Identification of a small molecule 1,4-bis-[4-(3-phenoxy-propoxy)-but-2-ynyl]-piperazine as a novel inhibitor of the transcription factor p53

Prevalent Accumulation of Non-Optimal Codons through Somatic Mutations in Human Cancers

Cancer is characterized by uncontrolled cell growth, and the cause of different cancers is generally attributed to checkpoint dysregulation of cell proliferation and apoptosis. Recent studies have shown that non-optimal codons were preferentially adopted by genes to generate cell cycle-dependent oscillations in protein levels. This raises the intriguing question of how dynamic changes of codon usage modulate the cancer genome to cope with a non-controlled proliferative cell cycle. In this study, we comprehensively analyzed the somatic mutations of codons in human cancers, and found that non-optimal codons tended to be accumulated through both synonymous and non-synonymous mutations compared with other types of genomic substitution. We further demonstrated that non-optimal codons were prevalently accumulated across different types of cancers, amino acids, and chromosomes, and genes with accumulation of non-optimal codons tended to be involved in protein interaction/signaling networks and encoded important enzymes in metabolic networks that played roles in cancer-related pathways. This study provides insights into the dynamics of codons in the cancer genome and demonstrates that accumulation of non-optimal codons may be an adaptive strategy for cancerous cells to win the competition with normal cells. This deeper interpretation of the patterns and the functional characterization of somatic mutations of codons will help to broaden the current understanding of the molecular basis of cancers.

Effects of TNF-α on Cementoblast Differentiation, Mineralization, and Apoptosis

Tumor necrosis factor–α (TNF-α) is involved in various inflammatory processes, including periodontitis. Although the influences of TNF-α on periodontal ligament fibroblasts and osteoblasts have been widely documented, its effects on cementoblasts, the cells responsible for cementum production, remain largely unknown. In this study, we found that TNF-α suppressed the mineralization ability of cementoblasts by inhibiting differentiation and inducing apoptosis. Various signaling pathways, such as p53, PP2AC, p38, Erk1/2, JNK, PI3K-Akt, and NF-κB, were activated during this process. The use of a specific inhibitor and siRNA transfection confirmed that the effects of TNF-α on differentiation and apoptosis in cementoblasts were partially abrogated by inhibiting p53 activity. By contrast, the effects of TNF-α were even exacerbated by the inhibition of the p38, Erk1/2, JNK, PI3K-Akt, and NF-κB pathways. Moreover, p53 activity was further enhanced by blocking the p38, Erk1/2, JNK, and PI3K-Akt signaling pathways. Taken together, these results suggested that the differentiation inhibition and apoptosis in cementoblasts induced by TNF-α were partially dependent on p53 activity. The p38, Erk1/2, JNK, PI3K-Akt, and NF-κB pathways were also activated but acted as balancing players to limit rather than conduct the negative effects of TNF-α. These balancing effects were dependent, or at least partially dependent, on p53, except for the NF-κB pathway.