CircNOLC1 Promotes Colorectal Cancer Liver Metastasis by Interacting with AZGP1 and Sponging miR-212-5p to Regulate Reprogramming of the Oxidative Pentose Phosphate Pathway

Unlocking the lipid code: SREBPs as key drivers in gastrointestinal tumour metabolism

In recent years, metabolic reprogramming has emerged as a significant breakthrough in elucidating the onset and progression of gastrointestinal (GI) malignancies. As central regulatory hubs for lipid metabolism, sterol regulatory element binding proteins (SREBPs) integrate dietary metabolic signals and carcinogenic stimuli through subtype-specific mechanisms, thereby promoting malignant tumour phenotypes. In this review, we first present the molecular background, structural characteristics, and posttranscriptional regulatory networks associated with SREBPs. We subsequently describe a systematic analysis of the distinct activation patterns of SREBPs in liver, gastric, colorectal, and other gastrointestinal cancers. Furthermore, we explore targeted intervention strategies for different SREBP subtypes, including small molecule inhibitors (such as fatostatin, which inhibits SREBP cleavage), natural compounds (such as berberine, which modulates the AMPK/mTOR pathway), and statin-mediated inhibition of the mevalonic acid pathway. These strategies may enhance tumour cell sensitivity to chemotherapeutic agents (such as 5-FU, gezil, and tabine) and improve the response to synergistic chemoradiotherapy by reversing adaptive metabolic resistance driven by the tumour microenvironment. Through this review, we hope to provide new insights into precise interventions targeting various subtypes of the SREBP molecule.

Kaempferol Induces DNA Damage in Colorectal Cancer Cells by Regulating the MiR-195/miR-497-PFKFB4-Mediated Nonoxidative Pentose Phosphate Pathway

Kaempferol is a flavonoid widely found in fruits and vegetables. Our previous studies have shown that kaempferol has a good inhibitory effect on colorectal cancer in vitro and in vivo, significantly inhibiting proliferation and inducing cycle arrest and apoptosis. The pentose phosphate pathway (PPP) is a branch of glucose catabolism, that provides the raw material ribose-5-phosphate (R5P) for biosynthesis for the rapid proliferation of tumor cells and is closely related to DNA damage. DNA damage has been shown to play an important role in cell cycle arrest and apoptosis. Therefore, we speculate whether kaempferol exerts the antitumor effect by inducing DNA damage. Herein we actually found that kaempferol treatment induced DNA damage, as indicated by increased γH2AX expression and comet assay. Furthermore, kaempferol reduced R5P production by inhibiting the nonoxidative PPP, while supplementation with nucleosides rescued DNA damage. Mechanistically, kaempferol upregulates the expression of microRNA-195/497 (miR-195/497) and then suppresses PFKFB4 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4) expression by directly binding to its 3'-UTR, thereby inhibiting the expression of transketolase (TKT) and transaldolase (TALDO), key enzymes in the nonoxidative PPP. These data uncover new targets and pathways for the action of kaempferol and lay the foundation for its development as an adjuvant drug for the treatment of colorectal cancer.

The Prognostic Significance and Co-Expression of Fibroblast Growth Factor Receptor 2 and c-Met in Endometrial Cancer

Objective

We sought to study the expression of FGFR2 and c-Met and evaluate the correlation between the two proteins in a series of endometrial cancer patients as well as the prognostic significance of the two markers in endometrium carcinoma.

Methods

Patients who were diagnosed with endometrial cancer and had undergone surgical treatment in Beijing Chao-Yang Hospital, Capital Medical University from November 2004 to June 2011 were included in this study. Tissue microarray construction, immunohistochemical staining and scoring were employed to study the expression of FGFR2 and c-Met. SPSS version 22.0 was used to evaluate the correlation between FGFR2 and c-Met expression and the prognosis prediction value of the two markers.

Results

In total, 109 patients were included in this study. The median age was 56 years (ranges, 30-79). The most common histologic tumor subtype was adenocarcinoma (86.2%). The five-year survival rate was 87.2%. Significantly different FGFR2 expression was observed among patients with different disease stages (p < 0.001), depths of myometrial invasion (p = 0.001) and lymph node status (p < 0.001). C-Met expression was also increased in tissues from patients with advanced stage disease, deep myometrial invasion and lymph node metastasis (p < 0.001, p = 0.031 and p < 0.001, respectively). The expression of FGFR2 and c-Met was increased in the group with poorer prognosis (overall survival < 5 years) (p = 0.002 and p = 0.023, respectively). Moreover, a strong positive correlation was observed between FGFR2 and c-Met expression (p < 0.01, r = 0.656). FGFR2 was a significant factor that influence the FIGO stage.

Conclusion

Higher expression of FGFR2 and c-Met is associated with more advanced stage, deeper myometrial invasion and lymph node metastasis in endometrial cancer and poorer prognosis. In addition, high expression of FGFR2 is correlated with high c-Met expression.

circEIF3I Promotes Colorectal Cancer Metastasis by Regulating the miR-328-3p/NCAPH Axis

Colorectal cancer (CRC) is the most common gastrointestinal malignancy, with its recurrence and metastasis significantly affecting patient survival. Circular RNAs (circRNAs), a novel class of noncoding RNAs, have emerged as crucial contributors to CRC pathogenesis. However, the role of circEIF3I in CRC metastasis remains unclear. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to assess circEIF3I, microRNA (miR)-328-3p, and NCAPH expression. CRC cell migration and invasion were determined via Transwell assays. Western blot analysis was utilized to define the protein expression of epithelial-mesenchymal transition (EMT) markers and NCAPH. Xenograft tumor was established for exploration into the function of circEIF3I in CRC metastasis to the liver and lung. The binding between miR-328-3p and circEIF3I or NCAPH was predicted through ENCORI or TargetScan platform and ascertained through dual-luciferase reporter assays. circEIF3I and NCAPH expression were found to be elevated in CRC tissues and cells, while miR-328-3p was downregulated. Functionally, circEIF3I knockdown inhibited CRC cell migration, invasion, EMT, and tumor metastasis. Mechanistic analyses revealed that circEIF3I can target miR-328-3p, while NCAPH was targeted by miR-328-3p. Furthermore, circEIF3I facilitated NCAPH expression in CRC cells by sequestering miR-328-3p. Notably, miR-328-3p inhibitor or NCAPH overexpression negated the effects of circEIF3I knockdown on preventing CRC progression in vitro. Taken together, circEIF3I elevated NCAPH expression by sponging miR-328-3p, thereby promoting CRC metastasis. These findings suggest that the circEIF3I/miR-328-3p/NCAPH axis represents a novel therapeutic target for CRC.

A Novel 167-Amino Acid Protein Encoded by CircPCSK6 Inhibits Intrahepatic Cholangiocarcinoma Progression via IKBα Ubiquitination

Intrahepatic cholangiocarcinoma (ICC), a formidable challenge in oncology, demands innovative biomarkers and therapeutic targets. This research highlights the importance of the circular RNA (circRNA) circPCSK6 and its peptide derivative circPCSK6-167aa in ICC. CircPCSK6 is significantly downregulated in both ICC patients and mouse primary ICC models, and its lower expression is linked to adverse prognosis, highlighting its pivotal role in ICC pathogenesis. Functionally, this study elucidates the regulatory effect of circPCSK6-167aa on IκBα ubiquitination within the NF-κB pathway, which is mediated by its competitive binding to the E3 ligase RBBP6. This complex interaction leads to reduced activation of the NF-κB pathway, thereby curbing tumor cell proliferation, migration, invasion, stemness, and hepatic-lung metastasis in vivo. This groundbreaking discovery expands the understanding of circRNA-driven tumorigenesis through atypical signaling pathways. Additionally, this investigation identified EIF4A3 as a detrimental regulator of circPCSK6, exacerbating ICC malignancy. Importantly, by leveraging patient-derived xenograft (PDX), organoids, and organoid-derived PDX models, higher levels of circPCSK6-167aa enhance sensitivity to gemcitabine, indicating its potential to improve the effectiveness of chemotherapy. These insights emphasize the therapeutic promise of targeting circPCSK6-167aa, offering vital biological insights and clinical directions for developing cutting-edge therapeutic approaches, thus revealing innovative strategies and targets for future treatments.

The Pentose Phosphate Pathway: From Mechanisms to Implications for Gastrointestinal Cancers

The pentose phosphate pathway (PPP), traditionally recognized for its role in generating nicotinamide adenine dinucleotide phosphate (NADPH) and ribose-5-phosphate (R5P), has emerged as a critical metabolic hub with involvements in various gastrointestinal (GI) cancers. The PPP plays crucial roles in the initiation, development, and tumor microenvironment (TME) of GI cancers by modulating redox homeostasis and providing precursors for nucleotide biosynthesis. Targeting PPP enzymes and their regulatory axis has been a potential strategy in anti-GI cancer therapies. In this review, we summarize the regulatory mechanisms of PPP enzymes, elucidate the relationships between the PPP and TME's elements, and discuss the therapeutic potential of targeting the PPP in GI cancers.

YY1 downregulation underlies therapeutic response to molecular targeted agents

During targeted treatment, oncogene-addicted tumor cells often evolve from an initial drug-sensitive state through a drug-tolerant persister bottleneck toward the ultimate emergence of drug-resistant clones. The molecular basis underlying this therapy-induced evolutionary trajectory has not yet been completely elucidated. Here, we employed a multifaceted approach and implicated the convergent role of transcription factor Yin Yang 1 (YY1) in the course of diverse targeted kinase inhibitors. Specifically, pharmacological perturbation of the receptor tyrosine kinase (RTK)/mitogen-activated protein kinase (MAPK) pathway resulted in the downregulation of YY1 transcription, which subsequently resumed upon therapeutic escape. Failure to decrease YY1 subverted cytotoxic effects, whereas elimination of residual YY1 maximized anticancer efficacy and forestalled the emergence of drug resistance. Mechanistically, YY1 was uncovered to dictate cell cycle and autophagic programs. Immunohistochemical analysis on a wide spectrum of clinical specimens revealed that YY1 was ubiquitously expressed across lung adenocarcinomas and exhibited anticipated fluctuation in response to corresponding RTK/MAPK inhibition. These findings advance our understanding of targeted cancer management by highlighting YY1 as a determinant node in the context of genotype-directed agents.

m6A-modified circXPO1 accelerates colorectal cancer progression via interaction with FMRP to promote WWC2 mRNA decay

BACKGROUND

Recent evidence has demonstrated the vital roles of circular RNAs (circRNAs) in the progression of colorectal cancer (CRC); however, their functions and mechanisms in CRC need to be further explored. This study aimed to uncover the biological function of circXPO1 in CRC progression.

METHODS

CircXPO1 was identified by Sanger sequencing, RNase R, and actinomycin D treatment assays. Colony formation, scratch, transwell assays, and mouse xenograft models were adopted to evaluate CRC cell growth and metastasis in vitro and in vivo. Subcellular expression of circXPO1 was detected by FISH and nuclear-cytoplasmic separation assays. Molecular mechanisms were investigated by MeRIP, RIP, and RNA pull-down assays. Target molecular expression was detected by RT-qPCR, Western blotting and immunohistochemical staining.

RESULTS

circXPO1 was up-regulated in CRC tissues and cells, which indicated a poor prognosis of CRC patients. circXPO1 deficiency delayed the growth, EMT, and metastasis of CRC cells. Mechanistical experiments indicated that down-regulation of ALKBH5 enhanced IGF2BP2-mediated m6A modification of circXPO1 to increase circXPO1 expression. Furthermore, circXPO1 interacted with FMRP to reduce the mRNA stability of WWC2, which consequently resulted in Hippo-YAP pathway activation. Rescue experiments suggested that WWC2 overexpression abrogated circXPO1-mediated malignant capacities of CRC cells. The in vivo growth and liver metastasis of CRC cells were restrained by circXPO1 depletion or WWC2 overexpression.

CONCLUSIONS

m6A-modified circXPO1 by ALKBH5/IGF2BP2 axis destabilized WWC2 via interaction with FMRP to activate Hippo-YAP pathway, thereby facilitating CRC growth and metastasis. Targeting circXPO1 might be a potential therapeutic strategy for CRC.

Unraveling the Regulatory Role of HuR/microRNA Axis in Colorectal Cancer Tumorigenesis

Colorectal cancer (CRC) remains a significant global health burden with high incidence and mortality. MicroRNAs (miRNAs) are small non-protein coding transcripts, conserved throughout evolution, with an important role in CRC tumorigenesis, and are either upregulated or downregulated in various cancers. RNA-binding proteins (RBPs) are known as essential regulators of miRNA activity. Human antigen R (HuR) is a prominent RBP known to drive tumorigenesis with a pivotal role in CRC. In this review, we discuss the regulatory role of the HuR/miRNA axis in CRC. Interestingly, miRNAs can directly target HuR, altering its expression and activity. However, HuR can also stabilize or degrade miRNAs, forming complex feedback loops that either activate or block CRC-associated signaling pathways. Dysregulation of the HuR/miRNA axis contributes to CRC initiation and progression. Additionally, HuR-miRNA regulation by other small non-coding RNAs, circular RNA (circRNAs), or long-non-coding RNAs (lncRNAs) is also explored here. Understanding this HuR-miRNA interplay could reveal novel biomarkers with better diagnostic or prognostic accuracy.

Fatty acid metabolism-related enzymes in colorectal cancer metastasis: from biological function to molecular mechanism

Colorectal cancer (CRC) is a highly aggressive and life-threatening malignancy that metastasizes in ~50% of patients, posing significant challenges to patient survival and treatment. Fatty acid (FA) metabolism regulates proliferation, immune escape, metastasis, angiogenesis, and drug resistance in CRC. FA metabolism consists of three pathways: de novo synthesis, uptake, and FA oxidation (FAO). FA metabolism-related enzymes promote CRC metastasis by regulating reactive oxygen species (ROS), matrix metalloproteinases (MMPs), angiogenesis and epithelial-mesenchymal transformation (EMT). Mechanistically, the PI3K/AKT/mTOR pathway, wnt/β-catenin pathway, and non-coding RNA signaling pathway are regulated by crosstalk of enzymes related to FA metabolism. Given the important role of FA metabolism in CRC metastasis, targeting FA metabolism-related enzymes and their signaling pathways is a potential strategy to treat CRC metastasis.

Novel Peptide DR3penA as a Low-Toxicity Antirenal Fibrosis Agent by Suppressing the TGF-β1/miR-212-5p/Low-Density Lipoprotein Receptor Class a Domain Containing 4/Smad Axis

Renal fibrosis is a complex pathological process that contributes to the development of chronic kidney disease due to various risk factors. Conservative treatment to curb progression without dialysis or renal transplantation is widely applicable, but its effectiveness is limited. Here, the inhibitory effect of the novel peptide DR3penA (DHα-(4-pentenyl)-AlaNPQIR-NH2), which was developed by our group, on renal fibrosis was assessed in cells and mice with established fibrosis and fibrosis triggered by transforming growth factor-β1 (TGF-β1), unilateral ureteral obstruction, and repeated low-dose cisplatin. DR3penA preserved renal function and ameliorated renal fibrosis at a dose approximately 100 times lower than that of captopril, which is currently used in the clinic. DR3penA also significantly reduced existing fibrosis and showed similar efficacy after subcutaneous or intraperitoneal injection. Mechanistically, DR3penA repressed TGF-β1 signaling via miR-212-5p targeting of low-density lipoprotein receptor class a domain containing 4, which interacts with Smad2/3. In addition to having good pharmacological effects, DR3penA could preferentially target injured kidneys and exhibited low toxicity in acute and chronic toxicity experiments. These results unveil the advantages of DR3penA regarding efficacy and toxicity, making it a potential candidate compound for renal fibrosis therapy.