Xiu-Li Guo

Serum Galectin-2, -4, and -8 Are Greatly Increased in Colon and Breast Cancer Patients and Promote Cancer Cell Adhesion to Blood Vascular Endothelium

Purpose: Adhesion of disseminating tumor cells to the blood vascular endothelium is a pivotal step in metastasis. Previous investigations have shown that galectin-3 concentrations are increased in the bloodstream of patients with cancer and that galectin-3 promotes adhesion of disseminating tumor cells to vascular endothelium in vitro and experimental metastasis in vivo. This study determined the levels of galectin-1, -2, -3, -4, -8, and -9 in the sera of healthy people and patients with colon and breast cancer and assessed the influence of these galectins on cancer-endothelium adhesion. Experimental Design: Serum galectins and auto–anti-MUC1 antibodies were assessed using ELISA and mucin protein (MUC1) glycan microarrays, and cancer-endothelium adhesion was determined using monolayers of human microvascular lung endothelial cells. Results: The levels of serum galectin-2, -3, -4, and -8 were significantly increased up to 31-fold in patients with cancer and, in particular, those with metastases. As previously shown for galectin-3, the presence of these galectins enhances cancer-endothelium adhesion by interaction with the Thomsen-Friedenreich (TF; Galβ1,3GalNAcα-) disaccharide on cancer-associated MUC1. This causes MUC1 cell surface polarization, thus exposing underlying adhesion molecules that promote cancer-endothelium adhesion. Elevated circulating galectin-2 levels were associated with increased mortality in patients with colorectal cancer, but this association was suppressed when anti-MUC1 antibodies with specificity for the TF epitope of MUC1 were also present in the circulation. Conclusions: Increased circulation of several members of the galectin family is common in patients with cancer and these may, like circulating galectin-3, also be involved in metastasis promotion. Clin Cancer Res; 17(22); 7035–46. ©2011 AACR.

MMP-9, a Potential Target for Cerebral Ischemic Treatment

Matrix metalloproteinase-9 (MMP-9) which is a member of matrix metalloproteinases family that normally remodel the extracellular matrix, has been shown to play an important role in both animal models of cerebral ischemia and human stroke. The expression of MMP-9 is elevated after cerebral ischemia which is involved in accelerating matrix degradation, disrupting the blood-brain barrier, increasing the infarct size and relating to hemorrhagic transformation. Recently, many drugs, such as tetracycline derivatives, cyclooxygenase inhibitors, ACEI inhibitors and AT1 receptor blockers, etc., have been found to attenuate the elevated expression levels of MMP-9 after ischemia and to reduce the damage of cerebral ischemic. This article reviews the physiological features of MMP-9 and its important role in the genesis, propagation, and therapeutics of cerebral ischemic diseases.

Plagiochin E, a botanic-derived phenolic compound, reverses fungal resistance to fluconazole relating to the efflux pump.

Aim:  In this study, we investigated the effect of plagiochin E (PLE), a botanic‐derived phenolic natural product, on reversal of fungal resistance to fluconazole (FLC) in vitro and the related mechanism.

Cytoprotective effects of CSTMP, a novel stilbene derivative, against H2O2-induced oxidative stress in human endothelial cells.

A novel stilbene derivative, (E)-2-(2-chlorostyryl)-3,5,6-trimethylpyrazine (CSTMP), was designed and synthesized based on the pharmacophores of tetramethylpyrazine (TMP) and resveratrol (RES). In the present study, we investigated the protective effects of CSTMP on vascular endothelial cells under oxidative stress and elucidated its molecular mechanisms. The radical scavenging activity of CSTMP was assessed by the DPPH test. Human Umbilical Vein Endothelial Cells (HUVECs) were exposed to 150 μM hydrogen peroxide (H(2)O(2)) for 12 h, resulting in a decrease of cell viability assessed by the MTT assay and an increase of apoptotic cells assessed by the nuclear staining assay and flow cytometry. The activities of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and nitric oxide synthase (NOS) and the contents of malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (NO) in cells were determined by commercial kits. The expression levels of pro-apoptotic factor caspase-3 and anti-apoptotic signal ERK1/2 were detected by western blot. The results showed that CSTMP had a moderate anti-oxidative effect against the DPPH test, which was less than RES. Co-incubation with CSTMP increased the cell viability, markedly reduced the LDH leakage from the cells and decreased the lipid peroxidation. These effects of CSTMP were accompanied by increasing activity of the endogenous antioxidant enzyme SOD, the level of GSH, the production of NO and cNOS activity. Moreover, CSTMP showed stronger effects on the inhibition of apoptosis, caspase-3 expression, and the activation of phosphorylated ERK1/2 compared to RES. Furthermore, CSTMP could inhibit the expression of phospho-JNK and phospho-p38 induced by H(2)O(2). These results suggest that CSTMP prevents H(2)O(2)-induced cell injury through anti-oxidation and anti-apoptosis via the MAPK and caspase-3 pathways.

Combinational strategies of metformin and chemotherapy in cancers

Chemotherapeutic regimens are the most common treatment to inhibit tumor growth, but there is great variability in clinical responses of cancer patients; cancer cells often develop resistance to chemotherapeutics which results in tumor recurrence and further progression. Metformin, an extensively prescribed and well-tolerated first-line therapeutic drug for type 2 diabetes mellitus, has recently been identified as a potential and attractive anticancer adjuvant drug combined with chemotherapeutic drugs to improve treatment efficacy and lower doses. In this review, we summarized the molecular mechanisms underlying anticancer effects of metformin, which included insulin- and AMPK-dependent effects, selectively targeting cancer stem cells, reversing multidrug resistance, inhibition of the tumor metastasis and described the antineoplastic effects of metformin combined with chemotherapeutic agents in digestive system cancers (colorectal, gastric, hepatic and pancreatic cancer), reproductive system cancers (ovarian and endometrial cancer), prostate cancer, breast cancer, lung cancer, etc. Moreover, the clinical trials regarding metformin in combination of chemotherapeutic drugs were presented and the clinical obstacle or limitation related to the potential role of metformin in cancer treatment was also discussed in this review.

Inhibition of PTEN expression and activity by angiotensin II induces proliferation and migration of vascular smooth muscle cells.

PTEN (phosphatase and tensin homolog deleted on chromosome 10) is a tumor suppressor and has been suggested recently to be involved in the regulation of cardiovascular diseases. The molecular mechanisms of this regulation are however poorly understood. This study shows that down regulation of PTEN expression and activity by angiotensin II (Ang II) increased proliferation and migration of vascular smooth muscle cells (VSMCs). The presence of Ang II induced rapid PTEN phosphorylation and oxidation in accordance with increased AKT and FAK phosphorylation. The Ang II‐mediated VSMC proliferation and migration was inhibited when cellular PTEN expression was increased by AT1 inhibitor losartan, PPARγ agonist rosiglitazone, NF‐κB inhibitor BAY 11‐7082. Over expression of PTEN in VSMCs by adenovirus transduction also resulted in inhibition of cell proliferation and migration in response to Ang II. These results suggest that PTEN down‐regulation is involved in proliferation and migration of VSMCs induced by Ang II. This provides insight into the molecular regulation of PTEN in vascular smooth muscle cells and suggests that targeting the action of PTEN may represent an effective therapeutic approach for the treatment of cardiovascular diseases. J. Cell. Biochem. 114: 174–182, 2012.

Design, Synthesis, and Biological Evaluation of 1-Methyl-1,4-dihydroindeno[1,2-c]pyrazole Analogues as Potential Anticancer Agents Targeting Tubulin Colchicine Binding Site

By targeting a new binding region at the interface between αβ-tubulin heterodimers at the colchicine binding site, we designed a series of 7-substituted 1-methyl-1,4-dihydroindeno[1,2-c]pyrazoles as potential tubulin polymerization inhibitors. Among the compounds synthesized, 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)acetamide 6a and 2-(6-ethoxy-3-(3-ethoxyphenylamino)-1-methyl-1,4-dihydroindeno[1,2-c]pyrazol-7-yloxy)-N-hydroxyacetamide 6n showed noteworthy low nanomolar potency against HepG2, Hela, PC3, and MCF-7 cancer cell lines. In mechanism studies, 6a inhibited tubulin polymerization and disorganized microtubule in A549 cells by binding to tubulin colchicine binding site. 6a arrested A549 cells in G2/M phase that was related to the alterations in the expression of cyclin B1 and p-cdc2. 6a induced A549 cells apoptosis through the activation of caspase-3 and PARP. In addition, 6a inhibited capillary tube formation in a concentration-dependent manner. In nonsmall cell lung cancer xenografts mouse model, 6a suppressed tumor growth by 59.1% at a dose of 50 mg/kg (ip) without obvious toxicity, indicating its in vivo potential as anticancer agent.

Role of the interaction between galectin-3 and cell adhesion molecules in cancer metastasis

Galectin-3, a unique chimera-type member of the β-galactoside-binding soluble lectin family, is present in both normal and cancer cells and plays a crucial role in the regulation of cell adhesion. It is involved both in accelerating detachment of cells from primary tumor sites and promoting cancer cell adhesion and survival to anoikis in the blood stream. Cell adhesion molecules (CAMs) are membrane receptors that mediate cell-cell and cell-matrix interactions, and are essential for transducing intracellular signals responsible for adhesion, migration, invasion, angiogenesis, and organ-specific metastasis. This review will discuss the recent advances in our understanding the biological functions, mechanism and therapeutic implication of the interaction between galectin-3 and CAMs in cancer metastasis.

Ligustrazine derivatives. Part 4: design, synthesis, and biological evaluation of novel ligustrazine-based stilbene derivatives as potential cardiovascular agents.

A series of novel stilbene derivatives containing ligustrazinyl moiety was designed, synthesized, and assayed for their protective effects on damaged endothelial cells. The results showed that most ligustrazinyl stilbene derivatives exhibited high protective effects on the human umbilical vascular endothelial cells (HUVECs) damaged by hydrogen peroxide in comparison with Ligustrazine. The stilbene derivatives A6, A9, A11, A21, A24, A25, and A27 exhibited high potency with low EC50 values ranged from 0.0249 μm to 0.0898 mm. Compound A27 displayed EC50 0.0249 μm, which is 30 000 times higher than that of Ligustrazine, presenting a most promising lead for further investigation. Structure–activity relationships were briefly discussed.

Sorcin, a potential therapeutic target for reversing multidrug resistance in cancer

Sorcin (soluble resistance-related calcium-binding protein) is a 21.6-kDa calcium-binding protein [13] and is also called V19 [25], p21 [23], the 22-kD polypeptide [41] or CP22 [17]. It is first synthesized in vincristine-resistant Chinese hamster cells (DC-3F/ VCRd-5) by Meyers and Biedler in 1981 [24]. Sorcin belongs to the penta-EF-hand (PEF) family which includes also calpains, grancalcin, ALG-2, and peflin [6]. The binding of Ca triggers the reversible translocation of all PEF proteins from the cytoplasm to cell membranes where they interact with specific target proteins and participate in a variety of physiological processes. Sorcin has been recently identified in a wide variety of human cells, such as cardiac cells, vascular smooth cells, adrenal medulla, and tumor cells [1, 8]. In cardiac cells and vascular smooth cells, sorcin interacts with the cardiac ryanodine receptor-2 (RyR2) and Ltype Ca current to modulate calcium balance [9, 16, 31]. In adrenal medulla, sorcin binds to synexin (annexin VII) and inhibits synexin-mediated calciumdependent chromaffin granule aggregation [3, 42]. In addition, sorcin has been identified in many tumor cells, such as leukemia, gastric cancer, breast cancer, ovarian cancer, etc. [4, 7, 28, 29, 48]. Sorcin is found to be expressed more in the resistant cell lines suggesting that sorcin might be a useful therapeutic target for reversing tumor multidrug resistance. The role of sorcin in drug resistance is still unclear. It is known though that the sorcin level does not correlate with the degree of drug resistance [38]. This review summaries the recent understanding of the structures, biological functions, regulations, and roles of sorcin in tumor drug resistance.