Sirolimus Prolongs Survival after Living Donor Liver Transplantation for Hepatocellular Carcinoma Beyond Milan Criteria: A Prospective, Randomised, Open-Label, Multicentre Phase 2 Trial

mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

Targeting EGFR/PI3K/AKT/mTOR Signaling in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) poses a significant global health concern, with its incidence steadily increasing. The development of HCC is a multifaceted, multi-step process involving alterations in various signaling cascades. In recent years, significant progress has been made in understanding the molecular signaling pathways that play central roles in hepatocarcinogenesis. In particular, the EGFR/PI3K/AKT/mTOR signaling pathway in HCC has garnered renewed attention from both basic and clinical researchers. Preclinical studies in vitro and in vivo have shown the effectiveness of targeting the key components of this signaling pathway in human HCC cells. Thus, targeting these signaling pathways with small molecule inhibitors holds promise as a potential therapeutic option for patients with HCC. In this review, we explore recent advancements in understanding the role of the EGFR/PI3K/AKT/mTOR signaling pathway in HCC and assess the effectiveness of targeting this signaling cascade as a potential strategy for HCC therapy based on preclinical studies.

Does mtori base immunosuppression offer survival advantage after liver transplantation for hepatocellular carcinoma? Systematic review and meta-analysis of randomized controlled trials

Recurrence is still a problem after liver transplant for hepatocellular carcinoma (HCC). We performed an updated systematic review and meta-analysis of randomized controlled trials comparing tumor recurrence of mammalian target of rapamycin inhibitors (mTORi) versus Calcineurin inhibitor-based immunosuppression after liver transplantation for HCC. A systematic search was conducted in the following databases: MEDLINE, EMBASE, and Cochrane Central Register of Control Trials databases. The Medical Subject Headings used in the search included: "sirolimus," "everolimus," "mTORi," "HCC," "mTORi," "hepatic transplantation" "randomized controlled trials," and "liver transplantation (LT)". Seven randomized controlled trials were included for meta-analysis. There were a total of 1,365 patients, with 712 of these patients receiving calcineurin inhibitors (CNIs) while 653 had received mTORi. Our meta-analysis revealed that patients that received mTORi-based immunosuppression had superior recurrence-free survival (RFS) at 1 year and 3 years with a hazard ratio of 2.02 and 1.36, respectively. Meta-analysis also showed that within the first 3 years after LT for HCC, patients receiving CNIs-based immunosuppression have a higher recurrence than those receiving mTORi-based immunosuppression. Our meta-analysis revealed that recipients of mTORi-based immunosuppression had a superior OS at 1 year and 3 years. mTORi-based immunosuppression is associated with decreased early recurrence and improved RFS and overall survival.

Sirolimus vs tacrolimus: Which one is the best therapeutic option for patients undergoing liver transplantation for hepatocellular carcinoma?

Liver transplantation (LT) withstands as the most preferred therapeutic option for patients afflicted with hepatocellular carcinoma (HCC) and cirrhosis. To improve prognosis post-transplant, as well as to prevent the occurrence of rejection, a life-long immunosuppression strategy is implemented. The following letter to the editor highlights and provides novel evidence from recently published literature on topics discussed within the review article titled “Trends of rapamycin in survival benefits of liver transplantation for hepatocellular carcinoma” in World J Gastrointest Surg 2021; 13: 953-966. In the recent manuscript, the authors compared immunosuppressive drugs such as the newer option first-generation mammalian target of rapamycin inhibitor, also known as sirolimus, with the most widely used first-generation calcineurin inhibitors, such as tacrolimus (TAC). TAC is commonly known as the most effective immunosuppressive drug after LT, but it has been reported to cause intolerable side effects such as nephrotoxicity, neurotoxicity, diabetes, hypertension, gastrointestinal disturbances, increased risk of infections, and malignancies. It is necessary for physicians to be aware of recent advances in tacrolimus and sirolimus therapies to compare and understand distinctly the effectiveness and tolerability of these drugs. This will assist clinicians in making the best treatment decisions and improve the clinical prognosis of LT recipients with HCC.

Sirolimus Attenuates Calcineurin Inhibitor-Induced Epithelial-Mesenchymal Transition in Hepatocellular Carcinoma

BACKGROUND

Calcineurin inhibitors (CNIs), which are potent immunosuppressants (ISs), increase the risk for hepatocellular carcinoma (HCC) recurrence after liver transplantation (LTx). Epithelial-mesenchymal transition (EMT) is a key process in which epithelial cancer cells lose their polarity, resulting in cancer progression and metastasis. The aim of this study was to evaluate the effect of sirolimus (SRL) individually and in combination with other ISs to reduce EMT.

METHODS

HCC SK-Hep1 cells were used and various ISs (SRL, tacrolimus, cyclosporine A, or mycophenolate mofetil) were administered at 2 dosages and in combination therapies. Mice were transplanted with SK-Hep1 cells (in the liver) and were monitored after 2 weeks.

RESULTS

The in vitro treatment with SRL showed a dose-dependent attenuation of cell proliferation and migration in case of the individual and IS combination treatments; further, decreased levels of pro-EMT proteins, namely, N-cadherin, transforming growth factor-β, ZEB1, Slug, and Snail were observed. In contrast, E-cadherin expression was upregulated after both the individual and IS combination treatments. These results were also observed in the samples from mice transplanted with the SK-Hep1 cells.

CONCLUSION

The present study demonstrated that SRL reduced HCC metastasis by inhibiting EMT. Thus, our findings provide a rationale for the use of SRL in combination with ISs in HCC LTx patients.

Outcomes of Living Donor Liver Transplantation in Patients With a History of Ruptured Hepatocellular Carcinoma

Background: Liver transplantation (LT) is considered a contraindication in patients with a history of hepatocellular carcinoma (HCC) rupture because ruptured HCCs are classified as T4 in the current American Joint Committee on Cancer TNM system. This study aimed to assess living donor liver transplantation (LDLT) in these patients and elucidate the factors that may have affected their outcomes.

Methods: Data of patients with a history of ruptured HCC who underwent LDLT between January 1999 and December 2019 were retrospectively reviewed.

Results: Among 789 patients who underwent LDLT for HCC, five (0.64%) had a history of HCC rupture. Three patients (60%) were treated with transarterial chemoembolization (TACE) or transarterial embolization (TAE) for hemostasis, and two patients (40%) achieved spontaneous hemostasis. One of two patients who achieved spontaneous hemostasis underwent surgical resection and LT at 1 week and 6 years after the rupture, respectively. The other patient underwent LT 2 days after the rupture. Four patients (80%) survived for >5 years, while two patients (40%) experienced recurrence and succumbed during the median follow-up duration of 85.3 months (range, 12.4–182.7). The recurrence first developed at 4.3 and 17.0 months after LT; these patients were managed well using surgical resection for peritoneal seeding and TACE for intrahepatic HCC.

Conclusion: LDLT can be considered a treatment method even in patients with a history of HCC rupture after full evaluation of tumor biology and risk of recurrence.

Distribution evaluation of tacrolimus in the ascitic fluid of liver transplant recipients with liver cirrhosis by a sensitive ultra-performance liquid chromatography-tandem mass spectrometry method

Tacrolimus has a narrow therapeutic index and large individual differences in pharmacokinetics. The distribution of tacrolimus in ascitic fluid and its influence on whole-blood tacrolimus were unclear. In this study, a sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was established and validated for the quantification of tacrolimus in the ascitic fluid of liver transplant recipients. Chromatographic separation was achieved on an Agilent ZORBAX Eclipse Plus Phenyl-Hexyl column (2.1 × 100 mm, 3.5 μm). Mass spectrometry was performed in multiple reaction monitoring conditions of transitions m/z 821.4→768.5 for tacrolimus. The concentrations of tacrolimus in the ascitic fluid range from 0.2 to 3.0 ng/mL, accounting for 1.19-31.87% of whole-blood tacrolimus concentrations. A linear mixed model showed a statistically significant positive correlation between the steady-state trough blood concentration of tacrolimus and the corresponding amount of tacrolimus excreted in the ascitic fluid for 24 consecutive hours, especially after normalization by daily dose per unit body weight. These data suggested that the distribution of tacrolimus in the ascitic fluid has great individual differences. The whole-blood tacrolimus concentration, dose per unit body weight, and other confounding factors may contribute to the excretion of tacrolimus in ascitic fluid, but the influence of tacrolimus excretion in drained ascitic fluid on the whole-blood tacrolimus concentration is negligible.

The Importance of the Immunosuppressive Regime on Hepatocellular Carcinoma Recurrence After Liver Transplantation

PURPOSE

Hepatocellular carcinoma (HCC) recurrence after liver transplantation (LT) occurs in approximately 20% of recipients and these patients have median about one year survival after diagnosis. Some immunosuppressive drugs can cause development of HCC recurrence, on the other hand some immunosuppressive drugs may have a positive effect for preventing HCC recurrence. Thus, immunosuppression (IS) modification may play a role in preventing HCC recurrence.

METHODS

In this review, we analyzed IS treatment strategy in two parts: before HCC recurrence following LT and after HCC recurrence following LT, and after HCC recurrence following LT.

RESULTS

There is no proven, optimal IS protocol to prevent HCC recurrence after transplantation. Therefore, individualized immunosuppressive treatments should be tailored to the biological behaviour of HCC. Forcing the immune tolerance in terms of recurrence can probably be expressed as the most appropriate post LT period. Once HCC recurrence has developed after transplantation, again, there is no commonly accepted, optimal IS treatment, but there is a tendency to switch to IS modifications that include mTORi by minimizing CNIs and MMF.

CONCLUSION

There is a need for well-designed, randomized, controlled clinical studies with larger numbers of patients on this subject.

Real-Life Experience of mTOR Inhibitors in Liver Transplant Recipients in a Region Where Living Donation Is Predominant

Background: Mammalian target of rapamycin (mTOR) inhibitors, such as everolimus and sirolimus, may be efficacious in preserving renal function in liver transplantation (LT) recipients while preventing hepatocellular carcinoma (HCC) recurrence.

Materials and Methods: In this study, we retrospectively evaluated the safety, efficacy, and renoprotective effects of mTOR inhibitors in LT recipients. Among the 84 patients enrolled, mTOR inhibitor was commenced during the first year after LT. Renal function was measured by estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease equation.

Results: Regarding the type of mTOR inhibitor, everolimus was used in 71 patients and sirolimus in 13 patients. Concomitant tacrolimus was used in 63 patients (75.0%). For total enrolled patients, kidney function did not significantly change during 12 months after initiation of mTOR inhibitors, although tacrolimus-withdrawn patients (n = 21) showed better kidney function compared to tacrolimus-minimized patients (n = 63) after conversion. However, a significant improvement in kidney function was observed in the eGFR <60 ml/min/1.73 m2 group (n = 19) 12 months after initiation of mTOR inhibitors, for both patient groups with early + mid starters (n = 7, stating within 1 year after LT) and late starters (n = 12, starting over 1 year after LT). mTOR inhibitors were safely administered without serious adverse events that led to drug discontinuation.

Conclusion: We demonstrated that patients with renal impairment showed significant improvement in renal function regardless of the timing of mTOR inhibitor start, suggesting that switch to mTOR inhibitors may be beneficial when renal function declines.