αE‐catenin is a candidate tumor suppressor for the development of E‐cadherin‐expressing lobular‐type breast cancer

Although mutational inactivation of E‐cadherin (CDH1) is the main driver of invasive lobular breast cancer (ILC), approximately 10–15% of all ILCs retain membrane‐localized E‐cadherin despite the presence of an apparent non‐cohesive and invasive lobular growth pattern. Given that ILC is dependent on constitutive actomyosin contraction for tumor development and progression, we used a combination of cell systems and in vivo experiments to investigate the consequences of α‐catenin (CTNNA1) loss in the regulation of anchorage independence of non‐invasive breast carcinoma. We found that inactivating somatic CTNNA1 mutations in human breast cancer correlated with lobular and mixed ducto‐lobular phenotypes. Further, inducible loss of α‐catenin in mouse and human E‐cadherin‐expressing breast cancer cells led to atypical localization of E‐cadherin, a rounded cell morphology, and anoikis resistance. Pharmacological inhibition experiments subsequently revealed that, similar to E‐cadherin‐mutant ILC, anoikis resistance induced by α‐catenin loss was dependent on Rho/Rock‐dependent actomyosin contractility. Finally, using a transplantation‐based conditional mouse model, we demonstrate that inducible inactivation of α‐catenin instigates acquisition of lobular features and invasive behavior. We therefore suggest that α‐catenin represents a bona fide tumor suppressor for the development of lobular‐type breast cancer and as such provides an alternative event to E‐cadherin inactivation, adherens junction (AJ) dysfunction, and subsequent constitutive actomyosin contraction. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.     

(-)-Epigallocatechin-3-gallate inhibition of ultraviolet B-induced AP-1 activity

Green tea polyphenols have been shown to inhibit cancer in a variety of tumor models, including ultraviolet B (UVB)-induced non-melanoma skin cancer. In green tea extracts, the major dry mass constituent is the family of catechins, of which (-)-epigallocatechin-(3)-gallate (EGCG) is considered to be important for the chemopreventive activity. EGCG has been shown to have antioxidant properties, but there has been little progress toward identifying the specific targets and mechanisms of its action. Using cultured human keratinocytes, we show that UVB- induced AP-1 activity is inhibited by EGCG in a dose range of 5.45 nM to 54.5 microM. EGCG is effective at inhibiting AP-1 activity when applied before, after or both before and after UVB irradiation. EGCG also inhibits AP-1 activity in the epidermis of a transgenic mouse model. This work begins to define a mechanism by which EGCG could be acting to inhibit UVB-induced tumor formation.      

参三七皂甙Rg1对实验性血栓形成的影响及其机制探讨

用大鼠动静脉血栓形成模型，研究参三七皂甙Ｒｇ１抗血栓作用。结果表明，参三七皂甙Ｒｇ１可明显降低实验性血栓形成，对大鼠血浆纤溶系统亦有明显作用，可升高血浆中组织纤溶酶原激活物（ｔＰＡ）活性和活性型ｔＰＡ百分比，降低组织纤溶酶原激活物抑制剂（ＰＡＩ）活性。同时利用培养大鼠血管内皮细胞实验，发现Ｒｇ１可以剂量依赖性提高血管内皮细胞一氧化氮（ＮＯ）释放。提示Ｒｇ１抗血栓作用与增强纤溶系统活性，促进血管内皮ＮＯ释放有关     

Continuous detection of extracellular ATP on living cells by using atomic force microscopy.

Atomic force microscopy is a powerful technique used to investigate the surface of living cells under physiological conditions. The resolution of the instrument is mainly limited by the softness of living cells and the interactions with the scanning tip (cantilever). Atomic force microscopy, in combination with myosin-functionalized cantilevers, was used in the detection of ATP concentrations in solution and on living cells. Functionally active tips were used to scan the surface of cells in culture and to show that the CFTR+ cell line (S9) had a basal surface ATP concentration that could be detected with atomic force microscopy (n = 10). ATP-dependent signals were not detectable in cells scanned with noncoated or heat-inactivated enzyme-coated tips (n = 9). Enzymatically active tips may serve as a model for future development of atomic force microscopy biosensors that can simultaneously detect topographical and biologically important compounds at the surface microenvironment of living cells.     

A phase I trial of intranasal Moli1901 for cystic fibrosis

BACKGROUND: The peptide drug Moli1901 activates an alternative chloride channel that is present in cystic fibrosis (CF) nasal and airway epithelia. Doing so bypasses the dysfunctional CF transmembrane regulator. STUDY OBJECTIVE: To determine whether intranasal Moli1901 is safe, tolerable, and will induce chloride transport in healthy volunteers and CF subjects. DESIGN: A single-blind (to the participant), randomized, placebo-controlled, dose-escalation study of intranasal Moli1901 was performed in four healthy non-CF participants and four participants with CF. Drug or placebo was administered by intranasal superfusion, and nasal potential difference responses were continuously monitored during sequential dose escalations at 1-min intervals from 0.01 through 10 micro mol/L. RESULTS: Neither Moli1901 nor placebo were associated with visible changes such as edema, erythema, drainage, secretions, or ulcer formation. No elevations in lactate dehydrogenase, albumin, or cell counts were observed in nasal lavage fluid after administration. No clinically significant changes in FEV(1) or other toxicity parameters occurred. Changes in the nasal potential difference (NPD) induced by chloride-free, amiloride-containing Ringers solution and by subsequent superfusion with the same solution plus 10 micro mol/L isoproterenol were consistent with both an acute and a sustained change in chloride transport in response to Moli1901. A similar analysis of NPD in the four CF participants demonstrated an acute response that resolved more quickly. A dose-response relationship to Moli1901 was observed in non-CF participants, but a greater range of variability within the CF participants contributed to the lack of a clear dose-response relationship in this group. CONCLUSION: Moli1901 stimulates chloride transport in normal and CF nasal epithelia in vivo, but may have a shorter duration of action in CF participants.     

Gout-causing Q141K mutation in ABCG2 leads to instability of the nucleotide-binding domain and can be corrected with small molecules

The multidrug ATP-binding cassette, subfamily G, 2 (ABCG2) transporter was recently identified as an important human urate transporter, and a common mutation, a Gln to Lys substitution at position 141 (Q141K), was shown to cause hyperuricemia and gout. The nature of the Q141K defect, however, remains undefined. Here we explore the Q141K ABCG2 mutation using a comparative approach, contrasting it with another disease-causing mutation in an ABC transporter, the deletion of Phe-508 (ΔF508) in the cystic fibrosis transmembrane conductance regulator (CFTR). We found, much like in ΔF508 CFTR, that the Q141K mutation leads to instability in the nucleotide-binding domain (NBD), a defect that translates to significantly decreased protein expression. However, unlike the CFTR mutant, the Q141K mutation does not interfere with the nucleotide-binding domain/intracellular loop interactions. This investigation has also led to the identification of critical residues involved in the protein–protein interactions necessary for the dimerization of ABCG2: Lys-473 (K473) and Phe-142 (F142). Finally, we have demonstrated the utility of using small molecules to correct the Q141K defect in expression and function as a possible therapeutic approach for hyperuricemia and gout.