Sirolimus-based immunosuppression improves outcomes in liver transplantation recipients with hepatocellular carcinoma beyond the Hangzhou criteria

Immunosuppression in liver transplant oncology: position paper of the Italian Board of Experts in Liver Transplantation (I-BELT)

Liver transplant oncology (TO) represents an area of increasing clinical and scientific interest including a heterogeneous group of clinical-pathological settings. Immunosuppressive management after LT is a key factor relevantly impacting result. However, disease-related guidance is still lacking, and many open questions remain in the field. Based on such a substantial lack of solid evidences, the Italian Board of Experts in Liver Transplantation (I-BELT) (a working group including representatives of all national transplant centers), unprecedently promoted a methodologically sound consensus conference on the topic, based on the GRADE approach. The group final recommendations are herein presented and commented. The 18 PICOs and Statements and their levels of evidence and grades of recommendation are reported and grouped into seven areas: (1) risk stratification by histopathological and bio-molecular parameters and role of mTORi post-LT; (2) steroids and HCC recurrence; (3) management of immunosuppression when HCC recurs after LT; (4) mTORi monotherapy; (5) machine perfusion and HCC recurrence after LT; (6) physiopathology of tumor-infiltrating lymphocytes and immunosuppression, the role of inflammation; (7) immunotherapy in liver transplanted patients. The interest in mammalian targets of rapamycin inhibitors (mTORi), for steroid avoidance and the need for a reduction to CNI exposure emerged from the consensus process. A selected list of unmet needs prompting further investigations have also been developed. The so far heterogeneous and granular approach to immunosuppression in oncologic patients deserves greater efforts for a more standardized therapeutic response to the different clinical scenarios. This consensus process makes a first unprecedented step in this direction, to be developed on a larger scale.

mTOR inhibitor reduces nontumour-related death in liver transplantation for hepatocellular carcinoma

Sirolimus is a regularly applied immunosuppressant for patients undergoing liver transplantation (LT) for hepatocellular carcinoma (HCC). Sirolimus not only significantly inhibits HCC recurrence but also protects renal function. However, the improvement effect of sirolimus on nontumour-related death in patients is still unknown. The aim of our study was to investigate the therapeutic effect of sirolimus on nontumour-related deaths. In this study, we retrospectively enrolled 403 LT patients with HCC from January 1, 2015, to December 31, 2018. The median follow-up time was 47.1 months. The patients were divided into the sirolimus group (N = 184) and the sirolimus-free group (N = 219). There were no significant differences between the sirolimus group and the sirolimus-free group in survival (P = 0.054). In transplant patients who exceeded the Milan or Hangzhou criteria, the sirolimus group achieved higher survival than the sirolimus-free group (P = 0.005; P = 0.02). Moreover, multivariate analysis showed that sirolimus strongly reduced the hazard ratio (HR) for nontumour-related death in LT patients who exceeded the Milan (HR: 0.42; 95% CI: 0.18-1; P = 0.05) or Hangzhou criteria (HR: 0.26; 95% CI: 0.08-0.89; P = 0.032). HCC recurrence increased the risk of nontumour-related death. In conclusion, sirolimus-based immunosuppression can significantly reduce nontumour-related death in LT patients who exceed the criteria for transplantation. In addition, this finding will further promote the application of sirolimus after liver transplantation for hepatocellular carcinoma.

Ginsenoside Rk1 induces autophagy-dependent apoptosis in hepatocellular carcinoma by AMPK/mTOR signaling pathway

Hepatocellular carcinoma (HCC) is the third most lethal cancer in the world. Recent studies have shown that suppression of autophagy plays an important role in the development of HCC. Ginsenoside Rk1 is a protopanaxadiol saponin isolated from ginseng and has a significant anti-tumor effect, but its role and mechanism in HCC are still unclear. In this study, a mouse liver cancer model induced by diethylnitrosamine and carbon tetrachloride (DEN + CCl4) was employed to investigate the inhibitory effect of Rk1 on HCC. The results demonstrate that ginsenoside Rk1 effectively inhibits liver injury, liver fibrosis, and cirrhosis during HCC progression. Transcriptome data analysis of mouse liver tissue reveals that ginsenoside Rk1 significantly regulates the AMPK/mTOR signaling pathway, autophagy pathway, and apoptosis pathway. Subsequent studies show that ginsenoside Rk1 induces AMPK protein activation, upregulates the expression of autophagy marker LC3-II protein to promote autophagy, and then downregulates the expression of Bcl2 protein to trigger a caspase cascade reaction, activating AMPK/mTOR-induced toxic autophagy to promote cells death. Importantly, co-treatment of ginsenoside Rk1 with autophagy inhibitors can inhibit apoptosis of HCC cells, once again demonstrating the ability of ginsenoside Rk1 to promote autophagy-dependent apoptosis. In conclusion, our study demonstrates that ginsenoside Rk1 inhibits the development of primary HCC by activating toxic autophagy to promote apoptosis through the AMPK/mTOR pathway. These findings confirm that ginsenoside Rk1 is a promising new strategy for the treatment of HCC.

Ubiquitin-specific protease 22 promotes tumorigenesis and progression by an FKBP12/mTORC1/autophagy positive feedback loop in hepatocellular carcinoma

Ubiquitin-specific protease 22 (USP22) has been identified as a potential marker for cancer stem cells in hepatocellular carcinoma (HCC). It can promote HCC stemness, which is considered a driver of tumorigenesis. Here, we sought to determine the role of USP22 in tumorigenesis, elucidate its underlying mechanism, and explore its therapeutic significance in HCC. As a result, we found that tissue-specific Usp22 overexpression accelerated tumorigenesis, whereas Usp22 ablation decelerated it in a c-Myc/NRasGV12-induced HCC mouse model and that the mammalian target of rapamycin complex 1 (mTORC1) pathway was activated downstream. USP22 overexpression resulted in increased tumorigenic properties that were reversed by rapamycin in vitro and in vivo. In addition, USP22 activated mTORC1 by deubiquitinating FK506-binding protein 12 (FKBP12) and activated mTORC1, in turn, further stabilizing USP22 by inhibiting autophagic degradation. Clinically, HCC patients with high USP22 expression tend to benefit from mTOR inhibitors after liver transplantation (LT). Our results revealed that USP22 promoted tumorigenesis and progression via an FKBP12/mTORC1/autophagy positive feedback loop in HCC. Clinically, USP22 may be an effective biomarker for selecting eligible recipients with HCC for anti-mTOR-based therapy after LT.

TP53/mTORC1-mediated bidirectional regulation of PD-L1 modulates immune evasion in hepatocellular carcinoma

BACKGROUND

Immunotherapy has facilitated great breakthroughs in the treatment of hepatocellular carcinoma (HCC). However, the efficacy and response rate of immunotherapy are limited and vary among different patients with HCC. TP53 mutation substantially affects the expression of immune checkpoint molecules in multiple cancers. However, the regulatory relationship between programmed death ligand 1 (PD-L1) and TP53 is poorly studied in HCC. We aimed to elucidate the regulatory mechanism of PD-L1 in HCC with different TP53 statuses and to assess its role in modulating immune evasion in HCC.

METHODS

HCC mouse models and cell lines with different TP53 statuses were constructed. PD-L1 levels were detected by PCR, western blotting and flow cytometry. RNA-seqencing, immunoprecipitation, chromatin immunoprecipitation and transmission electron microscopy were used to elucidate the regulatory mechanism in HCC with different TP53 status. HCC mouse models and patient with HCC samples were analyzed to demonstrate the preclinical and clinical significance of the findings.

RESULTS

We report that loss of p53 promoted PD-L1 expression and reduced CD8+ T-cell infiltration in patient with HCC samples and mouse models. Mammalian target of rapamycin (mTOR) pathway was activated in p53-loss-of-function HCC or after knocking down TP53. The transcription factor E2F1 was found to bind to the p53 protein in TP53 wild-type HCC cells, and inhibiting mammalian target of rapamycin complex 1 (mTORC1) disrupted this binding and enhanced E2F1 translocation to the nucleus, where it bound to the PD-L1 promoter and transcriptionally upregulated PD-L1. In p53-loss-of-function HCC cells, autophagosomes were activated after mTORC1 suppression, promoting the degradation of PD-L1 protein. The combination of mTOR inhibitor and anti-PD-L1 antibody enhanced CD8+ T-cell infiltration and tumor suppression in TP53 wild-type HCC mouse models, but no benefit was observed in p53-loss-of-function HCC mouse models. In patients with TP53 wild-type HCC, PD-L1 levels were significantly higher in the high E2F1 group than in the low E2F1 group, and the low E2F1 level group had significantly superior survival.

CONCLUSION

We revealed the bidirectional regulatory mechanism of PD-L1 mediated by TP53/mTORC1 in HCC. The combination of mTOR inhibitor and anti-PD-L1 antibody could be a novel precise immunotherapy scheme for TP53 wild-type HCC.

Achieving tolerance modifies cancer susceptibility profiles in liver transplant recipients

Long-term survival of transplant recipients is significantly impacted by malignancy. We aimed to determine whether calcineurin inhibitor (CNI)-treated recipients converted to and weaned off molecular target of rapamycin inhibitor (mTOR-I) therapy have favorable changes in their molecular profiles in regard to malignancy risk. We performed gene expression profiling from liver biopsy and blood (PBMC) specimens followed by network analysis of key dysregulated genes, associated diseases and disorders, molecular and cellular functions using IPA software. Twenty non-immune, non-viremic patients were included, and 8 of them achieved tolerance. Two comparisons were performed: (1) tolerance time point vs tacrolimus monotherapy and (2) tolerance time point vs sirolimus monotherapy. Upon achieving tolerance, IPA predicted significant activation of DNA damage response (p = 5.40e-04) and inhibition of DNA replication (p = 7.56e-03). Conversion from sirolimus to tolerance showed decrease in HCC (p = 1.30e-02), hepatic steatosis (p = 5.60e-02) and liver fibrosis (p = 2.91e-02) associated genes. In conclusion, this longitudinal study of patients eventually achieving tolerance reveals an evolving molecular profile associated with decreased cancer risk and improved hepatic steatosis and liver fibrosis. This provides a biological rationale for attempting conversion to mTOR-I therapy and tolerance following liver transplantation particularly in patients at higher risk of cancer incidence and progression post-transplant.

mTORi-based immunosuppression reduces HCC recurrence at the expense of increased adverse side effects: A systematic review and meta-analysis

Sirolimus and everolimus are mammalian target of rapamycin inhibitors (mTORi) that can reduce relapse rates following liver transplantation (LT) for hepatocellular carcinoma (HCC). Herein, we performed a systematic review and meta-analysis to investigate the efficacy of mTORi and calcineurin inhibitors (CNI) in reducing HCC recurrence and survival adverse effects (AEs) in HCC patients after LT. Systematic literature searches were conducted using MEDLINE, EMBASE, and Cochrane Library databases up to October 2021. The primary outcomes of interest were tumor recurrence rates and overall survival. The secondary outcomes were the characterization and incidence of AEs. A total of 38 trials involving 10,607 participants was included in the analysis. The incidence of recurrence and overall mortality was significantly lower in the mTORi than in the CNI group (relative ratio [RR]: .78, 95% confidence interval [CI]: .68-.89 and RR: .76, 95% CI: .67-.86, respectively). The incidence of some AEs and complications such as acne, anemia, abnormal healing, dyslipidemia, depression, diarrhea, edema, headache/migraine, hypercholesterolemia, incisional hernia, infection, leukopenia, mouth ulceration, pyrexia, proteinuria, pruritis, rash, and thrombocytopenia were higher in the mTORi than in the CNI group. mTORi reduced the recurrence incidence and overall 5-year mortality rate but increased many other incidences of AEs compared with that by CNI. Therefore, clinicians should be aware of the risks and benefits of mTORi use when managing patients undergoing LT for HCC.

E2F7 promotes mammalian target of rapamycin inhibitor resistance in hepatocellular carcinoma after liver transplantation

The mammalian target of rapamycin (mTOR) pathway is frequently deregulated and has critical roles in cancer progression. mTOR inhibitor has been widely used in several kinds of cancers and is strongly recommended in patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). However, the poor response to mTOR inhibitors due to resistance remains a challenge. Hypoxia-associated resistance limits the therapeutic efficacy of targeted drugs. The present study established models of HCC clinical samples and cell lines resistance to mTOR inhibitor sirolimus and screened out E2F7 as a candidate gene induced by hypoxia and promoting sirolimus resistance. E2F7 suppressed mTOR complex 1 via directly binding to the promoter of the TSC1 gene and stabilizes hypoxia-inducible factor-1α activating its downstream genes, which are responsible for E2F7-dependent mTOR inhibitor resistance. Clinically, low E2F7 expression could be an effective biomarker for recommending patients with HCC for anti-mTOR-based therapies after LT. Targeting E2F7 synergistically inhibited HCC growth with sirolimus in vivo. E2F7 is a promising target to reverse mTOR inhibition resistance. Collectively, our study points to a role for E2F7 in promoting mTOR inhibitor resistance in HCC and emphasizes its potential clinical significance in patients with HCC after LT.

Sirolimus or Everolimus Improves Survival After Liver Transplantation for Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

The effects of mammalian target of rapamycin (mTOR) inhibitors (sirolimus [SRL] and everolimus [EVL]) on survival in liver transplantation (LT) recipients with hepatocellular carcinoma (HCC) remain the subject of intense research. Therefore, we performed this systematic review and meta-analysis to investigate the potential survival benefits of mTOR inhibitors (mTORis). Embase, PubMed, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for all randomized controlled trials (RCTs) and cohort studies investigating effects of SRL or EVL on LT recipients for HCC. The primary outcomes were 1-, 2-, 3-, and 5-year overall survival (OS), and the secondary outcomes were 1-, 2-, and 3-year recurrence-free survival (RFS) and adverse effects. Pooled relative risks (RRs) with 95% confidence interval (CI) were calculated by a fixed or random effects model with Mantel-Haenszel weighting. Subgroup analyses were performed according to crucial clinical characteristics. We also conducted sensitivity analyses to assess the reliability of our findings. A total of 17 studies were included. OS was improved in both RCTs (1 year: RR, 1.04; 95% CI, 1.00-1.08; 2 years: RR, 1.09; 95% CI, 1.02-1.16; 3 years: RR, 1.13; 95% CI, 1.04-1.24; 5 years: RR, 1.13; 95% CI, 1.02-1.26) and cohort studies (1 year: RR, 1.13; 95% CI, 1.06-1.20; 2 years: RR, 1.24; 95% CI, 1.16-1.32; 3 years: RR, 1.24; 95% CI, 1.15-1.34; 5 years: RR, 1.17; 95% CI, 1.10-1.24), with a lower risk of renal toxicity (RR, 0.75; 95% CI, 0.60 to 0.93). The 1-, 2-, and 3-year RFS were also improved. Current evidence indicates that SRL- or EVL-based immunosuppression improves OS and RFS with a lower risk of renal toxicity compared with mTORi-free immunosuppression. Nevertheless, results must be interpreted with caution.

Methylation site APC112043544 as a potential biomarker for post-transplant hepatocellular carcinoma recurrence

Objective: To investigate the prognostic value of DNA methylation of tumor suppressor genes for hepatocellular carcinoma (HCC) recurrence after liver transplantation. Methods: APC gene was selected according to The Cancer Genome Atlas dataset. Tumor tissues and clinical data of 85 HCC patients who received a liver transplantation were retrospectively enrolled and next-generation methylation sequencing was performed. Risk factors were determined using the Cox proportional-hazard-regression model. Results: The APC methylation site (chromosome 5, position 112043544) was an independent predictor of post-transplant HCC recurrence. Patients with hyper-methylated APC112043544 experienced superior recurrence-free survival (p = 0.021) and had a decreased proportion of microvascular invasion (p = 0.017). APC112043544 also predicted recurrence risk in patients beyond selection criteria. Conclusions: APC112043544 methylation may serve as a potential biomarker for post-transplant HCC recurrence.

Efficacy and safety of sirolimus early conversion protocol in liver transplant patients with hepatocellular carcinoma: A single-arm, multicenter, prospective study

Mammalian target of rapamycin (mTOR) inhibitor as an attractive drug target with promising antitumor effects has been widely investigated. High quality clinical trial has been conducted in liver transplant (LT) recipients in Western countries. However, the pertinent studies in Eastern world are paucity. Therefore, we designed a clinical trial to test whether sirolimus can improve recurrence-free survival (RFS) in hepatocellular carcinoma (HCC) patients beyond the Milan criteria after LT. This is an open-labeled, single-arm, prospective, multicenter, and real-world study aiming to evaluate the clinical outcomes of early switch to sirolimus-based regimens in HCC patients after LT. Patients with a histologically proven HCC and beyond the Milan criteria will be enrolled. The initial immunosuppressant regimens are center-specific for the first 4-6 weeks. The following regimens integrated sirolimus into the regimens as a combination therapy with reduced calcineurin inhibitors based on the condition of patients and centers. The study is planned for 4 years in total with a 2-year enrollment period and a 2-year follow-up. We predict that sirolimus conversion regimen will provide survival benefits for patients particular in the key indicator RFS as well as better quality of life. If the trial is conducted successfully, we will have a continued monitoring over a longer follow-up time to estimate indicator of overall survival. We hope that the outcome will provide better evidence for clinical decision-making and revising treatment guidelines based on Chinese population data. Trial register: Trial registered at http://www.chictr.org.cn: ChiCTR2100042869.

Trends of rapamycin in survival benefits of liver transplantation for hepatocellular carcinoma

The proportion of liver transplantation (LT) for hepatocellular carcinoma (HCC) has kept on increasing over the past years and account for 20%-40% of all LT. Post-transplant HCC recurrence is considered the most important factor affecting the long-term survival of patients. The use of different types of immunosuppressive agents after LT is closely associated with an increased risk for HCC recurrence. The most commonly used conventional immunosuppressive drugs include the calcineurin inhibitors tacrolimus (FK506) and mammalian target of rapamycin inhibitor rapamycin (RAPA). Compared with tacrolimus, RAPA may carry an advantage in survival benefit because of its anti-tumor effects. However, no sufficient evidence to date has proven that RAPA could increase long-term recurrence-free survival and its anti-tumor mechanism of combined therapy remains incompletely clear. In this review, we will focus on recent advances in clinical application experience and basic research results of RAPA in patients undergoing LT for HCC to further guide the clinical practice.

Association of phenotypic transformation of circulating tumor cells and early recurrence in patients with hepatocellular carcinoma following liver transplantation

BACKGROUND

CTCs play a critical role in the diagnosis and prognosis of liver cancer. However, there are few studies on whether different types of CTCs can predict the prognosis in patients with HCC following LT.

METHODS

Retrospective data including CTCs detected by the CanPatrolTM platform combined with RNA-ISH were collected and analyzed on 56 patients from December 2016 to December 2019 at the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China.

RESULTS

During the study period, fifty-six patients (51 males, 5 females) were included with an mean age of 52 ± 9 years. The 1-, 2- and 3-year recurrence rates of postoperative interstitial CTC-positive and CTC-negative groups were 21.7% vs 10.8%, 37.5% vs 10.8% and 55.5% vs 10.8%, confirming a statistically significant difference between the 2 groups (p = 0.044). The 1-, 2- and 3-year recurrence rates of the increasing interstitial CTCs group were 25.2%, 36.9% and 66.9%, while 12.6%, 24.4% and 24.4% in the decreasing and unchanged group, indicating a significant difference (p = 0.038).

CONCLUSION

CanPatrolTM platform presents a superior analytical sensitivity, and may be used as a dynamic monitoring tool for CTCs. And interstitial CTCs which are more aggressive and metastatic caused by EMT can be regarded as a predictor of post-transplant tumor recurrence after LT for HCC.

Sirolimus-based immunosuppression improves the prognosis of liver Transplantation Recipients with low TSC1/2 expression in hepatocellular carcinoma beyond the Milan Criteria

BACKGROUND

The use of the immunosuppressive agent sirolimus (SRL) following liver transplantation (LT) in patients with hepatocellular carcinoma (HCC) is controversial. Sirolimus is a typical mammalian target of rapamycin (mTOR) inhibitor, and tuberous sclerosis 1-tuberous sclerosis 2 complex (TSC1/TSC2) is an important negative effector in the mTOR pathway. In this study, we investigated the effect of SRL-based immunosuppression on the prognosis of LT recipients with HCC beyond the Milan criteria based on TSC1/2 expression and explored the effect of TSC1 on HCC in vitro and in vivo.

METHODS

We retrospectively analyzed 120 HCC patients who underwent LT in our hospital between January 1, 2015 and December 30, 2018. All patients had HCC beyond the Milan criteria and were divided into the SRL group (n = 50) and non-SRL group (n = 70). TSC1/2 expression levels in paraffin-embedded tissues were determined by immunohistochemistry (IHC) and then analyzed as subgroups. Overall survival (OS) and disease-free survival (DFS) were analyzed using the Kaplan-Meier method. TSC1 expression was silenced in Huh-7 and Bel-7402 cell lines for further cell function experiments.

RESULTS

88.3% of patients were HBV LT recipients. The SRL group exhibited better DFS and OS compared to the non-SRL group (P = 0.02, P = 0.003). Subgroup (TSC1-based or TSC2-based) analyses revealed that patients with low TSC1 or TSC2 expression benefited from sirolimus (DFS: P = 0.046, OS: P = 0.006 for TSC1; DFS: P = 0.05, OS: P = 0.003 for TSC2) compared with patients with high expression. TSC1 knockdown in Huh-7 and Bel-7402 HCC cell lines activated the mTORC1 pathway and enhanced cell proliferation, migration and sensitivity to SRL in vitro and in vivo.

CONCLUSION

TSC1/2 expression could be used to predict the prognosis of patients with HCC beyond the Milan criteria who underwent SRL-based immunosuppression following LT. TSC1 knockdown promoted HCC malignancy and enhanced sensitivity to SRL.

Impact of treatment modalities on patients with recurrent hepatocellular carcinoma after liver transplantation: Preliminary experience

BACKGROUND

Post-liver transplantation (LT) hepatocellular carcinoma (HCC) recurrence still occurs in approximately 20% of patients and drastically affects their survival. This study aimed to evaluate the efficacy of various treatments for recurrent HCC after LT in a Chinese population.

METHODS

A total of 64 HCC patients with tumor recurrence after LT were enrolled in this study. Univariate and multivariate analyses were performed to identify factors affecting post-recurrence survival.

RESULTS

Of the 64 patients with recurrent HCC after LT, those who received radical resection followed by nonsurgical therapy had a median overall survival (OS) of 20.9 months after HCC recurrence, significantly superior to patients who received only nonsurgical therapy (9.4 months) or best supportive care (2.4 months). The one- and two-year OS following recurrence was favorable for patients receiving radical resection followed by nonsurgical therapy (93.8%, 52.6%), poor for patients receiving only nonsurgical therapy (30.8%, 10.8%), and dismal for patients receiving best supportive care (0%, 0%; overall P < 0.001). Median OS in sorafenib-tolerant patients treated with lenvatinib was 19.5 months, far surpassing the patients that discontinued sorafenib or were treated with regorafenib after sorafenib failure (12 months, P < 0.001). Compared with tacrolimus-based immunosuppressive therapy, OS was significantly increased with sirolimus-based therapy at one and two years after HCC recurrence (P = 0.035). Multivariate analysis showed radical resection combined with nonsurgical therapy for recurrent HCC and sorafenib-lenvatinib sequential therapy were independent favorable factors for post-recurrence survival.

CONCLUSIONS

Aggressive surgical intervention in well-selected patients significantly improves OS after recurrence. A multidisciplinary treatment approach is required to slow down disease progression for patients with unresectable recurrent HCC.