Combination of dual JAK/HDAC inhibitor with regorafenib synergistically reduces tumor growth, metastasis, and regorafenib-induced toxicity in colorectal cancer

J Exp Clin Cancer Res. 2024 Jul 11;43(1):192. doi: 10.1186/s13046-024-03106-8.

Abstract

Background: Treatment with regorafenib, a multiple-kinase inhibitor, to manage metastatic colorectal cancers (mCRCs) shows a modest improvement in overall survival but is associated with severe toxicities. Thus, to reduce regorafenib-induced toxicity, we used regorafenib at low concentration along with a dual JAK/HDAC small-molecule inhibitor (JAK/HDACi) to leverage the advantages of both JAK and HDAC inhibition to enhance antitumor activity. The therapeutic efficacy and safety of the combination treatment was evaluated with CRC models.

Methods: The cytotoxicity of JAK/HDACi, regorafenib, and their combination were tested with normal colonic and CRC cells exhibiting various genetic backgrounds. Kinomic, ATAC-seq, RNA-seq, cell cycle, and apoptosis analyses were performed to evaluate the cellular functions/molecular alterations affected by the combination. Efficacy of the combination was assessed using patient-derived xenograft (PDX) and experimental metastasis models of CRC. To evaluate the interplay between tumor, its microenvironment, and modulation of immune response, MC38 syngeneic mice were utilized.

Results: The combination therapy decreased cell viability; phosphorylation of JAKs, STAT3, EGFR, and other key kinases; and inhibited deacetylation of histone H3K9, H4K8, and alpha tubulin proteins. It induced cell cycle arrest at G0-G1 phase and apoptosis of CRC cells. Whole transcriptomic analysis showed that combination treatment modulated molecules involved in apoptosis, extracellular matrix-receptor interaction, and focal adhesion pathways. It synergistically reduces PDX tumor growth and experimental metastasis, and, in a syngeneic mouse model, the treatment enhances the antitumor immune response as evidenced by higher infiltration of CD45 and cytotoxic cells. Pharmacokinetic studies showed that combination increased the bioavailability of regorafenib.

Conclusions: The combination treatment was more effective than with regorafenib or JAK/HDACi alone, and had minimal toxicity. A clinical trial to evaluate this combination for treatment of mCRCs is warranted.

Keywords: Colorectal cancer; Combination therapy; JAK/HDACi; Regorafenib; Toxicity.

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Apoptosis / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Colorectal Neoplasms* / drug therapy
  • Colorectal Neoplasms* / metabolism
  • Colorectal Neoplasms* / pathology
  • Drug Synergism
  • Female
  • Histone Deacetylase Inhibitors* / administration & dosage
  • Histone Deacetylase Inhibitors* / pharmacology
  • Histone Deacetylase Inhibitors* / therapeutic use
  • Humans
  • Janus Kinase Inhibitors / administration & dosage
  • Janus Kinase Inhibitors / pharmacology
  • Janus Kinase Inhibitors / therapeutic use
  • Mice
  • Neoplasm Metastasis
  • Phenylurea Compounds* / administration & dosage
  • Phenylurea Compounds* / pharmacology
  • Pyridines* / administration & dosage
  • Pyridines* / pharmacology
  • Xenograft Model Antitumor Assays

Substances

  • regorafenib
  • Phenylurea Compounds
  • Pyridines
  • Histone Deacetylase Inhibitors
  • Janus Kinase Inhibitors