PhD project (Bou Antoun Nauf): 'FGFR Inhibitor Resistance in Cervical Cancer: Characterizing Novel Resistant Cell Line Models and Mechanistic Insights

Cervical cancer remains the fourth most common cancer among women worldwide, with many cases diagnosed at advanced stages and limited treatment options for recurrent disease. Although fibroblast growth factor (FGF) signalling is essential for normal cell growth and repair, its abnormal activation through fibroblast growth factor receptors (FGFRs) contributes to tumour progression, metastasis, and therapy resistance. Despite the clinical potential of FGFR inhibitors, their effectiveness is often compromised by the development of drug resistance.

This project aimed to investigate the molecular mechanisms underlying acquired resistance to FGFR-targeted therapy in cervical cancer and to establish robust experimental models to study this phenomenon. Three human cervical cancer cell lines (HeLa, CaSki, and SiHa) were developed with acquired resistance to the FGFR/EGFR inhibitor PD173074. Compared with their parental counterparts, the drug-resistant (DR) cell lines showed overexpression and nuclear localisation of FGFR1, FGFR2, FGF2, FGF4, and FGF7, as well as increased cell proliferation, migration, and survival, indicating a more aggressive phenotype.

Transcriptomic profiling of resistant and wild-type cell lines identified key differentially expressed genes (DEGs), including downregulation of PHLDA1 and upregulation of PLCB4, both associated with metastatic behaviour. Network analysis highlighted integrin α2 (ITGA2) as a central regulator, with resistant cells displaying increased cytoplasmic ITGA2, loss of cell junction localisation, and activation of focal adhesion kinase (FAK) signalling. Persistent phosphorylation of S6 ribosomal protein (p-S6) in resistant cells—unaffected by inhibition of FGFR, FAK, or mTORC1—suggests an alternative AKT-independent mechanism of mTOR activation.

Together, these findings indicate that FGFR inhibitor resistance in cervical cancer involves ITGA2–FAK signalling and sustained mTOR activation. The newly developed resistant cell lines serve as valuable models for further exploration of resistance pathways and for testing combination therapeutic strategies aimed at overcoming FGFR-targeted drug resistance.

Cervical cancer is one of the most common cancers in women worldwide, and many patients with advanced disease eventually stop responding to treatment. This project looked at how cervical cancer cells become resistant to drugs that block a key growth system in the body called the fibroblast growth factor (FGF) pathway.

We created new laboratory models of cervical cancer cells that no longer responded to FGFR-targeting drugs. These resistant cells grew and spread faster and were harder to kill than normal cells. By analysing changes in genes and proteins, the study found that resistance was linked to increased activity of two molecules — integrin α2 (ITGA2) and focal adhesion kinase (FAK) — which help cancer cells move and survive. The cells also activated a growth pathway (mTOR) that stayed active even when FGFR was blocked.

These findings reveal new ways cervical cancer cells escape treatment and suggest that combining FGFR inhibitors with drugs targeting ITGA2-FAK or mTOR could make therapies more effective.

Three cervical cancer cell lines (HeLa, CaSki, and SiHa) were successfully developed with acquired resistance to the FGFR/EGFR inhibitor PD173074.

The drug-resistant (DR) cell lines displayed a more aggressive phenotype, with increased proliferation, enhanced migration, and reduced apoptosis compared with parental lines.

FGFR1, FGFR2, FGF2, FGF4, and FGF7 were overexpressed and localised to the nucleus in resistant cells.

Transcriptomic profiling identified multiple differentially expressed genes (DEGs) between resistant and wild-type lines, including:

Downregulation of PHLDA1 (associated with reduced apoptosis).

Upregulation of PLCB4 (linked to metastatic potential).

Protein interaction network analysis identified integrin α2 (ITGA2) as a central regulatory node involved in resistance.

Resistant cells exhibited cytoplasmic redistribution of ITGA2, loss from cell junctions, and activation of focal adhesion kinase (FAK) signalling.

Elevated phosphorylation of S6 ribosomal protein (p-S6) persisted in resistant cells, indicating activation of the mTOR pathway independent of AKT.

Inhibition of FGFR, FAK, or mTORC1 failed to suppress p-S6 activity, suggesting alternative survival signalling mechanisms sustain resistance.

The data support a model in which ITGA2–FAK signalling and AKT-independent mTOR activation drive resistance to FGFR inhibitors in cervical cancer.

The newly developed resistant cervical cancer cell lines provide a valuable experimental model for dissecting resistance mechanisms and for testing combinatorial therapeutic strategies targeting FAK and mTOR pathways.