Overview of the relevance of PI3K pathway in HR-positive breast cancer

MICAL-L2, as an estrogen-responsive gene, is involved in ER-positive breast cancer cell progression and tamoxifen sensitivity via the AKT/mTOR pathway

Endocrine treatment, particularly tamoxifen, has shown significant improvement in the prognosis of patients with estrogen receptor-positive (ER-positive) breast cancer. However, the clinical utility of this treatment is often hindered by the development of endocrine resistance. Therefore, a comprehensive understanding of the underlying mechanisms driving ER-positive breast cancer carcinogenesis and endocrine resistance is crucial to overcome this clinical challenge. In this study, we investigated the expression of MICAL-L2 in ER-positive breast cancer and its impact on patient prognosis. We observed a significant upregulation of MICAL-L2 expression in ER-positive breast cancer, which correlated with a poorer prognosis in these patients. Furthermore, we found that estrogen-ERβ signaling promoted the expression of MICAL-L2. Functionally, our study demonstrated that MICAL-L2 not only played an oncogenic role in ER-positive breast cancer tumorigenesis but also influenced the sensitivity of ER-positive breast cancer cells to tamoxifen. Mechanistically, as an estrogen-responsive gene, MICAL-L2 facilitated the activation of the AKT/mTOR signaling pathway in ER-positive breast cancer cells. Collectively, our findings suggest that MICAL-L2 could serve as a potential prognostic marker for ER-positive breast cancer and represent a promising molecular target for improving endocrine treatment and developing therapeutic approaches for this subtype of breast cancer.

Advances in dual-targeting inhibitors of HDAC6 for cancer treatment

Histone Deacetylase 6 (HDAC6) is an essential regulator of histone acetylation processes, exerting influence on a multitude of cellular functions such as cell motility, endocytosis, autophagy, apoptosis, and protein trafficking through its deacetylation activity. The significant implications of HDAC6 in diseases such as cancer, neurodegenerative disorders, and immune disorders have motivated extensive investigation into the development of specific inhibitors targeting this enzyme for therapeutic purposes. Single targeting drugs carry the risk of inducing drug resistance, thus prompting exploration of dual targeting therapy which offers the potential to impact multiple signaling pathways simultaneously, thereby lowering the likelihood of resistance development. While pharmacological studies have exhibited promise in combined therapy involving HDAC6, challenges related to potential drug interactions exist. In response to these challenges, researchers are investigating HDAC6 hybrid molecules which enable the concomitant targeting of HDAC6 and other key proteins, thus enhancing treatment efficacy while mitigating side effects and reducing the risk of resistance compared to traditional combination therapies. The published design strategies for dual targeting inhibitors of HDAC6 are summarized and discussed in this review. This will provide some valuable insights into more novel HDAC6 dual targeting inhibitors to meet the urgent need for innovative therapies in oncology and other related fields.

Phase III Randomized, Placebo-Controlled Trial of Endocrine Therapy ± 1 Year of Everolimus in Patients With High-Risk, Hormone Receptor-Positive, Early-Stage Breast Cancer

PURPOSE

Phosphatidylinositol 3-kinase/AKT-serine threonine kinase/mammalian target of rapamycin (mTOR) pathway abnormalities contribute to endocrine resistance. Everolimus, an mTOR inhibitor, improved progression-free survival in hormone receptor-positive metastatic breast cancer (BC) when combined with endocrine therapy (ET). In this phase III randomized, placebo-controlled trial, we assessed the efficacy of everolimus + ET as adjuvant therapy in high-risk, hormone receptor-positive, human epidermal growth factor receptor 2-negative BC after adjuvant/neoadjuvant chemotherapy.

METHODS

Patients were randomly assigned 1:1 to physician's choice ET and 1 year of everolimus (10 mg orally once daily) or placebo stratified by risk group. The primary end point was invasive disease-free survival (IDFS) evaluated by a stratified log-rank test with the hazard ratio (HR) estimated by Cox regression. Subset analyses included preplanned evaluation by risk group and exploratory analyses by menopausal status and age. Secondary end points included overall survival (OS) and safety. Everolimus did not improve IDFS/OS when added to ET in patients with early-stage high-risk, hormone receptor-positive BC.

RESULTS

One thousand and nine hundred thirty-nine patients were randomly assigned with 1,792 eligible for analysis. Overall, no benefit of everolimus was seen for IDFS (HR, 0.94 [95% CI, 0.77 to 1.14]) or OS (HR, 0.97 [95% CI, 0.75 to 1.26]). The assumption of proportional hazards was not met suggesting significant variability in the HR over time since the start of treatment. In an unplanned subgroup analysis among postmenopausal patients (N = 1,221), no difference in IDFS (HR, 1.08 [95% CI, 0.86 to 1.36]) or OS (HR, 1.19 [95% CI, 0.89 to 1.60]) was seen. In premenopausal patients (N = 571), everolimus improved both IDFS (HR, 0.64 [95% CI, 0.44 to 0.94]) and OS (HR, 0.49 [95% CI, 0.28 to 0.86]). Treatment completion rates were lower in the everolimus arm compared with placebo (48% v 73%) with higher grade 3 and 4 adverse events (35% v 7%).

CONCLUSION

One year of adjuvant everolimus + ET did not improve overall outcomes. Subset analysis suggests mTOR inhibition as a possible target for patients who remain premenopausal after chemotherapy.

Cracking the Genomic Code of CDK4/6 Inhibitor Resistance

The therapeutic approach to metastatic hormone receptor-positive, human epidermal growth factor-2-negative metastatic breast cancer (HR+/HER2- MBC) has evolved rapidly over recent years. The cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) have become first-line targeted agents of choice, in combination with an antiestrogen. Simultaneously, the clinical landscape of therapeutic options has been rapidly shifting, with novel antiestrogens, signal transduction inhibitors, and next-generation CDK inhibitors in various stages of development. Given these dynamic changes, understanding the genomic and molecular landscape of resistance to currently available antiestrogen therapy and CDK4/6 inhibitors represents a major focus of translational breast cancer research globally. See related article by Goetz et al., p. 2233.

Combined aromatase, CDK4/6 and PI3K blockade using letrozole/abemaciclib/LY3023414 in endometrial cancer

Several lines of preclinical evidence indicate that combining PI3K and CDK4/6 inhibitors may further enhance the efficacy of hormonal therapy by overcoming de novo and acquired resistance to PI3K and CDK4/6 blockade. We evaluated the combination of abemaciclib, letrozole and LY3023414 (an orally available, selective inhibitor of the class I PI3K isoforms and mTORC1/2) in recurrent endometrial cancer (EC). This study was terminated prematurely after 5 patients initiated protocol therapy due to discontinuation of further development of LY3023414. We report our findings from these patients, including one with recurrent endometrioid EC with AKT1, CTNNB1 and ESR1 hotspot mutations who had previously progressed through letrozole/everolimus and achieved a partial response to letrozole/abemaciclib/LY3023414.

Case report: Response to everolimus in a patient with platinum resistant, high grade serous ovarian carcinoma with biallelic TSC2 inactivation

Background

Patients with platinum-resistant recurrent high grade serous ovarian carcinoma have poor outcomes and limited treatment options.

Case presentation

We present a case of a 48-year-old woman with platinum-resistant high grade serous ovarian carcinoma harboring the pathogenic TSC2 R611Q variant with concomitant single copy loss of TSC2 (suggesting biallelic TSC2 inactivation) identified in targeted tumor sequencing. The patient was treated with the mTOR inhibitor everolimus, with an excellent response by imaging and a marked decrease in CA125; she remained on everolimus for 19 months until she developed progressive disease.

Conclusions

While mTOR inhibition is frequently used in tumors associated with tuberous sclerosis complex (TSC), such as lymphangioleiomyomatosis and malignant perivascular epithelioid cell tumors, this is the first case of a patient with ovarian cancer harboring TSC1/2 mutations who responded to mTOR inhibition. This case highlights the utility of targeted DNA sequencing in the management of ovarian carcinoma and demonstrates the value of tumor-agnostic targeted therapies.

Targeting the PI3K/AKT signaling pathway in anticancer research: a recent update on inhibitor design and clinical trials (2020-2023)

INTRODUCTION

Recent years have witnessed great achievements in drug design and development targeting the phosphatidylinositol 3-kinase/protein kinase-B (PI3K/AKT) signaling pathway, a pathway central to cell growth and proliferation. The nearest neighbor protein-protein interaction networks for PI3K and AKT show the interplays between these target proteins which can be harnessed for drug discovery. In this review, we discuss the drug design and clinical development of inhibitors of PI3K/AKT in the past three years. We review in detail the structures, selectivity, efficacy, and combination therapy of 35 inhibitors targeting these proteins, classified based on the target proteins. Approaches to overcoming drug resistance and to minimizing toxicities are discussed. Future research directions for developing combinational therapy and PROTACs of PI3K and AKT inhibitors are also discussed.

AREA COVERED

This review covers clinical trial reports and patent literature on inhibitors of PI3K and AKT published between 2020 and 2023.

EXPERT OPINION

To address drug resistance and drug toxicity of inhibitors of PI3K and AKT, it is highly desirable to design and develop subtype-selective PI3K inhibitors or subtype-selective AKT1 inhibitors to minimize toxicity or to develop allosteric drugs that can form covalent bonds. The development of PROTACs of PI3Kα or AKT helps to reduce off-target toxicities.

Mechanisms of Traditional Chinese medicine/natural medicine in HR-positive Breast Cancer: A comprehensive Literature Review

ETHNOPHARMACOLOGICAL RELEVANCE

With the emergence of endocrine resistance, the survival and good prognosis of HR-positive breast cancer (HR + BC) patients are threatened. As a common complementary and alternative therapy in cancer treatment, traditional Chinese medicine (TCM) has been widely used, and its internal mechanisms have been increasingly explored.

AIM OF THE REVIEW

In this review, the development status and achievements in understanding of the mechanisms related to the anti-invasion and anti-metastasis effects of TCM against HR + BC and the reversal of endocrine drug resistance by TCM in recent years have been summarized to provide ideas for antitumour research on the active components of TCM/natural medicine.

METHODS

We searched the electronic databases PubMed, Web of Science, and China National Knowledge Infrastructure database (CNKI) (from inception to July 2023) with the key words "HR-positive breast cancer" or "HR-positive breast carcinoma", "HR + BC" and "traditional Chinese medicine", "TCM", or "natural plant", "herb", etc., with the aim of elucidating the intrinsic mechanisms of traditional Chinese medicine and natural medicine in the treatment of HR + BC.

RESULTS

TCM/natural medicine monomers and formulas can regulate the expression of related genes and proteins through the PI3K/AKT, JAK2/STAT3, MAPK, Wnt and other signalling pathways, inhibit the proliferation and metastasis of HR + BC tumours, play a synergistic role in combination with endocrine drugs, and reverse endocrine drug resistance.

CONCLUSION

The wide variety of TCM/natural medicine components makes the research and development of new methods of TCM for BC treatments more selective and innovative. Although progress has been made on research on TCM/natural medicine, there are still many problems in clinical and basic experimental designs, and more in-depth scientific explorations and research are still needed.

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

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

Carcinogenic Role and Clinical Significance of Histone H3-H4 Chaperone Anti-silencing Function 1 B (ASF1B) in Lung Adenocarcinoma

Histone H3-H4 chaperone anti-silencing function 1 (ASF1) plays an important role in the polymerization, transport, and modification of histones. However, the significance of ASF1B in lung adenocarcinoma (LUAD) is largely overlooked. We investigated the aberrant expression of ASF1B in LUAD and its potential link to patient survival using multiple databases. ASF1B-overexpressing and knockdown cell lines were constructed to explore its effects on the biological behavior of lung cancer cells. ssGSEA, TMB, TIDE and IMvigor210 cohort were used to explore and validate the association of ASF1B to tumor immunity. Our data suggested that ASF1B was overexpressed in LUAD, and was associated with poor prognosis. ASF1B promoted the proliferation, migration, and invasion of lung cancer cells by regulating the phosphorylation of AKT in vitro. ASF1B was associated with tumor immunity. In summary, ASF1B may promote malignant behavior of LUAD cells, and its overexpression correlates with worse prognosis and better immunotherapy effect.

Liraglutide attenuates obese-associated breast cancer cell proliferation via inhibiting PI3K/Akt/mTOR signaling pathway

This study aims to explore the anti-proliferative, pro-apoptotic, and anti-migration activities of liraglutide (LGT) in MCF-7 breast cancer (BC) cells in subjects with obesity, particularly its effects on the PI3K/Akt/mTOR/AMPK pathway. The role of AMPK/SIRT-1, an essential regulator of adipokine production, in the effect of LGT on the production of adipose-derived adipokine was also assessed. MCF-7 cells were incubated in conditioned medium (CM) generated from adipose-derived stem cells (ADSCs) of obese subjects. MCF-7 cells were then treated with LGT for 72 h. Anti-proliferative, pro-apoptotic, and anti-migration activities were investigated using alamarBlue, annexin V stain, and scratch assay, respectively. Protein levels of phosphorylated PI3K, p-Akt, p-mTOR, and p-AMPK were investigated using immunoblotting. Levels of adipokines in ADSCs were determined using RT-PCR before and after transfection of ADSCs using the specific small interference RNA sequences for AMPK and SIRT-1. LGT evoked anti-proliferative, apoptotic, and potential anti-migratory properties on MCF-7 cells incubated in CM from obese ADSCs and significantly mitigated the activity of the PI3K/Akt/mTOR survival pathway-but not AMPK-in MCF-7 cells. Furthermore, the anti-proliferative effects afforded by LGT were similar to those mediated by LY294002 (PI3K inhibitor) and rapamycin (mTOR inhibitor). Our results reveal that transfection of AMPK/SIRT-1 genes did not affect the beneficial role of LGT in the expression of adipokines in ADSCs. In conclusion, LGT elicits anti-proliferative, apoptotic, and anti-migratory effects on BC cells in obese conditions by suppressing the activity of survival pathways; however, this effect is independent of the AMPK/SIRT1 pathway in ADSCs or AMPK in BC cells.

Genetic Testing Enhances the Precision Diagnosis and Treatment of Breast Cancer

The contemporary comprehension of breast cancer has progressed to the molecular level. As a heterogeneous malignancy, conventional pathological diagnosis and histological classification could no longer meet the needs of precisely managing breast cancer. Genetic testing based on gene expression profiles and gene mutations has emerged and substantially contributed to the precise diagnosis and treatment of breast cancer. Multigene assays (MGAs) are explored for early-stage breast cancer patients, aiding the selection of adjuvant therapy and predicting prognosis. For metastatic breast cancer patients, testing specific genes indicates potentially effective antitumor agents. In this review, genetic testing in early-stage and metastatic breast cancer is summarized, as well as the advantages and challenges of genetic testing in breast cancer.

FADS2 function at the major cancer hotspot 11q13 locus alters fatty acid metabolism in cancer

Dysregulation of fatty acid metabolism and de novo lipogenesis is a key driver of several cancer types through highly unsaturated fatty acid (HUFA) signaling precursors such as arachidonic acid. The human chromosome 11q13 locus has long been established as the most frequently amplified in a variety of human cancers. The fatty acid desaturase genes (FADS1, FADS2 and FADS3) responsible for HUFA biosynthesis localize to the 11q12-13.1 region. FADS2 activity is promiscuous, catalyzing biosynthesis of several unsaturated fatty acids by Δ6, Δ8, and Δ4 desaturation. Our main aim here is to review known and putative consequences of FADS2 dysregulation due to effects on the 11q13 locus potentially driving various cancer types. FADS2 silencing causes synthesis of sciadonic acid (5Z,11Z,14Z-20:3) in MCF7 cells and breast cancer in vivo. 5Z,11Z,14Z-20:3 is structurally identical to arachidonic acid (5Z,8Z,11Z,14Z-20:4) except it lacks the internal Δ8 double bond required for prostaglandin and leukotriene synthesis, among other eicosanoids. Palmitic acid has substrate specificity for both SCD and FADS2. Melanoma, prostate, liver and lung cancer cells insensitive to SCD inhibition show increased FADS2 activity and sapienic acid biosynthesis. Elevated serum mead acid levels found in hepatocellular carcinoma patients suggest an unsatisfied demand for arachidonic acid. FADS2 circular RNAs are at high levels in colorectal and lung cancer tissues. FADS2 circular RNAs are associated with shorter overall survival in colorectal cancer patients. The evidence thusfar supports an effort for future research on the role of FADS2 as a tumor suppressor in a range of neoplastic disorders.

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth factor signalling to transcription factors in the PAM axis is highly regulated by multiple cross-interactions with several other signaling pathways, and dysregulation of signal transduction can predispose to cancer development. The PAM axis is the most frequently activated signaling pathway in human cancer and is often implicated in resistance to anticancer therapies. Dysfunction of components of this pathway such as hyperactivity of PI3K, loss of function of PTEN, and gain-of-function of AKT, are notorious drivers of treatment resistance and disease progression in cancer. In this review we highlight the major dysregulations in the PAM signaling pathway in cancer, and discuss the results of PI3K, AKT and mTOR inhibitors as monotherapy and in co-administation with other antineoplastic agents in clinical trials as a strategy for overcoming treatment resistance. Finally, the major mechanisms of resistance to PAM signaling targeted therapies, including PAM signaling in immunology and immunotherapies are also discussed.

Prevalence of PIK3CA mutations in Taiwanese patients with breast cancer: a retrospective next-generation sequencing database analysis

Background

Breast cancer is the most common cancer type that affects women. In hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced breast cancer (ABC), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA) is the most frequently mutated gene associated with poor prognosis. This study evaluated the frequency of PIK3CA mutations in the Taiwanese breast cancer population.

Methodology

This is a retrospective study; patient data were collected for 2 years from a next-generation sequencing database linked to electronic health records (EHRs). The primary endpoint was the regional prevalence of PIK3CA mutation. The secondary endpoints were to decipher the mutation types across breast cancer subtype, menopausal status, and time to treatment failure after everolimus (an mTOR inhibitor) or cyclin-dependent kinase 4/6 (CDK4/6) inhibitor treatment.

Results

PIK3CA mutations were identified in 278 of 728 patients (38%). PIK3CA mutations were reported in 43% of patients with HR-/HER2+ subtype and 42% of patients with HR+/HER2- postmenopausal status. A lower prevalence of PIK3CA mutations was observed in triple-negative (27%) and HR+/HER2- premenopausal patients (29%). The most common mutation was at exon 20 (H1047R mutation, 41.6%), followed by exon 9 (E545K mutation, 18.9% and E542K mutation, 10.3%). Among patients treated with CDK4/6 inhibitors, the median time to treatment failure was 12 months (95% CI: 7-21 months) in the PIK3CA mutation cohort and 16 months (95% CI: 11-23 months) in the PIK3CA wild-type cohort, whereas patients receiving an mTOR inhibitor reported a median time to treatment failure of 20.5 months (95% CI: 8-33 months) in the PIK3CA mutation cohort and 6 months (95% CI: 2-9 months) in the PIK3CA wild-type cohort.

Conclusion

A high frequency of PIK3CA mutations was detected in Taiwanese patients with breast cancer, which was consistent with previous studies. Early detection of PIK3CA mutations might influence therapeutic decisions, leading to better treatment outcomes.

Crosstalk between ferroptosis and steroid hormone signaling in gynecologic cancers

Ferroptosis is a novel types of regulated cell death and is widely studied in cancers and many other diseases in recent years. It is characterized by iron accumulation and intense lipid peroxidation that ultimately inducing oxidative damage. So far, signaling pathways related to ferroptosis are involved in all aspects of determining cell fate, including oxidative phosphorylation, metal-ion transport, energy metabolism and cholesterol synthesis progress, et al. Recently, accumulated studies have demonstrated that ferroptosis is associated with gynecological oncology related to steroid hormone signaling. This review trends to summarize the mechanisms and applications of ferroptosis in cancers related to estrogen and progesterone, which is expected to provide a theoretical basis for the prevention and treatment of gynecologic cancers.

Analysis of active components and molecular mechanism of action of Rubia cordifolia L. in the treatment of nasopharyngeal carcinoma based on network pharmacology and experimental verification

The aim of this study is to explore the active components and potential molecular mechanism of action of Rubia cordifolia L. against nasopharyngeal carcinoma (NPC). We used network pharmacology, molecular docking, and bioinformatics analysis to identify the active components and their role against NPC. The experimental verification was detected by MTT, AnnexinV-FITC/PI double fluorescence staining and Western blotting method. Network pharmacology identified that mollugin is one of the most effective components inRubia cordifolia L. Important NPC targets included HSP90AA1, CDK1, EGFR, PIK3CA, MAPK14, and CDK2. Molecular docking revealed considerable binding activity of mollugin with either of the 6 important NPC targets. Bioinformatics analysis showed that these 6 important targets were mutated in NPC, and the expression of HSP90AA1, PIK3CA, and CDK2 in cancer tissues was significantly different from that in normal tissues. MTT detection and AnnexinV-FITC/PI double fluorescence staining showed that mollugin inhibited the proliferation and induced apoptosis of NPC cells. Western blotting indicated that the molecular mechanism of mollugin against NPC was related to the regulation of the expression of Survivin and XIAP. This study predicted and partially verified the pharmacological and molecular mechanism of action of Rubia cordifolia L. against NPC. Mollugin was identified as a potential active ingredient against NPC. These results prove the reliability of network pharmacology approaches and provide a basis for further research and application of Rubia cordifolia L. against NPC.

Addition of PI3K/AKT/mTOR inhibitors to fulvestrant for advanced HR+/HER2- breast cancer: a systematic review and meta-analysis

Purpose: To analyze whether adding PI3K/AKT/mTOR inhibitors to fulvestrant could restore endocrine therapy sensitivity for the treatment of postmenopausal patients with HR+, HER2- breast cancer. Methods: This meta-analysis was performed using RevMan 5.4 analysis software. Results: Nine studies that included a total of 3199 patients were analyzed. Compared with fulvestrant alone, the addition of PI3K/AKT/mTOR inhibitors significantly prolonged progression-free survival, overall survival and objective response rate of patients in both the total and PI3K-pathway-activated population. The number of grade 3-5 adverse events was also significantly higher. Conclusion: The addition of PI3K/AKT/mTOR to fulvestrant resulted in potential benefits; however, there may be a higher risk, which needs to be carefully managed.

Oxypalmatine regulates proliferation and apoptosis of breast cancer cells by inhibiting PI3K/AKT signaling and its efficacy against breast cancer organoids

BACKGROUND

Breast cancer (BC) is known as the most common cancer in women. Discovering novel and effective drugs is a priority for the treatment of BC. Oxypalmatine (OPT) is a natural protoberberine-type alkaloid isolated from Phellodendron amurense Rupr. (Rutaceae) with potential anti-cancer activity.

PURPOSE

This investigation aimed to elucidate the biological role and potential mechanisms of OPT in BC cells, and intended to assess the therapeutic potential of OPT in BC patient-derived organoid models.

METHODS

CCK-8 and EdU assays, and flow cytometry were used to test the activity of OPT against BC cells. In addition, patient-derived organoid models were constructed to assess the therapeutic efficiency of OPT in BC. Besides, network pharmacological analysis and RNA sequencing analysis were performed to predict the underlying anti-BC mechanism of OPT. Moreover, Western blot analysis was applied to test the expression of genes modulated by OPT.

RESULTS

OPT attenuated the proliferation and DNA replication, and induced apoptosis in multiple BC cells. Interestingly, OPT also exerted a cytotoxic effect on BC organoids characterized as luminal A, HER2-overexpressing, and triple-negative subtypes, indicating that OPT was a potential broad-spectrum anticancer drug. Network pharmacological analysis suggested that OPT might affect signals contributing to BC progression, including PI3K/AKT, MAPK, and VEGFA-VEGFR2 signaling pathways. Moreover, bioinformatics analysis of data from our RNA sequencing suggested that PI3K/AKT was a downstream pathway of OPT in BC. Finally, OPT was shown to inactivate PI3K/AKT signaling pathway in BC cells by Western blot analysis.

CONCLUSIONS

Collectively, our study demonstrated that OPT suppressed proliferation and induced apoptosis through mitigating the PI3K/AKT signaling pathway in BC cells. Moreover, our work first adopted BC organoid models to confirm OPT as an effective and promising drug, laying a foundation for the potential use of OPT in BC treatment.

Estrogen/HER2 receptor crosstalk in breast cancer: combination therapies to improve outcomes for patients with hormone receptor-positive/HER2-positive breast cancer

The human epidermal growth factor receptor 2 (HER2) is overexpressed in 13-22% of breast cancers (BC). Approximately 60-70% of HER2+ BC co-express hormone receptors (HRs). HR/HER2 co-expression modulates response to both anti-HER2-directed and endocrine therapy due to "crosstalk" between the estrogen receptor (ER) and HER2 pathways. Combined HER2/ER blockade may be an effective treatment strategy for patients with HR+/HER2+ BC in the appropriate clinical setting(s). In this review, we provide an overview of crosstalk between the ER and HER2 pathways, summarize data from recently published and ongoing clinical trials, and discuss clinical implications for targeted treatment of HR+/HER2+ BC.

Reduction of daily-use parabens and phthalates reverses accumulation of cancer-associated phenotypes within disease-free breast tissue of study subjects

Estrogenic overstimulation is carcinogenic to the human breast. Personal care products (PCPs) commonly contain xenoestrogens (XE), such as parabens and phthalates. Here, we identified the adverse effects of persistent exposure to such PCPs directly within human estrogen responsive breast tissue of subjects enrolled in a regimen of reduced XE use (REDUXE). Pre- and post-intervention fine needle aspirates (FNAs) of the breast were collected from healthy volunteers who discontinued the use of paraben and phthalate containing PCPs over a 28 d period. Based on high-dimensional gene expression data of matched FNA pairs of study subjects, we demonstrate a striking reversal of cancer-associated phenotypes, including the PI3K-AKT/mTOR pathway, autophagy, and apoptotic signaling networks within breast cells of REDUXE compliant subjects. These, and other altered phenotypes were detected together with a significant reduction in urinary parabens and phthalate metabolites. Moreover, in vitro treatment of paired FNAs with 17β-estradiol (E2), displayed a 'normalizing' impact of REDUXE on gene expression within known E2-modulated pathways, and on functional endpoints, including estrogen receptor alpha: beta ratio, and S-phase fraction of the cell cycle. In a paradigm shifting approach facilitated by community-based participatory research, REDUXE reveals unfavorable consequences from exposure to XEs from daily-use PCPs. Our findings illustrate the potential for REDUXE to suppress pro-carcinogenic phenotypes at the cellular level towards the goal of breast cancer prevention.

MIR497HG-Derived miR-195 and miR-497 Mediate Tamoxifen Resistance via PI3K/AKT Signaling in Breast Cancer

Tamoxifen is commonly used for the treatment of patients with estrogen receptor-positive (ER+) breast cancer, but the acquired resistance to tamoxifen presents a critical challenge of breast cancer therapeutics. Recently, long noncoding RNA MIR497HG and its embedded miR-497 and miR-195 are proved to play significant roles in many types of human cancers, but their roles in tamoxifen-resistant breast cancer remain unknown. The results indicate that MIR497HG deficiency induces breast cancer progression and tamoxifen resistance by inducing downregulation of miR-497/195. miR-497/195 coordinately represses five positive PI3K-AKT regulators (MAP2K1, AKT3, BCL2, RAF1, and CCND1), resulting in inhibition of PI3K-AKT signaling, and PI3K-AKT inhibition in tamoxifen-resistant cells restored tamoxifen responsiveness. Furthermore, ER α binds the MIR497HG promoter to activate its transcription in an estrogen-dependent manner. ZEB1 interacts with HDAC1/2 and DNMT3B at the MIR497HG promoter, resulting in promoter hypermethylation and histone deacetylation. The findings reveal that ZEB1-induced MIR497HG depletion contributes to breast cancer progression and tamoxifen resistance through PI3K-AKT signaling. MIR497HG can be used as a biomarker for predicting tamoxifen sensitivity in patients with ER+ breast cancer.

E2F1-mediated ectopic expression of PP1A promotes breast cancer progression via activation of YAP1

Hormone receptor-positive breast cancer is the most common subtype of breast cancer. The protein phosphatase PP1A gene is described as an oncogene in several tumor types; however, the biological function of PP1A in hormone receptor-positive breast cancer remains unclear. The Cancer Genome Atlas data indicates PP1A expression is upregulated in hormone receptor-positive breast cancer tissues than in normal breast tissues. We explored the biological function of PP1A in hormone receptor-positive breast cancer using MTT assays, colony formation assays, and a xenograft mouse model. The results indicated that PP1A promoted hormone receptor-positive breast cancer proliferation, both in vitro and in vivo. Mechanistically, LINC02754 recruited the binding of the transcription factor E2F1 to the PP1A promotor, thereby increasing PP1A expression. The PP1A then interacted with and dephosphorylated YAP1, resulting in YAP1 activation. The dephosphorylated YAP1 moved to the nucleus and increased the expression of the downstream oncogene CTGF, promoting hormone receptor-positive breast cancer progression. Our findings reveal the function of the LINC02754/E2F1/PP1A/YAP1 axis in hormone receptor-positive breast cancer and provide new insight into hormone receptor-positive breast cancer progression.

Phosphorylation of AKT by lysyl oxidase-like 2 activates the PI3K/AKT signaling pathway to promote proliferation, invasion and metastasis in esophageal squamous carcinoma

OBJECTIVE

Esophageal squamous cell carcinoma (ESCC) is a common and aggressive malignancy of the gastrointestinal tract for which therapeutic options are scarce. This study screens for LOXL2, a key gene in ESCC, and explains the molecular mechanism by which it promotes the progression of ESCC.

METHODS

Immunohistochemical staining was performed to detect the expression level of LOXL2 in ESCC tissues and paraneoplastic tissues. CCK-8 and Transwell assays were performed to assess the effects of LOXL2 knockdown and overexpression on the proliferation, apoptosis, migration and invasion ability of ESCC cells. High-throughput sequencing analysis screens for molecular mechanisms of action by which LOXL2 promotes ESCC progression. Western blotting and qRT-PCR were used to determine the expression levels of relevant markers.

RESULTS

LOXL2 is positively expressed in ESCC and highly correlated with poor prognosis. Silencing LOXL2 significantly inhibited the proliferation, migration and invasive ability of ESCC cells, whereas overexpression showed the opposite phenotype. High-throughput sequencing suggested that LOXL2-associated differentially expressed genes were highly enriched in the PI3K/AKT signaling pathway. In vitro cellular assays confirmed that silencing LOXL2 significantly reduced PI3K, p-AKT^Thr308 and p-AKT^Ser473 gene and protein expression levels, while overexpression increased all three gene and protein levels, while AKT gene and protein expression levels were not significantly different.

CONCLUSION

This study found that LOXL2 may regulate the PI3K/AKT signaling pathway and exert protumor effects on ESCC cells through phosphorylation of AKT. LOXL2 may be a key clinical warning biomarker or therapeutic target for ESCC.

Filling the Gap after CDK4/6 Inhibitors: Novel Endocrine and Biologic Treatment Options for Metastatic Hormone Receptor Positive Breast Cancer

The rise of cyclin-dependent kinase (CDK)4/6 inhibitors has rapidly reshaped treatment algorithms for hormone receptor (HR)-positive metastatic breast cancer, with endocrine treatment (ET) plus a CDK4/6-inhibitor currently representing the standard of care in the first line setting. However, treatment selection for those patients experiencing progression while on ET + CDK4/6-inhibitors remains challenging due to the suboptimal activity or significant toxicities of the currently available options. There is also a paucity of data regarding the efficacy of older regimens, such as everolimus + exemestane, post-CDK4/6 inhibition. In this setting of high unmet need, several clinical trials of novel drugs have recently reported encouraging results: the addition of the AKT-inhibitor capivasertib to fulvestrant demonstrated a significant improvement in progression-free survival (PFS); the oral selective estrogen receptor degrader (SERD) elacestrant prolonged PFS compared to traditional ET in a phase 3 trial, particularly among patients with detectable ESR1 mutations; finally, PARP inhibitors are available treatment options for patients with pathogenic BRCA1/2 germline mutations. Overall, a plethora of novel endocrine and biologic treatment options are finally filling the gap between first-line ET and later line chemotherapy. In this review article, we recapitulate the activity of these novel treatment options and their potential role in future treatment algorithms.

P-15 promotes chondrocyte proliferation in osteoarthritis by regulating SFPQ to target the Akt-RUNX2 axis

BACKGROUND

The disruption of chondrocyte proliferation and differentiation is a critical event during the process of joint injury in osteoarthritis (OA). P-15 peptides could bind to integrin receptors on various precursor cells, promote cell adhesion, release growth factors, and promote the differentiation of osteoblast precursor cells. However, the role of P-15 in OA, particularly in chondrocyte proliferation, is not fully understood.

METHODS

The activity of SFPQ and RUNX2 in the bone tissue of patients with osteoarthritis was analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). Interleukin-1β (IL-1β) inducer was performed to establish an in vitro model of OA. Cell proliferation was measured by CCK-8 assay. The expressions of COL2a1, ACAN, COMP, SOX9, and BMP2 related to cartilage differentiation were detected using qRT-PCR. In addition, the expression levels of SFPQ, AKT, p-AKT, and RUNX2 were detected using Western blotting.

RESULTS

The results showed that the expression of SFPQ was significantly decreased and the expression of RUNX2 was significantly increased in osteoarthritis cartilage tissue. P-15 peptide reversed IL-1β-induced cell proliferation obstruction and alleviated chondrocyte damage. Furthermore, P-15 polypeptide increased the expression levels of cartilage differentiation genes COL2a1, ACAN, and BMP2, while decreasing the expression of COMP and SOX9 in an inverse dose-dependent manner. Then specific interfering RNA proved that P-15 maintains chondrocyte stability and is associated with the SFPQ gene. Finally, we confirmed that P-15 inhibited the Akt-RUNX2 pathway, which is regulated in the expression of SFPQ.

CONCLUSIONS

P-15 can mitigate chondrocyte damage and osteoarthritis progression by inhibiting cell death and modulating SFPQ-Akt-RUNX2 pathway, offering an opportunity to develop new strategies for the treatment of osteoarthritis.

The prognostic and predictive values of differential expression of exosomal receptor tyrosine kinases and associated with the PI3K/AKT/mTOR signaling in breast cancer patients undergoing neoadjuvant chemotherapy

PURPOSE

Cancer cell-derived exosomes are the mediator of the tumor microenvironment and the molecular content of exosomes presents a promising prognostic or predictive marker in tumor progression and the treatment response of cancer patients. The aim of this study was to identify the expression levels of receptor tyrosine kinases (RTKs) and AKT1 and mTOR before and after neoadjuvant chemotherapy (NACT) in the exosomes of BC patients compared with healthy females.

METHODS

After isolating exosomes in the serum of 25 BC patients and characterization by flow cytometry, the mRNA levels of FGFR2, FGFR3, PDGFRB, AKT1 and mTOR in the exosomes were analyzed by RT-PCR.

RESULTS

Our preliminary findings showed that FGFR2, PDGFRB, AKT1 and mTOR levels were significantly upregulated in BC patients before NACT compared with the healthy group (p < 0.05). Furthermore, the mRNA levels PDGFRB and AKT1 were significantly down-regulated after NACT compared with control. PDGFRB expression level could predict pathological non-response and significantly correlated with tumor size after NACT.

CONCLUSION

Therefore, especially FGFR2, PDGFRB and AKT1 could be a therapeutic target as a prognostic marker, whereas PDGFRB may be a promising predictive indicator of therapy response in BC patients. However, the prognostic or predictive role of RTKs and PI3K/AKT/mTOR signaling in the exosomes should be further investigated in a large patient population.

Pharmacokinetics and Pharmacodynamic of Alpelisib

Advanced breast cancers are frequently hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (HER2)-negative. Some of them harbor a mutation in PIK3CA, a gene encoding the PI3K catalytic subunit α of phosphatidyl-inositol 3-kinase (PI3K), which confers resistance to hormone therapy. Alpelisib is the first oral selective p110 [Formula: see text] PI3K inhibitor approved by FDA and EMA, in association with fulvestrant, based on PFS improvement as compared to fulvestrant alone. The aim of this review is to summarize and critically review the key aspects of alpelisib pharmacokinetics (PK) and pharmacodynamics (PD). Preclinical data have shown that alpelisib IC₅₀ was 50 times lower for the α enzyme than for the β, δ and γ PI3K enzymes, leading to a decrease in intra-tumoral AKT phosphorylation. The PK properties of alpelisib are somehow favorable, with a rapid and important absorption, a limited CYP P450-mediated metabolism and a predominant biliary excretion, with a half-life of 17.5 ± 5.9 h. Only limited drug-drug interactions are expected and there is no need for dose adaptation in mild and moderate renal impaired and mild to severe hepatic impaired patients. Pharmacokinetic/pharmacodynamic relationships were evidenced during drug development for exposure/efficacy, but also exposure/safety. Main adverse events are hyperglycemia, rash, and diarrhea. The first, if not fully contra-indicated in (pre-)diabetic patients, warrants a close follow up when treatment is started and a potential dose reduction when needed. Because of its safety profile, alpelisib require stringent patient selection and close follow-up.

Targeting PI3K/AKT/mTOR Pathway in Breast Cancer: From Biology to Clinical Challenges

Breast cancer (BC) is the most common women cancer and cause of cancer death. Despite decades of scientific progress in BC treatments, the clinical benefit of new drugs is modest in several cases. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway mutations are frequent in BC (20-40%) and are significant causes of aggressive tumor behavior, as well as treatment resistance. Improving knowledge of the PI3K/AKT/mTOR pathway is an urgent need. This review aims to highlight the central role of PI3K-mTORC1/C2 mutations in the different BC subtypes, in terms of clinical outcomes and treatment efficacy. The broad base of knowledge in tumor biology is a key point for personalized BC therapy in the precision medicine era.

The ubiquitin ligase RNF2 stabilizes ERα and modulates breast cancer progression

Estrogen receptor α (ERα) is the most common clinical marker used for breast cancer prognosis and the classification of breast cancer subtypes. Clinically, patients with estrogen receptor-positive breast cancer can receive endocrine therapy. However, resistance to endocrine therapy has become an urgent clinical problem. A large number of previous studies have proven that posttranslational modification of the estrogen receptor is significantly related to endocrine therapy resistance. RNF2 is a member of the RING finger protein family that functions as an E3 ubiquitin ligase. Several studies have clarified that RNF2 is a critical regulator of ERα transcriptional regulation. In our current study, we identified RNF2 as an important posttranslational modification regulator of the estrogen receptor. RNF2 depletion inhibited breast cancer cell progression and ERα signaling activity. TCGA data analysis indicated that RNF2 was elevated in breast malignancies, while RNF2 depletion could drastically inhibit estrogen response gene expression on a whole-genome scale. TCGA data analysis revealed that RNF2 was positively correlated with ERα target gene expression. Further mechanistic studies showed that RNF2 was mainly localized in the nucleus and associated with ERα. The association increased ERα stability by inhibiting ERα K48-linked polyubiquitination. In conclusion, our study implicates nongenomic regulation by RNF2 on ERα protein stability and suggests that targeting RNF2 could be a promising strategy for breast cancer treatments.

TG2 as a novel breast cancer prognostic marker promotes cell proliferation and glycolysis by activating the MEK/ERK/LDH pathway

BACKGROUND

Breast cancer (BC) is the most common malignant tumor among women worldwide. Tissue transglutaminase 2 (TG2) has been reported as a major player across several types of cancer. However, the effects of TG2 in breast cancer are less known.

METHODS

The expression of TG2 in patients with BC was detected by immunochemistry staining and RT-qPCR. The correlation of TG2 expression and clinicopathological factors or overall survival (OS) was analyzed by Chi-square test, Kaplan-Meier, and Cox-regression analysis. The effects of TG2 on cell proliferation and glycolysis were investigated in vivo and in vitro by gain- and loss-of-function experiments.

RESULT

Both mRNA and protein levels of TG2 were overexpressed in BC tissues and cultured cells. Clinical stage (p = 0.011), molecular subtype (p<0.001) and survival status (p<0.001) were significantly correlated with TG2 expression. Specifically, TG2 expression was positively associated with the clinical stage (r = 0.193, p = 0.005) and OS (r = 0.230, p = 0.001), while negatively associated with molecular subtype (r = - 0.161, p = 0.020). Overexpressed TG2 was a prognostic factor of poor OS by Cox-regression analysis. Gain- and loss-of-function experiments indicated that cell proliferation and glycolysis were regulated by TG2 via the MEK/ERK/LDH pathway. TG2-induced activation of the MEK/ERK/LDH pathway and glycolysis were attenuated by MEK inhibitor U0126.

CONCLUSION

TG2 is overexpressed in BC, which can serve as an independent prognostic factor for OS. TG2 promotes tumor cell proliferation and increases glycolysis associated with the activation of the MEK/ERK/LHD pathway.

'Why is survival with triple negative breast cancer so low? insights and talking points from preclinical and clinical research'

INTRODUCTION

Triple negative breast cancer is typically related to poor prognosis, early metastasis, and high recurrence rate. Intrinsic and extrinsic biological features of TNBC and resistance mechanisms to conventional therapies can support its aggressive behavior, characterizing TNBC how extremely heterogeneous. Novel combination strategies are under investigation, including immunotherapeutic agents, anti-drug conjugates, PARP inhibitors, and various targeting agents, exploring, in the meanwhile, possible predictive biomarkers to correctly select patients for the optimal treatment for their specific subtype.

AREAS COVERED

This article examines the main malignity characteristics across different subtype, both histological and molecular, and the resistance mechanisms, both primary and acquired, to different drugs explored in the landscape of TNBC treatment, that lead TNBC to still has high mortality rate.

EXPERT OPINION

The complexity of TNBC is not only the main reason of its aggressivity, but its heterogeneity should be exploited in terms of therapeutics opportunities, combining agents with different mechanism of action, after a correct selection by biologic or molecular biomarkers. The main goal is to understand what TNBC really is and to act selectively on its characteristics, with a personalized anticancer treatment.

First-in-human phase Ia study of the PI3Kα inhibitor CYH33 in patients with solid tumors

PIK3CA mutations are highly prevalent in solid tumors. Targeting phosphatidylinositol 3-kinase α is therefore an attractive strategy for treating cancers harboring PIK3CA mutations. Here, we report the results from a phase Ia, open label, dose-escalation and -expansion study (NCT03544905) of CYH33, a highly selective PI3Kα inhibitor, in advanced solid tumors. The primary outcomes were the safety, tolerability, maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of CYH33. The secondary outcomes included evaluation of pharmacokinetics, preliminary efficacy and changes in pharmacodynamic biomarkers in response to CYH33 treatment. The exploratory outcome was the relationship between the efficacy of CYH33 treatment and tumor biomarker status, including PIK3CA mutations. A total of 51 patients (19 in the dose escalation stage and 32 in the dose expansion stage) including 36 (70.6%) patients (4 in the dose escalation stage and 32 in the dose expansion stage) with PIK3CA mutations received CYH33 1-60 mg. The MTD of CYH33 was 40 mg once daily, which was also selected as the RP2D. The most common grade 3/4 treatment-related adverse events were hyperglycemia, rash, platelet count decreased, peripheral edema, and fatigue. Forty-two out of 51 patients were evaluable for response, the confirmed objective response rate was 11.9% (5/42). Among 36 patients harboring PIK3CA mutations, 28 patients were evaluable for response, the confirmed objective response rate was 14.3% (4/28). In conclusion, CYH33 exhibits a manageable safety profile and preliminary anti-tumor efficacy in solid tumors harboring PIK3CA mutations.

Everolimus Added to Adjuvant Endocrine Therapy in Patients With High-Risk Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Primary Breast Cancer

PURPOSE

Everolimus, an oral inhibitor of the mammalian target of rapamycin, improves progression-free survival in combination with endocrine therapy (ET) in postmenopausal women with aromatase inhibitor-resistant metastatic breast cancer. However, the benefit of adding everolimus to ET in the adjuvant setting in early breast cancer is unknown.

PATIENTS AND METHODS

In this randomized double-blind phase III study, women with high-risk, hormone receptor-positive, human epidermal growth factor receptor 2-negative primary breast cancer were randomly assigned to everolimus or placebo for 2 years combined with standard ET. Stratification factors included ET agent, receipt of neoadjuvant versus adjuvant chemotherapy, progesterone receptor status, duration of ET before random assignment, and lymph node involvement. The primary end point was disease-free survival (DFS). The trial is registered with ClinicalTrials.gov (identifier: NCT01805271).

RESULTS

Between June 2013 and March 2020, 1,278 patients were randomly allocated to receive everolimus or placebo. At the first interim analysis, the trial was stopped for futility and a full analysis undertaken once data snapshot complete. One hundred forty-seven patients have had a DFS event reported and at 3 years, DFS did not differ between patients who received ET plus everolimus (88% [95% CI, 85 to 91]) or ET plus placebo (89% [95% CI, 86 to 91; hazard ratio, 0.95; 95% CI, 0.69 to 1.32; P = .77]). Grade ≥ 3 adverse events were reported in 22.9% of patients (29.9% with everolimus v 15.9% with placebo, P < .001). 53.4% everolimus-treated patients permanently discontinued experimental treatment early compared with placebo-treated 22.3%.

CONCLUSION

Among high-risk patients, everolimus added to adjuvant ET did not improve DFS. Tolerability was a concern, with more than half of patients stopping everolimus before study completion. Everolimus cannot be recommended in the adjuvant setting.

Thermal stress involved in TRPV2 promotes tumorigenesis through the pathways of HSP70/27 and PI3K/Akt/mTOR in esophageal squamous cell carcinoma

BACKGROUND

The transient receptor potential vanilloid receptor 2 (TRPV2) has been found to participate in the pathogenesis of various types of cancers, however, its role(s) in the tumorigenesis of ESCC remain poorly understood.

METHODS

Western blotting and immunohistochemistry were performed to determine the expression profiles of TRPV2 in the ESCC patient tissues. A series of in vitro and in vivo experiments were conducted to reveal the role of TRPV2 in the tumorigenesis of ESCC.

RESULTS

Our study first uncovered that the activation of TRPV2 by recurrent acute thermal stress (54 °C) or O1821 (20 μM) promoted cancerous behaviours in ESCC cells. The pro-angiogenic capacity of the ESCC cells was found to be enhanced profoundly and both tumour formation and metastasis that originated from the cells were substantially promoted in nude mouse models upon the activation of TRPV2. These effects were inhibited significantly by tranilast (120 μM) and abolished by TRPV2 knockout. Conversely, overexpression of TRPV2 could switch the cells to tumorigenesis upon activation of TRPV2. Mechanistically, the driving role of TRPV2 in the progression of ESCC is mainly regulated by the HSP70/27 and PI3K/Akt/mTOR signalling pathways.

CONCLUSIONS

We revealed that TRPV2-PI3K/Akt/mTOR is a novel and promising target for the prevention and treatment of ESCC.

PIK3CAMutations in Breast Cancer Subtypes Other Than HR-Positive/HER2-Negative

The phosphoinositide 3-kinase (PI3K) pathway plays a key role in cancer, influencing growth, proliferation, and survival of tumor cells. PIK3CA mutations are generally oncogenic and responsible for uncontrolled cellular growth. PI3K inhibitors (PI3Ki) can inhibit the PI3K/AKT/mTOR pathway, although burdened by not easily manageable toxicity. Among PI3Ki, alpelisib, a selective p110α inhibitor, is approved for the treatment of hormone receptor (HR)+/HER2- PIK3CA mutant metastatic breast cancer (BC) that has progressed to a first line endocrine therapy. PIK3CA mutations are also present in triple negative BC (TNBC) and HER2+ BC, although the role of PI3K inhibition is not well established in these subtypes. In this review, we go through the PI3K/AKT/mTOR pathway, describing most common mutations found in PI3K genes and how they can be detected. We describe the available biological and clinical evidence of PIK3CA mutations in breast cancers other than HR+/HER2-, summarizing clinical trials investigating PI3Ki in these subtypes.

Design, synthesis and computational study of new benzofuran hybrids as dual PI3K/VEGFR2 inhibitors targeting cancer

Design and synthesis of a new series of benzofuran derivatives has been performed. ¹H-NMR, ¹³C-NMR, elemental analysis, and IR were used to confirm the structures of the produced compounds. Hepatocellular carcinoma (HePG2), mammary gland breast cancer (MCF-7), epithelioid carcinoma cervical cancer (Hela), and human prostate cancer are used to test anticancer activity (PC3). In compared to DOX (4.17-8.87 µM), Compound 8 demonstrated the highest activity against HePG and PC3 cell lines, with an IC₅₀ range of 11-17 µM. Compound 8 inhibited PI3K and VEGFR-2 with IC₅₀ values of 2.21 and 68 nM, respectively, compared to 6.18 nM for compound LY294002 and 31.2 nM for compound sorafenib as PI3K and VEGFR-2 reference inhibitors, selectively. The molecular docking and binding affinity of the generated compounds were estimated and studied computationally utilizing molecular operating environment software as a PI3K and VEGFR-2 inhibitor (MOE). In conclusion, compound 8 exhibited significant action against hepatocellular and cervical cancer cell lines. Mechanistic study showed that it had a dual inhibitory effect against PI3K and VEGFR-2.

HK2: a potential regulator of osteoarthritis via glycolytic and non-glycolytic pathways

Osteoarthritis (OA) is an age-related chronic degenerative joint disease where the main characteristics include progressive degeneration of cartilage, varying degrees of synovitis, and periarticular osteogenesis. However, the underlying factors involved in OA pathogenesis remain elusive which has resulted in poor clinical treatment effect. Recently, glucose metabolism changes provide a new perspective on the pathogenesis of OA. Under the stimulation of external environment, the metabolic pathway of chondrocytes tends to change from oxidative phosphorylation (OXPHOS) to aerobic glycolysis. Previous studies have demonstrated that glycolysis of synovial tissue is increased in OA. The hexokinase (HK) is the first rate limiting enzyme in aerobic glycolysis, participating and catalyzing the main pathway of glucose utilization. An isoform of HKs, HK2 is considered to be a key regulator of glucose metabolism, promotes the transformation of glycolysis from OXPHOS to aerobic glycolysis. Moreover, the expression level of HK2 in OA synovial tissue (FLS) was higher than that in control group, which indicated the potential therapeutic effect of HK2 in OA. However, there is no summary to help us understand the potential therapeutic role of glucose metabolism in OA. Therefore, this review focuses on the properties of HK2 and existing research concerning HK2 and OA. We also highlight the potential role and mechanism of HK2 in OA.

Suppressing the PI3K/AKT Pathway by miR-30d-5p Mimic Sensitizes Ovarian Cancer Cells to Cell Death Induced by High-Dose Estrogen

MicroRNAs are short non-coding RNA molecules that are involved in tumor development and are considered to be promising candidates in cancer therapy. Here, we studied the role of miR-30s in the pathophysiology of ovarian cancer. According to our results miR-30a-5p, miR-30d-5p, and miR-30e-5p were overexpressed in the estrogen receptor α (ERα)-expressing PEO1 cell line compared to A2780 that lacks this receptor. Furthermore, the expression of miR-30a-5p, miR-30d-5p, and miR-30e-5p were induced in response to high-dose estrogen treatment in PEO1 where intensive cell death was observed according to the induction of apoptosis and autophagy. Lacking or blocking ERα function reduced tolerance to high-dose estrogen that suggests the importance of ERα-mediated estrogen response in the maintenance of proliferation. MiR-30d-5p mimic reduced cell proliferation in both A2780 and PEO1. Furthermore, it decreased the tolerance of PEO1 cells to high-dose estrogen by blocking the ERα-mediated estrogen response. This was accompanied by decreased SOX4 expression that is thought to be involved in the regulation of the PI3K/AKT pathway. Blocking this pathway by AZD8835 led to the same results. MiR-30d-5p or AZD8835 sensitized PEO1 cells to tamoxifen. We suggest that miR-30d-5p might be a promising candidate in the therapy of ovarian cancer.

Targeted therapy for breast cancer: An overview of drug classes and outcomes

The last 25 years have seen significant growth in new therapeutic options for breast cancer, termed targeted therapies based on their ability to block specific pathways known to drive breast tumor growth and survival. Introduction of these drugs has been made possible through advances in the understanding of breast cancer biology. While the promise of targeted therapy for breast cancer has been clear for some time, the experience of the clinical use of multiple drugs and drug classes allows us to now present a summary and perspective as to the success and impact of this endeavor. Here we will review breast cancer targeted therapeutics in clinical use. We will provide the rationale for their indications and summarize clinical data in patients with different breast cancer subtypes, their impact on breast cancer progression and survival and their major adverse effects. The focus of this review will be on the development that has occurred within classes of targeted therapies and subsequent impact on breast cancer patient outcomes. We will conclude with a perspective on the role of targeted therapy in breast cancer treatment and highlight future areas of development.

Treatment patterns and clinical outcomes in patients with metastatic breast cancer treated with palbociclib-based therapies: real-world data in the Han population

BACKGROUND

This study aimed to reveal the treatment patterns and clinical outcomes of diverse palbociclib-based regimens in Han patients with estrogen receptor-positive (ER+) metastatic breast cancer in routine clinical practice.

METHODS

The clinical data of patients with ER+ metastatic breast cancer treated with palbociclib were collected from the National Cancer Center database. The efficacy profile of palbociclib in this Han population was evaluated, especially for various combination regimens. The efficacy of palbociclib-based therapy in patients with prior everolimus treatment was also assessed.

RESULTS

A total of 186 patients from 89 cities in 18 provinces in China were enrolled. The median progression-free survival (PFS) was similar among different palbociclib-combined groups ( P  = 0.566): 10.0 months (95% confidence interval [CI] 3.8-16.1) in the +exemestane group, 9.7 months (95% CI 6.3-13.1) in the +letrozole group, 7.8 months (95% CI 5.5-10.2) in the +fulvestrant group, 7.2 months (95% CI 3.2-11.3) in the +toremifene group, and 6.1 months (95% CI 1.2-11.0) in the +anastrozole group. Thirty-four patients (18.3%) had received everolimus for their metastatic disease before the prescription of palbociclib. The disease control rate was significantly lower in patients who had received previous everolimus than in the everolimus-naïve group (50.0% vs . 82.2%, P  < 0.001). Patients pre-treated with everolimus had significantly worse PFS than those in the everolimus-naïve group (3.4 months vs . 8.8 months, P   =  0.001). After propensity score matching, patients pre-treated with everolimus had similar PFS (4.4 months, 95% CI 0.5-8.2) compared with everolimus-naïve patients (6.1 months, 95% CI 4.7-7.5, P   =  0.439).

CONCLUSIONS

Various palbociclib-based regimens have promising efficacy in ER+ metastatic breast cancer in real-world settings, even in patients who had been pre-treated with everolimus.

Pathological Diagnosis, Work-Up and Reporting of Breast Cancer 1st Central-Eastern European Professional Consensus Statement on Breast Cancer

This text is based on the recommendations accepted by the 4th Hungarian Consensus Conference on Breast Cancer, modified on the basis of the international consultation and conference within the frames of the Central-Eastern European Academy of Oncology. The recommendations cover non-operative, intraoperative and postoperative diagnostics, determination of prognostic and predictive markers and the content of cytology and histology reports. Furthermore, they address some specific issues such as the current status of multigene molecular markers, the role of pathologists in clinical trials and prerequisites for their involvement, and some remarks about the future.

The oncogenic PI3K-induced transcriptomic landscape reveals key functions in splicing and gene expression regulation

The PI3K pathway regulates proliferation, survival, and metabolism and is frequently activated across human cancers. A comprehensive elucidation of how this signaling pathway controls transcriptional and co-transcriptional processes could provide new insights into the key functions of PI3K signaling in cancer. Here, we undertook a transcriptomic approach to investigate genome-wide gene expression and transcription factor (TF) activity changes, as well as splicing and isoform usage dynamics, downstream of PI3K. These analyses uncovered widespread alternatively spliced (AS) isoforms linked to proliferation, metabolism, and splicing in PIK3CA mutant cells, which were reversed by inhibition of PI3Kα. Analysis of paired tumor biopsies from PIK3CA-mutated breast cancer patients undergoing treatment with PI3Kα inhibitors identified widespread splicing alterations that affect specific isoforms in common with the preclinical models, and these alterations, namely PTK2/FRNK and AFMID isoforms, were validated as functional drivers of cancer cell growth or migration. Mechanistically, isoform-specific splicing factors mediated PI3K-dependent RNA splicing. Treatment with splicing inhibitors rendered breast cancer cells more sensitive to the PI3Kα inhibitor alpelisib, resulting in greater growth inhibition than alpelisib alone. This study provides the first comprehensive analysis of widespread splicing alterations driven by oncogenic PI3K in breast cancer. The atlas of PI3K-mediated splicing programs establishes a key role for the PI3K pathway in regulating splicing, opening new avenues for exploiting PI3K signaling as a therapeutic vulnerability in breast cancer.

HER2 Mediates PSMA/mGluR1-Driven Resistance to the DS-7423 Dual PI3K/mTOR Inhibitor in PTEN Wild-type Prostate Cancer Models

Prostate cancer remains a major cause of male mortality. Genetic alteration of the PI3K/AKT/mTOR pathway is one of the key events in tumor development and progression in prostate cancer, with inactivation of the PTEN tumor suppressor being very common in this cancer type. Extensive evaluation has been performed on the therapeutic potential of PI3K/AKT/mTOR inhibitors and the resistance mechanisms arising in patients with PTEN-mutant background. However, in patients with a PTEN wild-type phenotype, PI3K/AKT/mTOR inhibitors have not demonstrated efficacy, and this remains an area of clinical unmet need. In this study, we have investigated the response of PTEN wild-type prostate cancer cell lines to the dual PI3K/mTOR inhibitor DS-7423 alone or in combination with HER2 inhibitors or mGluR1 inhibitors. Upon treatment with the dual PI3K/mTOR inhibitor DS-7423, PTEN wild-type prostate cancer CWR22/22RV1 cells upregulate expression of the proteins PSMA, mGluR1, and the tyrosine kinase receptor HER2, while PTEN-mutant LNCaP cells upregulate androgen receptor and HER3. PSMA, mGluR1, and HER2 exert control over one another in a positive feedback loop that allows cells to overcome treatment with DS-7423. Concomitant targeting of PI3K/mTOR with either HER2 or mGluR1 inhibitors results in decreased cell survival and tumor growth in xenograft studies. Our results suggest a novel therapeutic possibility for patients with PTEN wild-type PI3K/AKT-mutant prostate cancer based in the combination of PI3K/mTOR blockade with HER2 or mGluR1 inhibitors.

YTHDF1 upregulation mediates hypoxia-dependent breast cancer growth and metastasis through regulating PKM2 to affect glycolysis

N6-methyladenosine modification is the most common RNA modification mechanism in mammals. YTHDF1, a m⁶A reader, can recognize the m⁶A of mRNAs to facilitate the interaction with the mRNA ribosome assembly and recruitment of translation initiators to promote translation. From a clinical perspective, YTHDF1 upregulation is frequently observed in breast cancer, but its involvement in those cancer-related events is still unclear. Here we report that YTHDF1 is a cancer driver capable of facilitating the proliferation and invasion of breast cancer cells as well as enhancing tumorigenicity and metastasis through promoting glycolysis. We found that tumor hypoxia can transcriptionally induce HIF1α and post-transcriptionally inhibit the expression of miR-16-5p to promote YTHDF1 expression, which could sequentially enhance tumor glycolysis by upregulating PKM2 and eventually increase the tumorigenesis and metastasis potential of breast cancer cells. Inhibiting YTHDF1 via gene knockdown or miR-16-5p would significantly abolish YTHDF1-dependent tumor growth and metastasis. In summary, we identified the role of the YTHDF1-PKM2 signal axis in the occurrence and development of breast cancer, which can be used as a potential target for breast cancer treatment.

Toward Targeted Therapies in Oesophageal Cancers: An Overview

Oesophageal cancer is one of the leading causes of cancer-related death worldwide. Oesophageal cancer occurs as squamous cell carcinoma (ESCC) or adenocarcinoma (EAC). Prognosis for patients with either ESCC or EAC is poor, with less than 20% of patients surviving more than 5 years after diagnosis. A major progress has been made in the development of biomarker-driven targeted therapies against breast and lung cancers, as well as melanoma. However, precision oncology for patients with oesophageal cancer is still virtually non-existent. In this review, we outline the recent advances in oesophageal cancer profiling and clinical trials based on targeted therapies in this disease.

Impact of Duration of Neoadjuvant Aromatase Inhibitors on Molecular Expression Profiles in Estrogen Receptor-positive Breast Cancers

PURPOSE

Aromatase inhibitor (AI) treatment is the standard of care for postmenopausal women with primary estrogen receptor-positive breast cancer. The impact of duration of neoadjuvant endocrine therapy (NET) on molecular characteristics is still unknown. We evaluated and compared changes of gene expression profiles under short-term (2-week) versus longer-term neoadjuvant AIs.

EXPERIMENTAL DESIGN

Global gene expression profiles from the PeriOperative Endocrine Therapy for Individualised Care (POETIC) trial (137 received 2 weeks of AIs and 47 received no treatment) and targeted gene expression from 80 patients with breast cancer treated with NET for more than 1 month (NeoAI) were assessed. Intrinsic subtyping, module scores covering different cancer pathways and immune-related genes were calculated for pretreated and posttreated tumors.

RESULTS

The differences in intrinsic subtypes after NET were comparable between the two cohorts, with most Luminal B (90.0% in the POETIC trial and 76.3% in NeoAI) and 50.0% of HER2 enriched at baseline reclassified as Luminal A or normal-like after NET. Downregulation of proliferative-related pathways was observed after 2 weeks of AIs. However, more changes in genes from cancer-signaling pathways such as MAPK and PI3K/AKT/mTOR and immune response/immune-checkpoint components that were associated with AI-resistant tumors and differential outcome were observed in the NeoAI study.

CONCLUSIONS

Tumor transcriptional profiles undergo bigger changes in response to longer NET. Changes in HER2-enriched and Luminal B subtypes are similar between the two cohorts, thus AI-sensitive intrinsic subtype tumors associated with good survival might be identified after 2 weeks of AI. The changes of immune-checkpoint component expression in early AI resistance and its impact on survival outcome warrants careful investigation in clinical trials.

Minireview: Parabens Exposure and Breast Cancer

There is increasing recognition that environmental exposure to chemicals, such as endocrine-disruptive chemicals (EDCs), contributes to the development of breast cancer. Parabens are a group of EDCs commonly found in personal care products, foods, and pharmaceuticals. Systemic exposure to parabens has been confirmed by the ubiquitous detection of parabens in human blood and urine samples. Although evidence from in vivo and epidemiological studies linking parabens exposure to breast cancer is limited, the current evidence suggests that parabens may negatively interfere with some endocrine and intracrine targets relevant to breast carcinogenesis. So far, most studies have focused on a single paraben's effects and the direct modulating effects on estrogen receptors or the androgen receptor in vitro. Recent studies have revealed that parabens can modulate local estrogen-converting enzymes, 17β-hydroxysteroid dehydrogenase 1 and 2 and increase local estrogen levels. Also, parabens can crosstalk with the human epidermal growth factor receptor 2 (HER2) pathway and work with ER signaling to increase pro-oncogenic c-Myc expression in ER+/HER2+ breast cancer cells. Future studies investigating paraben mixtures and their crosstalk with other EDCs or signaling pathways both in vitro and in vivo in the context of breast cancer development are warranted.