Open Access

ARTICLE

Pinin Modulation Restores Chemosensitivity in SW620 and HCT-116 Colon Cancer Cells

Molli Alice¹, Buonvicino Daniela¹, Mattei Gianluca^1,2, Bonacchi Leonardo¹, Scuffi Irene¹, Calcagno Sara³, Isoldi Giulia³, Schiavone Nicola³, De Logu Francesco¹, Magi Alberto⁴, Lulli Matteo^3,#, Parenti Astrid^1,#, Lapucci Andrea^1,#,*
1 Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
2 Unit of Translational and Precision Medicine, Meyer Children’s Hospital IRCCS, Florence, Italy
3 Department of Experimental and Clinical Biomedical Sciences, “Mario Serio” University of Florence, Florence, Italy
4 Department of Information Engineering, University of Florence, Florence, Italy
* Corresponding Author: Lapucci Andrea. Email:
# These authors contributed equally as last authors

Oncology Research https://doi.org/10.32604/or.2026.084313

Received 20 April 2026; Accepted 17 June 2026; Published online 25 August 2026

Abstract

Objectives: Colorectal cancer (CRC) remains a leading cause of cancer-related mortality, largely due to the emergence of resistance to standard chemotherapeutic regimens. The identification of molecular determinants of chemoresistance is therefore critical to improve patient stratification and therapeutic efficacy. Here, we investigate the functional role of Pinin (PNN), a multifunctional protein involved in RNA processing and gene regulation, in mediating chemoresistance in CRC. Methods: SW620 and HCT-116 colorectal cancer cells were used to investigate the functional role of PNN. Pnn expression was silenced by siRNA and lentiviral shRNA approaches. Cell sensitivity to 5-fluorouracil and oxaliplatin was evaluated by MTT assay, while apoptosis was assessed by Annexin V/7-AAD flow cytometry. Migration, invasion, and clonogenic capacity were analyzed using wound-healing, modified Boyden chamber, and colony formation assays. Metabolic reprogramming following Pnn depletion was characterized using Seahorse extracellular flux analysis. Transcriptomic alterations were investigated by Nanopore RNA sequencing, followed by differential gene expression, bioinformatic, and gene set enrichment analyses. Results: Pnn silencing significantly enhanced sensitivity to 5-fluorouracil and oxaliplatin in SW620 cells, as demonstrated by reduced cell viability, decreased IC₅₀ values, and increased apoptotic responses. Transcriptomic profiling revealed extensive gene expression reprogramming, affecting pathways related to cell cycle progression, DNA damage response, and stress signaling. To corroborate these findings, Pnn-silenced HCT-116 cells were used to confirm the observed cytotoxic effects and independently validate selected differentially expressed genes identified by RNA-seq in SW620 cells. Notably, Pnn depletion induced a marked impairment of mitochondrial oxidative phosphorylation without compensatory glycolytic activation, indicating reduced metabolic flexibility under stress conditions. Functionally, Pnn silencing also decreased clonogenic capacity and invasive behavior. Conclusion: Collectively, these findings identify Pnn as a key regulator of chemoresistance and reveal its involvement in transcriptional control, metabolic adaptation, and stress response. Targeting PNN-related pathways may represent a promising therapeutic strategy to restore chemosensitivity and improve outcomes in colorectal cancer, although further validation is required.

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Keywords

Colorectal cancer; chemoresistance; RNA processing; oxaliplatin; 5-fluorouracil; metabolic reprogramming

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