Taurine (Tau) has been shown to possess cancer therapeutic effect through induction of apoptosis, while the underlying molecular mechanism of its anti-cancer effect is not well understood. PUMA (p53-upregulated modulator of apoptosis) plays an important role in the process of apoptosis induction in a variety of human tumor cells in both p53-dependent and -independent manners. However, whether PUMA is involved in the process of Tau-induced apoptosis in cancer cells has not been well studied. In the present study, we treated human colorectal cancer cells HT-29 (mutant p53) and LoVo (wild-type p53) with different concentrations of Tau, which led to the repression of cell proliferation and induction of apoptosis in both cell lines. Meanwhile, we also observed the increased expression of PUMA and high Bax/Bcl-2 ratios. To determine the role of PUMA in Tau-induced apoptosis, we used small interfering RNA interference to suppress PUMA expression. As a result, apoptosis was decreased in response to Tau treatment. All these results indicated that PUMA plays a critical role in Tauinduced apoptosis pathway in human colorectal cancer cells. Demonstration of the molecular mechanism involved in the anti-tumor effect of Tau may be useful in the therapeutic target selection for p53-deficient colorectal cancer.

Primary liver cancer is one of the leading causes for cancer-related death worldwide. Transforming growth factor beta (TGF-β) is a pleiotropic cytokine that signals through membrane receptors and intracellular Smad proteins, which enter the nucleus upon receptor activation and act as transcription factors. TGF-β inhibits liver tumorigenesis in the early stage by inducing cytostasis and apoptosis, but promotes malignant progression in more advanced stages by enhancing cancer cell survival, EMT, migration, invasion and finally metastasis. Understanding the molecular mechanisms underpinning the multi-faceted roles of TGF-β in liver cancer has become a persistent pursuit during the last two decades. Contextual regulation fine-tunes the robustness, duration and plasticity of TGF-β signaling, yielding versatile albeit specific responses. This involves multiple feedback and feed-forward regulatory loops and also the interplay between Smad signaling and non-Smad pathways. This review summarizes the known regulatory mechanisms of TGF-β signaling in liver cancer, and how they channel, skew and even switch the actions of TGF-β during cancer progression.

To investigate the effects of taurine on cell proliferation and apoptosis, the human lung cancer A549 cell line and xenograft tumors in nude mice were used. The effects of taurine on cell proliferation and apoptosis were observed at time points of 24, 48 and 72 h after treatment using an MTT assay to detect the survival rate, and flow cytometry to detect the apoptotic rate. Western blot analysis was performed to examine the levels of p53 upregulated modulator of apoptosis (PUMA), BCL2, apoptosis regulator (Bcl-2) and BCL2-associated X, apoptosis regulator (Bax) in A549 cells. The level of PUMA, Bax and Bcl-2 proteins in the mouse xenograft tumors treated with taurine and/or exogenous PUMA were assessed by immunohistochemistry, with taurine suppressing the proliferation of the human lung cancer A549 cell line in a concentration-dependent manner, and it significantly enhanced the apoptosis rate at all concentrations. Taurine induced the significant upregulation of PUMA and Bax, but led to downregulation of Bcl-2. In comparison to the control group, taurine treatment markedly reduced the volume and weight of A549-derived xenograft tumors in nude mice. Expression of PUMA and Bax were upregulated in the xenograft tumors following taurine treatment, whereas Bcl-2 was downregulated. In addition, the inhibitory effect of taurine and exogenous PUMA on tumor growth was significantly higher than that of a single treatment of taurine or exogenous PUMA. It can therefore be concluded that taurine can inhibit cell proliferation of the human lung cancer A549 cell line and the growth of the xenograft tumors, whereas PUMA serves an important role in taurine-induced growth suppression.

CXXC5 is a member of the CXXC‐type zinc‐finger protein family. Proteins in this family play a pivotal role in epigenetic regulation by binding to unmethylated CpG islands in gene promoters through their characteristic CXXC domain. CXXC5 is a short protein (322 amino acids in length) that does not have any catalytic domain, but is able to bind to DNA and act as a transcription factor and epigenetic factor through protein‐protein interactions. Intriguingly, increasing evidence indicates that expression of the CXXC5 gene is controlled by multiple signaling pathways and a variety of transcription factors, positioning CXXC5 as an important signal integrator. In addition, CXXC5 is capable of regulating various signal transduction processes, including the TGF‐β, Wnt and ATM‐p53 pathways, thereby acting as a novel and crucial signaling coordinator. CXXC5 plays an important role in embryonic development and adult tissue homeostasis by regulating cell proliferation, differentiation and apoptosis. In keeping with these functions, aberrant expression or altered activity of CXXC5 has been shown to be involved in several human diseases including tumourigenesis. This review summarizes the current understanding of CXXC5 as a transcription factor and signaling regulator and coordinator.

The rapid development and popularization of smart phones and mobile internet has created a new social lifestyle, and correspondingly prompts the transformation of network teaching from desktop computer to mobile teaching. This article has compared the pros and cons of Tsinghua Education Online and WeChat official account (WOA) in fulfilling teaching functions. We also described the construction of WOA platform with the example of WOA‐based teaching in biochemistry and molecular biology. The platform can establish nearly 75 menu catalogs and 2,250 items, which is capable for the publication of any types of teaching materials and information. The WOA teaching is well accepted and becomes popular in China due to the free, interactive, attractive, adaptable, portable, sustainable, and more participatory teaching styles. © 2018 International Union of Biochemistry and Molecular Biology, 46(5):555–560, 2018.