Antineoplastic effects of mammalian target of rapamycine inhibitors

Determinants of immunosuppressive therapy in renal transplant recipients: an Italian observational study (the CESIT project)

BACKGROUND

Very scanty evidence is available on factors influencing the choice of immunosuppressive drug therapy after kidney transplantation.

METHODS

An Italian multiregional real-world study was conducted integrating national transplant information system and claims data. All patients undergoing kidney transplantation for the first time during 2009-2019 (incident patients) were considered. Multilevel logistic models were used to estimate Odds Ratio (OR) and corresponding 95% Confidence intervals. Factors with statistically significance were identified as characteristics associated with treatment regimens: cyclosporin-CsA vs tacrolimus-Tac and, within the latter group, mTOR inhibitors vs mycophenolate-MMF.

RESULTS

We identified 3,622 kidney patients undergoing transplantation in 17 hospitals located in 4 Italian regions, 78.3% was treated with TAC-based therapy, of which 78% and 22% in combination with MMF and mTOR, respectively. For both comparison groups, the choice of immunosuppressive regimens was mostly guided by standard hospital practices. Only few recipient and donor characteristics were found associated with specific regimen (donor/receipt age, immunological risk and diabetes).

CONCLUSIONS

The choice of post-renal transplant immunosuppressive therapy seems to be mostly driven by standard Centre practices, while only partially based on patient's characteristics and recognized international guidelines.

Ganglioglioma, Epilepsy, and Intellectual Impairment due to Familial TSC1 Deletion

BACKGROUND

Tuberous sclerosis complex (TSC) is a multisystem disorder diagnosed by clinical criteria and/or genetic testing. Genetic testing reveals atypical phenotypes that have not met clinical criteria, with practical implications.

METHODS

We describe 4 family members with pathogenic partial deletion in TSC1 who individually did not meet tuberous sclerosis complex clinical criteria.

RESULTS

Family members had different and atypical findings of tuberous sclerosis complex. Although none of the family members fulfilled the clinical criteria for tuberous sclerosis complex, they all carried the same genomic deletion (9q34.13q34.2) that included part of the TSC1 gene. One member had ganglioglioma and intractable seizures, one sibling presented with seizures, developmental delay, and displayed white matter abnormalities; another sibling had no clinical manifestations but has cortical tuber. Their mother has facial angiofibroma, cortical tuber, and seizures during infancy.

CONCLUSIONS

Ganglioglioma may be a phenotypic expression of TSC1. Genetic testing is recommended for infants with brain tumors, especially those with an abnormal familial history.

Evaluation of mTOR signaling pathway proteins in rat gastric mucosa exposed to sulfite and ghrelin

BACKGROUND/AIMS

Mammalian target of rapamycin (mTOR) signaling serves as a central regulator of cell growth, proliferation, and survival. In this study, we planned to evaluate the expressions of mTOR signaling constituents (p-p70S6K, p-mTOR, and p-Tuberin) in rat gastric mucosa and to compare the results in sulfite- and sulfite+ghrelin-exposed groups.

MATERIALS AND METHODS

Rats were divided into three groups: the control group (C), the sodium metabisulfite (Na2S2O5) (S) group, and sulfite+ghrelin (SG) group. Sodium metabisulfite at 100 mg/kg/day was administered via gavage, and ghrelin at 20 μg/kg/day was administered intraperitoneally for 35 days. We have used immunohistochemistry for mTOR signaling pathway components.

RESULTS

There were no significant differences for p-p70S6K and p-mTOR expression among the C, S, and SG groups. Tuberin expression was significantly increased in the S group compared to the C group. Furthermore, tuberin expression was found to be significantly decreased in the SG group.

CONCLUSION

This study is the first one in the literature that shows the expression of mTOR signaling proteins in gastric mucosa of rats exposed to sulfite and ghrelin. Furthermore, it demonstrates that ghrelin treatment reduces p-Tuberin expression induced by ingested sulfite.

Metformin produces growth inhibitory effects in combination with nutlin-3a on malignant mesothelioma through a cross-talk between mTOR and p53 pathways

Background

Mesothelioma is resistant to conventional treatments and is often defective in p53 pathways. We then examined anti-tumor effects of metformin, an agent for type 2 diabetes, and combinatory effects of metformin and nutlin-3a, an inhibitor for ubiquitin-mediated p53 degradation, on human mesothelioma.

Methods

We examined the effects with a colorimetric assay and cell cycle analyses, and investigated molecular events in cells treated with metformin and/or nutlin-3a with Western blot analyses. An involvement of p53 was tested with siRNA for p53.

Results

Metformin suppressed cell growth of 9 kinds of mesothelioma including immortalized cells of mesothelium origin irrespective of the p53 functional status, whereas susceptibility to nutlin-3a was partly dependent on the p53 genotype. We investigated combinatory effects of metformin and nutlin-3a on, nutlin-3a sensitive MSTO-211H and NCI-H28 cells and insensitive EHMES-10 cells, all of which had the wild-type p53 gene. Knockdown of p53 expression with the siRNA demonstrated that susceptibility of MSTO-211H and NCI-H28 cells to nutlin-3a was p53-dependent, whereas that of EHMES-10 cells was not. Nevertheless, all the cells treated with both agents produced additive or synergistic growth inhibitory effects. Cell cycle analyses also showed that the combination increased sub-G1 fractions greater than metformin or nutlin-3a alone in MSTO-211H and EHMES-10 cells. Western blot analyses showed that metformin inhibited downstream pathways of the mammalian target of rapamycin (mTOR) but did not activate the p53 pathways, whereas nutlin-3a phosphorylated p53 and suppressed mTOR pathways. Cleaved caspase-3 and conversion of LC3A/B were also detected but it was dependent on cells and treatments. The combination of both agents in MSTO-211H cells rather suppressed the p53 pathways that were activated by nutrin-3a treatments, whereas the combination rather augmented the p53 actions in NCI-H28 and EHMES-10 cells.

Conclusion

These data collectively indicated a possible interactions between mTOR and p53 pathways, and the combinatory effects were attributable to differential mechanisms induced by a cross-talk between the pathways.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3300-y) contains supplementary material, which is available to authorized users.

Renal Cancer Stem Cells: Characterization and Targeted Therapies

Renal cell carcinoma (RCC) is a major neoplasm with high incidence in western countries. Tumors are heterogeneous and are composed of differentiated cancer cells, stromal cells, and cancer stem cells (CSCs). CSCs possess two main properties: self-renewal and proliferation. Additionally, they can generate new tumors once transplanted into immunodeficient mice. Several approaches have been described to identify them, through the expression of cell markers, functional assays, or a combination of both. As CSCs are involved in the resistance mechanisms to radio- and chemotherapies, several new strategies have been proposed to directly target CSCs in RCC. One approach drives CSCs to differentiate into cancer cells sensitive to conventional treatments, while the other proposes to eradicate them selectively. A series of innovative therapies aiming at eliminating CSCs have been designed to treat other types of cancer and have not been experimented with on RCC yet, but they reveal themselves to be promising. In conclusion, CSCs are an important player in carcinogenesis and represent a valid target for therapy in RCC patients.

Minimization vs tailoring: Where do we stand with personalized immunosuppression during renal transplantation in 2015?

The introduction of novel immunosuppressive agents over the last two decades and the improvement of our diagnostic tools for early detection of antibody-mediated injury offer us an opportunity, if not a mandate, to better match the immunosuppression needs of the individual patients with side effects of the therapy. However, immunosuppressive regimens in the majority of programs remain mostly protocol-driven, with relatively little inter-program heterogeneity in certain areas of the world. Emerging data showing different outcomes with a particular immunosuppressive strategy in populations with varying immunological risks underscore a real potential for “personalized medicine” in renal transplantation. Studies demonstrating marked differences in the adverse-effect profiles of individual drugs including the risk for viral infections, malignancy and renal toxicity call for a paradigm shift away from a “one size fits all” approach to an individually tailored immunosuppressive therapy for renal transplant recipients, assisted by both screening for predictors of graft loss and paying close attention to dose or class-related adverse effects. Our paper explores some of the opportunities during the care of these patients. Potential areas of improvements may include: (1) a thorough assessment of immunological and metabolic risk profile of each renal transplant recipient; (2) screening for predictors of graft loss and early signs of antibody-mediated rejection with donor-specific antibodies, protocol biopsies and proteinuria (including close follow up of adverse effects with dose adjustments or conversions as necessary); and (3) increased awareness of the possible link between poor tolerance of a given drug at a given dose and non-adherence with the prescribed regimen. Altogether, these considerations may enable the most effective use of the drugs we already have.

Risk of fatigue and hepatic and metabolic toxicities in patients with solid tumors treated with everolimus: a meta-analysis

ABSTRACT 

Background: We performed a systematic review and meta-analysis of fatigue, hepatic and metabolic toxicities associated with everolimus intake in patients with solid tumors. Methods: Eligible studies included randomized trials of patients with solid tumors on everolimus describing events of fatigue, hyperlipidemia, hyperglycemia and elevated alanine aminotransferase (ALT). Results: After the exclusion of ineligible studies, a total of ten clinical trials were considered eligible for the meta-analysis. The relative risks of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT were 1.31 (p < 0.002), 3.06 (p < 0.0001), 2.54 (p = 0.0001) and 2.96 (p < 0.003), respectively. Conclusion: Our meta-analysis demonstrates that everolimus is associated with a significantly increased risk of all-grade fatigue, hyperglycemia, hyperlipidemia and elevated ALT.

Mammalian Target of Rapamycin Inhibitors Resistance Mechanisms in Clear Cell Renal Cell Carcinoma

Mammalian target of rapamycin (mTOR) is a kinase protein involved in PI3K/AKT signaling with a central role in the processes of cell growth, survival and angiogenesis. Frequent mutations of this pathway make upstream and downstream components novel targets for tailored therapy design. Two mTOR inhibitors - everolimus and temsirolimus - enable an increase in overall survival (OS) or progression-free survival (PFS) time in a treatment of renal cancer. Despite recent advances in renal cancer treatment, resistance to targeted therapy is common. Understanding of molecular mechanisms is the basis of drug resistance which can facilitate prediction of success or failure in combinational or sequential targeted therapy. The article provides current knowledge on the mTOR signaling network and gives insight into the mechanisms of resistance to mTOR inhibitors from the complex perspective of RCC biology. The mechanisms of resistance developed not only by cancer cells, but also by interactions with tumor microenvironment are analyzed to emphasize the role of angiogenesis in ccRCC pathogenesis. As recent studies have shown the role of PI3K/AKT-mTOR pathway in proliferation and differentiation of cancer stem cells, we discuss cancer stem cell hypothesis and its possible contribution to ccRCC resistance. In the context of drug resistance, we also elaborate on a new approach considering ccRCC as a metabolic disease. In conclusion we speculate on future developments in agents targeting the mTOR pathway taking into consideration the singular biology of ccRCC.

Risk of mucocutaneous toxicities in patients with solid tumors treated with everolimus; a systematic review and meta-analysis

BACKGROUND

We performed a systematic review and meta-analysis of mucocutaneous toxicities associated with the use of everolimus in solid tumors.

PATIENTS AND METHODS

Eligible studies included randomized Phase II and III trials of patients with solid tumors on everolimus; describing events of stomatitis, skin rash, pruritus and mouth ulceration.

RESULTS

Our search strategy yielded 380 potentially relevant citations on everolimus from Pubmed/Medline, CENTRAL Cochrane registry and American Society of Clinical Oncology meeting library. After exclusion of ineligible studies, a total of 10 clinical trials were considered eligible for the meta-analysis, including eight Phase III trials and two Phase II trials. The relative risk of all-grade stomatitis, skin rash, pruritus and mouth ulceration were 3.86(95% CI: 2.23-6.68; p < 0.001); 3.49(95% CI: 2.39-5.08; p < 0.0001); 2.85(95% CI: 2.04-3.97; p = 0.0001); 3.31 (95% CI: 1.46-7.50; p = 0.004); respectively. Exploratory subgroup analysis showed no effect of tumor types or treatment regimen on the relative risk of the relevant adverse events.

CONCLUSION

Our meta-analysis has demonstrated that everolimus is associated with a significantly increased risk of all-grade stomatitis, skin rash, and pruritus and mouth ulceration. Clinicians should be aware of these risks and perform early clinical assessment and intervene accordingly.

Liver transplantation for malignancy: Current treatment strategies and future perspectives

In 1967, Starzl et al performed the first successful liver transplantation for a patient diagnosed with hepatoblastoma. In the following, liver transplantation was considered ideal for complete tumor resection and potential cure from primary hepatic malignancies. Several reports of liver transplantation for primary and metastatic liver cancer however showed disappointing results and the strategy was soon dismissed. In 1996, Mazzaferro et al introduced the Milan criteria, offering liver transplantation to patients diagnosed with limited hepatocellular carcinoma. Since then, liver transplantation for malignant disease is an ongoing subject of preclinical and clinical research. In this context, several aspects must be considered: (1) Given the shortage of deceased-donor organs, long-term overall and disease free survival should be comparable with results obtained in patients transplanted for non-malignant disease; (2) In this regard, living-donor liver transplantation may in selected patients help to solve the ethical dilemma of optimal individual patient treatment vs organ allocation justice; and (3) Ongoing research focusing on perioperative therapy and anti-proliferative immunosuppressive regimens may further reduce tumor recurrence in patients transplanted for malignant disease and thus improve overall survival. The present review gives an overview of current indications and future perspectives of liver transplantation for malignant disease.