Surface PD-L1, E-cadherin, CD24, and VEGFR2 as markers of epithelial cancer stem cells associated with rapid tumorigenesis

The angiogenic role of the alpha 9-nicotinic acetylcholine receptor in triple-negative breast cancers

Nicotine acts as an angiogenic factor by stimulating endogenous cholinergic pathways. Several subtypes of nicotinic acetylcholine receptors (nAChRs) have been demonstrated to be closely correlated to the formation and progression of different types of cancers. Recently, several studies have found that nicotinic acetylcholine receptors α9 (α9-nAChRs) are highly expressed in breast tumors, especially in tumors derived from patients diagnosed at advanced stages. In vitro studies have demonstrated that activation of α9-nAChRs is associated with increased proliferation and migration of breast cancer. To study the tumor-promoting role of α9-nAChRs in breast cancers, we generated a novel anti-α9-nAChR and methoxy-polyethylene glycol (mPEG) bispecific antibody (α9 BsAb) for dissecting the molecular mechanism on α9-nAChR-mediated tumor progression. Unexpectedly, we discovered the angiogenic role of α9-nAChR in nicotine-induced neovascularization of tumors. It revealed α9 BsAbs reduced nicotine-induced endothelial cell tube formation, blood vessel development in Matrigel plug assay and angiogenesis in microtube array membrane murine model (MTAMs). To unbraid the molecular mechanism of α9-nAChR in nicotine-mediated angiogenesis, the α9 BsAbs were applied and revealed the inhibitory roles in nicotine-induced production of hypoxia-inducible factor-2 alpha (HIF-2α), vascular endothelial growth factor A (VEGF-A), phosphorylated vascular endothelial growth factor receptor 2 (p-VEGFR2), vascular endothelial growth factor receptor 2 (VEGFR2) and matrix metalloproteinase-9 (MMP9) from triple-negative breast cancer cells (MDA-MB-231), suggesting α9-nAChRs played an important role in nicotine-induced angiogenesis. To confirm our results, the shRNA targeting α9-nAChRs was designed and used to silence α9-nAChR expression and then evaluated the angiogenic role of α9-nAChRs. The results showed α9 shRNA also played an inhibitory effect in blocking the nicotine-induced angiogenic signaling. Taken together, α9-nAChR played a critical role in nicotine-induced angiogenesis and this bispecific antibody (α9 BsAb) may serve as a potential therapeutic candidate for treatments of the α9 positive cancers.

Kaempferol inhibited invasion and metastasis of gastric cancer cells by targeting AKT/GSK3β pathway based on network pharmacology and molecular docking

This study aims to explore the mechanisms of the inhibitory effect of kaempferol on the invasion and metastasis of gastric cancer (GC) cells through network pharmacology prediction and experimental verification. It identifies core targets via PPI network analysis and finds that kaempferol binds to these targets well. In vitro experiments showed that kaempferol could inhibit the proliferation, colony formation, migration and invasion of GC cells. Western blotting indicated kaempferol may reduce AKT and GSK3β phosphorylation, leading to lower expression of invasion-related genes SRC, MMP9, CXCR4, KDR, and MMP2. Overall, kaempferol may prevent migration and invasion of GC cells via the AKT/GSK3β signaling pathway.

Pharmacological mechanism of quercetin in the treatment of colorectal cancer by network pharmacology and molecular simulation

Colorectal cancer is a serious threat to people's life due to its high incidence and high mortality. Quercetin can effectively treat colorectal carcinoma (CRC), but its exact mechanism of action is still unclear. Then quercetin-related target genes were obtained from Swiss Target Prediction database and Similarity Ensemble Approach (SEA) database, and CRC-related target genes were obtained from GeneCards database, respectively. Common target genes were obtained by FunRich software. String software was used to construct a protein-protein interaction (PPI) network. R package was used for gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Molecular docking, molecular dynamics (MD) simulation and post-dynamics simulation were used to explore the binding stability of quercetin to key targets. In total, 103 and 141 target information of quercetin were obtained from the Swiss Target Prediction database and SEA database, respectively. 1,649 CRC-related genes were obtained from GeneCards database. FunRich software was used to draw venny map and obtain 36 intersection targets of quercetin and CRC. String software was used to construct the PPI network. The core genes were AKT1, EGFR, MMP9, KDR, MET and PTK2. There were 532 items related to biological processes, 14 items related to cellular components, and 43 items related to molecular functions among the key target GO enrichment items. KEGG enrichment pathways of key targets involved cancer pathways, PI3K-Akt signal pathway, etc. The results of molecular docking, MD simulation and post-dynamics simulation showed they had a good affinity and formed a stable effect. So quercetin may play an important role in the treatment of CRC by acting on AKT1, EGFR, MMP9, KDR, MET and PTK2 to affect the development of CRC.Communicated by Ramaswamy H. Sarma.

Surprising magic of CD24 beyond cancer

CD24 has emerged as a molecule of significant interest beyond the oncological arena. Recent studies have unveiled its surprising and diverse roles in various biological processes and diseases. This review encapsulates the expanding spectrum of CD24 functions, delving into its involvement in immune regulation, cancer immune microenvironment, and its potential as a therapeutic target in autoimmune diseases and beyond. The 'magic' of CD24, once solely attributed to cancer, now inspires a new paradigm in understanding its multifunctionality in human health and disease, offering exciting prospects for medical advancements.

Improving cancer immunotherapy by preventing cancer stem cell and immune cell linking in the tumor microenvironment

Cancer stem cells are the key link between malignant tumor progression and drug resistance. This cell population has special properties that are different from those of conventional tumor cells, and the role of cancer stem cell-related exosomes in progression of tumor malignancy is becoming increasingly clear. Cancer stem cell-derived exosomes carry a variety of functional molecules involved in regulation of the microenvironment, especially with regard to immune cells, but how these exosomes exert their functions and the specific mechanisms need to be further clarified. Here, we summarize the role of cancer stem cell exosomes in regulating immune cells in detail, aiming to provide new insights for subsequent targeted drug development and clinical strategy formulation.

Inhibition of VEGFR2 and EGFR signaling cooperatively suppresses the proliferation of oral squamous cell carcinoma

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently overexpressed in oral squamous cell carcinoma (OSCC), and EGFR-targeting therapeutics have been widely employed to treat patients with a variety of carcinomas including OSCC. Here, we aimed to investigate alternative signaling for OSCC survival under the disruption of EGFR signaling.

METHODS

OSCC cell lines, namely HSC-3 and SAS, were utilized to investigate how EGFR disruption affects cell proliferation. Gene set enrichment analysis was performed to examine how EGFR disruption affects oncogenic signaling in OSCC cells. Disruption of KDR gene was performed using CRISPR/Cas9 techniques. A VEGFR inhibitor, vatalanib was used to research the impact of VEGFR inhibition on OSCC survival.

RESULTS

EGFR disruption significantly decreased the proliferation and oncogenic signaling including Myc and PI3K-Akt, in OSCC cells. Chemical library screening assays revealed that VEGFR inhibitors continued to inhibit the proliferation of EGFR-deficient OSCC cells. In addition, CRISPR-mediated disruption of KDR/VEGFR2 retarded OSCC cell proliferation. Furthermore, combined erlotinib-vatalanib treatment exhibited a more potent anti-proliferative effect on OSCC cells, compared to either monotherapy. The combined therapy effectively suppressed the phosphorylation levels of Akt but not p44/42.

CONCLUSION

VEGFR-mediated signaling would be an alternative signaling pathway for the survival of OSCC cells under the disruption of EGFR signaling. These results highlight the clinical application of VEGFR inhibitors in the development of multi-molecular-targeted therapeutics against OSCC.

CD24 blockade as a novel strategy for cancer treatment

The CD24 protein is a heat-stable protein with a small core that undergoes extensive glycosylation. It is expressed on the surface of various normal cells, including lymphocytes, epithelial cells, and inflammatory cells. CD24 exerts its function by binding to different ligands. Numerous studies have demonstrated the close association of CD24 with tumor occurrence and progression. CD24 not only facilitates tumor cell proliferation, metastasis, and immune evasion but also plays a role in tumor initiation, thus, serving as a marker on the surface of cancer stem cells (CSCs). Additionally, CD24 induces drug resistance in various tumor cells following chemotherapy. To counteract the tumor-promoting effects of CD24, several treatment strategies targeting CD24 have been explored, such as the use of CD24 monoclonal antibodies (mAb) alone, the combination of CD24 and chemotoxic drugs, or the combination of these drugs with other targeted immunotherapeutic techniques. Regardless of the approach, targeting CD24 has demonstrated significant anti-tumor effects. Therefore, the present study focuses on anti-tumor therapy and provides a comprehensive review of the structure and fundamental physiological function of CD24 and its impact on tumor development, and suggests that targeting CD24 may represent an effective strategy for treating malignant tumors.

Recent Advancement of PD-L1 Detection Technologies and Clinical Applications in the Era of Precision Cancer Therapy

Programmed death-1 is a protein found on the surface of immune cells that can interact with its ligand, programmed death-ligand 1 (PD-L1), which is expressed on the plasma membrane, the surface of secreted cellular exosomes, in cell nuclei, or as a circulating soluble protein. This interaction can lead to immune escape in cancer patients. In clinical settings, PD-L1 plays an important role in tumor disease diagnosis, determining therapeutic effectiveness, and predicting patient prognosis. PD-L1 inhibitors are also essential components of tumor immunotherapy. Thus, the detection of PD-L1 levels is crucial, especially in the era of precision cancer therapy. In recent years, innovations have been made in traditional immunoassay methods and the development of new immunoassays for PD-L1 detection. This review aims to summarize recent research progress in tumor PD-L1 detection technology and highlight the clinical applications of PD-L1.

Identifying tumor immunity-associated molecular features in liver hepatocellular carcinoma by multi-omics analysis

Background: Although current immunotherapies have achieved some successes for hepatocellular carcinoma (HCC) patients, their benefits are limited for most HCC patients. Therefore, the identification of biomarkers for promoting immunotherapeutic responses in HCC is urgently needed.

Methods: Using the TCGA HCC cohort, we investigated correlations of various molecular features with antitumor immune signatures (CD8⁺ T cell infiltration and cytolytic activity) and an immunosuppressive signature (PD-L1 expression) in HCC. These molecular features included mRNAs, microRNAs (miRNAs), long non-coding RNAs (lncRNAs), proteins, and pathways.

Results: We found that the mutations of several oncogenes and tumor suppressor genes significantly correlated with reduced antitumor immune signatures, including TTN, CTNNB1, RB1, ZFHX4, and TP53. It indicates that these genes’ mutations may inhibit antitumor immune responses in HCC. Four proteins (Syk, Lck, STAT5, and Caspase-7) had significant positive expression correlations with CD8⁺ T cell enrichment, cytolytic activity, and PD-L1 expression in HCC. It suggests that these proteins’ expression could be useful biomarkers for the response to immune checkpoint inhibitors Similiarly, we identified other types of biomarkers potentially useful for predicting the response to ICIs, including miRNAs (hsa-miR-511-5p, 150-3p, 342-3p, 181a-3p, 625-5p, 4772-3p, 155-3p, 142-5p, 142-3p, 155-5p, 625-3p, 1976, 7702), many lncRNAs, and pathways (apoptosis, cytokine-cytokine receptor interaction, Jak-STAT signaling, MAPK signaling, PI3K-AKT signaling, HIF-1 signaling, ECM receptor interaction, focal adhesion, and estrogen signaling). Further, tumor mutation burden showed no significant correlation with antitumor immunity, while tumor aneuploidy levels showed a significant negative correlation with antitumor immunity.

Conclusion: The molecular features significantly associated with HCC immunity could be predictive biomarkers for immunotherapeutic responses in HCC patients. They could also be potential intervention targets for boosting antitumor immunity and immunotherapeutic responses in HCC.

Classical epithelial-mesenchymal transition (EMT) and alternative cell death process-driven blebbishield metastatic-witch (BMW) pathways to cancer metastasis

Metastasis is a pivotal event that accelerates the prognosis of cancer patients towards mortality. Therapies that aim to induce cell death in metastatic cells require a more detailed understanding of the metastasis for better mitigation. Towards this goal, we discuss the details of two distinct but overlapping pathways of metastasis: a classical reversible epithelial-to-mesenchymal transition (hybrid-EMT)-driven transport pathway and an alternative cell death process-driven blebbishield metastatic-witch (BMW) transport pathway involving reversible cell death process. The knowledge about the EMT and BMW pathways is important for the therapy of metastatic cancers as these pathways confer drug resistance coupled to immune evasion/suppression. We initially discuss the EMT pathway and compare it with the BMW pathway in the contexts of coordinated oncogenic, metabolic, immunologic, and cell biological events that drive metastasis. In particular, we discuss how the cell death environment involving apoptosis, ferroptosis, necroptosis, and NETosis in BMW or EMT pathways recruits immune cells, fuses with it, migrates, permeabilizes vasculature, and settles at distant sites to establish metastasis. Finally, we discuss the therapeutic targets that are common to both EMT and BMW pathways.

Influence of KDR Genetic Variation on the Effectiveness and Safety of Bevacizumab in the First-Line Treatment for Patients with Advanced Colorectal Cancer

Objective

Bevacizumab is usually considered a first-line anti-tumor therapy, which inhibits tumor growth by downregulating the vascular endothelial growth factor (VEGF) that further silences the activity of the kinase insert region receptor (KDR) gene. In the current study, we investigated the treatment response of bevacizumab in advanced colorectal cancer (CRC) patients bearing 889 C>T mutation in the KDR gene.

Methods

A total of 135 advanced CRC patients were treated with bevacizumab along with chemotherapy at the seventh medical center of the People’s Liberation Army general hospital from January 2012 to June 2021 and were analyzed retrospectively. The KDR genotyping and mRNA expression analyses were performed in 57 patients.

Results

The KDR genotyping revealed 97 (71.85%) cases with CC genotype, 34 (25.19%) cases with CT, and 4 (2.96%) cases with TT genotype, while the minor allele frequency of 889 C>T was found as 0.16. The median progression-free survival (PFS) of the patients with CT/TT genotype and CC genotype was found to be 6.1 and 9.7 months, respectively (P = 0.009). The median overall survival (OS) of the two genotypes was 13.7 and 19.7 (P = 0.025), respectively. Multivariable Cox regression analysis of PFS, CT/TT genotype was found to be an independent factor for PFS (odds ratio (OR) = 1.88, P = 0.023). Additionally, the mRNA expression of KDR in 57 biopsies taken from patients with CT/TT genotypes was significantly higher than that of patients with CC genotype (P < 0.001). Additionally, in terms of safety, 55 patients experienced grade 2 or higher fatigue (incidence rate 40.74%) after receiving bevacizumab along with chemotherapy.

Conclusion

The 889 C>T mutation in KDR gene affects the KDR expression in colorectal cancer patients, thereby affecting the effectiveness of bevacizumab therapy.

Implication of Polymorphism on the Prognosis of Anlotinib Monotherapy for Patients With Treatment-Refractory Advanced NSCLC: An Exploratory Study

Background: This study aimed to investigate the implication of Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) polymorphism on the prognosis of anlotinib monotherapy among patients with treatment-refractory advanced nonsmall cell lung cancer (NSCLC). Methods: Designed as a retrospective study, this study included a total of 129 patients with treatment-refractory advanced NSCLC who were administered with anlotinib monotherapy. The efficacy of the patients was assessed regularly. The prognosis was performed and adverse reactions during anlotinib administration were collected. Available and appropriate biological specimens of the 129 patients were collected to perform VEGFR2 polymorphism analysis and VEGFR2 gene mRNA expression analysis accordingly. Association analysis between genotype status of VEGFR2 polymorphism and other variables was implemented in univariate and multivariate analysis. Results: Efficacy data indicated that the objective response rate (ORR) and disease control rate (DCR) of the 129 patients with NSCLC who received anlotinib monotherapy was 9.3% (95% CI: 4.9%-15.7%) and 78.3% (95%CI: 70.2%-85.1%), respectively. Additionally, prognostic data suggested that the median progression-free survival (PFS) and overall survival (OS) of the 129 patients with NSCLC were 4.1 months (95%CI: 2.84-5.36) and 10.1 months (95%CI: 8.58-11.62), respectively. Furthermore, polymorphism analysis indicated that polymorphism of 4397T>C in VEGFR2 was of clinical significance in the exploratory analysis, which exhibited that the median PFS of patients with TC/CC and TT genotype of 4397T>C polymorphism were 2.8 and 5.0 months, respectively (P = .009). Additionally, patients with TT genotype conferred a superior OS compared with those with TC/CC genotype (median OS: 11.5 vs 7.3 months, P = .016). Interestingly, mRNA expression of the VEGFR2 gene suggested that mRNA expression of VEGFR2 in PBMC specimens of patients with TC/CC genotype was significantly higher than that of patients with TT genotype (P < .001). Conclusion: Anlotinib monotherapy exhibited potential efficacy for patients with treatment-refractory advanced NSCLC. VEGFR2 polymorphism 4397T>C might be used as a promising biomarker to predict the survival of patients with NSCLC who received anlotinib administration.

Comprehensive Analysis of VEGFR2 Expression in HPV-Positive and -Negative OPSCC Reveals Differing VEGFR2 Expression Patterns

VEGF signaling regulated by the vascular endothelial growth factor receptor 2 (VEGFR2) plays a decisive role in tumor angiogenesis, initiation and progression in several tumors including HNSCC. However, the impact of HPV-status on the expression of VEGFR2 in OPSCC has not yet been investigated, although HPV oncoproteins E6 and E7 induce VEGF-expression. In a series of 56 OPSCC with known HPV-status, VEGFR2 expression patterns were analyzed both in blood vessels from tumor-free and tumor-containing regions and within tumor cells by immunohistochemistry using densitometry. Differences in subcellular colocalization of VEGFR2 with endothelial, tumor and stem cell markers were determined by double-immunofluorescence imaging. Immunohistochemical results were correlated with clinicopathological data. HPV-infection induces significant downregulation of VEGFR2 in cancer cells compared to HPV-negative tumor cells (p = 0.012). However, with respect to blood vessel supply, the intensity of VEGFR2 staining differed only in HPV-positive OPSCC and was upregulated in the blood vessels of tumor-containing regions (p < 0.0001). These results may suggest different routes of VEGFR2 signaling depending on the HPV-status of the OPSCC. While in HPV-positive OPSCC, VEGFR2 might be associated with increased angiogenesis, in HPV-negative tumors, an autocrine loop might regulate tumor cell survival and invasion.

Current understanding of cancer-intrinsic PD-L1: regulation of expression and its protumoral activity

In the last decade, we have witnessed an unprecedented clinical success in cancer immunotherapies targeting the programmed cell-death ligand 1 (PD-L1) and programmed cell-death 1 (PD-1) pathway. Besides the fact that PD-L1 plays a key role in immune regulation in tumor microenvironment, recently a plethora of reports has suggested a new perspective of non-immunological functions of PD-L1 in the regulation of cancer intrinsic activities including mesenchymal transition, glucose and lipid metabolism, stemness, and autophagy. Here we review the current understanding on the regulation of expression and intrinsic protumoral activity of cancer-intrinsic PD-L1.

CD24, A Review of its Role in Tumor Diagnosis, Progression and Therapy

CD24, is a mucin-like GPI-anchored molecules. By immunohistochemistry, it is widely detected in many solid tumors, such as breast cancers, genital system cancers, digestive system cancers, neural system cancers and so on. The functional roles of CD24 are either fulfilled by combination with ligands or participate in signal transduction, which mediate the initiation and progression of neoplasms. However, the character of CD24 remains to be intriguing because there are still opposite voices about the impact of CD24 on tumors. In preclinical studies, CD24 target therapies, including monoclonal antibodies, target silencing by RNA interference and immunotherapy, have shown us brighten futures on the anti-tumor application. Nevertheless, evidences based on clinical studies are urgently needed. Here, with expectancy to spark new ideas, we summarize the relevant studies about CD24 from a tumor perspective.

Mutant p53s and chromosome 19 microRNA cluster overexpression regulate cancer testis antigen expression and cellular transformation in hepatocellular carcinoma

A subset of hepatocellular carcinoma (HCC) overexpresses the chromosome 19 miRNA cluster (C19MC) and is associated with an undifferentiated phenotype marked by overexpression of cancer testis antigens (CTAs) including anti-apoptotic melanoma-A antigens (MAGEAs). However, the regulation of C19MC miRNA and MAGEA expression in HCCs are not understood. Here we show that, C19MC overexpression is tightly linked to a sub-set of HCCs with transcription-incompetent p53. Using next-generation and Sanger sequencing we found that, p53 in Hep3B cells is impaired by TP53-FXR2 fusion, and that overexpression of the C19MC miRNA-520G in Hep3B cells promotes the expression of MAGEA-3, 6 and 12 mRNAs. Furthermore, overexpression of p53-R175H and p53-R273H mutants promote miR-520G and MAGEA RNA expression and cellular transformation. Moreover, IFN-γ co-operates with miR-520G to promote MAGEA expression. On the other hand, metals such as nickel and zinc promote miR-526B but not miR-520G, to result in the suppression of MAGEA mRNA expression, and evoke cell death through mitochondrial membrane depolarization. Therefore our study demonstrates that a MAGEA-promoting network involving miR-520G, p53-defects and IFN-γ that govern cellular transformation and cell survival pathways, but MAGEA expression and survival are counteracted by nickel and zinc combination.

The Influence of KDR Genetic Variation on the Efficacy and Safety of Patients With Advanced NSCLC Receiving First-Line Bevacizumab Plus Chemotherapy Regimen

Objective:

Angiogenesis plays an important role in the growth and metastasis of non-small cell lung cancer (NSCLC). Bevacizumab is a humanized monoclonal antibody that mainly acts on vascular endothelial growth factor A (VEGFA). Kinase insert domain receptor (KDR) is the most important target of VEGFA. The aim of present study was to investigate the influence of KDR genetic variation on the efficacy and safety of patients with advanced NSCLC receiving first-line bevacizumab plus chemotherapy regimen.

Methods:

A total of 169 patients with advanced NSCLC who received bevacizumab combined with chemotherapy were recruited in this study. Clinical outcome of the regimens was evaluated in the hospital. Peripheral blood and biopsy tissue specimens of patients were collected for the genotyping of KDR genetic variation and KDR mRNA expression, respectively. The association between KDR genotype status and other variables were analyzed. Univariate analysis of genotype status and prognosis was implemented using the Kaplan-Meier survival analysis method. Multivariate Cox regression analysis was performed to adjust the confounding factors.

Results:

Of the polymorphisms analyzed, only V297 L was of clinical significance. The prevalence of V297 L among the study population were as follows: CC genotype 123 cases (72.8%), CT genotype 41 cases (24.3%), TT genotype 5 cases (2.9%). The minimum allele frequency is 0.15. The distribution frequencies of the 3 genotypes corresponded with Hardy-Weinberg equilibrium (P = 0.489). Patients with TT and CT genotypes were merged in the subsequent comparison of clinical outcomes. The analysis of efficacy exhibited that the objective response rates (ORR) of patients with CC genotype and CT/TT genotypes were 52.8% and 47.8% (P = 0.561), respectively. Prognosis indicated that the median progression free survival (PFS) of patients with CC genotype and CT/TT genotype were 8.9 and 5.5 months, respectively (P = 0.006). The median OS of the 2 genotypes were 20.0 and 14.9 months, respectively (P = 0.021). Adjusted in multivariate Cox regression analysis of PFS, CT/TT genotypes were an independent factor for PFS [hazard ratio (HR) = 1.59, P = 0.011). Safety profile according to genotype status of V297 L failed to find significant difference. Interestingly, the expression of KDR mRNA of patients with CT/TT genotype was significantly higher than that of patients with CC genotype in the 58 cancer tissue specimens (P < 0.001).

Conclusion:

The clinical comes of patients with advanced NSCLC receiving first-line bevacizumab plus chemotherapy regimens might be impacted by polymorphism V297 L through mediating the mRNA expression of KDR.

Immune evasion by cancer stem cells

Tumor immunity represents a new avenue for cancer therapy. Immune checkpoint inhibitors have successfully improved outcomes in several tumor types. In addition, currently, immune cell-based therapy is also attracting significant attention. However, the clinical efficacy of these treatments requires further improvement. The mechanisms through which cancer cells escape the immune response must be identified and clarified. Cancer stem cells (CSCs) play a central role in multiple aspects of malignant tumors. CSCs can initiate tumors in partially immunocompromised mice, whereas non-CSCs fail to form tumors, suggesting that tumor initiation is a definitive function of CSCs. However, the fact that non-CSCs also initiate tumors in more highly immunocompromised mice suggests that the immune evasion property may be a more fundamental feature of CSCs rather than a tumor-initiating property. In this review, we summarize studies that have elucidated how CSCs evade tumor immunity and create an immunosuppressive milieu with a focus on CSC-specific characteristics and functions. These profound mechanisms provide important clues for the development of novel tumor immunotherapies.

Programmed Death-Ligand 1 as a Regulator of Tumor Progression and Metastasis

Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) immune checkpoint has long been implicated in modeling antitumor immunity; PD-1/PD-L1 axis inhibitors exert their antitumor effects by relieving PD-L1-mediated suppression on tumor-infiltrating T lymphocytes. However, recent studies have unveiled a distinct, tumor-intrinsic, potential role for PD-L1. In this review, we focus on tumor-intrinsic PD-L1 signaling and delve into preclinical evidence linking PD-L1 protein expression with features of epithelial-to-mesenchymal transition program, cancer stemness and known oncogenic pathways. We further summarize data from studies supporting the prognostic significance of PD-L1 in different tumor types. We show that PD-L1 may indeed have oncogenic potential and act as a regulator of tumor progression and metastasis.

Sustained oxidative stress instigates differentiation of cancer stem cells into tumor endothelial cells: Pentose phosphate pathway, reactive oxygen species and autophagy crosstalk

Tumor angiogenesis plays a vital role in tumor growth and metastasis. It is proven that in tumor vasculature, endothelial cells (ECs) originate from a small population of cancer cells introduced as cancer stem cells (CSCs). Autophagy has a vital role in ECs differentiation from CSCs and tumor angiogenesis. High levels of reactive oxygen species (ROS) increased autophagy by inhibition of glucose-6-phosphate dehydrogenase (G6PD) and inactivation of the pentose phosphate pathway (PPP). Previously, we suggested that cancer cells initially increase the glycolysis rate when encountering ROS, then the metabolic balance is changed from glycolysis to PPP, following the continuation of oxidative stress. In this study, we investigate the possible role of persistent oxidative stress in the differentiation of CSCs into tumor ECs by relying on the relationship between the ROS, PPP and autophagy. Because tumor angiogenesis plays an important role in the growth and development of cancer, understanding the mechanisms involved in differentiating ECs from CSCs can help find promising treatments for cancer.

Targeting K-Ras and apoptosis-driven cellular transformation in cancer

Cellular transformation is a major event that helps cells to evade apoptosis, genomic instability checkpoints, and immune surveillance to initiate tumorigenesis and to promote progression by cancer stem cell expansion. However, the key molecular players that govern cellular transformation and ways to target cellular transformation for therapy are poorly understood to date. Here we draw key evidences from the literature on K-Ras-driven cellular transformation in the context of apoptosis to shed light on the key players that are required for cellular transformation and explain how aiming p53 could be useful to target cellular transformation. The defects in key apoptosis regulators such as p53, Bax, and Bak lead to apoptosis evasion, cellular transformation, and genomic instability to further lead to stemness, tumorigenesis, and metastasis via c-Myc-dependent transcription. Therefore enabling key apoptotic checkpoints in combination with K-Ras inhibitors will be a promising therapeutic target in cancer therapy.

Influence of KDR Genetic Variation on the Efficacy and Safety of Patients with Chemotherapy Refractory Metastatic CRC Who Received Apatinib Treatment

Background

The aim of the present study was to investigate the influence of kinase insert domain containing receptor (KDR) genetic variation on the efficacy of treatment and safety of patients with chemotherapy-refractory metastatic colorectal cancer (CRC) receiving apatinib.

Methods

A total of 108 patients with chemotherapy refractory metastatic CRC who were treated with apatinib participated in this study retrospectively. Efficacy of the patients' treatment was evaluated. Prognosis was carried out and safety profile was documented, respectively. Blood specimens and peripheral blood mononuclear cells (PBMC) of the patients were obtained for the analysis of genetic variation and KDR gene mRNA expression, respectively. The association between genotype status and clinical outcomes was presented.

Results

Objective response rate (ORR) and disease control rate (DCR) of the 108 patients with metastatic CRC receiving apatinib treatment were 5.6% and 69.4%, respectively. Survival analysis results exhibited that the median progression-free survival (PFS) and overall survival (OS) of the 108 patients with metastatic CRC was 3.6 months (95% confidence interval (CI): 3.03-4.17 months) and 8.9 months (95% CI: 7.57-10.23 months), respectively. Subsequently, the analysis of KDR genetic variation indicated that rs2071559 was of clinical significance. The minor allele frequency of rs2071559 was 0.22 and the genotype status corresponded with Hardy-Weinberg equilibrium (P=0.949). Prognosis analysis in a dominant inheritance manner through the combination of patients with TC and CC genotype showed that the median PFS of patients with TT genotype and TC/CC genotype was 4.1 and 3.0 months, respectively (P=0.012). Furthermore, the median OS of patients with the two genotypes was 10.5 and 6.1 months, respectively (P=0.007). Additionally, multivariate Cox regression analysis of OS showed that TC/CC genotype was an independent factor for OS (Hazard ratio (HR)=0.65, P=0.021). Interestingly, mRNA expression analysis suggested that the mRNA expression of KDR in PBMC differed significantly according to rs2071559 genotype status (P<0.001).

Conclusion

Apatinib demonstrated a potentially superior clinical outcome for patients with chemotherapy-refractory metastatic CRC. KDR polymorphism rs2071559 could be used as a potential biomarker for the prognosis evaluation of patients with CRC receiving apatinib therapy.

Targeting Host Cellular Factors as a Strategy of Therapeutic Intervention for Herpesvirus Infections

Herpesviruses utilize various host factors to establish latent infection, survival, and spread disease in the host. These factors include host cellular machinery, host proteins, gene expression, multiple transcription factors, cellular signal pathways, immune cell activation, transcription factors, cytokines, angiogenesis, invasion, and factors promoting metastasis. The knowledge and understanding of host genes, protein products, and biochemical pathways lead to discovering safe and effective antivirals to prevent viral reactivation and spread infection. Here, we focus on the contribution of pro-inflammatory, anti-inflammatory, and resolution lipid metabolites of the arachidonic acid (AA) pathway in the lifecycle of herpesvirus infections. We discuss how various herpesviruses utilize these lipid pathways to their advantage and how we target them to combat herpesvirus infection. We also summarize recent development in anti-herpesvirus therapeutics and new strategies proposed or under clinical trials. These anti-herpesvirus therapeutics include inhibitors blocking viral life cycle events, engineered anticancer agents, epigenome influencing factors, immunomodulators, and therapeutic compounds from natural extracts.

Expression of activated VEGFR2 by R1051Q mutation alters the energy metabolism of Sk-Mel-31 melanoma cells by increasing glutamine dependence

Vascular endothelial growth factor receptor 2 (VEGFR2) activating mutations are emerging as important oncogenic driver events. Understanding the biological implications of such mutations may help to pinpoint novel therapeutic targets. Here we show that activated VEGFR2 via the pro-oncogenic R1051Q mutation induces relevant metabolic changes in melanoma cells. The expression of VEGFR2^R1051Q leads to higher energy metabolism and ATP production compared to control cells expressing VEGFR2^WT. Furthermore, activated VEGFR2^R1051Q augments the dependence on glutamine (Gln) of melanoma cells, thus increasing Gln uptake and their sensitivity to Gln deprivation and to inhibitors of glutaminase, the enzyme initiating Gln metabolism by cells. Overall, these results highlight Gln addiction as a metabolic vulnerability of tumors harboring the activating VEGFR2^R1051Q mutation and suggest novel therapeutic approaches for those patients harboring activating mutations of VEGFR2.

Influence of VEGFR2 gene polymorphism on the clinical outcomes of apatinib for patients with chemotherapy-refractory extensive-stage SCLC: a real-world retrospective study

PURPOSE

Great individual differences were observed regarding the efficacy of apatinib clinically. The aim of present study was to investigate the influence of vascular endothelial growth factor receptor2 (VEGFR2) gene polymorphism on the clinical outcomes of apatinib for patients with chemotherapy-refractory extensive-stage small cell lung cancer (ES-SCLC).

METHODS

A total of 128 patients with chemotherapy-refractory ES-SCLC who were treated with apatinib at an initial dosage of 250 or 500 mg were included in this study. The change of target lesions was assessed. Overall response rate (ORR) was evaluated. Prognosis was carried out and safety profile was documented. Additionally, peripheral blood and biopsy cancer tissue specimens of the patients with SCLC were collected for the analysis of polymorphism and VEGFR2 gene mRNA expression, respectively. The association between genotype status and baseline characteristics was performed. Univariate analysis of genotype status and prognosis was carried out using Kaplan-Meier survival analysis and multivariate analysis were adjusted by Cox regression analysis.

RESULTS

Efficacy of apatinib included partial response (PR) in 15 patients, stable disease (SD) in 86 patients, progressive disease (PD) in 27 patients. Therefore, ORR of the 128 patients with ES-SCLC was 11.7%, and disease control rate (DCR) was 78.9%. Prognosis suggested that the median progression-free survival (PFS) and overall survival (OS) of the 128 patients with ES-SCLC was 4.2 months and 8.2 months, respectively. The polymorphism analysis focusing on VEGFR2 gene indicated that one single nucleotide polymorphism 889C>T was of clinical significance. Prevalence of 889C>T among the 128 patients with SCLC were as follows: CC genotype 87 cases (68.0%), CT genotype 38 cases (29.7%) and TT genotype 3 cases (2.3%), the minor allele frequency of 889C>T was 0.17, which was in accordance with Hardy-Weinberg Equilibrium (P = 0.628). Patients with CT and TT genotypes were merged in the subsequent analysis. Prognosis analysis exhibited that the median PFS of patients with CT/TT genotype and CC genotype was 3.3 and 5.0 months, respectively (P = 0.02). Furthermore, the median OS of patients was 5.5 and 9.0 months, respectively (P = 0.008). Additionally, multivariate Cox regression analysis of OS demonstrated that CT/TT genotype was an independent factor for OS [Hazard ratio (HR) = 0.64, P = 0.019]. However, the safety profile according to genotype status of 889C>T failed to show significant difference. Interestingly, mRNA expression analysis suggested that the mRNA expression of VEGFR2 in cancer tissues were significantly different according to CC and CT/TT genotypes (P < 0.001).

CONCLUSION

The administration with apatinib for patients with chemotherapy-refractory ES-SCLC was of potential clinical significance. The clinical outcomes of patients with ES-SCLC who were treated with apatinib could be impacted by VEGFR2 889C>T polymorphism through mediating the VEGFR2 mRNA expression.

Regulation of MYO18B mRNA by a network of C19MC miRNA-520G, IFN-γ, CEBPB, p53 and bFGF in hepatocellular carcinoma

MYO18B has been proposed to contribute to the progression of hepatocellular carcinoma (HCC). However, the signals that govern MYO18B transcription are not known. Here we show that, a network of C19MC miRNA-520G, IFN-γ, CEBPB and p53 transcriptional-defects promote MYO18B mRNA expression in HCCs. IFN-γ by itself suppresses MYO18B transcription, but promotes it when miRNA-520G is stably overexpressed. Similarly, CEBPB-liver-enriched activator protein (LAP) isoform overexpression suppresses MYO18B transcription but promotes transcription when the cells are treated with IFN-γ. Furthermore, miR-520G together with mutant-p53 promotes MYO18B transcription. Conversely, bFGF suppresses MYO18B mRNA irrespective of CEBPB, miR-520G overexpression or IFN-γ treatment. Finally high MYO18B expression reflects poor prognosis while high MYL5 or MYO1B expression reflects better survival of HCC patients. Thus, we identified a network of positive and negative regulators of MYO18B mRNA expression which reflects the survival of HCC patients.

PD-L1 Under Regulation of miR-429 Influences the Sensitivity of Gastric Cancer Cells to TRAIL by Binding of EGFR

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has received extensive attention as a cancer therapeutic due to its high propensity for tumor targeting with minimal toxicity to healthy tissue. Gastric cancer (GCa) cells show high levels of TRAIL resistance. Epidermal growth factor receptor (EGFR) antagonizes TRAIL-induced apoptosis, but the mechanisms of these effects remain unclear. Our past research confirmed TRAIL-resistant (BGC823 and SGC7901) and TRAIL-sensitive cells (HGC27 and MKN45). miR-429 associated with TRAIL sensitivity was screened using microRNA arrays. The transfection of mimics and inhibitors confirmed that miR-429 negatively correlated with GCa TRAIL resistance. The target gene of miR-429 was identified as PD-L1, which positively correlated with TRAIL resistance through gene silencing and recovery experiments. Using co-immunoprecipitation (co-IP) and proximity ligation assay, we demonstrated that the pro-survival effects of PD-L1 are mediated through the binding and activation of EGFR. Cell viability experiments demonstrated that PD-L1 is key to the maintenance of cell viability in TRAIL-treated cells. This indicated that PD-L1 binds to and participates in EGFR activation through miR-429 regulation to antagonize TRAIL-induced apoptosis. This provides a new theoretical basis for the combination of the EGFR monoclonal antibodies including cetuximab, PD-L1 inhibitors, and human recombinant TRAIL in gastric cancer therapy and can filter patients who are currently sensitive to TRAIL treatment.

Clinical outcomes and safety of apatinib monotherapy in the treatment of patients with advanced epithelial ovarian carcinoma who progressed after standard regimens and the analysis of the VEGFR2 polymorphism

The aims of the present study were to investigate the clinical outcomes and safety of apatinib monotherapy in the treatment of patients with advanced epithelial ovarian carcinoma (EOC) who have progressed after standard regimens, and to analyze the vascular endothelial growth factor receptor 2 (VEGFR2) rs2071559 polymorphism. A total of 118 patients with advanced EOC who received apatinib treatment were included in the study. Tumor response was evaluated using progression-free survival (PFS) and overall survival (OS) time, and safety data were documented. Additionally, peripheral blood and peripheral blood mononuclear cell (PBMC) specimens from the patients with EOC were collected to perform the genotyping of genetic polymorphism and assess the mRNA expression of VEGFR2, respectively. The objective response rate across the 118 patients with advanced EOC was 38.98%, the disease control rate was 63.56%, the median PFS time was 4.65 months and the median OS time was 15.10 months. Regarding the polymorphism analysis, the prevalence of rs2071559 in VEGFR2 among the 118 patients with advanced EOC was recorded as the TT genotype in 72 cases (61.02%), TC genotype in 41 cases (34.75%) and CC genotype in 5 cases (4.23%), and the minor allele frequency of rs2071559 was 0.22. The distribution of the three genotypes was in accordance with the Hardy-Weinberg equilibrium (P=0.781). TC and CC genotypes were merged in the subsequent analysis. The prognosis analyses suggested that the median PFS time of patients with the TC/CC genotype and the TT genotype was 3.10 and 5.40 months, respectively (P=0.015). Moreover, the median OS time of the two genotypes was 12.60 and 17.50 months, respectively (P=0.009). However, no association was noted between genotype status of the polymorphism and adverse reactions. Additionally, the mRNA expression analysis indicated that the mRNA expression levels of VEGFR2 in PBMC specimens were significantly different between TT and TC/CC genotypes (P<0.001). The present study suggested that the clinical outcomes of patients with advanced EOC, who progressed after standard regimens and received apatinib treatment, might be influenced by the VEGFR2 rs2071559 polymorphism.

PD-L1 promotes tumor growth and progression by activating WIP and β-catenin signaling pathways and predicts poor prognosis in lung cancer

PD-L1 is overexpressed in tumor cells and contributes to cancer immunoevasion. However, the role of the tumor cell-intrinsic PD-L1 in cancers remains unknown. Here we show that PD-L1 regulates lung cancer growth and progression by targeting the WIP and β-catenin signaling. Overexpression of PD-L1 promotes tumor cell growth, migration and invasion in lung cancer cells, whereas PD-L1 knockdown has the opposite effects. We have also identified WIP as a new downstream target of PD-L1 in lung cancer. PD-L1 positively modulates the expression of WIP. Knockdown of WIP also inhibits cell viability and colony formation, whereas PD-L1 overexpression can reverse this inhibition effects. In addition, PD-L1 can upregulate β-catenin by inhibiting its degradation through PI3K/Akt signaling pathway. Moreover, we show that in lung cancer cells β-catenin can bind to the WIP promoter and activate its transcription, which can be promoted by PD-L1 overexpression. The in vivo experiments in a human lung cancer mouse model have also confirmed the PD-L1-mediated promotion of tumor growth and progression through activating the WIP and β-catenin pathways. Furthermore, we demonstrate that PD-L1 expression is positively correlated with WIP in tumor tissues of human adenocarcinoma patients and the high expression of PD-L1 and WIP predicts poor prognosis. Collectively, our results provide new insights into understanding the pro-tumorigenic role of PD-L1 and its regulatory mechanism on WIP in lung cancer, and suggest that the PD-L1/Akt/β-catenin/WIP signaling axis may be a potential therapeutic target for lung cancers.

Overcoming Wnt-β-catenin dependent anticancer therapy resistance in leukaemia stem cells

Leukaemia stem cells (LSCs) underlie cancer therapy resistance but targeting these cells remains difficult. The Wnt-β-catenin and PI3K-Akt pathways cooperate to promote tumorigenesis and resistance to therapy. In a mouse model in which both pathways are activated in stem and progenitor cells, LSCs expanded under chemotherapy-induced stress. Since Akt can activate β-catenin, inhibiting this interaction might target therapy-resistant LSCs. High-throughput screening identified doxorubicin (DXR) as an inhibitor of the Akt-β-catenin interaction at low doses. Here we repurposed DXR as a targeted inhibitor rather than a broadly cytotoxic chemotherapy. Targeted DXR reduced Akt-activated β-catenin levels in chemoresistant LSCs and reduced LSC tumorigenic activity. Mechanistically, β-catenin binds multiple immune-checkpoint gene loci, and targeted DXR treatment inhibited expression of multiple immune checkpoints specifically in LSCs, including PD-L1, TIM3 and CD24. Overall, LSCs exhibit distinct properties of immune resistance that are reduced by inhibiting Akt-activated β-catenin. These findings suggest a strategy for overcoming cancer therapy resistance and immune escape.

The efficacy and safety of Apatinib mesylate in the treatment of metastatic osteosarcoma patients who progressed after standard therapy and the VEGFR2 gene polymorphism analysis

OBJECTIVE

The aim of this study was to investigate the efficacy and safety of Apatinib mesylate in the treatment of metastatic osteosarcoma patients who progressed after standard therapy and the VEGFR2 gene polymorphism analysis.

METHODS

Designed as a retrospective study, a total of 105 metastatic osteosarcoma patients who progressed after standard therapy were included in this study. The metastatic osteosarcoma patients received 500-750 mg Apatinib mesylate according to body surface area until disease progression or unacceptable toxicity with 28 days one cycle. Overall response was evaluated after two cycles Apatinib treatment, then progression-free survival (PFS) and overall survival (OS) were evaluated, and safety data were recorded. Additionally. peripheral blood and peripheral blood mononuclear cell (PBMC) specimens in the osteosarcoma patients were collected for the genotyping of VEGFR2 genetic variation and mRNA expression, respectively. Analysis on the association between genotype and baseline characteristics and VEGFR2 gene mRNA expression was analyzed. The univariate analysis of genotypes and prognosis was carried out by Kaplan-Meier survival analysis, and multivariate analysis was adjusted by Cox regression analysis.

RESULTS

The objective response rate (ORR) of the 105 metastatic osteosarcoma patients was 37.14%, disease control rate (DCR) was 77.14%, median PFS was 4.1 months, and median OS was 9.0 months. Regarding the VEGFR2 gene polymorphisms analysis, only - 906 T > C was of clinical significance. The prevalence of - 906 T > C in VEGFR2 among the study population was as follows: TT genotype 62 cases (59.05%), TC genotype 36 cases (34.29%) and CC genotype 7 cases (6.66%), minor allele frequency of - 906 T > C was 0.24. Compared with patients with TC/CC genotype, patients with TT genotype showed longer median PFS (5.0 versus 3.1 months, P = 0.011) and median OS (9.8 versus 7.6 months, P = 0.032). There was no correlation between the polymorphism and adverse reactions. Additionally, the mRNA expression in 69 randomly selected sample indicated that the mRNA expression of VEGFR2 of the patients with CC/TC genotypes were significantly higher than those of the TT genotype patients (P < 0.001).

CONCLUSION

Apatinib was safe and effective in the treatment of metastatic osteosarcoma patients who progressed after standard therapy. The clinical outcomes of Apatinib may be influenced by the polymorphism - 906 T > C of VEGFR2 through mediating the mRNA expression of VEGFR2.

Clinical Outcomes and Safety of Apatinib Mesylate in the Treatment of Advanced Non-Squamous Non-Small Cell Lung Cancer in Patients Who Progressed After Standard Therapy and Analysis of the KDR Gene Polymorphism

Purpose

This study investigated the clinical outcomes and safety of apatinib mesylate in the treatment of advanced non-squamous non-small cell lung cancer (NSCLC) in patients who progressed after standard therapy, and analyzed the kinase insert domain receptor (KDR) gene polymorphism.

Methods

A total of 135 patients with advanced non-squamous NSCLC who received apatinib mesylate were included. Objective response rates were evaluated. Subsequently, progression-free survival (PFS) and overall survival (OS) were assessed and safety data were recorded. Additionally, peripheral blood and biopsy cancer tissue specimens were collected from the patients with NSCLC for the genotyping of the genetic polymorphism and mRNA expression of the KDR gene, respectively. Analysis on the association between genotypes and prognosis was conducted.

Results

The objective response rate of the 135 patients with NSCLC was 18.52%, disease control rate was 65.19%, median PFS was 3.95 months, and median OS was 10.05 months. Regarding the KDR gene polymorphism analysis, the distribution of the 4397T>C polymorphism genotypes was in accordance with the Hardy–Weinberg Equilibrium (P=0.868). Moreover, the prognosis analysis indicated that the median PFS of patients with the CC/TC and TT genotypes was 2.80 and 4.80 months, respectively (P=0.002). Furthermore, the median OS of patients with the two genotypes was 9.10 and 10.56 months, respectively (P=0.041). The multivariate Cox regression analysis showed that the TC/CC genotypes were an independent factor for PFS (odds ratio: 1.72, P=0.009). There was no correlation between the polymorphism and adverse reactions. Additionally, the mRNA expression analysis suggested that the mRNA levels of KDR in cancer tissues were significantly different between the TT and TC/CC genotypes (P<0.001).

Conclusion

The clinical outcomes of treatment with apatinib mesylate for advanced non-squamous NSCLC in patients who progressed after standard therapy may be influenced by the KDR 4397T>C polymorphism through mediation of the mRNA expression of KDR.

Dormant tumor cells interact with memory CD8+ T cells in RET transgenic mouse melanoma model

Melanoma is an aggressive form of skin-cancer. Melanoma cells are characterized by their plasticity, resulting in therapy resistance. Using RET transgenic mouse melanoma model, we characterized dormant tumor cells accumulated in the bone marrow (BM) and investigated their interaction with effector memory CD8⁺ T cells. We found that cells expressing melanoma-associated antigen tyrosinase related protein (TRP)-2 and stemness marker CD133 represented less than 1.5% of all melanoma cells in primary skin lesions and metastatic lymph nodes. The majority of these cells were negative for the proliferation marker Ki67. In the BM, CD133⁺TRP-2⁺ melanoma cells displayed an aberrant expression of p16, p27, Ki67 and PCNA proteins, suggesting their dormant phenotype. Moreover, these cells were characterized by an elevated expression of various molecules characterized stemness, metastatic, angiogenic and immunosuppressive properties such as CD271, CD34, HIF-1α, CXCR3, CXCR4, VEGR2, PD-L1, CTLA-4, CD39 and CCR4 as compared to their CD133^- counterparts. Disseminated BM dormant TRP-2⁺ tumor cells were found to be co-localized with memory CD8⁺ T cells. Our data suggest that these dormant melanoma cells in the BM could play an important role in the maintenance of memory T cells in the BM.

Cell stemness, epithelial-to-mesenchymal transition, and immunoevasion: Intertwined aspects in cancer metastasis

Recent advances in tumor immunology, fostered by dramatic outcomes with cancer immunotherapy, have opened new scenarios in cancer metastasis. The cancer stemness/mesenchymal phenotype and an excess of immune suppressive signals are emerging as Intertwined aspects of human tumors. This review examines recent studies that explored the mechanistic links between cancer cell stemness and immunoevasion, and the evidence points to these key events in cancer metastasis as two sides of the same coin. This review also covers the mechanisms involved in tumor expression of programmed cell death ligand 1 (PD-L1), a major factor exploited by human neoplasias to suppress immune control. We highlight the convergence of mesenchymal traits and PD-L1 expression and examine the functions of this immune inhibitory molecule, which confers cancer cell resistance and aggressiveness.

Recent Advances in Cancer Stem Cell-Targeted Immunotherapy

Cancer stem cells (CSCs) are one of the reasons for the relapse of cancer cells and metastasis. They have drug resistance against most chemotherapeutic agents. CSCs are also responsible for tumor cell heterogeneity and cause minimal residual disease. In order to achieve complete regression of tumors, CSCs have to be targeted. Recent advances in immunotherapies have shown promising outcomes in curing cancer, which are also applicable to target CSCs. CSCs express immune markers and exhibit specific immune characteristics in various cancers, which can be used in immunotherapies to target CSCs in the tumor microenvironment. Recently, various strategies have been used to target CSCs. Adaptive T-cells, dendritic cell (DC)-based vaccines, oncolytic viruses, immune checkpoint inhibitors, and combination therapies are now being used to target CSCs. Here, we discuss the feasibility of these immunological approaches and the recent trends in immunotherapies to target CSCs.

VEGFR2 promotes tumorigenesis and metastasis in a pro-angiogenic-independent way in gastric cancer

Background

VEGF/VEGFR2 pathway is the central therapeutic target in anti-angiogenic treatment in multiple cancers. However, little work has been carried out concerning the pro-malignancy functions of VEGFR2 that are independent of its pro-angiogenesis effects in gastric cancer. Here, we demonstrated that VEGFR2 up-regulation in gastric cancer tissues was a prognostic marker for poor disease-free survival and overall survival of gastric cancer patients.

Methods

Immunohistochemistry was used to detect VEGFR2 and VTN expressions in specimens. Kaplan–Meier curves were constructed for survival analysis. Stably knockdown cell lines and overexpression cell lines were constructed by small interfering RNA and plasmids transfection. Real-time PCR and Western blot were used to confirm the expressions of target genes at both RNA and protein levels. Cell proliferation was measured by using Cell Counting Kit-8 and xenograft models. Microarray and bioinformatic analysis were also performed to identify the relationship between Vitronectin (VTN) and VEGFR2.

Results

When overexpressed in gastric cancer cells, VEGFR2 increased cellular proliferation and invasion in vitro and tumor formation in xenograft models. By using integrating microarray and bioinformatic analysis, we identifiedVTN as a downstream of VEGFR2 pathway. In gain- and loss-of function analysis in gastric cancer cells, VTN was further verified in consistent with VEGFR2 in expression levels and in regulating cell growth and motility in vitro and in vivo. Moreover, in gastric cancer samples, VTN was as also revealed as a poor prognostic factor.

Conclusions

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects.

Implications

Our present findings defined a novel activity for VEGFR2 in promoting tumorogenicity, motility and indicating a poor survival in gastric cancer beyond its known pro-angiogenic effects, which may provide a new and valuable target for design of therapies for intervention and a new cognitive perspective for the anti-angiogenesis therapies.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5322-0) contains supplementary material, which is available to authorized users.

Insluin and epithelial growth factor (EGF) promote programmed death ligand 1(PD-L1) production and transport in colon cancer stem cells

Background

Programmed cell death ligand 1 (PD-L1) is an important immune-inhibitory protein expressed on cancer cells to mediate cancer escape through interaction with PD-1 expressed on activated T lymphocytes (T cells). Previously, we reported that colon and breast cancer stem cells (CSCs) expressed much higher levels of PD-L1 than their parental cells, suggesting they will be more resistant to immune attack.

Methods

We investigated the underlining mechanism of PD-L1 increase in colon CSCs, with a special focus on the effect of insulin and epithelial growth factor (EGF), the two fundamental components to sustain the metabolism and stemness in the culture of CSCs.

Results

We found that insulin increased the total and surface PD-L1 levels through PI3K/Akt/mTOR pathway as the increase could be inhibited by the dual inhibitor of the pathway, BEZ235. EGF didn’t affect the total PD-L1 levels of CSCs but increased the cell surface protein levels by flow cytometry analysis, indicating EGF promotes the transport of PD-L1 to the cell surface. Blocking cell surface PD-L1 with a specific antibody resulted in a significant reduction of tumour sphere formation but didn’t interfere with the sphere growth, suggesting that cell surface PD-L1 may act as an adhering molecule for CSCs.

Conclusions

Apart from the essential roles in metabolism and stemness, insulin and EGF involve in up-regulation of PD-L1 expression in colon CSCs, therefore the inhibition of insulin and EGF/EGFR pathways can be considered for cancer immunotherapy or combined with PD-1/PD-L1 antibody-based cancer immunotherapy to eliminate CSCs.

An effective dendritic cell-based vaccine containing glioma stem-like cell lysate and CpG adjuvant for an orthotopic mouse model of glioma

Owing to the limited therapeutic efficacy of glioma vaccines, new strategies are required to improve cancer vaccines. Our study aimed to assess the therapeutic efficacy of a glioma vaccine called STDENVANT. This vaccine, comprising glioma stem-like cell (GSC) lysate, dendritic cells (DCs), and Toll-like receptor (TLR) 9 agonist CpG motif-containing oligodeoxynucleotides (CpG ODNs), was assessed using a GL261-C57BL/6 orthotopic mouse model of glioma. STDENVANT markedly improved survival and tumor regression by enhancing anti-tumor immune function. Moreover, STDENVANT upregulated programmed death 1 (PD-1) and its ligand PD-L1 on effector T cells, DCs, and glioma tissues, resulting in the accumulation of regulatory T (Treg) cells in the brain and lymph nodes. Combinatorial administration of anti-PD-L1 antibody and STDENVANT conferred a greater survival advantage and decreased the Treg cell population in the brain. The present results indicate that PD-L1 blockade can promote tumor regression via STDENVANT in a mouse model of glioma, and combinatorial administration of anti-PD-L1 antibody and STDENVANT increases the therapeutic anti-tumor efficacy of treatment.

Chromosome 19 miRNA cluster and CEBPB expression specifically mark and potentially drive triple negative breast cancers

Triple negative breast cancers (TNBCs) are known to express low PGR, ESR1, and ERBB2, and high KRT5, KRT14, and KRT17. However, the reasons behind the increased expressions of KRT5, KRT14, KRT17 and decreased expressions of PGR, ESR1, and ERBB2 in TNBCs are not fully understood. Here we show that, expression of chromosome 19 miRNA cluster (C19MC) specifically marks human TNBCs. Low REST and high CEBPB correlate with expression of C19MC, KRT5, KRT14, and KRT17 and enhancers of these genes/cluster are regulated by CEBPB and REST binding sites. The C19MC miRNAs in turn can potentially target REST to offer a positive feedback loop, and might target PGR, ESR1, ERBB2, GATA3, SCUBE2, TFF3 mRNAs to contribute towards TNBC phenotype. Thus our study demonstrates that C19MC miRNA expression marks TNBCs and that C19MC miRNAs and CEBPB might together determine the TNBC marker expression pattern.

Tumor-Intrinsic PD-L1 Signaling in Cancer Initiation, Development and Treatment: Beyond Immune Evasion

Although the role of PD-L1 in suppressing the anti-tumor immune response is extensively documented, recent discoveries indicate a distinct tumor-intrinsic role for PD-L1 in modulating epithelial-to-mesenchymal transition (EMT), cancer stem cell (CSC)-like phenotype, metastasis and resistance to therapy. In this review, we will focus on the newly discovered functions of PD-L1 in the regulation of cancer development, describe underlying molecular mechanisms responsible for PD-L1 upregulation and discuss current insights into novel components of PD-L1 signaling. Furthermore, we summarize our current understanding of the link between PD-L1 signaling and the EMT program as well as the CSC state. Tumor cell-intrinsic PD-L1 clearly contributes to cancer stemness, EMT, tumor invasion and chemoresistance in multiple tumor types. Conversely, activation of OCT4 signaling and upregulation of EMT inducer ZEB1 induce PD-L1 expression in cancer cells, thereby suggesting a possible immune evasion mechanism employed by cancer stem cells during metastasis. Our meta-analysis demonstrated that PD-L1 is co-amplified along with MYC, SOX2, N-cadherin and SNAI1 in the TCGA endometrial and ovarian cancer datasets. Further identification of immune-independent PD-L1 functions and characterization of crucial signaling events upstream or downstream of PD-L1 in diverse cancer types and specific cancer subtypes, would provide additional targets and new therapeutic approaches.

Stem cell properties of peripheral blood endothelial progenitors are stimulated by soluble CD146 via miR-21: potential use in autologous cell therapy

Cell-based therapies constitute a real hope for the treatment of ischaemic diseases. One of the sources of endothelial progenitors for autologous cell therapy is Endothelial Colony Forming Cells (ECFC) that can be isolated from peripheral blood. However, their use is limited by their low number in the bloodstream and the loss of their stem cell phenotype associated with the acquisition of a senescent phenotype in culture. We hypothesized that adding soluble CD146, a novel endothelial growth factor with angiogenic properties, during the isolation and growth procedures could improve their number and therapeutic potential. Soluble CD146 increased the number of isolated peripheral blood ECFC colonies and lowered their onset time. It prevented cellular senescence, induced a partial mesenchymal phenotype and maintained a stem cell phenotype by stimulating the expression of embryonic transcription factors. These different effects were mediated through the induction of mature miR-21. When injected in an animal model of hindlimb ischaemia, sCD146-primed ECFC isolated from 40 ml of blood from patients with peripheral arterial disease were able to generate new blood vessels and restore blood flow. Treatment with sCD146 could thus constitute a promising strategy to improve the use of autologous cells for the treatment of ischaemic diseases.

PD-L1 Expression On tumor Cells Was Associated With Unfavorable Prognosis In Esophageal Squamous Cell Carcinoma

Background: Evidence about the association between programmed cell death ligand 1 (PD-L1) expression and prognosis of esophageal squamous cell carcinoma (ESCC) were limited and controversial. Thus, the present study aims to investigate the prognostic value of tumor immune microenvironment (TIM) based on PD-L1 expression and CD8+ T cell infiltration in ESCC tissues.

Methods: From September 2008 to March 2010, a total of 146 ESCC patients received radical esophagectomy were retrospectively analyzed in our present study. PD-L1 expression and CD8+ T cell infiltration were evaluated through immunohistochemistry. The clinicopathological characteristics and survival were analyzed.

Results: There were 111 male and 35 female. The median age was 59.1 years (37-78 years). The positive rate of PD-L1 expression was 61.7%. The rate of high CD8+ T cell infiltration was 33%. No significant differences were found between clinicopathological features and PD-L1 expression or CD8+ T cell infiltration. PD-L1 expression was significantly associated with poor overall survival (P=0.010). However, CD8+ T cell infiltration was not a prognostic risk factor. Type of TIM was significantly associated with the prognosis of ESCC patients (P=0.021).

Conclusions: PD-L1 expression was an independent risk factor for the prognosis of ESCC patients. Immunotherapy may achieve promising outcomes in ESCC patients with type I TIM.

Enhanced Glioblastoma Targeting Ability of Carfilzomib Enabled by a DA7R-Modified Lipid Nanodisk

The robust proliferation of tumors relies on a rich neovasculature for nutrient supplies. Therefore, a basic strategy of tumor targeting therapy should include not only killing regular cancer cells but also blocking tumor neovasculature. D-peptide ^DA7R, which was previously reported to specifically bind vascular endothelial growth factor receptor 2 (VEGFR2) and neuropilin-1 (NRP-1), could achieve the goal of multitarget recognition. Accordingly, the main purposes of this work were to establish a carfilzomib-loaded lipid nanodisk modified with multifunctional peptide ^DA7R (^DA7R-ND/CFZ) and to evaluate its anti-glioblastoma efficacy in vitro and in vivo. It is testified that the ^DA7R peptide-conjugated lipid nanodisk can be specifically taken up by U87MG cells and HUVECs. Furthermore, ^DA7R-ND demonstrated a more enhanced penetration than that of the nonmodified formulation on the tumor spheroid model in vitro and more tumor region accumulation in vivo on the subcutaneous and intracranial tumor-bearing nude mice model. ^DA7R-ND was shown to co-localize with tumor neovasculature in vivo. When loaded with proteasome inhibitor carfilzomib, the ^DA7R-decorated nanodisk could remarkably suppress tumor proliferation, extend survival time of nude mice bearing an intracranial tumor, and inhibit neovasculature formation with an efficacy higher than that of the nonmodified nanodisk in vitro and in vivo. The present study verified that the heptapeptide ^DA7R-conjugated nanodisk is a promising nanocarrier for glioblastoma targeting therapy.

Molecular Pathogenesis of Radiation-Induced Cell Toxicity in Stem Cells

Radiation therapy is an effective cancer therapy, but damage to normal tissues surrounding the tumor due to radiotherapy causes severe complications. The importance of the therapeutic area between tumor suppression and normal tissue injury has long been highlighted in radiation therapy. Recent advances in stem cell biology have shown that stem cell (SC) responses to genotoxic stresses of ionizing radiation can improve the therapeutic effect of radiation by repairing damaged cells. In contrast, cancer stem cells (CSCs), a small subpopulation of cells within tumors, are generally resistant to chemotherapy and radiotherapy and cause tumor recurrence. Although the underlying mechanisms are not clearly understood in detail, efforts are still underway to identify SC treatment or CSC resistant pathogenesis of DNA damage agents such as radiation therapy. In response to radiation, CSCs differ from normal SCs in their biological properties due to severe deregulation of the self-renewal ability in CSCs. Differences of cleavage mode, cell cycle characteristics, replication potential, and activation/inactivation of DNA damage treatment and cancer-specific molecular pathways between normal SCs and CSCs confer a malignant phenotype upon CSCs. However, further studies are needed to identify normal SC and CSC-specific targets. In this review, we summarize the current advances in research regarding how normal SCs and CSCs respond to ionizing radiation, with a special emphasis on cell toxicity, radiosensitivity, signaling networks, DNA damage response (DDR) and DNA repair. In addition, we discuss strategies to develop new diagnostic and therapeutic techniques for predicting responses to cancer treatment and overcoming radiation-related toxicity.

Molecular genetics and cellular events of K-Ras-driven tumorigenesis

Cellular transformation and the accumulation of genomic instability are the two key events required for tumorigenesis. K-Ras (Kirsten-rat sarcoma viral oncogene homolog) is a prominent oncogene that has been proven to drive tumorigenesis. K-Ras also modulates numerous genetic regulatory mechanisms and forms a large tumorigenesis network. In this review, we track the genetic aspects of K-Ras signaling networks and assemble the sequence of cellular events that constitute the tumorigenesis process, such as regulation of K-Ras expression (which is influenced by miRNA, small nucleolar RNA and lncRNA), activation of K-Ras (mutations), generation of reactive oxygen species (ROS), induction of DNA damage and apoptosis, induction of DNA damage repair pathways and ROS detoxification systems, cellular transformation after apoptosis by the blebbishield emergency program and the accumulation of genomic/chromosomal instability that leads to tumorigenesis.