Targeting the tumor microenvironment as a potential therapeutic approach in colorectal cancer: Rational and progress

Effect of colorectal cancer stem cells on the development and metastasis of colorectal cancer

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role - immune checkpoints - and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

Cho W, Yang YJ, Azarian M, Shafiee Ardestani M, Nasiri N, Ramezani Farani M, Huh YS. Nanomedicine Strategies Utilizing Lipid-Based Nanoparticles for Liver Cancer Therapy: Exploring Signaling Pathways and Therapeutic Modalities

Liver cancer, specifically hepatocellular carcinoma (HCC), is the second leading cause of cancer-related deaths, following pancreatic cancer. The 5-year overall survival rate for HCC remains relatively low. Currently, there are multiple treatment options available for HCC, including systemic drugs, minimally invasive local therapies such as radiofrequency ablation, transarterial chemoembolization (TACE), and arterial radioembolization (TARE), as well as surgical interventions like liver resection or transplantation. However, the effectiveness of drug delivery to the cancerous liver is hindered by pathophysiological changes in the organ. In order to address this challenge, lipid-based nanoparticles (LNPs) have emerged as promising platforms for delivering a diverse range of therapeutic drugs. LNPs offer various structural configurations that enhance their physical stability and enable them to accommodate different types of cargo with varying mechanical properties and degrees of hydrophobicity. In this article, we provide a comprehensive review of the current applications of LNPs in the development of anti-HCC therapies. By examining the existing research, we aim to shed light on the potential future directions and advancements in this field.

Targeting integrin α5 in fibroblasts potentiates colorectal cancer response to PD-L1 blockade by affecting extracellular-matrix deposition

BACKGROUND

One reason patients with cancer cannot benefit from immunotherapy is the lack of immune cell infiltration in tumor tissues. Cancer-associated fibroblasts (CAFs) are emerging as central players in immune regulation that shapes tumor microenvironment (TME). Earlier we reported that integrin α5 was enriched in CAFs in colorectal cancer (CRC), however, its role in TME and cancer immunotherapy remains unclear. Here, we aimed to investigate the role for integrin α5 in fibroblasts in modulating antitumor immunity and therapeutic efficacy combined with checkpoint blockade in CRC.

METHODS

We analyzed the CRC single-cell RNA sequencing (scRNA-seq) database to define the expression of ITGA5 in CRC tumor stroma. Experimentally, we carried out in vivo mouse tumor xenograft models to confirm the targeting efficacy of combined α5β1 inhibition and anti-Programmed death ligand 1 (PD-L1) blockade and in vitro cell-co-culture assay to investigate the role of α5 in fibroblasts in affecting T-cell activity. Clinically, we analyzed the association between α5 expression and infiltrating T cells and evaluated their correlation with patient survival and immunotherapy prognosis in CRC.

RESULTS

We revealed that ITGA5 was enriched in FAP-CAFs. Both ITGA5 knockout fibroblasts and therapeutic targeting of α5 improved response to anti-PD-L1 treatment in mouse subcutaneous tumor models. Mechanistically, these treatments led to increased tumor-infiltrating CD8+ T cells. Furthermore, we found that α5 in fibroblasts correlated with extracellular matrix (ECM)-related genes and affected ECM deposition in CRC tumor stroma. Both in vivo analysis and in vitro culture and cell killing experiment showed that ECM proteins and α5 expression in fibroblasts influence T-cell infiltration and activity. Clinically, we confirmed that high α5 expression was associated with fewer CD3+ T and CD8+ T cells, and tissues with low α5 and high CD3+ T levels correlated with better patient survival and immunotherapy response in a CRC cohort with 29 patients.

CONCLUSIONS

Our study identified a role for integrin α5 in fibroblasts in modulating antitumor immunity by affecting ECM deposition and showed therapeutic efficacy for combined α5β1 inhibition and PD-L1 blockade in CRC.

Colorectal Cancer: Disease Process, Current Treatment Options, and Future Perspectives

Colorectal cancer (CRC) is one of the deadliest malignancies in the US, ranking fourth after lung, prostate, and breast cancers, respectively, in general populations. It continues to be a menace, and the incidence has been projected to more than double by 2035, especially in underdeveloped countries. This review seeks to provide some insights into the disease progression, currently available treatment options and their challenges, and future perspectives. Searches were conducted in the PubMed search engine in the university's online library. The keywords were "Colorectal Cancer" AND "disease process" OR "disease mechanisms" OR "Current Treatment" OR "Prospects". Selection criteria were original articles published primarily during the period of 2013 through 2023. Abstracts, books and documents, and reviews/systematic reviews were filtered out. Of over 490 thousand articles returned, only about 800 met preliminary selection criteria, 200 were reviewed in detail, but 191 met final selection criteria. Fifty-one other articles were used due to cross-referencing. Although recently considered a disease of lifestyle, CRC incidence appears to be rising in countries with low, low-medium, and medium social demographic indices. CRC can affect all parts of the colon and rectum but is more fatal with poor disease outcomes when it is right-sided. The disease progression usually takes between 7-10 years and can be asymptomatic, making early detection and diagnosis difficult. The CRC tumor microenvironment is made up of different types of cells interacting with each other to promote the growth and proliferation of the tumor cells. Significant advancement has been made in the treatment of colorectal cancer. Notable approaches include surgery, chemotherapy, radiation therapy, and cryotherapy. Chemotherapy, including 5-fluorouracil, irinotecan, oxaliplatin, and leucovorin, plays a significant role in the management of CRC that has been diagnosed at advanced stages. Two classes of monoclonal antibody therapies have been approved by the FDA for the treatment of colorectal cancer: the vascular endothelial growth factor (VEGF) inhibitor, e.g., bevacizumab (Avastin®), and the epidermal growth factor receptor (EGFR) inhibitor, e.g., cetuximab (Erbitux®) and panitumumab (Verbitix®). However, many significant problems are still being experienced with these treatments, mainly off-target effects, toxic side effects, and the associated therapeutic failures of small molecular drugs and the rapid loss of efficacy of mAb therapies. Other novel delivery strategies continue to be investigated, including ligand-based targeting of CRC cells.

Exosome-mediated crosstalk between tumor cells and innate immune cells: implications for cancer progression and therapeutic strategies

The increasing number of cancer-associated deaths despite the substantial improvement in diagnosis and treatment has sparked discussions on the need for novel biomarkers and therapeutic strategies for cancer. Exosomes have become crucial players in tumor development and progression, largely due to the diverse nature of their cargo content released to recipient cells. Importantly, exosome-mediated crosstalk between tumor and stromal cells is essential in reprogramming the tumor microenvironment to facilitate tumor progression. As a result, exosomes have gradually become a marker for the early diagnosis of many diseases and an important tool in drug delivery systems. However, the precise mechanisms by which exosomes participate in tumor progression remain elusive, multifaceted, and a double-edged sword, thus requiring further clarification. The available evidence suggests that exosomes can facilitate communication between innate immune cells and tumor cells to either support or inhibit tumor progression. Herein, this review focused on exosome-mediated intercellular communication between tumor cells and macrophages, neutrophils, mast cells, monocytes, dendritic cells, and natural killer cells. Specifically, how such intercellular communication affects tumor progression has been described. It has also been discussed that, depending on their cargo, exosomes can suppress or promote tumor cell progression. In addition, the potential application of exosomes and strategies to target exosomes in cancer treatment has been comprehensively discussed.

ZLDI-8 suppresses angiogenesis and vasculogenic mimicry in drug-resistant NSCLC in vitro and in vivo

AIMS

The chemotherapy drugs for NSCLC often face the consequences of treatment failure due to acquired drug resistance. Tumor chemotherapy resistance is often accompanied by angiogenesis. Here, we aimed to investigate the effect and underlying mechanisms of ADAM-17 inhibitor ZLDI-8 we found before on angiogenesis and vasculogenic mimicry(VM) in drug-resistant NSCLC.

MAIN METHODS

The tube formation assay was used to evaluate angiogenesis and VM. Migration and invasion were assessed with transwell assays in the co-culture condition. To explore the underlying mechanisms of how ZLDI-8 inhibited tubes formation, ELISA assay and western blot assay were preformed. The effects of ZLDI-8 on angiogenesis in vivo were investigated in Matrigel plug, CAM and Rat aortic ring assays.

KEY FINDINGS

In the present study, ZLDI-8 significantly inhibited the tube formation of human umbilical vein endothelial cells (HUVECs) in either normal medium or in tumor supernatants. Furthermore, ZLDI-8 also inhibited VM tubes formation of A549/Taxol cells. In the co-culture assay, the interaction between lung cancer cells and HUVECs promotes increased cell migration and invasion, while ZLDI-8 eliminates this promotion. Moreover, the VEGF secretion were decreased by ZLDI-8 and the expression of Notch1, Dll4, HIF1α and VEGF were inhibited by ZLDI-8. In addition, ZLDI-8 can inhibit blood vessel formation in the Matrigel plug, CAM and Rat aortic ring assays.

SIGNIFICANCE

ZLDI-8 inhibits angiogenesis and VM in drug-resistant NSCLC through suppressing Notch1-HIF1α-VEGF signaling pathway. This study lays the foundation for the discovery of drugs that inhibit angiogenesis and VM in drug resistant NSCLC.

CircRNAs: Roles in regulating head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC), the most common head and neck malignant tumor, with only monotherapy, is characterized by poor prognosis, and low 5-year survival rate. Due to the lack of therapeutic targets, the targeted drugs for HNSCC are rare. Therefore, exploring the regulation mechanism of HNSCC and identifying effective therapeutic targets will be beneficial to its treatment of. Circular RNA (CircRNA) is a class of RNA molecules with a circular structure, which is widely expressed in human body. CircRNAs regulate gene expression by exerting the function as a miRNA sponge, thereby mediating the occurrence and development of HNSCC cell proliferation, apoptosis, migration, invasion, and other processes. In addition, circRNAs are also involved in the regulation of tumor sensitivity to chemical drugs and other biological functions. In this review, we systematically listed the functions of circRNAs and explored the regulatory mechanisms of circRNAs in HNSCC from the aspects of tumor growth, cell death, angiogenesis, tumor invasion and metastasis, tumor stem cell regulation, tumor drug resistance, immune escape, and tumor microenvironment. It will assist us in discovering new diagnostic markers and therapeutic targets, while encourage new ideas for the diagnosis and treatment of HNSCC.

The role of the tumor microenvironment in colorectal cancer and the potential therapeutic approaches

BACKGROUND

Colorectal cancer (CRC) with a high prevalence is recognized as the fourth most common cause of cancer-related death globally. Over the past decade, there has been growing interest in the network of tumor cells, stromal cells, immune cells, blood vessel cells, and fibroblasts that comprise the tumor microenvironment (TME) to identify new therapeutic interventions.

METHODS

Databases, such as Google Scholar, PubMed, and Scopus, were searched to provide an overview of the recent research progress related to targeting the TME as a novel therapeutic approach.

RESULTS

Tumor microenvironment as a result of the cross talk between these cells may result in either advantages or disadvantages in tumor development and metastasis, affecting the signals and responses from the surrounding cells. Whilst chemotherapy has led to an improvement in CRC patients' survival, the metastatic aspect of the disease remains difficult to avoid.

CONCLUSIONS

The present review emphasizes the structure and function of the TME, alterations in the TME, its role in the incidence and progression of CRC, the effects on tumor development and metastasis, and also the potential of its alterations as therapeutic targets. It should be noted that providing novel studies in this field of research might help us to achieve practical therapeutic strategies based on their interaction.

AFF4 Predicts the Prognosis of Colorectal Cancer Patients and Suppresses Colorectal Cancer Metastasis via Promoting CDH1 Expression

INTRODUCTION

AF4/FMR2 family member 4 (AFF4) is a core component of super elongation complex (SEC) and regulates the transcription elongation of many genes. AFF4 depletion or amplification is associated with multiple cancers, but its role in colorectal cancer (CRC) has not been investigated so far.

METHODS

qRT-PCR and Western blot analyzed AFF4 expression in the paired clinical CRC tissues. The patients' overall survival curve was determined using the Kaplan-Meier plotter. In vitro experiments, such as cell proliferation, migration, and invasion, were used to preliminarily ascertain the role of AFF4 in CRC. A CRC cell liver metastasis animal model was well established. Livers were harvested and examined histologically by a series of indicators, such as tumor nodules, liver weight, ALT/AST activity, and tumor cell identification by hematoxylin-eosin (HE) staining.

RESULTS

We firstly examined the expression of AFF4 in colorectal cancer and normal tissues by collecting paired CRC tissues and adjacent normal tissues, revealing that AFF4 was significantly downregulated in CRC patients and lower expression of AFF4 was correlated with poor prognosis. Next, we observed that presence or absence of AFF4 in CRC cells had no effect on cancer cell proliferation, while AFF4 depletion significantly promoted the migration or invasion of CRC cells in vitro. Furthermore, we confirmed that AFF4 deficiency enhanced the metastatic capacity of CRC cells in vivo. Mechanistically, we found that AFF4 upregulated the transcription of CDH1 gene, which encodes E-cadherin and suppresses the epithelial-mesenchymal transition (EMT). Knockdown of AFF4 interfered with CDH1 transcription, resulting in downregulation of E-cadherin expression and the progression of CRC. Moreover, restored CDH1 expression could rescue the phenotype of CRC cells without AFF4.

CONCLUSIONS

Collectively, our data demonstrated that AFF4 served as a significant novel regulator of CRC via CDH1 transcriptional regulation and a potential effective therapy target for patients with CRC.

Effect, Mechanism, and Applications of Coding/Non-coding RNA m6A Modification in Tumor Microenvironment

The tumor microenvironment (TME), which includes immune cells, fibroblasts, and other components, is the site of tumor cell growth and metastasis and significantly impacts tumor development. Among them, N6-methyladenosine RNA modifications (m6A RNA modifications) are the most abundant internal modifications in coding and non-coding RNAs, which can significantly influence the cancer process and have potential as biomarkers and potential therapeutic targets for tumor therapy. This manuscript reviews the role of m6A RNA modifications in TME and their application in tumor therapy. To some extent, an in-depth understanding of the relationship between TME and m6A RNA modifications will provide new approaches and ideas for future cancer therapy.

Atovaquone-HSA nano-drugs enhance the efficacy of PD-1 blockade immunotherapy by alleviating hypoxic tumor microenvironment

Background

Hypoxia is inherent character of most solid malignancies, leading to the failure of chemotherapy, radiotherapy and immunotherapy. Atovaquone, an anti-malaria drug, can alleviate tumor hypoxia by inhibiting mitochondrial complex III activity. The present study exploits atovaquone/albumin nanoparticles to improve bioavailability and tumor targeting of atovaquone, enhancing the efficacy of anti-PD-1 therapy by normalizing tumor hypoxia.

Methods

We prepared atovaquone-loaded human serum albumin (HSA) nanoparticles stabilized by intramolecular disulfide bonds, termed HSA-ATO NPs. The average size and zeta potential of HSA-ATO NPs were measured by particle size analyzer. The morphology of HSA-ATO NPs was characterized by transmission electron microscope (TEM). The bioavailability and safety of HSA-ATO NPs were assessed by animal experiments. Flow cytometry and ELISA assays were used to evaluate tumor immune microenvironment.

Results

Our data first verified that atovaquone effectively alleviated tumor hypoxia by inhibiting mitochondrial activity both in vitro and in vivo, and successfully encapsulated atovaquone in vesicle with albumin, forming HSA-ATO NPs of approximately 164 nm in diameter. We then demonstrated that the HSA-ATO NPs possessed excellent bioavailability, tumor targeting and a highly favorable biosafety profile. When combined with anti-PD-1 antibody, we observed that HSA-ATO NPs strongly enhanced the response of mice bearing tumor xenografts to immunotherapy. Mechanistically, HSA-ATO NPs promoted intratumoral CD8⁺ T cell recruitment by alleviating tumor hypoxia microenvironment, thereby enhancing the efficacy of anti-PD-1 immunotherapy.

Conclusions

Our data provide strong evidences showing that HSA-ATO NPs can serve as safe and effective nano-drugs to enhance cancer immunotherapy by alleviating hypoxic tumor microenvironment.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-01034-9.

Exosomes: Emerging modulators of signal transduction in colorectal cancer from molecular understanding to clinical application

Exosomes are small cell derived membrane nano-vesicles that carry various components including lipids, proteins and nucleic acids. There is accumulating evidence that exosomes have a role in tumorigenesis, tumor invasiveness and metastasis. Furthermore, oncogene mutation may influence exosome release from tumor cells. Exosomes may induce colorectal cancer by altering signaling cascades such as the Wnt/β-catenin and KRAS pathways that are involved in cell proliferation, apoptosis, dissemination, angiogenesis, and drug resistance. The aim of this review was to overview recent findings evaluating the association between tumor cells-derived exosomes and their content in modulating signaling pathways in colorectal cancer.

Delivery of oxaliplatin to colorectal cancer cells by folate-targeted UiO-66-NH2

Oxaliplatin is being used in different malignancies and several side effects are reported for patients taking Oxaliplatin, including peripheral neuropathy, nausea and vomiting, diarrhea, mouth sores, low blood counts, fatigue, loss of appetite, etc. Here we have developed a targeted anticancer drug delivery system based on folate-conjugated amine-functionalized UiO-66 for the delivery of oxaliplatin (OX). UiO-66-NH₂ (U) and UiO-66-NH₂-FA(FU) were pre-functionalized by the incorporation of folic acid (FA) into the structure via coordination of the carboxylate group of FA. The FTIR spectra of drug-loaded U and FU showed the presence of new carboxylic and aliphatic groups of OX and FA. Powder X-ray diffraction (PXRD) patterns were matched accordingly with the reference pattern and FESEM results showed semi-spherical particles (115-128 nm). The evaluated amounts of OX in U and FU were calculated 304.5 and 293 mg/g_, respectively. The initial burst release of OX was 15.7% per hour for U(OX) and 10.8% per hour for FU(OX). The final release plateau gives 62.9% and 52.3% for U(OX) and FU(OX). To evaluate the application of the prepared delivery platform, they were tested on colorectal cancer cells (CT-26) via MTT assay, cell migration assay, and spheroid model. IC₅₀ values obtained from MTT assay were 21.38, 95.50, and 18.20 μg/mL for OX, U(OX), and FU(OX), respectively. After three days of treatment, the CT26 spheroids at two doses of 500 and 50 μg/mL of U(OX) and FU(OX) showed volume reduction. Moreover, the oxidative behavior of the prepared systems within the cell was assessed by total thiol, malondialdehyde, and superoxide dismutase activity. The results showed that FU(OX) had higher efficacy in preventing the growth of CT-26 spheroid, and was more effective than oxaliplation in cell migration inhibition, and induced higher oxidative stress and apoptosis.

Exosomal miR-30a and miR-222 derived from colon cancer mesenchymal stem cells promote the tumorigenicity of colon cancer through targeting MIA3

Background

Multipotent mesenchymal stem cells (MSCs) derived from virus tumors have been reported to contribute to malignant cell growth, invasion, and metastasis. However, the mechanism of communication between MSCs and colon cancer cells is poorly understood. Recent studies have suggested that exosomes are an important player in crosstalk between cells and could significantly suppress the invasion ability of human cancer cells (hCCs) when transfected with a microRNA inhibitor. However, to date, no study has illuminated the miRNA changes in exosomes derived from hCC-MSCs.

Methods

Colon cancer stem cells were cultured in medium and passaged to develop fibroblast-like morphology. Exosomes were collected using ExoQuick precipitation and exosome morphology was visualized by transmission electron microscopy. Small RNA sequencing was analyzed using an Illumina HiSeq4000 analyzer, and the expression of MIA3 was assessed by real-time PCR and Western blot. The functional roles of miR-30a and miR-222 in colon cancer cells were evaluated through cell and animal experiments.

Results

Our results showed that the characteristics of MSC-like cells (hCC-MSCs) derived from human colon cancer stem cells were comparable to those of bone marrow-derived MSCs, including surface antigens and the ability to multi-differentiate to osteocytes and adipocytes. Furthermore, we screened the microRNA (miRNA) profiles of exosomes derived from hCC-MSCs and the corresponding parent hCC-MSCs. We found a significant enrichment in the miR-30a and miR-222 level in hCC-MSC-derived exosomes. Furthermore, in vitro and in vivo experiments demonstrated that miR-30a and miR-222 bound to their shared downstream target, MIA3, to promote the ability of colon cells to proliferate, migrate, and metastasize, thus evidencing their functional roles as oncogenic miRNAs.

Conclusions

These data suggest that hCC-MSC-secreted exosomes promote colon cancer cell proliferation and metastasis through delivering miR-30a and miR-222. Subsequently, exosomal miR-30a and miR-222 simultaneously target MIA3, suppress its expression, and promote colon cell proliferation, migration, and metastasis.

Effect of Curcumin and Its Derivates on Gastric Cancer: Molecular Mechanisms

Gastric carcinoma is one of the most prevalent malignancies and is associated with a high mortality. Chemotherapy is the principal therapeutic option in the treatment of gastric cancer, but its success rate is restricted by severe side effects and the prevalence of chemo-resistance. Curcumin is a polyphenolic compound derived from turmeric that has potent antioxidant, anti-inflammatory and anti-tumor effects. There is accumulating evidence that curcumin may prevent gastric cancer through regulation of oncogenic pathways. Furthermore some curcumin analogues and novel formulation of curcumin appear to have anti-tumor activity. The aim of this review was to give an overview of the therapeutic potential of curcumin and its derivatives against gastric cancer in preclinical and clinical studies.

2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ) inhibits cancer cell metastasis behavior of TNBC via suppressing EMT and VEGF

Triple-negative breast cancer (TNBC) is highly metastatic and lacks effective therapeutic targets among several subtypes of breast cancer. Cancer metastasis promotes the malignancy of TNBC and is closely related to the poor prognosis of the TNBC patients. We aim to explore novel agents that effectively inhibit cancer metastasis to treat TNBC. In our study, 2-Methoxy-5((3,4,5-trimethosyphenyl)seleninyl) phenol (SQ), a CA-4 analogue, could inhibit cell motility and invasion in MDA-MB-231 cells, and the mechanism is closely associated to the inhibition of epithelial-to-mesenchymal transition (EMT). Meanwhile, SQ significantly inhibited the expression and secretion of vascular endothelial growth factor (VEGF) in MDA-MB-231 cells. Moreover, the conditioned medium from SQ-treated MDA-MB-231 cells significantly inhibited the motility and invasion of human umbilical vein endothelial cells (HUVECs), which was correlated with the inhibition of EMT process in HUVECs. In addition, exogenous application of VEGF reversed the occurrence of EMT in HUVECs which stimulated by conditioned medium from SQ-treated cells. Furthermore, SQ inhibited vasculogenic mimicry (VM) formation in MDA-MB-231 cells, which was associated with VE-cadherin and EphA2 down-regulation. This study indicates that SQ inhibits MDA-MB-231 cell metastasis through suppressing EMT and VEGF, thereby implicating this compound might be a potential therapeutic agent against metastatic TNBC.

Nuclear-localized costimulatory molecule 4-1BBL promotes colon cancer cell proliferation and migration by regulating nuclear Gsk3β, and is linked to the poor outcomes associated with colon cancer

Anti-tumor immune response and the prognosis of tumor are the results of competition between stimulatory and inhibitory checkpoints. Except for upregulating inhibitory checkpoints, lowering some immune accelerating molecules to convert an immunostimulatory microenvironment into an immunodormant one through "decelerating the accelerator" might be another effective immune escape pattern. 4-1BBL is a classical transmembrane costimulatory molecule involving in antitumor immune responses. In contrast, we demonstrated that 4-1BBL is predominantly localized in the nuclei of cancer cells in colon cancer specimens and is positively correlated with tumor size, lymph node metastasis, and a lower survival ratio. Furthermore, the nuclear localization of 4-1BBL was also ascertained in vitro. 4-1BBL knockout (KO) arrests the proliferation and impaired the migration and invasion ability of colon cancer cells in vitro and retarded tumor growth in vivo. 4-1BBL KO increased the accumulation of Gsk3β in the nuclei of colon cancer cells and consequently decreased the expression of Wnt pathway target genes and thus alter tumor biological behavior. We hypothesized that unlike membrane-expressed 4-1BBL, which stimulates the 4-1BB signaling of antitumor cytotoxic T cells, the nuclear-localized 4-1BBL could facilitate the malignant behavior of colon cancer cells by circumventing antitumor signaling and driving some key oncotropic signal pathway in the nucleus. Nuclear-localized 4-1BBL might be an indicator of colon cancer malignancy and serve as a promising target of immunotherapy.

Integrin α5 subunit is required for the tumor supportive role of fibroblasts in colorectal adenocarcinoma and serves as a potential stroma prognostic marker

The tumorigenesis of colorectal cancer (CRC) is a complicated process, involving interactions between cancer cells and the microenvironment. The role of α5 integrin subunit in CRC remains controversial, and previous studies mainly focused on cancer cells. Herein, we report an important role of α5 in stroma fibroblasts in the tumorigenesis of CRC. The expression of α5 was found to be located in colorectal tumor stroma rather than in epithelia cancer cells. Immunofluorescence colocalization and gene correlation analysis confirmed that α5 was mainly expressed in cancer-associated fibroblasts (CAFs). Moreover, experimental evidence showed that α5 expression was required for the tumor-promoting effect of fibroblast cells. In an in vivo xenograft nude mice model, α5 depletion in fibroblasts dramatically suppressed fibroblast-induced tumor growth. In an in vitro cell coculture assay, α5 depletion or knockdown reduced the ability of fibroblasts to promote cancer cell migration and invasion compared with wild-type fibroblasts; moreover, we observed that the expression and assembly of fibronectin were downregulated after α5 depletion or knockdown in fibroblasts. Analysis of the RNA-Seq data of the Cancer Genome Atlas cohort revealed that high expression of ITGA5 (α5 integrin subunit) was correlated with poor overall survival in colorectal adenocarcinoma, which was further confirmed by immunohistochemistry in an independent cohort of 355 patients. Thus, our study identifies α5 integrin subunit as a novel stroma molecular marker for colorectal adenocarcinoma, offers a fresh insight into colorectal adenocarcinoma progression, and shows that α5 expression in stroma fibroblasts underlies its ability to promote the tumorigenesis of colorectal adenocarcinoma.

CircCDR1as upregulates autophagy under hypoxia to promote tumor cell survival via AKT/ERK½/mTOR signaling pathways in oral squamous cell carcinomas

Autophagy, as an important non-selective degradation mechanism, could promote tumor initiation and progression by maintaining cellular homeostasis and the cell metabolism as well as cell viability. CircCDR1as has been shown to function as an oncogene in cancer progression, however, it remains largely unknown as to how autophagy is regulated by circCDR1as in oral squamous cell carcinoma (OSCC). In this study, we validated the functional roles of circCDR1as in regulation of autophagy in OSCC cells and further investigated how circCDR1as contributed to cell survival via up-regulating autophagy under a hypoxic microenvironment by using combination of human tissue model, in vitro cell experiments and in vivo mice model. We found that hypoxia promoted the expression level of circCDR1as in OSCC cells and elevated autophagy. In addition, circCDR1as further increased hypoxia-mediated autophagy by targeting multiple key regulators of autophagy. We revealed that circCDR1as enhanced autophagy in OSCC cells via inhibition of rapamycin (mTOR) activity and upregulation of AKT and ERK_½ pathways. Overexpression of circCDR1as enhanced OSCC cells viability, endoplasmic reticulum (ER) stress, and inhibited cell apoptosis under a hypoxic microenvironment. Moreover, circCDR1as promoted autophagy in OSCC cells by sponging miR-671-5p. Collectively, these results revealed that high expression of circCDR1as enhanced the viability of OSCC cells under a hypoxic microenvironment by promoting autophagy, suggesting a novel treatment strategy involving circCDR1as and the inhibition of autophagy in OSCC cells.

A nomogram to predict vascular invasion before resection of colorectal cancer

Vascular invasion (VI) is an important feature for systemic recurrence and an indicator for the application of adjuvant therapy in colorectal cancer (CRC). Preoperative knowledge of VI is important in determining whether adjuvant therapy is necessary, as well as the adequacy of surgical resection. In the present study, a predictive nomogram for VI in patients with CRC was constructed. The prediction model consisted of 664 eligible patients with CRC, who were divided into a training set (n=468) and a validation set (n=196). Data were collected between August 2013 and April 2018. The feature selection model was established using the least absolute shrinkage and selection operator regression model. Multivariable logistic regression analysis was used to construct the predictive nomogram. The performance of the nomogram was evaluated by calibration, discrimination and clinical usefulness. Differentiation, computed tomography (CT)-based on N stage (CT N stage), hemameba and tumor distance from the anus (cm) were integrated into the nomogram. The nomogram exhibited good discrimination, with an area under the curve (AUC) of 0.731 and good calibration. Application of the nomogram in the validation cohort showed acceptable discrimination, with an AUC of 0.710 and good calibration. Decision curve analysis revealed that the nomogram was clinically useful. These findings suggests, to the best of our knowledge, that this may be the first nomogram for individual preoperative prediction of VI in patients with CRC, which may promote preoperative optimization strategies for this selected group of patients.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Effects of curcumin on hypoxia-inducible factor as a new therapeutic target

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that consists of two subunits, the HIF-1α and HIF-1β (ARNT). Under hypoxic conditions, HIF-1 is an adaptive system that regulates the transcription of multiple genes associated with growth, angiogenesis, proliferation, glucose transport, metabolism, pH regulation and cell death. However, aberrant HIF-1 activation contributes to the pathophysiology of several human diseases such as cancer, ischemic cardiovascular disorders, and pulmonary and kidney diseases. A growing body of evidence indicates that curcumin, a natural bioactive compound of turmeric root, significantly targets both HIF-1 subunits, but is more potent against HIF-1α. In this review, we have summarized the knowledge about the pharmacological effects of curcumin on HIF-1 and the related molecular mechanisms that may be effective candidates for the development of multi-targeted therapy for several human diseases.

Role of adenosine signaling in the pathogenesis of head and neck cancer

The concentrations of adenosine may increase under ischemic conditions in the tumor microenvironment, and then it enters the systemic circulation. Adenosine controls cancer progression and responses to therapy by regulating angiogenesis, cell survival, apoptosis, cell proliferation, and metastases in tumors. Hence, adenosine metabolism, adenosine-generating enzymes, and adenosine signaling are potentially novel therapeutic targets in a wide range of pathological conditions, including cerebral and cardiac ischemic diseases, inflammatory disorders, immunomodulatory disorders, and, of special interest in this review, cancer. This review summarizes the role of adenosine in the pathogenesis of head and neck cancer for a better understanding of how this may be applied to treating this type of cancer.

Mechanisms and Therapy for Cancer Metastasis to the Brain

Advances in chemotherapy and targeted therapies have improved survival in cancer patients with an increase of the incidence of newly diagnosed brain metastases (BMs). Intracranial metastases are symptomatic in 60–70% of patients. Magnetic resonance imaging (MRI) with gadolinium is more sensitive than computed tomography and advanced neuroimaging techniques have been increasingly used in the detection, treatment planning, and follow-up of BM. Apart from the morphological analysis, the most effective tool for characterizing BM is immunohistochemistry. Molecular alterations not always reflect those of the primary tumor. More sophisticated methods of tumor analysis detecting circulating biomarkers in fluids (liquid biopsy), including circulating DNA, circulating tumor cells, and extracellular vesicles, containing tumor DNA and macromolecules (microRNA), have shown promise regarding tumor treatment response and progression. The choice of therapeutic approaches is guided by prognostic scores (Recursive Partitioning Analysis and diagnostic-specific Graded Prognostic Assessment-DS-GPA). The survival benefit of surgical resection seems limited to the subgroup of patients with controlled systemic disease and good performance status. Leptomeningeal disease (LMD) can be a complication, especially in posterior fossa metastases undergoing a “piecemeal” resection. Radiosurgery of the resection cavity may offer comparable survival and local control as postoperative whole-brain radiotherapy (WBRT). WBRT alone is now the treatment of choice only for patients with single or multiple BMs not amenable to surgery or radiosurgery, or with poor prognostic factors. To reduce the neurocognitive sequelae of WBRT intensity modulated radiotherapy with hippocampal sparing, and pharmacological approaches (memantine and donepezil) have been investigated. In the last decade, a multitude of molecular abnormalities have been discovered. Approximately 33% of patients with non-small cell lung cancer (NSCLC) tumors and epidermal growth factor receptor mutations develop BMs, which are targetable with different generations of tyrosine kinase inhibitors (TKIs: gefitinib, erlotinib, afatinib, icotinib, and osimertinib). Other “druggable” alterations seen in up to 5% of NSCLC patients are the rearrangements of the “anaplastic lymphoma kinase” gene TKI (crizotinib, ceritinib, alectinib, brigatinib, and lorlatinib). In human epidermal growth factor receptor 2-positive, breast cancer targeted therapies have been widely used (trastuzumab, trastuzumab-emtansine, lapatinib-capecitabine, and neratinib). Novel targeted and immunotherapeutic agents have also revolutionized the systemic management of melanoma (ipilimumab, nivolumab, pembrolizumab, and BRAF inhibitors dabrafenib and vemurafenib).

The 9p21 locus as a potential therapeutic target and prognostic marker in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related-death worldwide. Despite extensive efforts to identify valid biomarkers for the risk stratification of CRC patients, there are few of proven clinical utility. It is recognized that genetic factors play a major role in determining susceptibility to CRC. Recent genome-wide association studies have demonstrated common genetic variants in a region on chromosome 9p21 associated with an increased risk of CRC. Several genetic polymorphisms have been identified in this region that are associated with CRC. Three genes are located at this locus; CDKN2B(encoding-p15ink4b), CDKN2A (encoding-p16ink4a/p14ARF) and 3′ end of CDKN2BAS (termed-antisense-noncoding-RNA in the INK4-locus [ANRIL]). ANRIL has a post-transcriptional modulatory activity, which has been shown to perturb the expression of nearby genes. It also plays an important role in coordinating tissue remodeling through regulation of cell proliferation, apoptosis, aging, extra-cellular matrix remodeling and inflammatory response. However, the role of ANRIL is not well understood in CRC. Hypermethylation of the p14ARF and p16INK4a genes is often found in some tumors, including CRC. However, further studies are necessary to explore the clinical utility of these putative markers in risk stratification, and in the assessment of prognosis. In this review, we have summarized the prognostic and therapeutic potential of the p14ARF and p16INK4a genes in patients with colorectal cancer.

Current Strategies to Enhance Anti-Tumour Immunity

The interaction of the immune system with cancer is complex, but new approaches are resulting in exciting therapeutic benefits. In order to enhance the immune response to cancer, immune therapies seek to either induce high avidity immune responses to tumour specific antigens or to convert the tumour to a more pro-inflammatory microenvironment. Strategies, including vaccination, oncolytic viruses, and adoptive cell transfer all seek to induce anti-tumour immunity. To overcome the suppressive tumour microenvironment checkpoint inhibitors and modulators of regulatory cell populations have been investigated. This review summarizes the recent advances in immune therapies and discusses the importance of combination therapies in the treatment of cancers.

The Therapeutic Potential of PI3K/Akt/mTOR Inhibitors in Breast Cancer: Rational and Progress

Breast cancer (BC) is the most commonly diagnosed cancer in women. The PI3K/AKT/mTOR pathway is among the most frequently dysregulated pathways in patients with BC. The activation of this pathway is associated with increased cell growth and clinical outcome, and its overexpression is associated with a poor prognosis. It has been proposed that it may be of importance as a potential therapeutic target in the treatment of BC. The aim of current review is to provide an overview of the potential utility of PI3K/Akt/mTOR inhibitors in patients with BC, with particular emphasis on recent preclinical and clinical studies. J. Cell. Biochem. 119: 213-222, 2018. © 2017 Wiley Periodicals, Inc.

Genetic Background of Hirschsprung Disease: A Bridge Between Basic Science and Clinical Application

Hirschsprung's disease (HSCR) is a congenital disorder, defined by partial or complete loss of the neuronal ganglion cells in the intestinal tract, which is caused by the failure of neural crest cells to migrate completely during intestinal development during fetal life. HSCR has a multifactorial etiology, and genetic factors play a key role in its pathogenesis; these include mutations within several gene loci. These have been identified by screening candidate genes, or by conducting genome wide association (GWAS) studies. However, only a small portion of them have been proposed as major genetic risk factors for the HSCR. In this review, we focus on those genes that have been identified as either low penetrant or high penetrant variants that determine the risk of Hirschsprung's disease. J. Cell. Biochem. 119: 28-33, 2018. © 2017 Wiley Periodicals, Inc.