Colorectal cancer (CRC) is the third most common cancer and has a high metastasis and reoccurrence rate. Long noncoding RNAs (lncRNAs) play an important role in CRC growth and metastasis. Recent studies revealed that lncRNAs participate in CRC progression by coordinating with microRNAs (miRNAs) and protein-coding mRNAs. LncRNAs function as competitive endogenous RNAs (ceRNAs) by competitively occupying the shared binding sequences of miRNAs, thus sequestering the miRNAs and changing the expression of their downstream target genes. Such ceRNA networks formed by lncRNA/miRNA/mRNA interactions have been found in a broad spectrum of biological processes in CRC, including liver metastasis, epithelial to mesenchymal transition (EMT), inflammation formation, and chemo-/radioresistance. In this review, we summarize typical paradigms of lncRNA-associated ceRNA networks, which are involved in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the competitive crosstalk among RNA transcripts and the novel targets for CRC prognosis and therapy.

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide and CRC therapy remains unsatisfactory. In recent decades, nitric oxide (NO)—a free-radical gas—plus its endogenous producer NO synthases (NOS), have attracted considerable attention. NO exerts dual effects (pro- and anti-tumor) in cancers. Endogenous levels of NO promote colon neoplasms, whereas exogenously sustained doses lead to cytotoxic functions. Importantly, NO has been implicated as an essential mediator in many signaling pathways in CRC, such as the Wnt/β-catenin and extracellular-signal-regulated kinase (ERK) pathways, which are closely associated with cancer initiation, metastasis, inflammation, and chemo-/radio-resistance. Therefore, NO/NOS have been proposed as promising targets in the regulation of CRC carcinogenesis. Clinically relevant NO-donating agents have been developed for CRC therapy to deliver a high level of NO to tumor sites. Notably, inducible NOS (iNOS) is ubiquitously over-expressed in inflammatory-associated colon cancer. The development of iNOS inhibitors contributes to targeted therapies for CRC with clinical benefits. In this review, we summarize the multifaceted mechanisms of NO-mediated networks in several hallmarks of CRC. We review the clinical manifestation and limitations of NO donors and NOS inhibitors in clinical trials. We also discuss the possible directions of NO/NOS therapies in the immediate future.

The accurate assessment of drug concentrations in biodistribution studies is crucial for evaluating the efficacy and toxicity of compounds in drug development. As the concentration of biologics in plasma can be higher than in tissue due to their potentially low volume of distribution, transcardiac perfusion is commonly employed to reduce the influence of excess drugs in residual blood. However, there is a lack of consistency in the literature on the conditions and methods of perfusion. To enhance blood removal during transcardiac perfusion, sodium nitrite (NaNO₂), a vasodilator, has been widely used with concentrations up to 5% in publications. However, we found that such high NaNO₂ could disrupt the BBB during perfusion, which should be avoided in experiments. In this study, we examined the impact of various vasodilators on blood–brain barrier integrity and vascular permeability using the ratio of FITC-Dextran to Texas Red-Dextran (FITC/Texas Red). Additionally, we optimized perfusion conditions—including euthanasia method and perfusion flow rate—based on hemoglobin levels and the FITC/Texas Red ratio in tissues. Despite the superiority of NaNO₂ in terms of solubility and cost over other vasodilators, we found that 2% NaNO₂ disrupted blood–brain barrier integrity, significantly altering the FITC/Texas Red ratio. In contrast, 100 mM NaNO₂ did not significantly affect this ratio. Moreover, under Ketamine/Xylazine (Ket/Xyl) anesthesia, which reduced blood clot formation compared to CO₂ euthanasia, 100 mM NaNO₂ achieved the lowest hemoglobin levels in the brain. Compared to other vasodilators and the PBS control group, 100 mM NaNO₂ decreased the tissue/plasma ratio (K_p,t) but not brain/plasma ratio (K_p,b) of hIgG1 and human transferrin. We have developed a method to efficiently evaluate blood–brain barrier integrity during transcardiac perfusion. The combination of Ket/Xyl anesthesia and 100 mM NaNO₂ effectively removes residual blood from tissues without significantly affecting blood vessel permeability.