Thapsigargin, Inhibitor of Sarco-Endoplasmic Ca2+-ATPase, Effectively Suppresses the Expression of S100A4 Protein in Human Breast Cancer Cell Line

Calcicoptosis induced by purple sweet potato anthocyanins through the nonosmotic regulation of the NFAT5/S100A4-S100A9 pathway in acute lymphoblastic leukemia

Purple sweet potato is considered an abundant, inexpensive, and ideal source of anthocyanins. Purple sweet potato anthocyanins (PSPAs) have been shown to possess high antimutagenicity and antitumor effects due to the abundance of acylated anthocyanins. However, the effect and underlying mechanism of PSPA effects in acute lymphoblastic leukemia (ALL), especially T-cell acute lymphoblastic leukemia (T-ALL), remain unclear. In this study, the antileukemic effects of PSPAs and the underlying molecular mechanisms were evaluated by in vitro and in silico assays. PSPAs extracted from ten cultivars were analyzed and quantified. Anthocyanins from Nanzi 018, which showed the best antileukemic effect, were selected to analyze the underlying mechanism. First, the PSPAs potently reduced cell viability and induced apoptosis. Additionally, the PSPAs sharply increased intracellular Ca 2+ levels, which resulted in calcium overload in T-ALL cells. Furthermore, on the basis of bioinformatics analyses, we focused on an osmotically regulated transcription factor, NFAT5. Molecular docking preliminarily indicated that PSPA molecules bound and interacted with the NFAT5 protein. Western blot analyses confirmed that PSPAs elicited calcium overload by nonosmotic regulation of NFAT5/S100A4-S100A9 pathway activation. Moreover, pretreatment with a NFAT5 inducer confirmed that PSPAs targeted NFAT5 and affected p38/NF-κB/Bcl-2/Caspase-3 axis activation. This study demonstrates that PSPAs exert their antileukemic effects through calcicoptosis induction by targeting NFAT5.

Mouse aortic biomechanics are affected by short-term defective autophagy in vascular smooth muscle cells

The physiology of vascular smooth muscle (VSMC) cells is affected by autophagy, a catabolic cellular mechanism responsible for nutrient recycling. Autophagy-inducing compounds may reverse arterial stiffening, whereas congenital VSMC-specific autophagy deficiency promotes arterial stiffening. The elevated aortic stiffness in 3.5-month-old C57Bl/6 mice, in which the essential autophagy-related gene Atg7 was specifically deleted in the VSMCs (Atg7F/F SM22α-Cre+ mice) was mainly due to passive aortic wall remodeling. The present study investigated whether aortic stiffness was also modulated by a shorter duration of autophagy deficiency. Therefore, aortic segments of 2-month-old Atg7F/F SM22α-Cre+ mice were studied. Similarly to the older mice, autophagy deficiency in VSMCs promoted aortic stiffening by elastin degradation and elastin breaks, and increased the expression of the calcium binding protein S100A4 (+ 157%), the aortic wall thickness (+ 27%), the sensitivity of the VSMCs to depolarization and the contribution of VGCC mediated Ca2+ influx to α1 adrenergic contractions. Hence, all these phenomena occurred before the age of 2 months. When compared to autophagy deficiency in VSMCs at 3.5 months, shorter term autophagy deficiency led to higher segment diameter at 80 mmHg (+ 7% versus - 2%), normal baseline tonus (versus increased), unchanged IP3-mediated phasic contractions (versus enhanced), and enhanced endothelial cell function (versus normal). Overall, and because in vivo cardiac parameters or aortic pulse wave velocity were not affected, these observations indicate that congenital autophagy deficiency in VSMCs of Atg7F/F SM22α-Cre+ mice initiates compensatory mechanisms to maintain circulatory homeostasis.

Ca2+ Signaling as the Untact Mode during Signaling in Metastatic Breast Cancer

Simple Summary

Intracellular Ca²⁺ signaling is a critical factor in breast cancer metastasis. In the proliferation stage, increases in intracellular Ca²⁺ concentration through voltage-dependent Ca²⁺ channels, P₂Y₂ channels, transient receptor potential (TRP) channels, store-operated Ca²⁺ channels (SOCCs), and IP₃ receptors and a decrease in intracellular Ca²⁺ concentration through plasma membrane Ca²⁺ ATPases and secretory pathway Ca²⁺ ATPases (SPCA) activate breast cancer cell proliferation. TRPM7, SOCC, inositol trisphosphate receptor (IP₃R), ryanodine receptor (RyR), and sarco-/endo-plasmic reticulum Ca²⁺-ATPase (SERCA) increase the expression of epithelial-to-mesenchymal transition (EMT)-related proteins; meanwhile, SPCA and the Na⁺/Ca²⁺ exchanger (NCX) control the activation of EMT-related proteins. Increased Ca²⁺ through TRPC1, TRPM7/8, P₂X₇, and SOCC enhances breast cancer cell migration. The stromal interaction molecule (STIM)-Orai complex, P₂X₇, and Ca²⁺ sensing receptors are involved in invadopodia. Various pharmacological agents for Ca²⁺ channels have been proposed against breast cancer and have provided potential strategies for treating metastatic processes.

Abstract

Metastatic features of breast cancer in the brain are considered a common pathology in female patients with late-stage breast cancer. Ca²⁺ signaling and the overexpression pattern of Ca²⁺ channels have been regarded as oncogenic markers of breast cancer. In other words, breast tumor development can be mediated by inhibiting Ca²⁺ channels. Although the therapeutic potential of inhibiting Ca²⁺ channels against breast cancer has been demonstrated, the relationship between breast cancer metastasis and Ca²⁺ channels is not yet understood. Thus, we focused on the metastatic features of breast cancer and summarized the basic mechanisms of Ca²⁺-related proteins and channels during the stages of metastatic breast cancer by evaluating Ca²⁺ signaling. In particular, we highlighted the metastasis of breast tumors to the brain. Thus, modulating Ca²⁺ channels with Ca²⁺ channel inhibitors and combined applications will advance treatment strategies for breast cancer metastasis to the brain.

Development of Potential Antitumor Agents from the Scaffolds of Plant-Derived Terpenoid Lactones

Naturally occurring terpenoid lactones and their synthetic derivatives have attracted increasing interest for their promising antitumor activity and potential utilization in the discovery and design of new antitumor agents. In the present perspective article, selected plant-derived five-membered γ-lactones and six-membered δ-lactones that occur with terpenoid scaffolds are reviewed, with their structures, cancer cell line cytotoxicity and in vivo antitumor activity, structure-activity relationships, mechanism of action, and the potential for developing cancer chemotherapeutic agents discussed in each case. The compounds presented include artemisinin (ART, 1), parthenolide (PTL, 2), thapsigargin (TPG, 3), andrographolide (AGL, 4), ginkgolide B (GKL B, 5), jolkinolide B (JKL B, 6), nagilactone E (NGL E, 7), triptolide (TPL, 8), bruceantin (BRC, 9), dichapetalin A (DCT A, 10), and limonin (LMN, 11), and their naturally occurring analogues and synthetic derivatives. It is hoped that this contribution will be supportive of the future development of additional efficacious anticancer agents derived from natural products.