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1.
The molecular chaperone GRP78/BiP is a key regulator of protein folding in the endoplasmic reticulum, and it plays a pivotal role in cancer cell survival and chemoresistance. Inhibition of its function has therefore been an important strategy for inhibiting tumor cell growth in cancer therapy. Previous efforts to achieve this goal have used peptides that bind to GRP78/BiP conjugated to pro-drugs or cell-death-inducing sequences. Here, we describe a peptide that induces prostate tumor cell death without the need of any conjugating sequences. This peptide is a sequence derived from the cochaperone Bag-1. We have shown that this sequence interacts with and inhibits the refolding activity of GRP78/BiP. Furthermore, we have demonstrated that it modulates the unfolded protein response in ER stress resulting in PARP and caspase-4 cleavage. Prostate cancer cells stably expressing this peptide showed reduced growth and increased apoptosis in in vivo xenograft tumor models. Amino acid substitutions that destroyed binding of the Bag-1 peptide to GRP78/BiP or downregulation of the expression of GRP78 compromised the inhibitory effect of this peptide. This sequence therefore represents a candidate lead peptide for anti-tumor therapy.  相似文献   

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The formation of liver metastases in colorectal cancer patients is the primary cause of patient death. Current therapies directed at liver metastasis from colorectal cancer have had minimal impact on patient outcomes. Therefore, the development of alternative treatment strategies for liver metastasis is needed. In the present study, we demonstrated that recombinant human apolipoprotein(a) kringle V, also known as rhLK8, induced the apoptotic turnover of endothelial cells in vitro through the mitochondrial apoptosis pathway. The interaction of rhLK8 with glucose-regulated protein 78 (GRP78) may be involved in the induction of apoptosis because the inhibition of GRP78 by GRP78-specific antibodies or siRNA knockdown inhibited the rhLK8-mediated apoptosis of human umbilical vein endothelial cells in vitro. Next, to evaluate the effects of rhLK8 on angiogenesis and metastasis, an experimental model of liver metastasis was established by injecting a human colorectal cancer cell line, LS174T, into the spleens of BALB/c nude mice. The systemic administration of rhLK8 significantly suppressed liver metastasis from human colorectal cancer cells and improved host survival compared with controls. The combination of rhLK8 and 5-fluorouracil substantially increased these survival benefits compared with either therapy alone. Histological observation showed significant induction of apoptosis among tumor-associated endothelial cells in liver metastases from rhLK8-treated mice compared with control mice. Collectively, these results suggest that the combination of rhLK8 with conventional chemotherapy may be a promising approach for the treatment of patients with life-threatening colorectal cancer liver metastases.  相似文献   

4.
Various vascular-targeted agents fused with tumor necrosis factor α (TNFα) have been shown to improve drug absorption into tumor tissues and enhance tumor vascular function. TCP-1 is a peptide selected through in vivo phage library biopanning against a mouse orthotopic colorectal cancer model and is a promising agent for drug delivery. This study further investigated the targeting ability of TCP-1 phage and peptide to blood vessels in an orthotopic gastric cancer model in mice and assessed the synergistic anti-cancer effect of 5-fluorouracil (5-FU) with subnanogram TNFα targeted delivered by TCP-1 peptide. In vivo phage targeting assay and in vivo colocalization analysis were carried out to test the targeting ability of TCP-1 phage/peptide. A targeted therapy for improvement of the therapeutic efficacy of 5-FU and vascular function was performed through administration of TCP-1/TNFα fusion protein in this model. TCP-1 phage exhibited strong homing ability to the orthotopic gastric cancer after phage injection. Immunohistochemical staining suggested that and TCP-1 phage/TCP-1 peptide could colocalize with tumor vascular endothelial cells. TCP-1/TNFα combined with 5-FU was found to synergistically inhibit tumor growth, induce apoptosis and reduce cell proliferation without evident toxicity. Simultaneously, subnanogram TCP-1/TNFα treatment normalized tumor blood vessels. Targeted delivery of low-dose TNFα by TCP-1 peptide can potentially modulate the vascular function of gastric cancer and increase the drug delivery of chemotherapeutic drugs.  相似文献   

5.
Rapidly growing tumors require efficient means to allow them to adapt to fluctuating microenvironments consisting of hypoxia, nutrient deprivation, and acidosis. The unfolded protein response (UPR) represents a defense mechanism allowing cells to respond to these adverse conditions. The chaperone protein GRP78 serves as a master UPR regulator that is aberrantly expressed in a variety of cancers, including glioma. Therefore, cancer cells may be particularly reliant upon the adaptive mechanisms offered by the UPR and targeting GRP78 may represent a unique therapeutic strategy. Here we report that diffuse expression of GRP78 protein is present in Grade III-IV, but not Grade I-II glioma. To determine the role GRP78 plays in glioblastoma tumorigenesis, we explored the anti-tumor activity of the novel fusion protein EGF-SubA, which combines EGF with the cytotoxin SubA that has been recently shown to selectively cleave GRP78. EGF-SubA demonstrated potent tumor-specific proteolytic activity and cytotoxicity in glioblastoma lines and potentiated the anti-tumor activity of both temozolomide and ionizing radiation. To determine if the tumor microenvironment influences EGF-SubA activity, we maintained cells in acidic conditions that led to both UPR activation and increased EGF-SubA induced cytotoxicity. EGF-SubA was well tolerated in mice and led to a significant tumor growth delay in a glioma xenograft mouse model. The UPR is emerging as an important adaptive pathway contributing to glioma tumorigenesis. Targeting its primary mediator, the chaperone protein GRP78, through specific, proteolytic cleavage with the immunotoxin EGF-SubA represents a novel and promising multi-targeted approach to cancer therapy.  相似文献   

6.
Heat shock protein 90 (HSP90) inhibitors are potential drugs for cancer therapy. The inhibition of HSP90 on cancer cell growth largely through degrading client proteins, like Akt and p53, therefore, triggering cancer cell apoptosis. Here, we show that the HSP90 inhibitor 17-AAG can induce the expression of GRP75, a member of heat shock protein 70 (HSP70) family, which, in turn, attenuates the anti-growth effect of HSP90 inhibition on cancer cells. Additionally, 17-AAG enhanced binding of GRP75 and p53, resulting in the retention of p53 in the cytoplasm. Blocking GRP75 with its inhibitor MKT-077 potentiated the anti-tumor effects of 17-AAG by disrupting the formation of GRP75-p53 complexes, thereby facilitating translocation of p53 into the nuclei and leading to the induction of apoptosis-related genes. Finally, dual inhibition of HSP90 and GRP75 was found to significantly inhibit tumor growth in a liver cancer xenograft model. In conclusion, the GRP75 inhibitor MKT-077 enhances 17-AAG-induced apoptosis in HCCs and increases p53-mediated inhibition of tumor growth in vivo. Dual targeting of GRP75 and HSP90 may be a useful strategy for the treatment of HCCs.  相似文献   

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Background

A proliferation-inducing ligand (APRIL) is a member of the tumor necrosis factor (TNF) super family. It binds to its specific receptors and is involved in multiple processes during tumorigenesis and tumor cells proliferation. High levels of APRIL expression are closely correlated to the growth, metastasis, and 5-FU drug resistance of colorectal cancer. The aim of this study was to identify a specific APRIL binding peptide (BP) able to block APRIL activity that could be used as a potential treatment for colorectal cancer.

Methods

A phage display library was used to identify peptides that bound selectively to soluble recombinant human APRIL (sAPRIL). The peptides with the highest binding affinity for sAPRIL were identified using ELISA. The effects of sAPRIL-BP on cell proliferation and cell cycle/apoptosis in vitro were evaluated using the CCK-8 assay and flow cytometry, respectively. An in vivo mouse model of colorectal cancer was used to determine the anti-tumor efficacy of the sAPRIL-BP.

Results

Three candidate peptides were characterized from eight phage clones with high binding affinity for sAPRIL. The peptide with the highest affinity was selected for further characterization. The identified sAPRIL-BP suppressed tumor cell proliferation and cell cycle progression in LOVO cells in a dose-dependent manner. In vivo in a mouse colorectal challenge model, the sAPRIL-BP reduced the growth of tumor xenografts in nude mice by inhibiting proliferation and inducing apoptosis intratumorally. Moreover, in an in vivo metastasis model, sAPRIL-BP reduced liver metastasis of colorectal cancer cells.

Conclusions

sAPRIL-BP significantly suppressed tumor growth in vitro and in vivo and might be a candidate for treating colorectal cancers that express high levels of APRIL.  相似文献   

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Isthmin (ISM) is a secreted 60-kDa protein that potently induces endothelial cell (EC) apoptosis. It suppresses tumor growth and angiogenesis in mice when stably overexpressed in cancer cells. Although αvβ5 integrin serves as a low-affinity receptor for ISM, the mechanism by which ISM mediates antiangiogenesis and apoptosis in ECs remain to be fully resolved. In this work, we report the identification of cell-surface glucose-regulated protein 78 kDa (GRP78) as a high-affinity receptor for ISM (Kd=8.6 nM). We demonstrated that ISM-GRP78 interaction triggers apoptosis not only in activated ECs but also in cancer cells expressing high level of cell-surface GRP78. Normal cells and benign tumor cells tend to express low level of cell-surface GRP78 and are resistant to ISM-induced apoptosis. Upon binding to GRP78, ISM is internalized into ECs through clathrin-dependent endocytosis that is essential for its proapoptotic activity. Once inside the cell, ISM co-targets with GRP78 to mitochondria where it interacts with ADP/ATP carriers on the inner membrane and blocks ATP transport from mitochondria to cytosol, thereby causing apoptosis. Hence, ISM is a novel proapoptotic ligand that targets cell-surface GRP78 to trigger apoptosis by inducing mitochondrial dysfunction. The restricted and high-level expression of cell-surface GRP78 on cancer cells and cancer ECs make them uniquely susceptible to ISM-targeted apoptosis. Indeed, systemic delivery of recombinant ISM potently suppressed subcutaneous 4T1 breast carcinoma and B16 melanoma growth in mice by eliciting apoptosis selectively in the cancer cells and cancer ECs. Together, this work reveals a novel ISM-GRP78 apoptosis pathway and demonstrates the potential of ISM as a cancer-specific and dual-targeting anticancer agent.  相似文献   

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Artemisinin is the first-line drugs for the treatment of malaria. In recent years, a large number of reports showed that artemisinin exhibit anti-tumor activity. In this study, we used C6 glioma cells and rat C6 brain-glioma model to study anti-tumor activity of artemisinin in vivo and in vitro. We found that artemisinin inhibited the proliferation in C6 cells and induced cell cycle arrest and a caspase-3-dependent cell apoptosis. It also inhibited the growth of C6 brain-glioma in vivo and enhanced living state of rat brain-glioma model. These results suggested that artemisinin had significant anti-tumor activities on C6 cells both in vitro and in vivo. Artemisinin might be exploited as a promising clinical anti-cancer drug in future.  相似文献   

12.
There is a large body of scientific evidence suggesting that 3,3′-Diindolylmethane (DIM), a compound derived from the digestion of indole-3-carbinol, which is abundant in cruciferous vegetables, harbors anti-tumor activity in vitro and in vivo. Accumulating evidence suggests that AMP-activated protein kinase (AMPK) plays an essential role in cellular energy homeostasis and tumor development and that targeting AMPK may be a promising therapeutic option for cancer treatment in the clinic. We previously reported that a formulated DIM (BR-DIM; hereafter referred as B-DIM) with higher bioavailability was able to induce apoptosis and inhibit cell growth, angiogenesis, and invasion of prostate cancer cells. However, the precise molecular mechanism(s) for the anti-cancer effects of B-DIM have not been fully elucidated. In the present study, we investigated whether AMP-activated protein kinase (AMPK) is a molecular target of B-DIM in human prostate cancer cells. Our results showed, for the first time, that B-DIM could activate the AMPK signaling pathway, associated with suppression of the mammalian target of rapamycin (mTOR), down-regulation of androgen receptor (AR) expression, and induction of apoptosis in both androgen-sensitive LNCaP and androgen-insensitive C4-2B prostate cancer cells. B-DIM also activates AMPK and down-regulates AR in androgen-independent C4-2B prostate tumor xenografts in SCID mice. These results suggest that B-DIM could be used as a potential anti-cancer agent in the clinic for prevention and/or treatment of prostate cancer regardless of androgen responsiveness, although functional AR may be required.  相似文献   

13.
Jasmonates act as signal transduction intermediates when plants are subjected to environmental stresses such as UV radiation, osmotic shock and heat. In the past few years several groups have reported that jasmonates exhibit anti-cancer activity in vitro and in vivo and induce growth inhibition in cancer cells, while leaving the non-transformed cells intact. Recently, jasmonates were also discovered to have cytotoxic effects towards metastatic melanoma both in vitro and in vivo.Three mechanisms of action have been proposed to explain this anti-cancer activity. The bio-energetic mechanism – jasmonates induce severe ATP depletion in cancer cells via mitochondrial perturbation. Furthermore, methyl jasmonate (MJ) has the ability to detach hexokinase from the mitochondria. Second, jasmonates induce re-differentiation in human myeloid leukemia cells via mitogen-activated protein kinase (MAPK) activity and were found to act similar to the cytokinin isopentenyladenine (IPA). Third, jasmonates induce apoptosis in lung carcinoma cells via the generation of hydrogen peroxide, and pro-apoptotic proteins of the Bcl-2 family.Combination of MJ with the glycolysis inhibitor 2-deoxy-d-glucose (2DG) and with four conventional chemotherapeutic drugs resulted in super-additive cytotoxic effects on several types of cancer cells. Finally, jasmonates have the ability to induce death in spite of drug-resistance conferred by either p53 mutation or P-glycoprotein (P-gp) over-expression.In summary, the jasmonates are anti-cancer agents that exhibit selective cytotoxicity towards cancer cells, and thus present hope for the development of cancer therapeutics.  相似文献   

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The endoplasmic reticulum (ER) is involved in Ca2+ signaling and protein folding. ER Ca2+ depletion and accumulation of unfolded proteins activate the molecular chaperone GRP78 (glucose-regulated protein 78) which in turn triggers the ER stress response (ERSR) pathway aimed to restore ER homeostasis. Failure to adapt to stress, however, results in apoptosis. We and others have shown that malignant cells are more susceptible to ERSR-induced apoptosis than their normal counterparts, implicating the ERSR as a potential target for cancer therapeutics. Predicated on these findings, we developed an assay that uses a GRP78 biosensor to identify small molecule activators of ERSR in glioma cells. We performed a quantitative high-throughput screen (qHTS) against a collection of ~425,000 compounds and a comprehensive panel of orthogonal secondary assays was formulated for stringent compound validation. We identified novel activators of ERSR, including a compound with a 2,9-diazaspiro[5.5]undecane core, which depletes intracellular Ca2+ stores and induces apoptosis-mediated cell death in several cancer cell lines, including patient-derived and 3D cultures of glioma cells. This study demonstrates that our screening platform enables the identification and profiling of ERSR inducers with cytotoxic activity and advocates for characterization of these compound in in vivo models.  相似文献   

16.
BackgroundDepressive symptoms are thought to promote cancer development and depressive remission has been reported to be effective for defeating cancer. The herbal formula Xiao-Chai-Hu-Tang (XCHT), that has an anti-depressive efficacy, has been widely utilized in China. However, its anti-cancer effect and underlying mechanisms remain unclear.PurposeThe present study aims to investigate the effects of XCHT on the depression-associated tumor and its potential mechanisms.MethodsA placebo-controlled trial was conducted in cancer patients comorbid with depressive symptoms to evaluate the effects of XCHT on depressive scales, tumor-related immune indicators, and gut microbial composition. A xenografted colorectal cancer (CRC) mouse model exposure to chronic restraint stress (CRS) was established to examine XCHT effects on tumorigenesis in vivo. Further, by manipulating gut bacteria with fecal microbial transplantation (FMT) or antibiotics-induced bacterial elimination in CRS-associated xenografted model, gut microbiota-mediated anti-tumor mechanism was explored.ResultsIn cancer patients comorbid with depressive symptoms, XCHT showed substantial effects on improvement of depressive scales, system inflammatory levels and gut dysbiosis. In vivo, XCHT inhibited tumor growth and prolonged survival time in addition to showing anti-depressive effect. Similarly, in our clinical trial, XCHT partially reversed gut dysbiosis, particularly through reducing abundances of Parabacteroides, Blautia and Ruminococcaceae bacterium. Manipulation of gut bacteria in CRS-associated xenografted model further proved that the inhibition of XCHT on tumor progression was mediated by gut microbiota and that the underlying mechanism involves in downregulation of TLR4/MyD88/NF-κB signaling.ConclusionsWe demonstrated that gut microbiota mediates the anti-tumor action of the formula XCHT in cancer patients and models that were comorbid with depressive symptoms. This study implies a novel clinical significance of anti-depressive herbal medicine in the cancer treatment and clarifies the important role of gut microbiota in treating cancer accompanied by depressive symptoms.  相似文献   

17.
Glucose-regulated protein 78 (GRP78), an important molecular chaperone in the endoplasmic reticulum, is often over-expressed in the central region of advanced tumor and acts as a promoter of tumor progression. As main immune cells in the tumor microenvironment, infiltration of abundant macrophages into advanced tumor further facilitates growth of tumor. Although has potential association between GRP78 and infiltration of macrophages, its underlying mechanisms are poorly understood. Here, we report that secreted GRP78 facilitates recruitment of macrophages into tumors both in vitro and in vivo. Further studies reveal that secreted GRP78 transports into macrophages and bound to intracellular Ca2+, which lead to uneven distribution of Ca2+ and subsequent polarization of macrophages. The polarization of macrophages activates expression of microRNA-200b-3p. By directly targeting RhoGDI, miR-200b-3p stimulates the activity of RhoGTPase and ultimately leads to the distribution of GTP-Rac1 and GTP-Cdc42 in front protrusion and GTP-RhoA in rear contraction, which further results in migration of macrophages in a certain direction. Our results reveal a novel function of GRP78 to promote the recruitment of macrophages to tumor and provide a potential therapeutic target for malignancies.  相似文献   

18.
Resistance to chemotherapy is a key factor in the inefficacy of various forms of treatments for cancer. In the present study, chemo-resistant proteins, including glucose-regulated protein 78 (GRP78)/clusterin (CLU) targeted 1,2-dioleoyloxy-3-trimethylammoniumpropane (DOTAP) liposomes, were developed as a delivery system for co-delivery of camptothecin (CPT) and GRP78 siRNA/CLU siRNA. Their drug/gene co-deliveries were quantitatively assessed in cancer stem cells (CSC) and MCF-7 cells. DOTAP-CPT/siRNA were prepared via electrostatic interaction on GRP78 siRNA or CLU siRNA. The size and ζ-potential of liposomes and lipoplexes were measured by dynamic light scattering techniques and electrophoretic light scattering spectrophotometry. The lipoplexes formation was tested by using gel electrophoresis. Immunofluorescence analysis showed that the expression level of CLU and GRP78 were significantly elevated in CSC compared to MCF-7 cells. Transfection and drug-delivery efficiency of DOTAP-CPT/siRNA were quantitatively compared with Lipofectamine 2000. Compared to free CPT, DOTAP-CPT-siCLU delivery in CSC and MCF-7 cells increased transfection efficiency and chemo-sensitivity by 4.1- and 5.9-fold, respectively. On the other hand, DOTAP-CPT-siGRP78 delivery increased transfection efficiency and chemo sensitivity by 4.4- and 6.2-fold in CSC and MCF-7 cells, respectively, compared to free CPT. It is significant that 3?±?1.2-fold increase in transfection efficiency was achieved by lipofectamine. Consequently, an increase in anti-cancer/gene silencing efficacy was quantitatively observed as an effect of DOTAP-CPT/siRNA treatment, which was relatively higher than lipofectamine treatment. Conclusively, our experimental data quantitatively demonstrate that using DOTAP-CPT-siRNA specifically targeting (CSCs) chemo-resistant protein in vitro offers substantial potential for synergistic anti-cancer therapy.  相似文献   

19.
The glucose-regulated protein 78 (GRP78) is a plasminogen (Pg) receptor on the cell surface. In this study, we demonstrate that GRP78 also binds the tissue-type plasminogen activator (t-PA), which results in a decrease in Km and an increase in the Vmax for both its amidolytic activity and activation of its substrate, Pg. This results in accelerated Pg activation when GRP78, t-PA, and Pg are bound together. The increase in t-PA activity is the result of a mechanism involving a t-PA lysine-dependent binding site in the GRP78 amino acid sequence 98LIGRTWNDPSVQQDIKFL115. We found that GRP78 is expressed on the surface of neuroblastoma SK-N-SH cells where it is co-localized with the voltage-dependent anion channel (VDAC), which is also a t-PA-binding protein in these cells. We demonstrate that both Pg and t-PA serve as a bridge between GRP78 and VDAC bringing them together to facilitate Pg activation. t-PA induces SK-N-SH cell proliferation via binding to GRP78 on the cell surface. Furthermore, Pg binding to the COOH-terminal region of GRP78 stimulates cell proliferation via its microplasminogen domain. This study confirms previous findings from our laboratory showing that GRP78 acts as a growth factor-like receptor and that its association with t-PA, Pg, and VDAC on the cell surface may be part of a system controlling cell growth.  相似文献   

20.
Cancer is the second leading cause of death worldwide. Edible medicinal mushrooms have been used in traditional medicine as regimes for cancer patients. Recently anti-cancer bioactive components from some mushrooms have been isolated and their anti-cancer effects have been tested. Pleurotus ferulae, a typical edible medicinal mushroom in Xinjiang China, has also been used to treat cancer patients in folk medicine. However, little studies have been reported on the anti-cancer components of Pleurotus ferulae. This study aims to extract bioactive components from Pleurotus ferulae and to investigate the anti-cancer effects of the extracts. We used ethanol to extract anti-cancer bioactive components enriched with terpenoids from Pleurotus ferulae. We tested the anti-tumour effects of ethanol extracts on the melanoma cell line B16F10, the human gastric cancer cell line BGC 823 and the immortalized human gastric epithelial mucosa cell line GES-1 in vitro and a murine melanoma model in vivo. Cell toxicity and cell proliferation were measured by MTT assays. Cell cycle progression, apoptosis, caspase 3 activity, mitochondrial membrane potential (MMP), migration and gene expression were studied in vitro. PFEC suppressed tumor cell growth, inhibited cell proliferation, arrested cells at G0/G1 phases and was not toxic to non-cancer cells. PFEC also induced cell apoptosis and necrosis, increased caspase 3 activity, reduced the MMP, prevented cell invasion and changed the expression of genes associated with apoptosis and the cell cycle. PFEC delayed tumor formation and reduced tumor growth in vivo. In conclusion, ethanol extracted components from Pleurotus ferulae exert anti-cancer effects through direct suppression of tumor cell growth and invasion, demonstrating its therapeutic potential in cancer treatment.  相似文献   

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