Cancer

Dual inhibition of the PI3K and MAPK pathways enhances nab-paclitaxel/gemcitabine chemotherapy response in preclinical models of pancreatic cancer Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Niranjan Awasthi, David Kronenberger, Alexis Stefaniak, Md Sazzad Hassan, Urs von Holzen, Margaret A. Schwarz, Roderich E. Schwarz Abstract Standard chemotherapy for pancreatic ductal adenocarcinoma (PDAC), nab-paclitaxel (NPT) plus gemcitabine (Gem), has led to an average survival of 8.5 months. Presently, no therapeutics exist that effectively target the KRAS oncogene, activated in 95% of PDACs, but alternative strategies focus on inhibition of downstream effectors of KRAS signaling. Through combined inhibition of PI3K and MAPK signaling with MK-2206 (MK) and trametinib (Tra), enhancement of NPT + Gem response was evaluated. Median animal survival was significantly improved by the NPT + Gem combination (67% increase). Addition of MK-2206 or trametinib further increased median survival: NPT + Gem + MK (86%), NPT + Gem + Tra (105%), and NPT + Gem + MK + Tra (129%). In cell line-derived xenografts, the net tumor growth (in mm3) compared to controls (878.5) was significantly reduced by NPT + Gem (191.2), NPT + Gem + MK (150.7), NPT + Gem + Tra (62.2) and NPT + Gem + MK + Tra (49.9) therapies. In patient-derived xenografts, the combination of MK-2206 and trametinib with chemotherapy had an additive response in reducing tumor growth. Effects of therapy on tumor cell proliferation and apoptosis corresponded with tumor growth inhibition. These findings suggest that the standard chemotherapy response of PDAC can be enhanced through dual targeting of PI3K and MAPK signaling, which could lead to improved PDAC therapy.

p53-dependent upregulation of miR-16-2 by sanguinarine induces cell cycle arrest and apoptosis in hepatocellular carcinoma Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Beilei Zhang, Xinan Wang, Jiacong Deng, Haifeng Zheng, Wei Liu, Si Chen, Jie Tian, Fu Wang Abstract MicroRNAs (miRNAs) were involved in cancer progression, and the targeting of miRNAs by natural agents has opened avenues for cancer treatment and drug development. miR-16 functions as a tumor suppressor and is frequently deleted or downregulated in various human cancers, including hepatocellular carcinoma (HCC). In the present study, we employed a miR-16-responsive luciferase reporter to screen candidate compounds that modulate miR-16 expression from a natural product library. One compound, sanguinarine (SG), was capable of activating miR-16 in HCC cells with wildtype or mutated p53 expression but not in p53-deleted HCC cells. Mechanistic investigations revealed that SG increased p53 occupancy on the miR-16-2 promoter and decreased the expression of miR-16 target genes, including Bcl-2 and cyclin D1. Moreover, SG significantly inhibited HCC cell proliferation in a p53-dependent manner by inducing cell cycle arrest and reactive oxygen species (ROS)-associated apoptosis. Silencing miR-16 by treatment with anti-miR16 miRNA inhibitors rescued the cell viability repression effect caused by SG. Importantly, SG dramatically suppressed tumor growth in an HCC xenograft model, with little cytotoxicity. Taken together, our results provide a preclinical proof-of-concept for SG as a potential strategy for HCC treatment based on the restoration of miR-16 tumor suppressor function.

Exosomal transfer of miR-501 confers doxorubicin resistance and tumorigenesis via targeting of BLID in gastric cancer Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Xu Liu, Ying Lu, Yunchao Xu, Sizhu Hou, Jinli Huang, Bo Wang, Jinyao Zhao, Shilin Xia, Shujun Fan, Xiaotang Yu, Yue Du, Li Hou, Zhiyue Li, Zijie Ding, Shuo An, Bo Huang, Lianhong Li, Jianwu Tang, Jingfang Ju, Hongwei Guan Abstract Exosomal transfer of oncogenic miRNAs can enhance recipient cell growth, metastasis and chemoresistance. Currently we found that microRNA-501-5p (miR-501) was overexpressed in doxorubicin-resistant gastric cancer (GC) SGC7901/ADR cell-secreted exosomes (ADR Exo) than that in SGC7901 cell-secreted exosomes (7901 Exo). ADR Exo was internalized by SGC7901, and a Cy3-miR-501 mimic was transferred from SGC7901/ADR to SGC7901 via exosomes. ADR Exo conferred doxorubicin resistance, proliferation, migration and invasion abilities to negative control miRNA inhibitor-expressing GC cells, whereas it inhibited apoptosis. MiR-501 knockdown or BH3-like motif-containing protein, cell death inducer (BLID) overexpression could reverse the effects of ADR Exo on recipient cells. SGC7901 cells cocultured with SGC7901/ADR prior to treatment with GW4869 or transfection of a miR-501 inhibitor were sensitive to doxorubicin and exhibited attenuated proliferation, migration and invasion and increased apoptosis. The intratumoral injection of ADR Exo into negative control miRNA inhibitor-expressing SGC7901 cells induced rapid subcutaneous tumor growth and resistance to doxorubicin compared to that of miR-501 knockdown or BLID-overexpressing cells. This effect is possibly achieved by exosomal miR-501-induced downregulation of BLID, subsequent inactivation of caspase-9/-3 and phosphorylation of Akt. Exosomal miR-501 might be a therapeutic target for GC.

MLKL attenuates colon inflammation and colitis-tumorigenesis via suppression of inflammatory responses Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Qun Zhao, XianJun Yu, Ming Li, YongBo Liu, YaMei Han, XiXi Zhang, Xiao Ming Li, XiaoXia Wu, Jun Qin, Jing Fang, Haibing Zhang Abstract The mixed lineage kinase domain-like protein (MLKL) has emerged as a critical mediator of necroptosis, which results in the release of cellular damage-associated molecular patterns (DAMPs). However, its physiological role in regulating inflammation is not fully understood. We herein showed that Mlkl−/− mice were highly susceptible to colitis and colitis-associated tumorigenesis (CAT), which was associated with massive leukocyte infiltration and increased inflammatory responses. Moreover, we used bone marrow transplantation to reveal that MLKL in inflammatory cells is crucial for its role on colitis. Intestinal mucosal tissue and polyps isolated from Mlkl−/− mice exhibited increased ERK activation and elevated expression of genes associated with inflammation and cancer. Mechanistically, enhanced inflammation in Mlkl−/− mice was due to MEK/ERK activation particularly in dendritic cells (DCs). Our results demonstrate the role of MLKL in maintaining intestinal homeostasis and protecting against colitis and tumorigenesis.

Interferon-inducible lncRNA IRF1-AS represses esophageal squamous cell carcinoma by promoting interferon response Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Jianbing Huang, Jiagen Li, Yuan Li, Zhiliang Lu, Yun Che, Shuangshuang Mao, Yuanyuan Lei, Ruochuan Zang, Sufei Zheng, Chengming Liu, Xinfeng Wang, Ning Li, Nan Sun, Jie He Abstract Interferons (IFNs) play crucial roles in the development and treatment of cancer. Long non-coding RNAs (lncRNAs) are emerging molecules involved in cancer progression. Here, we identified and characterized an IFN-inducible nuclear lncRNA IRF1-AS (Interferon Regulatory Factor 1 Antisense RNA) which was positively correlated with IRF1 expression. IFNs upregulate IRF1-AS via the JAK-STAT pathway. Knockdown and overexpression of IRF1-AS revealed that IRF1-AS inhibits oesophageal squamous cell carcinoma (ESCC) proliferation and promotes apoptosis in vitro and in vivo. Mechanistically, IRF1-AS activates IRF1 (Interferon Regulatory Factor 1) transcription through interacting with ILF3 (Interleukin Enhancer Binding Factor 3) and DHX9 (DExH-Box Helicase 9). In turn, IRF1 binds to the IRF1-AS promoter directly and activates IRF1-AS transcription. Global analysis of IRF1-AS–regulated genes indicated that IRF1-AS activates the IFN response in vitro and in vivo. IRF1 knockdown in IRF1-AS–overexpressing cells abolished the antiproliferative effect and activation of the IFN response. Furthermore, IRF1-AS was downregulated in ESCC tissues, and low expression correlated with poor prognosis. In conclusion, the interferon-inducible lncRNA IRF1-AS represses esophageal squamous cell carcinoma progression by promoting interferon response through a positive regulatory loop with IRF1.

Stress hormone-mediated acceleration of breast cancer metastasis is halted by inhibition of nitric oxide synthase Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Renée L. Flaherty, Haya Intabli, Marta Falcinelli, Giselda Bucca, Andrew Hesketh, Bhavik A. Patel, Marcus C. Allen, Colin P. Smith, Melanie S. Flint Abstract Stress hormones have been shown to be important mediators in driving malignant growth and reducing treatment efficacy in breast cancer. Glucocorticoids can induce DNA damage through an inducible nitric oxide synthase (iNOS) mediated pathway to increase levels of nitric oxide (NO). Using an immune competent mouse breast cancer model and 66CL4 breast cancer cells we identified a novel role of NOS inhibition to reduce stress-induced breast cancer metastasis. On a mechanistic level we show that the glucocorticoid cortisol induces expression of keys genes associated with angiogenesis, as well as pro-tumourigenic immunomodulation. Transcriptomics analysis confirmed that in the lungs of tumour-bearing mice, stress significantly enriched pathways associated with tumourigenesis, some of which could be regulated with NOS inhibition. These results demonstrate the detrimental involvement of NOS in stress hormone signalling, and the potential future benefits of NOS inhibition in highly stressed patients.

DEPTOR inhibits cell proliferation and confers sensitivity to dopamine agonist in pituitary adenoma Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Hong Yao, Hao Tang, Yong Zhang, Qiu Fen Zhang, Xin Yi Liu, Yan Ting Liu, Wei Ting Gu, Yong Zhi Zheng, Han Bing Shang, Yu Wang, Jin Yan Huang, Yong Xu Wei, Xun Zhang, Jian Zhang, Zhe Bao Wu Abstract DEP domain-containing mechanistic target of rapamycin (mTOR)-interacting protein (DEPTOR) is an important modulator of mTOR, a highly conserved kinase whose hyperactivation is critically involved in a variety of human tumors. The role of DEPTOR playing in pituitary adenoma (PA) is largely unknown. Here, we reported that DEPTOR was downregulated in PA tissues, especially dopamine-resistant prolactinomas. Consistently, overexpression of DEPTOR inhibited pituitary tumor GH3 and MMQ cells proliferation in vitro and in vivo, and sensitized GH3 and MMQ cells to cabergoline (CAB), a dopamine agonist (DA). Conversely, knockdown of DEPTOR promoted GH3 and MMQ cells proliferation, and conferred cells resistance to CAB. Mechanistically, DEPTOR inhibited both mTOR Complex 1 (mTORC1) and 2 (mTORC2) activities in PA cells. In addition, DEPTOR expression level was increased to suppress mTOR kinase activity via decreasing E3 ubiquitin ligase, βTrCP1, in response to CAB. Furthermore, DEPTOR enhanced autophagy-dependent cell death to confer cells sensitivity to CAB. Taken together, our results suggest that DEPTOR may be a potential target for the treatment of PAs.

Oncolytic Ad co-expressing decorin and Wnt decoy receptor overcomes chemoresistance of desmoplastic tumor through degradation of ECM and inhibition of EMT Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Yan Li, JinWoo Hong, Bo-Kyeong Jung, Eonju Oh, Chae-Ok Yun Abstract Pancreatic cancer is a highly lethal disease. Excessive accumulation of tumor extracellular matrix (ECM) and epithelial-to-mesenchymal transition (EMT) phenotype are two main contributors to drug resistance in desmoplastic pancreatic tumors. To overcome desmoplasia and chemoresistance of pancreatic cancer, we utilized an oncolytic adenovirus (Ad) co-expressing decorin and soluble Wnt decoy receptor (HEmT-DCN/sLRP6). An orthotopic pancreatic xenograft tumor model was established in athymic nude mice using Mia PaCa-2 cells, and the antimetastatic and antitumor efficacy of systemically administered HEmT-DCN/sLRP6 was evaluated. Immunohistochemical analysis of tumor tissues was performed to assess ECM degradation, induction of apoptosis, viral dispersion, and inhibition of the Wnt/β-catenin signaling pathway. HEmT-DCN/sLRP6 effectively degraded tumor ECM and inhibited EMT, leading to enhanced viral distribution, induction of apoptosis, and attenuation of tumor cell proliferation in tumor tissue. HEmT-DCN/sLRP6 prevented metastasis of pancreatic cancer. Importantly, HEmT-DCN/sLRP6 sensitized pancreatic tumor to gemcitabine treatment. Furthermore, HEmT-DCN/sLRP6 augmented drug penetration and dispersion within pancreatic tumor xenografts and patient-derived tumor spheroids. Collectively, these results illustrate that HEmT-DCN/sLRP6 can enhance the dispersion of both oncolytic Ad and a chemotherapeutic agent in chemoresistant and desmoplastic pancreatic tumor, effectively overcoming the preexisting limitations of standard treatments.

Patient-derived cell line models revealed therapeutic targets and molecular mechanisms underlying disease progression of high grade serous ovarian cancer Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Caroline Kreuzinger, Isabel von der Decken, Andrea Wolf, Magdalena Gamperl, Julia Koller, Jasmine Karacs, Stephanie Pfaffinger, Thomas Bartl, Alexander Reinthaller, Christoph Grimm, Christian F. Singer, Elena Ioana Braicu, Paula Cunnea, Charlie Gourley, Dominiek Smeets, Bram Boeckx, Diether Lambrechts, Paul Perco, Reinhard Horvat, Els M.J.J. Berns Abstract High grade serous ovarian cancer (HGSOC) is the most frequent type of ovarian cancer. Most patients have primary response to platinum-based chemotherapy but frequently relapse, which leads to patient death. A lack of well documented and characterized patient-derived HGSOC cell lines is so far a major barrier to define tumor specific therapeutic targets and to study the molecular mechanisms underlying disease progression. We established 34 patient-derived HGSOC cell lines and characterized them at cellular and molecular level. Particularly, we demonstrated that a cancer-testis antigen PRAME and Estrogen Receptor could serve as therapeutic targets. Notably, data from the cell lines did not demonstrate acquired resistance due to tumor recurrence that matched with clinical observations. Finally, we presented that all HGSOC had no or very low CDKN1A (p21) expression due to loss of wild-type TP53, suggesting that loss of cell cycle control is the determinant for tumorigenesis and progression. In conclusion, patient-derived cell lines reveal that PRAME is a potential tumor specific therapeutic target in HGSOC and counteracting the down-regulation of p21 caused by loss of wild-type TP53 might be the key to impede disease progression.

CFIm25 and alternative polyadenylation: Conflicting roles in cancer Publication date: 10 September 2019 Source: Cancer Letters, Volume 459 Author(s): Mohammad Hassan Jafari Najaf Abadi, Rana Shafabakhsh, Zatollah Asemi, Hamid Reza Mirzaei, Roxana Sahebnasagh, Hamed Mirzei, Michael R. Hamblin Abstract Alternative polyadenylation (APA) is now widely recognized to regulate gene expression. APA is an RNA-processing mechanism that generates distinct 3′ termini on mRNAs, producing mRNA isoforms. Different factors influence the initiation and development of this process. CFIm25 (among others) is a cleavage and polyadenylation factor that plays a key role in the regulation of APA. Shortening of the 3′UTRs on mRNAs leads to enhanced cellular proliferation and tumorigenicity. One reason may be the up-regulation of growth promoting factors, such as Cyclin D1. Different studies have reported a dual role of CFIm25 in cancer (both oncogenic and tumor suppressor). microRNAs (miRNAs) may be involved in CFIm25 function as well as competing endogenous RNAs (ceRNAs). The present review focuses on the role of CFIm25 in cancer, cancer treatment, and possible involvement in other human diseases. We highlight the involvement of miRNAs and ceRNAs in the function of CFIm25 to affect gene expression. The lack of understanding of the mechanisms and regulation of CFIm25 and APA has underscored the need for further research regarding their role in cancer and other diseases.

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com