Genetically encoded photoswitches have enabled spatial and temporal control of cellular events to achieve tailored functions in living cells, but their applications to probe the structure-function relations of signaling proteins are still underexplored. We illustrate herein the incorporation of various blue light-responsive photoreceptors into modular domains of the stromal interaction molecule 1 (STIM1) to manipulate protein activity and faithfully recapitulate STIM1-mediated signaling events. Capitalizing on these optogenetic tools, we identify the molecular determinants required to mediate protein oligomerization, intramolecular conformational switch, and protein-target interactions. In parallel, we have applied these synthetic devices to enable light-inducible gating of calcium channels, conformational switch, dynamic protein-microtubule interactions and assembly of membrane contact sites in a reversible manner. Our optogenetic engineering approach can be broadly applied to aid the mechanistic dissection of cell signaling, as well as non-invasive interrogation of physiological processes with high precision.

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The p16(INK4a) gene is a cell cycle inhibitor and a major tumour suppressor protein, but the regulation and effects on tumour cells' invasion process of p16(INK4a) is poorly known. A role for p16(INK4a) in basal cell carcinoma is suggested by the observation that p16(INK4a) was upregulated at the invasive front of the majority of basal cell carcinomas with infiltrative growth patterns, accompanied by cessation of proliferation. In this paper, we explore whether there is a difference of tumour cells' proliferative activity between the centre and the invasion front tissues of human colorectal cancer and its relationship with the expression and methylation status of p16(INK4a) gene. We obtained the centre and the invasion front tissues of colorectal cancer respectively by the technology of laser mircodissection. The expressions of the proliferating cell nuclear antigen ki67 and p16(INK4a) were assessed by immunohistochemistry, methylation-specific polymerase chain reaction (MS-PCR) and reverse-transcription polymerase chain reaction (RT-PCR) in the different areas. There was a significant difference in the expressions of ki67 between the centre and the invasion front tissues (p < 0.05). The difference did not correlate with age, sex, Dukes stage but did correlate with expression of p16(INK4a) gene (chi(2) = 25.37, p < 0.01). Furthermore, hypermethylation of the promoter was the major mechanism of inactivation of p16(INK4a) in the centre areas. Demethylation of the p16(INK4a) promoter, the elevated expression of p16(INK4a) protein and mRNA level was proved in the invasion front. Our finding suggested that enhanced invasion in tumours was accompanied by ceased proliferation in the invasion fronts of human colorectal cancer. This interesting phenomenon may be due to not only the microenvironment, but also the molecular changes such as p16(INK4a) status.

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Marine-derived chitooligosaccharides (CHOS) are a new class of anti-inflammatory natural products characterized by its nontoxity, low-cost and small-molecule. But whether CHOS exert a protective action against inflammatory bowel diseases (IBDs) is not yet fully understood. This paper studied the effect of CHOS on the inflammation and apoptosis of intestinal epithelial cells (IECs) using lipopolysaccharides (LPS)-stimulated Caco-2 cells as an in vitro model of IBD. Caco-2 cells were pre-incubated with various concentrations of CHOS (0.25, 0.5 and 1.0 mg/ml) for 2 h prior to being co-stimulated or not with LPS at a concentration of 1µg/mL for 48h. Cell apoptosis was measured with Annexin V-FITC and propidium iodide (PI) assay by flow cytometry. The levels of proinflammatory mediators including tumor necrosis factor (TNF)-α, interleukin-8 and prostaglandin (PG) E2 were analyzed using Enzyme-linked Immunosorbent Assay. And the cell expression of toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), caspase-3, bcl-2, and cyclooxygenase (COX)-2 was examined by western blot. We observed that CHOS significantly and concentration-dependently inhibited the LPS-induced inflammatory response and apoptosis of IECs, which was evidenced by the reduction in the release of proinflammatory mediators TNF-α, PGE2, the expression of COX-2, apoptotic (Annexin V + /PI -) cell populations, the pro-apoptotic caspase-3 expression, and the enhancement of the expression level of anti-apoptotic bcl-2. And CHOS treatment significantly reduced the protein expressions of TLR4 and NF-κB in LPS-stimulated Caco-2 cells. Thus, the present study suggests the potential medical use of CHOS in the control of IBDs, which may be due to the downregulation of TLR4/NF-κB pathway.

Ulcerative colitis (UC) is a chronic inflammatory bowel disease involving mainly the colorectal mucosa and submucosa, the incidence of which has been on the rise in recent years. Nuclear factor erythroid 2-related factor 2 (Nrf2), known for its key function as a transcription factor, is pivotal in inducing antioxidant stress and regulating inflammatory responses. Numerous investigations have demonstrated the involvement of the Nrf2 pathway in maintaining the development and normal function of the intestine, the development of UC, and UC-related intestinal fibrosis and carcinogenesis; meanwhile, therapeutic agents targeting the Nrf2 pathway have been widely investigated. This paper reviews the research progress of the Nrf2 signaling pathway in UC.

Gastric cancer is the fourth commonest cancer in the world and the second leading cause of cancer-related death. Investigation of gastric cancer metastasis is one of the hottest and major focuses in cancer research. Growing evidence manifested that primo vascular system (PVS) is a new kind of circulatory system beyond vascular and lymphatic system. Previous researches revealed that PVS is a specific tissue between endothelium and mesenchyme and is involved in cancer, especially in tumor metastasis and regeneration. In current study, we investigated the role of primo vessels in gastric cancer metastasis and its possible relationship to vascular vessels formation. Our results indicated that primo vessels were involved in gastric cancer metastasis. We observed blood vessel-mediated metastasis, primo vessel-mediated metastasis, and an intermediate state between them. We deduced that primo vessels may be precursors of blood vessels. These results possibly provided a thoroughly new theoretic development in cancer metastasis.

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