Short-Duration HIPEC-Mimetic Mithramycin A Exposure Induces Durable Transcriptional Remodeling Involving Chromatin Regulatory Networks in Colorectal Cancer Models

Hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal peritoneal metastases relies primarily on DNA-damaging agents whose efficacy depends on sustained cytotoxic exposure. Whether brief treatment can induce durable transcriptional remodeling remains unclear. Mithramycin A (MA) is a GC-rich DNA-binding agent with transcriptional regulatory activity involving chromatin-associated pathways. Here, we investigated the molecular and functional consequences of a single 90-min HIPEC-mimetic MA exposure in colorectal cancer models. RNA sequencing revealed extensive and coordinated transcriptional remodeling, affecting a substantial fraction of expressed genes and producing a response qualitatively distinct from mitomycin C. MA selectively suppressed key chromatin-associated regulatory factors, including DNMT1, JARID2, and HDAC4, while coordinately activating canonical cyclin-dependent kinase inhibitors CDKN1A, CDKN1C, and CDKN2C. Gene set enrichment analysis demonstrated enrichment of G2/M checkpoint pathways and suppression of oncogenic gene networks. These molecular changes translated into sustained inhibition of clonogenic growth and activation of caspase-dependent apoptosis following drug washout, with hyperthermia potentiating apoptotic signaling. Collectively, these findings indicate that brief MA exposure induces selective modulation of chromatin regulators and durable transcriptional reorganization, supporting modulation of chromatin regulatory networks as a potential therapeutic strategy for HIPEC-based colorectal cancer therapy.