Deletion of the SPARC acidic domain or EGF-like module reduces SPARC-induced migration and signaling through p38 MAPK/HSP27 in glioma

We previously demonstrated that secreted protein acidic and rich in cysteine (SPARC) increases heat shock protein 27 (HSP27) expression and phosphorylation and promotes glioma cell migration through the p38 mitogen-activated protein kinase (MAPK)/HSP27 signaling pathway. As different regions of the SPARC protein mediate different SPARC functions, elucidating which SPARC domains regulate HSP27 expression, signaling and migration might provide potential therapeutic strategies to target these functions. To investigate the roles of specific domains, we used an SPARC-green fluorescent protein (GFP) fusion protein and constructs of SPARC-GFP with deletions of either the acidic domain (ΔAcidic) or the epidermal growth factor (EGF)-like module (ΔEGF). GFP, SPARC-GFP and the two deletion mutants were expressed in U87MG glioma cells. Characterization of the derived stable clones by confocal imaging and western blotting suggests proper folding, processing and secretion of the deletion constructs. Uptake of the constructs by naive cells suggests enhanced internalization of ΔAcidic and reduced internalization of ΔEGF. Wound and transwell migration assays and western blot analysis confirm our previous results and indicate that ΔAcidic reduces SPARC-induced migration and p38 MAPK/HSP27 signaling and ΔEGF decreases SPARC-induced migration and dramatically decreases the expression and phosphorylation of HSP27 but is poorly internalized. Loss of the EGF-like module suppresses the enhanced HSP27 protein stability conferred by SPARC. In conclusion, deletions of the acidic domain and EGF-like module have differential effects on cell surface binding and HSP27 protein stability; however, both regions regulate SPARC-induced migration and signaling through HSP27. Our data link the domains of SPARC with different functions and suggest one or both of the constructs as potential therapeutic agents to inhibit SPARC-induced migration.     

Hsp90抑制剂NVP-AUY922单药及联合用药在肿瘤治疗中的研究进展

热休克蛋白(Hsp90)是一类高度保守的蛋白质。近年的研究表明,Hsp90与肿瘤的发生及转移有高度的相关性,因此一些小分子Hsp90抑制剂被发现具有广泛的抗肿瘤增殖及转移的作用。NVP-AUY922是其中一种具有吡咯骨架的人工合成制剂,由于它具有毒副作用小和结构稳定等优点,被人们广泛考虑作为新一类的抗肿瘤药物使用。本篇综述主要就AUY922单药及与其他药物联合使用治疗肿瘤的研究进展做一综述。     

AKT inhibition by triciribine alone or as combination therapy for growth control of gastroenteropancreatic neuroendocrine tumors

Up-regulation of phosphatidylinositol-3-kinase (PI3K)-AKT signaling facilitates tumor cell growth and inhibits cell demise. The AKT-pathway also plays an important role in cytostatic therapy resistance and response to hypoxia and angiogenesis. Using real-time cell proliferation assay we examined the potency of triciribine in three distinct neuroendocrine gastrointestinal tumor cell lines. Also we investigated triciribine's induction of apoptosis and effects on a broad range of cancer-associated gene products. Furthermore, we characterized the role of PTEN as a possible predictor of sensitivity to triciribine in GEP-NETs. We also looked for additive anti-neoplastic effects of triciribine when combined with conventional cytostatic drugs or other targeted drugs, affecting different molecules of the PI3K-AKT-pathway and we assessed the potency of triciribine to inhibit tumor growth in vivo, by using the chick chorioallantoic membrane assay. Treatment of insulinoma (CM) or gut neuroendocrine tumor cells (STC-1) with triciribine significantly reduced tumor cell growth by 59% and 65%, respectively. By contrast, the highly expressing PTEN carcinoid cell line BON did not respond, even at higher doses. Combinations of triciribine with classic cytostatic drugs as well as drugs targeting other molecules of the PI3K-AKT-pathway led to synergistic anti-proliferative effects. Additional in vivo-evaluations confirmed the anti-neoplastic potency of triciribine. Thus, our data show that inhibition the AKT-pathway potently reduces the growth of GEP-NET cells alone or in combination therapies. AKT inhibition may provide a rationale for future evaluations.     

Hedgehog pathway inhibition as a therapeutic target in acute myeloid leukemia

Introduction: The Hedgehog (HH) pathway constitutes a collection of signaling molecules which critically influence embryogenesis. In adults, however, the HH pathway remains integral to the proliferation, maintenance, and apoptosis of adult stem cells including hematopoietic stem cells.

Areas covered: We discuss the current understanding of the HH pathway as it relates to normal hematopoiesis, the pathology of acute myeloid leukemia (AML), the rationale for and data from combination therapies including HH pathway inhibitors, and ultimately the prospects that might offer promise in targeting this pathway in AML.

Expert opinion: Efforts to target the HH pathway have been focused on impeding this disposition and restoring chemosensitivity to conventional myeloid neoplasm therapies. The year 2018 saw the first approval of a HH pathway inhibitor (glasdegib) for AML, though for an older population and in combination with an uncommonly-used therapy. Several other clinical trials with agents targeting modulators of HH signaling in AML and MDS are underway. Further study and understanding of the interplay between the numerous aspects of HH signaling and how it relates to the augmented survival of AML will provide a more reliable substrate for therapeutic strategies in patients with this poor-risk disease.     

AMPK as a therapeutic target in renal cell carcinoma

AMPK is a cellular energy sensor that negatively regulates the mTOR signaling pathway. As mTOR plays critical roles in cell growth and tumorigenesis of renal cell carcinoma (RCC), we examined whether exogenous induction of AMPK activity exhibits inhibitory effects on growth and survival of renal cell carcinoma cells. Activation of AMPK by AICAR resulted in potent suppressive effects on RCC growth, while combinations of AICAR with statins were potent inducers of apoptosis in such cells. The effects of AICAR resulted from inhibition of mTOR and its effectors, resulting from induction of AMPK activity. Similar results on RCC cell growth were obtained when combinations of metformin with statins were examined. Importantly, studies to examine the effects of AICAR or metformin, alone or in combinations with statins, on anchorage-independent growth demonstrated potent suppressive effects on RCC tumorigenicity in vitro. Altogether, our studies demonstrate that AMPK plays critical regulatory roles in the regulation of growth of RCC cells and raise the prospect of future use of AMPK activators in the treatment of renal cell carcinoma in humans.     

Clinical experience with lenalidomide alone or in combination with rituximab in indolent B-cell and mantle cell lymphomas

Lenalidomide is an oral immunomodulatory drug with significant activity in indolent B-cell and mantle cell lymphomas. Lenalidomide has a manageable safety profile whether administered as a single agent or in combination with rituximab. The combination of lenalidomide with rituximab, known as the ‘R²’ regimen, enhances efficacy over what has been shown with monotherapy and has demonstrated activity in patients considered resistant to rituximab. Tolerability of these regimens has been consistent among studies. Asymptomatic neutropenia is the most common grade 3/4 adverse event, typically managed by dose interruption, followed by dose reduction once neutrophils have recovered. Nonhematologic toxicities (e.g. fatigue) are generally low-grade, manageable with concomitant treatment, and/or lenalidomide dose modification. More frequent with R², immune-related symptoms such as rash and tumor flare are important to recognize as lenalidomide-associated treatment effects in patients with lymphoma who require supportive care and potential dose modifications. Severe tumor flare reactions with painful lymphadenopathy are not typically observed outside of chronic lymphocytic leukemia/small lymphocytic lymphoma. Venous thromboembolism is uncommon in lymphomas, though prophylaxis is recommended. The general safety profile, differences between lenalidomide monotherapy and R² treatment, and optimal strategies for managing adverse events are discussed here.     

Efficacy of system l amino acid transporter 1 inhibition as a therapeutic target in esophageal squamous cell carcinoma

System l amino acid transporter 1 (LAT1) is highly expressed in various types of human cancer, and contributes to cancer growth and survival. Recently, we have shown that LAT1 expression is closely related to the growth and aggressiveness of esophageal cancer, and is an independent marker of poor prognosis. However, it remains unclear whether LAT1 inhibition could suppress esophageal cancer growth. In this study, we investigated the tumor‐suppressive effects of the inhibition of LAT1. Both LAT1 and CD98, which covalently associates to LAT1 on the membrane, were expressed in human esophageal cancer cell lines KYSE30 and KYSE150. Quantitative PCR analysis showed that the expression of LAT1 was much higher than other subtypes of LAT. A selective inhibitor of LAT, 2‐aminobicyclo‐(2,2,1)‐heptane‐2‐carboxylic acid (BCH), suppressed cellular uptake of l ‐¹⁴C‐leucine and cell proliferation in a dose‐dependent manner. It also suppressed phosphorylation of mammalian target of rapamycin, 4E‐BP1, and p70S6K protein, and induced cell cycle arrest at G₁ phase. These results suggest that suppression of both mammalian target of rapamycin signaling and cell cycle progression is involved in BCH‐induced growth inhibition. In tumor‐bearing mice, daily treatment with BCH significantly delayed tumor growth and decreased glucose metabolism, indicating that LAT1 inhibition potentially suppresses esophageal cancer growth in vivo. Thus, our results suggest that LAT1 inhibition could be a promising molecular target for the esophageal cancer therapy.     

Thrombogenicity of intravenous 5-fluorouracil alone or in combination with cisplatin

Acute myocardial infarction was observed in two patients receiving standard intravenous doses of 5-fluorouracil (5-FU)-based chemotherapy. Therefore, the authors prospectively assessed the thrombogenicity of this agent by studying ten patients, six with head and neck cancer and four with gastrointestinal malignancies, receiving 5-FU (1 g/m2/day) as a constant intravenous infusion over a 4-day or 5-day period. The six patients with head and neck cancer also received a single dose of 100 mg/m2 of cisplatin on day 1. Blood samples were obtained preinfusion, 24 hours into the infusion, and postinfusion. Samples were assayed for fibrinopeptide A (FpA) by enzyme-linked immunoassay, for protein C activity (PCa) using a chromogenic substrate (Spectrozyme PCa), and protein C (PCag) and free protein S antigen (PSag) by electroimmunoassay. No patient experienced a thrombotic event. A significant increase was observed in FpA levels during the infusion which returned toward baseline at the conclusion of the infusion. After infusion of 5-FU, the PCa value was significantly lower than the PCag (37 +/- 17 versus 69 +/- 24%; P less than 0.002). No effect on protein S was observed. The changes in the patients receiving 5-FU alone were comparable to those who also received CDDP. The authors conclude that during the infusion of 5-FU, the rise in FpA activation and reduction in PCa as compared to PCag are compatible with activation of coagulation.     

Antileukaemia effect of rapamycin alone or in combination with daunorubicin on ph+ acute lymphoblastic leukaemia cell line

The translocation (9;22) (q34;q11), known as the Philadelphia (Ph) chromosome and bcr-abl fusion gene, is the common cytogenetic abnormality and an unfavourable prognosis in adult acute lymphoblastic leukaemia (ALL). Although chemotherapeutic treatment produced high rates of complete response in approximately 70%-80% of newly diagnosed Ph+ ALL, the onset of resistance and clinical relapse is rapid. Therefore, the efficacy of treatment in Ph+ ALL is still to be determined. In this study, we aimed to assess the antileukemic activity of rapamycin (RAPA) (Sigma-Aldrich Corporation, MO, USA), a mammalian target of rapamycin inhibitor, alone and in combination with daunorubicin (DNR) (Pharmacia & Upjohn Company, Germany) in a Ph+ acute lymphoblastic cell line SUP-B15 and a primary Ph+ ALL sample in vitro. Here, we demonstrated that 50 nmol/L of RAPA significantly intensified the inhibition induced by DNR on both Ph+ ALL cell line and a primary Ph+ ALL sample. Notably, we reported that the consequence of DNR treatment induced the over expression of the components of mammalian target of rapamycin signalling pathway, whereas RAPA effectively eliminated this deleterious side effect of DNR, which might enhance DNR's ability to kill drug-resistant cancer. The synergistic effect was also associated with the increase in autophagy, blockage of cell cycle progression in the G1 phase. Altogether, our results suggest that DNR in combination with RAPA is more effective in the treatment of Ph+ ALL compared with DNR alone.     

Selective PI3K inhibition by BKM120 and BEZ235 alone or in combination with chemotherapy in wild-type and mutated human gastrointestinal cancer cell lines

Purpose

New targeted agents like antibodies or small molecules against tyrosine and lipid kinases clearly expand the standard therapy options in oncology. However, tumour resistance is still a challenge, often induced by mutations in growth-related signalling cascades. Twenty and ten percentage of all patients with colorectal and gastric cancers, respectively, carry phosphatidyl-3-kinase (PI3K) mutations and do not respond to receptor-blocking therapies. Recently, selective kinase inhibitors have been generated, which block the PI3K signalling pathway in tumour cells. So far, their therapeutic role for the treatment of mutated versus wild-type human gastrointestinal cancers has not been clarified in detail.

Methods

To define the inhibitory and pro-apoptotic effects of the two PI3K inhibitors BEZ235 and BKM120 in three human colon cancer (HT-29, HCT-116 and DLD-1) and three gastric cancer (NCI-n87, AGS and MKN-45), cell lines with different PIK3CA gene mutation status were used. Firstly, viability, apoptosis and caspase assays were performed during incubation with either the inhibitors alone or combined with different cytotoxic agents. Secondly, the molecular consequences for the cell cycle and signalling pathways were analysed by defining the protein levels by FACS and Western blot analysis.

Results

Both the PI3K inhibitors BEZ235 and BKM120 induced a clear concentration-dependent reduction in cell viability and an increase in apoptotic cell death, with the mutated cells being more sensitive to treatment. However, single-agent BEZ235 caused a G1 arrest in tumour cells, whilst BKM120 induced a G2 shift in a half of the gastrointestinal cancer cell lines. There was a clear downregulation in the protein levels of the PI3K–AKT pathway at the concentrations of 100nM for both agents and for BEZ235 the additional inhibition of the mTOR pathway. Furthermore, BEZ235 caused synergistic induction of apoptosis when combined with irinotecan in colon cancer cell lines. Human gastric cancer cells were less sensitive to both BEZ235 and BKM120.

Conclusions

BEZ235 and BKM120 induced pro-apoptotic effects in all cell lines and especially with an increased response in the PI3KCA mutated cells. Our data support the clinical development of these PI3K inhibitors for patients with wild-type or mutated colon cancers.     

奥希替尼联合抗血管生成靶向药对人肺腺癌细胞抑制作用的实验研究

目的:通过体外细胞学实验初步探究奥希替尼联合两种不同机制的抗血管靶向治疗药物（贝伐珠单抗或阿帕替尼）治疗表皮生长因子受体（EGFR）敏感突变和T790M耐药突变肺腺癌细胞的抗肿瘤活性及其作用机制。方法:培养人肺腺癌细胞PC-9（E19 del）和H1975（E21 L858R/E20 T790M）,CCK-8法检测奥希替尼及抗血管靶向治疗药物（贝伐珠单抗或阿帕替尼）单药或联合处理肺腺癌细胞48 h后的抑瘤率;蛋白质印迹法检测EGFR及其下游AKT和ERK信号通路蛋白表达情况。结果:PC-9和H1975肺腺癌细胞对奥希替尼敏感且呈剂量依赖性。奥希替尼联合抗血管生成靶向药物（贝伐珠单抗,阿帕替尼）较同等浓度的单药奥希替尼可增加对PC-9和H1975细胞株的抑瘤率（P<0.05）。低浓度奥希替尼联合高浓度阿帕替尼（1 000 nmol/L）的抑制作用与高浓度奥希替尼相当（P>0.05）。随着联合的阿帕替尼浓度的升高,对PC-9和H1975细胞抑瘤率也有一定程度的提高（P<0.05）。不同处理因素对PC-9细胞的抑制率均高于对H1975细胞（P<0.01）。随着奥希替尼浓度的上升,p-EGFR、p-AKT、p-ERK磷酸化蛋白表达逐渐降低。结论:奥希替尼联合贝伐珠单抗或阿帕替尼会进一步增强对EGFR敏感突变或T790M突变肺腺癌细胞的杀伤作用。奥希替尼与阿帕替尼联合使用具有很强的抑瘤活性,具有很好的应用前景。奥希替尼单药或与抗血管形成药联合作用可能是进一步下调EGFR及其下游AKT和ERK信号通路的活化。     

地昔帕明单用和合用替尼泊苷对大鼠脑胶质瘤C6细胞增殖的调控作用

目的：研究三环类抗抑郁药地昔帕明（ＤＭ）对脑胶质瘤Ｃ６细胞增殖的调控作用,并探讨与临床常用治疗脑瘤的化疗药物替尼泊苷（ＶＭ－２６）合用的协同效应。方法：采用ＭＴＴ比色法测定大鼠脑胶质瘤Ｃ６细胞增殖抑制作用和流式细胞术（ＦＣＭ）进行细胞周期分析。结果：ＤＭＩ（１０－８０μｍｏｌ／Ｌ）对Ｃ６细胞的增殖具有明显的抑制作用,呈浓度时间依赖关系,药物作用２４ｈ的ＩＣ５０（９５％置信区间）为２０．７（１７．３     

In vitro studies of baicalin alone or in combination with Salvia miltiorrhiza extract as a potential anti-cancer agent

Traditional Chinese herbal medicines (TCM) that for centuries have been used in disease prevention and treatment are finding use as alternatives to Western cancer therapies. From a panel of TCM, we chose four compounds representing two functional classes of botanicals, the purified plant flavins scutellarin (a circulatory stimulant) and baicalin (antipyretic), and two extracts purified from Salvia miltiorrhiza (SM-470, circulatory stimulant) and Camellia sinensis (Cam-300, antipyretic), and examined their anti-proliferation effects on the human breast cancer cell lines MCF-7 and T-47D. All four compounds inhibited MCF-7 and T-47D cell proliferation, baicalin being the most potent inhibitor. Moreover, the combination of compounds from different classes offers enhanced potential therapeutic benefits; the combination of SM-470 with scutellarin, Cam-300 or baicalin, augmented the inhibition of cell proliferation. A synergistic inhibitory effect on MCF-7 cell proliferation was also observed when SM-470 and baicalin were applied together. In contrast, inhibition of T-47D cell proliferation using the same combination was dependent on baicalin only. The anti-proliferative effects of these compounds can be extended to other cancer types; the human head and neck cancer epithelial cell lines CAL-27 and FaDu were also sensitive to the four drugs. Overall, SM-470, Cam-300, scutellarin and baicalin inhibited the proliferation of human breast cancer cells and CAL-27 and FaDu cells with different potency. Baicalin and SM-470 in combination produced additive effects, suggesting these compounds may function by different mechanisms. T-47D, MCF-7, and FaDu cells may be useful in exploring the cellular and molecular mechanisms of action of baicalin and SM-470.     

Prognostic significance of heat shock protein 27 (HSP27) in patients with oral squamous cell carcinoma

Heat shock proteins (HSPs) have been defined as proteins induced by heat shock and other environmental and pathophysiologic stress. Heat shock protein 27 (HSP27) is one of the small heat shock proteins. HSP27 is implicated in protein-protein interactions such as folding, translocation, and prevention of inappropriate protein aggregation. Many of their functions suggest that they play important roles in cancers. Archival tissues from 40 patients with oral squamous cell carcinoma who received primary surgical resection were examined for HSP27 by immunohistochemistry and correlated with clinical stage, lymph node metastasis, histological grade and survival period. HSP27 expression was positive staining (+) in 20 (50%), weak or negative staining (-) in 20 (50%) of total 40 cases. There was no correlation between HSP27 expression and clinical stage, lymph node metastasis and histological grade. However, when compared with clinicopathological features, the expression of HSP27 correlated inversely with survival period. This study suggests that the expression of HSP27 is frequently promoted in patients with oral squamous cell carcinoma and should be considered an independent prognostic factor of oral squamous cell carcinoma patients.