Deficiency of Carbamoyl Phosphate Synthetase 1 Engenders Radioresistance in Hepatocellular Carcinoma via Deubiquitinating c-Myc

Wogonin potentiates the irradiation effect on hepatocellular carcinoma by activating the Hippo-Yes-associated protein/transcriptional co-activator with PDZ-binding motif pathway

OBJECTIVE

To investigate whether wogonin increases the radiosensitivity of hepatocellular carcinoma (HCC) cells by activating Hippo-Yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) signaling.

METHODS

HCC cells were treated with irradiation and wogonin; their proliferation and apoptosis were evaluated. Xenograft models were established to assess the radio-synergistic effects of wogonin; we evaluated whether wogonin influences the efficacy of radiotherapy in HCC cells by activating Hippo-YAP/TAZ signaling.

RESULTS

Fifty micromolar wogonin enhanced the radiosensitivity of HCC cells; 4-Gy X-rays promoted apoptosis in HCC cells. Wogonin pretreatment significantly increased radiosensitivity. In xenograft models, tumor weight and volume in the 100 mg/kg wogonin plus irradiation group were significantly reduced; pYAP and pTAZ levels were downregulated in HCC cells treated with radiotherapy. Following treatment with 4-Gy X-rays and 100 μM wogonin, the relative pYAP/total YAP and pTAZ/total TAZ ratios increased. We identified the possible target genes of YAP/TAZ: AXL, CCN1, and CCN2. WB results revealed the upregulation of AXL, CCN1, and CCN2 in the irradiation group. However, in the group receiving irradiation and wogonin, the protein expression levels of AXL, CCN1, and CCN2 were downregulated. XMU-MP-1 inhibited pYAP and pTAZ expression in the combination treatment group, thereby promoting AXL, CCN1, and CCN2 expression. The proliferative ability of HCC cells in the wogonin plus irradiation group was partially recovered following treatment with XMU-MP-1. Apoptosis in HCC cells was reversed after pretreatment with 2 μM XMU-MP-1 in the wogonin plus irradiation group.

CONCLUSION

Wogonin may modulate Hippo-YAP/TAZ signaling and enhance the radiosensitivity of HCCs.

Radiosensitization Strategies for Hepatocellular Carcinoma: Mechanisms, Therapeutic Advances, and Clinical Perspectives

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide, with treatment efficacy limited by late-stage diagnosis, frequent recurrence, and therapeutic resistance. Radiotherapy is a key local treatment for HCC; however, its efficacy is frequently limited by intrinsic tumor radioresistance. This review discusses strategies to improve the therapeutic response of HCC to radiotherapy. Targeting DNA repair mechanisms can block tumor cells from recovering after radiation-induced damage, whereas modulating cell cycle arrest and programmed cell death pathways (e.g., apoptosis, autophagy) diminishes their survival capacity. Furthermore, remodeling the tumor microenvironment-through hypoxia alleviation, metabolic reprogramming, oxidative stress regulation, and immune activation-may potentiate radiotherapy efficacy. Technological advances, such as stereotactic body radiotherapy and nanomaterial-based approaches, have also improved the precision and effectiveness of radiotherapy. Clinically, combining radiotherapy with systemic therapies (e.g., immune checkpoint inhibitors and antiangiogenic agents) has demonstrated preliminary promise in enhancing treatment outcomes. However, translating preclinical findings into clinical practice remains challenging due to tumor heterogeneity, normal tissue toxicity, and the lack of predictive biomarkers for treatment selection. Future research should focus on integrating molecular profiling with multimodal therapies to enable personalized radiosensitization and bridge the gap between mechanistic insights and clinical outcomes.

Unlocking the Radiosensitizing Potential of MYC Inhibition in Neuroendocrine Malignancies

The MYC family of transcription factors-comprising c-MYC, N-MYC, and L-MYC-plays a pivotal role in oncogenesis, driving cancer progression and resistance to therapy. While MYC proteins have long been considered challenging drug targets due to their intricate structures, recent advances have led to the development of promising inhibitors. This review explores the role of MYC overexpression in promoting radiation therapy resistance in aggressive neuroendocrine malignancies through multiple mechanisms, including increased tumor cell invasion, enhanced DNA damage repair and oxidative stress management, prosurvival autophagy, survival of circulating tumor cells, angiogenesis, awakening from dormancy, and modulation of chronic inflammation and host immunity. Paradoxically, MYC overexpression can also enhance radiosensitivity in certain cancer cells by driving proapoptotic pathways, such as reactive oxygen species-induced DNA damage that overwhelms cellular repair mechanisms, ultimately leading to cell death. Additionally, we provide a comprehensive summary of direct MYC inhibitors, detailing their current stage of preclinical and clinical development as novel anticancer therapeutics. This review highlights the role of MYC in cancer metastasis and radiation therapy resistance while examining the potential of MYC inhibitors as radiosensitizers in adult and pediatric neuroendocrine malignancies, including small cell lung cancer, large cell neuroendocrine lung cancer, Merkel cell carcinoma, neuroendocrine-differentiated prostate cancer, neuroblastoma, central nervous system embryonal tumors, and medulloblastoma.

Fn14-targeting, NIR-II responsive nanomaterials for enhanced radiotherapy against glioblastomas

Radiotherapy is a common treatment option for patients with glioblastoma multiforme. However, tumor heterogeneity causes varying responses to radiation among different tumor subpopulations. Cancer cells that endure radiotherapy exhibit radioresistance, resulting in the ineffectiveness of radiation therapy and eventual tumor relapse. In this study, we discovered that the fibroblast growth factor-inducible 14 (Fn14)-positive tumor cells were enriched in tumor residual foci after radiation, ultimately leading to treatment failure. Fn14-expressing glioma cells survived ionizing radiation through preferential activation of DNA damage checkpoint response. We have thus engineered an Fn14-targeting and NIR-II responsive plasmonic gold nanosystem named Fn14-AuNPs, which can precisely internalize into Fn14-overexpressed glioma cells and have an excellent BBB-crossing capability. As gold nanoparticles, by inhibition of DNA repair processes and induction of G2/M cells cycle arrest, Fn14-AuNPs nanoparticles improved the radiosensitivity of tumor cells. Meanwhile, Fn14-AuNPs induced localized heat under NIR-II photoirradiation, thus impeding RT-induced DNA damage checkpoint response. This versatile nanosensitizer, combined with NIR-II laser photoirradiation, can eradicate radioresistant subpopulations of glioblastoma and improve the therapeutic effect of radiotherapy. This finding presents an effective radiosensitization strategy by targeting radioresistant subpopulations, which can efficiently overcome the constraints imposed in clinical radiotherapy and offer a hopeful avenue to enhance the treatment effectivity of radiotherapy in glioblastoma.

Increased Sirtuin 6 Activity in Tumor Cells Can Prompt CD4-Positive T-Cell Differentiation Into Regulatory T Cells and Impede Immune Surveillance in the Microenvironment

Background

Sirtuin 6 (Sirt6) is expressed at increased levels in many tumors and may be involved in immunoregulation. The present study investigated how Sirt6 in tumor cells affects immune surveillance.

Methods

The human tumor cell lines A2780, HeLa, Huh7, MBA-MD-231, SMMC-7721 and SW480 were incubated with UBCS039, a target-selective activator of Sirt6, to stimulate Sirt6 activity. These cells, following washing to remove residual UBCS039, were cultured with human naive CD4+ T cells in the Transwell to observe the T cell differentiation. Regulatory T cells (Tregs) among CD4+ T cells and the levels of various cytokines and adenosine (ADO), an immunosuppressive metabolite, in the culture medium, were measured via flow cytometry. The treated tumor cells were examined via transcriptomic analysis. The transcriptomic results, as well as programmed cell death protein-1 (PD-1), programmed cell death-ligand 1 (PD-L1) and Sirt6 expression in tumor cells and CD4+ T cells were verified via real-time polymerase chain reaction (PCR).

Results

Following culture with UBSC039-pretreated tumor cells, the proportion of Tregs among CD4+ T cells was significantly increased. PD-L1 and Sirt6 expressions in UBS039-pretreated tumor cells and PD-1 expression in cocultured CD4+ T cells were also increased. Moreover, the ADO level increased, and the interleukin (IL)-10, interferon (IFN)-α2, IFN-γ and monocyte chemoattractant protein-1 (MCP-1) levels decreased in the coculture medium. Transcriptomic analysis revealed significant downregulation of the antitumor genes BASP1, CPS1, GNG11, MFAP5, NNMT and SMOC1, upregulation of the tumor-promoting genes FOXA2, GSTP1, RASEF and ZNF844, and activation of adherens junctions, tumor necrosis factor (TNF)-signaling and the circadian rhythm pathway in UBCS039-pretreated SMMC-7721 cells. The above results were verified in all six cell lines.

Conclusions

The present study suggested that increased Sirt6 expression and activity in tumor cells can suppress immune surveillance by increasing Treg, ADO, PD-1 and PD-L1 levels, decreasing IFN-γ production, and altering tumor-promoting and antitumor gene expression in the microenvironment.

Exploring prognosis and therapeutic strategies for HBV-HCC patients based on disulfidptosis-related genes

Background

Hepatocellular carcinoma (HCC) accounts for over 80% of primary liver cancers and is the third leading cause of cancer-related deaths worldwide. Hepatitis B virus (HBV) infection is the primary etiological factor. Disulfidptosis is a newly discovered form of regulated cell death. This study aims to develop a novel HBV-HCC prognostic signature related to disulfidptosis and explore potential therapeutic approaches through risk stratification based on disulfidptosis.

Methods

Transcriptomic data from HBV-HCC patients were analyzed to identify BHDRGs. A prognostic model was established and validated using machine learning, with internal datasets and external datasets for verification. We then performed immune cell infiltration analysis, tumor microenvironment (TME) analysis, and immunotherapy-related analysis based on the prognostic signature. Besides, RT-qPCR and immunohistochemistry were conducted.

Results

A prognostic model was constructed using five genes (DLAT, STC2, POF1B, S100A9, and CPS1). A corresponding prognostic nomogram was developed based on riskScores, age, stage. Stratification by median risk score revealed a significant correlation between the prognostic signature and TME, tumor immune cell infiltration, immunotherapy efficacy, and drug sensitivity. The results of the experiments indicate that DLAT expression is higher in tumor tissues compared to adjacent tissues. DLAT expression is higher in HBV-HCC tumor tissues compared to normal tissues.

Conclusion

This study stratifies HBV-HCC patients into distinct subgroups based on BHDRGs, establishing a prognostic model with significant implications for prognosis assessment, TME remodeling, and personalized therapy in HBV-HCC patients.

UBAP2 contributes to radioresistance by enhancing homologous recombination through SLC27A5 ubiquitination in hepatocellular carcinoma

Radiotherapy stands as an effective method in the clinical treatment of hepatocellular carcinoma (HCC) patients. However, both primary and acquired radioresistance limit its clinical application in HCC. Therefore, investigating the mechanism of radioresistance may provide other options for treating HCC. Based on single-cell RNA sequencing (scRNA-seq) and HCC transcriptome datasets, 227 feature genes with prognostic value were selected to establish the tSNE score. The tSNE score emerged as an independent prognostic factor for HCC and correlated with cell proliferation and radioresistance-related biological functions. UBAP2 was identified as the most relevant gene with the tSNE score, consistently elevated in human HCC samples, and positively associated with patient prognosis. Functionally, UBAP2 knockdown impeded HCC development and reduced radiation resistance in vitro and in vivo. The ectopic expression of SLC27A5 reversed the effects of UBAP2. Mechanically, we uncovered that UBAP2, through the ubiquitin-proteasome system, decreased the homologous recombination-related gene RAD51, not the non-homologous end-joining (NHEJ)-related gene CTIP, by degrading the antioncogene SLC27A5, thereby generating radioresistance in HCC. The findings recapitulated that UBAP2 promoted HCC progression and radioresistance via SLC27A5 stability mediated by the ubiquitin-proteasome pathway. It was also suggested that targeting the UBAP2/SLC27A5 axis could be a valuable radiosensitization strategy in HCC.

Loss of Carbamoyl Phosphate Synthetase 1 Potentiates Hepatocellular Carcinoma Metastasis by Reducing Aspartate Level

Hepatocellular carcinoma (HCC) is one of the most lethal cancers worldwide. Numerous studies have shown that metabolic reprogramming is crucial for the development of HCC. Carbamoyl phosphate synthase 1 (CPS1), a rate-limiting enzyme in urea cycle, is an abundant protein in normal hepatocytes, however, lacking systemic research in HCC. It is found that CPS1 is low-expressed in HCC tissues and circulating tumor cells, negatively correlated with HCC stage and prognosis. Further study reveals that CPS1 is a double-edged sword. On the one hand, it inhibits the activity of phosphatidylcholine-specific phospholipase C to block the biosynthesis of diacylglycerol (DAG), leading to the downregulation of the DAG/protein kinase C pathway to inhibit invasion and metastasis of cancer cells. On the other hand, CPS1 promotes cell proliferation by increasing intracellular S-adenosylmethionin to enhance the m6A modification of solute carrier family 1 member 3 mRNA, a key transporter for aspartate intake. Finally, CPS1 overexpressing adeno-associated virus can dampen HCC progression. Collectively, this results uncovered that CPS1 is a switch between HCC proliferation and metastasis by increasing intracellular aspartate level.

Dual role of Nrf2 signaling in hepatocellular carcinoma: promoting development, immune evasion, and therapeutic challenges

Hepatocellular carcinoma (HCC) is the predominant form of liver cancer and ranks as the third leading cause of cancer-related mortality globally. The liver performs a wide range of tasks and is the primary organ responsible for metabolizing harmful substances and foreign compounds. Oxidative stress has a crucial role in growth and improvement of hepatocellular carcinoma (HCC). Nuclear factor erythroid 2 (1)-related factor 2 (Nrf2) is an element that regulates transcription located in the cytoplasm. It controls the balance of redox reactions by stimulating the expression of many genes that depend on antioxidant response elements. Nrf2 has contrasting functions in the normal, healthy liver and HCC. In the normal liver, Nrf2 provides advantageous benefits, while in HCC it promotes harmful effects that support the growth and survival of HCC. Continuous activation of Nrf2 has been detected in HCC and promotes its advancement and aggressiveness. In addition, Activation of Nrf2 may lead to immune evasion, weakening the immune cells' ability to attack tumors and thereby promoting tumor development. Furthermore, chemoresistance in HCC, which is considered a form of stress response to chemotherapy medications, significantly impedes the effectiveness of HCC treatment. Stress management is typically accomplished by activating specific signal pathways and chemical variables. One important element in the creation of chemoresistance in HCC is nuclear factor-E2-related factor 2 (Nrf2). Nrf2 is a transcription factor that regulates the activation and production of a group of genes that encode proteins responsible for protecting cells from damage. This occurs through the Nrf2/ARE pathway, which is a crucial mechanism for combating oxidative stress within cells.

From the Inside Out: Exposing the Roles of Urea Cycle Enzymes in Tumors and Their Micro and Macro Environments

Catabolic pathways change in anabolic diseases such as cancer to maintain metabolic homeostasis. The liver urea cycle (UC) is the main catabolic pathway for disposing excess nitrogen. Outside the liver, the UC enzymes are differentially expressed based on each tissue's needs for UC intermediates. In tumors, there are changes in the expression of UC enzymes selected for promoting tumorigenesis by increasing the availability of essential UC substrates and products. Consequently, there are compensatory changes in the expression of UC enzymes in the cells that compose the tumor microenvironment. Moreover, extrahepatic tumors induce changes in the expression of the liver UC, which contribute to the systemic manifestations of cancer, such as weight loss. Here, we review the multilayer changes in the expression of UC enzymes throughout carcinogenesis. Understanding the changes in UC expression in the tumor and its micro and macro environment can help identify biomarkers for early cancer diagnosis and vulnerabilities that can be targeted for therapy.

Copper in Cancer: from transition metal to potential target

In recent years, with the continuous in-depth exploration of the molecular mechanisms of tumorigenesis, numerous potential new targets for cancer treatment have been identified, some of which have been further developed in clinical practice and have produced positive outcomes. Notably, researchers' initial motivation for studying copper metabolism in cancer stems from the fact that copper is a necessary trace element for organisms and is closely connected to body growth and metabolism. Moreover, over the past few decades, considerable progress has been made in understanding the molecular processes and correlations between copper and cancer. Certain achievements have been made in the development and use of relevant clinical medications. The concept of "cuproptosis," a novel concept that differs from previous forms of cell death, was first proposed by a group of scientists last year, offering fresh perspectives on the targeting capabilities of copper in the treatment of cancer. In this review, we introduced the fundamental physiological functions of copper, the key components of copper metabolism, and a summary of the current research contributions on the connection between copper and cancer. In addition, the development of new copper-based nanomaterials and their associated mechanisms of action are discussed. Finally, we described how the susceptibility of cancer cells to this metallic nutrition could be leveraged to further improve the existing cancer treatment paradigm in the new setting.

The Mechanism of Ubiquitination or Deubiquitination Modifications in Regulating Solid Tumor Radiosensitivity

Radiotherapy, a treatment method employing radiation to eradicate tumor cells and subsequently reduce or eliminate tumor masses, is widely applied in the management of numerous patients with tumors. However, its therapeutic effectiveness is somewhat constrained by various drug-resistant factors. Recent studies have highlighted the ubiquitination/deubiquitination system, a reversible molecular modification pathway, for its dual role in influencing tumor behaviors. It can either promote or inhibit tumor progression, impacting tumor proliferation, migration, invasion, and associated therapeutic resistance. Consequently, delving into the potential mechanisms through which ubiquitination and deubiquitination systems modulate the response to radiotherapy in malignant tumors holds paramount significance in augmenting its efficacy. In this paper, we comprehensively examine the strides made in research and the pertinent mechanisms of ubiquitination and deubiquitination systems in governing radiotherapy resistance in tumors. This underscores the potential for developing diverse radiosensitizers targeting distinct mechanisms, with the aim of enhancing the effectiveness of radiotherapy.

MYC in liver cancer: mechanisms and targeted therapy opportunities

MYC, a major oncogenic transcription factor, regulates target genes involved in various pathways such as cell proliferation, metabolism and immune evasion, playing a critical role in the tumor initiation and development in multiple types of cancer. In liver cancer, MYC and its signaling pathways undergo significant changes, exerting a profound impact on liver cancer progression, including tumor proliferation, metastasis, dedifferentiation, metabolism, immune microenvironment, and resistance to comprehensive therapies. This makes MYC an appealing target, despite it being previously considered an undruggable protein. In this review, we discuss the role and mechanisms of MYC in liver physiology, chronic liver diseases, hepatocarcinogenesis, and liver cancer progression, providing a theoretical basis for targeting MYC as an ideal therapeutic target for liver cancer. We also summarize and prospect the strategies for targeting MYC, including direct and indirect approaches to abolish the oncogenic function of MYC in liver cancer.

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.