Knockdown of Hypoxia-Inducible Factor 1α Improved the Efficacy of Low-Dose Metronomic Chemotherapy of Paclitaxel in Human Colon Cancer Xenografts

The Mixture of Ferulic Acid and P-Coumaric Acid Suppresses Colorectal Cancer through lncRNA 495810/PKM2 Mediated Aerobic Glycolysis

Polyphenol-rich foods are gaining popularity due to their potential beneficial effects in the prevention and treatment of cancer. Foxtail millet is one of the important functional foods, riches in a variety of biologically active substance. Our previous study showed that ferulic acid (FA) and p-coumaric acid (p-CA) are the main anticancer components of foxtail millet bran, and the two have a significant synergistic effect. In the present study, the clinical application potential of FA and p-CA (FA + p-CA) were evaluated in vivo and in vitro. The FA and p-CA target gene enrichment analysis discovered that FA + p-CA were associated with aerobic glycolysis. It was further shown that FA + p-CA remodel aerobic glycolysis by inhibiting the glycolysis-associated lncRNA 495810 and the glycolytic rate-limiting enzyme M2 type pyruvate kinase (PKM2). Moreover, PKM2 expression was positively correlated with lncRNA 495810. More interestingly, the exogenous expression of lncRNA 495810 eliminated the inhibitory effects of FA + p-CA on aerobic glycolysis. Collectively, FA + p-CA obstruct the aerobic glycolysis of colorectal cancer cells via the lncRNA 495810/PKM2 axis, which provides a nutrition intervention and treatment candidate for colorectal cancer.

The interactions of paclitaxel with tumour microenvironment

Today, it is well-known that the interactions and secretion within the tumour are crucial to consider for cancer therapy. Some novel cancer therapy modalities such as immunotherapy or tumour vaccination therapy work based on the control of interactions within the tumour microenvironment (TME). It has been revealed that anti-cancer drugs or radiotherapy can modulate some interactions in favour of cancer therapy. However, they may induce some mechanisms to increase the resistance of cancer cells to therapy. Paclitaxel is known as the first approved herbal derived chemotherapy drug. Although the main known anti-cancer effect of paclitaxel is the inhibition of the cell cycle, today, it has been well known that paclitaxel may suppress the tumour via modulating several interactions in TME. Furthermore, paclitaxel may increase the expression of some tumour resistance drivers. This review aims to discuss the interactions within TME following treatment with paclitaxel. The effects of paclitaxel on the anti-tumour immunity, immunosuppressive cells, hypoxia, and also angiogenesis will be discussed. The targeting of these interactions may be interesting to increase therapy efficiency using the combination modalities.

Effect of rs67085638 in long non-coding RNA (CCAT1) on colon cancer chemoresistance to paclitaxel through modulating the microRNA-24-3p and FSCN1

It has been reported that rs67085638 in long non-coding RNAs (lncRNA)-CCAT1 was associated with the risk of tumorigenesis. Also, CCAT1 could affect chemoresistance of cancer cells to paclitaxel (PTX) via regulating miR-24-3p and FSCN1 expression. In this study, we aimed to investigate the effect of rs67085638 on the expression of CCAT1/miR-24-3p/FSCN1 and the response of colon cancer to the treatment of PTX. 48 colon cancer patients were recruited and grouped by their genotypes of rs67085638 polymorphism as a CC group (N = 28) and a CT group (N = 20). PCR analysis, IHC assay and Western blot, TUNEL assay and flow cytometry were conducted. LncRNA-CCAT1 and FSCN1 mRNA/protein were overexpressed, whereas miR-24-3p was down-regulated in the CT-genotyped patients and cells compared with those in the CC-genotyped patients and cells. The survival of colon cancer cells was decreased, whereas the apoptosis of colon cancer cells was increased by PTX treatment in a dose-dependent manner. MiR-24-3p was validated to target lncRNA-CCAT1 and FSCN1 mRNA, and the overexpression of CCAT1 could reduce the expression of miR-24-3p although elevating the expression of FSCN1. Knockdown of lncRNA-CCAT1 partly reversed the suppressed growth of CT-genotyped tumours. And the knockdown of lncRNA-CCAT1 partly reversed the dysregulation of lncRNA-CCAT1 and FSCN1 mRNA/protein in rs67085638-CT + NC shRNA mice. The findings of this study demonstrated that the presence of the minor allele of rs67085638 increased the expression of CCAT1 and accordingly enhanced the resistance to PTX. Down-regulation of CCAT1 significantly re-stored the sensitivity to PTX of colon cancer cells.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.

Long noncoding RNA FEZF1-AS1 predicts poor prognosis and modulates pancreatic cancer cell proliferation and invasion through miR-142/HIF-1α and miR-133a/EGFR upon hypoxia/normoxia

Nowadays, pancreatic cancer (PC) remains the most lethal tumor, partially due to the invasive and treatment-resistant phenotype induced by the extent of hypoxic stress within the tumor tissue. According to previous studies, miR-142/HIF-1α and miR-133a/EGFR could modulate PC cell proliferation under hypoxic and normoxic conditions, respectively. In the present study, FEZF1-AS1, a recently described oncogenic long noncoding RNA, was predicted to target both miR-142 and miR-133a; thus, we hypothesized that FEZF1-AS1 might affect PC cell proliferation through these two axes under hypoxic or normoxic conditions. In PC cell lines, FEZF1-AS1 acted as an oncogene via promoting PC cell proliferation and invasion through miR-142/HIF-1α axis under hypoxic condition; however, FEZF1-AS1 failed to affect the protein levels of HIF-1α and VEGF under the normoxic condition, suggesting the existence of another signaling pathway under normoxic condition. As predicted by an online tool, FEZF1-AS1 could target miR-133a to inhibit its expression; under the normoxic condition, FEZF1-AS1 exerted its effect on PC cell lines through miR-133a/EGFR axis. Taken together, FEZF1-AS1 might be a promising target in controlling the aberrant proliferation and invasion of PC cell lines.

Rationale for the use of metronomic chemotherapy in gastrointestinal cancer

INTRODUCTION

Metronomic chemotherapy (mCT) is endowed with various properties, ranging from antiangiogenic to immunomodulation, and may revert tumor resistance to conventional drug administration. A variety of antineoplastic agents displayed activity when administered with metronomic schedules in preclinical models of gastrointestinal cancers. However, most of the field is still unexplored.

AREAS COVERED

Herein, the authors review the existing literature from PubMed, concerning the use of mCT in gastrointestinal oncology.

EXPERT OPINION

A mounting body of evidence is emerging in support of mCT as a treatment option for gastrointestinal tumors, but the frequent signs of clinical activity inconsistently translate into a benefit for survival. Research in this field should focus on providing high-quality evidence on the safety and efficacy of mCT, with more prospective, comparative trials; identifying the subgroups of patients for whom mCT would be the best approach; establishing standardized protocols based on mCT pharmacokinetics and pharmacodynamics; developing drug activity biomarkers. mCT is also potentially suitable for combinations with targeted antiangiogenic drugs and may be incorporated with conventional administration into dual regimens.

mRNA-miRNA bipartite network reconstruction to predict prognostic module biomarkers in colorectal cancer stage differentiation

Biomarker detection is one of the most important and challenging problems in cancer studies. Recently, non-coding RNA based biomarkers such as miRNA expression levels have been used for early diagnosis of many cancer types. In this study, a systems biology approach was used to detect novel miRNA based biomarkers for CRC diagnosis in early stages. The mRNA expression data from three CRC stages (Low-grade Intraepithelial Neoplasia (LIN), High-grade Intraepithelial Neoplasia (HIN) and Adenocarcinoma) were used to reconstruct co-expression networks. The networks were clustered to extract co-expression modules and detected low preserved modules among CRC stages. Then, the experimentally validated mRNA-miRNA interaction data were applied to reconstruct three mRNA-miRNA bipartite networks. Twenty miRNAs with the highest degree (hub miRNAs) were selected in each bipartite network to reconstruct three bipartite subnetworks for further analysis. The analysis of these hub miRNAs in the bipartite subnetworks revealed 30 distinct important miRNAs as prognostic markers in CRC stages. There are two novel CRC related miRNAs (hsa-miR-190a-3p and hsa-miR-1277-5p) in these 30 hub miRNAs that have not been previously reported in CRC. Furthermore, a drug-gene interaction network was reconstructed to detect potential candidate drugs for CRC treatment. Our analysis shows that the hub miRNAs in the mRNA-miRNA bipartite network are very essential in CRC progression and should be investigated precisely in future studies. In addition, there are many important target genes in the results that may be critical in CRC progression and can be analyzed as therapeutic targets in future research.