Ex-vivo tumor tissue culture systems are used as models to test specific anti-cancer drugs. Their main advantage is that they are closely comparable with the in vivo tumor in their host organism. We previously reported that precision-cut organotypic tissue slices of pancreatic ductal adenocarcinoma (PDAC) can be successfully cultured ex-vivo for at least 4 days. In order to study how culturing might affect transcription patterns, we now performed genome-wide transcriptome profiling of both baseline (0 h) and explanted tumors at daily intervals (24, 48 and 72 h) after start of culturing. The total-RNA from five samples of surgically resected human PDAC tumors at baseline and at different time points in culture was sequenced. Differential gene expression analysis of the whole transcriptome, testing 58,713 genes and over 206,000 transcripts, found that only a small number of genes showed significant changes in expression between baseline and cultured samples. The cultured tumor slices showed upregulation of a median of 12, 10 and 15 genes and downregulation of a median of 15, 12 and 25 genes at 24, 48 and 72 h in culture, respectively. One sample had morphologically increasing loss of tissue viability (range 0–18%). The vascular endothelial growth factor A (VEGFA) was significantly upregulated during the entire culture period in this case. Pathway over-representation analysis suggested that VEGFA together with the PTGS2 gene were upregulated at the same time as HIF-1-triggered cell apoptosis via NF-ĸB and the AP-1 activating factor was induced. Indeed, increased areas of apoptotic lesions were visible in this sample after 24 hours of culture. In conclusion, genome-wide transcriptome analysis supports that ex-vivo cultured tissue slices of PDAC may be a representative model of the original tumor. Transcriptome analysis was found to be a valuable complement to morphology for evaluation of ex-vivo cultures of PDAC.

The telomerase reverse transcriptase (TERT) gene rs2736100_C allele has recently been shown to be associated with an increased risk for myeloproliferative neoplasms (MPNs) among Caucasians. However, it is unknown if this association is present in other ethnical populations and whether rs2736100 allele frequencies mirror the incidence of MPNs in a population. Here we genotyped TERT rs2736100 variants in 126 Swedish and 101 Chinese MPN patients and their age-, sex-, and ethnically-matched healthy controls. Healthy Chinese adults had a higher frequency of the A allele and lower frequencies of the C allele compared to Swedish counterparts (57.4 vs 47.0 % for A, 42.6 vs 53.0 % for C, P = 0.006). Both Swedish and Chinese patients harbored significantly higher C allele frequency than their controls (62.7 vs 53.0 % and 57.4 vs 42.6 % for Swedish and Chinese, respectively, P = 0.004). Swedes and Chinese bearing the CC genotype had a significantly increased risk of MPN compared to AA carriers (OR = 2.47; 95 % CI: 1.33–4.57, P = 0.003, for Swedes, and OR = 3.45; 95 % CI: 1.52–7.85, P = 0.005, for Chinese). Further analyses showed that rs2736100_CC was associated with robustly enhanced risk in males only (CC vs AA, OR = 5.11; 95 % CI: 2.19–11.92, P < 0.0001). The CC-carrying MPN patients exhibited significantly higher TERT expression than patients with the AC genotype. Collectively, the rs2736100_C is a risk allele for MPNs in Swedish and Chinese males, and the lower incidence of MPNs in the Chinese population is correlated with a lower rs2736100_C risk allele frequency.

Patient-derived tissue culture models are valuable tools to investigate drug effects and targeted treatment approaches. Resected tumor slices cultured ex vivo have recently gained interest in precision medicine, since they reflect the complex microenvironment of cancer tissue. In this study, we examined the treatment response to an internally developed ex vivo tissue culture model from pancreatic ductal adenocarcinoma (PDAC) and in vitro analysis. Seven PDAC tissues were cultured and subsequently treated with indole-3-pyruvic acid (IPA). IPA, which is known as an agonist of the aryl hydrocarbon receptor (AHR) pathway, has antioxidant properties. Genome-wide transcriptome sequencing analysis revealed activation of AHR pathway genes (CYP1A1 and CYP1B1, p ≤ 0.05). Additionally, significant upregulation of AHR repressor genes AHRR and TiPARP was also observed (p ≤ 0.05), which is indicative of the negative feedback loop activation of AHR pathway signaling. The overall transcriptomic response to IPA indicated that the tissues are biologically active and respond accordingly to exogenous treatment. Cell culture analysis confirmed the significant induction of selected AHR genes by IPA. A morphological examination of the paraffin-embedded formalin-fixed tissue did not show obvious signs of IPA treatment related to tumor cell damage. This study is a proof of concept that ex vivo patient-derived tissue models offer a valuable tool in precision medicine to monitor the effect of personalized treatments.

Pancreatic ductal adenocarcinoma (PDAC) remains a highly aggressive malignancy with limited treatment options. Targeting metabolic vulnerabilities and disrupting redox stress pathways has gained increasing attention as a potential therapeutic strategy. γ-Glutamyl-selenomethylselenocysteine (GGMSC) is a selenium-containing compound structurally related to seleno-L-methylselenocysteine (MSC), which has shown anticancer potential in preclinical models, although its molecular effects in PDAC are not well defined. In this study, we investigated the transcriptomic response to high-dose GGMSC in two PDAC cell lines, CAPAN-2 and HPAF-II. RNA sequencing and cytotoxicity assays revealed marked sensitivity to GGMSC in CAPAN-2 cells, associated with activation of oxidative stress and ferroptosis-related pathways, alongside downregulation of metabolic and cell cycle genes. Conversely, HPAF-II cells displayed limited transcriptional alterations and maintained proliferative and metabolic programs. These findings offer insights into the molecular mechanisms underlying GGMSC-induced transcriptional responses in PDAC and suggest potential avenues for future investigations of selenium-based therapies in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by profound therapy resistance, desmoplasia, and phenotypic plasticity. While sodium selenite is a redox-active compound with reported tumor-selective cytotoxicity, its impact on epithelial-mesenchymal transition (EMT) states in PDAC remains insufficiently defined. We investigated whether selenite modulates EMT-associated phenotypes in a dose- and context-dependent manner using complementary in vitro and patient-derived ex vivo models and linked marker shifts to histological tumor regression in PDAC tissue slices. Three PDAC cell lines spanning distinct baseline EMT states (PANC-1, HPAF-II, Capan-2) were profiled by quantitative immunofluorescence for a predefined epithelial (EpCAM, cytokeratin, E-cadherin) and mesenchymal-associated (AHNAK2, ITGAV, vimentin) protein panel, with or without TGF-β pretreatment. Ex vivo tissue slices from treatment-naïve, non-metastatic PDAC resections (n = 10) were cultured in a within-patient paired design (0 h, 24 h, 48 h controls; 5 or 15 µM selenite during the second 24 h). Histological tumor regression was scored by a blinded pancreatic pathologist (Evans; CAP), compartment-resolved marker expression was quantified by multiplex immunofluorescence, and paired RNA sequencing was performed in a subset of donors (n = 4). In vitro, responses were phenotype-contingent: the epithelial-biased HPAF-II and Capan-2 lines showed partial epithelial reinforcement and a consistent reduction of mesenchymal markers (particularly ITGAV, vimentin), whereas the mesenchymal-biased PANC-1 exhibited limited modulation. TGF-β pretreatment attenuated epithelial-promoting effects while suppression of mesenchymal markers was retained in a cell line-dependent manner. In ex vivo slices, selenite induced a dose-dependent improvement in histological tumor regression and increased the tumor-compartment epithelial-mesenchymal ratio at 15 µM, driven mainly by epithelial-marker upregulation, while mesenchymal markers showed no uniform suppression. At 15 µM, transcriptomics revealed a compact treatment response characterized by downregulation of basement-membrane/ECM modules without broad reversal across EMT gene sets; EMT scoring indicated heterogeneous shifts at 5 µM and a more consistent epithelial-leaning shift at 15 µM in most donors. Selenite was associated with reinforcement of epithelial features mainly in malignant PDAC compartments in a baseline-state-, dose-, and context-dependent manner, with higher-dose phenotypic shifts occurring alongside stronger histological tumor response in clinically proximal models. Not applicable.

Pancreatic ductal adenocarcinoma (PDAC) remains a highly aggressive malignancy with limited treatment options. Targeting metabolic vulnerabilities and disrupting redox stress pathways has gained increasing attention as a potential therapeutic strategy. γ-Glutamyl-selenomethylselenocysteine (GGMSC) is a selenium-containing compound structurally related to seleno-L-methylselenocysteine (MSC), has shown anticancer potential in preclinical models, although its molecular effects in PDAC are not well defined. In this study, we investigated the transcriptomic response to high-dose GGMSC in two PDAC cell lines, CAPAN-2 and HPAF-II. RNA sequencing and cytotoxicity assays revealed marked sensitivity to GGMSC in CAPAN-2 cells, associated with activation of oxidative stress and ferroptosis-related pathways, alongside downregulation of metabolic and cell cycle genes. Conversely, HPAF-II cells displayed limited transcriptional alterations and maintained proliferative and metabolic programs. These findings offer insights into the molecular mechanisms underlying GGMSC-induced transcriptional responses in PDAC and suggest potential avenues for future investigations of selenium-based therapies in pancreatic cancer.