Classification of Gemcitabine resistant Cholangiocarcinoma cell lines using synchrotron FTIR microspectroscopy

Cholangiocarcinoma (CCA), a cancer of bile duct epithelium, is a major health problem in Thailand especially in the northeast. Overall treatment outcomes have not shown much improvement because the disease is usually detected at an advanced stage and often shows chemotherapeutic resistance. High-throughput Fourier Transform Infrared (FTIR) microspectroscopy can be used for cell classification and has the potential to diagnose cancer and possibly predict chemo-response. This study was aimed to differentiate gemcitabine-sensitive and gemcitabine-resistant induction in two CCA cell lines (KKU-M139 and KKU-M214) and xenograft tissues using synchrotron-FTIR microspectroscopy. Partial Least Squares Discriminant Analysis (PLS-DA) could discriminate between chemo-sensitive and chemo-resistant cells in the FTIR fingerprint spectral region (1800–1000 cm^–1) with more than 90% sensitivity and specificity. The chemo-resistant and chemo-sensitive phenotypes were different in protein (amide I, amide II), lipids (carbonyl group and CH₃ deformation) and phosphodiester from nucleic acids. Additionally, spectra from xenograft tissues showed similar results to the cell line study with marked differences between chemo-resistant and chemo-sensitive CCA tissues, and PLS-DA could discriminate the chemotherapeutic response with 98% sensitivity and specificity. This is the first study to demonstrate the use of FTIR microspectroscopy to assess chemo-response both in vitro and in vivo.