Anti-angiogenesis is an important and promising strategy in cancer therapy. However, the current methods using anti-vascular endothelial growth factor A (VEGFA) antibodies or inhibitors targeting VEGFA receptors are not as efficient as expected partly due to their low efficiencies in blocking VEGFA signaling in vivo. Until now, there is still no method to effectively block VEGFA production in cancer cells from the very beginning, i.e., from the transcriptional level. Here, we aimed to find bioactive small molecules to block VEGFA transcription.

Cervical cancer is the leading cause of death among women with cancer worldwide. Here, we performed an integrative analysis of Illumina HumanMethylation450K and RNA-seq data from TCGA to identify cervical cancer-specific DNA methylation markers. We first identified differentially methylated and expressed genes and examined the correlation between DNA methylation and gene expression. The DNA methylation profiles of 12 types of cancers, including cervical cancer, were used to generate a candidate set, and machine-learning techniques were adopted to define the final cervical cancer-specific markers in the candidate set. Then, we assessed the protein levels of marker genes by immunohistochemistry by using tissue arrays containing 93 human cervical squamous cell carcinoma samples and cancer-adjacent normal tissues. Promoter methylation was negatively correlated with the local regulation of gene expression. In the distant regulation of gene expression, the methylation of hypermethylated genes was more likely to be negatively correlated with gene expression, while the methylation of hypomethylated genes was more likely to be positively correlated with gene expression. Moreover, we identified four cervical cancer-specific methylation markers, cg07211381 (RAB3C), cg12205729 (GABRA2), cg20708961 (ZNF257), and cg26490054 (SLC5A8), with 96.2% sensitivity and 95.2% specificity by using the tenfold cross-validation of TCGA data. The four markers could distinguish tumors from normal tissues with a 94.2, 100, 100, and 100% AUC in four independent validation sets from the GEO database. Overall, our study demonstrates the potential use of methylation markers in cervical cancer diagnosis and may boost the development of new epigenetic therapies.

Metabolic reprogramming to fulfill the biosynthetic and bioenergetic demands of cancer cells has aroused great interest in recent years. However, metabolic reprogramming for cancer metastasis has not been well elucidated. Here, we screened a subpopulation of breast cancer cells with highly metastatic capacity to the lung in mice and investigated the metabolic alternations by analyzing the metabolome and the transcriptome, which were confirmed in breast cancer cells, mouse models, and patients’ tissues. The effects and the mechanisms of nucleotide de novo synthesis in cancer metastasis were further evaluated in vitro and in vivo. In our study, we report an increased nucleotide de novo synthesis as a key metabolic hallmark in metastatic breast cancer cells and revealed that enforced nucleotide de novo synthesis was enough to drive the metastasis of breast cancer cells. An increased key metabolite of de novo synthesis, guanosine-5'-triphosphate (GTP), is able to generate more cyclic guanosine monophosphate (cGMP) to activate cGMP-dependent protein kinases PKG and downstream MAPK pathway, resulting in the increased tumor cell stemness and metastasis. Blocking de novo synthesis by silencing phosphoribosylpyrophosphate synthetase 2 (PRPS2) can effectively decrease the stemness of breast cancer cells and reduce the lung metastasis. More interestingly, in breast cancer patients, the level of plasma uric acid (UA), a downstream metabolite of purine, is tightly correlated with patient’s survival. Our study uncovered that increased de novo synthesis is a metabolic hallmark of metastatic breast cancer cells and its metabolites can regulate the signaling pathway to promote the stemness and metastasis of breast cancer.

New domains were progressively added to cytoplasmic aminoacyl transfer RNA (tRNA) synthetases during evolution. One example is the UNE-S domain, appended to seryl-tRNA synthetase (SerRS) in species that developed closed circulatory systems. Here we show using solution and crystal structure analyses and in vitro and in vivo functional studies that UNE-S harbours a robust nuclear localization signal (NLS) directing SerRS to the nucleus where it attenuates vascular endothelial growth factor A expression. We also show that SerRS mutants previously linked to vasculature abnormalities either deleted the NLS or have the NLS sequestered in an alternative conformation. A structure-based second-site mutation, designed to release the sequestered NLS, restored normal vasculature. Thus, the essential function of SerRS in vascular development depends on UNE-S. These results are the first to show an essential role for a tRNA synthetase-associated appended domain at the organism level, and suggest that acquisition of UNE-S has a role in the establishment of the closed circulatory systems of vertebrates.

Recent studies suggested an essential role for seryl-tRNA synthetase (SerRS) in vascular development. This role is specific to SerRS among all tRNA synthetases and is independent of its well-known aminoacylation function in protein synthesis. A unique nucleus-directing domain, added at the invertebrate-to-vertebrate transition, confers this novel non-translational activity of SerRS. Previous studies showed that SerRS, in some unknown way, controls VEGFA expression to prevent vascular over-expansion. Using in vitro, cell and animal experiments, we show here that SerRS intervenes by antagonizing c-Myc, the major transcription factor promoting VEGFA expression, through a tandem mechanism. First, by direct head-to-head competition, nuclear-localized SerRS blocks c-Myc from binding to the VEGFA promoter. Second, DNA-bound SerRS recruits the SIRT2 histone deacetylase to erase prior c-Myc-promoted histone acetylation. Thus, vertebrate SerRS and c-Myc is a pair of ‘Yin-Yang’ transcriptional regulator for proper development of a functional vasculature. Our results also discover an anti-angiogenic activity for SIRT2.

TGF-β-induced factor homeobox 2 (TGIF2) is a transcription regulator that plays essential roles in the regulation of development and cell fate decisions. Aberrant expression of TGIF family proteins has been observed in several cancers, including ovarian, esophageal, and colorectal cancers. Here, we report that TGIF2 mediates the EGFR–RAS–ERK signaling pathway to enhance the stemness of lung adenocarcinoma (LUAD) cells and, therefore, promote the progression and metastasis of LUAD. We found that high TGIF2 expression was closely correlated with tumor growth, lymph node metastasis, and survival of patients with LUAD. Mice bearing TGIF2-silenced H1299 xenografts developed smaller tumors and fewer lung metastases. Importantly, silencing TGIF2 decreased the cancer stem cell (CSC)-like properties in A549 and H1299 cells. Furthermore, we identified that TGIF2 binding to the OCT4 promoter promotes its expression. In both LUAD cells and in vivo LUAD mouse models, we revealed that EGFR–RAS–ERK signaling phosphorylated TGIF2 and increased its stability, which was important for TGIF2-promoted LUAD stemness since phosphorylation-deficient TGIF2 mutants lost these functions. Thus, our study revealed that an important factor, TGIF2, bridges EGFR signaling to the CSC characteristics of LUAD cells, which can be utilized as an effective target for LUAD therapy.