Nardilysin-regulated scission mechanism activates polo-like kinase 3 to suppress the development of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) develops through step-wise genetic and molecular alterations including Kras mutation and inactivation of various apoptotic pathways. Here, we find that development of apoptotic resistance and metastasis of KrasG12D-driven PDAC in mice is accelerated by deleting Plk3, explaining the often-reduced Plk3 expression in human PDAC. Importantly, a 41-kDa Plk3 (p41Plk3) that contains the entire kinase domain at the N-terminus (1-353 aa) is activated by scission of the precursor p72Plk3 at Arg354 by metalloendopeptidase nardilysin (NRDC), and the resulting p32Plk3 C-terminal Polo-box domain (PBD) is removed by proteasome degradation, preventing the inhibition of p41Plk3 by PBD. We find that p41Plk3 is the activated form of Plk3 that regulates a feed-forward mechanism to promote apoptosis and suppress PDAC and metastasis. p41Plk3 phosphorylates c-Fos on Thr164, which in turn induces expression of Plk3 and pro-apoptotic genes. These findings uncover an NRDC-regulated post-translational mechanism that activates Plk3, establishing a prototypic regulation by scission mechanism.

Tumor-associated nonmyelinating Schwann cell-expressed PVT1 promotes pancreatic cancer kynurenine pathway and tumor immune exclusion.

One of the major obstacles to treating pancreatic ductal adenocarcinoma (PDAC) is its immunoresistant microenvironment. The functional importance and molecular mechanisms of Schwann cells in PDAC remains largely elusive. We characterized the gene signature of tumor-associated nonmyelinating Schwann cells (TASc) in PDAC and indicated that the abundance of TASc was correlated with immune suppressive tumor microenvironment and the unfavorable outcome of patients with PDAC. Depletion of pancreatic-specific TASc promoted the tumorigenesis of PDAC tumors. TASc-expressed long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) was triggered by the tumor cell-produced interleukin-6. Mechanistically, PVT1 modulated RAF proto-oncogene serine/threonine protein kinase-mediated phosphorylation of tryptophan 2,3-dioxygenase in TASc, facilitating its enzymatic activities in catalysis of tryptophan to kynurenine. Depletion of TASc-expressed PVT1 suppressed PDAC tumor growth. Furthermore, depletion of TASc using a small-molecule inhibitor effectively sensitized PDAC to immunotherapy, signifying the important roles of TASc in PDAC immune resistance.

Recombinant Thrombomodulin Has Anti-tumor Effects and Enhances the Effects of Gemcitabine for Pancreatic Cancer Through G-protein Coupled Receptor 15.

BACKGROUND/AIM: Thrombomodulin™ has cytoprotective and anti-inflammatory function by interacting with G-protein coupled receptor 15 (GPR15). Recombinant TM (rTM), which comprises the extracellular regions of TM, is approved for treatment of disseminated intravascular coagulation. We investigated the anti-tumor effect of rTM for pancreatic ductal adenocarcinoma (PDAC) through GPR15. MATERIALS AND METHODS: We evaluated the expression of GPR15 in human PDAC cell lines and the anti-tumor effect and signals of rTM in vitro and in vivo. To test whether GPR15 would be responsible for the inhibition of cell proliferation by rTM, we evaluated the cell viability of the GPR15 knockdown cells treated with rTM using GPR15-targeting siRNA. RESULTS: We identified PDAC cell lines with GPR15 expression and discovered that rTM inhibited tumor growth and enhanced the effects of gemcitabine (GEM) for the PDAC cell line in a GPR15-dependent manner. Furthermore, we showed that rTM inhibited nuclear factor-kappaB (NF-[Formula: see text]B) and extracellular signal-regulated kinase (ERK) activation through interactions with GPR15. CONCLUSION: We demonstrated that rTM had anti-tumor effect and enhancement of cytotoxic effect of GEM for PDAC cells by inhibiting NF-[Formula: see text]B and ERK activation via GPR15 and suggest that rTM is a potential therapeutic option for PDAC.

3D imaging analysis on an organoid-based platform guides personalized treatment in pancreatic ductal adenocarcinoma.

BACKGROUNDPancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, with unpredictable responses to chemotherapy. Approaches to assay patient tumors before treatment and identify effective treatment regimens based on tumor sensitivities are lacking. We developed an organoid-based platform (OBP) to visually quantify patient-derived organoid (PDO) responses to drug treatments and associated tumor-stroma modulation for personalized PDAC therapy.METHODSWe retrospectively quantified apoptotic responses and tumor-stroma cell proportions in PDOs via 3D immunofluorescence imaging through annexin A5, α-smooth muscle actin (α-SMA), and cytokeratin 19 (CK-19) levels. Simultaneously, an ex vivo organoid drug sensitivity assay (ODSA) was used to measure responses to standard-of-care regimens. Differences between ODSA results and patient tumor responses were assessed by exact McNemar's test.RESULTSImmunofluorescence signals, organoid growth curves, and Ki-67 levels were measured and authenticated through the OBP for up to 14 days. ODSA drug responses were not different from patient tumor responses, as reflected by CA19-9 reductions following neoadjuvant chemotherapy (P = 0.99). PDOs demonstrated unique apoptotic and tumor-stroma modulation profiles (P < 0.0001). α-SMA/CK-19 ratio levels of more than 1.0 were associated with improved outcomes (P = 0.0179) and longer parental patient survival by Kaplan-Meier analysis (P = 0.0046).CONCLUSIONHeterogenous apoptotic drug responses and tumor-stroma modulation are present in PDOs after standard-of-care chemotherapy. Ratios of α-SMA and CK-19 levels in PDOs are associated with patient survival, and the OBP could aid in the selection of personalized therapies to improve the efficacy of systemic therapy in patients with PDAC.FUNDINGNIH/National Cancer Institute grants (K08CA218690, P01 CA117969, R50 CA243707-01A1, U54CA224065), the Skip Viragh Foundation, the Bettie Willerson Driver Cancer Research Fund, and a Cancer Center Support Grant for the Flow Cytometry and Cellular Imaging Core Facility (P30CA16672).

Cisplatin and gemcitabine exert opposite effects on immunotherapy with PD-1 antibody in K-ras-driven cancer.

INTRODUCTION: Immunochemotherapy using PD-1/PD-L1 antibodies in combination with chemotherapeutic agents has become a mainstream treatment for cancer patients, but it remains unclear which drug combinations would produce best therapeutic outcome. OBJECTIVES: The purpose of this study was to investigate two common chemotherapeutic drugs, gemcitabine and cisplatin, for their impacts on the therapeutic efficacy of PD-1 antibody in K-ras-driven cancers known to overexpress PD-L1. METHODS: Both in vitro assays and syngeneic mouse tumor models were used in this study. Biochemical and molecular assays were used to determine the effects of drugs on T cell functions in cell culture models and in mouse/human tumor tissues. Allograft tumor models with K-ras mutation were used to investigate the combination effect of gemcitabine or cisplatin with immunotherapy. Data of lung cancer patients with K-ras mutation treated with cisplatin and toripalimab were analyzed to evaluate the clinical relevance of the lab findings. RESULTS: Cisplatin and gemcitabine unexpectedly exert opposite effect on the therapeutic activity of PD-1 antibody in vivo. Gemcitabine antagonizes the therapeutic effect of PD-1 antibody due to its significant inhibition on CD8+ T cell infiltration, which was observed both in mouse tumor allografts and in human pancreatic cancer tissues. In contrast, cisplatin shows synergistic activity with PD-1 antibody by activation of CD8+ T cells through the DNA damage-mediated cGAS-STING sensing mechanism, leading to increase of T cell infiltration and secretion of antitumor cytokines. Clinical data show that a combination of cisplatin with PD-1 antibody toripalimab could be effective in advanced lung cancer patients with K-ras mutation who failed prior therapies. CONCLUSIONS: Our study shows that a key factor in selecting chemotherapeutic agents for immunochemotherapy is the drug's impact on T cell functions, and that cisplatin-based chemotherapy is an excellent choice for combination with immune checkpoint antibody to achieve favorable clinical outcome.

ATF4/TXNIP/REDD1/mTOR signaling mediates the antitumor activities of liver X receptor in pancreatic cancers.

Background: Limited by difficulties in early detection and availabilities of effective treatments, pancreatic cancer is a highly malignant disease with poor prognosis. Nuclear receptors are a family of ligand-dependent transcription factors that are highly druggable therapeutic targets playing critical roles in human physiological and pathological development, including cancer. In this study, we explored the therapeutic potential as well as the molecular mechanisms of liver X receptor (LXR) agonist GW3965 in pancreatic cancer. Methods: Soft-agar colony formation assay, xenograft tumors, Oligonucleotide microarray, Reverse transcription real-time polymerase chain reaction, Western immunoblotting and Immunohistochemistry were used in this study. Results: We demonstrated pleotropic in vitro activities of GW3965 in pancreatic cell lines MIA PaCa-2 and BXPC3 including reduction of cell viability, inhibition of cell proliferation, stimulation of cell death, and suppression of colony formation, which translated to significant inhibition of xenograft tumor growth in vitro. By mapping the gene expression profiles, we identified the up-regulations of 188 and the down-regulations of 92 genes common to both cell lines following GW3965 treatment. Genes responsive to GW3965 represent a variety of biological pathways vital for multiple cellular functions. Specifically, we identified that the activating transcription factor 4/thioredoxin-interacting protein/regulated in development and DNA damage responses 1/mechanistic target of rapamycin (ATF4/TXNIP/REDD1/mTOR) signaling critically controls GW3965-mediated regulation of cell proliferation/death. The significance of the ATF4/TXNIP/REDD1/mTOR pathway was further supported by associated expressions in xenograft tumors as well as human pancreatic cancer samples. Conclusions: This study provides the pre-clinical evidence that LXR agonist is a promising therapy for pancreatic cancer.

CES2 sustains HNF4α expression to promote pancreatic adenocarcinoma progression through an epoxide hydrolase-dependent regulatory loop.

OBJECTIVE: Intra-tumoral expression of the serine hydrolase carboxylesterase 2 (CES2) contributes to the activation of the pro-drug irinotecan in pancreatic ductal adenocarcinoma (PDAC). Given other potential roles of CES2, we assessed its regulation, downstream effects, and contribution to tumor development in PDAC. METHODS: Association between the mRNA expression of CES2 in pancreatic tumors and overall survival was assessed using The Cancer Genome Atlas. Cell viability, clonogenic, and anchorage-independent growth assays as well as an orthotopic mouse model of PDAC were used to evaluate the biological relevance of CES2 in pancreatic cancer. CES2-driven metabolic changes were determined by untargeted and targeted metabolomic analyses. RESULTS: Elevated tumoral CES2 mRNA expression was a statistically significant predictor of poor overall survival in PDAC patients. Knockdown of CES2 in PDAC cells reduced cell viability, clonogenic capacity, and anchorage-independent growth in vitro and attenuated tumor growth in an orthotopic mouse model of PDAC. Mechanistically, CES2 was found to promote the catabolism of phospholipids resulting in HNF4α activation through a soluble epoxide hydrolase (sEH)-dependent pathway. Targeting of CES2 via siRNA or small molecule inhibitors attenuated HNF4α protein expression and reduced gene expression of classical/progenitor markers and increased basal-like markers. Targeting of the CES2-sEH-HNF4α axis using small molecule inhibitors of CES2 or sEH reduced cell viability. CONCLUSIONS: We establish a novel regulatory loop between CES2 and HNF4α to sustain the progenitor subtype and promote PDAC progression and highlight the potential utility of CES2 or sEH inhibitors for the treatment of PDAC as part of non-irinotecan-containing regimens.

Circular RNAs regulate cancer-related signaling pathways and serve as potential diagnostic biomarkers for human cancers.

Circular RNAs (circRNAs) are RNAs that have an important role in various pathological processes, including cancer. After the usage of high-throughput RNA sequencing, many circRNAs were found to be differentially expressed in various cancer cell lines and regulate cell signaling pathways by modulating particular gene expressions. Understanding their role in these pathways and what cancers they are found in can set the stage for identifying diagnostic and prognostic biomarkers and therapeutic targets of cancer. This paper will discuss which circRNAs are found in different cancers and what mechanisms they use to upregulate or downregulate certain cellular components.

Regulation of PD-L1 expression in K-ras-driven cancers through ROS-mediated FGFR1 signaling.

K-ras mutations are major genetic events that drive cancer development associated with aggressive malignant phenotypes, while expression of the immune checkpoint molecule PD-L1 plays a key role in cancer evasion of the immune surveillance that also profoundly affects the patient outcome. However, the relationship between K-ras oncogenic signal and PD-L1 expressions as an important area that requires further investigation. Using both in vitro and in vivo experimental models of K-ras-driven cancer, we found that oncogenic K-ras significantly enhanced PD-L1 expression through a redox-mediated mechanism. Activation of K-rasG12V promoted ROS generation and induced FGFR1 expression, leading to a significant upregulation of PD-L1. We further showed that exogenous ROS such as hydrogen peroxide alone was sufficient to activate FGFR1 and induce PD-L1, while antioxidants could largely abrogate PD-L1 expression in K-ras mutant cells, indicating a critical role of redox regulation. Importantly, genetic knockout of FGFR1 led to a decrease in PD-L1 expression, and impaired tumor growth in vivo due to a significant increase of T cell infiltration in the tumor tissues and thus enhanced T-cell-mediated tumor suppression. Our study has identified a novel mechanism by which K-ras promotes PD-L1 expression, and suggests that modulation of ROS or inhibition of the FGFR1 pathway could be a novel strategy to abrogate PD-L1-mediated immunosuppression and thus potentially improve the efficacy of immunotherapy in K-ras-driven cancers.

The overexpression of long intergenic ncRNA00162 induced by RelA/p65 promotes growth of pancreatic ductal adenocarcinoma.

OBJECTIVES: Recent observations have emphasized the role of long non-coding RNA (lncRNA) in cancer progression; however, a genetic profile of lncRNAs in pancreatic ductal adenocarcinoma (PDAC) remains an ongoing study. MATERIALS AND METHODS: In this research, RNA sequencing showed that LINC00162 is dramatically increased in patient-derived tumour cell lines (PATC) compared with the human pancreatic nestin-positive epithelial (HPNE) cells. RESULTS: These data were validated in several PDAC cell lines, and significant upregulation of LINC00162 was found in all of them. Knock-down of LINC00162 significantly inhibited the proliferation, colony formation and migration of PATC cells in vitro and suppressed the growth of PATC xenografts in vivo. Overexpression of LINC00162 in PDAC cell lines (AsPc-1) showed consistent results, with significantly increased proliferation, colony formation and migration of AsPc-1 cells, as well as enhanced tumour growth of the AsPc-1 xenografts in vivo. Furthermore, the result of Chromatin immunoprecipitation assay revealed that RelA/p65 directly bound to LINC00162, and the expression of LINC00162 in PDAC decreased after RelA/p65 knock-down, the proliferation ability of AsPc-1 also significantly inhibited after knocking down LINC00162 and RelA/p65 simultaneously, indicating that RelA/p65 directly involve in the transcriptional regulation of LINC00162. CONCLUSIONS: In sum, our results provide first evidence for the role of LINC00162 in promoting PDAC progression and the potential underlying mechanism of LINC00162 overexpression.

Circulating levels of hydroxylated bradykinin function as an indicator of tissue HIF-1α expression.

The critical roles of oxygen homeostasis in metabolism are indisputable and hypoxic responses are correlated with the pathogenesis of gastrointestinal, pulmonary, renal diseases and cancers. Evaluating tissue hypoxia to predict treatment outcome is challenging, however, due to the lack of rapid, accurate and non-invasive methods. Hypoxia enhances prolyl-4-hydroxylase α1 (P4HA1) expression, which can convert bradykinin (BK) to hydroxyprolyl-BK (Hyp-BK), leading us to hypothesize that circulating Hyp-BK/BK ratios may reflect tissue hypoxia and predict treatment outcomes. Direct quantification of Hyp-BK peptides in serum or plasma by conventional MALDI-TOF MS analysis is technically challenging. In our study, a nanopore-based fractionation and enrichment protocol was utilized to allow the simple workflow for circulating Hyp-BK/BK analysis. Hypoxia is linked to poor prognosis due to its role in promoting pancreatic cancer progression and metastasis. Here we show that P4HA1 expression was increased in pancreatic tumors versus adjacent tissue, associated with poor survival, and corresponded with tumor expression of the hypoxia inducible factor 1α (HIF-1α) and carbonic anhydrase 9 (CA9). Hypoxia-induced P4HA1 expression and BK conversion to Hyp-BK were found to be HIF-1α dependent, pre-treatment serum Hyp-BK/BK ratios corresponded with tissue HIF-1α and P4HA1 expression, and high Hyp-BK/BK levels corresponded with poor response to therapy. These results suggest that pre-treatment circulating Hyp-BK/BK ratios may have value as a non-invasive, surrogate indicator of tissue hypoxia and tumor responses to therapy.

CES2 Expression in Pancreatic Adenocarcinoma Is Predictive of Response to Irinotecan and Is Associated With Type 2 Diabetes.

PURPOSE: The combination chemotherapy of fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) has provided clinically meaningful improvement for pancreatic ductal adenocarcinoma (PDAC). We previously uncovered a role for the serine hydrolase carboxylesterase 2 (CES2) in mediating intratumoral activation of the prodrug irinotecan, a constituent of FOLFIRINOX. We aimed to further test the predictive value of CES2 for response to irinotecan using patient-derived xenograft (PDX) models and to elucidate the determinants of CES2 expression and response to FOLFIRINOX treatment among patients with PDAC. METHODS: PDXs were engrafted subcutaneously into nude mice and treated for 4 weeks with either saline control or irinotecan. CES2 and hepatocyte nuclear factor 4 alpha (HNF4A) expression in PDAC tissues was evaluated by immunohistochemical and Western blot analysis. Kaplan-Meier and Cox regression analyses were applied to assess the association between overall survival and hemoglobin A1C (HbA1C) levels in patients who underwent neoadjuvant FOLFIRINOX treatment. RESULTS: High CES2 activity in PDAC PDXs was associated with increased sensitivity to irinotecan. Integrated gene expression, proteomic analyses, and in vitro genetic experiments revealed that nuclear receptor HNF4A, which is upregulated in diabetes, is the upstream transcriptional regulator of CES2 expression. Elevated CES2 protein expression in PDAC tissues was positively associated with a history of type 2 diabetes (odds ratio, 4.84; P = .02). High HbA1C levels were associated with longer overall survival in patients who received neoadjuvant FOLFIRINOX treatment (P = .04). CONCLUSION: To our knowledge, we provide, for the first time, evidence that CES2 expression is associated with a history of type 2 diabetes in PDAC and that elevated HbA1C, by predicting tumor CES2 expression, may represent a novel marker for stratifying patients most likely to respond to FOLFIRINOX therapy.

Suppression of the SLC7A11/glutathione axis causes synthetic lethality in KRAS-mutant lung adenocarcinoma.

Oncogenic KRAS is a major driver in lung adenocarcinoma (LUAD) that has yet to be therapeutically conquered. Here we report that the SLC7A11/glutathione axis displays metabolic synthetic lethality with oncogenic KRAS. Through metabolomics approaches, we found that mutationally activated KRAS strikingly increased intracellular cystine levels and glutathione biosynthesis. SLC7A11, a cystine/glutamate antiporter conferring specificity for cystine uptake, was overexpressed in patients with KRAS-mutant LUAD and showed positive association with tumor progression. Furthermore, SLC7A11 inhibition by either genetic depletion or pharmacological inhibition with sulfasalazine resulted in selective killing across a panel of KRAS-mutant cancer cells in vitro and tumor growth inhibition in vivo, suggesting the functionality and specificity of SLC7A11 as a therapeutic target. Importantly, we further identified a potent SLC7A11 inhibitor, HG106, that markedly decreased cystine uptake and intracellular glutathione biosynthesis. Furthermore, HG106 exhibited selective cytotoxicity toward KRAS-mutant cells by increasing oxidative stress- and ER stress-mediated cell apoptosis. Of note, treatment of KRAS-mutant LUAD with HG106 in several preclinical lung cancer mouse models led to marked tumor suppression and prolonged survival. Overall, our findings reveal that KRAS-mutant LUAD cells are vulnerable to SLC7A11 inhibition, offering potential therapeutic approaches for this currently incurable disease.

Two Birds with One Stone: Therapeutic Targeting of IL1α Signaling Pathways in Pancreatic Ductal Adenocarcinoma and the Cancer-Associated Fibroblasts.

In this issue of Cancer Discovery, Biffi and colleagues report that IL1 signaling cascades resulted in JAK/STAT activation and promoted an inflammatory cancer-associated fibroblast (iCAF) state, which contributed to the establishment of distinct fibroblast niches in the pancreatic ductal adenocarcinoma (PDAC) microenvironment to support the growth of PDAC cells. Furthermore, the investigators demonstrated that TGFß signaling inhibited IL1R1 expression, antagonized IL1α responses, and promoted differentiation of CAFs into myofibroblasts; thus, IL1α signaling is an important therapeutic target for both PDAC cells and the iCAFs in the tumor microenvironment.See related article by Biffi et al. p. 282.

Modulation of Redox Homeostasis by Inhibition of MTHFD2 in Colorectal Cancer: Mechanisms and Therapeutic Implications.

BACKGROUND: Overcoming oxidative stress is a critical step for tumor progression; however, the underlying mechanisms in colorectal cancer (CRC) remain unclear. METHODS: We investigated nicotinamide adenine dinucleotide (phosphate) (NAD(P))-dependent enzyme methylene tetrahydrofolate dehydrogenase 2 (MTHFD2) expression, clinical relevance, redox modification, and molecular mechanisms using the CRC cells and tissues (n = 462 paired samples). The antitumor effects of MTHFD2 inhibitor LY345899 on CRC tumorigenesis and metastasis were evaluated in vitro and in vivo. Data analysis used Kaplan-Meier, Pearson's correlation, and Student t test where appropriate. All statistical tests were two-sided. RESULTS: Here, we report that the patients with high expression of MTHFD2 have a shorter overall survival (HR = 1.62, 95% CI = 1.12 to 2.36, P = .01) and disease-free survival (HR = 1.55, 95% CI = 1.07 to 2.27, P = .02) than patients with low MTHFD2 expression. Suppression of MTHFD2 disturbs NADPH and redox homeostasis and accelerates cell death under oxidative stress, such as hypoxia or anchorage independence (P ≤ .01 for all). Also, genetic or pharmacological inhibition of MTHFD2 suppresses CRC cell growth and lung and peritoneal metastasis in cell-based xenografts (n = 5-8 mice per group). Importantly, LY345899 treatment statistically significantly suppresses tumor growth and decreases the tumor weight in CRC patient-derived xenograft models (n = 10 mice per group, mean [SD] tumor weight of the vehicle-treated group was 1.83 [0.19] mg vs 0.74 [0.30] mg for the LY345899-treated group, P < .001). CONCLUSIONS: Our study presents evidence that MTHFD2 confers redox homeostasis and promotes CRC cell growth and metastasis. The folate analog LY345899 as MTHFD2 inhibitor displays therapeutic activity against CRC and warrants further clinical investigation for CRC treatment.

Identification of cisplatin sensitizers through high-throughput combinatorial screening.

cis-Diamminedichloroplatinum/cisplatin (CDDP) is a major drug used in cancer chemotherapy; however, the toxic side-effects and development of drug resistance represent major challenges to the clinical use of CDDP. The aim of the present study was to identify effective drug combination regimens through high-throughput drug screening that can enhance the efficacy of CDDP, and to investigate the underlying mechanisms. A cell-based high-throughput screening methodology was implemented, using a library of 1,280 Food and Drug Administration (FDA)-approved drugs, to identify clinical compounds that act synergistically with CDDP. Our study identified two compounds, namely potassium antimony tartrate and topotecan, that significantly enhanced the sensitivity of colorectal and non-small cell lung cancer cells to CDDP. The synergistic action of both compounds with CDDP was confirmed by further quantitative analyses. Topotecan is a topoisomerase-1 inhibitor that has previously been shown to enhance the clinical response and overall patient survival when combined with CDDP by a yet unclear mechanism. We demonstrated that the combination of topotecan with CDDP significantly inhibited colony formation ability and increased the apoptosis of several cancer cell lines. Mechanistic analyses revealed that topotecan enhanced CDDP-induced DNA damage and inhibited the repair of DNA strand breaks, without affecting the cellular platinum content. Overall, the findings of this study demonstrated that the use of the FDA-approved drug panel in high-throughput screening is an effective method for identifying effective therapeutic regimens that are clinically relevant, and may have high feasibility for translation into clinical practice.

Long non-coding RNA UICLM promotes colorectal cancer liver metastasis by acting as a ceRNA for microRNA-215 to regulate ZEB2 expression.

Long non-coding RNAs (lncRNAs) are involved in the pathology of various tumors, including colorectal cancer (CRC). However, the role of lncRNA in CRC liver metastasis remains unclear. Methods: a microarray was performed to identify the differentially expressed lncRNAs between CRC tissues with and without liver metastasis. Survival analysis was evaluated using the Kaplan-Meier method and assessed using the log-rank test. In vitro and in vivo assays were preformed to explore the biological effects of the differentially expressed lncRNA in CRC cells. Results: the lncRNA UICLM (up-regulated in colorectal cancer liver metastasis) was significantly up-regulated in cases of CRC with liver metastasis. Moreover, UICLM expression was higher in CRC tissues than in normal tissues, and UICLM expression was associated with poor patient survival. Knockdown of UICLM inhibited CRC cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and CRC stem cell formation in vitro as well as tumor growth and liver metastasis in vivo. Ectopic expression of UICLM promoted CRC cell proliferation and invasion. Mechanistic investigations revealed that UICLM induced its biological effects by regulating ZEB2, as the oncogenesis facilitated by UICLM was inhibited by ZEB2 depletion. Further study indicated that UICLM acted as a competing endogenous RNA (ceRNA) for miR-215 to regulate ZEB2 expression. Conclusions: taken together, our findings demonstrate how UICLM induces CRC liver metastasis and may offer a novel prognostic marker and therapeutic target for this disease.

TAK-ing aim at chemoresistance: The emerging role of MAP3K7 as a target for cancer therapy.

Cellular drug resistance remains the main obstacle to the clinical efficacy of cancer chemotherapy. Alterations in key pathways regulating cell cycle checkpoints, apoptosis and Epithelial to Mesenchymal Transition (EMT), such as the Mitogen-activated protein kinase (MAPK) pathway, appear to be closely associated to cancer chemoresistance. Transforming growth factor-ß (TGF-ß)- activated kinase 1 (TAK1, also known as MAP3K7) is a serine/threonine kinase in the mitogen-activated protein kinase (MAP3K) family. It represents the cellular hub to which IL1, TGF-ß and Wnt signaling pathways converge. By regulating the phosphorylation status and activities of transcription factors including Activated Protein-1 (AP-1) and nuclear factor κ-B (NF-κB), TAK1 mediates inflammatory and pro-survival responses. The interest towards the therapeutic targeting of TAK1 is due to its identification as one of the main mediators of both chemoresistance and EMT in several types of tumors, and as the possible target for a subset of treatment-refractory colon cancers exhibiting mutated KRAS or activated WNT pathways. For these reasons, many efforts have been made to design inhibitors of TAK1 kinase activity, which could be used to reverse TAK1-mediated chemoresistance. The activity of these inhibitors, in combination with the most commonly used chemotherapeutic drugs, has been tested in preclinical studies, proving the efficacy of TAK1 inhibition in reducing tumor growth and survival following chemotherapy administration. In the first part of this review, we describe the mechanisms underlying TAK1 regulation such as phosphorylation, ubiquitination and targeting by microRNAs. We then focus on the development of therapeutic small molecule inhibitors of TAK1 kinase activity, as well as preclinical studies supporting the role of TAK1 as a potential target for enhancing the response of tumors to anticancer therapies.