Sjoblom, M. | bioRxiv Science

bioRxiv2025

Irinotecan induces intestinal atrophy and compromises duodenal motility and mucosal permeability: in vivo and in vitro evaluations

PurposeIntestinal toxicity is a significant adverse effect of chemotherapy, with no effective treatments currently available. This study aimed to evaluate the effects of irinotecan (IRT) on; (i) duodenal motility and mucosal barrier function, (ii) histopathological changes along the small intestine and colon, and (iii) faecal water content, to better understand IRT-induced intestinal toxicity, and to support future treatment strategies to minimize these effects. MethodsSprague Dawley rats were anaesthetized with thiobarbiturate, and a 30-mm long segment of the proximal duodenum with an intact blood supply was perfused in situ. The effects of IRT on duodenal motility and blood-to-lumen clearance of 3H-mannitol were investigated. In separate experiments, intestinal toxicity was induced in rats by intravenous (i.v.) dosing with IRT. After 72 h post IRT administration, the rats were sacrificed and the small intestine and the colon were excised for histological analysis. Fecal water contents and change in body weight were also measured. In addition, effects of IRT on cell viability were evaluated via Caco-2 cell culture, IRT treatment, and resazurin reduction assays. ResultIntravenous dosing of IRT (60 mg/kg) significantly induced robust and sustained increase in both duodenal motility (+277%) and in mucosal paracellular permeability (+85%). Moreover, IRT in doses of 180 mg/kg and 200 mg/kg (i.p.), induced similar reduction in villus length evaluated 72 h post administration; in duodenum (-52% and -45%, respectively) and jejunum (-37% and -33%), but was without effects in ileum. IRT induced increases in jejunal crypt depth (+48% and +41%), but did not significantly influence the crypt depth in duodenum, ileum or colon. IRT induced increases in fecal water content by +19% and +16%, respectively, and caused significant body weight reductions by 10% and 13%, respectively. IRT exposing of Caco-2 cells resulted in a significant decrease in viability, and a resulting IC50 value of 1289 M. ConclusionsOur novel results show that IRT highly increases duodenal motility and impair mucosal barrier function. In addition, IRT induces diarrhoea, and demonstrates histopathological in the proximal small intestine. These findings contribute to the basic physiological understanding, and provide potentially new innovations for treatment of IRT-induced intestinal toxicity.

cancer biology↗

bioRxiv2025

A comparative study of the chemotoxic effects of idarubicin and doxorubicin in a chemically-induced in vivo mouse model and in vitro models for hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a significant clinical challenge, with limited therapeutic options. Anthracyclines such as doxorubicin (DOX) and idarubicin (IDA) are commonly used in cancer treatment but have shown variable efficacy and side effects in HCC. This study aimed to compare the cytotoxic effects of DOX and IDA on HCC in both in vivo and in vitro models, assess their impact on the tumor and its microenvironment, as well as identify potential adverse effects. In vivo, both DOX and IDA treatments led to a significant reduction in body weight and spleen-to-body weight ratio, with IDA showing a more pronounced effect. However, neither treatment significantly affected intestinal morphology, compared to untreated mice with HCC. None of the treatments had a significant impact on macroscopic or microscopic tumor burden. Notably, DOX and IDA treatments resulted in a significant reduction in collagen deposition and liver fibrosis. DOX reduced hepatic stellate cell (HSC) activation, despite having no significant impact on the expression levels of fibrotic markers TGF-{beta} and CTGF. In contrast, IDA not only increased HSC activation but also upregulated TGF-{beta} and CTGF expression in both tumor and peritumoral tissues. Molecular analysis further revealed that DOX and IDA treatments increased mRNA levels of ER-stress and proliferation markers in non-tumor tissues, with significant findings within the PERK pathway. IDA, in particular, induced higher ATF4 expression in hepatocytes and enhanced macrophage recruitment in tissue sections. While DOX and IDA exhibit limited effectiveness in reducing HCC tumor burden in vivo, the in vitro analyses showed that DOX and IDA demonstrated strong, concentration-dependent cytotoxicity, significantly reducing cell viability in all tested HCC cell lines. Increasing complexity of the in vitro models, by culturing in 3D and adding HSCs, decreased the sensitivity to the anthracyclines. This, along with the effects on liver fibrosis, stellate cell activation and inflammation seen in vivo, may be the result of the significant contribution of the tumor microenvironment in mediating drug response. The differential expression of ER-stress and proliferation markers, particularly in the PERK pathway, further highlights the complexity of the tumor microenvironments influence on treatment outcomes. More research into these molecular responses and underlying mechanisms is needed to provide insights into improving therapeutic strategies for HCC.

cancer biology↗