Novel Genetic and Epigenetic Biomarkers of Prognostic and Predictive Significance in Stage II/III Colorectal Cancer.

The therapeutic strategies of stage II/III colorectal cancer (CRC) patients after curative surgery remain controversial. In the clinical decision-making process, oncologists need to answer questions such as whether adjuvant chemotherapy is necessary or which therapeutic regimen should be given to each patient. At present, whether adjuvant chemotherapy should be applied is primarily based on histopathological features and clinical risk factors. However, only a fraction of patients can benefit from it. More rigorous stratifying biomarkers are urgently needed to help further distinguishing these populations of patients. Recent progress in next-generation sequencing and high-throughput technologies has greatly promoted biomarker discovery as well as our understanding of the underlying mechanisms in CRC. Novel genetic and epigenetic biomarkers that are associated with prognosis or therapeutic responses have emerged. In this review, we discuss the strategies of biomarker discovery and summarize the status and assess the utility of previously published biomarkers in CRC.

The Macrophage-Associated LncRNA MALR Facilitates ILF3 Liquid-Liquid Phase Separation to Promote HIF1α Signaling in Esophageal Cancer.

SIGNIFICANCE: Secretion of TNFα by tumor-associated macrophages stimulates cancer cells to upregulate lncRNA MALR, which induces ILF3 liquid-liquid phase separation and activation of HIF1α signaling to promote cancer progression.

Glucose metabolism inhibitor PFK-015 combined with immune checkpoint inhibitor is an effective treatment regimen in cancer.

Metabolic inhibition via PFKFB3 inhibition has demonstrated considerable tumor inhibitory effects in various studies; however, PFKFB3 inhibition did not show satisfactory tumor inhibition when used in clinical trials. PFKFB3 is a crucial metabolic enzyme that is highly upregulated in cancer cells and directly affects tumor glycolysis. Here, we showed that PFKFB3 inhibition suppresses tumors in vitro and in vivo in immune-deficient xenografts. However, this inhibition induces the upregulation of PD-L1 levels, which inactivated cocultured T-cells in vitro, compromises anti-tumor immunity in vivo, and reduced anti-tumor efficacy in an immune-competent mouse model. Functionally, PD-1 mAb treatment enhances the efficacy of PFKFB3 inhibition in immunocompetent and hu-PBMC NOG mouse models. Mechanistically, PFKFB3 inhibition increases phosphorylation of PFKFB3 at residue Ser461, which increases interaction with HIF-1α, and their colocalization into the nucleus, where HIF-1α transcriptionally upregulate PD-L1 expression and causes subsequent tumor immune evasion. Higher phos-PFKFB3 correlated with higher PD-L1 expression, lower CD8 and GRZMB levels, and shorter survival time in ESCC patients.

LncRNA TMPO-AS1 promotes esophageal squamous cell carcinoma progression by forming biomolecular condensates with FUS and p300 to regulate TMPO transcription.

Esophageal squamous cell carcinoma (ESCC) is one of the most life- and health-threatening malignant diseases worldwide, especially in China. Long noncoding RNAs (lncRNAs) have emerged as important regulators of tumorigenesis and tumor progression. However, the roles and mechanisms of lncRNAs in ESCC require further exploration. Here, in combination with a small interfering RNA (siRNA) library targeting specific lncRNAs, we performed MTS and Transwell assays to screen functional lncRNAs that were overexpressed in ESCC. TMPO-AS1 expression was significantly upregulated in ESCC tumor samples, with higher TMPO-AS1 expression positively correlated with shorter overall survival times. In vitro and in vivo functional experiments revealed that TMPO-AS1 promotes the proliferation and metastasis of ESCC cells. Mechanistically, TMPO-AS1 bound to fused in sarcoma (FUS) and recruited p300 to the TMPO promoter, forming biomolecular condensates in situ to activate TMPO transcription in cis by increasing the acetylation of histone H3 lysine 27 (H3K27ac). Targeting TMPO-AS1 led to impaired ESCC tumor growth in a patient-derived xenograft (PDX) model. We found that TMPO-AS1 is required for cell proliferation and metastasis in ESCC by promoting the expression of TMPO, and both TMPO-AS1 and TMPO might be potential biomarkers and therapeutic targets in ESCC.

MYC-Activated LncRNA MNX1-AS1 Promotes the Progression of Colorectal Cancer by Stabilizing YB1.

Long noncoding RNAs (lncRNA) are involved in tumorigenesis and drug resistance. However, the roles and underlying mechanisms of lncRNAs in colorectal cancer are still unknown. In this work, through transcriptomic profiling analysis of 21 paired tumor and normal samples, we identified a novel colorectal cancer-related lncRNA, MNX1-AS1. MNX1-AS1 expression was significantly upregulated in colorectal cancer and associated with poor prognosis. In vitro and in vivo gain- and loss-of-function experiments showed that MNX1-AS1 promotes the proliferation of colorectal cancer cells. MNX1-AS1 bound to and activated Y-box-binding protein 1 (YB1), a multifunctional RNA/DNA-binding protein, and prevented its ubiquitination and degradation. A marked overlap between genes that are differentially expressed in MNX1-AS1 knockdown cells and transcriptional targets of YB1 was observed. YB1 knockdown mimicked the loss of viability phenotype observed upon depletion of MNX1-AS1. In addition, MYC bound the promoter of the MNX1-AS1 locus and activated its transcription. In vivo experiments showed that ASO inhibited MNX1-AS1, which suppressed the proliferation of colorectal cancer cells in both cell-based and patient-derived xenograft models. Collectively, these findings suggest that the MYC-MNX1-AS1-YB1 axis might serve as a potential biomarker and therapeutic target in colorectal cancer. SIGNIFICANCE: This study highlights the discovery of a novel colorectal cancer biomarker and therapeutic target, MNX1-AS1, a long noncoding RNA that drives proliferation via a MYC/MNX1-AS1/YB1 signaling pathway. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/10/2636/F1.large.jpg.

The lncRNA XIST/miR-125b-2-3p axis modulates cell proliferation and chemotherapeutic sensitivity via targeting Wee1 in colorectal cancer.

BACKGROUND: Numerous reports on microRNAs have illustrated their role in tumor growth and metastasis. Recently, a new prognostic factor, miR-125b-2-3p, has been identified for predicting chemotherapeutic sensitivity in advanced colorectal cancer (CRC). However, the specific mechanisms and biological functions of miR-125b-2-3p in advanced CRC under chemotherapy have yet to be elucidated. METHODS: MiR-125b-2-3p expression was detected by real-time PCR (RT-PCR) in CRC tissues. The effects of miR-125b-2-3p on the growth, metastasis, and drug sensitivity of CRC cells were tested in vitro and in vivo. Based on multiple databases, the upstream competitive endogenous RNAs (ceRNAs) and the downstream genes for miR-125b-2-3p were predicted by bioinformatic analysis, followed by the experiments including luciferase reporter assays, western blot assays, and so on. RESULTS: MiR-125b-2-3p was significantly lowly expressed in the tissues and cell lines of CRC. Higher expression of miR-125b-2-3p was associated with relatively lower proliferation rates and fewer metastases. Moreover, overexpressed miR-125b-2-3p remarkably improved chemotherapeutic sensitivity of CRC in vivo and in vitro. Mechanistically, miR-125b-2-3p was absorbed by long noncoding RNA (lncRNA) XIST regulating WEE1 G2 checkpoint kinase (WEE1) expression. The upregulation of miR-125b-2-3p inhibited the proliferation and epithelial-mesenchymal transition (EMT) of CRC induced by lncRNA XIST. CONCLUSIONS: Lower miR-125b-2-3p expression resulted in lower sensitivity of CRC to chemotherapy and was correlated with poorer survival of CRC patients. LncRNA XIST promoted CRC metastasis acting as a ceRNA for miR-125b-2-3p to mediate WEE1 expression. LncRNA XIST-miR-125b-2-3p-WEE1 axis not only regulated CRC growth and metastasis but also contributed to chemotherapeutic resistance to CRC.