sepantronium and Pancreatic-Neoplasms

Mutations in KRAS frequently occur in human cancer and are especially prevalent in pancreatic ductal adenocarcinoma (PDAC), where they have been shown to promote aggressive phenotypes. However, targeting this onco-protein has proven to be challenging, highlighting the need to further identify the various mechanisms used by KRAS to drive cancer progression. Here, we considered the role played by exosomes, a specific class of extracellular vesicles (EVs) derived from the endocytic cellular trafficking machinery, in mediating the ability of KRAS to promote cell survival. We found that exosomes isolated from the serum of PDAC patients, as well as from KRAS-transformed fibroblasts and pancreatic cancer cells, were all highly enriched in the cell survival protein Survivin. Exosomes containing Survivin, upon engaging serum-starved cells, strongly enhanced their survival. Moreover, they significantly compromised the effectiveness of the conventional chemotherapy drug paclitaxel, as well as a novel therapy that combines an ERK inhibitor with chloroquine, which is currently in clinical trials for PDAC. The survival benefits provided by oncogenic KRAS-derived exosomes were markedly reduced when depleted of Survivin using siRNA or upon treatment with the Survivin inhibitor YM155. Taken together, these findings demonstrate how KRAS mutations give rise to exosomes that provide a unique form of intercellular communication to promote cancer cell survival and therapy resistance, as well as raise interesting possibilities regarding their potential for serving as therapeutic targets and diagnostic markers for KRAS-dependent cancers.

Topics: Cell Communication; Cell Line, Tumor; Cell Survival; Chloroquine; Exosomes; Extracellular Vesicles; Fibroblasts; Humans; Imidazoles; Mutation; Naphthoquinones; Paclitaxel; Pancreas; Pancreatic Neoplasms; Proto-Oncogene Proteins p21(ras); Survivin

Treating pancreatic ductal adenocarcinoma (PDAC) remains a major hurdle in the field of oncology. Less than half of patients respond to frontline chemotherapy and the pancreatic tumor microenvironment limits the efficacy of immunotherapeutic approaches. Targeted therapies could serve as effective treatments to enhance the clinical response rate. One potential therapeutic target is survivin, a protein that is normally expressed during embryonic and fetal development and has a critical impact on cell cycle control and apoptosis. In adulthood, survivin is not present in most normal adult cells, but is significantly re-expressed in tumor tissues. In PDAC, elevated survivin expression is correlated with treatment resistance and lower patient survival, although the underlying mechanisms of survivin's action in this type of cancer is poorly understood. Using patient derived xenografts of PDAC and their corresponding primary pancreatic cancer lines (PPCL-46 and PPCL-LM1) possessing increased expression of survivin, we aimed to evaluate the therapeutic response of a novel survivin inhibitor, UFSHR, with respect to survivin expression and the tumorigenic characteristics of PDAC. Cell viability and apoptosis analyses revealed that repressing survivin expression by UFSHR or YM155, a well-known inhibitor of survivin, in PPCLs effectively reduces cell proliferation by inducing apoptosis. Tumor cell migration was also hindered following treatment with YM155 and UFSHR. In addition, both survivin inhibitors, particularly UFSHR, effectively reduced progression of PPCL-46 and PPCL-LM1 tumors, when compared to the untreated cohort. Overall, this study provides solid evidence to support the critical role of survivin in PDAC progression and proposes a novel survivin inhibitor UFSHR that can become an alternative strategy for this type of cancer.

Topics: Animals; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Proliferation; Cell Survival; Disease Progression; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Mice; Naphthoquinones; Pancreatic Neoplasms; Precision Medicine; Survivin; Transplantation, Heterologous; Up-Regulation

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) represent a rare and heterogenous tumor entity. Importantly, the highly proliferative subgroup of neuroendocrine carcinoma (GEP-NEC) is characterized by high resistance to conventional chemotherapy. Consequently, there is an urgent need to identify novel therapeutic targets, especially for GEP-NEC. Thus, we focused on Inhibitor of apoptosis protein (IAP) family members survivin and XIAP that orchestrate inhibition of apoptosis, induce resistance against chemotherapeutics and facilitate tumor metastasis. Copy number gains (CNGs) could be detected by microarray comparative genomic hybridization for survivin and XIAP in 60 % and 26.7 % of all GEP-NENs, respectively. Immunohistochemical staining of tissue specimens from 77 consecutive patients with GEP-NEN demonstrated increased survivin protein expression levels in tissue specimens of highly proliferative GEP-NEC or GEP-NEN located in the stomach and colon. In contrast, XIAP overexpression was associated with advanced tumor stages. Knockdown of survivin and XIAP markedly reduced cell proliferation and tumor growth. In vitro, YM155 induced apoptotic cell death accompanied by a reduction in cell proliferation and inhibited GEP-NEC xenograft growth. Taken together, our data provide evidence for a biological relevance of these IAPs in GEP-NEN and support a potential role of survivin as therapeutic target especially in the subgroup of aggressive GEP-NEC.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biomarkers, Tumor; Carcinoma, Neuroendocrine; Cell Line, Tumor; Cell Proliferation; Comparative Genomic Hybridization; DNA Copy Number Variations; Dose-Response Relationship, Drug; Female; Gene Dosage; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Immunohistochemistry; Inhibitor of Apoptosis Proteins; Intestinal Neoplasms; Male; Masoprocol; Mice, Inbred NOD; Mice, SCID; Molecular Targeted Therapy; Naphthoquinones; Oligonucleotide Array Sequence Analysis; Pancreatic Neoplasms; Retrospective Studies; RNA Interference; Signal Transduction; Stomach Neoplasms; Survivin; Time Factors; Transfection; Tumor Burden; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays

Despite much effort, pancreatic cancer survival rates are still dismally low. Novel therapeutics may hold the key to improving survival. YM155 is a small molecule inhibitor that has shown antitumor activity in a number of cancers by reducing the expression of survivin. The aim of our study is to understand the mechanisms by which YM155 functions in pancreatic cancer cells. We established the antitumor effect of YM155 with in vitro studies in cultured cells, and in vivo studies using a mouse xenograft model. Our data demonstrated that YM155 reduced the expression of survivin; however, downregulation of survivin itself is insufficient to induce apoptosis in pancreatic cancer cells. We showed for the first time that treatment with YM155 increased death receptor 5 (DR5) expression in pancreatic cancer cells. We found that YM155 induced apoptosis by broad-spectrum inhibition of IAP family member proteins (e.g., CIAP1/2 and FLIP) and induced proapoptotic Bak protein upregulation and activation; the antitumor effect of YM155 treatment with either the DR5 agonist lexatumumab or gemcitabine on pancreatic cancer cells was synergistic. Our data also revealed that YM155 inhibits tumor growth in vivo, without apparent toxicity to the noncancerous human pancreatic ductal epithelial cell line. Together, these findings suggest that YM155 could be a novel therapeutic agent for pancreatic cancer.

Topics: Animals; Antibodies, Monoclonal; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Drug Synergism; Gemcitabine; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Mice; Mice, SCID; Naphthoquinones; Pancreatic Neoplasms; Receptors, TNF-Related Apoptosis-Inducing Ligand; Survivin; Xenograft Model Antitumor Assays

Survivin is a negative regulator of apoptosis. We evaluated the efficacy of YM155, a selective suppressant of survivin, in combination with gemcitabine in the pancreatic cancer cell line MiaPaCa-2.. Expression of survivin was demonstrated by immunoblotting. Cell cycle progression was determined by flow cytometric analysis. Cell viability was assayed using the trypan blue exclusion assay.. Gemcitabine up-regulated survivin expression, whereas treatment with YM155 suppressed the expression of survivin. Concomitant treatment with YM155 enhanced chemosensitivity to gemcitabine, which was accompanied by a decrease in the expression of survivin. Knockdown of endogenous survivin via RNA interference also enhanced the sensitivity to gemcitabine. In addition, YM155 potentiated the antitumor effect of gemcitabine in xenograft tumors of MiaPaCa-2.. YM155 potentiates chemosensitivity to gemcitabine in pancreatic cancer cells by suppressing the induction of survivin. Combination treatment with gemcitabine and YM155 may be a potential therapeutic strategy for the treatment of pancreatic cancer that warrants further clinical investigation.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Deoxycytidine; Drug Resistance, Neoplasm; Drug Synergism; Female; Gemcitabine; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Mice; Mice, Inbred BALB C; Naphthoquinones; Pancreatic Neoplasms; RNA, Small Interfering; Survivin

YM155, which inhibits the anti-apoptotic protein survivin, is known to exert anti-tumor effects in various cancers, including prostate and lung cancer. However, there are few reports describing the inhibitory effect of YM155 on human pancreatic cancers that highly express survivin. Here, we tested the effects of YM155 on a variety of cancer cell lines, including pancreatic cancer cells. We found that YM155 exerts an anti-proliferative effect in pancreatic cancer cells, inducing cell death through suppression of XIAP (X-linked inhibitor of apoptosis) as well as survivin without affecting the anti-apoptotic proteins Bcl-xL or Mcl-1. YM155 also inhibited tumor growth in vivo, reducing the size of pancreatic cancer cell line MIAPaCa-2 xenografts by 77.1% on day 31. Western blot analyses further showed that YM155 downregulated phosphoinoside 3-kinase (PI3K) expression and reduced the levels of phosphorylated (activated) extracellular signal-regulated kinase (ERK) and STAT3 (signal transducer and activator of transcription 3) in PANC-1 cells. Interestingly, we also found that YM155 downregulated the epidermal growth factor receptor (EGFR) in various cancer cell lines and induced the EGFR phosphorylation and ubiquitination of EGFR in PANC-1 cells. YM155 also modestly promoted the ubiquitination of survivin and XIAP. Therefore, YM155 acts through modulation of EGFR and survivin expression to subsequently reduce survival. We suggest that YM155 has potential as a therapeutic agent in the treatment of pancreatic cancer.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; ErbB Receptors; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression Regulation, Neoplastic; Humans; Imidazoles; Inhibitor of Apoptosis Proteins; Inhibitory Concentration 50; Mice; Mice, Nude; Naphthoquinones; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphorylation; Promoter Regions, Genetic; Proteolysis; STAT3 Transcription Factor; Survivin; Tumor Burden; Ubiquitination; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays