Targeting PI3K signalling in cancer: opportunities, challenges and limitations

The small molecule kobusone can stimulate islet β-cell replication in vivo

OBJECTIVE

To investigate the ability of kobusone to reduce high glucose levels and promote β-cell proliferation.

METHODS

Four-week-old female db/db mice were assigned to the kobusone (25 mg/kg body weight, intraperitoneally twice a day) or control group (same volume of PBS). Glucose levels and body weight were measured twice a week. After 6 weeks, intraperitoneal glucose tolerance tests and immunohistochemical studies were performed, and insulin levels were determined. The expression of mRNAs involved in cell proliferation, such as PI3K, Akt, cyclin D3 and p57^Kip2, was measured by quantitative reverse transcription polymerase chain reaction (RT-qPCR).

RESULTS

Kobusone reduced blood glucose levels after 3 weeks and more strongly increased serum insulin levels than the vehicle. Immunohistochemistry illustrated that kobusone increased 5-bromo-2'-deoxyuridine incorporation into islet β-cells, suggesting that it can stimulate islet β-cell replication in vivo. RT-qPCR indicated that kobusone upregulated the mRNA expression of PI3K, Akt, and cyclin D3 and downregulated that of p57^Kip2.

CONCLUSION

Our findings suggest that kobusone is a potent pancreatic islet β-cell inducer that has the potential to be developed as an anti-diabetic agent.

Targeting the PI3K/AKT/mTOR Pathway in Hormone-Positive Breast Cancer

Approximately 70% of invasive breast cancers have some degree of dependence on the estrogen hormone for cell proliferation and growth. These tumors have estrogen and/or progesterone receptors (ER/PR+), generally referred to as hormone receptor positive (HR+) tumors, as indicated by the presence of positive staining and varying intensity levels of estrogen and/or progesterone receptors on immunohistochemistry. Therapies that inhibit ER signaling pathways, such as aromatase inhibitors (letrozole, anastrozole, exemestane), selective ER modulators (tamoxifen), and ER down-regulators (fulvestrant), are the mainstays of treatment for hormone-receptor-positive breast cancers. However, de novo or acquired resistance to ER targeted therapies is present in many tumors, leading to disease progression. The PI3K/AKT/mTOR pathway is implicated in sustaining endocrine resistance and has become the target of many new drugs for ER+ breast cancer. This article reviews the function of the phosphoinositide 3-kinase (PI3K)/AKT/mTOR pathway and the various classes of PI3K pathway inhibitors that have been developed to disrupt this pathway signaling for the treatment of hormone-receptor-positive breast cancer.

Synthesis and biological evaluation of novel purinyl quinazolinone derivatives as PI3Kδ-specific inhibitors for the treatment of hematologic malignancies

Phosphatidylinositol 3-kinases (PI3Ks) mediate intracellular signal transduction. Aberrant PI3K signaling is associated with oncogenesis and disease progression in solid tumors and hematologic malignancies. Idelalisib (1), a first-in-class PI3Kδ inhibitor for the treatment of hematologic malignancies, was developed, but its sales were limited by black box warnings due to unexpected adverse effects. Therefore, to overcome these adverse events, various quinazolinone derivatives were synthesized and evaluated in vitro based on their inhibitory activity against the PI3K enzyme and the viability of cell lines such as MOLT and SUDHL. Among them, 6f (IC₅₀ = 0.39 nM) and 6m (IC₅₀ = 0.09 nM) showed excellent enzyme activity, and 6m displayed an approximately four-fold higher selectivity for PI3Kγ/δ compared with Idelalisib (1). Furthermore, in vivo PK experiments with 6f and 6m revealed that 6f (AUC_last = 81.04 h*ng/mL, C_max = 18.34 ng/mL, T_max = 0.5 h, t_1/2 = 10.2 h in 1 mpk dose) had improved PK compared with 1. Finally, further experiments will be conducted with 6f selected as a candidate, and the potential for it to be developed as a treatment with good efficacy for hematologic malignancies will be determined.

Tacrolimus inhibits insulin release and promotes apoptosis of Min6 cells through the inhibition of the PI3K/Akt/mTOR pathway

As a calcineurin inhibitor, tacrolimus is commonly used as a first‑line immunosuppressant in organ transplant recipients. Post‑transplantation diabetes mellitus (PTDM) is a common complication following kidney transplantation and is associated with immunosuppressant drugs, such as tacrolimus. PTDM caused by tacrolimus may be related to its influence on insulin secretion and insulin resistance. However, the specific mechanism has not been fully elucidated. The aim of the present study was to investigate whether the PI3K/Akt/mTOR signaling pathway served an important role in the pathogenesis of PTDM induced by tacrolimus. In the present study, the Cell Counting Kit‑8 assay was used to measure the effect of tacrolimus on the viability of Min6 mouse insulinoma cells. The effects of tacrolimus on the insulin secretion and the activity of caspase‑3 of Min6 cells stimulated by glucose exposure were measured by ELISA. Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were measured using WST‑8 and thiobarbituric acid assays, respectively. The effects of tacrolimus on the mRNA expression levels of PI3K, Akt and mTOR were detected by reverse transcription‑quantitative PCR (RT‑qPCR), whereas the protein expression levels of PI3K, Akt, mTOR, phosphorylated (p)‑AKT and p‑mTOR in Min6 cells were assessed using western blotting. The present data indicated that, compared with the control group, 5, 25 and 50 ng/ml tacrolimus treatment could inhibit the insulin secretion of Min6 cells stimulated by glucose solution, and 50 ng/ml tacrolimus could notably decrease the stimulation index (P<0.05). Moreover, 50 ng/ml tacrolimus markedly increased the activity of caspase‑3 by 175.1% (P<0.05), it also decreased the SOD activity (P<0.01) and increased MDA levels (P<0.05). The RT‑qPCR results demonstrated that the mRNA expression levels of PI3K, Akt and mTOR were downregulated by 25 and 50 ng/ml tacrolimus (P<0.01). Furthermore, the western blotting results suggested that tacrolimus had no significant effects on the expression levels of total PI3K, Akt and mTOR proteins (P>0.05), but 25 and 50 ng/ml tacrolimus could significantly inhibit the expression levels of p‑Akt and p‑mTOR (P<0.01). In conclusion, tacrolimus decreased the activity and insulin secretion of pancreatic β cells and induced the apoptosis of islet β cells by inhibiting the mRNA expression levels of PI3K, Akt and mTOR and reducing the phosphorylation of Akt and mTOR proteins in the PI3K/Akt/mTOR signaling pathway, which may ultimately lead to the occurrence of diabetes mellitus, and may be considered as one of the specific mechanisms of PTDM caused by tacrolimus.

miRNome and Functional Network Analysis of PGRMC1 Regulated miRNA Target Genes Identify Pathways and Biological Functions Associated With Triple Negative Breast Cancer

Background

Increased expression of the progesterone receptor membrane component 1, a heme and progesterone binding protein, is frequently found in triple negative breast cancer tissue. The basis for the expression of PGRMC1 and its regulation on cellular signaling mechanisms remain largely unknown. Therefore, we aim to study microRNAs that target selective genes and mechanisms that are regulated by PGRMC1 in TNBCs.

Methods

To identify altered miRNAs, whole human miRNome profiling was performed following AG-205 treatment and PGRMC1 silencing. Network analysis identified miRNA target genes while KEGG, REACTOME and Gene ontology were used to explore altered signaling pathways, biological processes, and molecular functions.

Results

KEGG term pathway analysis revealed that upregulated miRNAs target specific genes that are involved in signaling pathways that play a major role in carcinogenesis. While multiple downregulated miRNAs are known oncogenes and have been previously demonstrated to be overexpressed in a variety of cancers. Overlapping miRNA target genes associated with KEGG term pathways were identified and overexpression/amplification of these genes was observed in invasive breast carcinoma tissue from TCGA. Further, the top two genes (CCND1 and YWHAZ) which are highly genetically altered are also associated with poorer overall survival.

Conclusions

Thus, our data demonstrates that therapeutic targeting of PGRMC1 in aggressive breast cancers leads to the activation of miRNAs that target overexpressed genes and deactivation of miRNAs that have oncogenic potential.

Phase I Dose-Escalation Study of the Dual PI3K-mTORC1/2 Inhibitor Gedatolisib in Combination with Paclitaxel and Carboplatin in Patients with Advanced Solid Tumors

PURPOSE

This phase I study evaluated safety, tolerability, pharmacokinetics, and preliminary activity of the PI3K/mTORC1/2 dual inhibitor gedatolisib combined with carboplatin and paclitaxel.

PATIENTS AND METHODS

Patients with advanced solid tumors treated with ≤ 2 prior chemotherapies received intravenous gedatolisib on days 1, 8, 15, and 22 (95, 110, or 130 mg according to dose level); carboplatin (AUC5) on day 8 (day 1 following protocol amendment); and paclitaxel at 80 mg/m² on days 8, 15, and 22 (1, 8, and 15 after amendment), every 28 days. Patients without progressive disease after cycle 6 received maintenance gedatolisib until progression.

RESULTS

Seventeen patients were enrolled [11 ovarian (10 clear cell ovarian cancer, CCOC), 4 endometrial, 2 lung cancers]. Median number of prior chemotherapies was 1 (range, 0-2). Median number of administered cycles was 6 (range, 2-16). Dose-limiting toxicities occurred in 4 patients: 2 (cycle 2 delay due to G2-G3 neutropenia) at 110 mg leading to a change in the treatment schedule, 2 at 130 mg (G2 mucositis causing failure to deliver ≥ 75% of gedatolisib at cycle 1). The recommended phase II dose is gedatolisib 110 mg on days 1, 8, 15, and 22 with carboplatin AUC5 on day 1 and paclitaxel 80 mg/m² on days 1, 8, and 15. The most frequent ≥G3 treatment-related adverse events were neutropenia (35%), anemia (18%), and mucositis (12%). The overall response rate was 65% (80% in CCOC). Pharmacokinetic parameters of gedatolisib were consistent with single-agent results.

CONCLUSIONS

Gedatolisib combined with carboplatin and paclitaxel is tolerable, and preliminary efficacy was observed especially in CCOC.

Molecular Pathways and Druggable Targets in Head and Neck Squamous Cell Carcinoma

Head and neck cancers are a heterogeneous group of neoplasms, affecting an ever increasing global population. Despite advances in diagnostic technology and surgical approaches to manage these conditions, survival rates have only marginally improved and this has occurred mainly in developed countries. Some improvements in survival, however, have been a result of new management and treatment approaches made possible because of our ever-increasing understanding of the molecular pathways triggered in head and neck oncogenesis, and the growing understanding of the abundant heterogeneity of this group of cancers. Some important pathways are common to other solid tumours, but their impact on reducing the burden of head and neck disease has been less than impressive. Other less known and little-explored pathways may hold the key to the development of potential druggable targets. The extensive work carried out over the last decade, mostly utilising next generation sequencing has opened up the development of many novel approaches to head and neck cancer treatment. This paper explores our current understanding of the molecular pathways of this group of tumours and outlines associated druggable targets which are deployed as therapeutic approaches in head and neck oncology with the ultimate aim of improving patient outcomes and controlling the personal and economic burden of head and neck cancer.

Colorectal Cancer: From Genetic Landscape to Targeted Therapy

Colorectal cancer (CRC) is the third most common cancer type and the second cause of death worldwide. The advancement in understanding molecular pathways involved in CRC has led to new classifications based on the molecular characteristics of each tumor and also improved CRC management through the integration of targeted therapy into clinical practice. In this review, we will present the main molecular pathways involved in CRC carcinogenesis, the molecular classifications. The anti-VEGF and anti-EGFR therapies currently used in CRC treatment and those under clinical investigation will also be outlined, as well as the mechanisms of primary and acquired resistance to anti-EGFR monoclonal antibodies (cetuximab and panitumumab). Targeted therapy has led to great improvement in the treatment of metastatic CRC. However, there has been variability in CRC treatment outcomes due to molecular heterogeneity in colorectal tumors, which underscores the need for identifying prognostic and predictive biomarkers for CRC-targeted drugs.

Triple-negative breast cancer: A run-through of features, classification and current therapies

Breast cancer is the most prevalent cancer in women worldwide. Triple-negative breast cancer (TNBC) is characterized by the lack of expression of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. It is the most aggressive subtype of breast cancer and accounts for 12-20% of all breast cancer cases. TNBC is associated with younger age of onset, greater metastatic potential, higher incidence of relapse, and lower overall survival rates. Based on molecular phenotype, TNBC has been classified into six subtypes (BL1, BL2, M, MES, LAR, and IM). TNBC treatment is challenging due to its heterogeneity, highly invasive nature, and relatively poor therapeutics response. Chemotherapy and radiotherapy are conventional strategies for the treatment of TNBC. Recent research in TNBC and mechanistic understanding of disease pathogenesis using cutting-edge technologies has led to the unfolding of new lines of therapies that have been incorporated into clinical practice. Poly (ADP-ribose) polymerase and immune checkpoint inhibitors have made their way to the current TNBC treatment paradigm. This review focuses on the classification, features, and treatment progress in TNBC. Histological subtypes connected to recurrence, molecular classification of TNBC, targeted therapy for early and advanced TNBC, and advances in non-coding RNA in therapy are the key highlights in this review.

Comprehensive genomic profiling of histologic subtypes of urethral carcinomas

BACKGROUND

Carcinoma of the urethra (UrthCa) is an uncommon Genitourinary (GU) malignancy that can progress to advanced metastatic disease.

METHODS

One hundred twenty-seven metastatic UrthCa underwent hybrid capture-based comprehensive genomic profiling to evaluate all classes of genomic alterations (GA). Tumor mutational burden was determined on up to 1.1 Mbp of sequenced DNA, and microsatellite instability was determined on 114 loci. PD-L1 expression was determined by IHC (Dako 22C3).

RESULTS

Forty-nine (39%) urothelial (UrthUC), 31 (24%) squamous (UrthSCC), 24 (19%) adenocarcinomas NOS (UrthAC), and 12 (9%) clear cell (UrthCC) were evaluated. UrthUC and UrthSCC are more common in men; UrthAC and UrthCC are more common in women. Ages were similar in all 4 groups. GA in PIK3CA were the most frequent potentially targetable GA; mTOR pathway GA in PTEN were also identified. GA in other potentially targetable genes were also identified including ERBB2 (6% in UrthUC, 3% in UrthSCC, and 12% in UrthAC), FGFR1-3 (3% in UrthSCC), BRAF (3% in UrthAC), PTCH1 (8% in UrthCC), and MET (8% in UrthCC). Possibly reflecting their higher GA/tumor status, potential for immunotherapy benefit associated with higher tumor mutational burden and PD-L1 staining levels were seen in UrthUC and UrthSCC compared to UrthAC and UrthCC. Microsatellite instability high status was absent throughout.

CONCLUSIONS

Comprehensive genomic profiling reveals GA that may be predictive of both targeted and immunotherapy benefit in patients with advanced UrthCa and that could potentially be used in future adjuvant, neoadjuvant, and metastatic disease trials.

A Reductionist Approach Using Primary and Metastatic Cell-Derived Extracellular Vesicles Reveals Hub Proteins Associated with Oral Cancer Prognosis

Oral squamous cell carcinoma (OSCC) has high mortality rates that are largely associated with lymph node metastasis. However, the molecular mechanisms that drive OSCC metastasis are unknown. Extracellular vesicles (EVs) are membrane-bound particles that play a role in intercellular communication and impact cancer development and progression. Thus, profiling EVs would be of great significance to decipher their role in OSCC metastasis. For that purpose, we used a reductionist approach to map the proteomic, miRNA, metabolomic, and lipidomic profiles of EVs derived from human primary tumor (SCC-9) cells and matched lymph node metastatic (LN1) cells. Distinct omics profiles were associated with the metastatic phenotype, including 670 proteins, 217 miRNAs, 26 metabolites, and 63 lipids differentially abundant between LN1 cell– and SCC-9 cell–derived EVs. A multi-omics integration identified 11 ‘hub proteins’ significantly decreased at the metastatic site compared with primary tumor–derived EVs. We confirmed the validity of these findings with analysis of data from multiple public databases and found that low abundance of seven ‘hub proteins’ in EVs from metastatic lymph nodes (ALDH7A1, CAD, CANT1, GOT1, MTHFD1, PYGB, and SARS) is correlated with reduced survival and tumor aggressiveness in patients with cancer. In summary, this multi-omics approach identified proteins transported by EVs that are associated with metastasis and which may potentially serve as prognostic markers in OSCC.

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Proteomic, miRNA, metabolomic, and lipidomic profiles were mapped in oral cancer EVs.

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The molecular profile of EVs was associated with the lymph node metastatic phenotype.

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A multi-omics integrative analysis revealed 11 highly connected ‘hub proteins.’

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‘Hub proteins’ from EVs are candidates as prognostic markers in oral cancer.

Clinicopathological and Genomic Profiles of Atypical Fibroxanthoma and Pleomorphic Dermal Sarcoma Identify Overlapping Signatures with a High Mutational Burden

Atypical fibroxanthoma (AFX) and pleomorphic dermal sarcoma (PDS) are rare tumors developing in chronically sun-exposed skin. Clinicopathological features are similar, but they differ in prognosis, while PDS has a more aggressive course with a higher risk for local recurrence and metastases. In current clinical practice, they are diagnosed by exclusion using immunohistochemistry. Thus, stringent diagnostic criteria and correct differentiation are critical in management and treatment for optimal outcomes. This retrospective single-center study collected clinicopathological data and tumor samples of 10 AFX and 18 PDS. Extracted genomic DNA from tumor specimens was analyzed by a next-generation sequencing (NGS) platform (FoundationOne-CDx™). Among 65 identified mutations, TP53 inactivating mutations were observed in all tumor specimens. In both AFX and PDS, the known pathogenic gene alterations in CDKN2A, TERT promoter, and NOTCH1 were frequently present, along with high mutational burden and stable Micro-Satellite Instability status. The mutational profiles differed only in ASXL1, which was only present in AFX. Further differences were identified in likely pathogenic and unknown gene alterations. Similarities in their genomic signatures could help to distinguish them from other malignancies, but they are not distinguishable between each other using the FoundationOne-CDx™ NGS panel. Therefore, histological criteria to determine diagnosis remain valid. For further insight, performing deep tumor profiling may be necessary.

TCP1 regulates PI3K/AKT/mTOR signaling pathway to promote proliferation of ovarian cancer cells

OBJECTIVE

TCP1 is one of the eight subunits of the TCP1 ring complex (TRiC) or the multi-protein mammalian cytosolic chaperone complex. TRiC participates in protein folding and regulates the expression of multiple signaling proteins and cytoskeletal components in cells. Although the clinical importance of its subunits has been clarified in various carcinomas, the function of TCP1 in ovarian cancer (OC) remains unclear. We aimed to identify the association between the expression of TCP1 and the development of epithelial OC (EOC) and patient prognosis, and explore the underlying mechanisms of TCP1 on the tumor progression of OC cells.

METHODS

TCP1 protein expression was tested in various ovarian tissues by immunohistochemistry, and the correlation between TCP1 expression and clinical physiologic or pathologic parameters of patients with EOC was analyzed. The relationship between TCP1 expression and the prognosis of patients with OC was investigated and analyzed using the Kaplan-Meier (KM) plotter online database. The expression level of TCP1 was then tested in different OC cell lines by Western blotting. Further, a model using OC cell line A2780 was constructed to study the functions of TCP1 in growth, migration, and invasion of human EOC cells. Finally, the possible regulating signaling pathways were discussed.

RESULTS

TCP1 protein expression in OC or borderline tissues was significantly higher than that in benign ovarian tumors and normal ovarian tissue. The upregulated expression of TCP1 in OC was positively associated with the differentiation grade and FIGO stage of tumors and predicted poor clinical outcomes. Compared with IOSE-80 cells, TCP1 protein was overexpressed in A2780 cells. TCP1 knockdown using shRNA lentivirus inhibited the viability of A2780 cells. Western blotting showed that the phosphatidylinositol-3 kinase (PI3K) signaling pathway was activated in the tumor invasion in EOC driven by TCP1.

CONCLUSION

Upregulated TCP1 is correlated with the poor prognosis of patients with OC. The mechanism of cancer progression promoted by TCP1 upregulation may be linked to the activation of the PI3K signaling pathway, and TCP1 may serve as a novel target for the treatment of OC.

Silencing UHRF1 Enhances Radiosensitivity of Esophageal Squamous Cell Carcinoma by Inhibiting the PI3K/Akt/mTOR Signaling Pathway

Purpose

Resistance to radiotherapy results in a high treatment failure rate for locally advanced esophageal squamous cell carcinoma (ESCC). Ubiquitin-like with plant homeodomain and ring-finger domains 1 (UHRF1), is associated with poor prognosis in ESCC. The present study aims to characterize the effect of UHRF1 silencing on the radiosensitivity of ESCC and its potential mechanism.

Methods

Both in vitro and in vivo experiments were conducted to observe the effects of UHRF1 silencing on the radiosensitivity of ESCC. The effects of UHRF1 silencing on the apoptosis of ESCC cells were assessed by flow cytometry. The expression of apoptosis-related factors (caspase-3 and Bcl-2), PI3K/Akt/mTOR signaling pathway-related factors (PTEN, p-Akt and Akt, p-mTOR and mTOR), and DNMT1 were measured via Western blot, and the status of PTEN methylation was detected by methylation-specific PCR. Immunohistochemistry was used to detect the expressions of PTEN, p-AKT, and p-mTOR in xenograft tumor tissues.

Results

In vitro and in vivo experiments showed that UHRF1 knock-down inhibited ESCC cell growth and enhanced their radiosensitivity. shUHRF1 combined with radiation significantly increased ESCC cell apoptosis. Meanwhile, it activated the expression of caspase-3 and inhibited the expression of Bcl-2. shUHRF1 inhibited the expression of DNMT1 and reduced the methylation of PTEN, and then upregulated the expression of PTEN to inhibit the PI3K/Akt/mTOR signaling pathway. On the contrary, the PI3K/Akt/mTOR signaling pathway can be activated by upregulation of UHRF1.

Conclusion

Our findings provide a theoretical basis for UHRF1 as a target to improve the radiosensitivity of ESCC.

Anticancer potential of novel α,β-unsaturated γ-lactam derivatives targeting the PI3K/AKT signaling pathway

Six recently synthesized alkyl (Z)-2-(2-oxopyrrolidin-3-ylidene)acetates were evaluated for their potential as cytotoxic and anticancer agents. All compounds were tested in the ERα positive MCF-7, triple negative MDA-MB-231, and Her2⁺ SKBR-3 breast cancer cell lines. The most lipophilic derivatives, bearing the 4-isopropylphenyl (2) or 4-tert-butylphenyl (3) group at the γ-lactam nitrogen, proved to be cytotoxic against all the cancer cell lines tested (IC₅₀ values ranging from 18 to 63 μM), exerting their greatest activity in SKBR-3 cells, with IC₅₀ values of 33 and 18 μM, respectively. Biological studies showed that the cytotoxic effects of 2 and 3 are accompanied by apoptotic death in breast cancer cells, and both compounds showed no significant toxicity on healthy cells (e.g., MCF-10A) and red blood cells. An in-depth mechanistic study based on molecular biology, immunoblotting analysis and in silico docking calculations suggested that α,β-unsaturated γ-lactam derivatives could interfere with the functioning of PI3K and PDK-1, two key enzymes in the PI3K/AKT signaling pathway, whose overactivation is related to the regulation of cell growth and survival in several malignancies.

A Novel Ruthenium-Fluvastatin Complex Downregulates SNCG Expression to Modulate Breast Carcinoma Cell Proliferation and Apoptosis via Activating the PI3K/Akt/mTOR/VEGF/MMP9 Pathway

Breast cancer is the most common cause of malignancy and cancer-related morbidity and death worldwide that requests effective and safe chemotherapy. Evaluation of metallodrug-based anticancer agents and statins as chemotherapeutics with fewer side effects is a largely unexplored research field. Synthesis and characterization of the ruthenium-fluvastatin complex were achieved using multiple spectroscopic techniques and thus further examined to evaluate its chemotherapeutic prospects in both MDA-MB-231 and MCF-7 cancer lines and eventually in vivo models of DMBA-induced mammary carcinogenesis in rodents. Our studies indicate that the metal and ligand chelation was materialized by the ligand's functional groups of carbonyl (=O) oxygen and hydroxyl (-OH), and the complex has been observed to be crystalline and able to chelate with CT-DNA. The complex was able to reduce cell proliferation and activate apoptotic events in breast carcinoma cell lines MCF-7 and MDA-MB-231. In addition, the complex was able to modify p53 expressions to interfere with apoptosis in the carcinoma of the breast, stimulated by the intrinsic apoptotic path assisted by Bcl2 and Bax in vivo, yet at the same point, controlling the PI3K/Akt/mTOR/VEGF pathway, as obtained from western blotting, correlates with the MMP9-regulated tumor mechanisms. Our research reveals that ruthenium-fluvastatin chemotherapy may disrupt, rescind, or interrupt breast carcinoma progression by modifying intrinsic apoptosis as well as the antiangiogenic cascade, thereby taking the role of a potential candidate in cancer therapy for the immediate future.

Somatic frameshift mutation in PIK3CA causes CLOVES syndrome by provoking PI3K/AKT/mTOR pathway

Background

CLOVES syndrome (OMIM# 612918) is a rare overgrowth disorder resulted from mosaic gain-of-function mutations in the PIK3CA gene. All the reported CLOVES-associated PIK3CA mutations are missense mutations affecting certain residues. We aim to investigate underlying mutation and its pathogenicity in a patient with CLOVES syndrome and to evaluate the inhibitory effects of the PI3K/AKT/mTOR pathway inhibitors.

Results

We performed whole-exome sequencing (WES) and Sanger sequencing to detect underlying somatic mutations in the skin lesion of the patient. Quantitative real-time PCR (qRT-PCR) was employed to evaluate the mRNA abundance of PIK3CA in the patient’s skin lesion. AKT phosphorylation level assessed by immunoblotting of lysates from transiently transfected cells was performed to evaluate the PIK3CA mutations and inhibitory effects of PI3K/AKT/mTOR pathway inhibitors. A somatic frameshift mutation c.3206_3207insG (p.X1069Trpfs*4) in PIK3CA was identified in the genomic DNA extracted from the vascular malformation sample of the patient. This mutation affects the canonical stop codon of PIK3CA (NM_006218.4) and is predicted to produce a prolonged protein with four additional residues. qRT-PCR demonstrated that the mRNA expression levels of the patient’s affected skin tissue were comparable compared to the normal control. In vitro studies revealed that p.X1069Trpfs*4 mutant exhibited increased AKT phosphorylation significantly to that of the wildtype, which could be inhibited by PI3K/AKT/mTOR pathway inhibitors.

Conclusions

We have identified the first frameshift mutation in PIK3CA that causes CLOVES syndrome, which was confirmed to overactive PI3K/AKT/mTOR pathway by transient transfection assays. We also provided more evidence of ARQ092 to be a potential therapeutic option for PROS in vitro.

Multiscale modeling of tumor growth and angiogenesis: Evaluation of tumor-targeted therapy

The dynamics of tumor growth and associated events cover multiple time and spatial scales, generally including extracellular, cellular and intracellular modifications. The main goal of this study is to model the biological and physical behavior of tumor evolution in presence of normal healthy tissue, considering a variety of events involved in the process. These include hyper and hypoactivation of signaling pathways during tumor growth, vessels' growth, intratumoral vascularization and competition of cancer cells with healthy host tissue. The work addresses two distinctive phases in tumor development-the avascular and vascular phases-and in each stage two cases are considered-with and without normal healthy cells. The tumor growth rate increases considerably as closed vessel loops (anastomoses) form around the tumor cells resulting from tumor induced vascularization. When taking into account the host tissue around the tumor, the results show that competition between normal cells and cancer cells leads to the formation of a hypoxic tumor core within a relatively short period of time. Moreover, a dense intratumoral vascular network is formed throughout the entire lesion as a sign of a high malignancy grade, which is consistent with reported experimental data for several types of solid carcinomas. In comparison with other mathematical models of tumor development, in this work we introduce a multiscale simulation that models the cellular interactions and cell behavior as a consequence of the activation of oncogenes and deactivation of gene signaling pathways within each cell. Simulating a therapy that blocks relevant signaling pathways results in the prevention of further tumor growth and leads to an expressive decrease in its size (82% in the simulation).

Targeting Signaling Pathway Networks in Several Malignant Tumors: Progresses and Challenges

Malignant tumors remain the health problem of highest concern among people worldwide due to its high mortality and recurrence. Lung, gastric, liver, colon, and breast cancers are among the top five malignant tumors in terms of morbidity and mortality. In cancer biology, aberrant signaling pathway regulation is a prevalent theme that drives the generation, metastasis, invasion, and other processes of all malignant tumors. The Wnt/β-catenin, PI3K/AKT/mTOR, Notch and NF-kB pathways are widely concerned and signal crosstalks exist in the five solid tumors. This review provides an innovative summary of the recent progress in research on these signaling pathways, the underlying mechanism of the molecules involved in these pathways, and the important role of some miRNAs in tumor-related signaling pathways. It also presents a brief review of the antitumor molecular drugs that target these signaling pathways. This review may provide a theoretical basis for the study of the molecular biological mechanism of malignant tumors and vital information for the development of new treatment strategies with a focus on efficacy and the reduction of side effects.

Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids

The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.

Phosphatidylinositol 3-kinase (PI3K) inhibitors: a recent update on inhibitor design and clinical trials (2016-2020)

Introduction: The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway plays a central role in regulating cell growth and proliferation and thus has been considered as effective anticancer drug targets. Many PI3K inhibitors have been developed and progressed to various stages of clinical trials, and some have been approved as anticancer treatment. In this review, we discuss the drug design and clinical development of PI3K inhibitors over the past 4 years. We review the selectivity and potency of 47 PI3K inhibitors. Structural determinants for increasing selectivity toward PI3K subtype-selectivity or mutant selectivity are discussed. Future research direction and current clinical development in combination therapy of inhibitors involved in PI3Ks are also discussed.Area covered: This review covers clinical trial reports and patent literature on PI3K inhibitors and their selectivity published between 2016 and 2020.Expert opinion: To PI3Kα mutants (E542K, E545K, and H1047R), it is highly desirable to design and develop mutant-specific PI3K inhibitors. It is also necessary to develop subtype-selective PI3Kα inhibitors to minimize toxicity. To reduce drug resistance and to improve efficacy, future studies should include combination therapy of PI3K inhibitors with existing anticancer drugs from different pathways.

Complement C3a activates osteoclasts by regulating the PI3K/PDK1/SGK3 pathway in patients with multiple myeloma

OBJECTIVE

Myeloma bone disease (MBD) is the most common complication of multiple myeloma (MM). Our previous study showed that the serum levels of C3/C4 in MM patients were significantly positively correlated with the severity of bone disease. However, the mechanism of C3a/C4a in osteoclasts MM patients remains unclear.

METHODS

The formation and function of osteoclasts were analyzed after adding C3a/C4a in vitro. RNA-seq analysis was used to screen the potential pathways affecting osteoclasts, and the results were verified by Western blot, qRT-PCR, and pathway inhibitors.

RESULTS

The osteoclast area per view induced by 1 μg/mL (mean ± SD: 50.828 ± 12.984%) and 10 μg/mL (53.663 ± 12.685%) of C3a was significantly increased compared to the control group (0 μg/mL) (34.635 ± 8.916%) (P < 0.001 and P < 0.001, respectively). The relative mRNA expressions of genes, OSCAR/TRAP/RANKL/cathepsin K, induced by 1 μg/mL (median: 5.041, 3.726, 1.638, and 4.752, respectively) and 10 μg/mL (median: 5.140, 3.702, 2.250, and 5.172, respectively) of C3a was significantly increased compared to the control group (median: 3.137, 2.004, 0.573, and 2.257, respectively) (1 μg/mL P = 0.001, P = 0.003, P < 0.001, and P = 0.008, respectively; 10 μg/mL: P < 0.001, P = 0.019, P < 0.001, and P = 0.002, respectively). The absorption areas of the osteoclast resorption pits per view induced by 1 μg/mL (mean ± SD: 51.464 ± 11.983%) and 10 μg/mL (50.219 ± 12.067%) of C3a was also significantly increased (33.845 ± 8.331%) (P < 0.001 and P < 0.001, respectively) compared to the control. There was no difference between the C4a and control groups. RNA-seq analysis showed that C3a promoted the proliferation of osteoclasts using the phosphoinositide 3-kinase (PI3K) signaling pathway. The relative expressions of PIK3CA/phosphoinositide dependent kinase-1 (PDK1)/serum and glucocorticoid inducible protein kinases (SGK3) genes and PI3K/PDK1/p-SGK3 protein in the C3a group were significantly higher than in the control group. The activation role of C3a in osteoclasts of MM patients was reduced by the SGK inhibitor (EMD638683).

CONCLUSIONS

C3a activated osteoclasts by regulating the PI3K/PDK1/SGK3 pathways in MM patients, which was reduced using a SGK inhibitor. Overall, our results identified potential therapeutic targets and strategies for MBD patients.

High frequency of PIK3CA and TERT promoter mutations in fibromatosis-like spindle cell carcinomas

AIMS

Fibromatosis-like spindle cell carcinomas (FLSCCs) are rare metaplastic breast cancers (MBCs) that are characterised by bland spindle cells in a collagenous stroma. Although some MBCs are highly malignant, FLSCCs have indolent behaviour with low potential for lymph node or distant metastasis. Owing to their rarity, there are limited genomic data on FLSCCs. In this study, we analysed the clinicopathological features and molecular characteristics of four FLSCCs to elucidate the pathogenesis of these rare tumours.

METHODS AND RESULTS

Four pure FLSCCs were sequenced by DIAN (Hangzhou Lab) using a 324-gene platform (FoundationOne CDx) with licensed technologies. The results showed that most FLSCCs harboured the pathogenic H1047R mutation in PIK3CA (3/4, 75%) and the -124C>T mutation in the telomerase reverse transcriptase (TERT) promoter (3/4, 75%). No copy number variations were observed in any cases in our study.

CONCLUSIONS

Our study showed that PIK3CA and TERT promoter mutations were common genetic features of FLSCCs. These findings contribute to our understanding of FLSCCs biology.

Targeting the PI3K and MAPK pathways to improve response to HER2-targeted therapies in HER2-positive gastric cancer

Background

Aberrant PI3K signalling is implicated in trastuzumab resistance in HER2-positive gastric cancer (GC). The role of PI3K or MEK inhibitors in sensitising HER2-positive GCs to trastuzumab or in overcoming trastuzumab resistance is unclear.

Methods

Using mass spectrometry-based genotyping we analysed 105 hotspot, non-synonymous somatic mutations in PIK3CA and ERBB-family (EGFR, ERBB2, ERBB3 and ERBB4) genes in gastric tumour samples from 69 patients. A panel of gastric cell lines (N87, OE19, ESO26, SNU16, KATOIII) were profiled for anti-proliferative response to the PI3K inhibitor copanlisib and the MEK1/2 inhibitor refametinib alone and in combination with anti-HER2 therapies.

Results

Patients with HER2-positive GC had significantly poorer overall survival compared to HER2-negative patients (15.9 months vs. 35.7 months). Mutations in PIK3CA were only identified in HER2-negative tumours, while ERBB-family mutations were identified in HER2-positive and HER2-negative tumours. Copanlisib had anti-proliferative effects in 4/5 cell lines, with IC50s ranging from 23.4 (N87) to 93.8 nM (SNU16). All HER2-positive cell lines except SNU16 were sensitive to lapatinib (IC50s 0.04 µM–1.5 µM). OE19 cells were resistant to trastuzumab. The combination of lapatinib and copanlisib was synergistic in ESO-26 and OE-19 cells (ED50: 0.83 ± 0.19 and 0.88 ± 0.13, respectively) and additive in NCI-N87 cells (ED50:1.01 ± 0.55). The combination of copanlisib and trastuzumab significantly improved growth inhibition compared to either therapy alone in NCI-N87, ESO26 and OE19 cells (p < 0.05).

Conclusions

PI3K or MEK inhibition alone or in combination with anti-HER2 therapy may represent an improved treatment strategy for some patients with HER2-positive GC, and warrants further investigation in a clinical trial setting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-02842-1.

HDAC6 inhibitor WT161 performs anti-tumor effect on osteosarcoma and synergistically interacts with 5-FU

BACKGROUND

WT161, as a selective HDAC6 inhibitor, has been shown to play anti-tumor effects on several kinds of cancers. The aim of the present study is to explore the roles of WT161 in osteosarcoma and its underlying mechanisms.

METHODS

The anti-proliferative effect of WT161 on osteosarcoma cells was examined using MTT assay and colony formation assay. Cell apoptosis was analyzed using flow cytometer. The synergistic effect was evaluated by isobologram analysis using CompuSyn software. The osteosarcoma xenograft models were established to evaluate the anti-proliferative effect of WT161 in vivo.

RESULTS

WT161 suppressed the cell growth and induced apoptosis of osteosarcoma cells in a dose- and time-dependent manner. Mechanistically, we found that WT161 treatment obviously increased the protein level of PTEN and decreased the phosphorylation level of protein kinase-B (AKT). More importantly, WT161 showed synergistic inhibition with 5-FU on osteosarcoma cells in vitro and in vivo.

CONCLUSIONS

These results indicate that WT161 inhibits the growth of osteosarcoma through PTEN and has a synergistic efficiency with 5-FU.

Identification of hub genes associated with obesity-induced hepatocellular carcinoma risk based on integrated bioinformatics analysis

Obesity, which has become one of the biggest public health problems of the twenty-first century, accompanies many chronic conditions, including cancer. On the other hand, liver cancer, which is known to be associated with obesity, is considered another serious threat to public health. However, the underlying drivers of the development of obesity-associated hepatocellular carcinoma (HCC) remain blurry. The current study attempted to identify the key genes and pathways in the obesity-induced development of HCC using integrated bioinformatics analyses. Obesity and HCC-associated gene expression datasets were downloaded from Gene Expression Omnibus (GEO) and analyzed to identify overlapping differentially expressed genes (DEGs) and hub genes. The prognostic potentials, survival analysis, and expression levels of hub genes were further assessed. Moreover, the correlation between hub genes and the immune cells infiltration was analyzed. The findings of this research revealed that both mRNA and protein expression levels of the four hub genes (IGF1, ACADL, CYP2C9, and G6PD) involved in many important metabolic pathways are remarkably altered in both obese individuals and patients with HCC. The results demonstrated that these dysregulated genes in both obesity and HCC may serve as considerable targets for the prevention and treatment of HCC development in obese individuals.

How can we turn the PI3K/AKT/mTOR pathway down? Insights into inhibition and treatment of cancer

Introduction: The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a fundamental regulator of cell proliferation and survival. Dysregulation in this pathway leads to the development of cancer. Accumulating evidence indicates that dysregulation in this pathway is involved in cancer initiation, progression, and recurrence. However, the pathway consists of various signal transducing factors related with cellular events, such as transformation, tumorigenesis, cancer progression, and drug resistance. Therefore, it is very important to determine the targets in this pathway for cancer therapy. Although many drugs inhibiting this signaling pathway are in clinical trials or have been approved for treating solid tumors and hematologic malignancies, further understanding of the signaling mechanism is required to achieve better therapeutic efficacy.Areas covered: In this review, we have describe the PI3K/AKT/mTOR pathway in detail, along with its critical role in cancer stem cells, for identifying potential therapeutic targets. We also summarize the recent developments in different types of signaling inhibitors.Expert opinion: Downregulation of the PI3K/AKT/mTOR pathway is very important for treating all types of cancers. Thus, further studies are required to establish novel prognostic factors to support the current progress in cancer treatment with emphasis on this pathway.

Discovery of novel dihydroartemisinin-cinnamic hybrids inducing lung cancer cells apoptosis via inhibition of Akt/Bad signal pathway

A series of dihydroartemisinin-cinnamic acid hybrids were designed, synthesized and evaluated. Most of the tested compounds showed enhanced anti-proliferative activities than artemisinin and dihydroartemisinin, among which 16 g had the superior potency with IC₅₀ values ranging from 5.07 μM to 7.88 μM against four tested cancer cell lines. The cell cycle arrest revealed that 16 g induced A549 cell cycle arrest at G0/G1 phase via regulation of G1-related protein expression (Cdk4). Further mechanism studies reveal that 16 g induced A549 cells apoptosis via inhibiting Akt/Bad pathway. Moreover, 16 g depolarized the mitochondria membrane potentials and induced ROS generation in A549. Additionally, 16 g blocked migration of A549 cells in a concentration-dependent manner. What's more, 16 g is barely nontoxic to zebrafish embryos. Overall, the cell cycle arrest, inhibition of Akt/Bad signal pathway, ROS generation and migration blocked might explain the potent anti-proliferative activities of these compounds.

CCL26 is upregulated by nab-paclitaxel in pancreatic cancer-associated fibroblasts and promotes PDAC invasiveness through activation of the PI3K/AKT/mTOR pathway

Recently, the combined use of FOLFIRINOX (leucovorin and fluorouracil plus irinotecan and oxaliplatin) and gemcitabine plus nab-paclitaxel has significantly improved the prognosis of patients with pancreatic cancer. However, there is still a high proportion of patients who develop metastatic pancreatic cancer in the course of chemotherapy or within a short period after chemotherapy. Previous reports have shown that chemotherapy-driven cytokine storms or the direct effects of certain chemotherapeutics on stromal and/or immune cells collectively change the microenvironment of the primary tumor, thus indirectly promoting metastasis. However, the mechanism underlying chemotherapy-induced metastasis in the course of chemotherapy, and afterwards, remains elusive in pancreatic cancer. In the present study, we aimed to determine the expression of CCL26 in the pancreatic cancer-associated fibroblasts (CAFs) after nab-paclitaxel treatment and to explore the role of CCL26 in the pancreatic adenocarcinoma (PDAC) invasion. Our results showed that nab-paclitaxel increased CCL26 mRNA and protein expression levels in a dose- and time-dependent manner. Subsequently, PDAC cell lines were treated with recombinant CCL26 for 48 h. The transwell migration assay showed that recombinant CCL26 enhanced the invasion of PDAC cells. Western blot analysis showed that the protein expression levels of phospho-(p-)PI3K, p-AKT, and p-mTOR were increased by CCL26 in PDAC cells. CCL26 expressions in 95 PDAC tissues and adjacent normal tissues were evaluated using reverse transcription-quantitative polymerase chain reaction and immunohistochemistry. CCL26 was found to be overexpressed in PDAC samples, and upregulated CCL26 expression was significantly associated with advanced perineural invasion, lymph node metastasis, and poor differentiation. In summary, our results showed that nab-paclitaxel increased the expression of CCL26 in CAFs, and CCL26 enhanced the invasive potential of pancreatic cancer cells by activating the PI3K/AKT/mTOR axis. Thus, CCL26 may be a potential prognostic biomarker for pancreatic cancer.

Actin-Like Protein 8 Promotes the Progression of Triple-Negative Breast Cancer via Activating PI3K/AKT/mTOR Pathway

Objective

The purpose of this study was to investigate the function of actin-like protein 8 (ACTL8) on triple-negative breast cancer (TNBC) and its potential mechanisms.

Methods

In our study, ACTL8 expression and the prognostic values of ACTL8 were evaluated via the dataset from the Cancer Genome Atlas (TCGA). At the same time, the expression of ACTL8 in TNBC cells was measured by Western blot and qRT-PCR. Then, the effects of ACTL8 on the growth and metastasis of TNBC were investigated by using 5-ethynyl-20-deoxyuridine (EdU), colony formation, flow cytometry, wound healing and transwell assays. Mechanistically, Western blot was performed to confirm the interaction between ACTL8 and phosphatidylinositol 3′-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway in TNBC.

Results

ACTL8 expression was upregulated in TNBC and associated with the poor prognosis of TNBC. Silencing ACTL8 suppressed the proliferation, migration and invasion, also promoted the apoptosis in MDA-MB-231 and BT-549 cells. Moreover, we found that silencing ACTL8 could inhibit the activation of PI3K/AKT/mTOR signaling pathway in MDA-MB-231 and BT-549 cells. Meanwhile, the impact of silencing ACTL8 on the proliferation, apoptosis, migration and invasion was enhanced by PI3K/AKT/mTOR pathway inhibitor (Wortmannin) and reversed by PI3K/AKT/mTOR pathway activator (740Y-P).

Conclusion

Our data demonstrated that ACTL8 may facilitate the proliferation, migration and invasion, while inhibiting apoptosis through activating PI3K/Akt/mTOR signaling pathway in TNBC.

Molecular genetics of meningiomas

Comprehensive genomic studies of meningioma have offered important insights about the molecular mechanisms underlying this common brain tumor. The use of next-generation sequencing techniques has identified driver mutations in approximately 80% of benign sporadic lesions, as well as epigenetic, regulatory, and copy number events that are associated with formation and disease progression. The events described to date fall into five mutually exclusive molecular subgroups that correlate with tumor location and embryological origin. Importantly, these subgroups also carry implications for clinical management, as they are predictive of histologic subtype and the likelihood of progression. Further work is necessary to understand the molecular mechanisms by which identified mutations drive tumorigenesis as well as the genomic pathways that transform benign lesions into malignancies. Progress made during the past decade has opened the door to potential molecular therapies as well as integration of meningioma genotyping data into clinical management decisions. Several pharmacologic trials are currently underway that leverage recent genomic findings to target established oncogenic pathways in refractory tumors. With the combined efforts of physicians and basic science investigators, the clinical management of meningioma will continue to make important strides in the coming years.

4-Acetylantrocamol LT3 Inhibits Glioblastoma Cell Growth and Downregulates DNA Repair Enzyme O6-Methylguanine-DNA Methyltransferase

Glioblastoma multiforme (GBM) is a deadly malignant brain tumor that is resistant to most clinical treatments. Novel therapeutic agents that are effective against GBM are required. Antrodia cinnamomea has shown antiproliferative effects in GBM cells. However, the exact mechanisms and bioactive components remain unclear. Thus, the present study aimed to investigate the effect and mechanism of 4-acetylantrocamol LT3 (4AALT3), a new ubiquinone from Antrodia cinnamomeamycelium, in vitro. U87 and U251 cell lines were treated with the indicated concentration of 4AALT3. Cell viability, cell colony-forming ability, migration, and the expression of proteins in well-known signaling pathways involved in the malignant properties of glioblastoma were then analyzed by CCK-8, colony formation, wound healing, and western blotting assays, respectively. We found that 4AALT3 significantly decreased cell viability, colony formation, and cell migration in both in vitro models. The epidermal growth factor receptor (EGFR), phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR), Hippo/yes-associated protein (YAP), and cAMP-response element binding protein (CREB) pathways were suppressed by 4AALT3. Moreover, 4AALT3 decreased the level of DNA repair enzyme O⁶-methylguanine-DNA methyltransferase and showed a synergistic effect with temozolomide. Our findings provide the basis for exploring the beneficial effect of 4AALT3 on GBM in vivo.

Insulin Exacerbates Inflammation in Fibroblast-Like Synoviocytes

Osteoarthritis (OA) is considered the most frequent degenerative disease and is characterized by cartilage degradation and synovial inflammation. Fibroblast-like synoviocytes (FLSs) are vital to synovial inflammation in OA. Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and hyperinsulinemia (HINS) and has been demonstrated to be an independent risk factor for OA. Autophagy is involved in the processes of various inflammatory diseases, and autophagy inhibition can stimulate OA development. Thus, we aimed to investigate the role of insulin in the inflammatory phenotype and autophagy of FLSs in OA. The data showed that cell viability and proinflammatory cytokine production in FLSs were both increased after insulin stimulation. We also found that high insulin could promote macrophage infiltration and chemokine production but inhibited autophagy in FLSs. To further explore the potential mechanisms, the effects of insulin on PI3K/Akt/mTOR and NF-ĸB signaling activation were evaluated. The results indicated that insulin activated PI3K/Akt/mTOR/NF-ĸB signaling, and the above-mentioned inflammatory responses, including autophagy inhibition, were notably attenuated by specific signaling inhibitors in the presence of high insulin. Moreover, the data showed that a positive feedback loop existed between proinflammatory cytokines (e.g., IL-1β, IL-6, and TNF-α) and PI3K/mTOR/Akt/NF-ĸB signaling in FLSs, and insulin enhanced this feedback loop to accelerate OA progression. Our study suggests that insulin may be a novel therapeutic strategy for OA prevention and treatment in the future.

Reciprocal regulation of cellular mechanics and metabolism

Metabolism and mechanics are intrinsically intertwined. External forces, sensed through the cytoskeleton or distortion of the cell and organelles, induce metabolic changes in the cell. The resulting changes in metabolism, in turn, feed back to regulate every level of cell biology, including the mechanical properties of cells and tissues. Here we examine the links between metabolism and mechanics, highlighting signalling pathways involved in the regulation and response to cellular mechanosensing. We consider how forces and metabolism regulate one another through nanoscale molecular sensors, micrometre-scale cytoskeletal networks, organelles and dynamic biomolecular condensates. Understanding this cross-talk will create diagnostic and therapeutic opportunities for metabolic disorders such as cancer, cardiovascular pathologies and obesity.

DHEA inhibits proliferation, migration and alters mesenchymal-epithelial transition proteins through the PI3K/Akt pathway in MDA-MB-231 cells

Cancer is one of the leading causes of death worldwide, and breast cancer is the most common among women. Dehydroepiandrosterone (DHEA), the most abundant steroid hormone in human serum, inhibits proliferation and migration of breast cancer cells, modulating the expression of proteins involved in mesenchymal-epithelial transition (MET). However, the underlying molecular mechanisms are not fully understood. DHEA effects on the triple-negative breast cancer cell line MDA-MB-231 (mesenchymal stem-like) could be exerted by binding to receptors tyrosine kinase (RTKs) and signaling through MEK/ERK and/or PI3K/Akt pathways. In this study, MDA-MB-231 cells were exposed to DHEA in the presence of pharmacological inhibitors of these pathways and a siRNA against PIK3CA gene, which blocks PI3K pathway. Cell proliferation was measured by crystal violet staining, migration by the wound healing and transwell assays, and MET protein expression by western blot. A xenograft tumor growth in nude mice (nu^-/nu^-) using a siRNA against PI3K was also performed. Results showed that neither of the inhibitors used reverted the antiproliferative activity of DHEA. However, wortmannin and LY294002, inhibitors of the PI3K/Akt pathway, abolished the up- and down-regulation of E- and N-cadherin expression respectively, and inhibition of migration induced by DHEA in MDA-MB-231 cells. The siRNA that blocks the PI3K pathway, abolished the effects of DHEA on proliferation, migration, MET proteins expression and the growth of tumors in nude mice. In conclusion, these results suggest that PI3K/Akt pathway participates in the effects of DHEA on breast cancer cells.

CUDC-101 enhances the chemosensitivity of gemcitabine-treated lymphoma cells

BACKGROUND

The metastasis and recurrence of Non-Hodgkin's lymphoma (NHL) is a major cause of morbidity and mortality. Recent work suggests that drugs capable of targeting epigenetic regulatory mechanisms may be well suited to the treatment of such disease progression.

METHODS

This study was thus designed to evaluate the ability of the novel histone deacetylase (HDAC) inhibitor CUDC-101 to synergize with gemcitabine in order to kill human HUT78 and Pfeiffer NHL cells. To that end, we analyzed the viability of these NHL cells via CCK-8 assay, while the incidence of apoptosis among treated cells was evaluated via Annexin V-FITC/PI staining and by the Western blotting-mediated evaluation of proteins associate with apoptosis and related signaling pathways.

RESULTS

We found that CUDC-101 and gemcitabine interacted synergistically to reduce NHL cell viability and to induce the apoptotic death of these cells via the EGFR/ PI3K/Akt and Erk pathways, which were regulated by HDAC signaling pathways.

CONCLUSION

Together, our results highlight the anti-cancer properties of CUDC-101 alone or in combination with gemcitabine as an approach to inducing the apoptotic death of lymphoma cells in vitro, while also offering insight into the underlying molecular mechanisms governing this activity.

Mechanisms of Resistance to PI3K Inhibitors in Cancer: Adaptive Responses, Drug Tolerance and Cellular Plasticity

The phosphatidylinositol-3-kinase (PI3K) pathway plays a central role in the regulation of several signalling cascades which regulate biological processes such as cellular growth, survival, proliferation, motility and angiogenesis. The hyperactivation of this pathway is linked to tumour progression and is one of the most common events in human cancers. Additionally, aberrant activation of the PI3K pathway has been demonstrated to limit the effectiveness of a number of anti-tumour agents paving the way for the development and implementation of PI3K inhibitors in the clinic. However, the overall effectiveness of these compounds has been greatly limited by inadequate target engagement due to reactivation of the pathway by compensatory mechanisms. Herein, we review the common adaptive responses that lead to reactivation of the PI3K pathway, therapy resistance and potential strategies to overcome these mechanisms of resistance. Furthermore, we highlight the potential role in changes in cellular plasticity and PI3K inhibitor resistance.

Properties of FDA-approved small molecule phosphatidylinositol 3-kinase inhibitors prescribed for the treatment of malignancies

The discovery of the phosphatidylinositol 3-kinase (PI 3-kinase) pathway was a major advance in understanding eukaryotic signal transduction. The high frequency of PI 3-kinase pathway mutations in many cancers stimulated the development of drugs targeting these oncogenic mutants. The PI 3-kinases are divided into three classes and Class I PI 3-kinases, which catalyze the phosphorylation of phosphatidylinositol-4,5-bisphosphate (PI-4,5-P2) to generate phosphatidylinositol-3,4,5-trisphosphate (PIP3), are the main subject of this review. The class I PI 3-kinases are made up of p110α, p110β, p110δ, and p110γ catalytic subunits. These catalytic subunits are constitutively bound to regulatory subunits (p85α, p85β, p55γ, p101, and p87 proteins). The p85/p55 regulatory subunits heterodimerize with p110α or p110δ thereby forming complexes that are regulated chiefly by receptor protein-tyrosine kinases. The p101 and p87 subunits heterodimerize with p110γ to form complexes that are regulated mainly by G protein-coupled receptors (GPCRs). Complexes containing the p110β subunit are activated by receptor protein-tyrosine kinases as well as GPCRs. Following the generation of PIP3, the AKT and mTOR protein-serine/threonine kinases are activated leading to cell growth, proliferation, and survival. Like protein kinases, the PI 3-kinase domains consist of a bilobed structure connected by a hinge-linker segment. ATP and most PI 3-kinase and protein kinase inhibitors form hydrogen bonds with hinge residues. The small and large lobes of PI 3-kinases and protein kinases have a very similar three-dimensional structure called the protein kinase fold. Both PI 3-kinases and eukaryotic protein kinases possess an activation segment that begins with a DFG triad (Asp-Phe-Gly); the activation segment of protein kinases usually ends with an APE (Ala-Pro-Glu) signature while that of PI 3-kinases ends with a PFxLT (Pro-Phe-Xxx-Leu-Thr) signature. Dormant PI 3-kinases have a collapsed activation loop and active PI 3-kinases have an extended activation loop. The distance between the α-carbon atom of the DFG-D residue at the beginning of the activation loop and that of the PFxLT-F residue at the end of the activation loop in dormant PI 3-kinases is about 13 Å; this distance in active PI 3-kinases is about 18 Å. The protein kinase catalytic loop has an HRD (His-Arg-Asp) signature while that of the PI 3-kinases reverses the order with a DRH triad. Alpelisib is an orally effective FDA-approved PI 3-kinase-α inhibitor used for the treatment of breast cancer. Copanlisib, duvelisib, idelalisib, and umbralisib are PI 3-kinase-δ inhibitors that are approved for the third-line treatment of follicular lymphomas and other hematological disorders. Copanlisib is also a potent inhibitor of PI 3-kinase-α. Of the five approved drugs, all are orally bioavailable except copanlisib. Idelalisib interacts with the active conformation of PI 3-kinase-δ and is classified as a type I inhibitor. Alpelisib and copanlisib interact with inactive PI 3-kinase-α and PI 3-kinase-γ, respectively, and are classified as a type I½ antagonists. Except for umbralisib with a molecular weight of 571.5, all five drugs conform to the Lipinski rule of five for oral effectiveness. Copanlisib, however, must be given intravenously. Alpelisib and copanlisib inhibit PI 3-kinase-α, which is involved in insulin signaling, and both drugs promote insulin-resistance and produce hyperglycemia. The five FDA-approved PI 3-kinase inhibitors produce significant on-target toxicities, more so than many approved protein kinase antagonists. The development of PI 3-kinase inhibitors with fewer toxicities is an important long-term therapeutic goal.

Oral PI3K-δ,γ Inhibitor for the Management of People with Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma: A Narrative Review on Duvelisib

The development of highly effective targeted therapies has led to a new treatment paradigm in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL). Despite these advances, many patients will eventually require alternative treatment strategies due to the emergence of tolerability issues or resistance to these novel agents. Duvelisib is a first-in-class, potent oral agent with dual inhibitor activity against the δ and γ isoforms of phosphoinositide 3-kinase (PI3Kδ and PI3Kγ), which are specific to the hematopoietic system. Dysregulation of the PI3K/PTEN/AKT/mTOR pathway has been implicated in cancer cell growth, survival and metabolism and has been the subject of cancer drug development in recent years. Duvelisib demonstrated activity in CLL/SLL in early trials, leading to further evaluation in the Phase 3 DUO trial that compared duvelisib against ofatumumab in patients with relapsed/refractory CLL/SLL. This trial led to the Food and Drug Administration (FDA) approval for the treatment of adult patients with CLL/SLL after at least two prior lines of therapy. The major reason for therapy discontinuation is the development of serious adverse events, which include severe infections and diarrhea/colitis, precluding its widespread use. Ongoing clinical trials are evaluating duvelisib in combination strategies and with alternate dosing schedules in patients with CLL/SLL. With close monitoring, duvelisib can be a promising drug for the treatment of patients with relapsed or refractory CLL/SLL. This review summarizes the relevant clinical data from recent clinical advances in CLL and aims to interpret the duvelisib trials while exploring strategies to improve its use and adverse event management in the era of novel targeted agents.

Somatic MAP3K3 and PIK3CA mutations in sporadic cerebral and spinal cord cavernous malformations

Cavernous malformations (CMs) affecting the central nervous system occur in approximately 0.16% to 0.4% of the general population. The majority (85%) of the CMs are in a sporadic form, but the genetic background of sporadic CMs remains enigmatic. Of the 81 patients, 73 (90.1%) patients were detected carrying somatic missense variants in 2 genes: MAP3K3 and PIK3CA by whole-exome sequencing (WES). The mutation spectrum correlated with lesion size (P = 0.001), anatomical distribution (P < 0.001), MRI appearance (P = 0.004) and haemorrhage events (P = 0.006). PIK3CA mutation was a significant predictor of overt haemorrhage events (P = 0.003, OR = 11.252, 95% CI = 2.275-55.648). Enrichment of endothelial cell (EC) population was associated with a higher fractional abundance of the somatic mutations. Overexpression of the MAP3K3 mutation perturbed angiogenesis of EC models in vitro and zebrafish embryos in vivo. Distinct transcriptional signatures between different genetic subgroups of sporadic CMs were identified by single-cell RNA-sequencing (scRNA-seq) and verified by pathological staining. Significant apoptosis in MAP3K3 mutation carriers and overexpression of GDF15 and SERPINA5 in PIK3CA mutation carriers contributed to their phenotype. We identified activating MAP3K3 and PIK3CA somatic mutations in the majority (90.1%) of sporadic CMs and PIK3CA mutations could confer a higher risk for overt haemorrhage. Our data provide insights into genomic landscapes, propose a mechanistic explanation and underscore the possibility of a molecular classification for sporadic CMs.

Cell signaling pathways as molecular targets to eliminate AML stem cells

Acute myeloid leukemia (AML) remains the most lethal of leukemias and a small population of cells called leukemic stem cells (LSCs) has been associated with disease relapses. Some cell signaling pathways play an important role in AML survival, proliferation and self-renewal properties and are abnormally activated or suppressed in LSCs. This includes the NF-κB, Wnt/β-catenin, Hedgehog, Notch, EGFR, JAK/STAT, PI3K/AKT/mTOR, TGF/SMAD and PPAR pathways. This review aimed to discuss these pathways as molecular targets for eliminating AML LSCs. Herein, inhibitors/activators of these pathways were summarized as a potential new anti-AML therapy capable of eliminating LSCs to guide future researches. The clinical use of cell signaling pathways data can be useful to enhance the anti-AML therapy.

Gigantol inhibits proliferation and enhances DDP-induced apoptosis in breast-cancer cells by downregulating the PI3K/Akt/mTOR signaling pathway

AIMS

Gigantol is a bibenzyl compound isolated from orchids of the genus Dendrobium. Gigantol has been demonstrated to possess various pharmacologic (including anticancer) effects. Cisplatin (DDP) has been used and studied as the first-line agent for breast cancer (BC) treatment. Often, its efficacy is jeopardized due to intolerance and organ toxicity. We investigated if gigantol could enhance the anticancer effects of DDP in BC cells and its underlying mechanism of action.

MAIN METHODS

The potential pathway of gigantol in BC cells was detected by network-pharmacology and molecular-docking studies. The proliferation and apoptosis of BC cell lines were measured by the MTT assay, colony formation, Hoechst-33342 staining, and flow cytometry. Protein expression was measured by western blotting.

KEY FINDINGS

Gigantol could inhibit proliferation of BC cells and enhance DDP-induced apoptosis. According to the results of western blotting, gigantol reinforced DDP-induced anticancer effects through downregulation of the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling pathway in BC cells. The effects were consistent with those of the pathway inhibitor LY294002.

SIGNIFICANCE

Our data might provide new insights into the underlying antitumor effect of gigantol in BC cells. This enhancement effect in the combination of gigantol and DDP may provide many therapeutic benefits in clinical treatment regimens against BC.

Biological Heterogeneity of Chondrosarcoma: From (Epi) Genetics through Stemness and Deregulated Signaling to Immunophenotype

Chondrosarcoma (ChS) is a primary malignant bone tumor. Due to its heterogeneity in clinical outcomes and resistance to chemo- and radiotherapies, there is a need to develop new potential therapies and molecular targets of drugs. Many genes and pathways are involved in in ChS progression. The most frequently mutated genes are isocitrate dehydrogenase ½ (IDH1/2), collagen type II alpha 1 chain (COL2A1), and TP53. Besides the point mutations in ChS, chromosomal aberrations, such as 12q13 (MDM2) amplification, the loss of 9p21 (CDKN21/p16/INK4A and INK4A-p14ARF), and several gene fusions, commonly occurring in sarcomas, have been found. ChS involves the hypermethylation of histone H3 and the decreased methylation of some transcription factors. In ChS progression, changes in the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K-AKT-mTOR) and hedgehog pathways are known to play a role in tumor growth and chondrocyte proliferation. Due to recent discoveries regarding the potential of immunotherapy in many cancers, in this review we summarize the current state of knowledge concerning cellular markers of ChS and tumor-associated immune cells. This review compares the latest discoveries in ChS biology from gene alterations to specific cellular markers, including advanced molecular pathways and tumor microenvironment, which can help in discovering new potential checkpoints in inhibitory therapy.

Lessons, Challenges and Future Therapeutic Opportunities for PI3K Inhibition in CLL

Simple Summary

The phosphoinositide 3-kinase (PI3K) is a family of kinases that play a key role in the biology of chronic lymphocytic leukemia (CLL). Inhibitors of PI3K demonstrated efficacy in the treatment of CLL, associated with significant adverse events that limited the clinical use of this drugs. In this review, we underlined the relevance of PI3K inhibitors in CLL, we collected recent data about the use of these molecules in clinical practice and in clinical trial discussing strategies for the management of adverse events, which could help to improve the use of these therapies in the treatment of CLL.

Abstract

Chronic lymphocytic leukemia (CLL) shows constitutive phosphatidylinositol 3-kinase (PI3K) activation resulting from aberrant regulation of the B-cell receptor (BCR) signaling. PI3K inhibitors have been evaluated in CLL therapy, bringing a new treatment opportunity for patients with this disease. Despite the proven therapeutic efficacy, the use of approved PI3K inhibitors is limited by severe immune-mediated toxicities and given the availability of other more tolerable agents. This article reviews the relevance of PI3K signaling and pharmacologic inhibition in CLL. Data on efficacy and toxicity of PI3K inhibitors are also presented, as well as strategies for overcoming barriers for their clinical use in CLL treatment.

PIK3CA Mutation Assessment in HR+/HER2− Metastatic Breast Cancer: Overview for Oncology Clinical Practice

Activation of the PI3K–AKT–mTOR pathway occurs in several human cancers, including hormone receptor (HR)-positive breast cancer (BC) where is associated with resistance to endocrine therapy and disease progression. In BC, the most common PI3K–AKT–mTOR pathway alteration is represented by PIK3CA oncogenic mutations. These mutations can occur throughout several domains of the p110α catalytic subunit, but the majority are found in the helical and kinase domains (exon 9 and 20) that represent the “hotspots”. Considering the central role of the PI3K–AKT–mTOR pathway in HR-positive BC, several inhibitors (both pan-PI3K and isoform-specific) have been developed and tested in clinical trials. Recently, the PI3Kα-selective inhibitor alpelisib was the first PI3K inhibitor approved for clinical use in HR-positive metastatic BC based on the results of the phase III SOLAR-1 trial. Several methods to assess PIK3CA mutational status in tumor samples have been developed and validated, including real-time polymerase chain reaction (PCR), digital droplet PCR (ddPCR), BEAMing assays, Sanger sequencing, and next-generation sequencing (NGS) panels. Several new challenges will be expected once alpelisib is widely available in a clinical setting, including the harmonization of testing procedures for the detection of PI3K–AKT–mTOR pathway alterations. Herein, we provide an overview on PI3K–AKT–mTOR pathway alterations in HR-positive BC, discuss their role in determining prognosis and resistance to endocrine therapy and highlight practical considerations about diagnostic methods for the detection of PI3K–AKT–mTOR pathway activation status.

Ganglioneuromas are driven by activated AKT and can be therapeutically targeted with mTOR inhibitors

Peripheral sympathetic nervous system tumors are the most common extracranial solid tumors of childhood and include neuroblastoma, ganglioneuroblastoma, and ganglioneuroma. Surgery is the only effective therapy for ganglioneuroma, which may be challenging due to the location of the tumor and involvement of surrounding structures. Thus, there is a need for well-tolerated presurgical therapies that could reduce the size and extent of ganglioneuroma and therefore limit surgical morbidity. Here, we found that an AKT–mTOR–S6 pathway was active in human ganglioneuroma but not neuroblastoma samples. Zebrafish transgenic for constitutively activated myr-Akt2 in the sympathetic nervous system were found to develop ganglioneuroma without progression to neuroblastoma. Inhibition of the downstream AKT target, mTOR, in zebrafish with ganglioneuroma effectively reduced the tumor burden. Our results implicate activated AKT as a tumorigenic driver in ganglioneuroma. We propose a clinical trial of mTOR inhibitors as a means to shrink large ganglioneuromas before resection in order to reduce surgical morbidity.

KRAS and BRAF mutations in Iranian colorectal cancer patients: A systematic review and meta-analysis

Background:

Mutations in the EGFR signaling pathway play an important role in the development of colorectal cancer (CRC). Mutations in these genes, like KRAS and BRAF, affect the treatment strategies and associated with poor prognosis and relative resistance to anti-EGFR therapies. Our aim was to conduct a systematic and meta-analysis on all studies that have been conducted on the prevalence of these gene mutations in Iranian CRC patients.

Methods:

Four science citation index databases (MEDLINE, EMBASE, Web of Science and Cochrane library) and local databases were searched up to March 2018 with related keywords. Two reviewers independently screened and extracted the data. Quality of all included studies was assessed using an adapted checklist from STROBE. A random-effect model was used to calculate the total prevalence of KRAS and BRAF mutations in CRC subjects by the event rate (ER). Meta-regression was utilized to explore heterogeneity causes.

Results:

In total, from 573 records, 23 eligible studies (2662 patients) were included for data extraction and analysis. In 18 of 23 included studies, the prevalence of KRAS mutations was 33.9% (95% CI=30.1-37.9) with I2=65.17 (p<0.001). The occurrence of KRAS mutations in codon 12 and 13 was 76.9% (95% CI = 70.4-82.3%) with I2=84.88 (p<0.001) and 23.5% (95% CI=17.9-30.3) with I2=85.85 (p<0.001), respectively. In 9 of 23 studies, the BRAF mutation rate was 3.2% (95% CI=0.003-13.6) with I2=88.61 (p<0.001).

Conclusion:

The prevalence of these mutations in CRC patients shows a significant difference in the different regions of Iran, which is probably due to environmental and racial factors.

R-Spondin 2 and WNT/CTNNB1 Signaling Pathways Are Required for Porcine Follicle Development and In Vitro Maturation

The secretion of oocyte-derived paracrine factors, such as R-spondin2, is an essential mechanism for follicle growth by promoting the proliferation and differentiation of cumulus cells around oocytes. In the present study, we aimed to identify the effect of R-spondin2 during follicular development. First, R-spondin2-related factors (R-spondin2, CTNNB1, LGR4, and LGR5) were identified through immunofluorescence in porcine ovarian tissue. CTNNB1 was expressed in ooplasm, and CTNNB1 and LGR4 were expressed in granulosa cells. In addition, R-spondin2, LGR4, and LGR5 were expressed in the theca interna. These results imply that these proteins play a major role in porcine follicular development. In addition, the effects of R-spondin2 on the in vitro maturation process of porcine cumulus oocyte complexes and subsequent embryonic development were confirmed. A treatment of 100 ng/mL R-spondin2 in the in vitro maturation (IVM) process increased nuclear maturation and increased the expression of EGFR mRNA in cumulus cells. The EGFR-ERK signal is essential for oocyte maturation, ovulation, and luteinization. R-spondin2 treatment also increased the expression of CTNNB1 and EGFR in primary cultured cumulus cells. In conclusion, RSPO2 and WNT/CTNNB1 signaling pathways are required for porcine follicle development and are predicted to be involved in the EGFR-ERK signaling pathway.

Acacetin and pinostrobin as a promising inhibitor of cancer-associated protein kinases

Protein kinases associated with cancer genes play vital role in angiogenesis, invasion, motility, proliferation, and survival. Therefore, cancer prevention/treatment, targeting kinases with phytochemicals could be a promising approach. Given potential of phytochemicals in modulating cancer-associated kinases, present study aims to find inhibitory prospects of selected flavonoids for cancer-chemoprevention/treatment. The molecular docking interaction analysis was done by exploring binding potential of flavonoids with kinases (PI3K, Akt, mTOR, EGFR, MAPK, MKK4, Fyn, ZAP-70, B-Raf, JAK-2, STAT-1, STAT-3, STAT-4, STAT-5, and VEGF) involved in various carcinogenesis phases. Among flavonoids acacetin showed highest binding-energy against JAK-2 following Fyn > VEGF > PI3K > MKK4 > MAPK > BRaf > STAT-5 > STAT-1 > STAT-4 whereas pinostrobin depicts higher binding-energy with JAK-2 followed by B-Raf > MKK4 > VEGF > PI3K > MAPK > STAT-1 > STAT-4 > STAT-5. Further, molecular-dynamic simulation revealed that pinostrobin interacted with JAK-2 protein with binding-energy of -25.068 ± 1.08 kJ/mol whereas acacetin interacted with both JAK-2 and Fyn with binding-energies of -23.466 ± 0.9508 kJ/mol and-8.935 ± 1.3108 kJ/mol respectively. High binding-energy, low inhibition-constant, and drug-likeness of acacetin and pinostrobin provide a clue for their usage as a JAK-2 inhibitor which could be useful for molecular/cell-target based in-vitro and in-vivo investigations.