Colorectal cancer (CRC) is one of the most prevalent cancers due to its frequency and high rate of mortality. Polyamine-vectorized anticancer drugs possess multiple biological properties. Of these drugs, 9F has been shown to inhibit tumor growth and the metastasis of hepatocellular carcinoma. This current study aims to investigate the effects of 9F on CRC and determine its molecular mechanisms of action. Our findings demonstrate that 9F inhibits CRC cell growth by inducing apoptosis and cell cycle arrest, and suppresses migration, invasion and angiogenesis in vitro, resulting in the inhibition of tumor growth and metastasis in vivo. Based on RNA-seq data, further bioinformatic analyses suggest that 9F exerts its anticancer activities through p53 signaling, which is responsible for the altered expression of key regulators of the cell cycle, apoptosis, the epithelial-to-mesenchymal transition (EMT), and angiogenesis. In addition, 9F is more effective than amonafide against CRC. These results show that 9F can be considered as a potential strategy for CRC treatment.

Increasing the level of reactive oxygen species (ROS) in cancer cells has been suggested as a viable approach to cancer therapy. Our previous study has demonstrated that mitochondria-targeted flavone-naphthalimide-polyamine conjugate 6c elevates the level of ROS in cancer cells. However, the detailed role of ROS in 6c-treated cancer cells is not clearly stated. The biological effects and in-depth mechanisms of 6c in cancer cells need to be further investigated. In this study, we confirmed that mitochondria are the main source of 6c-induced ROS, as demonstrated by an increase in 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) and MitoSox fluorescence. Compound 6c-induced mitochondrial ROS caused mitochondrial dysfunction and lysosomal destabilization confirmed by absolute quantitation (iTRAQ)-based comparative proteomics. Compound 6c-induced metabolic pathway dysfunction and lysosomal destabilization was attenuated by N-acetyl-L-cysteine (NAC). iTRAQ-based comparative proteomics showed that ROS regulated the expression of 6c-mediated proteins, and treatment with 6c promoted the formation of autophagosomes depending on ROS. Compound 6c-induced DNA damage was characterized by comet assay, p53 phosphorylation, and γH2A.X, which was diminished by pretreatment with NAC. Compound 6c-induced cell death was partially reversed by 3-methyladenine (3-MA), bafilomycin (BAF) A1, and NAC, respectively. Taken together, the data obtained in our study highlighted the involvement of mitochondrial ROS in 6c-induced autophagic cell death, mitochondrial and lysosomal dysfunction, and DNA damage.

The yft1 tomato mutant has a yellow-fruited phenotype controlled by a recessive gene ( YFT1 ), which has been shown by map-based cloning to be a homolog of ETHYLENE INSENSITIVE 2 ( EIN2 ). The genetic lesion of the YFT1 allele of yft1 is attributed to a 573 bp DNA fragment (IF ₅₇₃ ) insertion at 1,200 bp downstream of the transcription start site (TSS). Transcriptome analysis revealed that the mutation resulted in 5,053 differentially expressed genes (DEGs) in the fruit pericarp compared with the M82 wild type cultivar. These were annotated as being involved in ethylene synthesis, chromoplast development, and carotenoid synthesis. Genetic lesion in YFT1 caused a reduction in its own transcript levels in yft1 and impaired ethylene emission and signal transduction, delayed chromoplast development and decreased carotenoid accumulation. The molecular mechanism underlying the reduced expression of YFT1 in yft1 was examined at both the RNA and DNA levels. The IF ₅₇₃ event was shown to introduce two negative regulatory sequences located at -272 to -173 bp and -172 to -73 bp in the YFT1 allele promoter, causing alterative splicing due to aberrant splicing sites, and also altering the structure of the open reading frame in the 5’-UTR. This study contributes to the understanding of color formation in tomato fruit. One-sentence summary: Lesion happened in regulatory region impairs expression of a key gene of ethylene signal pathway, and alters fruit color in tomato due to effect of carotenoids accumulation and ethylene synthesis.