Haofan Yin

Significance CRC patients with KRAS mutations are confronted with limited targeted therapeutic options. In this study, we have shown that the median survival time for KRAS -mutation mCRC patients with diabetes on metformin is 37.8 mo longer than those treated with other hypoglycemic drugs in combination with standard systemic therapy. Metformin is preferentially accumulated in KRAS -mutation CRC cells in both primary cell cultures and patient-derived xenografts. The promising therapeutic activity of metformin has a negative correlation with MATE1 expression, which is proven to eliminate metformin from CRC cells. These findings indicate that KRAS -mutation mCRC patients could benefit from metformin treatment, and somatic KRAS status or MATE1 expression should be recommended to predict the therapeutic response of metformin in CRC.

The potential of serum extracellular vesicles (EVs) as non-invasive biomarkers for diagnosing colorectal cancer (CRC) remains elusive. We employed an in-depth 4D-DIA proteomics and machine learning (ML) pipeline to identify key proteins, PF4 and AACT, for CRC diagnosis in serum EV samples from a discovery cohort of 37 cases. PF4 and AACT outperform traditional biomarkers, CEA and CA19-9, detected by ELISA in 912 individuals. Furthermore, we developed an EV-related random forest (RF) model with the highest diagnostic efficiency, achieving AUC values of 0.960 and 0.963 in the train and test sets, respectively. Notably, this model demonstrated reliable diagnostic performance for early-stage CRC and distinguishing CRC from benign colorectal diseases. Additionally, multi-omics approaches were employed to predict the functions and potential sources of serum EV-derived proteins. Collectively, our study identified the crucial proteomic signatures in serum EVs and established a promising EV-related RF model for CRC diagnosis in the clinic. • 4D-DIA proteomic profiles of serum EVs in CRC patients and healthy controls • Identification of proteomic signatures in serum EVs for CRC diagnosis • Development of diagnostic model distinguishing CRC from healthy controls and BCD • Prediction of functions and potential cell sources of serum EV-derived proteins Yin et al. utilizes 4D-DIA proteomics and machine learning to identify key biomarkers PF4 and AACT in serum extracellular vesicles for colorectal cancer (CRC) diagnosis. Their random forest model demonstrates superior diagnostic performance for early-stage CRC and distinguishing CRC from benign colorectal diseases, offering a promising tool for clinical application.

Distant metastasis is, unfortunately, the leading cause of death in colorectal cancer (CRC). Approximately 50% of CRC patients develop liver metastases, while 10-30% of patients develop pulmonary metastases. The occurrence of metastasis is considered to be almost exclusively driven by cancer stem cells (CSCs) formation. However, the key molecules that confer the transformation to stem cells in CRC, and subsequent metastasis, remain unclear. Far upstream element-binding protein 1 (FUBP1), a transcriptional regulator of c-Myc, was screened in CSCs of CRC by mass spectrometry and was examined by immunohistochemistry in a cohort of CRC tissues. FUBP1 was upregulated in 85% of KRAS-mutant and 25% of wild-type CRC patients. Further, whether in KRAS-mutant or wild-type patients, elevated FUBP1 was positively correlated with CRC lymph node metastasis and clinical stage, and negatively associated with overall survival. Overexpression of FUBP1 significantly enhanced CRC cell migration, invasion, tumor sphere formation, and CD133 and ALDH1 expression in vitro, and tumorigenicity in vivo. Mechanistically, FUBP1 promoted the initiation of CSCs by activating Wnt/β-catenin signaling via directly binding to the promoter of DVL1, a potent activator of β-catenin. Knockdown of DVL1 significantly inhibited the transformation to stem cells in, as well as the tumorigenicity of, CRC. Activation of Wnt/β-catenin signaling by DVL1 increased pluripotent transcription factors, including c-Myc, NANOG, and SOX2. Moreover, FUBP1 was upregulated at the post-transcriptional level. Elevated FUBP1 levels in KRAS wild-type CRC patients is due to the decrease in Smurf2, which promotes ubiquitin-mediated degradation of FUBP1. In contrast, FUBP1 was upregulated in KRAS-mutant patients through both inhibition of caspase 3-dependent cleavage and decreased Smurf2. Our results demonstrate, for the first time, that FUBP1 is an oncogene, initiating the development of CSCs, as well as a new powerful endogenous Wnt-signaling agonist that could provide an important prognostic factor and therapeutic target for metastasis in both KRAS-mutant and wild-type CRC.

Gastric cancer is one of the most malignant tumor types, and its metastasis is a notable cause of mortality. Among the methods of tumor metastasis, lymphatic metastasis is the predominant one in gastric cancer. A previous study reported that the plasma oxidized low‑density lipoprotein (oxLDL) is the risk factor associated with the development of tumors in patients with abnormal lipid metabolism, but the influence of plasma oxLDL in the lymphatic metastasis of gastric cancer remains unclear. In the present study, the concentration of plasma oxLDL from patients with gastric cancer was detected with an ELISA kit, and the lymphatic vessel density in gastric cancer tissues was determined by D2‑40 staining. The correlation analysis of oxLDL concentration and lymphatic vessel density demonstrated that plasma oxLDL was positively correlated with lymphatic metastasis in patients with gastric cancer. Subsequently, the popliteal lymph node metastasis animal experiment with nude mice confirmed that oxLDL could promote the lymphatic metastasis of gastric cancer. Following this, the western blotting and ELISA data demonstrated that oxLDL promoted the expression and secretion of vascular endothelia growth factor (VEGF)‑C in gastric cancer cell lines. Finally, blocking the lectin‑like oxLDL‑1 (LOX‑1) receptor, a specific receptor for oxLDL, and the nuclear factor (NF)‑κB signaling pathway following oxLDL (50 µg/ml) treatment in HGC‑27 cells revealed that oxLDL could activate the NF‑κB signaling pathway mediated by LOX‑1, with subsequent upregulation of VEGF‑C expression, and secretion in and from gastric cancer cells, and finally that it could promote the lymphatic metastasis of gastric cancer. These data indicate the association between the plasma oxLDL and the lymphatic metastasis of gastric cancer, and indicate that oxLDL elimination may be a potential therapeutic target for the prevention and intervention of early lymph node metastasis in gastric cancer.

Circular RNA (circRNA) and microRNA (miRNA) are both non-coding RNAs (ncRNAs) that serve as biomarkers for cancer diagnosis and prognosis. Quantitative detection of these ncRNAs is of particular importance to elucidate the functional mechanisms and evaluate their potential as biomarkers. However, the inherent structures of circRNA and miRNA are different from the mRNA, conventional qRT-PCR is unsuitable for the detection of these ncRNAs. Here, we propose a sensitive method for quantitative detection of circRNA and miRNA using polydisperse droplet digital CRISPR/Cas13a (PddCas13a). It can achieve limits of detection (LOD) as low as ∼10 aM without polymerase-based amplification. To efficiently detect the circRNA and miRNA in real samples, we use a chemically modified crRNA to enhance the stability of crRNA and improve the performance of Cas13a in complex environments containing contaminants. By integrating an extraction-free procedure with PddCas13a, we experimentally demonstrate the applicability of PddCas13a by testing clinical samples. Furthermore, we develop an automated and portable instrument for PddCas13a and verify its applicability for the detection of circRNA and miRNA from exosomes in point-of-care (POC) setting. This is the first report to detect the circRNA and miRNA simultaneously in POC setting. We envision this platform could promote the research of ncRNAs. • PddCas13a can detect the circRNA and miRNA directly as low as 10 aM without the polymerase-based amplification. • By using chemically modified crRNA, PddCas13a can detect the circRNA and miRNA in complex environments containing contaminants. • We developed an automated and portable instrument for PddCas13a in point-of-care (POC) setting.