PI3K inhibition in breast cancer: Identifying and overcoming different flavors of resistance

A Multiplex Assay for Fast PIK3CA Hotspot Mutation Characterization in a Single Specimen by 3-Color Digital PCR Analysis

BACKGROUND

Activating mutations in the phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) gene have been detected often in solid tumors. Targeted therapy for mutant PIK3CA is now available in the clinic, making molecular diagnostics pivotal. Our aim was to design a multiplex digital PCR (dPCR) assay to evaluate the 4 most common PIK3CA hotspot mutations simultaneously to characterize and quantify these in liquid biopsies.

METHODS

A multiplex assay was developed to detect exon 9 p.E542K and p.E545K mutations, and exon 20 p.H1047L and p.H1047R mutations using the Stilla 3-color dPCR Naica system. The assay was evaluated on stock and pre-amplified DNA from cell lines with the above mutations as single and pooled samples, and on cell-free DNA (cfDNA) from healthy blood donors (HBDs) and breast cancer patients, to determine detection thresholds and diagnostic accuracy.

RESULTS

The assay distinguished all 4 PIK3CA mutations in (cf)DNA, and also when dual mutations were present. Detection thresholds of stock and pre-amplified cfDNA samples were 0.11 and 0.40 copies/uL (cp/uL) for mutant copies concentration, and 0.003% and 0.68% for variant allele frequencies (VAFs), respectively. The assay confirmed the PIK3CA (mutation) status as defined by targeted next-generation sequencing (NGS) in 82 out of 96 patients that were mutant for PIK3CA, and in 11 out of 12 patients with wild-type PIK3CA.

CONCLUSIONS

Our designed multiplex dPCR assay detected PIK3CA mutations with high accuracy in stock and pre-amplified cfDNA. Furthermore, it is affordable and demands less cfDNA input when compared to available uniplex dPCR assays and NGS analyses.

Thiazolation of phenylthiosemicarbazone to access new thiazoles: anticancer activity and molecular docking

Aim: Novel thiazole hybrids were synthesized via thiazolation of 4-phenylthiosemicarbazone (4). Materials & methods: The anticancer activity against the NCI 60 cancer cell line panel. Results: Methyl 2-(2-((1-(naphthalen-2-yl)ethylidene)hydrazineylidene)-4-oxo-3-phenylthiazolidin-5-ylidene)acetate (6a) showed significant anticancer activity at 10 μM with a mean growth inhibition (GI) of 51.18%. It showed the highest cytotoxic activity against the ovarian cancer OVCAR-4 with an IC50 of 1.569 ± 0.06 μM. Compound 6a inhibited PI3Kα with IC50 = 0.225 ± 0.01 μM. Moreover, compound 6a revealed a decrease of Akt and mTOR phosphorylation in OVCAR-4 cells. In addition, antibacterial activity showed that compounds 11 and 12 were the most active against Staphylococcus aureus. Conclusion: Compound 6a is a promising molecule that could be a lead candidate for further studies.

MTCH2 stimulates cellular proliferation and cycles via PI3K/Akt pathway in breast cancer

The MTCH2 protein is located on the mitochondrial outer membrane and regulates mitochondria-related cell death. This study set out to investigate the role of MTCH2 in the underlying pathophysiological mechanisms of breast cancer (BC). MTCH2 expression levels in BC were analyzed using bioinformatics prior to verification by cell lines in vitro. Experiments of over-expression and siRNA-mediated knockdown of MTCH2 were conducted to assess its biological functions, including its effects on cellular proliferation and cycle progression. Xenografts were utilised for in vivo study and signaling pathway alterations were examined to identify the mechanisms driven by MTCH2 in BC proliferation and cell-cycle regulation. MTCH2 was up-regulated in BC and correlated with patients' overall survival. Over-expression of MTCH2 promoted cellular proliferation and cycle progression, while silencing MTCH2 had the opposite effect. Xenograft experiments were utilised to confirm the in vitro cellular findings and it was identified that the PI3K/Akt signaling pathway was activated by MTCH2 over-expression and suppressed by its silencing. Moreover, the activation of IGF-1R rescued cellular growth and cycle arrest induced by MTCH2-silencing. Overall, this study reveals that expression of MTCH2 in BC is upregulated and potentiates cellular proliferation and cycle progression via the PI3K/Akt pathway.

Cell-permeable PI3 kinase competitive peptide inhibits KIT mutant mediated tumorigenesis of gastrointestinal stromal tumor (GIST)

BACKGROUND

Mutations in the receptor tyrosine kinase KIT are the main cause of gastrointestinal stromal tumor (GIST), and the KIT mutants mediated PI3 kinase activation plays a key role in the tumorigenesis of GIST. In this study, we aimed to block PI3 kinase activation by cell-permeable peptide and investigate its possible application in the treatment of GIST.

METHODS AND RESULTS

We designed cell-permeable peptides based on the binding domain of PI3 kinase subunit p85 to KIT or PI3 kinase subunit p110, respectively, in order to compete for the binding between p85 and KIT or p110 and therefore inhibit the activation of PI3 kinases mediated by KIT. The results showed that the peptide can penetrate the cells, and inhibit the activation of PI3 kinases, leading to reduced cell survival and cell proliferation mediated by KIT mutants in vitro. Treatment of mice carrying germline KIT/V558A mutation, which can develop GIST, with the peptide that can compete for the binding between p85 and p110, led to reduced tumorigenesis of GIST. The peptide can further enhance the inhibition of the tumor growth by imatinib which is used as the first line targeted therapy of GIST.

CONCLUSIONS

Our results showed that cell-permeable PI3 kinase competitive peptide can inhibit KIT-mediated PI3 kinase activation and tumorigenesis of GIST, providing a rationale to further test the peptide in the treatment of GIST and even other tumors with over-activation of PI3 kinases.

Predictive, preventive, and personalized medicine in breast cancer: targeting the PI3K pathway

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.

Is Alpelisib Plus Fulvestrant Cost-Effective for Treating PIK3CA-Mutation, HR+/HER2- Advanced Breast Cancer in the USA?

BACKGROUND AND OBJECTIVE

There is a considerable survival benefit of alpelisib in patients with PIK3CA-mutated, hormone receptor-positive and human epidermal growth factor receptor 2-negative advanced breast cancer (HR+/HER2- ABC), yet the financial burden may limit its use. Therefore, this study evaluated the cost-effectiveness of alpelisib plus fulvestrant in patients with PIK3CA-mutated, HR+/HER2- ABC in the USA.

METHODS

A Markov model was constructed to simulate the progression of PIK3CA-mutated, HR+/HER2- ABC. Efficacy and safety data were derived from the SOLAR-1 trial. A parametric survival model was used to explore the long-term effect. From a US payer perspective, only direct medical costs were considered. The cost data were estimated based on local pricing and relevant literature. The health outcomes were expressed in quality-adjusted life years (QALYs). Model stability was assessed using one-way sensitivity analysis and probability sensitivity analysis. Subgroup analyses were performed to explore cost-effectiveness outcomes for patients with different clinical characteristics.

RESULTS

The QALY increased by 0.28 with alpelisib plus fulvestrant with an additional cost of $94,345.87 compared with placebo plus fulvestrant, leading to an incremental cost-effectiveness ratio (ICER) of $340,153.30/QALY gained. Sensitivity analyses suggested that the model is most sensitive to the price of alpelisib. At a willingness-to-pay (WTP) threshold of $150,000/QALY, alpelisib plus fulvestrant was cost effective when the cost of alpelisib was less than $71 per 300 mg (36.5 % of the original price), whereas this cost would be less than $168 per 300 mg (86.5 % of the original price) at a WTP threshold of $300,000/QALY. In addition, alpelisib + fulvestrant was not cost effective in all subgroups compared with placebo + fulvestrant at the WTP threshold of $150,000/QALY. In contrast, at the WTP threshold of $300,000/QALY, alpelisib + fulvestrant was cost effective in nearly all subgroups except for endocrine-sensitive patients.

CONCLUSION

At current drug prices, alpelisib plus fulvestrant is not cost effective for patients with PIK3CA-mutated, HR+/HER2- ABC from a US payer perspective. Given the considerable progression-free survival (PFS) and overall survival (OS) benefits observed with alpelisib in this setting, further discussion and negotiation of the price of alpelisib are warranted to provide more favorable economic outcomes and thereby increase the value of the alpelisib plus fulvestrant regimen in patients.

Discordance of PIK3CA mutational status between primary and metastatic breast cancer: a systematic review and meta-analysis

INTRODUCTION

In light of the clinically meaningful results of the PI3K inhibitors in PIK3CA-mutated metastatic breast cancer (BC) patients, the reliable identification of PIK3CA mutations is of outmost importance. However, lack of evidence on the optimal site and timing of assessment, presence of temporal heterogeneity and analytical factors pose several challenges in clinical routine. We aimed to study the discordance rates of PIK3CA mutational status between primary and matched metastatic tumors.

METHODS

A systematic literature search was performed in three different databases (Embase, Pubmed, Web of Science) and-upon screening-a total of 25 studies reporting PIK3CA mutational status both on primary breast tumors and their matched metastases were included in this meta-analysis. The random-effects model was used for pooled analyses of discordance of PIK3CA mutational status.

RESULTS

The overall discordance rate of PIK3CA mutational status was 9.8% (95% CI, 7.0-13.0; n = 1425) and did not significantly differ within BC subtypes or metastatic sites. The change was bi-directional, more commonly observed from PIK3CA mutated to wild-type status (14.9%, 95% CI 11.8-18.2; n tumor pairs = 453) rather than the opposite direction (8.9%, 95% CI 6.1-12.1; n tumor pairs = 943).

CONCLUSIONS

Our results indicate the need of obtaining metastatic biopsies for PIK3CA-mutation analysis and the possibility of testing of the primary tumor, in case a re-biopsy deemed non-feasible.

Combination of Ribociclib with BET-Bromodomain and PI3K/mTOR Inhibitors for Medulloblastoma Treatment In Vitro and In Vivo

Despite improvement in the treatment of medulloblastoma over the last years, numerous patients with MYC- and MYCN-driven tumors still fail current therapies. Medulloblastomas have an intact retinoblastoma protein RB, suggesting that CDK4/6 inhibition might represent a therapeutic strategy for which drug combination remains understudied. We conducted high-throughput drug combination screens in a Group3 (G3) medulloblastoma line using the CDK4/6 inhibitor (CDK4/6i) ribociclib at IC20, referred to as an anchor, and 87 oncology drugs approved by FDA or in clinical trials. Bromodomain and extra terminal (BET) and PI3K/mTOR inhibitors potentiated ribociclib inhibition of proliferation in an established cell line and freshly dissociated tumor cells from intracranial xenografts of G3 and Sonic hedgehog (SHH) medulloblastomas in vitro. A reverse combination screen using the BET inhibitor JQ1 as anchor, revealed CDK4/6i as the most potentiating drugs. In vivo, ribociclib showed single-agent activity in medulloblastoma models whereas JQ1 failed to show efficacy due to high clearance and insufficient free brain concentration. Despite in vitro synergy, combination of ribociclib with the PI3K/mTOR inhibitor paxalisib did not significantly improve the survival of G3 and SHH medulloblastoma-bearing mice compared with ribociclib alone. Molecular analysis of ribociclib and paxalisib-treated tumors revealed that E2F targets and PI3K/AKT/MTORC1 signaling genes were depleted, as expected. Importantly, in one untreated G3MB model HD-MB03, the PI3K/AKT/MTORC1 gene set was enriched in vitro compared with in vivo suggesting that the pathway displayed increased activity in vitro. Our data illustrate the difficulty in translating in vitro findings in vivo. See related article in Mol Cancer Ther (2022) 21(8):1306-1317.

Giant Paratesticular Liposarcoma: Molecular Characterization and Management Principles with a Review of the Literature

Paratesticular liposarcomas are extremely rare malignant tumors originating from fat tissues, with an often-challenging diagnosis. We present here the case of a 76-year-old man with a giant paratesticular liposarcoma, initially misdiagnosed as a scrotal hernia. After two years, the progressively enlarging mass underwent surgical resection, and a diagnosis of well-differentiated liposarcoma (lipoma-like subtype) was made. Post-operative treatments were not indicated, and the patient remains relapse free. Next generation sequencing performed on the neoplastic tissue showed co-amplification of MDM2 and CDK4. These alterations are molecular hallmarks of well-differentiated liposarcomas and corroborate the histological diagnosis. Clinical and molecular features of the presented case are in line with the majority of previously published experiences. In conclusion, the presence of a liposarcoma should be taken into account during the diagnostic workup of scrotal masses, in order to minimize the rate of misdiagnosis and improper management. Molecular analysis may support histological characterization of these rare entities and potentially disclose novel therapeutic targets.

Syringin exerts anti-breast cancer effects through PI3K-AKT and EGFR-RAS-RAF pathways

Background

Breast cancer (BC) is one of the most common malignant tumors with the highest mortality in the world. Modern pharmacological studies have shown that Syringin has an inhibitory effect on many tumors, but its anti-BC efficacy and mechanism are still unclear.

Methods

First, Syringin was isolated from Acanthopanax senticosus (Rupr. & Maxim.) Harms (ASH) by systematic solvent extraction and silica gel chromatography column. The plant name is composed of genus epithet, species additive words and the persons’ name who give its name. Then, the hub targets of Syringin against BC were revealed by bioinformatics. To provide a more experimental basis for later research, the hub genes which could be candidate biomarkers of BC and a ceRNA network related to them were obtained. And the potential mechanism of Syringin against BC was proved in vitro experiments.

Results

Syringin was obtained by liquid chromatography-mass spectrometry (LC–MS), nuclear magnetic resonance (NMR), and high-performance liquid chromatography (HPLC). Bioinformatics results showed that MAP2K1, PIK3CA, HRAS, EGFR, Caspase3, and PTGS2 were the hub targets of Syringin against BC. And PIK3CA and HRAS were related to the survival and prognosis of BC patients, the PIK3CA-hsa-mir-139-5p-LINC01278 and PIK3CA-hsa-mir-375 pathways might be closely related to the mechanism of Syringin against BC. In vitro experiments confirmed that Syringin inhibited the proliferation and migration and promoted apoptosis of BC cells through the above hub targets.

Conclusions

Syringin against BC via PI3K-AKT-PTGS2 and EGFR-RAS-RAF-MEK-ERK pathways, and PIK3CA and HRAS are hub genes for adjuvant treatment of BC.

Graphical Abstract

Exploring new pathways in endocrine-resistant breast cancer

The most common breast cancer (BC) subtypes are hormone-dependent, being either estrogen receptor-positive (ER⁺), progesterone receptor-positive (PR⁺), or both, and altogether comprise the luminal subtype. The mainstay of treatment for luminal BC is endocrine therapy (ET), which includes several agents that act either directly targeting ER action or suppressing estrogen production. Over the years, ET has proven efficacy in reducing mortality and improving clinical outcomes in metastatic and nonmetastatic BC. However, the development of ET resistance promotes cancer survival and progression and hinders the use of endocrine agents. Several mechanisms implicated in endocrine resistance have now been extensively studied. Based on the current clinical and pre-clinical data, the present article briefly reviews the well-established pathways of ET resistance and continues by focusing on the three most recently uncovered pathways, which may mediate resistance to ET, namely receptor activator of nuclear factor kappa B ligand (RANKL)/receptor activator of nuclear factor kappa B (RANK), nuclear factor kappa B (NFκB), and Notch. It additionally overviews the evidence underlying the approval of combined therapies to overcome ET resistance in BC, while highlighting the relevance of future studies focusing on putative mediators of ET resistance to uncover new therapeutic options for the disease.

Design, synthesis and activity study of a novel PI3K degradation by hijacking VHL E3 ubiquitin ligase

PI3K kinase plays an important role in regulating key processes in cells, such as cell growth, metabolism, proliferation, and apoptosis. The overexpression of PI3K kinase exists in many cancers. The proteolytic target chimera (PROTAC) technology is a new technology that uses the ubiquitin-proteasome system to degrade a given target protein. It has been described that CRBN-based PROTAC targets the degradation of PI3K kinase. However, PROTAC based on VHL has not been reported yet. Here, we connected the previously obtained highly active PI3K inhibitor to the VHL ligand through different small molecules, and obtained a series of PROTAC molecules targeting PI3K kinase. Obtain the most active compound through screening. It provides evidence for the feasibility of PROTAC technology to recruit VHL E3 ligase in PI3K kinase.

Mechanistic Translation of Melanoma Genetic Landscape in Enriched Pathways and Oncogenic Protein-Protein Interactions

BACKGROUND/AIM

Malignant melanoma is a skin cancer originating from the oncogenic transformation of melanocytes located in the epidermal layers. Usually, the patient's prognosis depends on timing of disease detection and molecular and genetic profiling, which may all significantly influence mortality rates. Genetic analyses often detect somatic BRAF, NRAS and cKIT mutations, germline substitutions in CDKN2A, and alterations of the PI3K-AKT-PTEN pathway. A peculiar molecular future of melanoma is its high immunogenicity, making this tumor targetable by programmed cell death protein 1-specific antibodies.

MATERIALS AND METHODS

Ten formalin-fixed paraffin embedded samples derived from melanoma patients were subjected to next-generation sequencing (NGS) analysis using the FDA-approved FoundationOne CDx™ test. The molecular features of each case were then analyzed employing several in silico prediction tools.

RESULTS

We analyzed the mutational landscape of patients with metastatic or relapsed cutaneous melanoma to define enriched pathways and protein-protein interactions. The analysis showed that both known genetic alterations and variants of unknown significance rely on redundant signaling converging on similar gene ontology biological processes. Complex informatics analyses of NGS-based genetic results identified pivotal signaling pathways that could provide additional targets for cancer treatment.

CONCLUSION

Our data suggest an additional role for NGS in melanoma, as analysis of comprehensive genetic findings using innovative informatic tools may lengthen the list of druggable molecular targets that impact patient outcome.

Everything Comes with a Price: The Toxicity Profile of DNA-Damage Response Targeting Agents

Simple Summary

DNA damage induces genome instability, which may elicit cancer development. Defects in the DNA repair machinery further enhance cancer predisposition, but can also be exploited as a therapeutic target. Indeed, targeted agents against specific components of DNA repair, such as PARP inhibitors, are employed in various tumor types, while others, such as ATR, CHK1 or WEE1 inhibitors, are in clinical development. Even though these molecules have proven to be effective in different settings, they display several on- and off-target toxicities, shared by the whole pharmacological class or are drug specific. Among these effects, hematological and gastrointestinal toxicities are the most common, while others are less frequent but potentially life-threatening (e.g., myelodysplastic syndromes). Particular caution is needed in the case of combinatorial therapeutic approaches, which are currently being developed in clinical trials. In any case, it is necessary to recognize and properly manage adverse events of these drugs. This review provides a comprehensive overview on the safety profile of DDR-targeting agents, including indications for their management in clinical practice.

Abstract

Targeting the inherent vulnerability of cancer cells with an impaired DNA Damage Repair (DDR) machinery, Poly-ADP-Ribose-Polymerase (PARP) inhibitors have yielded significant results in several tumor types, eventually entering clinical practice for the treatment of ovarian, breast, pancreatic and prostate cancer. More recently, inhibitors of other key components of DNA repair, such as ATR, CHK1 and WEE1, have been developed and are currently under investigation in clinical trials. The inhibition of DDR inevitably induces on-target and off-target adverse events. Hematological and gastrointestinal toxicities as well as fatigue are common with all DDR-targeting agents, while other adverse events are drug specific, such as hypertension with niraparib and transaminase elevation with rucaparib. Cases of pneumonitis and secondary hematological malignancies have been reported with PARP inhibitors and, despite being overly rare, they deserve particular attention due to their severity. Safety also represents a crucial issue for the development of combination regimens incorporating DDR-targeting agents with other treatments, such as chemotherapy, anti-angiogenics or immunotherapy. As such, overlapping and cumulative toxicities should be considered, especially when more than two classes of drugs are combined. Here, we review the safety profile of DDR-targeting agents when used as single agents or in combination and we provide principles of toxicity management.

PIK3CA-mutations in breast cancer

PURPOSE

Phosphatidylinositide-3-kinase (PI3K) regulates proliferation and apoptosis; somatic PIK3CA-mutations may activate these processes. Aim of this study was to determine the prevalence of PIK3CA-mutations in a cohort of early stage breast cancer patients and the association to the course of disease.

PATIENTS AND METHODS

From an unselected cohort of 1270 breast cancer patients (PiA, Prognostic Assessment in routine application, NCT01592825) 1123 tumours were tested for the three PIK3CA hotspot-mutations H1047R, E545K, and E542K by qPCR. Primary objectives were the prevalence of somatic PIK3CA-mutations and their association to tumour characteristics. Secondary objective was the association of PIK3CA-mutations to recurrence-free interval (RFI) and overall survival.

RESULTS

PIK3CA-mutation rate was 26.7% (300 of 1123). PIK3CA-mutations were significantly more frequent in steroid hormone-receptor (SHR)-positive HER2-negative (31.4%), and G1 and G2 tumours (32.8%). Overall, we did not observe a significant association of PIK3CA-mutations to RFI. In SHR-positive BCs with PIK3CA-mutations, a strong trend for impaired  RFI was observed (adjusted HR 1.64, 95% CI 0.958-2.807), whilst in SHR-negative BCs PIK3CA-mutations were insignificantly associated with improved RFI (adjusted HR 0.49; 95% CI 0.152-1.597). Of note, we observed a significantly detrimental prognostic impact of PIK3CA-mutations on RFI in SHR-positive, HER2-negative BCs if only aromatase inhibitors were administered as adjuvant therapy (adjusted HR 4.44, 95% CI 1.385-13.920), whilst no impact was observed in tamoxifen treated patients.

CONCLUSION

This cohort study speficies the overall mutation rate of PIK3CA in early breast cancer. The impact of PIK3CA-mutations on RFI and OS was heterogeneous. Our results suggest that estrogen deprivation failes to be active in case of PIK3CA-mutation.

A New Kid on the Block: Sacituzumab Govitecan for the Treatment of Breast Cancer and Other Solid Tumors

Human trophoblast cell-surface antigen-2 (Trop-2) is a membrane glycoprotein involved in cell proliferation and motility, frequently overexpressed in epithelial tumors. Thus, it represents an attractive target for anticancer therapies. Sacituzumab govitecan (SG) is a third-generation antibody-drug conjugate, consisting of an anti-Trop-2 monoclonal antibody (hRS7), a hydrolyzable linker, and a cytotoxin (SN38), which inhibits topoisomerase 1. Specific pharmacological features, such as the high antibody to payload ratio, the ultra-toxic nature of SN38, and the capacity to kill surrounding tumor cells (the bystander effect), make SG a very promising drug for cancer treatment. Indeed, unprecedented results have been observed with SG in patients with heavily pretreated advanced triple-negative breast cancer and urothelial carcinomas, and the drug has already received approval for these indications. These results are coupled with a manageable toxicity profile, with neutropenia and diarrhea as the most frequent adverse events, mainly of grades 1-2. While several trials are exploring SG activity in different tumor types and settings, potential biomarkers of response are under investigation. Among these, Trop-2 overexpression and the presence of BRCA1/2 mutations seem to be the most promising. We review the available literature concerning SG, with a focus on its toxicity spectrum and possible biomarkers of its response.

Tanshinone IIa Induces Autophagy and Apoptosis via PI3K/Akt/mTOR Axis in Acute Promyelocytic Leukemia NB4 Cells

Tanshinone IIa (TanIIa), an ingredient of Radix Salviae Miltiorrhizae, has an anticancer effect on various solid tumors with high efficiency and low toxicity. Nonetheless, the underlying role of TanIIa in acute promyelocytic leukemia (APL) remains unclear. Here, we revealed that TanIIa drastically inhibited NB4 cell viability with an IC50 value of 31.25 μmol/L. Using flow cytometry apoptosis assay, we identified that TanIIa dose-dependently exacerbated NB4 cell apoptosis. Mechanistically, TanIIa upregulated apoptotic factor levels, namely, cleaved-caspase 9, cleaved-caspase 3, and cleaved-PARP-1. Moreover, we noticed that TanIIa dose-dependently suppressed the PI3K/Akt/mTOR axis. This axis not only functions as an essential antiapoptotic modulator but also serves as a suppressant regulator of autophagy. Correspondingly, we detected the levels of autophagic marker, namely, LC3B, which were increased after the TanIIa treatment. Furthermore, the autophagy inhibitor Baf-A1 could effectively reverse the TanIIa-induced apoptosis, manifesting that TanIIa eliminated NB4 cells in an autophagy-dependent manner. In conclusion, tanshinone IIa exerts anti-APL effects through triggering autophagy and apoptosis in NB4 cells.

PIK3CA mutation in a case of CTNNB1 mutant sinonasal glomangiopericytoma

Glomangiopericytomas are rare, primary sinonasal tumors. The existing literature is mostly limited to reports describing the clinicopathologic characteristics of these tumors. Comprehensive genetic characterization of glomangiopericytomas remain lacking. Whole exome sequencing of a case of glomangiopericytoma was performed under an institutional review board approved protocol. A 69 year-old female underwent surgical resection of a glomangiopericytoma. Whole exome sequencing revealed somatic mutations in CTNNB1 and PIK3CA, the former previously associated with this pathology but the latter not described. Concurrent dysregulation of Wnt/beta-catenin and PI3K/AKT/mTOR signaling, secondary to mutations in these two oncogenes may be amenable to targeted treatment with existing clinically approved drugs. Genomic characterization of glomangiopericytomas remains lacking. This study reports novel co-existence of PIK3CA and CTNNB1 mutations in a case of glomangiopericytoma that may offer insight into the pathogenesis and potential for targeted medical therapies of this rare tumor.