and powered randomised trial, and none of them is currently ready for implementation in routine clinical practice.

CONCLUSION

The search for predictive biomarkers to CCC has been proven challenging. If a plethora of biomarkers have been evaluated either in the preclinical or in the clinical setting, none of them is ready for clinical implementation yet. Considering that most mechanisms of resistance or sensitivity to CCC are multifactorial, a combinatorial approach might be relevant and further efforts are required.

Fibroblast growth factor receptor signaling in hereditary and neoplastic disease: biologic and clinical implications

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are transmembrane growth factor receptors with wide tissue distribution. FGF/FGFR signaling is involved in neoplastic behavior and also development, differentiation, growth, and survival. FGFR germline mutations (activating) can cause skeletal disorders, primarily dwarfism (generally mutations in FGFR3), and craniofacial malformation syndromes (usually mutations in FGFR1 and FGFR2); intriguingly, some of these activating FGFR mutations are also seen in human cancers. FGF/FGFR aberrations reported in cancers are mainly thought to be gain-of-function changes, and several cancers have high frequencies of FGFR alterations, including breast, bladder, or squamous cell carcinomas (lung and head and neck). FGF ligand aberrations (predominantly gene amplifications) are also frequently seen in cancers, in contrast to hereditary syndromes. There are several pharmacologic agents that have been or are being developed for inhibition of FGFR/FGF signaling. These include both highly selective inhibitors as well as multi-kinase inhibitors. Of note, only four agents (ponatinib, pazopanib, regorafenib, and recently lenvatinib) are FDA-approved for use in cancer, although the approval was not based on their activity against FGFR. Perturbations in the FGFR/FGF signaling are present in both inherited and malignant diseases. The development of potent inhibitors targeting FGF/FGFR may provide new tools against disorders caused by FGF/FGFR alterations.

Genomic diversity of colorectal cancer: Changing landscape and emerging targets

Improvements in screening and preventive measures have led to an increased detection of early stage colorectal cancers (CRC) where patients undergo treatment with a curative intent. Despite these efforts, a high proportion of patients are diagnosed with advanced stage disease that is associated with poor outcomes, as CRC remains one of the leading causes of cancer-related deaths in the world. The development of next generation sequencing and collaborative multi-institutional efforts to characterize the cancer genome has afforded us with a comprehensive assessment of the genomic makeup present in CRC. This knowledge has translated into understanding the prognostic role of various tumor somatic variants in this disease. Additionally, the awareness of the genomic alterations present in CRC has resulted in an improvement in patient outcomes, largely due to better selection of personalized therapies based on an individual’s tumor genomic makeup. The benefit of various treatments is often limited, where recent studies assessing the genomic diversity in CRC have identified the development of secondary tumor somatic variants that likely contribute to acquired treatment resistance. These studies have begun to alter the landscape of treatment for CRC that include investigating novel targeted therapies, assessing the role of immunotherapy and prospective, dynamic assessment of changes in tumor genomic alterations that occur during the treatment of CRC.

Cancer drug resistance: redox resetting renders a way

Disruption of redox homeostasis is a crucial factor in the development of drug resistance, which is a major problem facing current cancer treatment. Compared with normal cells, tumor cells generally exhibit higher levels of reactive oxygen species (ROS), which can promote tumor progression and development. Upon drug treatment, some tumor cells can undergo a process of 'Redox Resetting' to acquire a new redox balance with higher levels of ROS accumulation and stronger antioxidant systems. Evidence has accumulated showing that the 'Redox Resetting' enables cancer cells to become resistant to anticancer drugs by multiple mechanisms, including increased rates of drug efflux, altered drug metabolism and drug targets, activated prosurvival pathways and inefficient induction of cell death. In this article, we provide insight into the role of 'Redox Resetting' on the emergence of drug resistance that may contribute to pharmacological modulation of resistance.

Deguelin-induced blockade of PI3K/protein kinase B/MAP kinase signaling in zebrafish and breast cancer cell lines is mediated by down-regulation of fibroblast growth factor receptor 4 activity

Deguelin, a natural component derived from leguminous plants, has been used as pesticide in some regions. Accumulating evidence show that deguelin has promising chemopreventive and therapeutic activities against cancer cells. This study shows that low concentrations of deguelin can lead to significant delay in zebrafish embryonic development through growth inhibition and induction of apoptosis. Furthermore, we identified fibroblast growth factor receptor 4 (FGFR4) as the putative target of deguelin. The candidate was initially identified by a microarray approach and then validated through in vitro experiments using hormone‐responsive (MCF‐7) and nonresponsive (MDA‐MB‐231) human breast cancer cell lines. The results show that deguelin suppressed cell proliferation and induced apoptosis in both cancer cell lines, but not in Hs 578Bst cells, by blocking PI3K/AKT and mitogen‐activated protein kinases (MAPK) signaling. The FGFR4 mRNA and protein level also diminished in a dose‐dependent manner. Interestingly, we found that forced FGFR4 overexpression attenuated deguelin‐induced proliferative suppression and apoptotic cell death in both zebrafish and MCF‐7 cell lines, p‐AKT and p‐ERK levels were restored upon FGFR4 overexpression. Taken together, our results strongly suggest that deguelin inhibition of PI3K/AKT and MAPK signaling in zebrafish and breast cancer cell lines is partially mediated through down‐regulation of FGFR4 activity.

Targeting FGF receptors in colorectal cancer: from bench side to bed side

Successful management of advanced colorectal cancer has been a challenging job for practicing oncologists as well as a priority for the oncology research community. The better understanding of the underlying patho-biology and critical pathway targets in this disease has contributed to major developments in that direction. In this review, we will revise the different biological and clinical aspects related to the use of FGFR pathway-targeted therapies in advanced colorectal cancer with particular focus on future perspectives in that regard.

Silencing of FGFR4 could influence the biological features of gastric cancer cells and its therapeutic value in gastric cancer

To clarify the role of fibroblast growth factor receptor 4 (FGFR4) in gastric cancer (GC) and explore the therapeutic value of BGJ398 targeted to FGFR4. We constructed lentivirus vectors to stably knockdown FGFR4 expression in GC cells. Function assays in vitro and in vivo, treated with 5-fluorouracil (5-Fu) and BGJ398, were performed to study the change of biological behaviors of GC cells and related mechanism. The proliferation and invasive ability of HGC27 and MKN45 significantly decreased while the apoptosis rate of GC cells obviously increased in shRNA group (P < 0.05). The expressions of Bcl-xl, FLIP, PCNA, vimentin, p-erk, and p-STAT3 significantly reduced while the expressions of caspase-3 and E-cadherin markly enhanced in shRNA group. The proliferation abilities of GC cells were more significantly inhibited by the combination of BGJ398 and 5-Fu in shRNA group (P < 0.05). Compared to negative control (NC), the single and combination of 5-Fu and BGJ398 all significantly increased the apoptosis rate of GC cells, especially in the combination group (P < 0.01). The single and combination of 5-Fu and BGJ398 decreased the expressions of PCNA, Bcl-xl, and FLIP while increased the expression of caspase-3 in GC cells, especially in shRNA groups. Furthermore, knockdown of FGFR4 expression might prevent the growth of GC in vivo. Silencing of FGFR4 expression could weaken the invasive ability, increase the apoptosis rate, and decrease the proliferation ability of GC cells in vitro and in vivo. Furthermore, the combination of 5-Fu and BGJ398 had synergy in inhibiting the proliferation ability and increasing apoptosis rate of GC cells, directing a new target drug in GC.

Fibroblast growth factor receptor 4 protein expression and clinicopathological features in gastric cancer

AIM: To investigate fibroblast growth factor receptor 4 (FGFR4) protein expression in Chinese patients with resectable gastric cancer (GC) and the association with clinicopathological characteristics and survival.

METHODS: One hundred and seventy-five GC patients who underwent curative surgical procedures were enrolled in this study. The protein expression of FGFR4 in formalin-fixed, paraffin-embedded (FFPE) GC tissues was determined by immunohistochemical (IHC) analysis. Patient clinicopathological data and survival information were also collected and χ² statistical analysis was performed to analyze FGFR4 protein expression in the subgroups with differing clinicopathological characteristics including; gender, age, tumor location, differentiation, tumor-node-metastasis stage, macroscopic type, depth of invasion, lymph node metastases, distant metastasis, neural invasion and vascular invasion. Furthermore, some common molecular markers of GC in our cancer center, including p53, p27, topoisomerase IIα (Topo IIα) were also determined by IHC and their association with FGFR4 protein expression evaluated. The probability of survival for different subgroups with different clinicopathological characteristics was calculated using the Kaplan-Meier method and survival curves plotted using the log rank test.

RESULTS: Seventy seven cases (44%) were found to have high expression of FGFR4 protein. Significantly different FGFR4 expression was observed between gastric cancers with differing expression of Topo IIα (log rank χ² = 9.4760, P = 0.0236). No significant differences were observed between subgroups defined by any of the other clinicopathological characteristics. The median survival time of the FGFR4 high expression (77 cases) and low expression groups (98 cases) was 27 mo and 39 mo, respectively. The five-year survival rates and median survival times of gastric cancers with high FGFR4 expression were worse than those with low expression (30.8% vs 39.2%, 27 mo vs 39 mo), respectively, however, no significant difference was observed in survival time (log rank χ² = 1.0477, P = 0.3060). Survival analysis revealed that high expression of FGFR4 was a predictor of poor outcome in GC patients if the tumor was small (less than or equal to 3 cm in size) (log rank χ² = 5.5033, P = 0.0190), well differentiated (log rank χ² = 7.9757, P = 0.0047), and of T1 or T2 stage invasion depth (log rank χ² = 4.8827, P = 0.0271).

CONCLUSION: Our results suggest that high tumor expression of FGFR4 protein is not an independent risk factor for GC cancer initiation, but is a useful prognostic marker for GC patients when the tumor is relatively small, well differentiated, or in the early stages of invasion.

Structural insights into FGFR kinase isoform selectivity: diverse binding modes of AZD4547 and ponatinib in complex with FGFR1 and FGFR4

The fibroblast growth factor receptor (FGFR) family of receptor tyrosine kinases has been implicated in a wide variety of cancers. Despite a high level of sequence homology in the ATP-binding site, the majority of reported inhibitors are selective for the FGFR1-3 isoforms and display much reduced potency toward FGFR4, an exception being the Bcr-Abl inhibitor ponatinib. Here we present the crystal structure of the FGFR4 kinase domain and show that both FGFR1 and FGFR4 kinase domains in complex with ponatinib adopt a DFG-out activation loop conformation. Comparison with the structure of FGFR1 in complex with the candidate drug AZD4547, combined with kinetic characterization of the binding of ponatinib and AZD4547 to FGFR1 and FGFR4, sheds light on the observed differences in selectivity profiles and provides a rationale for developing FGFR4-selective inhibitors.

Development of covalent inhibitors that can overcome resistance to first-generation FGFR kinase inhibitors

The human FGF receptors (FGFRs) play critical roles in various human cancers, and several FGFR inhibitors are currently under clinical investigation. Resistance usually results from selection for mutant kinases that are impervious to the action of the drug or from up-regulation of compensatory signaling pathways. Preclinical studies have demonstrated that resistance to FGFR inhibitors can be acquired through mutations in the FGFR gatekeeper residue, as clinically observed for FGFR4 in embryonal rhabdomyosarcoma and neuroendocrine breast carcinomas. Here we report on the use of a structure-based drug design to develop two selective, next-generation covalent FGFR inhibitors, the FGFR irreversible inhibitors 2 (FIIN-2) and 3 (FIIN-3). To our knowledge, FIIN-2 and FIIN-3 are the first inhibitors that can potently inhibit the proliferation of cells dependent upon the gatekeeper mutants of FGFR1 or FGFR2, which confer resistance to first-generation clinical FGFR inhibitors such as NVP-BGJ398 and AZD4547. Because of the conformational flexibility of the reactive acrylamide substituent, FIIN-3 has the unprecedented ability to inhibit both the EGF receptor (EGFR) and FGFR covalently by targeting two distinct cysteine residues. We report the cocrystal structure of FGFR4 with FIIN-2, which unexpectedly exhibits a "DFG-out" covalent binding mode. The structural basis for dual FGFR and EGFR targeting by FIIN3 also is illustrated by crystal structures of FIIN-3 bound with FGFR4 V550L and EGFR L858R. These results have important implications for the design of covalent FGFR inhibitors that can overcome clinical resistance and provide the first example, to our knowledge, of a kinase inhibitor that covalently targets cysteines located in different positions within the ATP-binding pocket.

Regulation of metastasis of pediatric multiple myeloma by MMP13

The molecular mechanism underlying metastasis of pediatric multiple myeloma (MM) remains elusive. Here, we showed that the levels of MMP13 are significantly higher in MM from young patients than those from adult patients. Moreover, a strong correlation of the MMP13 and phosphorylated fibroblast growth factor receptor 4 (FGFR4) levels was detected in MM from young patients. To prove a causal link between activation of fibroblast growth factor receptors (FGFR) signaling pathway and MMP13 expression, we used a human MM line, RPMI-8226 (8226), to study the underlying molecular basis. We found that FGF1-induced FGFR4 phosphorylation in 8,226 cells resulted in significant activation of MMP13, and consequently, an increase in cancer invasiveness. FGFR4 inhibition in 8,226 cells abolished FGF1-stimulated MMP13 expression, suggesting that activation of FGFR signaling pathway in MM may promote cancer metastasis by inducing MMP13 expression. To define the signaling cascades downstream of FGFR4 activation for MMP13 activation, we applied specific inhibitors for PI3K, Jun N-terminal kinase (JNK), and ERK/MAPK, respectively, to the FGF1-stimulated 8,226 cells. We found that only inhibition of ERK1/2 significantly decreased the activation of MMP13 in response to FGF stimulation, suggesting that activation of FGFR signaling may activate ERK/MAPK, rather than JNK or PI3K pathway to activate MMP13 expression in 8,226 cells. Our study thus highlights FGFR4 signaling pathway and MMP13 as novel therapeutic targets for MM.