Sublethal heat treatment enhances lactic acid uptake in macrophages via MCT1, leading to reduced paraspeckle formation and a subsequent decrease in macrophage pyroptosis

Introduction

Heat ablation is one of the key modalities in treating liver cancer, yet the residual cancer tissues suffering sublethal heat treatment possess a potential for increased malignancy. This study conducts a comprehensive analysis of cellular dynamics, metabolic shifts, and macrophage polarization within the tumor microenvironment following sublethal heat treatment.

Methods

We observed significant acidification in tumor cell supernatants, attributed to increased lactic acid production. The study focused on how this pH shift, crucial in tumor progression and resistance, influences macrophage polarization, especially towards the M2 phenotype known for tumor-promoting functions. We also examined the upregulation of MCT1 expression post sublethal heat treatment and its primary role in lactic acid transport.

Results

Notably, the study found minimal disparity in MCT1 expression between hepatocellular carcinoma patients and healthy liver tissues, highlighting the complexity of cancer biology. The research further revealed an intricate relationship between lactic acid, MCT1, and the inhibition of macrophage pyroptosis, offering significant insights for therapeutic strategies targeting the tumor immune environment. Post sublethal heat treatment, a reduction in paraspeckle under lactic acid exposure was observed, indicating diverse cellular impacts. Additionally, PKM2 was identified as a key molecule in this context, with decreased levels after sublethal heat treatment in the presence of lactic acid.

Discussion

Collectively, these findings illuminate the intertwined mechanisms of sublethal heat treatments, metabolic alterations, and immune modulation in the tumor milieu, providing a deeper understanding of the complex interplay in cancer biology and treatment.

Extended curettage and heat ablation for desmoplastic fibroma of the distal femur with a 12-year follow-up period: A case report

Desmoplastic fibroma is a particularly rare, benign but locally aggressive, primary bone tumor. Owing to previously published reports stating high recurrence rates following curettage, the recommended primary treatment for desmoplastic fibroma is a marginal to wide tumor resection. In the current report, the case of an athlete with desmoplastic fibroma of the distal femur who was treated with extended curettage, heat ablation and artificial bone grafting is described. The postoperative course was uneventful and no recurrence has been observed during the 12-year follow-up period. The patient is able to sit on his heels with a straight back, without pain and is able run a complete marathon.