PI3K functions in cancer progression, anticancer immunity and immune evasion by tumors

The roles of cancer stem cells and therapeutic implications in melanoma

Melanoma is a highly malignant skin tumor characterized by high metastasis and poor prognosis. Recent studies have highlighted the pivotal role of melanoma stem cells (MSCs)-a subpopulation of cancer stem cells (CSCs)-in driving tumor growth, metastasis, therapeutic resistance, and recurrence. Similar to CSCs in other cancers, MSCs possess unique characteristics, including specific surface markers, dysregulated signaling pathways, and the ability to thrive within complex tumor microenvironment (TME). This review explored the current landscape of MSC research, discussing the identification of MSC-specific surface markers, the role of key signaling pathways such as Wnt/β-catenin, Notch, and Hedgehog (Hh), and how interactions within the TME, including hypoxia and immune cells, contribute to MSC-mediated drug resistance and metastatic behavior. Furthermore, we also investigated the latest therapeutic strategies targeting MSCs, such as small-molecule inhibitors, immune-based approaches, and novel vaccine developments, with an emphasis on their potential to overcome melanoma progression and improve clinical outcomes. This review aims to provide valuable insights into the complex roles of MSCs in melanoma biology and offers perspectives for future research and therapeutic advances against this challenging disease.

Inhibition of the PI3K/AKT/mTOR pathway in pancreatic cancer: is it a worthwhile endeavor?

Pancreatic cancer (PC) is an aggressive disease that is challenging to treat and is associated with a high mortality rate. The most common type of PC is pancreatic ductal adenocarcinoma (PDAC), and the existing treatment options are insufficient for PDAC patients. Due to the complexity and heterogeneity of PDAC, personalized medicine is necessary for effectively treating this illness. To achieve this, it is essential to understand the mechanism of PDAC carcinogenesis. Targeted therapies are a promising strategy to improve patient outcomes. Aberrant activation of the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway plays a crucial role in PC pathogenesis, from initiation to progression. This review provides a comprehensive overview of the current state of knowledge regarding the PI3K pathway in PDAC, summarizes clinical data on PI3K pathway inhibition in PDAC, and explores potential effective combinations that are a promising direction requiring further investigation in PDAC.

Cellular senescence and metabolic reprogramming: Unraveling the intricate crosstalk in the immunosuppressive tumor microenvironment

The intrinsic oncogenic mechanisms and properties of the tumor microenvironment (TME) have been extensively investigated. Primary features of the TME include metabolic reprogramming, hypoxia, chronic inflammation, and tumor immunosuppression. Previous studies suggest that senescence-associated secretory phenotypes that mediate intercellular information exchange play a role in the dynamic evolution of the TME. Specifically, hypoxic adaptation, metabolic dysregulation, and phenotypic shifts in immune cells regulated by cellular senescence synergistically contribute to the development of an immunosuppressive microenvironment and chronic inflammation, thereby promoting the progression of tumor events. This review provides a comprehensive summary of the processes by which cellular senescence regulates the dynamic evolution of the tumor-adapted TME, with focus on the complex mechanisms underlying the relationship between senescence and changes in the biological functions of tumor cells. The available findings suggest that components of the TME collectively contribute to the progression of tumor events. The potential applications and challenges of targeted cellular senescence-based and combination therapies in clinical settings are further discussed within the context of advancing cellular senescence-related research.

Namodenoson at the Crossroad of Metabolic Dysfunction-Associated Steatohepatitis and Hepatocellular Carcinoma

Namodenoson (CF102) is a small, orally available, anti-inflammatory, and anti-cancer drug candidate currently in phase 2B trial for the treatment of metabolic dysfunction-associated steatohepatitis (MASH; formerly known as non-alcoholic steatohepatitis (NASH)) and in phase 3 pivotal clinical trial for the treatment of hepatocellular carcinoma (HCC). In both MASH and HCC, the mechanism-of-action of namodenoson involves targeting the A3 adenosine receptor (A3AR), resulting in deregulation of downstream signaling pathways and leading to inhibition of inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-8) and stimulation of positive cytokines (G-CSF and adiponectin). Subsequently, inhibition of liver inflammation, steatosis, and fibrosis were documented in MASH experimental models, and inhibition of HCC growth was observed in vitro, in vivo, and in clinical studies. This review discusses the evidence related to the multifaceted mechanism of action of namodenoson, and how this mechanism is reflected in the available clinical data in MASH and HCC.

[Mechanism of propofol-induced apoptosis in neonatal rat oligodendrocytes]

OBJECTIVE

To explore the molecular mechanism of propofol-induced apoptosis in oligodendrocytes.

METHODS

Fortyfive neonatal (7 days old) SD rats were randomized into 3 groups (n=15) for a single intraperitoneal injection of saline (control), long chain fat emulsion, or propofol (50 mg/kg). Eight hours after the injection, the rats were examined for mRNA and protein expressions of caspase-3, caspase-8, and caspase-9 in the brain tissues using qPCR and Western blotting, and the expression levels of nerve growth factor (NGF) mRNA and P-PI3K/P-PAkt were also detected.

RESULTS

Compared with those in the control group, the neonatal rats with propofol injection showed significantly up-regulated mRNA and protein expressions of caspase-3, caspase-8, and caspase-9 in the brain tissue (P<0.05) with significantly down-regulated expressions of NGF mRNA and P-PI3K/P-PAkt (P<0.05).

CONCLUSION

Propofol induces apoptosis in oligodendrocytes by activating the caspase family protein members involved in triggering cell apoptosis and inhibiting the anti-apoptosis mechanism.

Dysregulated Signalling Pathways Driving Anticancer Drug Resistance

One of the leading causes of death worldwide, in both men and women, is cancer. Despite the significant development in therapeutic strategies, the inevitable emergence of drug resistance limits the success and impedes the curative outcome. Intrinsic and acquired resistance are common mechanisms responsible for cancer relapse. Several factors crucially regulate tumourigenesis and resistance, including physical barriers, tumour microenvironment (TME), heterogeneity, genetic and epigenetic alterations, the immune system, tumour burden, growth kinetics and undruggable targets. Moreover, transforming growth factor-beta (TGF-β), Notch, epidermal growth factor receptor (EGFR), integrin-extracellular matrix (ECM), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), wingless-related integration site (Wnt/β-catenin), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and RAS/RAF/mitogen-activated protein kinase (MAPK) signalling pathways are some of the key players that have a pivotal role in drug resistance mechanisms. To guide future cancer treatments and improve results, a deeper comprehension of drug resistance pathways is necessary. This review covers both intrinsic and acquired resistance and gives a comprehensive overview of recent research on mechanisms that enable cancer cells to bypass barriers put up by treatments, and, like "satellite navigation", find alternative routes by which to carry on their "journey" to cancer progression.

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.

Tumor microenvironment and cellular senescence: Understanding therapeutic resistance and harnessing strategies

The tumor microenvironment (TME) is a major contributor to cancer malignancy including development of therapeutic resistance, a process mediated in part through intercellular crosstalk. Besides diverse soluble factors responsible for pro-survival pathway activation, immune evasion and extracellular matrix (ECM) remodeling further promote cancer resistance. Importantly, therapy-induced senescence (TIS) of cells in the TME is frequently observed in anticancer regimens, an off-target effect that can generate profound impacts on disease progression. By conferring the resistance and fueling the repopulation of remaining cancerous cells, TIS is responsible for tumor relapse and distant metastasis in posttreatment stage. This pathological trajectory can be substantially driven by the pro-inflammatory feature of senescent cells, termed as the senescence-associated secretory phenotype (SASP). Targeting strategies to selectively and efficiently remove senescent cells before they exert non-autonomous but largely deleterious effects, are emerging as an effective solution to prevent drug resistance acquired from a treatment-remodeled TME. In this review, we summarize the TME composition and key activities that affect tissue homeostasis and support treatment resistance. Promising opportunities that allow TME-manipulation and senescent cell-targeting (senotherapy) are discussed, with translational pipelines to overcome therapeutic barriers in clinical oncology projected.

Immune Pathway and Gene Database (IMPAGT) Revealed the Immune Dysregulation Dynamics and Overactivation of the PI3K/Akt Pathway in Tumor Buddings of Cervical Cancer

Tumor budding (TB) is a small cluster of malignant cells at the invasive front of a tumor. Despite being an adverse prognosis marker, little research has been conducted on the tumor immune microenvironment of tumor buddings, especially in cervical cancer. Therefore, RNA sequencing was performed using 21 formalin-fixed, paraffin-embedded slides of cervical tissues, and differentially expressed genes (DEGs) were analyzed. Immune Pathway and Gene Database (IMPAGT) was generated for immune profiling. "Pathway in Cancer" was identified as the most enriched pathway for both up- and downregulated DEGs. Kyoto Encyclopedia of Genes and Genomes Mapper and Gene Ontology further revealed the activation of the PI3K/Akt signaling pathway. An IMPAGT analysis revealed immune dysregulation even at the tumor budding stage, especially in the PI3K/Akt/mTOR axis, with a high efficiency and integrity. These findings emphasized the clinical significance of tumor buddings and the necessity of blocking the overactivation of the PI3K/Akt/mTOR pathway to improve targeted therapy in cervical cancer.

Synthesis, Molecular Docking, In Vitro and In Vivo Studies of Novel Dimorpholinoquinazoline-Based Potential Inhibitors of PI3K/Akt/mTOR Pathway

A (series) range of potential dimorpholinoquinazoline-based inhibitors of the PI3K/Akt/mTOR cascade was synthesized. Several compounds exhibited cytotoxicity towards a panel of cancer cell lines in the low and sub-micromolar range. Compound 7c with the highest activity and moderate selectivity towards MCF7 cells which express the mutant type of PI3K was also tested for the ability to inhibit PI3K-(signaling pathway) downstream effectors and associated proteins. Compound 7c inhibited the phosphorylation of Akt, mTOR, and S6K at 125–250 nM. It also triggered PARP1 cleavage, ROS production, and cell death via several mechanisms. Inhibition of PI3Kα was observed at a concentration of 7b 50 µM and of 7c 500 µM and higher, that can indicate minority PI3Kα as a target among other kinases in the titled cascade for 7c. In vivo studies demonstrated an inhibition of tumor growth in the colorectal tumor model. According to the docking studies, the replacement of the triazine core in gedatolisib (8) by a quinazoline fragment, and incorporation of a (hetero)aromatic unit connected with the carbamide group via a flexible spacer, can result in more selective inhibition of the PI3Kα isoform.

Ferroptosis-related lncRNAs signature to predict the survival and immune evasion for lung squamous cell carcinoma

Introduction: the investigation on the interactions between ferroptosis and lncRNAs for lung squamous cell carcinoma (LUSC) has been scare, and its impact on tumor immune microenvironment remained unknown. We aim to not only identify a ferroptosis-related lncRNAs signature for LUSC prognosis, but also evaluate its correlation to tumor immune evasion.

Methods: RNA sequencing data and survival information were obtained from The Cancer Genome Atlas database. A ferroptosis-related lncRNAs signature (FerRLSig) was developed and validated by univariate Cox regression, Least Absolute Shrinkage and Selection Operator regression and multivariate Cox regression. The tumor immune microenvironment and immune evasion were subsequently evaluated based on the FerRLSig stratification.

Results: the FerRLSig consisted of 10 ferroptosis-related lncRNAs and significantly associated with overall survival with satisfactory area under curve (HR = 2.240, 95% CI: 1.845–2.720, p < 0.001, 5-years AUC: 0.756). Based on the FerRLSig stratification, the high-risk group demonstrated not only significantly higher immune infiltration, but also more profound T cell dysfunction and immune evasion, which might ultimately lead to the resistance to current immune checkpoint inhibitors.

Conclusion: a robust prognostic FerRLSig for LUSC has been developed and validated, demonstrating a close association not only with tumor immune cell infiltration, but also with T cell dysfunction and immune evasion. Further investigation is warranted to better improve the survival of LUSC patients based on the FerRLSig stratification.

Identification of Key Pathways and Genes Related to Immunotherapy Resistance of LUAD Based on WGCNA Analysis

Immunotherapy resistance is a major barrier in the application of immune checkpoint inhibitors (ICI) in lung adenocarcinoma (LUAD) patients. Although recent studies have found several mechanisms and potential genes responsible for immunotherapy resistance, ways to solve this problem are still lacking. Tumor immune dysfunction and exclusion (TIDE) algorithm is a newly developed method to calculate potential regulators and indicators of ICI resistance. In this article, we combined TIDE and weighted gene co-expression network analysis (WGCNA) to screen potential modules and hub genes that are highly associated with immunotherapy resistance using the Cancer Genome Atlas (TCGA) dataset of LUAD patients. We identified 45 gene co-expression modules, and the pink module was most correlated with TIDE score and other immunosuppressive features. After considering the potential factors in immunotherapy resistance, we found that the pink module was also highly related to cancer stemness. Further analysis showed enriched immunosuppressive cells in the extracellular matrix (ECM), immunotherapy resistance indicators, and common cancer-related signaling pathways in the pink module. Seven hub genes in the pink module were shown to be significantly upregulated in tumor tissues compared with normal lung tissue, and were related to poor survival of LUAD patients. Among them, THY1 was the gene most associated with TIDE score, a gene highly related to suppressive immune states, and was shown to be strongly expressed in late-stage patients. Immunohistochemistry (IHC) results demonstrated that THY1 level was higher in the progressive disease (PD) group of LUAD patients receiving a PD-1 monoclonal antibody (mAb) and positively correlated with SOX9. Collectively, we identified that THY1 could be a critical biomarker in predicting ICI efficiency and a potential target for avoiding tumor immunotherapy resistance.

PI3K Isoforms in CD8+ T Cell Development and Function

CD8⁺ T cells are an essential part of the immune system and play a vital role in defending against tumors and infections. The phosphoinositide-3-kinase (PI3K), especially class I, is involved in numerous interrelated signaling pathways which control CD8⁺ T cell development, maturation, migration, activation, and differentiation. While CD8⁺ T lymphocytes express all class I PI3K isoforms (PI3Kα, PI3Kβ, PI3Kδ, and PI3Kγ), isoform-specific functions, especially for PI3Kα and PI3Kβ have not been fully elucidated. A few studies suggest the important role of p110δ and p110γ in CD8⁺ T cell activation, signaling, chemotaxis and function and several clinical trials are currently testing the effect of isoform-specific inhibitors in various types of cancers, including Indolent Non-Hodgkin Lymphoma, Peripheral T cell Lymphoma, Chronic Lymphocytic Leukemia, Small Lymphocytic Lymphoma, non-small cell lung carcinoma (NSCLC), head & neck cancer, and breast cancer. This chapter summarizes current knowledge of the roles of various PI3K isoforms and downstream signaling pathways in regulating CD8⁺ T cell fate, including cell proliferation, migration, and memory generation. We also discuss certain clinical trials employing PI3K inhibitors for cancer therapy, their limitations, and future perspectives.

Role of Tumor Microenvironment in Cancer Stem Cells Resistance to Radiotherapy

Cancer is a chronic disorder that involves several elements of both the tumor and the host stromal cells. At present, the complex relationship between the various factors presents in the tumor microenvironment (TME) and tumor cells, as well as immune cells located within the TME, is still poorly known. Within the TME, the crosstalk of these factors and immune cells essentially determines how a tumor reacts to the treatment and how the tumor can ultimately be destroyed, remain dormant, or develop and metastasize. Also, in TME, reciprocal crosstalk between cancer-associated fibroblasts (CAFs), extracellular matrix (ECM), hypoxia-inducible factor (HIF) intensifies the proliferation capacity of cancer stem cells (CSCs). CSCs are subpopulation of cells that reside within the tumor bulk and have the capacity to self-renew, differentiate, and repair DNA damage. These characteristics make CSCs develop resistance to a variety of treatments, such as radiotherapy (RT). RT is a frequent and often curative treatment for local cancer which mediates tumor elimination by cytotoxic actions. Also, cytokines and growth factors that are released into TME, have been involved in the activation of tumor radioresistance and the induction of different immune cells, altering local immune responses. In this review, we discuss the pivotal role of TME in resistance of CSCs to RT.

Resistance of B-Cell Lymphomas to CAR T-Cell Therapy Is Associated With Genomic Tumor Changes Which Can Result in Transdifferentiation

Despite the impressive efficacy of chimeric antigen receptor (CAR) T-cell therapy (CART) in B-cell non-Hodgkin lymphomas, durable responses are uncommon. The histopathologic and molecular features associated with treatment failure are still largely unknown. Therefore, we have analyzed 19 sequential tumor samples from 9 patients, prior anti-CD19 CART (pre-CART) and at relapse (post-CART), using immunohistochemistry, fluorescence in situ hybridization, array comparative genomic hybridization, next-generation DNA and RNA sequencing, and genome-scale DNA methylation. The initial diagnosis was diffuse large B-cell lymphoma (n=6), double-hit high-grade B-cell lymphoma (n=1), and Burkitt lymphoma (n=2). Histopathologic features were mostly retained at relapse in 7/9 patients, except the frequent loss of 1 or several B-cell markers. The remaining 2 cases (1 diffuse large B-cell lymphoma and 1 Burkitt lymphoma) displayed a dramatic phenotypic shift in post-CART tumors, with the drastic downfall of B-cell markers and emergence of T-cell or histiocytic markers, despite the persistence of identical clonal immunoglobulin gene rearrangements. The post-CART tumor with aberrant T-cell phenotype showed reduced mRNA expression of most B-cell genes with increased methylation of their promoter. Fluorescence in situ hybridization and comparative genomic hybridization showed global stability of chromosomal alterations in all paired samples, including 17p/TP53 deletions. New pathogenic variants acquired in post-CART samples included mutations triggering the PI3K pathway (PIK3R1, PIK3R2, PIK3C2G) or associated with tumor aggressiveness (KRAS, INPP4B, SF3B1, SYNE1, TBL1XR1). These results indicate that CART-resistant B-cell non-Hodgkin lymphomas display genetic remodeling, which may result in profound dysregulation of B-cell differentiation. Acquired mutations in the PI3K and KRAS pathways suggest that some targeted therapies could be useful to overcome CART resistance.

Correlation of PIK3CA mutation with programmed death ligand-1 (PD-L1) expression and their clinicopathological significance in colorectal cancer

Background

The prognostic significance of PIK3CA mutations in colorectal cancer (CRC) remains controversial. Recently, an association between programmed death ligand-1 (PD-L1) and PIK3CA mutations has been reported. The study presented here was conducted to investigate the effect of PIK3CA mutations on the prognosis of CRC patients and the association between PIK3CA mutations and PD-L1.

Methods

PIK3CA mutations were analyzed by targeted next-generation sequencing using formalin-fixed paraffin-embedded specimens from 224 primary CRC patients. PD-L1 expression was evaluated by immunohistochemical staining.

Results

PIK3CA mutations and PD-L1 expression were detected in 21.4% and 10.3% of CRC patients, respectively. PIK3CA mutations were significantly correlated with right-side colon cancer (P=0.011) and were correlated inversely with lymph node metastasis (P=0.026), distant metastasis (P=0.047), and high TNM stage (P=0.036). In univariate analysis, PIK3CA mutations were correlated with longer relapse-free survival in CRC patients. PD-L1 expression was correlated significantly with PIK3CA mutations (P<0.001).

Conclusions

PIK3CA mutations were associated with favorable prognostic factors, longer relapse-free survival, and expression of PD-L1. Further investigation is needed to identify whether PIK3CA mutations are a good prognostic factor. Additionally, further studies are needed to understand the mechanisms behind the correlation between PIK3CA mutations and PD-L1 expression.

Transcending toward Advanced 3D-Cell Culture Modalities: A Review about an Emerging Paradigm in Translational Oncology

Cancer is a disorder characterized by an uncontrollable overgrowth and a fast-moving spread of cells from a localized tissue to multiple organs of the body, reaching a metastatic state. Throughout years, complexity of cancer progression and invasion, high prevalence and incidence, as well as the high rise in treatment failure cases leading to a poor patient prognosis accounted for continuous experimental investigations on animals and cellular models, mainly with 2D- and 3D-cell culture. Nowadays, these research models are considered a main asset to reflect the physiological events in many cancer types in terms of cellular characteristics and features, replication and metastatic mechanisms, metabolic pathways, biomarkers expression, and chemotherapeutic agent resistance. In practice, based on research perspective and hypothesis, scientists aim to choose the best model to approach their understanding and to prove their hypothesis. Recently, 3D-cell models are seen to be highly incorporated as a crucial tool for reflecting the true cancer cell microenvironment in pharmacokinetic and pharmacodynamics studies, in addition to the intensity of anticancer drug response in pharmacogenomics trials. Hence, in this review, we shed light on the unique characteristics of 3D cells favoring its promising usage through a comparative approach with other research models, specifically 2D-cell culture. Plus, we will discuss the importance of 3D models as a direct reflector of the intrinsic cancer cell environment with the newest multiple methods and types available for 3D-cells implementation.

Aspects of the Tumor Microenvironment Involved in Immune Resistance and Drug Resistance

The tumor microenvironment (TME) is a complex and ever-changing "rogue organ" composed of its own blood supply, lymphatic and nervous systems, stroma, immune cells and extracellular matrix (ECM). These complex components, utilizing both benign and malignant cells, nurture the harsh, immunosuppressive and nutrient-deficient environment necessary for tumor cell growth, proliferation and phenotypic flexibility and variation. An important aspect of the TME is cellular crosstalk and cell-to-ECM communication. This interaction induces the release of soluble factors responsible for immune evasion and ECM remodeling, which further contribute to therapy resistance. Other aspects are the presence of exosomes contributed by both malignant and benign cells, circulating deregulated microRNAs and TME-specific metabolic patterns which further potentiate the progression and/or resistance to therapy. In addition to biochemical signaling, specific TME characteristics such as the hypoxic environment, metabolic derangements, and abnormal mechanical forces have been implicated in the development of treatment resistance. In this review, we will provide an overview of tumor microenvironmental composition, structure, and features that influence immune suppression and contribute to treatment resistance.

Targeting the crosstalk between canonical Wnt/β-catenin and inflammatory signaling cascades: A novel strategy for cancer prevention and therapy

Emerging scientific evidence indicates that inflammation is a critical component of tumor promotion and progression. Most cancers originate from sites of chronic irritation, infections and inflammation, underscoring that the tumor microenvironment is largely orchestrated by inflammatory cells and pro-inflammatory molecules. These inflammatory components are intimately involved in neoplastic processes which foster proliferation, survival, invasion, and migration, making inflammation the primary target for cancer prevention and treatment. The influence of inflammation and the immune system on the progression and development of cancer has recently gained immense interest. The Wnt/β-catenin signaling pathway, an evolutionarily conserved signaling strategy, has a critical role in regulating tissue development. It has been implicated as a major player in cancer development and progression with its regulatory role on inflammatory cascades. Many naturally-occurring and small synthetic molecules endowed with inherent anti-inflammatory properties inhibit this aberrant signaling pathway, making them a promising class of compounds in the fight against inflammatory cancers. This article analyzes available scientific evidence and suggests a crosslink between Wnt/β-catenin signaling and inflammatory pathways in inflammatory cancers, especially breast, gastrointestinal, endometrial, and ovarian cancer. We also highlight emerging experimental findings that numerous anti-inflammatory synthetic and natural compounds target the crosslink between Wnt/β-catenin pathway and inflammatory cascades to achieve cancer prevention and intervention. Current challenges, limitations, and future directions of research are also discussed.

Five Circular RNAs in Metabolism Pathways Related to Prostate Cancer

Prostate cancer (PCa) is the most common malignant tumor in men, and its incidence increases with age. Serum prostate-specific antigen and tissue biopsy remain the standard for diagnosis of suspected PCa. However, these clinical indicators may lead to aggressive overtreatment in patients who have been treated sufficiently with active surveillance. Circular RNAs (circRNAs) have been recently recognized as a new type of regulatory RNA that is not easily degraded by RNases and other exonucleases because of their covalent closed cyclic structure. Thus, we utilized high-throughput sequencing data and bioinformatics analysis to identify specifically expressed circRNAs in PCa and filtered out five specific circRNAs for further analysis—hsa_circ_0006410, hsa_circ_0003970, hsa_circ_0006754, hsa_circ_0005848, and a novel circRNA, hsa_circ_AKAP7. We constructed a circRNA-miRNA regulatory network and used miRNA and differentially expressed mRNA interactions to predict the function of the selected circRNAs. Furthermore, survival analysis of their cognate genes and PCR verification of these five circRNAs revealed that they are closely related to well-known PCa pathways such as the MAPK signaling pathway, P53 pathway, androgen receptor signaling pathway, cell cycle, hormone-mediated signaling pathway, and cellular lipid metabolic process. By understanding the related metabolism of circRNAs, these circRNAs could act as metabolic biomarkers, and monitoring their levels could help diagnose PCa. Meanwhile, the exact regulatory mechanism for AR-related regulation in PCa is still unclear. The circRNAs we found can provide new solutions for research in this field.

Identification of molecular features correlating with tumor immunity in gastric cancer by multi-omics data analysis

Background

Although immunotherapy has achieved success in treating various refractory malignancies including gastric cancers (GCs) with DNA mismatch repair deficiency, only a subset of cancer patients are responsive to immunotherapy. Therefore, the identification of useful biomarkers or interventional targets for improving cancer immunotherapy response is urgently needed.

Methods

We investigated the associations between various molecular features and immune signatures using three multi-omics GC datasets. These molecular features included genes, microRNAs (miRNAs), long non-coding RNAs (lncRNAs), proteins, and pathways, and the immune signatures included CD8+ T cell infiltration, immune cytolytic activity (ICA), and PD-L1 expression. Moreover, we investigated the association between gene mutations and survival prognosis in a gastrointestinal (GI) cancer cohort receiving immunotherapy and two GC cohorts not receiving such a therapy.

Results

The mutations of some important oncogenes and tumor suppressor genes were appreciably associated with immune signatures in GC, including PIK3CA, MTOR, RNF213, TP53, ARID1A, PTEN, ATM, and CDH1. Moreover, a number of genes exhibited a significant expression correlation with immune signatures in GC, including CXCL9, CXCL13, CXCR6, CCL5, GUCY2C, MAP3K9, NEK3, PAK6, STK35, and WNK2. We identified several proteins whose expression had a significant positive correlation with immune signatures in GC. These proteins included caspase-7, PI3K-p85, PREX1, Lck, Bcl-2, and transglutaminase. In contrast, acetyl-CoA carboxylase (ACC) had a significant inverse expression correlation with immune signatures in GC, suggesting that inhibiting ACC could enhance antitumor immunity in GC. Furthermore, we identified numerous miRNAs and lncRNAs with a significant expression correlation with GC immunity, including hsa-miR-150, 155, 142, 342, 146, 101, 511, 29, AC022706.1, LINC01871, and AC006033.2. We also identified numerous cancer-associated pathways whose activity was associated with GC immunity, including mTOR, PI3K-AKT, MAPK, HIF-1, and VEGF signaling pathways. Interestingly, we found seven genes (ARID1A, BCOR, MTOR, CREBBP, SPEN, NOTCH4, and TET1) whose mutations were associated with better OS in GI cancer patients receiving anti-PD-1/PD-L1 immunotherapy but were not associated with OS in GC patients without immunotherapy.

Conclusions

The molecular features significantly associated with GC immunity could be useful biomarkers for stratifying GC patients responsive to immunotherapy or intervention targets for promoting antitumor immunity and immunotherapy response in GC.

Vitamin C: A stem cell promoter in cancer metastasis and immunotherapy

Vitamin C is an electron donor and is involved in a variety of biochemical reactions in stem cell and cancer stem cell, as well as collagen synthesis and the regulation of hypoxia-inducible factor synthesis, which two affect extracellular matrix remodelling and hence cancer metastasis. Specific doses of vitamin C can stop cancer cell glycolysis and block nitroso synthesis, indicating the potential of vitamin C in cancer treatment. Recent studies preliminary revealed Vitamin C enhance the cancer's immune response to anti PD-L1 therapy through multiple indirect approaches. Herein we reviewed the recent function of vitamin C for further research in sequential aspects of cancer stem cell, extracellular matrix remodeling, cancer metastasis and cancer immunotherapy.

Design and Development of Novel Urea, Sulfonyltriurea, and Sulfonamide Derivatives as Potential Inhibitors of phingosine Kinase 1

Sphingosine kinase 1 (SphK1) is one of the well-studied drug targets for cancer and inflammatory diseases. Recently discovered small-molecule inhibitors of SphK1 have been recommended in cancer therapeutics; however, selectivity and potency of first-generation inhibitors are great challenge. In search of effective SphK1 inhibitors, a set of small molecules have been designed and synthesized bearing urea, sulfonylurea, sulfonamide, and sulfonyltriurea groups. The binding affinity of these inhibitors was measured by fluorescence-binding assay and isothermal titration calorimetry. Compounds 1, 5, 6, and 7 showed an admirable binding affinity to the SphK1 in the sub-micromolar range and significantly inhibited SphK1 activity with admirable IC50 values. Molecular docking studies revealed that these compounds fit well into the sphingosine binding pocket of SphK1 and formed significant number of hydrogen bonds and van der Waals interactions. These molecules may be exploited as potent and selective inhibitors of SphK1 that could be implicated in cancer therapeutics after the required in vivo validation.

Analysis of DNA methylation patterns in the tumor immune microenvironment of metastatic melanoma

The presence of immune cells in the tumor microenvironment has been associated with response to immunotherapies across several cancer types, including melanoma. Despite its therapeutic relevance, characterization of the melanoma immune microenvironments remains insufficiently explored. To distinguish the immune microenvironment in a cohort of 180 metastatic melanoma clinical specimens, we developed a method using promoter CpG methylation of immune cell type-specific genes extracted from genome-wide methylation arrays. Unsupervised clustering identified three immune methylation clusters with varying levels of immune CpG methylation that are related to patient survival. Matching protein and gene expression data further corroborated the identified epigenetic characterization. Exploration of the possible immune exclusion mechanisms at play revealed likely dependency on MITF protein level and PTEN loss-of-function events for melanomas unresponsive to immunotherapies (immune-low). To understand whether melanoma tumors resemble other solid tumors in terms of immune methylation characteristics, we explored 15 different solid tumor cohorts from TCGA. Low-dimensional projection based on immune cell type-specific methylation revealed grouping of the solid tumors in line with melanoma immune methylation clusters rather than tumor types. Association of survival outcome with immune cell type-specific methylation differed across tumor and cell types. However, in melanomas immune cell type-specific methylation was associated with inferior patient survival. Exploration of the immune methylation patterns in a pan-cancer context suggested that specific immune microenvironments might occur across the cancer spectrum. Together, our findings underscore the existence of diverse immune microenvironments, which may be informative for future immunotherapeutic applications.

Pretargeted delivery of PI3K/mTOR small-molecule inhibitor-loaded nanoparticles for treatment of non-Hodgkin's lymphoma

Overactivation of the PI3K/mTOR signaling has been identified in non-Hodgkin's lymphoma. BEZ235 is an effective dual PI3K/mTOR inhibitor, but it was withdrawn from early-phase clinical trials owing to poor solubility and on-target/off-tumor toxicity. Here, we developed a nanoparticle (NP)-based pretargeted system for the therapeutic delivery of BEZ235 to CD20- and HLA-DR-expressing lymphoma cells for targeted therapy. The pretargeted system is composed of dibenzocyclooctyne-functionalized anti-CD20 and anti-Lym1 antibodies as the tumor-targeting components and azide-functionalized BEZ235-encapsulated NPs as the effector drug carrier. Using lymphoma cell lines with different CD20 and HLA-DR antigen densities as examples, we demonstrate that the dual antibody pretargeted strategy effectively raises the number of NPs retained on the target tumor cells and improves the in vitro and in vivo antitumor activity of BEZ235 through the inhibition of the PI3K/mTOR pathway. Our data demonstrate that the NP-based pretargeted system improves the therapeutic window of small-molecule kinase inhibitor.

High PD-L1 expression in gastric cancer (GC) patients and correlation with molecular features

BACKGROUND

The programmed death receptor ligand 1 (PD-L1) immunohistochemistry (IHC) 22C3 pharmDx assay is a widely used selection method for pembrolizumab treatment in gastric cancer (GC) patients, especially in the U.S. The present study investigated the relationship between PD-L1 expression and the clinical features, molecular markers, and molecular subtypes of GC.

METHODS

PD-L1 expression was assessed based on combined positive score (CPS) using PD-L1 IHC 22C3 pharmDx in the Asian Cancer Research Group (ACRG) GC cohort (N = 300), which has been previously genomically profiled. PD-L1 positivity was defined as PD-L1 CPS ≥ 1. The association between PD-L1 expression and clinical features, tumor burden, and molecular subtypes (ACRG and The Cancer Genome Atlas [TCGA]) was analyzed.

RESULTS

Of the 300 tumors, 178 (59.3 %) had PD-L1 CPS ≥ 1 and 122 (40.7 %) had PD-L1 CPS < 1. PD-L1 CPS ≥ 1 was significantly associated with stage I tumor (P = 0.022), high microsatellite instability (MSI-H) (P < 0.001), Epstein-Barr virus (EBV) positivity (P = 0.008), and positive Helicobacter pylori status (P = 0.001). PD-L1 CPS ≥ 1 was observed in 96/193 (49.7 %) EBV-negative/microsatellite stable (MSS) tumors. In gene expression profiling, PD-L1 CPS was highly correlated with mutational load (P < 0.001) as well as EBV (P < 0.001) and MSI subtypes (P < 0.001); 27/300 (9%) GC patients had a very high PD-L1 (≥ 20) score (MSI-H, n = 10; EBV, n = 6; and non-EBV/MSS, n = 11). OS was longer in patients with PD-L1 CPS ≥ 1 tumors than in those with PD-L1 CPS < 1 tumors (median OS not reached vs. 40 months; P = 0.008; log-rank test).

CONCLUSIONS

PD-L1 is expressed in 59.3 % of GC patients and is associated with MSI and EBV positivity. These results provide a basis for identifying GC patients who may benefit from anti-PD-1/PD-L1 therapy.

Response of metastatic mouse invasive lobular carcinoma to mTOR inhibition is partly mediated by the adaptive immune system

Effective treatment of invasive lobular carcinoma (ILC) of the breast is hampered by late detection, invasive growth, distant metastasis, and poor response to chemotherapy. Phosphoinositide 3-kinase (PI3K) signaling, one of the major druggable oncogenic signaling networks, is frequently activated in ILC. We investigated treatment response and resistance to AZD8055, an inhibitor of mammalian target of rapamycin (mTOR), in the K14-cre;Cdh1^Flox/Flox;Trp53^Flox/Flox (KEP) mouse model of metastatic ILC. Inhibition of mTOR signaling blocked the growth of primary KEP tumors as well as the progression of metastatic disease. However, primary tumors and distant metastases eventually acquired resistance after long-term AZD8055 treatment, despite continued effective suppression of mTOR signaling in cancer cells. Interestingly, therapeutic responses were associated with increased expression of genes related to antigen presentation. Consistent with this observation, increased numbers of tumor-infiltrating major histocompatibility complex class II-positive (MHCII+) immune cells were observed in treatment-responsive KEP tumors. Acquisition of treatment resistance was associated with loss of MHCII+ cells and reduced expression of genes related to the adaptive immune system. The therapeutic efficacy of mTOR inhibition was reduced in Rag1^−/- mice lacking mature T and B lymphocytes, compared to immunocompetent mice. Furthermore, therapy responsiveness could be partially rescued by transplanting AZD8055-resistant KEP tumors into treatment-naïve immunocompetent hosts. Collectively, these data indicate that the PI3K signaling pathway is an attractive therapeutic target in invasive lobular carcinoma, and that part of the therapeutic effect of mTOR inhibition is mediated by the adaptive immune system.

Programmed necrosis and its role in management of breast cancer

Breast cancer is one of the major causes of cancer related deaths in women worldwide. A major factor responsible for treatment failure in breast cancer is the development of resistance to commonly used chemotherapeutic drugs leading to disease relapse. Several studies have shown dysregulation of molecular machinery of apoptosis, the major programmed cell death pathway in breast malignancies. Thus, there is an unmet need to search for an alternative cell death pathway which can work when apoptosis is compromised. Necroptosis or programmed necrosis is a relatively recently described entity which has attracted attention in this context. Classically, even in physiological conditions necroptosis is found to act if apoptosis is not functional due to some reason. Recently, more and more studies are being conducted in different malignancies to explore the possibility and utility of inducing cell death by necroptosis. The present review describes the key molecular players involved in necroptotic pathway and their status in breast cancer. In addition, the research done to utilize this pathway for treatment of breast cancer has also been highlighted.

The Role of the Extracellular Matrix in Cancer Stemness

As our understanding of cancer cell biology progresses, it has become clear that tumors are a heterogenous mixture of different cell populations, some of which contain so called "cancer stem cells" (CSCs). Hallmarks of CSCs include self-renewing capability, tumor-initiating capacity and chemoresistance. The extracellular matrix (ECM), a major structural component of the tumor microenvironment, is a highly dynamic structure and increasing evidence suggests that ECM proteins establish a physical and biochemical niche for CSCs. In cancer, abnormal ECM dynamics occur due to disrupted balance between ECM synthesis and secretion and altered expression of matrix-remodeling enzymes. Tumor-derived ECM is biochemically distinct in its composition and is stiffer compared to normal ECM. In this review, we will provide a brief overview of how different components of the ECM modulate CSC properties then discuss how physical, mechanical, and biochemical cues from the ECM drive cancer stemness. Given the fact that current CSC targeting therapies face many challenges, a better understanding of CSC-ECM interactions will be crucial to identify more effective therapeutic strategies to eliminate CSCs.

PI3K-AKT-mTOR and NFκB Pathways in Ovarian Cancer: Implications for Targeted Therapeutics

Ovarian cancer is the most lethal gynecologic malignancy in the United States, with an estimated 22,530 new cases and 13,980 deaths in 2019. Recent studies have indicated that the phosphoinositol 3 kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), as well as the nuclear factor-κ light chain enhancer of activated B cells (NFκB) pathways are highly mutated and/or hyper-activated in a majority of ovarian cancer patients, and are associated with advanced grade and stage disease and poor prognosis. In this review, we will investigate PI3K/AKT/mTOR and their interconnection with NFκB pathway in ovarian cancer cells.

Mutations Defining Patient Cohorts With Elevated PD-L1 Expression in Gastric Cancer

The immunotherapy agent pembrolizumab has been approved for gastric cancer (GC) patients with recurrent or advanced disease who are PD-L1 positive. Mutations in the primary lesion may drive the expression of immune targets thereby priming the tumor to therapeutic sensitivity. In this study, we aimed to uncover mutations associated with elevated PD-L1 expression in GC patients. Data from 410 GC patients were available, including the mutational spectrum of 39,916 genes and expression values of 20,500 genes. PD-L1 gene expression was compared to the mutational status of each gene separately by using a Mann-Whitney U-test and a Receiver Operating Characteristic test. Only mutations with a prevalence over 5% were considered. Significance was accepted in cases of p < 1E-05 and a fold change over 1.44. Mutations in 209 genes were associated with increased PD-L1 expression. These mutations were enriched in genes related to microtubule-based movement (p = 3.4E-4), cell adhesion (p = 4.9E-4), response to DNA-damage (p = 6.9E-4), and double-strand break-repair (p = 1.6E-3). Mutations in TTK (p = 8.8E-10, AUC = 0.77), COL7A1 (p = 2.0E-9, AUC = 0.74), KIF15 (p = 2.5E-9, AUC = 0.75), and BDP1 (p = 3.3E-9, AUC = 0.74) had the strongest link to elevated PD-L1 expression. Finally, we established a decision tree based on mutations in PIK3CA, MEF2C, SLC11A1, and KIF15 capable to separate patient sub-cohorts with elevated PD-L1 expression. In summary, we identified mutations associated with elevated PD-L1 expression that facilitate the development of better prognostic biomarkers for GC, and might offer insight into the underlying tumor biology.

Oncosuppressors and Oncogenes: Role in Haemangioma Genesis and Potential for Therapeutic Targeting

Genetic lesions in proto-oncogenes result in the perturbation of angiogenesis, the formation of neovessels from a pre-existing microvasculature. Similarly, the subversion of tumor suppressor genes promotes tumor vascularization. Excessive neovessel formation is associated with various neoplasms such as infantile hemangiomas (IH). Hemangiomas are the most common tumors in pediatric patients and at present have no definitive treatment. The pathogenesis of IH is not well understood; however, both vasculogenesis and angiogenesis are associated with hemangioma genesis. A number of factors that modulate angiogenesis and vasculogenesis have been shown to be dysregulated in IH. Several of the oncogenes and tumor suppressors linked to the promotion of angiogenesis are also altered in infantile hemangioma. In this review, the roles of oncogenes and tumor suppressor genes during neovascularization and hemangioma genesis are explored. In addition, the potential for targeting these genes in IH therapy is discussed.

The effect of chemotherapy on programmed cell death 1/programmed cell death 1 ligand axis: some chemotherapeutical drugs may finally work through immune response

Most tumors are immunogenic which would trigger some immune response. Chemotherapy also has immune potentiating mechanisms of action. But it is unknown whether the immune response is associated with the efficacy of chemotherapy and the development of chemoresistance. Recently, there is a growing interest in immunotherapy, among which the co-inhibitory molecules, programmed cell death 1/programmed cell death 1 ligand (PD-1/PD-L1) leads to immune evasion. Since some reports showed that conventional chemotherapeutics can induce the expression of PD-L1, we try to summarize the effect of chemotherapy on PD-1/PD-L1 axis and some potential molecules relevant to PD-1/PD-L1 in chemoresistance in this review.

Inhibition of Phosphorylated c-Jun NH(2)-terminal Kinase by 2',4'-dihydroxy-6-methoxy-3,5-dimethylchalcone Isolated from Eugenia aquea Burm f. Leaves in Jurkat T-cells

Background:

Indonesian medicinal plants have been used for their anticancer activity for decades. However, the therapeutic effects of medicinal plants have not been fully examined scientifically. As cancer is a major health problem worldwide, searching for a new anticancer compound has attracted considerable attention. Our previous study found that 2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone, an active compound isolated from leaves of Indonesian medicinal plants Eugenia aquea Burm f. (Myrtaceae), had anticancer activity in MCF-7 human breast cancer cells through induction of apoptosis.

Objective:

To investigate the molecular mechanism of 2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone antiproliferative activity.

Materials and Methods:

Leaves of E. aquea were extracted by ethanol, fractionated by ethyl acetate, n-hexane, or water, and isolated for its active compound. Jurkat T-cells were treated with 2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone for 12 and 24 h, and a cell viability assay and real-time-reverse transcriptase polymerase chain reaction for interleukin-2 (IL-2) mRNA measurement were performed. The effects of active compound to mitogen-activated protein kinases were also examined to investigate the mechanism of its antiproliferative activity.

Results:

2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone inhibited Jurkat T-cell proliferation with a half maximal inhibitory concentration of 59.5 mM. Although IL-2 mRNA expression was slightly increased after treatment, it inhibited c-Jun N-terminal kinase expression but not p38 and extracellular signal-regulated kinase expression.

Conclusions:

Our study indicated that the molecular mechanism mediating the antiproliferative activity of 2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone may be attributed to the stimulation of an immunological microenvironment in the cells.

SUMMARY

2’,4’-dihydroxy-6-methoxy-3,5-dimethylchalcone was isolated from Eugenia aquea. The antiproliferative activity of 2’,4’-dihydroxy-6- methoxy-3,5-dimethylchalcone significantly showed in Jurkat T-cells with a half maximal inhibitory concentration of 59.5 mM through inhibition of c-Jun N-terminal kinase phosphorylation. Interleukin-2 mRNA expression was also slightly increased after treatment with the compound, and this result may be indicated to the stimulation of the immunological microenvironment in T-cells.

Abbreviations used:E. aquea: Eugenia aquea, IL-2: Interleukin-2, MAPK: Mitogen-activated protein kinase, ERKs: Extracellular signal-regulated kinases, JNKs: c-Jun N-terminal kinases, p38: p38 MAPK, PI3K: Phosphatidylinositol-3 kinase, IC₅₀: Half maximal inhibitory concentration.

hrHPV E5 oncoprotein: immune evasion and related immunotherapies

The immune response is a key factor in the fight against HPV infection and related cancers, and thus, HPV is able to promote immune evasion through the expression of oncogenes. In particular, the E5 oncogene is responsible for modulation of several immune mechanisms, including antigen presentation and inflammatory pathways. Moreover, E5 was suggested as a promising therapeutic target, since there is still no effective medical therapy for the treatment of HPV-related pre-neoplasia and cancer. Indeed, several studies have shown good prospective for E5 immunotherapy, suggesting that it could be applied for the treatment of pre-cancerous lesions. Thus, insofar as the majority of cervical, oropharyngeal and anal cancers are caused by high-risk HPV (hrHPV), mainly by HPV16, the aim of this review is to discuss the immune pathways interfered by E5 oncoprotein of hrHPV highlighting the various aspects of the potential immunotherapeutic approaches.

Stratification of clear cell renal cell carcinoma (ccRCC) genomes by gene-directed copy number alteration (CNA) analysis

Tumorigenic processes are understood to be driven by epi-/genetic and genomic alterations from single point mutations to chromosomal alterations such as insertions and deletions of nucleotides up to gains and losses of large chromosomal fragments including products of chromosomal rearrangements e.g. fusion genes and proteins. Overall comparisons of copy number alterations (CNAs) presented in 48 clear cell renal cell carcinoma (ccRCC) genomes resulted in ratios of gene losses versus gene gains between 26 ccRCC Fuhrman malignancy grades G1 (ratio 1.25) and 20 G3 (ratio 0.58). Gene losses and gains of 15762 CNA genes were mapped to 795 chromosomal cytoband loci including 280 KEGG pathways. CNAs were classified according to their contribution to Fuhrman tumour gradings G1 and G3. Gene gains and losses turned out to be highly structured processes in ccRCC genomes enabling the subclassification and stratification of ccRCC tumours in a genome-wide manner. CNAs of ccRCC seem to start with common tumour related gene losses flanked by CNAs specifying Fuhrman grade G1 losses and CNA gains favouring grade G3 tumours. The appearance of recurrent CNA signatures implies the presence of causal mechanisms most likely implicated in the pathogenesis and disease-outcome of ccRCC tumours distinguishing lower from higher malignant tumours. The diagnostic quality of initial 201 genes (108 genes supporting G1 and 93 genes G3 phenotypes) has been successfully validated on published Swiss data (GSE19949) leading to a restricted CNA gene set of 171 CNA genes of which 85 genes favour Fuhrman grade G1 and 86 genes Fuhrman grade G3. Regarding these gene sets overall survival decreased with the number of G3 related gene losses plus G3 related gene gains. CNA gene sets presented define an entry to a gene-directed and pathway-related functional understanding of ongoing copy number alterations within and between individual ccRCC tumours leading to CNA genes of prognostic and predictive value.

Immune Gene Expression Is Associated with Genomic Aberrations in Breast Cancer

The presence of tumor-infiltrating lymphocytes (TIL) is a favorable prognostic factor in breast cancer, but what drives immune infiltration remains unknown. Here we examine if clonal heterogeneity, total mutation load, neoantigen load, copy number variations (CNV), gene- or pathway-level somatic mutations, or germline polymorphisms (SNP) are associated with immune metagene expression in breast cancer subtypes. Thirteen published immune metagenes correlated separately with genomic metrics in the three major breast cancer subtypes. We analyzed RNA-Seq, DNA copy number, mutation and germline SNP data of 627 ER⁺, 207 HER2⁺, and 191 triple-negative (TNBC) cancers from The Cancer Genome Atlas. P-values were adjusted for multiple comparisons, and permutation testing was used to assess false discovery rates. Increased immune metagene expression associated significantly with lower clonal heterogeneity estimated by MATH score in all subtypes and with a trend for lower overall mutation, neoantigen, and CNV loads in TNBC and HER2⁺ cancers. In ER⁺ cancers, mutation load, neoantigen load, and CNV load weakly but positively associated with immune infiltration, which reached significance for overall mutation load only. No highly recurrent single gene or pathway level mutations associated with immune infiltration. High immune gene expression and lower clonal heterogeneity in TNBC and HER2⁺ cancers suggest an immune pruning effect and equilibrium between immune surveillance and clonal expansion. Thus, immune checkpoint inhibitors may tip the balance in favor of immune surveillance in these cancers. Cancer Res; 77(12); 3317-24. ©2017 AACR.

Cancer Stem Cells and Their Microenvironment: Biology and Therapeutic Implications

Tumor consists of heterogeneous cancer cells including cancer stem cells (CSCs) that can terminally differentiate into tumor bulk. Normal stem cells in normal organs regulate self-renewal within a stem cell niche. Likewise, accumulating evidence has also suggested that CSCs are maintained extrinsically within the tumor microenvironment, which includes both cellular and physical factors. Here, we review the significance of stromal cells, immune cells, extracellular matrix, tumor stiffness, and hypoxia in regulation of CSC plasticity and therapeutic resistance. With a better understanding of how CSC interacts with its niche, we are able to identify potential therapeutic targets for the development of more effective treatments against cancer.

Rhodomycin A, a novel Src-targeted compound, can suppress lung cancer cell progression via modulating Src-related pathways

Src activation is involved in cancer progression and the interplay with EGFR. Inhibition of Src activity also represses the signalling pathways regulated by EGFR. Therefore, Src has been considered a target molecule for drug development. This study aimed to identify the compounds that target Src to suppress lung cancer tumourigenesis and metastasis and investigate their underlying molecular mechanisms. Using a molecular docking approach and the National Cancer Institute (NCI) compound dataset, eight candidate compounds were selected, and we evaluated their efficacy. Among them, rhodomycin A was the most efficient at reducing the activity and expression of Src in a dose-dependent manner, which was also the case for Src-associated proteins, including EGFR, STAT3, and FAK. Furthermore, rhodomycin A significantly suppressed cancer cell proliferation, migration, invasion, and clonogenicity in vitro and tumour growth in vivo. In addition, rhodomycin A rendered gefitinib-resistant lung adenocarcinoma cells more sensitive to gefitinib treatment, implying a synergistic effect of the combination therapy. Our data also reveal that the inhibitory effect of rhodomycin A on lung cancer progression may act through suppressing the Src-related multiple signalling pathways, including PI3K, JNK, Paxillin, and p130cas. These findings will assist the development of anti-tumour drugs to treat lung cancer.

Sustained proliferation in cancer: Mechanisms and novel therapeutic targets

Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression.

Bench to bedside: NK cells and control of metastasis

Natural killer (NK) cells play a critical role in host immune responses against tumor growth and metastasis. The numerous mechanisms used by NK cells to regulate and control cancer metastasis include interactions with tumor cells via specific receptors and ligands as well as direct cytotoxicity and cytokine-induced effector mechanisms. NK cells also play a role in tumor immunosurveillance and inhibition of metastases formation by recognition and killing of tumor cells. In this review, we provide an overview of the molecular mechanisms of NK cell responses against tumor metastases and discuss multiple strategies by which tumors evade NK cell-mediated surveillance. With an increasing understanding of the molecular mechanisms driving NK cell activity, there is a growing potential for the development of new cancer immunotherapies. Here we provide a historical background on NK cell-based therapies and discuss the implications of recent and ongoing clinical trials using novel NK cell-based immunotherapy.

Fascin is involved in the chemotherapeutic resistance of breast cancer cells predominantly via the PI3K/Akt pathway

Background:

A major therapeutic challenge for breast cancer is the ability of cancer cells to evade killing of conventional chemotherapeutic agents. We have recently reported the actin-bundling protein (fascin) as a major regulator of breast cancer metastasis and survival.

Methods:

Survival of breast cancer patients that received chemotherapy and xenograft tumour model was used to assess the effect of chemotherapy on fascin-positive and -negative breast cancer cells. Molecular and cellular assays were used to gain in-depth understanding of the relationship between fascin and chemoresistance.

Results:

We showed a significant correlation between fascin expression and shorter survival in breast cancer patients who received chemotherapy. In xenograft experiments, fascin-positive cancer cells displayed significantly more resistance to chemotherapy-mediated apoptotic cell death than fascin-negative counterparts. This increased chemoresistance was at least partially mediated through PI3K/Akt signalling, and was paralleled by increased FAK phosphorylation, enhanced expression of the inhibitor of apoptosis proteins (XIAP and Livin) and suppression of the proapoptotic markers (caspase 9, caspase 3 and PARP).

Conclusions:

This is the first report to demonstrate fascin involvement in breast cancer chemotherapeutic resistance, supporting the development of fascin-targeting drugs for better treatment of chemoresistance breast cancer.

Phosphorylation of PRAS40-Thr246 involved in renal lipid accumulation of diabetes

Lipid accumulation of kidney is a threat to renal physiological function of diabetes. The previous studies on diabetic nephropathy have demonstrated that activated Akt was involved in renal lipogenesis through enhancing transcription factor SREBP-1. PRAS40 is one of the downstream targets of activated Akt that was reported to involve in lipid metabolism in hepatic cells. However, it is still not clear whether PRAS40 is also involved in the renal lipogenesis of diabetes. Our study revealed that phosphorylation of PRAS40-Thr246 known as inactivated style increased in renal tubular cells of diabetic rats accompanied with over-expression of phospho-Akt, SREBP-1, and ADRP. In addition, in vitro experiment also found that high glucose enhanced expression of phospho-PRAS40-Thr246 followed by increased SREBP-1 and lipid droplets in HKC cells. After treated with LY294002, high glucose-induced HKC cells showed decreased phospho-PRAS40-Thr246, phospho-Akt-Ser473, and SREBP-1. Furthermore, wild type PRAS40 vector-caused increased phospho-PRAS40-Thr246 exaggerated lipid deposits in high glucose-treated HKC cells, which was effectively prevented in cells transfected with mutant PRAS40 vector (T246A). These above data suggested that phosphorylation of PRAS40-Thr246 mediated abnormal lipid metabolism in kidney of diabetes and might be the potential target for treating lipogenesis of diabetic nephropathy.

Induction of ATM/ATR pathway combined with Vγ2Vδ2 T cells enhances cytotoxicity of ovarian cancer cells

Many ovarian cancer cells express stress-related molecule MICA/B on their surface that is recognized by Vγ2Vδ2 T cells through their NKG2D receptor, which is transmitted to downstream stress-signaling pathway. However, it is yet to be established how Vγ2Vδ2 T cell-mediated recognition of MICA/B signal is transmitted to downstream stress-related molecules. Identifying targeted molecules would be critical to develop a better therapy for ovarian cancer cells. It is well established that ATM/ATR signal transduction pathways, which is modulated by DNA damage, replication stress, and oxidative stress play central role in stress signaling pathway regulating cell cycle checkpoint and apoptosis. We investigated whether ATM/ATR and its down stream molecules affect Vγ2Vδ2 T cell-mediated cytotoxicity. Herein, we show that ATM/ATR pathway is modulated in ovarian cancer cells in the presence of Vγ2Vδ2 T cells. Furthermore, downregulation of ATM pathway resulted downregulation of MICA, and reduced Vγ2Vδ2 T cell-mediated cytotoxicity. Alternately, stimulating ATM pathway enhanced expression of MICA, and sensitized ovarian cancer cells for cytotoxic lysis by Vγ2Vδ2 T cells. We further show that combining currently approved chemotherapeutic drugs, which induced ATM signal transduction, along with Vγ2Vδ2 T cells enhanced cytotoxicity of resistant ovarian cancer cells. These findings indicate that ATM/ATR pathway plays an important role in tumor recognition, and drugs promoting ATM signaling pathway might be considered as a combination therapy together with Vγ2Vδ2 T cells for effectively treating resistant ovarian cancer cells.

Identification of a role for the PI3K/AKT/mTOR signaling pathway in innate immune cells

The innate immune system is the first line of host defense against infection and involves several different cell types. Here we investigated the role of the phosphatidylinositol 3 kinase (PI3K) signaling pathway in innate immune cells. By blocking this pathway with pharmacological inhibitors, we found that the production of proinflammatory cytokines was drastically suppressed in monocytes and macrophages. Further study revealed that the suppression was mainly related to the mammalian target of rapamycin (mTOR)/p70^S6K signaling. In addition, we found that the PI3K pathway was involved in macrophage motility and neovascularization. Our data provide a rationale that inhibition of the PI3K signaling pathway could be an attractive approach for the management of inflammatory disorders.