Antinuclear antibody (ANA) status predicts immune-related adverse events in liver cancer patients undergoing anti-PD-1 therapy.

Immune-related adverse events (irAEs) clinically resemble autoimmune diseases, indicating autoantibodies could be potential biomarkers for the prediction of irAEs. This study aimed to assess the predictive value of peripheral blood antinuclear antibody (ANA) status for irAEs, considering the time and severity of irAEs, as well as treatment outcome in liver cancer patients administered anti-PD-1 therapy. Ninety-three patients with advanced primary liver cancer administered anti-PD-1 treatment were analyzed retrospectively. They were divided into the ANA positive (ANA+, titer ≥ 1:100) and negative (ANA-, titer < 1:100) groups. Development of irAEs, progression-free survival (PFS), and overall survival (OS) were assessed. Compared with ANA- patients, ANA+ cases were more prone to develop irAEs (43.3% vs. 19.2%, P = 0.031). With the increase of ANA titers, the frequency of irAEs increased. The time interval between anti-PD-1 therapy and the onset of irAEs was significantly shorter in ANA+ patients compared with the ANA- group (median, 1.7 months vs. 5.0 months, P = 0.022). Moreover, the time between anti-PD-1 therapy and irAE occurrence decreased with increasing ANA titer. In addition, PFS and OS were decreased in ANA+ patients compared with the ANA- group (median PFS, 2.8 months vs. 4.2 months, P = 0.043; median OS, 21.1 months vs. not reached, P = 0.041). IrAEs occur at higher frequency in ANA+ liver cancer patients undergoing anti-PD-1 therapy. ANA titer could help predict irAE development and treatment outcome in these patients.

An SCD1-dependent mechanoresponsive pathway promotes HCC invasion and metastasis through lipid metabolic reprogramming.

Matrix stiffness promotes hepatocellular carcinoma (HCC) metastasis. This study examined the contribution of lipid metabolic reprogramming to matrix stiffness-induced HCC metastasis. HCC cells were cultured on mechanically tunable polyacrylamide gels and subjected to lipidomic analysis. The key enzyme that responded to matrix stiffness and regulated lipid metabolism was identified. The comparative lipidomic screening revealed that stearoyl-CoA desaturase 1 (SCD1) is a mechanoresponsive enzyme that reprogrammed HCC cell lipid metabolism. The genetic and pharmacological inhibition of SCD1 expression/activity altered the cellular lipid composition, which in turn impaired plasma membrane fluidity and inhibited in vitro invasive motility of HCC cells in response to high matrix stiffness. Knockdown of SCD1 suppressed HCC invasion and metastasis in vivo. Conversely, the overexpression of SCD1 or exogenous administration of its product oleic acid augmented plasma membrane fluidity and rescued in vitro invasive migration in HCC cells cultured on soft substrates, mimicking the effects imposed by high matrix stiffness. In human HCC tissues, collagen content, a marker of increasing matrix stiffness, and increased expression of SCD1 together predicted poor survival of HCC patients. An SCD1-dependent mechanoresponsive pathway that responds to increasing matrix stiffness in the tumor microenvironment promotes HCC invasion and metastasis through lipid metabolic reprogramming.

Suppressing DRP1-mediated mitochondrial fission and mitophagy increases mitochondrial apoptosis of hepatocellular carcinoma cells in the setting of hypoxia.

Transarterial embolization/transarterial chemoembolization (TAE/TACE) is the acceptable palliative treatment for hepatocellular carcinoma (HCC), mainly through ischemic necrosis induced by arterial embolization. However, how HCC cells survive under such ischemic hypoxic condition remains unclear, which can be exploited to potentiate TAE/TACE treatment. We hypothesized that targeting mitophagy can increase HCC cell apoptosis during hypoxia. HCC cells were subjected to hypoxia and then mitophagy was quantified. The role of dynamin-related protein 1 (DRP1) in hypoxia-induced HCC mitophagy was determined. Moreover, the synergistic effect of hypoxia and DRP1 inhibitor on HCC apoptosis was assessed in vitro and in vivo. Clinical association between DRP1 expression and outcome for HCC patients was validated. HCC cells that survived hypoxia showed significantly increased DRP1-mediated mitochondrial fission and mitophagy compared with cells in normoxia. Hypoxia induced mitophagy in surviving HCC cells by enhancing DRP1 expression and its translocation into the mitochondria and excessive mitochondrial fission into fragments. Blocking the DRP1 heightened the possibility of hypoxic cytotoxicity to HCC cells due to impaired mitophagy and increased the mitochondrial apoptosis, which involved decreased in mitochondrial membrane potential and mitochondrial release of apoptosis-inducing factor and cytochrome c. Additionally, DRP1 inhibitor Mdivi-1 suppressed the in vivo growth of hypoxia-exposed HCC cells. High expression of DRP1 was significantly associated with shorter survival in HCC patients. In conclusion, our results demonstrate that blocking DRP1-mediated mitochondrial fission and mitophagy increases the incidence of mitochondrial apoptosis of HCC cells during hypoxia, suggesting the new approach of targeting mitophagy to potentiate TAE/TACE.

Norepinephrine-stimulated HSCs secrete sFRP1 to promote HCC progression following chronic stress via augmentation of a Wnt16B/ß-catenin positive feedback loop.

BACKGROUND: Sustained adrenergic signaling secondary to chronic stress promotes cancer progression; however, the underlying mechanisms for this phenomenon remain unclear. Hepatocellular carcinoma (HCC) frequently develops within fibrotic livers rich in activated hepatic stellate cells (HSCs). Here, we examined whether the stress hormone norepinephrine (NE) could accelerate HCC progression by modulating HSCs activities. METHODS: HCC cells were exposed to conditioned medium (CM) from NE-stimulated HSCs. The changes in cell migration and invasion, epithelial-mesenchymal transition, parameters of cell proliferation, and levels of cancer stem cell markers were analyzed. Moreover, the in vivo tumor progression of HCC cells inoculated with HSCs was studied in nude mice subjected to chronic restraint stress. RESULTS: CM from NE-treated HSCs significantly promoted cell migration and invasion, epithelial-mesenchymal transition (EMT), and expression of cell proliferation-related genes and cancer stem cell markers in HCC cells. These pro-tumoral effects were markedly reduced by depleting secreted frizzled related protein 1 (sFRP1) in CM. The pro-tumoral functions of sFRP1 were dependent on ß-catenin activation, and sFRP1 augmented the binding of Wnt16B to its receptor FZD7, resulting in enhanced ß-catenin activity. Additionally, sFRP1 enhanced Wnt16B expression, reinforcing an autocrine feedback loop of Wnt16B/ß-catenin signaling. The expression of sFRP1 in HSCs promoted HCC progression in an in vivo model under chronic restraint stress, which was largely attenuated by sFRP1 knockdown. CONCLUSIONS: We identify a new mechanism by which chronic stress promotes HCC progression. In this model, NE activates HSCs to secrete sFRP1, which cooperates with a Wnt16B/ß-catenin positive feedback loop. Our findings have therapeutic implications for the treatment of chronic stress-promoted HCC progression.

Suppression of DRP1­mediated mitophagy increases the apoptosis of hepatocellular carcinoma cells in the setting of chemotherapy.

The efficacy of chemotherapy for hepatocellular carcinoma (HCC) remains unsatisfactory, primarily due to inherent self­defense mechanisms (e.g., mitophagy and autophagy). In the present study, we aimed to explore the pro­apoptotic effects of targeting mitophagy to potentiate the efficacy of chemotherapy for HCC. HCC cells were subjected to cisplatin, after which cisplatin­induced mitophagy was quantified by immunofluorescence. Mdivi­1, a specific dynamin­related protein 1 (DRP1) inhibitor, was used to study the role of DRP1 in cisplatin­induced HCC mitophagy. The synergistic effect of cisplatin and the DRP1 inhibitor on HCC was assessed in vitro and in vivo. Accordingly, cisplatin induced mitophagy in surviving HCC cells by activating DRP1. The DRP1 inhibitor (Mdivi­1) increased the apoptosis of cisplatin­treated HCC cells by targeting mitophagy. Mechanistically, Mdivi­1 upregulated Bax and downregulated Bcl­xL, leading to an increase in mitochondrial membrane permeability and subsequent release of cytochrome c from mitochondria into the cytosol, thereby aggravating cisplatin­induced apoptosis in HCC cells. Moreover, Mdivi­1 acted synergistically with cisplatin to suppress HCC xenograft growth in vivo. Our results indicate that targeting cisplatin­mediated mitophagy increases HCC apoptosis via DRP1 inhibition, providing preclinical proof of concept for combination therapy targeting mitophagy to potentiate the efficacy of chemotherapy.

Intermittent hypoxia alleviates increased VEGF and pro-angiogenic potential in liver cancer cells.

Vascular endothelial growth factor (VEGF) is an important angiogenic factor. The VEGF rebound induced by hypoxia following transarterial embolization/chemoembolization for primary liver cancer is associated with treatment failure and poor survival rates in patients. The present study investigated the ability of intermittent hypoxia to alleviate the acute hypoxia-induced increase of VEGF and decrease the pro-angiogenic potential of liver cancer cells. The liver cancer cells were exposed to normoxia, or acute or intermittent hypoxia, and the expression of VEGF was determined using reverse transcription-quantitative polymerase chain reaction analysis and western blotting. The pro-angiogenic effects of acute or intermittent hypoxia-exposed liver cancer cells on endothelial cells were assessed in vitro and in vivo. The expression of VEGF in the liver cancer cells exposed to intermittent hypoxia was significantly lower than that in cells exposed to acute hypoxia. Compared with conditioned medium (CM) from acute hypoxia-exposed liver cancer cells, the CM from intermittent hypoxia-exposed liver cancer cells showed markedly less promotion of proliferation and tube formation in endothelial cells. Activation of the reactive oxygen species (ROS)/NF-κB/hypoxia-inducible factor-1α/VEGF signaling pathway was increased in the liver cancer cells exposed to acute hypoxia. Exposure to ROS scavenger N-acetyl-cysteine or NF-κB inhibitor PDTC inhibited the activation of the above pathway and the expression of VEGF induced by acute hypoxia. The in vivo pro-angiogenic effects of intermittent hypoxia-exposed liver cancer cells on endothelial cells were significantly reduced compared with those of acute hypoxia-exposed liver cancer cells. Intermittent hypoxia may alleviate the acute hypoxia-induced increase of VEGF and decrease the pro-angiogenic potential of liver cancer cells, suggesting a novel treatment strategy.

Activated hepatic stellate cells promote progression of post-heat residual hepatocellular carcinoma from autophagic survival to proliferation.

BACKGROUND: Microscopic residual tumor often occurs after thermal ablation for medium-large hepatocellular carcinoma (HCC), leading to early aggressive recurrence or late relapse during follow-up. The mechanism how microscopic residual HCC cells survive sublethal heat stress and develop rapid outgrowth remains poorly understood. METHODS: HCC cells were exposed to sublethal heat treatment and co-cultured with conditioned media from activated HSCs (HSC-CM). Changes of cell proliferation, parameters of cell autophagy and activation of signaling pathways in heat-treated residual HCC cells were analyzed. An HCC orthotopic model was subjected to partial thermal ablation and antitumor effects of a combined treatment regimen were studied. RESULTS: HCC cells survived sublethal heat stress via activation of autophagy. HSC-CM enhanced autophagic survival within 24 h and then promoted proliferation of heat-treated residual HCC cells through HGF/c-Met signaling. Inhibition of autophagy or c-Met increased apoptosis of heat-treated residual HCC cells and reversed the protective effect of HSC-CM. HGF modulated biological status in autophagic survival or proliferation of heat-treated residual HCC through HGF/c-Met/ERK signaling and downstream components of ATG5/Beclin1 or cyclinD1. In an animal model, inhibiting autophagy in combination with c-Met inhibitor significantly thwarted tumor progression of residual HCC after incomplete thermal ablation via the suppressed autophagy, the decreased proliferation and the increased apoptosis. CONCLUSIONS: Activated HSCs promote progression of residual HCC cells after sublethal heat treatment from autophagic survival to proliferation via HGF/c-Met signaling. A combined treatment regimen of inhibiting autophagy and c-Met signaling could be used to suppress tumor progression of residual HCC after incomplete thermal ablation.

Extracellular matrix collagen I promotes the tumor progression of residual hepatocellular carcinoma after heat treatment.

BACKGROUND: Accelerated malignant behaviors induced by insufficient thermal ablation have been increasingly reported, however, the exact mechanisms are still unclear. Here, we investigated the importance of the extracellular matrix (ECM) in modulating the progression of residual hepatocellular carcinoma (HCC) after heat treatment. METHODS: Heat-exposed residual HCC cells were cultured in different ECM gels. We used basement membrane gel (Matrigel) to simulate the normal microenvironment and collagen I to model the pathological stromal ECM. The alterations of morphology and parameters of proliferation, epithelial-mesenchymal transition (EMT) and stemness were analyzed in vitro and in vivo. RESULTS: Increased collagen I deposition was observed at the periablational zone after incomplete RFA of HCC in a xenograft model. The markers of cell proliferation, EMT, motility and progenitor-like traits of heat-exposed residual HCC cells were significantly induced by collagen I as compared to Matrigel (p values all < 0.05). Importantly, collagen I induced the activation of ERK phosphorylation in heat-exposed residual HCC cells. ERK1/2 inhibitor reversed the collagen I-promoted ERK phosphorylation, cell proliferative, protrusive and spindle-like appearance of heat-treated residual HCC cells in vitro. Moreover, collagen I promoted the in vivo tumor progression of heat-exposed residual HCC cells, and sorafenib markedly reversed the collagen I-mediated protumor effects. CONCLUSIONS: Our findings demonstrate that collagen I could enhance the aggressive progression of residual HCC cells after suboptimal heat treatment and sorafenib may be a treatment approach to thwart this process.