Protocol to screen for Sorafenib resistance regulators using pooled lentiviral shRNA library and a Sorafenib-resistant hepatocellular carcinoma cell model.

Approaches to study therapy resistance in HCC (hepatocellular carcinoma) are limited, especially when using HCC models in vitro. Here, we present a protocol to establish an in vitro Sorafenib-resistant human HCC cell model and conduct an shRNA-mediated synthetic lethal screen in established Sorafenib-resistant HCC cell lines to identify critical regulators of Sorafenib resistance. We describe steps for RNA sequencing and functional analysis to reveal the mode of action of potential candidates in conferring therapy resistance to HCC cells. For complete details on the use and execution of this protocol, please refer to Gao et al. (2021a)1 and Gao et al. (2021b).2.

Anatomic resection versus radiofrequency ablation with an ablative margin ≥ 1.0 cm for solitary small hepatocellular carcinoma measuring ≤ 3 cm: Comparison of long-term outcomes using propensity score matching analysis.

PURPOSE: To compare the long-term outcomes of anatomic resection (AR) and radiofrequency ablation (RFA) with an ablative margin (AM) of ≥ 1.0 cm as first-line treatment for solitary hepatocellular carcinoma measuring ≤ 3 cm. METHODS: Two hundred and fifty-one patients who underwent AR (n = 156) or RFA (ablative margin ≥ 1.0 cm, n = 95) at any of 6 tertiary hospitals from 2009 to 2018 were enrolled. Propensity score matched analysis (PSM) were used to compare overall survival (OS), recurrence-free survival (RFS), and perioperative outcomes. Univariate and multivariate analyses were performed to identify prognostic factors associated with RFS and OS. RESULTS: PSM created 67 patient-pairs. After 96 months of follow-up, RFA with an ablative margin ≥ 1.0 cm and AR showed comparable 1-year, 3-year, 5-year, and 8-year OS rates before (P = 0.580) and after (P = 0.640) PSM. However, RFS was better at 1, 3, 5, and 8 years after AR before (P = 0.0036) and after (P = 0.017) PSM. The operation time and postoperative hospital stay were significantly longer in the AR group than in the RFA group before and after PSM (P < 0.05). Multivariate analysis identified age and type of treatment to be independent prognostic factors for RFS and age and hepatitis C to be associated with OS. CONCLUSIONS: Long-term OS was not significantly different between AR and RFA with an AM ≥ 1.0 cm in patients with a solitary hepatocellular carcinoma measuring ≤ 3 cm; but, RFS appeared to be better after AR than after RFA. However, RFA was associated with fewer perioperative complications and a shorter postoperative hospital stay.

Safety and efficacy of microwave versus radiofrequency ablation for large hepatic hemangioma: a multicenter retrospective study with propensity score matching.

OBJECTIVES: To compare the safety and efficacy of microwave ablation (MWA) and radiofrequency ablation (RFA) for such hemangiomas (5-9.9 cm in diameter). METHODS: This multicenter retrospective cohort study investigated the differences in technical success, ablation time, complete ablation, complications, hospital stay, and clinical response between MWA and RFA. A total of 452 patients with hepatic hemangiomas were screened. Propensity score matching was performed. Univariable and multivariate regression analyses were used. RESULTS: Among the 452 patients, 394 met the eligibility criteria and completed the follow-up. After the propensity score matching analysis, 72 pairs of patients were created. No technical failures were found. The RFA group had a longer ablation time (48.63 ± 18.11 min versus [vs.] 37.18 ± 15.86 min, p < 0.001), higher morbidity of hemoglobinuria (77.78% vs. 50.00%, p < 0.001), and longer hospital stay (5.01 ± 1.56 days vs. 4.34 ± 1.42 days, p < 0.05) than the MWA group. The treatment methods (p = 0.032, OR = 0.105, 95% CI = 0.013-0.821), size of the hemangioma (p = 0.021, OR = 5.243, 95% CI = 1.285-21.391), and time of ablation (p = 0.031, OR = 1.145, 95% CI = 1.013-1.294) were significant independent risk factors associated with hemoglobinuria. No recurrence or delayed complications were observed. There were no differences in complete ablation, clinical response, and health-related quality of life between the groups. CONCLUSIONS: MWA and RFA appear to be effective treatments for large hepatic hemangiomas. However, MWA had a shorter ablation time than RFA, and MWA was associated with fewer hemolysis-related complications and shorter hospital stays. KEY POINTS: • MWA and RFA appear to be effective treatments for large hepatic hemangiomas. • MWA had a shorter ablation time than RFA. • MWA was associated with fewer hemolysis-related complications and shorter hospital stays.

Safety and effectiveness of laparoscopic intratumoral resection facilitated by coagulation of giant hepatic hemangioma: a matched case-control study and literature review.

BACKGROUND: To report the safety and effectiveness of laparoscopic intratumoral resection facilitated by coagulation (LIRC) compared with laparoscopic hepatectomy (LH) in treating giant hepatic hemangioma. METHODS: From 2017 to 2020, 19 consecutive patients with giant hepatic hemangioma (≥ 10 cm) received LIRC in one center. We selected a subgroup of 103 patients treated by LH in other four centers who well matched the 19 consecutive patients treated with LIRC, in a 1:1 fashion based on the tumor location, tumor size, and body mass index. Furthermore, the differences in technical success, operative time, operative blood loss, change of laboratory indexes, hospital stays, complication and clinical responds are compared between the two groups. RESULTS: Technical success was achieved in all 38 patients. Patients in the LIRC group had a relative shorter operative time (P < 0.001) and less operative blood loss (P = 0.003). The serum levels of C-reactive protein (CRP), total bilirubin (TBil), alanine aminotransferase (ALT), and aspartate transaminase (AST) were elevated significantly (P < 0.05) 1 day after the resection and returned to normal within 7 days in both groups; however, relatively lower serum levels of those indexes were observed in the LIRC group (P < 0.05). The total complication rate was relatively lower in the LIRC group compared with the LH group (P = 0.029). Patients in the LIRC group had shorter hospital stays than those in the LH group (P = 0.010). The clinical response was similar in the two groups. CONCLUSIONS: LIRC is safe and effective for treating giant hepatic hemangioma.

YAP/TAZ and ATF4 drive resistance to Sorafenib in hepatocellular carcinoma by preventing ferroptosis.

Understanding the mechanisms underlying evasive resistance in cancer is an unmet medical need to improve the efficacy of current therapies. In this study, a combination of shRNA-mediated synthetic lethality screening and transcriptomic analysis revealed the transcription factors YAP/TAZ as key drivers of Sorafenib resistance in hepatocellular carcinoma (HCC) by repressing Sorafenib-induced ferroptosis. Mechanistically, in a TEAD-dependent manner, YAP/TAZ induce the expression of SLC7A11, a key transporter maintaining intracellular glutathione homeostasis, thus enabling HCC cells to overcome Sorafenib-induced ferroptosis. At the same time, YAP/TAZ sustain the protein stability, nuclear localization, and transcriptional activity of ATF4 which in turn cooperates to induce SLC7A11 expression. Our study uncovers a critical role of YAP/TAZ in the repression of ferroptosis and thus in the establishment of Sorafenib resistance in HCC, highlighting YAP/TAZ-based rewiring strategies as potential approaches to overcome HCC therapy resistance.

Complications of Radiofrequency Ablation for Hepatic Hemangioma: A Multicenter Retrospective Analysis on 291 Cases.

PURPOSE: To report the complications of radiofrequency ablation (RFA) for hepatic hemangioma. PATIENTS AND METHODS: Investigators from six centers performed RFA for hepatic hemangioma and used a standardized follow-up protocol. Data were collected from 291 patients, including 253 patients with hepatic hemangioma 5 to 9.9 cm in diameter (group A) and 38 with hepatic hemangioma ≥ 10 cm (group B). Technical success, complete ablation, and complications attributed to the RFA procedure were reported. Analysis of variance was used to determine whether the major complication rate was related to tumor size or clinical experience. RESULTS: A total of 304 lesions were treated in 291 patients. Technical success was achieved without adverse events in all cases. A total of 301 lesions were completely ablated, including 265 of 265 (100%) lesions in group A, and 36 of 39 (92.31%) in group B. The rate of technology-related complications was similar in groups A and B (5.14% (13/253) and 13.16% (5/38), respectively; P = 0.121). Moreover, all technology-related complications occurred during the early learning curve period. The rate of hemolysis-related complications in two groups were 83.40% (211/253) and 100% (38/38) (P =0.007) and the systemic inflammatory response syndrome-related complications in two groups were 33.99% (86/253) and 86.84% (33/38) (P<0.001). There were no delayed complications in either group. CONCLUSION: RFA is minimally invasive, safe, and effective for hepatic hemangiomas 5 to 9.9 cm in diameter. More clinical data are needed to confirm the safety of RFA for hepatic hemangiomas ≥ 10 cm.

USP29-mediated HIF1α stabilization is associated with Sorafenib resistance of hepatocellular carcinoma cells by upregulating glycolysis.

Understanding the mechanisms underlying evasive resistance in cancer is an unmet medical need to improve the efficacy of current therapies. In hepatocellular carcinoma (HCC), aberrant expression of hypoxia-inducible factor 1 α (HIF1α) and increased aerobic glycolysis metabolism are drivers of resistance to therapy with the multi-kinase inhibitor Sorafenib. However, it has remained unknown how HIF1α is activated and how its activity and the subsequent induction of aerobic glycolysis promote Sorafenib resistance in HCC. Here, we report the ubiquitin-specific peptidase USP29 as a new regulator of HIF1α and of aerobic glycolysis during the development of Sorafenib resistance in HCC. In particular, we identified USP29 as a critical deubiquitylase (DUB) of HIF1α, which directly deubiquitylates and stabilizes HIF1α and, thus, promotes its transcriptional activity. Among the transcriptional targets of HIF1α is the gene encoding hexokinase 2 (HK2), a key enzyme of the glycolytic pathway. The absence of USP29, and thus of HIF1α transcriptional activity, reduces the levels of aerobic glycolysis and restores sensitivity to Sorafenib in Sorafenib-resistant HCC cells in vitro and in xenograft transplantation mouse models in vivo. Notably, the absence of USP29 and high HK2 expression levels correlate with the response of HCC patients to Sorafenib therapy. Together, the data demonstrate that, as a DUB of HIF1α, USP29 promotes Sorafenib resistance in HCC cells, in parts by upregulating glycolysis, thereby opening new avenues for therapeutically targeting Sorafenib-resistant HCC in patients.

Effect of micro-H2O and micro-O2 on the decomposition characteristics of insulating medium C3F7CN gas using molecular dynamics and transition state method.

In recent years, heptafluoroisobutyronitrile (C3F7CN) has been proved to be a potential eco-friendly insulating medium to replace sulfur hexafluoride (SF6, the strong greenhouse gas). In this paper, the effect of micro-H2O and micro-O2 on the decomposition of C3F7CN was investigated based on the reactive force field molecular dynamics (ReaxFF-MD) and transition state theory (TST). It was found that H2O obviously promoted the decomposition of C3F7CN, and new products HF, COF2, CO, and NO were generated. The influence of O2 on the C3F7CN dissociation was weaker than that of H2O, and O2 slightly promoted the C3F7CN decomposition only when 50 O2 molecules were added. The simultaneous presence of H2O and O2 promoted the decomposition of C3F7CN, the promotion of which was closed to H2O existing alone. The calculation results showed that the energy barriers of the two reactions forming COF2 were 31.38 kcal/mol and 23.85 kcal/mol, respectively, which indicated that the reactions were difficult to proceed spontaneously. The energy barrier of F + H2O → HF + OH was relatively lower than that of COF2. These values corresponded well to the ReaxFF simulation results. This study provides theoretical support for the effect of H2O and O2 on the decomposition of C3F7CN.

LATS1 but not LATS2 represses autophagy by a kinase-independent scaffold function.

Autophagy perturbation represents an emerging therapeutic strategy in cancer. Although LATS1 and LATS2 kinases, core components of the mammalian Hippo pathway, have been shown to exert tumor suppressive activities, here we report a pro-survival role of LATS1 but not LATS2 in hepatocellular carcinoma (HCC) cells. Specifically, LATS1 restricts lethal autophagy in HCC cells induced by sorafenib, the standard of care for advanced HCC patients. Notably, autophagy regulation by LATS1 is independent of its kinase activity. Instead, LATS1 stabilizes the autophagy core-machinery component Beclin-1 by promoting K27-linked ubiquitination at lysine residues K32 and K263 on Beclin-1. Consequently, ubiquitination of Beclin-1 negatively regulates autophagy by promoting inactive dimer formation of Beclin-1. Our study highlights a functional diversity between LATS1 and LATS2, and uncovers a scaffolding role of LATS1 in mediating a cross-talk between the Hippo signaling pathway and autophagy.

The SIAH2-NRF1 axis spatially regulates tumor microenvironment remodeling for tumor progression.

The interactions between tumor cells with their microenvironments, including hypoxia, acidosis and immune cells, lead to the tumor heterogeneity which promotes tumor progression. Here, we show that SIAH2-NRF1 axis remodels tumor microenvironment through regulating tumor mitochondrial function, tumor-associated macrophages (TAMs) polarization and cell death for tumor maintenance and progression. Mechanistically, low mitochondrial gene expression in breast cancers is associated with a poor clinical outcome. The hypoxia-activated E3 ligase SIAH2 spatially downregulates nuclear-encoded mitochondrial gene expression including pyruvate dehydrogenase beta via degrading NRF1 (Nuclear Respiratory Factor 1) through ubiquitination on lysine 230, resulting in enhanced Warburg effect, metabolic reprogramming and pro-tumor immune response. Dampening NRF1 degradation under hypoxia not only impairs the polarization of TAMs, but also promotes tumor cells to become more susceptible to apoptosis in a FADD-dependent fashion, resulting in secondary necrosis due to the impairment of efferocytosis. These data represent that inhibition of NRF1 degradation is a potential therapeutic strategy against cancer.

Zyxin-Siah2-Lats2 axis mediates cooperation between Hippo and TGF-ß signalling pathways.

The evolutionarily conserved Hippo pathway is a regulator that controls organ size, cell growth and tissue homeostasis. Upstream signals of the Hippo pathway have been widely studied, but how microenvironmental factors coordinately regulate this pathway remains unclear. In this study, we identify LIM domain protein Zyxin, as a scaffold protein, that in response to hypoxia and TGF-ß stimuli, forms a ternary complex with Lats2 and Siah2 and stabilizes their interaction. This interaction facilitates Lats2 ubiquitination and degradation, Yap dephosphorylation and subsequently activation. We show that Zyxin is required for TGF-ß and hypoxia-induced Lats2 downregulation and deactivation of Hippo signalling in MDA-MB-231 cells. Depletion of Zyxin impairs the capability of cell migration, proliferation and tumourigenesis in a xenograft model. Zyxin is upregulated in human breast cancer and positively correlates with histological stages and metastasis. Our study demonstrates that Zyxin-Lats2-Siah2 axis may serve as a potential therapeutic target in cancer treatment.

Hypoxia regulates Hippo signalling through the SIAH2 ubiquitin E3 ligase.

The Hippo signalling pathway plays important roles in animal development, physiology and tumorigenesis. Understanding how the activity of this pathway is regulated by the cellular microenvironment remains a major challenge. Here we elucidate a molecular mechanism by which hypoxia deactivates Hippo signalling. We demonstrate that the E3 ubiquitin ligase SIAH2 stimulates YAP by destabilizing LATS2, a critical component of the Hippo pathway, in response to hypoxia. Loss of SIAH2 suppresses tumorigenesis in a LATS2-dependent manner in a xenograft mouse model. We further show that YAP complexes with HIF1α and is essential for HIF1α stability and function in tumours in vivo. LATS2 is downregulated in human breast tumours and negatively correlates with SIAH2 expression levels, indicating that the SIAH2-LATS2 pathway may have a role in human cancer. Our data uncover oxygen availability as a microenvironment signal for the Hippo pathway and have implications for understanding the regulation of Hippo signalling in tumorigenesis.