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Circulating mitochondrial DNA promotes M2 polarization of tumor associated macrophages and HCC resistance to sorafenib
Mitochondrial damage-associated molecular patterns (DAMPs) including mitochondrial DNA (mtDNA), TFAM (transcription factor A, mitochondrial), and ATP, which play crucial roles in the regulation of inflammatory environment in human diseases. However, the role of mitochondrial DAMPs in regulating tumor microenvironment (TME) remains unclear. Herein, we demonstrate that infiltration of M2-type tumor-associated macrophages (TAMs) was correlated with the resistance of hepatocellular carcinoma (HCC) to sorafenib. We found that cell-free mtDNA in the plasma was significantly increased in sorafenib-resistant HCC mice. Sorafenib induced mitochondrial dysfunction and promoted the release of mtDNA into extracellular matrix of HCC. Macrophages retook the mtDNA in the TME of HCC, activated TLR9 signaling, and promoted the activation of NF-κB and the polarization of TAMs into M2. Application of DNase I to digest mtDNA or depletion of macrophages with clodronate liposomes reduced M2 macrophage infiltration, decreased the growth of HCC, and sensitized the tumors to sorafenib. Furthermore, we showed that blocking the activation of TLR9 enhanced the therapeutic effect of sorafenib in HCC. Together, we demonstrate that sorafenib treatment leads to the release of mtDNA into TME in HCC, which in turn facilitates the polarization of TAMs into M2 macrophages through TLR9 activation and aggravates the resistance of HCC to sorafenib. Our study reveals a novel mechanism underlying circulating mtDAMPs in remodeling the HCC microenvironment by reprograming the TAMs and provides a new strategy for improving the therapeutic effect of sorafenib and overcoming its resistance in HCC.
Stromal architecture and fibroblast subpopulations with opposing effects on outcomes in hepatocellular carcinoma
Dissecting the spatial heterogeneity of cancer-associated fibroblasts (CAFs) is vital for understanding tumor biology and therapeutic design. By combining pathological image analysis with spatial proteomics, we revealed two stromal archetypes in hepatocellular carcinoma (HCC) with different biological functions and extracellular matrix compositions. Using paired single-cell RNA and epigenomic sequencing with Stereo-seq, we revealed two fibroblast subsets CAF-FAP and CAF-C7, whose spatial enrichment strongly correlated with the two stromal archetypes and opposing patient prognosis. We discovered two functional units, one is the intratumor inflammatory hub featured by CAF-FAP plus CD8_PDCD1 proximity and the other is the marginal wound-healing hub with CAF-C7 plus Macrophage_SPP1 co-localization. Inhibiting CAF-FAP combined with anti-PD-1 in orthotopic HCC models led to improved tumor regression than either monotherapy. Collectively, our findings suggest stroma-targeted strategies for HCC based on defined stromal archetypes, raising the concept that CAFs change their transcriptional program and intercellular crosstalk according to the spatial context.
Thyroid hormones inhibit tumor progression and enhance the antitumor activity of lenvatinib in hepatocellular carcinoma via reprogramming glucose metabolism
Thyroid hormones (THs) dysfunctions have been demonstrated to be associated with the risk of developing different types of cancers. The role of THs in regulating hepatocellular carcinoma (HCC) progression is still controversial. We demonstrated that T3 can inhibit HCC progression by enhancing the expression of THRSP. Mechanistically, T3 can activate tumor suppressor LKB1/AMPK/Raptor signaling as well as oncogenic PI3K/Akt signaling in HCC. Interestingly, T3-induced THRSP can augment the activation of LKB1/AMPK/Raptor signaling, yet inhibit T3-induced PI3K/Akt signaling activation, thereby preventing mTOR-induced nuclear translocation of HIF-1α, and ultimately suppressing ENO2-induced glycolysis and HCC progression. More importantly, the exogenous T3 enhances the antitumor effect of multikinase inhibitor lenvatinib in vitro and in vivo by regulating glycolysis. Our findings reveal the role and mechanism of THs in HCC progression and glucose metabolism and provide new potential therapeutic strategies for HCC treatment and drug resistance reversal.
SENP3 inhibition suppresses hepatocellular carcinoma progression and improves the efficacy of anti-PD-1 immunotherapy
The importance of SUMOylation in tumorigenesis has received increasing attention, and research on therapeutic agents targeting this pathway has progressed. However, the potential function of SUMOylation during hepatocellular carcinoma (HCC) progression and the underlying molecular mechanisms remain unclear. Here, we identified that SUMO-Specific Peptidase 3 (SENP3) was upregulated in HCC tissues and correlated with a poor prognosis. Multiple functional experiments demonstrated that SENP3 promotes the malignant phenotype of HCC cells. Mechanistically, SENP3 deSUMOylates RACK1 and subsequently increases its stability and interaction with PKCβII, thereby promoting eIF4E phosphorylation and translation of oncogenes, including Bcl2, Snail and Cyclin D1. Additionally, tumor-intrinsic SENP3 promotes the infiltration of tumor-associated macrophages (TAMs) while reducing cytotoxic T cells to facilitate immune evasion. Mechanistically, SENP3 promotes translation of CCL20 via the RACK1 /eIF4E axis. Liver-specific knockdown of SENP3 significantly inhibits liver tumorigenesis in a chemically induced HCC model. SENP3 inhibition enhances the therapeutic efficacy of PD-1 blockade in an HCC mouse model. Collectively, SENP3 plays cell-intrinsic and cell-extrinsic roles in HCC progression and immune evasion by modulating oncogene and cytokine translation. Targeting SENP3 is a novel therapeutic target for boosting HCC responsiveness to immunotherapy.
BAIAP2L2 promotes the malignancy of hepatocellular carcinoma via GABPB1-mediated reactive oxygen species imbalance
Hepatocellular carcinoma (HCC) is a common type of cancer worldwide and ranks as the fourth leading cause of cancer-related deaths. This research investigation identified an upregulation of BAI1-associated protein 2-like 2 (BAIAP2L2) in HCC tissues, which was found to be an independent prognostic factor for overall survival in HCC patients. BAIAP2L2 was observed to enhance cell proliferation, metastasis, stemness, cell cycle progression, and inhibit apoptosis in HCC. Mechanistically, NFκB1 was found to stimulate BAIAP2L2 transcription by directly binding to its promoter region. BAIAP2L2 interacts with GABPB1 to inhibit its ubiquitin-mediated degradation and promote its nuclear translocation. BAIAP2L2 inhibits the levels of reactive oxygen species (ROS) by regulating GABPB1, thereby promoting cancer properties in HCC and reducing the sensitivity of HCC to lenvatinib. In summary, this study elucidates the role and underlying mechanism of BAIAP2L2 in HCC, providing a potential biomarker and therapeutic target for this disease.
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