Expert consensus on the clinical application of PI3K/AKT/mTOR inhibitors in the treatment of advanced breast cancer

Phosphoinositide 3‐kinase(PI3K)/protein kinase B(PKB or AKT)/mammalian target of rapamycin(mTOR)signaling pathway(PAM pathway)plays an important role in the development of breast cancer and are closely associated with the resistance to endocrine therapy in advanced breast cancer.Therefore,anticancer treatment targeting key molecules in this signaling pathway has become a research hotspot in recent years.Randomized clinical trials have demonstrated that PI3K/AKT/mTOR inhibitors bring significant clinical benefit to patients with advanced breast cancer,especially to those with hormone receptor(HR)‐positive,human epidermal growth factor receptor(HER)2‐negative advanced breast cancer.Alpelisib,a PI3K inhibitor,and everolimus,an mTOR inhibitor,have been approved by FDA.Based on their high efficacy and relatively good safety profile,an expanded indication of everolimus in breast cancer has been approved by National Medical Products Administration(NMPA).Alpelisib is expected to be approved in China in the near future.The members of the consensus expert panel reached this consensus to comprehensively define the role of PI3K/AKT/mTOR signaling pathway in breast cancer,efficacy and clinical applications of PI3K/AKT/mTOR inhibitors,management of adverse reactions,and PIK3CA mutation detection,to promote the understanding of PI3K/AKT/mTOR inhibitors for Chinese oncologists,improve clinical decision‐making,and prolong the survival of target patient population.

Structure-based design and biological evaluation of novel mTOR inhibitors as potential anti-cervical agents

The mammalian target of rapamycin(mTOR) is a critical component of the PI3K-AKT signaling pathway. It is highly activated in cervical cancer, which continues to pose an important clinical challenge with an urgent need for new and improved therapeutic approaches. Herein, we describe the structure-based drug discovery and biological evaluation of a series of m TOR kinase inhibitors as potential anti-cervical cancer agents. The results of enzymatic activity assays supported C3 as a potential m TOR inhibitor, which exhibited high inhibitory activity with an IC50 of 1.57 μM. Molecular docking and dynamics simulation were conducted to predict the binding patterns, suggesting relationships between structure and activity. The anti-proliferative assay against diverse cancer cell lines was displayed subsequently, revealing that C3 exhibited significant proliferation inhibition against cervical cancer cell He La(IC50=0.38μM) compared with other cell lines. Moreover, C3 could effectively reduce the expression of phospho-ribosomal S6 protein(p-S6) in He La cells in a dose-dependent manner. Noteworthily, m TOR signaling and other cellular pathways might contribute to the significant effect of C3 against cervical cancer simultaneously. These data indicated that C3 represented a good lead molecule for further development as a therapeutic agent for cervical cancer treatment.

Early use of mTOR inhibitors-based immunosuppression in heart transplantation recipients: a systematic review and meta-analysis of randomized controlled trials

The aim of our study is to assess the efficacy and safety of early use of m TOR inhibitors-based immunosuppression compared with standard immunosuppression in heart transplantation recipients. We reviewed eight randomized controlled trials identified from Medline/Pub Med, Embase, web of science, Transplant Library and Cochrane Library to evaluate the effects of m TOR inhibitors therapy on outcomes of biopsy-proven acute rejection,acute rejection associated with hemodynamic compromise, death, cytomegalovirus infection, post-transplant malignancy, cardiac allograft vasculopathy, maximal intimal thickness and renal function. Meta-analysis including 2066recipients showed a significantly lower incidence of biopsy-proven acute rejection, cytomegalovirus infection, cardiac allograft vasculopathy and decreased maximal intimal thickness change. In conclusion, our meta-analysis suggested that early use of m TOR inhibitors-based immunosuppression were more effective and safer compared with standard immunosuppression in heart transplant recipients, especially in reducing acute rejection, cytomegalovirus infection, cardiacallograft vasculopathy and preserving renal function when combined with reduced calcineurin inhibitors.

Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors

CDK4/6 inhibitors are the standard treatment in advanced HR+/HER2-breast cancer patients.Nevertheless,the resistance to CDK4/6 inhibitors is inevitable and the strategies to overcome resistance are of great interest.Here,we show that the palbociclibresistant breast cancer cells expressed significantly higher levels of Cyclin D1 and CDK4 proteins because of upregulated protein synthesis.Silencing Cyclin D1 or CDK4 led to cell cycle arrest while silencing Cyclin E1 or CDK2 restored the sensitivity to palbociclib.Furthermore,PI3K/mTOR pathway was hyper-activated in palbociclib-resistant cells,leading to more phosphorylated 4E-BP1 and higher levels of Cyclin D1 and CDK4 translation.Targeting PI3K/mTOR pathway with a specific PI3Kαinhibitor(BYL719)or an mTOR inhibitor(everolimus)reduced the protein levels of Cyclin D1 and CDK4,and restored the sensitivity to palbociclib.The tumor samples expressed significantly higher levels of Cyclin D1,CDK4,p-AKT and p-4E-BP1 after progression on palbociclib treatment.In conclusion,our findings suggest that overexpressed Cyclin D1 and CDK4 proteins lead to the resistance to CDK4/6 inhibitor and PI3K/mTOR inhibitors are able to restore the sensitivity to CDK4/6 inhibitors,which provides the biomarker and rationale for the combinational use of CDK4/6 inhibitors and PI3K/mTOR inhibitors after CDK4/6 inhibitor resistance in breast cancer.

Mediation of Anti-Keloid Effects of mTOR Inhibitors by Autophagy-Independent Machinery

Objective:Blocking mechanistic target of rapamycin(mTOR)activation with mTOR inhibitors has promising therapeutic potential for keloids.However,the precise mechanism of mTOR inhibitors remains unclear.This study was aimed to investigate the role of autophagy machinery in the anti-keloid effects of mTOR inhibitors.Methods:We first validated the biological effects induced by the mTOR inhibitors rapamycin(100 nmol/L)and KU-0063794(5μmol/L)on the proliferation,apoptosis,migration,and collagen synthesis of keloid fibroblasts(KFs)derived from Han Chinese persons through a Cell Counting Kit-8 assay,5-Bromo-2’-deoxyuridine incorporation,Annexin V/propidium iodide staining,migration,and western blotting.To explore whether autophagy machinery is involved in the anti-keloid effects of mTOR inhibitors,we first blocked the autophagy activation induced by rapamycin and KU-0063794 with a pharmacological autophagy inhibitor(wortmannin)or by silencing the key autophagy gene(ATG5),and we then re-evaluated these biological effects on KFs.Results:Blocking mTOR activation with either rapamycin or KU-0063794 completely inhibited proliferation,migration,and collagen synthesis of primary KFs but did not affect apoptosis.Incubating KFs with the autophagy inhibitor wortmannin or performingATG5 silencing abrogated the subsequent activation of autophagic activity induced by rapamycin(rapamycin+E-64d+pepstatinvs.rapamycin+wortmannin+E-64d+pepstatin:1.88±0.38vs.1.02±0.35,F=6.86,P=0.013),(non-sense control+rapamycinvs.ATG5 small interfering RNA+rapamycin:1.46±0.18vs.0.75±0.20,respectively;F=7.68,P=0.01)or KU-0063794(KU-0063794+E-64d+pepstatinvs.KU-0063794+wortmannin+E-64d+pepstatin:1.65±0.35vs.0.76±0.17,F=10.01,P=0.004),(NC+KU-0063794vs.ATG5 small interfering RNA+KU-0063794:1.59±0.50vs.0.77±0.09,F=5.93,P=0.02)as evidenced by decreased accumulation of LC3-II.However,blockage of autophagy induction in mTOR inhibitor-treated KFs with both methods did not disturb their anti-keloid effects,such as inhibition of cell viability,cell migration,and collagen synthesis(P>0.05 each).Conclusion:Blocking mTOR activation with the mTOR inhibitors rapamycin and KU-0063794 showed anti-keloid effects in KFs.Restoration of autophagy inhibition by mTOR inhibitors does not contribute to their anti-keloid effects.

Synthesis and Biological Activity of Imidazo[4,5-c]quinoline Derivatives as PI3K/mTOR Inhibitors

A series of mtidazo[4,5-c]qumoline derivatives（12a-12m） was synthesized with 2-amino-5-bromoben- zoic acid and 4-nitrophenylacetonitrile as starting materials, 6-bromo-4-chloro-3-nitroquinoline as intermediate and Suzuki reaction and closure of the imidazolinone ring with triphosgene as key steps. The structures of the key intermediate and target compounds were confirmed by means of 1H NMR, 13C NMR and HRMS. These compounds show an interesting kinase profile as dual PI3K/mTOR tool compounds.

Current cancer therapies and their influence on glucose control

This review focuses on the development of hyperglycemia arising from widely used cancer therapies spanning four drug classes.These groups of medications were selected due to their significant association with new onset hyperglycemia,or of potentially severe clinical consequences when present.These classes include glucocorticoids that are frequently used in addition to chemotherapy treatments,and the antimetabolite class of 5-fluorouracil-related drugs.Both of these classes have been in use in cancer therapy since the 1950s.Also considered are the phosphatidyl inositol-3-kinase(PI3K)/AKT/mammalian target of rapamycin(mTOR)-inhibitors that provide cancer response advantages by disrupting cell growth,proliferation and survival signaling pathways,and have been in clinical use as early as 2007.The final class to be reviewed are the monoclonal antibodies selected to function as immune checkpoint inhibitors(ICIs).These were first used in 2011 for advanced melanoma and are rapidly becoming widely utilized in many solid tumors.For each drug class,the literature has been reviewed to answer relevant questions about these medications related specifically to the characteristics of the hyperglycemia that develops with use.The incidence of new glucose elevations in euglycemic individuals,as well as glycemic changes in those with established diabetes has been considered,as has the expected onset of hyperglycemia from their first use.This comparison emphasizes that some classes exhibit very immediate impacts on glucose levels,whereas other classes can have lengthy delays of up to 1 year.A comparison of the spectrum of severity of hyperglycemic consequences stresses that the appearance of diabetic ketoacidosis is rare for all classes except for the ICIs.There are distinct differences in the reversibility of glucose elevations after treatment is stopped,as the mTOR inhibitors and ICI classes have persistent hyperglycemia long term.These four highlighted drug categories differ in their underlying mechanisms driving hyperglycemia,with clinical presentations ranging from potent yet transient insulin resistant states[type 2 diabetes mellitus(T2DM)-like]to rare permanent insulin-deficient causes of hyperglycemia.Knowledge of the relative incidence of new onset hyperglycemia and the underlying causes are critical to appreciate how and when to best screen and treat patients taking any of these cancer drug therapies.

Neurologic orphan diseases:Emerging innovations and role for genetic treatments

Orphan diseases are rare diseases that affect less than 200000 individuals within the United States.Most orphan diseases are of neurologic and genetic origin.With the current advances in technology,more funding has been devoted to developing therapeutic agents for patients with these conditions.In our review,we highlight emerging options for patients with neurologic orphan diseases,specifically including diseases resulting in muscular deterioration,epilepsy,seizures,neurodegenerative movement disorders,inhibited cognitive development,neuron deterioration,and tumors.After extensive literature review,gene therapy offers a promising route for the treatment of neurologic orphan diseases.The use of clustered regularly interspaced palindromic repeats/Cas9 has demonstrated positive results in experiments investigating its role in several diseases.Additionally,the use of adeno-associated viral vectors has shown improvement in survival,motor function,and developmental milestones,while also demonstrating reversal of sensory ataxia and cardiomyopathy in Friedreich ataxia patients.Antisense oligonucleotides have also been used in some neurologic orphan diseases with positive outcomes.Mammalian target of rapamycin inhibitors are currently being investigated and have reduced abnormal cell growth,proliferation,and angiogenesis.Emerging innovations and the role of genetic treatments open a new window of opportunity for the treatment of neurologic orphan diseases.

Clinical analysis of patients with hepatocellular carcinoma recurrence after living-donor liver transplantation

AIM: To evaluated patterns and outcomes of hepatocellular carcinoma (HCC) recurrence after living donor liver transplantation (LDLT).METHODS: From 2001 to 2014, 293 patients underwent LDLT for HCC at our transplant center. We retrospectively reviewed 54 (18.4%) patients with HCC recurrence after LDLT. We evaluated patterns and outcomes of HCC recurrence after LDLT, with particular attention to the Milan criteria at transplantation, treatments for HCC-recurrent patients, and factors related to survival after HCC recurrence. Furthermore, we evaluated the efficacy of combination treatment of sorafenib and an mTOR inhibitor.RESULTS: The 1-, 2-, and 3-year overall survival rates after HCC recurrence were 41.1%, 20.5%, and 15.4%, respectively. The median time interval between LDLT and HCC recurrence was 6.5 mo. Although recurrence rates according to the Milan criteria at LDLT were significantly different, HCC recurrence patterns and survival rates after HCC recurrence were not significantly different between the two groups. Time to recurrence < 12 mo (P = 0.048), multiple recurrences at HCC recurrence (P = 0.038), and palliative treatment for recurrent tumors (P = 0.003) were significant independent prognostic factors for poor survival after HCC recurrence in a multivariate analysis. The combination treatment of sorafenib and sirolimus showed survival benefits in the palliative treatment group (P = 0.005).CONCLUSION: Curative treatment for recurrent HCC after LDLT is the most important factor in survival rates after HCC recurrence and combination treatments of sorafenib and an mTOR inhibitor could have survival benefits in patients with HCC recurrence after LT in the palliative treatment group.

Tuberous sclerosis patient with neuroendocrine carcinoma of the esophagogastric junction:A case report

BACKGROUND Tuberous sclerosis complex(TSC)is a rare inherited disease with non-cancerous tumor growths in the skin,brain,kidneys,heart,and lungs.The co-occurrence of neuroendocrine neoplasm(NEN)with TSC is even rarer.There have been few reports on the relationship between TSC and neuroendocrine tumors(NETs),and fewer on the relationship between TSC and neuroendocrine carcinoma(NEC),a subtype of NEN.This is the first reported case of NEC occurring at the esophagogastric junction in a patient with TSC.CASE SUMMARY A 46-year-old woman visiting our hospital for the treatment of TSC was admitted to the emergency department with tarry stools and dizziness.Computed tomography scans revealed thickness of the gastric cardia,multiple metastatic lesions of the liver,and enlarged lymph nodes near the lesser curvature of the stomach.Esophagogastroduodenoscopy revealed a type 3 tumor located from the esophagogastric junction to the fundus,and the pathological diagnosis by biopsy was NEC.The patient was treated with seven courses of cisplatin+irinotecan,followed by eight courses of ramucirumab+nab-paclitaxel,one course of nivolumab,and two courses of S-1+oxaliplatin.Twenty-three months after the first treatment,the patient died because of disease progression and deterioration of the general condition.CONCLUSION This case of NEC occurring in a patient with TSC indicates a difference in the occurrence of NETs and NECs.

Everolimus halts hepatic cystogenesis in a rodent model of polycystic-liver-disease

AIM To develop a MRI-based method for accurate determination of liver volume(LV) and to explore the effect of long-term everolimus(EVR) treatment on LV in PCK rats with hepatomegaly. METHODS Thirty-one female PCK rats(model for polycystic-liverdisease: PCLD) were randomized into 3 groups and treatment was started at 16 wk, at the moment of extensive hepatomegaly(comparable to what is done in the human disease). Animals received: controls(n = 14), lanreotide(LAN: 3 mg/kg per 2 wk)(n = 10) or everolimus(EVR: 1 mg/kg per day)(n = 7). LV was measured at week 16, 24, 28. At week 28, all rats were sacrificed and liver tissue was harvested. Fibrosis was evaluated using quantitative image analysis. In addition, gene(quantitative RT-PCR) and protein expression(by Western blot) of the PI3K/Ak T/m TOR signaling pathway was investigated. RESULTS LV determination by MRI correlated excellent with the ex vivo measurements(r = 0.99, P < 0.001). The relative changes in LV at the end of treatment were:(controls) +31.8%;(LAN) +5.1% and(EVR) +8.8%, indicating a significantly halt of LV progression compared with controls(respectively, P = 0.01 and P = 0.04). Furthermore, EVR significantly reduced the amount of liver fibrosis(P = 0.004) thus might also prevent the development of portal hypertension. There was no difference in phosphorylation of Akt(Threonine 308) between LAN-treated PCK rats control PCK rats, whereas S6 was significantly more phosphorylated in the LAN group. Phosphorylation of Akt was not different between controls and EVR treated rats, however, for S6 there was significantly less phosphorylation in the EVR treated rats. Thus, both drugs interact with the PI3K/Ak T/m TOR signaling cascade but acting at different molecular levels.CONCLUSION Everolimus halts cyst growth comparable to lanreotide and reduces the development of fibrosis. m TORinhibition should be further explored in PCLD patients especially those that need immunosuppression.

1 T moderate intensity static magnetic field affects Akt/mTOR pathway and increases the antitumor efficacy of m TOR inhibitors in CNE-2Z cells

Static magnetic field （SMF） has been known to affect cell proliferation in a cell-type-dependent manner, while the mechanism still remains unclear. We found that 1 T moderate intensity SMF inhibits cell proliferation of nasopharyngeal carcinoma CNE-2Z cells and the Akt/ mTOR signaling pathway, which is upregulated in many cancers, roTOR inhibitors are potential chemodrugs, but their clinical effects are limited by the feedback reactiva- tion of other signaling components such as EGFR and Akt. We showed that 1 T SMF increases the antitumor efficacy of mTOR inhibitor Torin 2. In addition, 1 T SMF increases the inhibition efficiency on roTOR substrates phosphorylation and represses the mTOR inhibitor-induced feedback reactivation of EGFR and Akt. Our study not only demonstrates that mTOR/Akt pathway is one of the molecular targets of SMFs in cells, but also reveals the clinical potentials of combinations of roTOR inhibitors and SMFs in cancer treatment.

Progress in targeted therapy for metastatic renal cell carcinoma

In recent years, with the deepening of research on the pathogenesis of renal cell carcinoma, anti-VEGF receptor inhibitors and mTOR inhibitors have been produced, making metastatic renal cell carcinoma into the era of targeted therapy. This article analyzes the latest research results at home and abroad. For patients with metastatic renal cell carcinoma, sunitinib and pizopanib are the first choice for targeted drugs. The drug dose starts from the standard dose, and the disease can be increased as appropriate when the disease progresses;When responding, it should be treated or reduced in time. When using an anti-VEGF inhibitor, the patient's blood pressure should be closely monitored. When the patient has high blood sugar or diabetes, anti-VEGF inhibitors should be preferred.

Sirolimus can promote the disappearance of renal angiomyolipoma associated with tuberous sclerosis complex:a prospective cohort study

Background Renal angiomyolipoma(RAML)is the most common kidney lesion in patients with tuberous sclerosis complex(TSC),affecting about 80%of patients.It is a benign tumor that grows over time,usually bilaterally,and can easily lead to kidney complications such as acute hemorrhage.Herein,we investigated the efficacy and safety of sirolimus in children with TSC-associated RAML and explored the factors affecting tumor disappearance under sirolimus treatment through subgroup analysis.Methods A prospective cohort study was conducted.Sirolimus was initiated at 1 mg/(m^(2)×day),and dose adjustments were made by a 2-week titration period to attain a trough blood concentration of 5-10 ng/mL.The disappearance of RAML in chil-dren after sirolimus treatment was observed,and Cox regression was used to screen the factors affecting tumor disappearance.Results One hundred and twenty-six patients who met the criteria were analyzed.After 3 months,6 months,12 months,and 24 months of follow-up,tumors disappeared in 18(14.3%),30(23.8%),39(31.0%),and 42(33.3%)children,respec-tively.Tumors disappeared in 50(39.7%)children by the last visit of each individual,and 30(60%)of them occurred within 6 months.The multivariate Cox regression analysis showed that patients with a smaller maximum tumor diameter at baseline had a higher tumor disappearance rate.Thirty-six(29%)patients had stomatitis during the entire treatment period,and no serious adversereactionswereobserved.Conclusions Sirolimus could promote the disappearance of TSC-related RAML.The disappearance rate was correlated with the maximum diameter at baseline,and the smaller the tumor was,the higher the disappearance rate.It is well tolerated in the treatment of RAML associated with TSC.