Targeting the PI3K/Akt/mTOR pathway for breast cancer therapy

Navigating the complexity of PI3K/AKT pathway in HER-2 negative breast cancer: biomarkers and beyond

The results of the SOLAR-1 and CAPItello-291, highlight the benefit of the ɑ-selective phosphoinositide 3-Kinase Pathway inhibitor (PI3Ki) alpelisib and the AKT inhibitor (AKTi) capivasertib in patients with hormone receptor-positive (HR+)/Human Epidermal Growth Factor Receptor 2 (HER2)- negative metastatic breast cancer (mBC) that have PIK3CA/AKT1/PTEN tumour alterations. Although effective, these drugs are associated with significant toxicities, which often limit their use, particularly in frail patients. Following the recent incorporation of these agents into clinical practice, and with many others currently in development, significant challenges have emerged, particularly those regarding biomarkers for patient selection. This review will discuss biomarkers of response and their resistance to PI3K/AKT inhibitors (PI3K/AKTis) in HR+/HER- BC in early and advanced settings to ascertain which populations will most benefit from these drugs. Of the biomarkers that were analysed, such as PIK3CA, AKT, PTEN mutations, insulin levels, 18 F-FDG-PET/TC, only the PIK3CA-mutations (PIK3CA-mut) and the AKT pathway alterations seem to have a predictive value for treatments with alpelisib and capivasertib. However, due to the retrospective and exploratory nature of the study, the data did not provide conclusive results. In addition, the different methods used to detect PIK3CA/AKT1/PTEN alterations underline the fact that the optimal diagnostic companion has yet to be established. We have summarised the clinical data on the approved and discontinued agents targeting this pathway and have assessed the drugs development, successes, and failures. Finally, because of tumour heterogeneity, we emphasise the importance of reassessing the mutational status of PI3KCA in both metastatic tissue and blood at the time of disease progression to better tailor treatment for patients.

Root extract of Hemsleya amabilis Diels suppresses renal cell carcinoma cell growth through inducing apoptosis and G2/M phase arrest via PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hemsleya amabilis Diels, belongs to cucurbitaceae, was traditional Chinese medicine (TCM). It is widely used to treat various diseases. However, these diseases may contribute to the development of RCC.

AIM OF THE STUDY

investigated the anticancer activities of root extract of Hemsleya amabilis Diels (HRE), and elucidated the underlying molecular mechanism in vivo and in vitro.

MATERIALS AND METHODS

Dried Hemsleya amabilis Diels roots were extracted by ethyl acetate and used to treat RCC4, OS-RC-2 and ACHN cells. UHPLC-MS was used to analyze the chemical composition of the extract. CCK-8 and colony formation assay were used to investigate proliferation. PI staining was used to detect cell cycle. Annexin-V-FITC, AO/EB and TEM were used to evaluate apoptosis. Transwell and wound healing assays were used to evaluate migration and invasion. RNA-seq, Network pharmacology, autodocking for virtual screening and molecular dynamics simulation were used to analyze potential molecular mechanisms and active components of HRE inhibiting proliferation of RCC. LY294002 and UC2288 were used to inhibit PI3K and P21 expression, respectively. IGF-1 was used to activate PI3K. Xenograft tumor model was established to evaluate its anti-tumor potential in vivo. Immunohistochemistry and Western blot were used to test protein expression levels. H&E staining was used to explore the side effects of HRE in vivo. Applying bioinformatics to analyze the effect of P21 on RCC.

RESULTS

HRE consists of 739 compounds. CCK-8 and colony formation assay showed that HRE significantly inhibited RCC cells proliferation. PI staining indicated that HRE caused G2/M phase arrest. Annexin-V-FITC, AO/EB and TEM experiments revealed that HRE significantly promoted apoptosis of RCC cells. Transwell and wound healing assays showed that HRE can inhibit the migration and invasion of RCC cells. RNA-seq showed that HRE induced 230 gene changes. Network pharmacology analysis found the relationship between HRE-component-target-RCC. Auto-docking found that Epitulipinolide diepoxide in HRE can stably bind to PIK3CA (-7.22 kJ/mol), and molecular dynamics simulation verified the combination between Epitulipinolide diepoxide of PIK3CA. In RCC4 cells, pretreatment with IGF-1, attenuated HRE-induced apoptosis and G2/M arrest. When pretreated with PIK3 inhibitor LY294002, the opposite result appears. Pretreatment with CDKN1A (P21) inhibitor UC2288 attenuated HRE-induced G2/M arrest. Xenograft tumor model showed that HRE inhibited tumor growth. Western blot analysis indicated that HRE can regulating Bax, Bcl-2, PARP, cleared-PARP, Caspase-9, Caspase-8, Caspase-3, Survivin, Cyclin-B1, CDK1, N-cadherin, snail, slug, E-cadherin, MMP-9. Immunohistochemical staining showed that in the treated group, expression of E-cadherin, Bax, P21 was up-regulated, while N-cadherin, PI3K, AKT and Bcl-2 were down-regulated. H&E staining showed that compared to control groups, the main organs in the HRE-treated groups showed no histological abnormalities. The overall survival rate of RCC patients in the high-expression group of P21 was higher than in the low-expression group of P21 on bioinformatics analysis.

CONCLUSIONS

HRE inhibited RCC migration and invasion through EMT, and inhibited proliferation in vivo and in vitro. In addition, HRE inhibited proliferation through promoting apoptosis and P21-induced G2/M phase arrest via PI3K/AKT signaling pathway. Overall, these results suggest that HRE may be a promising chemotherapy agent for RCC.

Model-based prediction of effective target exposure for MEN1611 in combination with trastuzumab in HER2-positive advanced or metastatic breast cancer patients

MEN1611 is a novel orally bioavailable PI3K inhibitor currently in clinical development for patients with HER2-positive (HER2+) PI3KCA mutated advanced/metastatic breast cancer (BC) in combination with trastuzumab (TZB). In this work, a translational model-based approach to determine the minimum target exposure of MEN1611 in combination with TZB was applied. First, pharmacokinetic (PK) models for MEN1611 and TZB in mice were developed. Then, in vivo tumor growth inhibition (TGI) data from seven combination studies in mice xenograft models representative of the human HER2+ BC non-responsive to TZB (alterations of the PI3K/AkT/mTOR pathway) were analyzed using a PK-pharmacodynamic (PD) TGI model for co-administration of MEN1611 and TZB. The established PK-PD relationship was used to quantify the minimum effective MEN1611 concentration, as a function of TZB concentration, needed for tumor eradication in xenograft mice. Finally, a range of minimum effective exposures for MEN1611 were extrapolated to patients with BC, considering the typical steady-state TZB plasma levels in patients with BC following three alternative regimens (i.v. 4 mg/kg loading dose +2 mg/kg q1w, i.v. 8 mg/kg loading dose +6 mg/kg q3w or s.c. 600 mg q3w). A threshold of about 2000 ng·h/ml for MEN1611 exposure associated with a high likelihood of effective antitumor activity in a large majority of patients was identified for the 3-weekly and the weekly i.v. schedule for TZB. A slightly lower exposure (i.e., 25% lower) was found for the 3-weekly s.c. schedule. This important outcome confirmed the adequacy of the therapeutic dose administered in the ongoing phase 1b B-PRECISE-01 study in patients with HER2+ PI3KCA mutated advanced/metastatic BC.

Unveiling the connection: Long-chain non-coding RNAs and critical signaling pathways in breast cancer

Breast cancer is a complex and diverse condition that disrupts multiple signaling pathways essential for cell proliferation, survival, and differentiation. Recently, the significant involvement of long-chain non-coding RNAs (lncRNAs) in controlling key signaling pathways associated with breast cancer development has been discovered. This review aims to explore the interaction between lncRNAs and various pathways, including the AKT/PI3K/mTOR, Wnt/β-catenin, Notch, DNA damage response, TGF-β, Hedgehog, and NF-κB signaling pathways, to gain a comprehensive understanding of their roles in breast cancer. The AKT/PI3K/mTOR pathway regulates cell growth, survival, and metabolic function. Recent data suggests that specific lncRNAs can influence the functioning of this pathway, acting as either oncogenes or tumor suppressors. Dysregulation of this pathway is commonly observed in breast cancer cases. Moreover, breast cancer development has been associated with other pathways such as Wnt/β-catenin, Notch, TGF-β, Hedgehog, and NF-κB. Emerging studies have identified lncRNAs that modulate breast cancer's growth, progression, and metastasis by interacting with these pathways. To advance the development of innovative diagnostic tools and targeted treatment options, it is crucial to comprehend the intricate relationship between lncRNAs and vital signaling pathways in breast cancer. By fully harnessing the therapeutic potential of lncRNAs, there is a possibility of developing more effective and personalized therapy choices for breast cancer patients. Further investigation is necessary to comprehensively understand the role of lncRNAs within breast cancer signaling pathways and fully exploit their therapeutic potential.

Deciphering the Signaling Mechanisms of Osteosarcoma Tumorigenesis

Osteosarcoma (OS) is the predominant primary bone tumor in the pediatric and adolescent populations. It has high metastatic potential, with the lungs being the most common site of metastasis. In contrast to many other sarcomas, OS lacks conserved translocations or genetic mutations; instead, it has heterogeneous abnormalities, including somatic DNA copy number alteration, ploidy, chromosomal amplification, and chromosomal loss and gain. Unfortunately, clinical outcomes have not significantly improved in over 30 years. Currently, no effective molecularly targeted therapies are available for this disease. Several genomic studies showed inactivation in the tumor suppressor genes, including p53, RB, and ATRX, and hyperactivation of the tumor promoter genes, including MYC and MDM2, in OS. Alterations in the major signaling pathways, including the PI3K/AKT/mTOR, JAK/STAT, Wnt/β-catenin, NOTCH, Hedgehog/Gli, TGF-β, RTKs, RANK/RANKL, and NF-κB signaling pathways, have been identified in OS development and metastasis. Although OS treatment is currently based on surgical excision and systematic multiagent therapies, several potential targeted therapies are in development. This review focuses on the major signaling pathways of OS, and we propose a biological rationale to consider novel and targeted therapies in the future.

Calcium Homeostasis in the Development of Resistant Breast Tumors

Cancer is one of the main health problems worldwide. Only in 2020, this disease caused more than 19 million new cases and almost 10 million deaths, with breast cancer being the most diagnosed worldwide. Today, despite recent advances in breast cancer treatment, a significant percentage of patients will either not respond to therapy or will eventually experience lethal progressive disease. Recent studies highlighted the involvement of calcium in the proliferation or evasion of apoptosis in breast carcinoma cells. In this review, we provide an overview of intracellular calcium signaling and breast cancer biology. We also discuss the existing knowledge on how altered calcium homeostasis is implicated in breast cancer development, highlighting the potential utility of Ca²⁺ as a predictive and prognostic biomarker, as well as its potential for the development of new pharmacological treatments to treat the disease.

Tetraconazole interrupts mitochondrial function and intracellular calcium levels leading to apoptosis of bovine mammary epithelial cells

Tetraconazole is a type of fungicide that eliminates pathogens in plants and fruit. To date, studies have focused on the direct exposure of plants and fruits to residual tetraconazole, but no studies have been conducted on the indirect effects of tetraconzaole. Given the importance of cows as milk-producing animals and their potential exposure to pesticides via plant consumption, we analyzed the mechanism by which tetraconazole influences milk production. Here, we confirmed that tetraconazole-induced apoptosis and inhibited cell viability and proliferation by regulating the cell cycle in bovine mammary epithelial cells (MAC-T). In addition, Ca²⁺ homeostasis in mitochondria was disrupted by tetraconazole, leading to the depolarization of mitochondrial membrane potential. Consistent with the proliferation-related findings, tetraconazole downregulated AKT, ERK1/2, P38, and JNK signaling pathways and proliferation-related proteins such as CCND1 and PCNA in MAC-T cells. Meanwhile, it upregulated cleaved caspase 3, BAX, and Cytochrome c under the same conditions in MAC-T cells. Furthermore, MAC-T exposed to tetraconazole causes a failure of proper autophagy functioning. In summary, the results of this study indicated that tetraconazole exposure may lead to a failure of milk production from bovine mammary epithelial cells by disrupting calcium homeostasis and mitochondrial function.

The multifaced role and therapeutic regulation of autophagy in ovarian cancer

Ovarian cancer (OC) is one of the tumors that occurs most frequently in women. Autophagy is involved in cell homeostasis, biomolecule recycling, and survival, making it a potential target for anti-tumor drugs. It is worth noting that growing evidence reveals a close link between autophagy and OC. In the context of OC, autophagy demonstrates activity as both a tumor suppressor and a tumor promoter, depending on the context. Autophagy's exact function in OC is greatly reliant on the tumor microenvironment (TME) and other conditions, such as hypoxia, nutritional deficiency, chemotherapy, and so on. However, what can be concluded from different studies is that autophagy-related signaling pathways, especially PI3K/AKT/mTOR axis, increase in advanced stages and malignant phenotype of the disease reduces autophagy and ultimately leads to tumor progression. This study sought to present a thorough understanding of the role of autophagy-related signaling pathways in OC and existing therapies targeting these signaling pathways.

The integrative bioinformatics approaches to predict the xanthohumol as anti-breast cancer molecule: Targeting cancer cells signaling PI3K and AKT kinase pathway

Background

Breast cancer is the most common type of cancer in women, and vast research is being conducted throughout the world for the treatment of this malignancy by natural products using various computational approaches. Xanthohumol, a prenylated flavonoid, is known for its anticancer activity; however, the mechanism behind its action is still in the preliminary stage.

Methods

The current study aimed to analyze the efficacy of xanthohumol compared to the currently available anticancer drugs targeting phosphoinositide-3-kinase (PI3K), serine/threonine kinase (AKT) receptors, and human epidermal growth factor receptor 2 (HER2) for breast cancer treatment through in silico analysis.

Results

The result revealed that the target compound showed significant binding affinity to targets within the PI3K, AKT, and HER2 signaling pathways with a binding energy of -7.5, -7.9, and -7.9 kcal/mol, respectively. Further prediction studies were then made concerning this compound's absorption, distribution, metabolism, and excretion (ADME) as well as drug-likeness properties, resulting in its oral bioavailability with only a single violation of Lipinski's rule of five.

Conclusions

The finding revealed the ability of xanthohumol to bind with multiple cancer cell signaling molecules including PI3K, AKT kinase, and HER2. The current novel study opened the door to advancing research into the management and treatment of breast cancer.

XS-2, a novel potent dual PI3K/mTOR inhibitor, exhibits high in vitro and in vivo anti-breast cancer activity and low toxicity with the potential to inhibit the invasion and migration of triple-negative breast cancer

Breast cancer has become the most commonly diagnosed cancer, surpassing lung cancer, with 2.26 million new breast cancers worldwide in 2020. Hence, there is an urgent need to develop effective molecularly targeted therapeutic drugs to treat breast cancer. In this paper, we designed, synthesized and screened a novel thiophene-triazine derivative, XS-2, as a potent dual PI3K/mTOR inhibitor for the treatment of breast cancer. Also, XS-2 was found to be potentially effective against triple-negative breast cancer (TNBC) in vitro during the investigation. We evaluated the in vitro inhibitory effect of XS-2 on 10 cancer cell lines by MTT and 6 kinases to investigated its in vivo antitumor activity in MCF-7 xenograft tumor-bearing BALB/c nude mice. In addition, the in vitro/in vivo toxicity to mice was also assessed by hemolytic toxicity, H&E staining and blood biochemical analysis. In order to investigate the antitumor mechanism of XS-2, a series of experiments were carried out in vitro/in vivo animal model and molecular biological levels such as the cell cycle and the apoptosis assay, real-time PCR, western blot, docking and molecular simulations analysis, etc. What's more, wound healing assay, Transwell and Western Blot were applied to explore the ability of XS-2 to inhibit the cell invasion and migration. The results showed that XS-2 exhibited strong antitumor activity both in vitro and in vivo. The inhibitory activities of XS-2 on ten cancer cell lines were ranging from 1.07 ± 0.11 to 0.002 ± 0.001 μM, which were 1565 times better than that of the lead compound GDC-0941, inhibitory activities against PI3Kα and mTOR kinases were 291.0 and 60.8 nM, respectively. Notably, XS-2 not only showed significant in vivo antitumor activity and low toxicity, with the tumor inhibition rate of 57.0 %, but also exhibited strong inhibitory in the expression of related proteins of PI3K pathway in tumor tissues. In addition, XS-2 significantly inhibited breast cancer MCF-7 and MDA-MB-231 cells in a concentration- and time-dependent manner, and inhibited the migration and invasion ability of MDA-MB-231 and MCF-7 cells. More than that, XS-2 could inhibit the increase of the expression levels of N-cadherin and vimentin upregulated by EGF and reversed the E-cadherin expression down regulated by EGF, resulting in inhibiting EMT in MCF-7 and MDA-MB-231 cells. The results showed that XS-2 was expected to be successfully developed as a high-efficiency and low-toxicity breast cancer therapeutic drug with the potential to inhibit the invasion and migration of TNBC. This provides a new research idea for the treatment of TNBC, which is of great significance.

Molecular perspective on targeted therapy in breast cancer: a review of current status

Breast cancer is categorized at the molecular level according to the status of certain hormone and growth factor receptors, and this classification forms the basis of current diagnosis and treatment. The development of resistance to treatment and recurrence of the disease have led researchers to develop new therapies. In recent years, most of the research in the field of oncology has focused on the development of targeted therapies, which are treatment methods developed directly against molecular abnormalities. Promising advances have been made in clinical trials investigating the effect of these new treatment modalities and their combinations with existing therapeutic treatments in the treatment of breast cancer. Monoclonal antibodies, tyrosine kinase inhibitors, antibody–drug conjugates, PI3K/Akt/mTOR pathway inhibitors, cyclin-dependent kinase 4/6 inhibitors, anti-angiogenic drugs, PARP inhibitors are among the targeted therapies used in breast cancer treatment. In this review, we aim to present a molecular view of recently approved target agents used in breast cancer.

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

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

A Review of Twenty Years of Research on the Regulation of Signaling Pathways by Natural Products in Breast Cancer

Breast cancer (BC) is the second leading cause of death among women, and it has become a global health issue due to the increasing number of cases. Different treatment options, including radiotherapy, surgery, chemotherapy and anti-estrogen therapy, aromatase inhibitors, anti-angiogenesis drugs, and anthracyclines, are available for BC treatment. However, due to its high occurrence and disease progression, effective therapeutic options for metastatic BC are still lacking. Considering this scenario, there is an urgent need for an effective therapeutic strategy to meet the current challenges of BC. Natural products have been screened as anticancer agents as they are cost-effective, possess low toxicity and fewer side effects, and are considered alternative therapeutic options for BC therapy. Natural products showed anticancer activities against BC through the inhibition of angiogenesis, cell migrations, proliferations, and tumor growth; cell cycle arrest by inducing apoptosis and cell death, the downstream regulation of signaling pathways (such as Notch, NF-κB, PI3K/Akt/mTOR, MAPK/ERK, and NFAT-MDM2), and the regulation of EMT processes. Natural products also acted synergistically to overcome the drug resistance issue, thus improving their efficacy as an emerging therapeutic option for BC therapy. This review focused on the emerging roles of novel natural products and derived bioactive compounds as therapeutic agents against BC. The present review also discussed the mechanism of action through signaling pathways and the synergistic approach of natural compounds to improve their efficacy. We discussed the recent in vivo and in vitro studies for exploring the overexpression of oncogenes in the case of BC and the current status of newly discovered natural products in clinical investigations.

Functional network analysis of p85 and PI3K as potential gene targets and mechanism of oleanolic acid in overcoming breast cancer resistance to tamoxifen

Background

Tamoxifen resistance in estrogen receptor positive (ER+) breast cancer therapy increases, which is the leading cause of cancer treatment failure, as it can impair patients’ prognoses, cause cancer recurrence, metastasis, and death. Combination therapy with compounds is needed to overcome tamoxifen resistance. Oleanolic acid (OA) was known to increase tamoxifen sensitivity in tamoxifen-resistant breast cancer; however, the molecular mechanism of OA and its involvement in overcoming tamoxifen resistance remain unknown and need further investigation. This study was conducted to identify the potential gene targets and molecular mechanisms of OA in overcoming tamoxifen resistance.

Results

A bioinformatic approach for functional network analysis was used in silico by utilizing secondary data in the Gene Expression Omnibus (GEO) database and analyzing them with GEO2R to obtain data on differentially expressed genes (DEGs). The DEG data were further examined with Database for Annotation, Visualization, and Integrated Discovery (DAVID), STRING, cBioPortal website, and Cytoscape with its plugin CytoHubba. Molecular docking was performed to predict the binding properties of OA on the protein encoded by the potential gene. CD44, FGFR2, PIK3R1, and MDM2 were designated as potential target genes (PTGs), and PIK3R1 was suspected as the potential gene for OA to overcome tamoxifen resistance. Molecular docking confirms that OA can inhibit p85 activation. PIK3R1 is suggested to be the potential gene for OA in overcoming tamoxifen resistance in breast cancer therapy.

Conclusion

The predicted molecular mechanism of OA in overcoming tamoxifen resistance involves inhibiting p85 activation, leading to the inhibition of the downstream activity of the PI3K signaling pathway, causing breast cancer to respond to tamoxifen therapy once again. Results of this study need to be validated by further studies, including in vitro and in vivo.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43141-022-00341-4.

Breast Cancer Stem-Like Cells in Drug Resistance: A Review of Mechanisms and Novel Therapeutic Strategies to Overcome Drug Resistance

Breast cancer is the most frequent type of malignancy in women worldwide, and drug resistance to the available systemic therapies remains a major challenge. At the molecular level, breast cancer is heterogeneous, where the cancer-initiating stem-like cells (bCSCs) comprise a small yet distinct population of cells within the tumor microenvironment (TME) that can differentiate into cells of multiple lineages, displaying varying degrees of cellular differentiation, enhanced metastatic potential, invasiveness, and resistance to radio- and chemotherapy. Based on the expression of estrogen and progesterone hormone receptors, expression of human epidermal growth factor receptor 2 (HER2), and/or BRCA mutations, the breast cancer molecular subtypes are identified as TNBC, HER2 enriched, luminal A, and luminal B. Management of breast cancer primarily involves resection of the tumor, followed by radiotherapy, and systemic therapies including endocrine therapies for hormone-responsive breast cancers; HER2-targeted therapy for HER2-enriched breast cancers; chemotherapy and poly (ADP-ribose) polymerase inhibitors for TNBC, and the recent development of immunotherapy. However, the complex crosstalk between the malignant cells and stromal cells in the breast TME, rewiring of the many different signaling networks, and bCSC-mediated processes, all contribute to overall drug resistance in breast cancer. However, strategically targeting bCSCs to reverse chemoresistance and increase drug sensitivity is an underexplored stream in breast cancer research. The recent identification of dysregulated miRNAs/ncRNAs/mRNAs signatures in bCSCs and their crosstalk with many cellular signaling pathways has uncovered promising molecular leads to be used as potential therapeutic targets in drug-resistant situations. Moreover, therapies that can induce alternate forms of regulated cell death including ferroptosis, pyroptosis, and immunotherapy; drugs targeting bCSC metabolism; and nanoparticle therapy are the upcoming approaches to target the bCSCs overcome drug resistance. Thus, individualizing treatment strategies will eliminate the minimal residual disease, resulting in better pathological and complete response in drug-resistant scenarios. This review summarizes basic understanding of breast cancer subtypes, concept of bCSCs, molecular basis of drug resistance, dysregulated miRNAs/ncRNAs patterns in bCSCs, and future perspective of developing anticancer therapeutics to address breast cancer drug resistance.

Systematic understanding of anti-tumor mechanisms of Tamarixetin through network and experimental analyses

Tamarixetin, a flavonoid derived from Quercetin, was shown to possess anti-cancer properties in various types of cancer. However, the mechanism of action of this compound is not well understood. Observations from reverse docking and network pharmacology analysis, were validated by cell based studies to analyse the chemotherapeutic potential and elucidate the molecular mechanism of action of Tamarixetin in breast cancer. In silico analysis using reverse docking and PPI analysis clearly indicated that out of 35 proteins targeted by Tamarixetin, the top 3 hub genes, namely, AKT1, ESR1 and HSP90AA1, were upregulated in breast tumor tissues and more importantly showed strong negative correlation to breast cancer patient survival. Furthermore, the KEGG pathway analysis showed enrichment of target proteins of Tamarixetin in 33 pathways which are mainly involved in neoplastic signalling. In vitro cell-based studies demonstrated that Tamarixetin could inhibit cell proliferation, induce ROS and reduce mitochondrial membrane potential, leading to cell death. Tamarixetin induced cell cycle arrest at G2/M phase and inhibited the migration as well as the invasion of breast cancer cells. Taken together, the combination of in silico and in vitro approaches used in the present study clearly provides evidence for the chemotherapeutic potential of Tamarixetin in breast cancer.

Molecular docking analysis of mTOR protein kinase with chromatographically characterized compounds from Clerodendrum inerme L. leaves extract

The mTOR protein is known to be linked with cancer. Therefore, it is of interest to document the molecular docking analysis of mTOR protein kinase with chromatographically characterized compounds from Clerodendrum inerme L. leaves extract. The GC-MS analysis suggested that, totally 25 bioactive compounds were present in the extract of Clerodendrum inerme. Molecular docking analysis show that the bioactive compounds such as Triethoxysilanol, Piperazine dihydrochloridehydrate, 2,4(1H,3H)-Pyrimidinedione, 5-methyl and 4',7-Dihydroxyflavanone showed good glide score and glide energy within the acceptable and permissible limits of ADME properties for further consideration in drug discovery.

Plant Derived Bioactive Compounds, Their Anti-Cancer Effects and In Silico Approaches as an Alternative Target Treatment Strategy for Breast Cancer: An Updated Overview

Cancer is one of the most common malignant diseases that occur worldwide, among which breast cancer is the second leading cause of death in women. The subtypes are associated with differences in the outcome and were selected for treatments according to the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor. Triple-negative breast cancer, one of the subtypes of breast cancer, is difficult to treat and can even lead to death. If breast cancer is not treated during the initial stages, it may spread to nearby organs, a process called metastasis, through the blood or lymph system. For in vitro studies, MCF-7, MDA-MB-231, MDA-MB-468, and T47B are the most commonly used breast cancer cell lines. Clinically, chemotherapy and radiotherapy are usually expensive and can also cause side effects. To overcome these issues, medicinal plants could be the best alternative for chemotherapeutic drugs with fewer side effects and cost-effectiveness. Furthermore, the genes involved in breast cancer can be regulated and synergized with signaling molecules to suppress the proliferation of breast cancer cells. In addition, nanoparticles encapsulating (nano-encapsulation) medicinal plant extracts showed a significant reduction in the apoptotic and cytotoxic activities of breast cancer cells. This present review mainly speculates an overview of the native medicinal plant derived anti-cancerous compounds with its efficiency, types and pathways involved in breast cancer along with its genes, the mechanism of breast cancer brain metastasis, chemoresistivity and its mechanism, bioinformatics approaches which could be an effective alternative for drug discovery.

PdpaMn inhibits fatty acid synthase-mediated glycolysis by down-regulating PI3K/Akt signaling pathway in breast cancer

Novel manganese complex, PdpaMn ([(Pdpa)MnCl2]), was developed to induce apoptosis in breast cancer cells. The impact of phosphoinositide-(3)-kinase pathway onto fatty acid synthase (FASN) has an effect on cellular metabolism in breast cancer. However, reverse actions from FASN towards PI3K/Akt are still indefinable. Perhaps, loss of FASN could regulate glycolysis. Previously we established that PdpaMn inhibits FASN and involve in mitochondrial function. This study investigated the activity of PdpaMn on glycolysis and its mechanism. PdpaMn was used to suppress FASN expression in tumor. Expression of ATP and lactic acid level was measured to investigate the glycolysis variance in cells and animals. MCF-7 and 4T1 cells were treated with G28UCM, an inhibitor of FASN and PdpaMn, western blotting to detect PI3K/Akt signaling pathway. The capacity of proliferation was investigated by western blotting and immunohistochemistry. PdpaMn selectively inhibits cancer cells and tumor growth but also block FASN expression and suppresses the content of free fatty acid. Lactate dehydrogenase (LDHA) protein level was down-regulated as G28UCM and PdpaMn inhibited FASN, glucose transporter (Glut1), and pyruvate kinase (PKM2) proteins level were not affected. PI3K, p-Akt in the experimental group evidently declined compared to the control group. Proliferation was suppressed in FASN-arbitrated glycolysis. Our study supports the hypothesis that loss of FASN by PdpaMn suppressed glycolysis via down-regulating PI3K/Akt signaling pathway revealing the direct link between FASN and glycolysis. The results have paved the way to unravel the mechanisms of FASN and mitochondrial will be useful for designing novel co-targeting strategies for breast cancer.

Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer

Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.

Activation of PI3K/AKT/mTOR Pathway Causes Drug Resistance in Breast Cancer

Although chemotherapy, targeted therapy and endocrine therapy decrease rate of disease recurrence in most breast cancer patients, many patients exhibit acquired resistance. Hyperactivation of the PI3K/AKT/mTOR pathway is associated with drug resistance and cancer progression. Currently, a number of drugs targeting PI3K/AKT/mTOR are being investigated in clinical trials by combining them with standard therapies to overcome acquired resistance in breast cancer. In this review, we summarize the critical role of the PI3K/AKT/mTOR pathway in drug resistance, the development of PI3K/AKT/mTOR inhibitors, and strategies to overcome acquired resistance to standard therapies in breast cancer.

The Breast Cancer Stem Cells Traits and Drug Resistance

Drug resistance is a major challenge in breast cancer (BC) treatment at present. Accumulating studies indicate that breast cancer stem cells (BCSCs) are responsible for the BC drugs resistance, causing relapse and metastasis in BC patients. Thus, BCSCs elimination could reverse drug resistance and improve drug efficacy to benefit BC patients. Consequently, mastering the knowledge on the proliferation, resistance mechanisms, and separation of BCSCs in BC therapy is extremely helpful for BCSCs-targeted therapeutic strategies. Herein, we summarize the principal BCSCs surface markers and signaling pathways, and list the BCSCs-related drug resistance mechanisms in chemotherapy (CT), endocrine therapy (ET), and targeted therapy (TT), and display therapeutic strategies for targeting BCSCs to reverse drug resistance in BC. Even more importantly, more attention should be paid to studies on BCSC-targeted strategies to overcome the drug resistant dilemma of clinical therapies in the future.

Hispidulin: A novel natural compound with therapeutic potential against human cancers

Cancer is one of the most devastating disease and leading cause of death worldwide. The conventional anticancer drugs are monotarget, toxic, expensive and suffer from drug resistance. Development of multi-targeted drugs from natural products has emerged as a new paradigm to overcome aforementioned conventionally encountered obstacles. Hispidulin (HIS), is a biologically active natural flavone with versatile biological and pharmacological activities. The anticancer, antimutagenic, antioxidative and anti-inflammatory properties of HIS have been reported. The aim of this review is to summarize the findings of several studies over the last few decades on the anticancer activity of HIS published in various databases including PubMed, Google Scholar, and Scopus. HIS has been shown to reduce the growth of cancer cells by inducing apoptosis, arresting cell cycle, inhibiting angiogenesis, invasion and metastasis via modulating multiple signaling pathways implicated in cancer initiation and progression. Multitargeted anticancer activity of HIS remains the strongest point for developing it into potential anticancer drug. We also highlighted the natural sources, anticancer mechanism, cellular targets, and chemo-sensitizing potential of HIS. This review will provide bases for design and conduct of further pre-clinical and clinical trials to develop HIS into a lead structure for future anticancer therapy.

Long Noncoding RNA ADAMTS9-AS2 Inhibits the Proliferation, Migration, and Invasion in Bladder Tumor Cells

BACKGROUND

Bladder tumor is the fifth most prevalent tumor in men, yet its pathogenesis remains to be fully identified. Albeit a host of long noncoding RNAs (lncRNA) are emerging as new players involved in bladder tumor, the functions of many lncRNAs are still enigmatic. Reports on the deluge of studies on lncRNA ADAMTS9-AS2 have been convincingly associated with various tumors, but without mention of its roles in bladder tumor. Therefore, the roles of ADAMTS9-AS2 in bladder tumor cells were explored in our study.

MATERIALS AND METHODS

Quantitative real-time PCR assays and bioinformatic tools were applied in bladder tumor cells to identify the ADAMTS9-AS2 and ADAMTS9 expression. Western blot assays were performed to obtain the protein levels of bladder tumor related key molecules. CCK8, clonogenic assay, scratch wound healing, and transwell assays were separately applied to identify the functional roles of ADAMTS9-AS2 on proliferation, migration, and invasion in bladder tumor cells.

RESULTS

First, ADAMTS9-AS2 downregulation in bladder tumor cells was identified. Overexpression and knockdown experiments showed that ADAMTS9-AS2 expression was positively related to ADAMTS9, which is in accordance with the results from GEO database. Second, ADAMTS9-AS2 contributed to the inhibition of proliferation, migration, and invasion in bladder tumor cells. Third, ADAMTS9-AS2 was linked with PI3K/AKT/mTOR pathway related-molecules, several key autophagy, and apoptotic proteins.

CONCLUSION

Conjointly, our findings suggested that ADAMTS9-AS2 might function as a tumor suppressor to restrain the proliferation, migration, and invasion in bladder tumor cells. The potential mechanism of ADAMTS9-AS2 related to PI3K/AKT/mTOR signal pathway was further identified. Of note, we found that ADAMTS9-AS2 has a significant effect on several key autophagy and apoptotic proteins. Therefore, these observations will provide supportive evidence to ADAMTS9-AS2 as a potential biomarker in patients with bladder tumor.

circNFATC3 sponges miR-548I acts as a ceRNA to protect NFATC3 itself and suppressed hepatocellular carcinoma progression

Circular RNAs (circRNA) have been reported as regulators involved in hepatocellular carcinoma (HCC), but their mechanism of activity remains unknown. This study performed quantitative reverse-transcription polymerase chain reaction to determine if circNFATC3 was downregulated in 46 paired HCC tissues and cell lines. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, apoptotic, and transwell assay proved that circNFATC3 can inhibit hepatoma cell proliferation, apoptosis, and migration/invasion in vitro. Mouse xenograft assay demonstrated that circNFATC3 suppressed tumor size and weight and reduced lung metastasis in vivo, and vice versa. The RNA-seq results showed that NFATC3 itself was the most significantly differentially expressed gene when circNFATC3 was manipulated, and bioinformatics and luciferase reporter assays verified circNFATC3 regulated the expression of NFATC3 by interacting with the hsa-miR-548I. Additionally, it was also indicated that the level of NFATC3 was downregulated in HCC patients also and was significantly correlated with the staging and prognosis of HCC. Moreover, both circNFATC3 and NFATC3 were shown to inhibit the phosphorylation of JNK, c-Jun, AKT, and mTOR signaling pathways. Overall, the circNFATC3 can sponge miR-548I to protect NFATC3 itself, then it regulates hepatoma cell function via the JNK, c-Jun, AKT, and mTOR signaling pathways, and the circNFATC3 can be a tumor-repressor on HCC.

Using Phosphatidylinositol Phosphorylation as Markers for Hyperglycemic Related Breast Cancer

Studies have suggested that type 2 diabetes (T2D) is associated with a higher incidence of breast cancer and related mortality rates. T2D postmenopausal women have an ~20% increased chance of developing breast cancer, and women with T2D and breast cancer have a 50% increase in mortality compared to breast cancer patients without diabetes. This correlation has been attributed to the general activation of insulin receptor signaling, glucose metabolism, phosphatidylinositol (PI) kinases, and growth pathways. Furthermore, the presence of breast cancer specific PI kinase and/or phosphatase mutations enhance metastatic breast cancer phenotypes. We hypothesized that each of the breast cancer subtypes may have characteristic PI phosphorylation profiles that are changed in T2D conditions. Therefore, we sought to characterize the PI phosphorylation when equilibrated in normal glycemic versus hyperglycemic serum conditions. Our results suggest that hyperglycemia leads to: 1) A reduction in PI3P and PIP3, with increased PI4P that is later converted to PI(3,4)P2 at the cell surface in hormone receptor positive breast cancer; 2) a reduction in PI3P and PI4P with increased PIP3 surface expression in human epidermal growth factor receptor 2-positive (HER2+) breast cancer; and 3) an increase in di- and tri-phosphorylated PIs due to turnover of PI3P in triple negative breast cancer. This study begins to describe some of the crucial changes in PIs that play a role in T2D related breast cancer incidence and metastasis.

Derlin-1 functions as a growth promoter in breast cancer

Breast cancer is one of the most common malignant tumors in women. Derlin-1 has been found to be overexpressed in several human cancers in addition to playing an important role in tumor processes; however, the expression patterns and functions of Derlin-1 in human breast cancer are not fully understood. In this study, we found that Derlin-1 overexpression was higher in breast cancer compared to normal samples through TCGA and GTEx database analyses. Kaplan-Meier plotter analysis showed that Derlin-1 was a predicting factor for patient prognosis. Derlin-1 expression was significantly up-regulated in breast cancer tissues (18/30, 60.00%) compared to corresponding paracancerous tissue (9/30, 30.00%, p < 0.05) as detected by immunohistochemistry, and the expression of Derlin-1 was correlated to pathological grading. siRNA interference of Derlin-1 inhibited cell proliferation, which is associated with the promotion of apoptosis and migration. Derlin-1 knockdown suppressed the protein levels of p-AKT and Cyclin D1 while up-regulating Caspase3 and Bax. GEPIA database analysis showed that MTDH and ATAD2 were downstream target genes, and the expression of MTDH and was suppressed in Derlin-1 knockdown cells. Taken together, our results demonstrated ATAD2 that Derlin-1 is overexpressed in breast cancer and promoted a malignant phenotype through the AKT signaling pathway.

Predicting Radiation Resistance in Breast Cancer with Expression Status of Phosphorylated S6K1

Emerging evidence suggests that the mammalian target of rapamcyin (mTOR) pathway is associated with radio-resistance in cancer treatment. We hypothesised that phosphorylated ribosomal S6 kinase 1 (p-S6K1), a major downstream regulator of the mTOR pathway, may play a role in predicting radio-resistance. Therefore, we evaluated the association of p-S6K1 expression with radio-resistance in breast cancer cell lines and patients. During median follow-up of 33 (range, 0.1-111) months for 1770 primary breast cancer patients who underwent surgery, patients expressing p-S6K1 showed worse 10-year loco-regional recurrence-free survival (LRFS) compared to that of p-S6K1-negative patients after radiotherapy (93.4% vs. 97.7%, p = 0.015). Multivariate analysis revealed p-S6K1 expression as a predictor of radio-resistance (hazard ratio 7.9, 95% confidence interval 1.1-58.5, p = 0.04). In vitro, CD44^high/CD24^low MCF7 cells with a radioresistant phenotype expressed higher levels of p-S6K1 than control MCF7 cells. Furthermore, the combination of radiation with treatment of everolimus, an mTOR-S6K1 pathway inhibitor, sensitised CD44^high/CD24^low MCF7 cells to a greater extent than MCF7 cells. This study provides in vivo and in vitro evidence for p-S6K1 expression status as an important marker for predicting the resistance to radiotherapy and as a possible target for radio-sensitization in breast cancer patients.

Expression of Bioinformatically Candidate miRNAs including, miR-576-5p, miR-501-3p and miR-3143, Targeting PI3K Pathway in Triple-Negative Breast Cancer

Background

Triple-negative breast cancer (TNBC) is an invasive and lethal form of breast cancer. PI3K pathway, which often activated in TNBC patients, can be a target of miRNAs. The purpose of this study was bioinformatic prediction of miRNAs targeting the key genes of this pathway and evaluation of the expression of them and their targets in TNBC.

Materials and Methods

We predicted miRNAs targeting PIK3CA and AKT1 genes using bioinformatics tools. Extraction of total RNA, synthesis of cDNA and quantitative real-time polymerase chain reaction were performed from 18 TNBC samples and normal adjacent tissues and cell lines.

Results

Our results demonstrated that miR-576-5p, miR-501-3p and miR-3143 were predicted to target PIK3CA, AKT1 and both of these mRNAs, respectively and were down-regulated while their target mRNAs were up-regulated in clinical samples and cell lines. The analysis of the receiver operating characteristic curve was done for the evaluation of the diagnostic value of predicted miRNAs in TNBC patients.

Conclusion

The findings of our study demonstrated the reverse correlation between miRNAs and their target genes and therefore the possibility of these miRNAs to be proposed as new candidates for TNBC targeted therapies.

Bag-1 Silence Sensitizes Non-Small Cell Lung Cancer Cells To Cisplatin Through Multiple Gene Pathways

Purpose

B-cell lymphoma-2 (Bcl-2) associated athanogene 1 (Bag-1) is a multifunctional protein, and Bag -1 overexpression is associated with progression, metastasis, and drug resistance in lung cancer. This study assessed the effects of Bag-1 siRNA on sensitization of cisplatin on non-small cell lung cancer (NSCLC) cells.

Material and methods

NSCLC A549 cell line was transfected with Bag-1 or negative control siRNA and then treated with cisplatin for cell viability, CCK-8, LDH, and flow cytometry assays. The Ca²⁺ levels were analyzed using Fluo-3/AM fluorescence staining, and the protein levels were assessed using Western blot analysis.

Results

Bag-1 siRNA significantly knocked down Bag-1 expression and inhibited cell invasion versus the negative control siRNA, while Bag-1 silence sensitized cisplatin to induce A549 cells to apoptosis by induction of cell cycle G1 arrest. At protein level, Bag-1 silence reduced the expression ratio of Bcl-2 to Bcl-2 associated X protein (Bax), downregulated activity of the PI3K/AKT and mitogen-activated protein kinase (MAPK) pathways, and potently upregulated the calcium signaling-mediated pathway.

Conclusion

This study demonstrated that Bag-1 silencing sensitized A549 to cisplatin to enhance A549 cell apoptosis by modified multiple gene pathways. Further study will evaluate the usefulness of Bag-1 siRNA as a potential targeting therapy for NSCLC.

CapG promotes resistance to paclitaxel in breast cancer through transactivation of PIK3R1/P50

Background: Chemotherapy resistance is a major problem in breast cancer treatment and a leading cause of mortality in breast cancer patients. Biomarkers for chemotherapy resistance is under investigation.

Methods: Paclitaxel resistant cells were established and subjected to RNA sequencing. Analysis combined with two additional RNA-seq datasets was conducted. CapG expression in patients with adjuvant chemotherapy was studied in breast cancer resection specimens using IHC and related to pathological response and disease-free survival. Paclitaxel resistance was assessed by half-maximal inhibitory concentrations (IC50) and a mouse xenograft model.

Results: Increased expression of actin-binding protein CapG strongly correlated with the resistance to paclitaxel chemotherapy and decreased probability to achieve pathological complete response in breast cancer patients. Overexpressing CapG significantly enhanced paclitaxel resistance in breast cancer cells and xenograft tumors. High CapG level also significantly correlated with shorter relapse-free survival as well as hyper-activation of PI3K/Akt signaling in breast cancer patients. Mechanistically, CapG enhanced PIK3R1 expression which led to increased PI3K/Akt activation. Unexpectedly, CapG was found to bind to the variant-specific promoter of PIK3R1/P50 and directly enhance its transcription. We also identified p300/CBP as a transcriptional coregulator of CapG, which is recruited to PIK3R1 promoter through interaction with CapG, thereby increasing PIK3R1/P50 transcription by enhancing histone H3K27 acetylation. Consistently, inhibiting p300/CBP substantially decreased CapG-dependent upregulation of PIK3R1/P50 and subsequent PI3K/Akt activation, resulting in increased sensitivity to paclitaxel treatment in breast cancer cells.

Conclusion: High CapG levels may predict poor paclitaxel response in breast cancer patients. Targeting CapG-mediated hyperactivation of PI3K/Akt pathway may mitigate resistance to chemotherapy in breast cancer.

Identification of core genes and clinical roles in pregnancy-associated breast cancer based on integrated analysis of different microarray profile datasets

More women are delaying child-birth. Thus, the diagnosis of pregnancy-associated breast cancer (PABC) will continue to increase. The aim of this study was to identify core candidate genes of PABC, and the relevance of the genes on the prognosis of PABC. GSE31192 and GSE53031 microarray profile datasets were downloaded from the Gene Expression Omnibus database and differentially expressed genes were analyzed using the R package and GEO2R tool. Then, Gene Ontology and Kyoto Encyclopedia of Gene and Genome pathway enrichment analyses were performed using the Database for Annotation, Visualization, and Integrated Discovery. Moreover, the Search Tool for the Retrieval of Interacting Genes and the Molecular Complex Detection Cytoscape software plug-in were utilized to visualize protein–protein interactions and to screen candidate genes. A total of 239 DEGs were identified in PABC, including 101 up-regulated genes mainly enriched in fatty acid activation and the fibroblast growth factor signaling pathway, while 138 down-regulated genes particularly involved in activation of DNA fragmentation factor and apoptosis-induced DNA fragmentation. Fourteen hub genes with a high degree of connectivity were selected, including CREB1, ARF3, UBA5, SIAH1, KLHL3, HECTD1, MMP9, TRIM69, MEX3C, ASB6, UBE2Q2, FBXO22, EIF4A3, and PXN. Overall survival (OS) analysis of core candidate genes was performed using the Gene Expression Profiling Interactive Analysis and UALCAN websites. High ASB6 expression was associated with worse OS of PABC patients. Molecular subtypes and menopause status were also associated with worse OS for PABC patients. In conclusion, ASB6 could be a potential predictor and therapeutic target in patient with PABC.

Suppression of epidermal growth factor receptor-mediated β-catenin nuclear accumulation enhances the anti-tumor activity of phosphoinositide 3-kinase inhibitor in breast cancer

Phosphoinositide 3-kinase (PI3K) signaling is frequently deregulated in breast cancer and plays a critical role in tumor progression. However, resistance to PI3K inhibitors in breast cancer has emerged, which is due to the enhanced β-catenin nuclear accumulation. Until now, the mechanisms underlying PI3K inhibition-induced β-catenin nuclear accumulation remains largely unknown. In the present study, we found inhibition of PI3K with LY294002 promoted β-catenin nuclear accumulation in MCF-7 and MDA-MB-231 breast cancer cells. Combining PI3K inhibitor LY294002 with XAV-939, an inhibitor against β-catenin nuclear accumulation, produced an additive anti-proliferation effect against breast cancer cells. Subsequent experiments suggested β-catenin nuclear accumulation induced by PI3K inhibition depended on the feedback activation of epidermal growth factor receptor (EGFR) signaling pathway in breast cancer cells. Inhibition of EGFR phosphorylation with Gefitinib enhanced anti-proliferation effect of PI3K inhibitor LY294002 in MCF-7 and MDA-MB-231 cells. Taken together, our findings may elucidate a possible mechanism explaining the poor outcome of PI3K inhibitors in breast cancer treatment.

An In silico Approach to Identify High Affinity Small Molecule Targeting m-TOR Inhibitors for the Clinical Treatment of Breast Cancer

Breast cancer is the most frequent malignancy among women. It is a heterogeneous disease with different subtypes defined by its hormone receptor. A hormone receptor is mainly concerned with the progression of the PI3K/AKT/mTOR pathway which is often dysregulated in breast cancer. This is a major signaling pathway that controls the activities such as cell growth, cell division, and cell proliferation. The present study aims to suppress mTOR protein by its various inhibitors and to select one with the highest binding affinity to the receptor protein. Out of 40 inhibitors of mTOR against breast cancer, SF1126 was identified to have the best docking score of -8.705, using Schrodinger Suite which was further subjected for high throughput screening to obtain best similar compound using Lipinski’s filters. The compound obtained after virtual screening, ID: ZINC85569445 is seen to have the highest affinity with the target protein mTOR. The same result based on the binding free energy analysis using MM-GBSA showed that the compound ZINC85569445 to have the the highest binding free energy. The next study of interaction between the ligand and receptor protein with the pharmacophore mapping showed the best conjugates, and the ZINC85569445 can be further studied for future benefits of treatment of breast cancer.

Novel naphthalene-enoates: Design and anticancer activity through regulation cell autophagy

Eleven dihydroxy-2-(1-hydroxy-4-methylpent-3-enyl)naphthalene derivatives as anticancer agents through regulating cell autophagy were designed and synthesized. The anticancer activity results indicated that most compounds manifested obvious un-toxic effect on GES-1 and L-02 with IC₅₀ from 0.58 to 1.41 mM. Among them, (S,Z)-1-(5,8-dihydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-4-methylpent-3-enyl 4-(3,4- dihydroisoquinolin-2(1 H)-yl)-4-oxobut-2-enoate (compound 4i) could induce cancer cells apoptosis. Further experiments showed that autophagy played an important role in the pro-apoptotic effect of this compound. Preliminary mechanism indicated that this compound could inhibit phosphoinositide 3-kinase/protein kinase B and the mammalian target of rapamycin (PI3K/AKT/mTOR) pathway by mediating apoptosis in an autophagy-dependent manner.

The relation between PI3K/AKT signalling pathway and cancer

Phosphatidylinositol 3-kinases (PI3Ks) are crucial coordinators of intracellular signalling in response to the extracellular stimulators. Hyperactivation of PI3K signalling cascades is one among the most ordinary events in human cancers. Focusing on the PI3K pathway remains both a chance and a challenge for cancer therapy. The high recurrence of phosphoinositide 3-kinase (PI3K) pathway adjustments in cancer has led to a surge in the progression of PI3K inhibitors. Recent developments incorporate a re-assessment of the oncogenic mechanisms behind PI3K pathway modifications. Receptor tyrosine kinases upstream of PI3K, the p110a catalytic fractional unit of PI3K, the downstream kinase, AKT, and therefore the negative regulator, PTEN, are all often altered in cancer. In this review, we consider about the phosphoinositide 3-kinases family and mechanisms of PI3K-Akt stimulation in cancer.

Bag-1 silencing enhanced chemotherapeutic drug-induced apoptosis in MCF-7 breast cancer cells affecting PI3K/Akt/mTOR and MAPK signaling pathways

The multifunctional anti-apoptotic Bag-1 protein has important roles in apoptosis, proteasome-mediated degradation, transcriptional regulation, and intracellular signaling. Bag-1 promotes cell survival and proliferation, and is overexpressed in breast cancer. Therefore, Bag-1-targeted therapy might be a promising strategy to treat breast cancer. However, the effects of Bag-1 silencing in combination with conventional chemotherapeutic drugs on cell viability and major signaling pathways have not yet been fully investigated in breast cancer cells. In this study, we investigated the cytotoxic effects of Bag-1 silencing, alone and in combination with cisplatin or paclitaxel treatment, in MCF-7 breast cancer cells. Bag-1 knockdown by shRNA or siRNA transfection sensitized MCF-7 cells to apoptosis induced by cisplatin or paclitaxel. Combination of Bag-1 silencing and drug treatment more potently downregulated the pro-survival PI3K/Akt/mTOR and p44/42 mitogen activated protein kinase (MAPK) pathways, and more potently upregulated the stress-activated p38 and SAPK/JNK MAPK pathways. Bag-1-silenced drug-treated cells had also highly reduced proliferative capacity, downregulated cyclin-cyclin dependent kinase complexes and upregulated tumor suppressors p21 and Rb. These results overall indicated that Bag-1 silencing enhanced cisplatin- or paclitaxel-induced cytotoxicity through multiple pathways. In conclusion, Bag-1 targeted therapy might enhance the therapeutic potential of conventional anti-cancer drugs in the treatment of breast cancer.

An integrated approach of bioinformatic prediction and in vitro analysis identified that miR-34a targets MET and AXL in triple-negative breast cancer

BACKGROUND

Breast cancer is the most prevalent cancer among women, and AXL and MET are the key genes in the PI3K/AKT/mTOR pathway as critical elements in proliferation and invasion of cancer cells. MicroRNAs (miRNAs) are small non-coding RNAs regulating the expression of genes.

METHODS

Bioinformatic approaches were used to find a miRNA that simultaneously targets both AXL and MET 3'-UTRs. The expression of target miRNA was evaluated in triple-negative (MDA-MB-231) and HER2-overexpressing (SK-BR-3) breast cancer cell lines as well as normal breast cells, MCF-10A, using quantitative real-time PCR. Then, the miRNA was overexpressed in normal and cancer cell lines using a lentiviral vector system. Afterwards, effects of overexpressed miRNA on the expression of AXL and MET genes were evaluated using quantitative real-time PCR.

RESULTS

By applying bioinformatic software and programs, miRNAs that target the 3'-UTR of both AXL and MET mRNAs were determined, and according to the scores, miR-34a was selected for further analyses. The expression level of miR-34a in MDA-MB-231 and SK-BR-3 was lower than that of MCF-10A. Furthermore, AXL and MET expression in SK-BR-3 and MDA-MB-231 was lower and higher, respectively, than that of MCF-10A. After miR-34a overexpression, MET and AXL were downregulated in MDA-MB-231. In addition, MET was downregulated in SK-BR-3, while AXL was upregulated in this cell line.

CONCLUSIONS

These findings may indicate that miR-34a is an oncogenic miRNA, downregulated in the distinct breast cancer subtypes. It also targets MET and AXL 3'-UTRs in triple-negative breast cancer. Therefore, it can be considered as a therapeutic target in this type of breast cancer.

Cancer stem cell in breast cancer therapeutic resistance

Development of therapeutic resistance and metastasis is a major challenge with current breast cancer (BC) therapy. Mounting evidence suggests that a subpopulation of cancer stem cells (CSCs) contribute to the cancer therapeutic resistance and metastasis, leading to the recurrence and death in patients. Breast cancer stem cells (BCSCs) are not only a consequence of mutations that overactivate the self-renewal ability of normal stem cells or committed progenitors but also a result of the de-differentiation of cancer cells induced by somatic mutations or microenvironmental components under treatment. Eradication of BCSCs may bring hope and relief to patients whose lives are threatened by recurrent BCs. Therefore, a better understanding of the generation, regulatory mechanisms, and identification of CSCs in BC therapeutic resistance and metastasis will be imperative for developing BCSC-targeted strategies. Here we summarize the latest studies about cell surface markers and signalling pathways that sustain the stemness of BCSC and discuss the associations of mechanisms behind these traits with phenotype and behavior changes in BCSCs. More importantly, their implications for future study are also evaluated and potential BCSC-targeted strategies are proposed to break through the limitation of current therapies.

Benzimidazoisoquinoline derivatives inhibit glioblastoma cell proliferation through down-regulating Raf/MEK/ERK and PI3K/AKT pathways

Background

Recent studies showed that benzimidazoleisoquinolinone derivatives exhibit anticancer activity against human cancer cell lines. The aim of this study is to evaluate the anti-tumor effects and mechanisms of benzimidazoleisoquinolinones in isocitrate dehydrogenase-wildtype subtype of human glioblastoma (GBM) cells.

Methods

Human U87 and LN229 cell lines were used to perform the experiments. MTT was applied to screen the effective small molecular inhibitors suppressing growth of GBM cells. Colony formation and BrdU staining assays were performed to assess the inhibition effect of compound-1H on the proliferation of GBM cells. The cell cycle and apoptosis were measured by flow cytometry and western blot to analyze the changes of the relative protein expressions and their signal pathways.

Results

Compound-1H could suppress GBM cells in a time- and dose-dependent manner. Treatment of compound-1H could arrest cell cycle in S phase through up-regulating P21 and P53, and down-regulating cyclin A and E in a dose-dependent manner. Compound-1H also induced mitochondrial-dependent apoptosis by increasing Bax, cleaved caspase-3, cleaved caspase-9 and poly ADP-ribose polymerase expression, and decreasing Bcl-2 expression. Moreover, phosphorylated (p)-AKT and p-ERK levels relating to cell proliferation were dramatically decreased in U87 and LN229 cells.

Conclusions

Our results suggest that it is the first time to report the compound-1H with benzimidazoleisoquinolinone core playing antitumor activity in human glioblastoma cells by inhibiting Raf/MEK/ERK and PI3K/AKT signaling pathways, and it could be as a lead compound for the further development of targeted glioblastoma cancer therapy.

Global expression profiling and pathway analysis of mouse mammary tumor reveals strain and stage specific dysregulated pathways in breast cancer progression

It is believed that the alteration of tissue microenvironment would affect cancer initiation and progression. However, little is known in terms of the underlying molecular mechanisms that would affect the initiation and progression of breast cancer. In the present study, we use two murine mammary tumor models with different speeds of tumor initiation and progression for whole genome expression profiling to reveal the involved genes and signaling pathways. The pathways regulating PI3K-Akt signaling and Ras signaling were activated in Fvb mice and promoted tumor progression. Contrastingly, the pathways regulating apoptosis and cellular senescence were activated in Fvb.B6 mice and suppressed tumor progression. We identified distinct patterns of oncogenic pathways activation at different stages of breast cancer, and uncovered five oncogenic pathways that were activated in both human and mouse breast cancers. The genes and pathways discovered in our study would be useful information for other researchers and drug development.

Extract from Astragalus membranaceus inhibit breast cancer cells proliferation via PI3K/AKT/mTOR signaling pathway

Background

Astragalus membranaceus (AM) is a commonly used herb in traditional Chinese medicine (TCM), which has been used as an essential tonic to treat various diseases for more than 2000 years. In this study, we aimed to investigate the biological effects of extract from AM on breast cancer cell and its mechanism.

Methods

To prepare the extract, dried AM were ground and extracted with water extraction-ethanol supernatant method. Then the main isoflavones in the extract was detect by HPLC analysis. Furthermore, the anti-proliferative activity of AM extract was examined by MTT assay and morphological observation. Cell apoptosis was evaluated with flow cytometric analysis. The expressions of total and phosphorylated PI3K, GS3Kβ, Akt and mTOR were determined by western blot analysis.

Results

HPLC analysis demonstrated that AM extract contained with four kinds of isoflavones, campanulin, ononin, calycosin and formononetin. The MTT test and morphological observation indicated that cells proliferation of MCF-7, SK-BR-3 and MDA-MB-231were inhibited by AM extract in a dose dependent manner. Furthermore, flow cytometric analysis displayed that after treated with 25 μg/ml and 50 μg/ml AM extract, apoptosis of breast cancer cells was significantly increased as compared with DMSO and blank control group (all p < 0.05). Western blot analysis found that the level of p-PI3K, p-GS3Kβ, p-Akt, and p-mTOR were significantly decreased, but the level of total-mTOR was observably increased as compared with DMSO control group.

Conclusions

Taken together, the inhibited cell proliferation and induced cell apoptosis effect of AM extract via PI3K/AKT/mTOR pathway confirmed the anti-tumor potential of AM. Therefore, our findings provide a new insight into anti-cancer effect of AM extract as a promising agent in breast cancer treatment.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2148-2) contains supplementary material, which is available to authorized users.

Association of urinary and plasma DNA in early breast cancer patients and its links to disease relapse

PURPOSE

Identifying patients who are at risk of relapse is a key challenge of primary breast cancer. The current study investigates the utility of urinary DNA in breast cancer management and as a predictor of relapse. This work also compares the sensitivity of plasma DNA with urinary DNA.

METHODS

Blood plasma and urine specimens were collected concurrently from 200 breast cancer patients receiving neoadjuvant chemotherapy. Comparison of both plasma and urinary DNA was performed at baseline to determine assay significance. Serial measurements of urinary DNA were conducted to gauge DNA variations after surgery. Correlations to disease relapse were performed to affirm the clinical utility of urinary DNA.

RESULTS

Molecular analysis showed patients were successfully identified with mutant PIK3CA using urinary DNA. A strong correlation was affirmed from urinary and plasma DNA at baseline with the correlation coefficient r = 0.859. We analyzed post-surgery measurements of urinary DNA for disease-relapse predictions. In subsequent serial followup of urinary DNA samples, we confirmed increased sensitivity in predicting relapse of these patients. The hazard ratio determined at the 9-month was 1.51 that identified patients at greater risk of disease relapse.

CONCLUSION

Urinary DNA offers a unique opportunity to glimpse upon dynamic changes in early breast cancer. Our results demonstrated good correlation to plasma DNA and post monitoring of cancer patients to identify individuals susceptible to a high risk of relapse. This potentially allows for early intervention such as adjuvant chemotherapy to be administered to better manage these patients.

PI3K inhibition to overcome endocrine resistance in breast cancer

INTRODUCTION

Activation of the phosphatidylinositol-3 kinase (PI3K) pathway is a critical step in oncogenesis and plays a role in the development of treatment resistance for both estrogen receptor (ER) positive and human epidermal growth factor receptor 2 (HER2) positive breast cancers. Hence, there have been efforts to therapeutically inhibit this pathway.

AREAS COVERED

Several inhibitors of PI3K are now progressing through clinical trials with varying degrees of efficacy and toxicity to date. Numerous unresolved questions remain concerning the optimal isoform selectivity of PI3K inhibitors and use of predictive biomarkers. This review examines the most important PI3K inhibitors in ER positive breast cancer to date, with a particular focus on their role in overcoming endocrine therapy resistance and the possible use of PIK3CA mutations as a predictive biomarker.

EXPERT OPINION

We discuss some of the emerging challenges and questions encountered during the development of PI3K inhibitors from preclinical to phase III studies, including other novel biomarkers and future combinations to overcome endocrine resistance.

A randomized adaptive phase II/III study of buparlisib, a pan-class I PI3K inhibitor, combined with paclitaxel for the treatment of HER2- advanced breast cancer (BELLE-4)

Background

Phosphatidylinositol 3-kinase (PI3K) pathway activation in preclinical models of breast cancer is associated with tumor growth and resistance to anticancer therapies, including paclitaxel. Effects of the pan-Class I PI3K inhibitor buparlisib (BKM120) appear synergistic with paclitaxel in preclinical and clinical models.

Patients and methods

BELLE-4 was a 1:1 randomized, double-blind, placebo-controlled, adaptive phase II/III study investigating the combination of buparlisib or placebo with paclitaxel in women with human epidermal growth factor receptor 2-negative locally advanced or metastatic breast cancer with no prior chemotherapy for advanced disease. Patients were stratified by PI3K pathway activation and hormone receptor status. The primary endpoint was progression-free survival (PFS) in the full and PI3K pathway-activated populations. An adaptive interim analysis was planned following the phase II part of the study, after ≥125 PFS events had occurred in the full population, to decide whether the study would enter phase III (in the full or PI3K pathway-activated population) or be stopped for futility.

Results

As of August 2014, 416 patients were randomized to receive buparlisib (207) or placebo (209) with paclitaxel. At adaptive interim analysis, there was no improvement in PFS with buparlisib versus placebo in the full (median PFS 8.0 versus 9.2 months, hazard ratio [HR] 1.18), or PI3K pathway-activated population (median PFS 9.1 versus 9.2 months, HR 1.17). The study met protocol-specified criteria for futility in both populations, and phase III was not initiated. Median duration of study treatment exposure was 3.5 months in the buparlisib arm versus 4.6 months in the placebo arm. The most frequent adverse events with buparlisib plus paclitaxel (≥40% of patients) were diarrhea, alopecia, rash, nausea, and hyperglycemia.

Conclusions

Addition of buparlisib to paclitaxel did not improve PFS in the full or PI3K pathway-activated study population. Consequently, the trial was stopped for futility at the end of phase II.

Stachydrine hydrochloride inhibits proliferation and induces apoptosis of breast cancer cells via inhibition of Akt and ERK pathways

Although a series of efficient Akt and ERK inhibitors have been developed to target breast cancer cells, drug resistance can emerge after long-term treatment. Therefore, it is essential to uncover alternative drugs for inhibiting survival pathways in breast cancer cells. Stachydrine hydrochloride, a well-known bioactive ingredients extracted from HerbaLeonuri, has proven to be very efficient for the treatment of various diseases such as prostate cancer. However, whether stachydrine hydrochloride can exert similar prophylactic and therapeutic effects against breast cancer, and the probable underlying molecular mechanism remain unknown. In the present work, the effects of stachydrine hydrochloride on human breast cancer cell lines (T47D and MCF-7) were evaluated. Our results showed that Stachydrine hydrochloride inhibits cell proliferation and induces primary apoptosis and ROS production in T47D and MCF-7 cells in time- and dose-dependent manner. Mechanistically, Stachydrine hydrochloride treatment induced caspase-3 activation and decreased the expression of the anti-apoptotic protein Bcl-2. Moreimportantly, Stachydrine hydrochloride simultaneously inhibited the phosphorylation of Akt and ERK proteins. Overall, our data indicated that Stachydrine hydrochloride induces apoptosis in MCF-7 and T47D cells and exerts inhibitory effects on proliferation by concurrently suppressing Akt and ERK survival signals, suggesting its potential efficiency in treatment of breast cancer.

IFITM1 suppression blocks proliferation and invasion of aromatase inhibitor-resistant breast cancer in vivo by JAK/STAT-mediated induction of p21

Interferon induced transmembrane protein 1 (IFITM1) belongs to a family of interferon stimulated genes (ISGs) that is associated with tumor progression and DNA damage resistance; however, its role in endocrine resistance is not known. Here, we correlate IFITM1 expression with clinical stage and poor response to endocrine therapy in a tissue microarray consisting of 94 estrogen receptor (ER)-positive breast tumors. IFITM1 overexpression is confirmed in the AI-resistant MCF-7:5C cell line and not found in AI-sensitive MCF-7 cells. In this study, the orthotopic (mammary fat pad) and mouse mammary intraductal (MIND) models of breast cancer are used to assess tumor growth and invasion in vivo. Lentivirus-mediated shRNA knockdown of IFITM1 in AI-resistant MCF-7:5C cells diminished tumor growth and invasion and induced cell death, whereas overexpression of IFITM1 in wild-type MCF-7 cells promoted estrogen-independent growth and enhanced their aggressive phenotype. Mechanistic studies indicated that loss of IFITM1 in MCF-7:5C cells markedly increased p21 transcription, expression and nuclear localization which was mediated by JAK/STAT activation. These findings suggest IFITM1 overexpression contributes to breast cancer progression and that targeting IFITM1 may be therapeutically beneficial to patients with endocrine-resistant disease.

Glutathione-s-transferase A 4 (GSTA4) suppresses tumor growth and metastasis of human hepatocellular carcinoma by targeting AKT pathway

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies of cancers and its prognosis remains dismal due to the paucity of effective therapeutic targets. Up-regulation of glutathione-s-transferase A 4 (GSTA4) is associated with poor prognosis of HCC, but its functional mechanism in HCC remains unclear. In this study, we investigated the roles of GSTA4 in tumor growth and metastasis of HCC and found that GSTA4 was frequently up-regulated in HCC tissues. Through gain- and loss-of-function studies, GSTA4 was demonstrated to significantly regulate cell proliferation, migration, and invasion in vitro. Furthermore, GSTA4 overexpressing significantly promoted the tumorigenicity and metastasis of HCC cells in nude mice models bearing human HCC, whereas silencing endogenous GSTA4 caused an opposite outcome. Moreover, we demonstrated that GSTA4 enhanced HCC aggressiveness by activating protein kinase B (AKT) signaling. In multivariate analysis, our results GSTA4 overexpression promotes the progression of hepatocellular carcinoma and might represent a novel therapeutic target for its treatment.