CUX1: target of Akt signalling and mediator of resistance to apoptosis in pancreatic cancer

Mapping cardiac remodeling in chronic kidney disease

Patients with advanced chronic kidney disease (CKD) mostly die from sudden cardiac death and recurrent heart failure. The mechanisms of cardiac remodeling are largely unclear. To dissect molecular and cellular mechanisms of cardiac remodeling in CKD in an unbiased fashion, we performed left ventricular single-nuclear RNA sequencing in two mouse models of CKD. Our data showed a hypertrophic response trajectory of cardiomyocytes with stress signaling and metabolic changes driven by soluble uremia-related factors. We mapped fibroblast to myofibroblast differentiation in this process and identified notable changes in the cardiac vasculature, suggesting inflammation and dysfunction. An integrated analysis of cardiac cellular responses to uremic toxins pointed toward endothelin-1 and methylglyoxal being involved in capillary dysfunction and TNFα driving cardiomyocyte hypertrophy in CKD, which was validated in vitro and in vivo. TNFα inhibition in vivo ameliorated the cardiac phenotype in CKD. Thus, interventional approaches directed against uremic toxins, such as TNFα, hold promise to ameliorate cardiac remodeling in CKD.

Targeting the SOX2/CDP protein complex with a peptide suppresses the malignant progression of esophageal squamous cell carcinoma

Emerging evidence indicates that SOX2 is an oncogene for esophageal squamous cell carcinoma (ESCC). However, direct targeting of SOX2 is not feasible given that this transcription factor plays important roles in the maintenance of tissues such as the brain. Here, we identified CDP (Homeobox protein cut-like 1 or CASP) as a unique SOX2 binding partner enriched in ESCC with Duolink proximity ligation assay, bimolecular fluorescence complementation (BiFc) and immunoprecipitation. We then screened a peptide aptamer library using BiFc and immunoprecipitation and identified several peptide aptamers, including P58, that blocked the CDP/SOX2 interaction, leading to the inhibition of ESCC progress in vitro and in vivo. Upon administration, synthetic peptide P58, containing the YGRKKRRQRRR cell-penetrating peptide and the fluorophore TAMRA, also blocked the growth and metastasis of ESCC in both mice and zebrafish. Therefore, targeting the SOX2 binding partner CDP with peptide P58 offers an alternative avenue to treat ESCC with increased SOX2 levels.

CUT homeobox genes: transcriptional regulation of neuronal specification and beyond

CUT homeobox genes represent a captivating gene class fulfilling critical functions in the development and maintenance of multiple cell types across a wide range of organisms. They belong to the larger group of homeobox genes, which encode transcription factors responsible for regulating gene expression patterns during development. CUT homeobox genes exhibit two distinct and conserved DNA binding domains, a homeodomain accompanied by one or more CUT domains. Numerous studies have shown the involvement of CUT homeobox genes in diverse developmental processes such as body axis formation, organogenesis, tissue patterning and neuronal specification. They govern these processes by exerting control over gene expression through their transcriptional regulatory activities, which they accomplish by a combination of classic and unconventional interactions with the DNA. Intriguingly, apart from their roles as transcriptional regulators, they also serve as accessory factors in DNA repair pathways through protein-protein interactions. They are highly conserved across species, highlighting their fundamental importance in developmental biology. Remarkably, evolutionary analysis has revealed that CUT homeobox genes have experienced an extraordinary degree of rearrangements and diversification compared to other classes of homeobox genes, including the emergence of a novel gene family in vertebrates. Investigating the functions and regulatory networks of CUT homeobox genes provides significant understanding into the molecular mechanisms underlying embryonic development and tissue homeostasis. Furthermore, aberrant expression or mutations in CUT homeobox genes have been associated with various human diseases, highlighting their relevance beyond developmental processes. This review will overview the well known roles of CUT homeobox genes in nervous system development, as well as their functions in other tissues across phylogeny.

In silico discovery of small molecules for efficient stem cell differentiation into definitive endoderm

Improving methods for human embryonic stem cell differentiation represents a challenge in modern regenerative medicine research. Using drug repurposing approaches, we discover small molecules that regulate the formation of definitive endoderm. Among them are inhibitors of known processes involved in endoderm differentiation (mTOR, PI3K, and JNK pathways) and a new compound, with an unknown mechanism of action, capable of inducing endoderm formation in the absence of growth factors in the media. Optimization of the classical protocol by inclusion of this compound achieves the same differentiation efficiency with a 90% cost reduction. The presented in silico procedure for candidate molecule selection has broad potential for improving stem cell differentiation protocols.

MicroRNA-122 overexpression promotes apoptosis and tumor suppressor gene expression induced by microcystin-leucine arginine in mouse liver

Microcystin-leucine arginine (MC-LR), an important hepatoxin, has the effect of promoting hepatocarcinogenesis. MicroRNA-122 (miR-122), an important tumor suppressor in liver, plays an important role in promoting cell apoptosis. Previous studies found that the expression of miR-122 was reduced after MC-LR exposure in liver. In this study, C57BL/6 mice were exposed to saline, negative control agomir, and MC-LR with or without miR-122 agomir transfection. The results indicated that MC-LR promoted the expressions of tumor suppressor genes and decreased the expressions of anti-apoptotic proteins B cell lymphoma-2 (Bcl-2) and Bcl-2-like 2 (Bcl-w), causing hepatocyte apoptosis. Under MC-LR exposure, miR-122 agomir transfection could further increase the expressions of tumor suppressor genes and the release of cytochrome-c (Cyt-c) and decrease the expressions of Bcl-2 and Bcl-w. In conclusion, miR-122 reduction can mitigate MC-LR-induced apoptosis to a certain extent, which in turn, it is likely to have contributed to MC-LR-induced hepatocarcinogenesis.

Aberrant transcription factors in the cancers of the pancreas

Transcription factors (TFs) are essential for proper activation of gene set during the process of organogenesis, differentiation, lineage specificity. Reactivation or dysregulation of TFs regulatory networks could lead to deformation of organs, diseases including various malignancies. Currently, understanding the mechanism of oncogenesis became necessity for the development of targeted therapeutic strategy for different cancer types. It is evident that many TFs go awry in cancers of the pancreas such as pancreatic ductal adenocarcinoma (PDAC) and pancreatic neuroendocrine neoplasms (PanNENs). These mutated or dysregulated TFs abnormally controls various signaling pathways in PDAC and PanNENs including RTK, PI3K-PTEN-AKT-mTOR, JNK, TGF-β/SMAD, WNT/β-catenin, SHH, NOTCH and VEGF which in turn regulate different hallmarks of cancer. Aberrant regulation of such pathways have been linked to the initiation, progression, metastasis, and resistance in pancreatic cancer. As of today, a number of TFs has been identified as crucial regulators of pancreatic cancer and a handful of them shown to have potential as therapeutic targets in pre-clinical and clinical settings. In this review, we have summarized the current knowledge on the role and therapeutic usefulness of TFs in PDAC and PanNENs.

Base excision repair accessory factors in senescence avoidance and resistance to treatments

Cancer cells, in which the RAS and PI3K pathways are activated, produce high levels of reactive oxygen species (ROS), which cause oxidative DNA damage and ultimately cellular senescence. This process has been documented in tissue culture, mouse models, and human pre-cancerous lesions. In this context, cellular senescence functions as a tumour suppressor mechanism. Some rare cancer cells, however, manage to adapt to avoid senescence and continue to proliferate. One well-documented mode of adaptation involves increased production of antioxidants often associated with inactivation of the KEAP1 tumour suppressor gene and the resulting upregulation of the NRF2 transcription factor. In this review, we detail an alternative mode of adaptation to oxidative DNA damage induced by ROS: the increased activity of the base excision repair (BER) pathway, achieved through the enhanced expression of BER enzymes and DNA repair accessory factors. These proteins, exemplified here by the CUT domain proteins CUX1, CUX2, and SATB1, stimulate the activity of BER enzymes. The ensued accelerated repair of oxidative DNA damage enables cancer cells to avoid senescence despite high ROS levels. As a by-product of this adaptation, these cancer cells exhibit increased resistance to genotoxic treatments including ionizing radiation, temozolomide, and cisplatin. Moreover, considering the intrinsic error rate associated with DNA repair and translesion synthesis, the elevated number of oxidative DNA lesions caused by high ROS leads to the accumulation of mutations in the cancer cell population, thereby contributing to tumour heterogeneity and eventually to the acquisition of resistance, a major obstacle to clinical treatment.

N6-Methyladenosine Methylome Profiling of Muscle and Adipose Tissues Reveals Methylase-mRNA Metabolic Regulatory Networks in Fat Deposition of Rex Rabbits

N6-methyladenosine (m6A) is the most prevalent internal form of modification in messenger RNA in higher eukaryotes and plays an important role in cancer, immunity, reproduction, development, and fat deposition. Intramuscular fat is the main factor used to measure the meat quality of an animal. The deposition of intramuscular fat and perirenal fat increases with age. However, there is no data on m6A modification of Rex rabbits and its potential biological roles in adipose deposition and muscle growth. Here, we performed two high-throughput sequencing methods, m6A-modified RNA immunoprecipitation sequence (MeRIP-seq) and RNA sequence (RNA-seq), to identify key genes with m6A modification on fat deposition in the muscle and adipose tissues of Rex rabbits. Then, qRT-PCR was used to identify the differently methylated genes related to fat deposition. Our findings showed that there were 12,876 and 10,973 m6A peaks in the rabbit muscle and adipose tissue transcriptomes, respectively. Stop codons, 3′-untranslated regions, and coding regions were found to be mainly enriched for m6A peaks. In addition, we found 5 differential methylases and 12 key genes of methylation modification related to fat deposition between muscle and adipose tissues samples. The expression levels of six random key genes were significantly higher in the fat than that in the muscle of Rex rabbits at different stages (p < 0.01). Finally, five differential methylases were found to regulate adipogenesis by affecting the expression of screened genes in different ways. These findings provided a theoretical basis for our future research on the function of m6A modification during the growth of fat deposits.

Genomic studies controvert the existence of the CUX1 p75 isoform

CUX1, encoding a homeodomain-containing transcription factor, is recurrently deleted or mutated in multiple tumor types. In myeloid neoplasms, CUX1 deletion or mutation carries a poor prognosis. We have previously established that CUX1 functions as a tumor suppressor in hematopoietic cells across multiple organisms. Others, however, have described oncogenic functions of CUX1 in solid tumors, often attributed to truncated CUX1 isoforms, p75 and p110, generated by an alternative transcriptional start site or post-translational cleavage, respectively. Given the clinical relevance, it is imperative to clarify these discrepant activities. Herein, we sought to determine the CUX1 isoforms expressed in hematopoietic cells and find that they express the full-length p200 isoform. Through the course of this analysis, we found no evidence of the p75 alternative transcript in any cell type examined. Using an array of orthogonal approaches, including biochemistry, proteomics, CRISPR/Cas9 genomic editing, and analysis of functional genomics datasets across a spectrum of normal and malignant tissue types, we found no data to support the existence of the CUX1 p75 isoform as previously described. Based on these results, prior studies of p75 require reevaluation, including the interpretation of oncogenic roles attributed to CUX1.

Nonviral siRNA delivery systems for pancreatic cancer therapy

The serious drawbacks of the conventional treatment of pancreatic ductal adenocarcinoma (PDAC) such as nonspecific toxicity and high resistance to chemo and radiation therapy, have prompted the development and application of countless small interfering RNA (siRNA)-based therapeutics. Recent advances in drug delivery systems hold great promise for improving siRNA-based therapeutics and developing a new class of drugs, known as nano-siRNA drugs. However, many fundamental questions, regarding toxicity, immunostimulation, and poor knowledge of nano-bio interactions, need to be addressed before clinical translation. In this review, we provide recent achievements in the design and development of various nonviral delivery vehicles for pancreatic cancer therapy. More importantly, codelivery of conventional anticancer drugs with siRNA as a new revolutionary pancreatic cancer combinational therapy is completely discussed.

TIPE2 Suppresses Malignancy of Pancreatic Cancer Through Inhibiting TGFβ1 Mediated Signaling Pathway

Pancreatic cancer is one of the major reasons of cancer-associated deaths due to poor diagnosis, high metastasis and drug resistance. Therefore, it is important to understand the cellular and molecular mechanisms of pancreatic cancer to identify new targets for the treatment. TIPE2 is an essential regulator of tumor apoptosis, inflammation and immune homeostasis. However, the role of TIPE2 is still not fully understood in pancreatic cancer. In this study, we found the expression of TIPE2 was decreased in pancreatic cancer tissues compare to paracancerous tissues, which was negatively correlated with tumor size in patients. Overexpression of TIPE2 significantly decreased cell proliferation, metastasis and increased apoptotic events in pancreatic cancer cell lines. Moreover, the results obtained from real time PCR and western blot revealed that TIPE2 was also involved in inhibiting MMPs and N-Cadherin expression while increasing Bax expression in pancreatic cancer cells. Similarly, TIPE2 could inhibit tumor growth in vivo, decrease the expression of Ki-67 and N-Cadherin, and increase the expression of Bax by IHC analysis in tumor tissues isolated from tumor-bearing mice. Mechanistic studies exhibited that TIPE2 might suppress pancreatic cancer development through inhibiting PI3K/AKT and Raf/MEK/ERK signaling pathways triggered by TGFβ1. Moreover, the tumor-infiltrating lymphocytes from tumor-bearing mice were analyzed by flow cytometry, and showed that TIPE2 could promote T cell activation to exert an anti-tumor effect possibly through activation of DCs in a TGFβ1 dependent manner. In general, we described the multiple regulatory mechanisms of TIPE2 in pancreatic tumorigenesis and tumor microenvironment, which suggested TIPE2 may act as a potential therapeutic target in pancreatic cancer.

CUT Domain Proteins in DNA Repair and Cancer

Simple Summary

Genetic integrity is ensured by complex groups of proteins involved in DNA repair. In particular, base damage is repaired by enzymes of the base excision repair pathway. Recent studies have revealed that some transcription factors can function as accessory factors that stimulate the enzymatic activities of these DNA repair enzymes. It is well known that defects in DNA repair mechanisms cause the accumulation of changes in DNA, called mutations, that increase the possibility that cells become tumorigenic. Paradoxically, once they have emerged certain cancer cells are acutely dependent on the heightened activities of base excision repair enzymes because their metabolism generates highly reactive molecules that cause multiple types of damage to bases. In this context, the function of accessory factors becomes essential to cancer cell survival. As a by-product of this adaptation, cancer cells become more resistant to therapies that cause DNA damage, such as chemotherapy and radiation.

Abstract

Recent studies revealed that CUT domains function as accessory factors that accelerate DNA repair by stimulating the enzymatic activities of the base excision repair enzymes OGG1, APE1, and DNA pol β. Strikingly, the role of CUT domain proteins in DNA repair is exploited by cancer cells to facilitate their survival. Cancer cells in which the RAS pathway is activated produce an excess of reactive oxygen species (ROS) which, if not counterbalanced by increased production of antioxidants, causes sustained oxidative DNA damage and, ultimately, cell senescence. These cancer cells can adapt by increasing their capacity to repair oxidative DNA damage in part through elevated expression of CUT domain proteins such as CUX1, CUX2, or SATB1. In particular, CUX1 overexpression was shown to cooperate with RAS in the formation of mammary and lung tumors in mice. Conversely, knockdown of CUX1, CUX2, or SATB1 was found to be synthetic lethal in cancer cells exhibiting high ROS levels as a consequence of activating mutations in KRAS, HRAS, BRAF, or EGFR. Importantly, as a byproduct of their adaptation, cancer cells that overexpress CUT domain proteins exhibit increased resistance to genotoxic treatments such as ionizing radiation, temozolomide, and cisplatin.

ATM: Main Features, Signaling Pathways, and Its Diverse Roles in DNA Damage Response, Tumor Suppression, and Cancer Development

ATM is among of the most critical initiators and coordinators of the DNA-damage response. ATM canonical and non-canonical signaling pathways involve hundreds of downstream targets that control many important cellular processes such as DNA damage repair, apoptosis, cell cycle arrest, metabolism, proliferation, oxidative sensing, among others. Of note, ATM is often considered a major tumor suppressor because of its ability to induce apoptosis and cell cycle arrest. However, in some advanced stage tumor cells, ATM signaling is increased and confers remarkable advantages for cancer cell survival, resistance to radiation and chemotherapy, biosynthesis, proliferation, and metastasis. This review focuses on addressing major characteristics, signaling pathways and especially the diverse roles of ATM in cellular homeostasis and cancer development.

CUX1 Enhances Pancreatic Cancer Formation by Synergizing with KRAS and Inducing MEK/ERK-Dependent Proliferation

Simple Summary

In pancreatic cancer, CUX1 acts as an important mediator of tumor cell proliferation and resistance to apoptosis. Using two different mouse models for the prevalent CUX1 isoforms p200 and p110, we identified p110 CUX1 as the major isoform promoting pancreatic cancer formation in the context of mutant KRAS. We could show an enhanced proliferation by activating and potentiating MEK-ERK signaling via an increased upstream activation of the ADAM17-EGFR axis. This strengthened activation in a KRAS-dependent manner, leading to a dramatically more accelerated formation of invasive PDAC in p110 CUX1 mice within 4 weeks. These results provide the first in vivo evidence for the importance of CUX1 in the development of pancreatic cancer, and highlight CUX1-dependent signaling pathways as potential therapeutic targets.

Abstract

The transcription factor CUX1 has been implicated in either tumor suppression or progression, depending on the cancer entity and the prevalent CUX1 isoform. Previously, we could show that CUX1 acts as an important mediator of tumor cell proliferation and resistance to apoptosis in pancreatic cancer cell lines. However, in vivo evidence for its impact on pancreatic carcinogenesis, isoform-specific effects and downstream signaling cascades are missing. We crossbred two different CUX1 isoform mouse models (p200 CUX1 and p110 CUX1) with KC (KrasLSL-G12D/+; Ptf1aCre/+) mice, a genetic model for pancreatic precursor lesions (PanIN). In the context of oncogenic KRASs, both mice KCCux1p200 and KCCux1p110 led to increased PanIN formation and development of invasive pancreatic ductal adenocarcinomata (PDAC). In KCCux1p110 mice, tumor development was dramatically more accelerated, leading to formation of invasive PDAC within 4 weeks. In vitro and in vivo, we could show that CUX1 enhanced proliferation by activating MEK-ERK signaling via an upstream increase of ADAM17 protein, which in turn led to an activation of EGFR. Additionally, CUX1 further enhanced MEK-ERK activation through upregulation of the serine/threonine kinase MOS, phosphorylating MEK in a KRAS-independent manner. We identified p110 CUX1 as major driver of pancreatic cancer formation in the context of mutant KRAS. These results provide the first in vivo evidence for the importance of CUX1 in the development of pancreatic cancer, and highlight the importance of CUX1-dependent signaling pathways as potential therapeutic targets.

Cut-like homeobox 1 (CUX1) tumor suppressor gene haploinsufficiency induces apoptosis evasion to sustain myeloid leukemia

While oncogenes promote tumorigenesis, they also induce deleterious cellular stresses, such as apoptosis, that cancer cells must combat by coopting adaptive responses. Whether tumor suppressor gene haploinsufficiency leads to such phenomena and their mechanistic basis is unclear. Here, we demonstrate that elevated levels of the anti-apoptotic factor, CASP8 and FADD-like apoptosis regulator (CFLAR), promotes apoptosis evasion in acute myeloid leukemia (AML) cells haploinsufficient for the cut-like homeobox 1 (CUX1) transcription factor, whose loss is associated with dismal clinical prognosis. Genome-wide CRISPR/Cas9 screening identifies CFLAR as a selective, acquired vulnerability in CUX1-deficient AML, which can be mimicked therapeutically using inhibitor of apoptosis (IAP) antagonists in murine and human AML cells. Mechanistically, CUX1 deficiency directly alleviates CUX1 repression of the CFLAR promoter to drive CFLAR expression and leukemia survival. These data establish how haploinsufficiency of a tumor suppressor is sufficient to induce advantageous anti-apoptosis cell survival pathways and concurrently nominate CFLAR as potential therapeutic target in these poor-prognosis leukemias.

CUT Domains Stimulate Pol β Enzymatic Activities to Accelerate Completion of Base Excision Repair

The full-length CUX1 protein isoform was previously shown to function as an auxiliary factor in base excision repair (BER). Specifically, CUT domains within CUX1 stimulate the enzymatic activities of the OGG1 DNA glycosylase and APE1 endonuclease. Moreover, ectopic expression of CUX1 or CUT domains increased the resistance of cancer cells to treatments that cause oxidative DNA damage and mono-alkylation of bases. Stimulation of OGG1 AP/lyase and APE1 endonuclease activities, however, cannot explain how CUT domains confer resistance to these treatments since these enzymes produce DNA single-strand breaks that are highly toxic to cells. In the present study, we show that CUT domains stimulate the polymerase and deoxyribose phosphate (dRP)-lyase activities of DNA polymerase β to promote BER completion. In agreement with these results, CUX1 knockdown decreases BER completion in cell extracts and causes an increase in the number of abasic sites in genomic DNA following temozolomide treatment. We also show that CUT domains stimulate bypass of intrastrand G-crosslinks by Pol β in vitro, while the resistance of cancer cells to cisplatin treatment is reduced by CUX1 knockdown but restored by ectopic expression of CUT domains. Altogether our results establish CUX1 as an important auxiliary factor that stimulates multiple steps of base excision repair, from the recognition and removal of altered bases to the addition of new nucleotides and removal of 5'-deoxyribose phosphate required for ligation and BER completion. These findings provide a mechanistic explanation for the observed correlation between CUX1 expression and the resistance of cancer cells to genotoxic treatments.

Targeting cancer-cell mitochondria and metabolism to improve radiotherapy response

Radiotherapy is a regimen that uses ionising radiation (IR) to treat cancer. Despite the availability of several therapeutic options, cancer remains difficult to treat and only a minor percentage of patients receiving radiotherapy show a complete response to the treatment due to development of resistance to IR (radioresistance). Therefore, radioresistance is a major clinical problem and is defined as an adaptive response of the tumour to radiation-induced damage by altering several cellular processes which sustain tumour growth including DNA damage repair, cell cycle arrest, alterations of oncogenes and tumour suppressor genes, autophagy, tumour metabolism and altered reactive oxygen species. Cellular organelles, in particular mitochondria, are key players in mediating the radiation response in tumour, as they regulate many of the cellular processes involved in radioresistance. In this article has been reviewed the recent findings describing the cellular and molecular mechanism by which cancer rewires the function of the mitochondria and cellular metabolism to enhance radioresistance, and the role that drugs targeting cellular bioenergetics have in enhancing radiation response in cancer patients.

PIK3CA Is Regulated by CUX1, Promotes Cell Growth and Metastasis in Bladder Cancer via Activating Epithelial-Mesenchymal Transition

PIK3CA is a key component of phosphatidylinositol 3-kinase (PI3K) pathway that its involvement in tumorigenesis has been revealed by previous research. However, its functions and potential mechanisms in bladder cancer are still largely undiscovered. Tissue microarray (TMA) with 66 bladder cancer patients was surveyed via immunohistochemistry to evaluate the level of PIK3CA and CUX1 and we found upregulation of PIK3CA in bladder cancer tissue and patients with higher level of PIK3CA presented with poorer prognosis. Overly expressed PIK3CA promoted growth, migration, invasion, and metastasis of bladder cancer cells and knockdown of PIK3CA had the opposite effect. Gain-of-function and loss-of-function studies showed that PIK3CA expression was facilitated by CUX1, leading to activation of epithelial-mesenchymal transition (EMT), accompanied by upregulated expression of Snail, β-catenin, Vimentin and downregulated expression of E-cadherin in the bladder cancer cell lines. Besides, over-expressed CUX1 could restore the expression of downregulated Snail, β-catenin, Vimentin and E-cadherin which was induced by PIK3CA knockdown. These results revealed that PIK3CA overexpression in bladder cancer was regulated by the transcription factor CUX1, and PIK3CA exerted its biological effects by activating EMT.

Nanoparticle-complexed antimiRs for inhibiting tumor growth and metastasis in prostate carcinoma and melanoma

Background

MiRNAs act as negative regulators of gene expression through target mRNA degradation or inhibition of its translation. In cancer, several miRNAs are upregulated and play crucial roles in tumorigenesis, making the inhibition of these oncomiRs an interesting therapeutic approach. This can be achieved by directly complementary single-stranded anti-miRNA oligonucleotides (antimiRs). A major bottleneck in antimiR therapy, however, is their efficient delivery. The nanoparticle formation with polyethylenimine (PEI) may be particularly promising, based on the PEI’s ability to electrostatically interact with oligonucleotides. This leads to their protection and supports delivery. In the present study, we explore for the first time PEI for antimiR formulation and delivery. We use the branched low molecular weight PEI F25-LMW for the complexation of different antimiRs, and analyse tumor- and metastasis-inhibitory effects of PEI/antimiR complexes in different tumor models.

Results

In prostate carcinoma, transfection of antimiRs against miR-375 and miR-141 leads to tumor cell inhibition in 2D- and 3D-models. More importantly, an in vivo tumor therapy study in prostate carcinoma xenografts reveals anti-tumor effects of the PEI/antimiR complexes. In advanced melanoma and metastasis, we identify by a microRNA screen miR-150 as a particularly relevant oncomiR candidate, and validate this result in vitro and in vivo. Again, the systemic application of PEI/antimiR complexes inhibiting this miRNA, or the previously described antimiR-638, leads to profound tumor growth inhibition. These effects are associated with the upregulation of direct miRNA target genes. In a melanoma metastasis mouse model, anti-metastatic effects of PEI/antimiR treatment are observed as well.

Conclusions

We thus describe PEI-based complexes as efficient platform for antimiR therapy, as determined in two different tumor entities using in vivo models of tumor growth or metastasis. Our study also highlights the therapeutic relevance of miR-375, miR-141, miR-150 and miR-638 as target miRNAs for antimiR-mediated inhibition.

The involvement of noncanonical Wnt signaling in cancers

Wnt signaling is one of the key cascades regulating normal tissue development and has been tightly associated with cancer. The Wnt signaling can be subdivided into two categories: canonical & noncanonical. Noncanonical Wnt signaling pathways mainly include Wnt/PCP (planar cell polarity) signaling and Wnt-cGMP (cyclic guanosine monophosphate) /Ca2+ signaling. It has been well studied by previous researches that noncanonical Wnt signaling regulates multiple cell functions including proliferation, differentiation, adhesion, polarity, motility, and migration. The aberrant activation or inhibition of noncanonical Wnt signaling is crucial in cancer progression, exerting both oncogenic and tumor-suppressive effects. Recent studies show the involvement of noncanonical Wnt in regulating cancer cell invasion, metastasis, metabolism, and inflammation. Here, we review current insights into novel components of non-canonical signalings and describe their involvement in various cancer types. We also summarize recent biological and clinical discoveries that outline non-canonical Wnt signaling in tumorigenesis. Finally, we provide an overview of current strategies to target non-canonical Wnt signaling in cancer and challenges that are associated with such approaches.

Cathepsin Inhibition Modulates Metabolism and Polarization of Tumor-Associated Macrophages

Simple Summary

Stroma-infiltrating tumor-associated macrophages (TAM) play an important role in regulating tumor progression and chemoresistance. Many tumor-infiltrating macrophage populations can be identified by preferential expression of distinct marker genes associated with an M2 phenotype and may execute tumor-promoting functions by enhancing tissue remodeling, facilitating angiogenesis, and suppressing immune responses. In this study, we aimed to characterize the impact of cathepsins in maintaining the TAM phenotype. For this purpose, we investigated the molecular effects of cathepsin inhibition on the viability and polarization of human primary macrophages as well as its metabolic consequences. Pharmacological inhibition of cathepsins B, L, and S using a novel inhibitor, GB111-NH₂, led to a polarization shift from M2- to M1 macrophages, associated with distinct alterations in lysosomal signaling and lipid metabolism. This could be therapeutically exploited in tumors with strong infiltration of M2-macrophages, thereby possibly reverting M2 polarization, overcoming drug resistance, and improving the prognosis of our patients.

Abstract

Stroma-infiltrating immune cells, such as tumor-associated macrophages (TAM), play an important role in regulating tumor progression and chemoresistance. These effects are mostly conveyed by secreted mediators, among them several cathepsin proteases. In addition, increasing evidence suggests that stroma-infiltrating immune cells are able to induce profound metabolic changes within the tumor microenvironment. In this study, we aimed to characterize the impact of cathepsins in maintaining the TAM phenotype in more detail. For this purpose, we investigated the molecular effects of pharmacological cathepsin inhibition on the viability and polarization of human primary macrophages as well as its metabolic consequences. Pharmacological inhibition of cathepsins B, L, and S using a novel inhibitor, GB111-NH₂, led to changes in cellular recycling processes characterized by an increased expression of autophagy- and lysosome-associated marker genes and reduced adenosine triphosphate (ATP) content. Decreased cathepsin activity in primary macrophages further led to distinct changes in fatty acid metabolites associated with increased expression of key modulators of fatty acid metabolism, such as fatty acid synthase (FASN) and acid ceramidase (ASAH1). The altered fatty acid profile was associated with an increased synthesis of the pro-inflammatory prostaglandin PGE₂, which correlated with the upregulation of numerous NF_kB-dependent pro-inflammatory mediators, including interleukin-1 (IL-1), interleukin-6 (IL-6), C-C motif chemokine ligand 2 (CCL2), and tumor necrosis factor-alpha (TNFα). Our data indicate a novel link between cathepsin activity and metabolic reprogramming in macrophages, demonstrated by a profound impact on autophagy and fatty acid metabolism, which facilitates a pro-inflammatory micromilieu generally associated with enhanced tumor elimination. These results provide a strong rationale for therapeutic cathepsin inhibition to overcome the tumor-promoting effects of the immune-evasive tumor micromilieu.

CUX1-Transcriptional Master Regulator of Tumor Progression in Pancreatic Neuroendocrine Tumors

Recently, we identified the homeodomain transcription factor Cut homeobox 1 (CUX1) as mediator of tumour de-differentiation and metastatic behaviour in human insulinoma patients. In insulinomas, CUX1 enhanced tumour progression by stimulating proliferation and angiogenesis in vitro and in vivo. In patients with non-functional pancreatic neuroendocrine tumours (PanNET), however, the impact of CUX1 remains to be elucidated. Here, we analysed CUX1 expression in two large independent cohorts (n = 43 and n = 141 tissues) of non-functional treatment-naïve and pre-treated PanNET patients, as well as in the RIP1Tag2 mouse model of pancreatic neuroendocrine tumours. To further assess the functional role of CUX1, expression profiling of DNA damage-, proliferation- and apoptosis-associated genes was performed in CUX1-overexpressing Bon-1 cells. Validation of differentially regulated genes was performed in Bon-1 and QGP1 cells with knock-down and overexpression strategies. CUX1 expression assessed by a predefined immunoreactivity score (IRS) was significantly associated with shorter progression-free survival (PFS) of pre-treated PanNET patients (23 vs. 8 months; p = 0.005). In treatment-naïve patients, CUX1 was negatively correlated with grading and recurrence-free survival (mRFS of 39 versus 8 months; p = 0.022). In both groups, high CUX1 levels indicated a metastatic phenotype. Functionally, CUX1 upregulated expression of caspases and death associated protein kinase 1 (DAPK1), known as mediators of tumour progression and resistance to cytotoxic drugs. This was also confirmed in both cell lines and human tissues. In the RIP1Tag2 mouse model, CUX1 expression was associated with advanced tumour stage and resistance to apoptosis. In summary, we identified the transcription factor CUX1 as mediator of tumour progression in non-functional PanNET in vitro and in vivo, indicating that the CUX1-dependent signalling network is a promising target for future therapeutic intervention.

Distinct clinical and biological implications of CUX1 in myeloid neoplasms

Somatic mutations of the CUT-like homeobox 1 (CUX1) gene (CUX1 ^MT) can be found in myeloid neoplasms (MNs), in particular, in myelodysplastic syndromes (MDSs). The CUX1 locus is also deleted in 3 of 4 MN cases with -7/del(7q). A cohort of 1480 MN patients was used to characterize clinical features and clonal hierarchy associated with CUX1 ^MT and CUX1 deletions (CUX1 ^DEL) and to analyze their functional consequences in vitro. CUX1 ^MT were present in 4% of chronic MNs. CUX1 ^DEL were preferentially found in advanced cases (6%). Most MDS and acute myeloid leukemia (AML) patients with -7/del(7q) and up to 15% of MDS patients and 5% of AML patients diploid for the CUX1 locus exhibited downmodulated CUX1 expression. In 75% of mutant cases, CUX1 ^MT were heterozygous, whereas microdeletions and homozygous and compound-heterozygous mutations were less common. CUX ^MT/DEL were associated with worse survival compared with CUX1 ^WT Within the clonal hierarchy, 1 of 3 CUX1 ^MT served as founder events often followed by secondary BCOR and ASXL1 subclonal hits, whereas TET2 was the most common ancestral lesion, followed by subclonal CUX1 ^MT Comet assay of patients' bone marrow progenitor cells and leukemic cell lines performed in various experimental conditions revealed that frameshift mutations, hemizygous deletions, or experimental CUX1 knockdown decrease the repair of oxidized bases. These functional findings may explain why samples with either CUX1 ^MT or low CUX1 expression coincided with significantly higher numbers of somatic hits by whole-exome sequencing. Our findings implicate the DNA repair dysfunction resulting from CUX1 lesions in the pathogenesis of MNs, in which they lead to a mutator phenotype.

CUX1, A Controversial Player in Tumor Development

CUX1 belongs to the homeodomain transcription factor family and is evolutionarily and functionally conserved from Drosophila to humans. In addition to the involvement in various physiological events including tissue development, cell proliferation, differentiation and migration, and DNA damage response, CUX1 has been implicated in tumorigenesis. Interestingly, CUX1 has been recently recognized as a haploinsufficient tumor suppressor, which is paradoxically overexpressed in tumor cells. While loss of heterozygosity and/or mutations of CUX1 have been frequently detected in many types of cancers, genomic amplification, and overexpression of CUX1 have also been reported in cancer tissues and are correlated with higher tumor grade and poor prognosis. Therefore, deciphering the roles of different CUX1 isoforms and in different tumor stages is required to establish a CUX1-based therapeutic strategy for cancer treatment.

Integrative analysis of DNA methylation and gene expression in papillary renal cell carcinoma

Patterns of DNA methylation are significantly altered in cancers. Interpreting the functional consequences of DNA methylation requires the integration of multiple forms of data. The recent advancement in the next-generation sequencing can help to decode this relationship and in biomarker discovery. In this study, we investigated the methylation patterns of papillary renal cell carcinoma (PRCC) and its relationship with the gene expression using The Cancer Genome Atlas (TCGA) multi-omics data. We found that the promoter and body of tumor suppressor genes, microRNAs and gene clusters and families, including cadherins, protocadherins, claudins and collagens, are hypermethylated in PRCC. Hypomethylated genes in PRCC are associated with the immune function. The gene expression of several novel candidate genes, including interleukin receptor IL17RE and immune checkpoint genes HHLA2, SIRPA and HAVCR2, shows a significant correlation with DNA methylation. We also developed machine learning models using features extracted from single and multi-omics data to distinguish early and late stages of PRCC. A comparative study of different feature selection algorithms, predictive models, data integration techniques and representations of methylation data was performed. Integration of both gene expression and DNA methylation features improved the performance of models in distinguishing tumor stages. In summary, our study identifies PRCC driver genes and proposes predictive models based on both DNA methylation and gene expression. These results on PRCC will aid in targeted experiments and provide a strategy to improve the classification accuracy of tumor stages.

The transcription factor CUX1 negatively regulates invasion in castrate resistant prostate cancer

Metastatic prostate cancer is treated with androgen ablation therapy but progress to castrate resistant prostate cancer (CRPC). This study aimed to investigate the role of CUX1 in CRPC using clinical samples and in vitro models. CUX1 expression was increased in androgen-independent cells compared to androgen-sensitive cells. The multi-isoform nature of CUX1 makes it difficult to assay in tissue microarrays as there is no epitope able to distinguish the many isoforms for immunohistochemistry. Using surrogate markers, we found no differential expression between castrate resistant and local hormone naïve tissue. However, differences have been demonstrated at the transcript level. In androgen-sensitive cells, migration, but not invasion, increased following CUX1 knockdown. Conversely, in androgen-independent cells, invasion was increased. This observed difference in invasion capacity is not E-cadherin mediated, as CUX1 knockdown increases the expression of E-cadherin in both cell lines with no inter-cell line difference. Cells expressed different ratios of p110/p200 isoforms depending on androgen status and cathepsin L was only detectable in androgen-sensitive cells. MMP3 is upregulated in the androgen-independent cells. Rather than a simple presence or absence of CUX1, the relative balance of CUX1 isoforms and their interplay may be a significant factor in the functional role of CUX1 in CRPC.

Targeting the undruggable in pancreatic cancer using nano-based gene silencing drugs

Pancreatic cancer is predicted to be the second leading cause of cancer-related death by 2025. The best chemotherapy only extends survival by an average of 18 weeks. The extensive fibrotic stroma surrounding the tumor curbs therapeutic options as chemotherapy drugs cannot freely penetrate the tumor. RNA interference (RNAi) has emerged as a promising approach to revolutionize cancer treatment. Small interfering RNA (siRNA) can be designed to inhibit the expression of any gene which is important given the high degree of genetic heterogeneity present in pancreatic tumors. Despite the potential of siRNA therapies, there are hurdles limiting their clinical application such as poor transport across biological barriers, limited cellular uptake, degradation, and rapid clearance. Nanotechnology can address these challenges. In fact, the past few decades have seen the conceptualization, design, pre-clinical testing and recent clinical approval of a RNAi nanodrug to treat disease. In this review, we comment on the current state of play of clinical trials evaluating siRNA nanodrugs and review pre-clinical studies investigating the efficacy of siRNA therapeutics in pancreatic cancer. We assess the physiological barriers unique to pancreatic cancer that need to be considered when designing and testing new nanomedicines for this disease.

Upregulated Expression of CUX1 Correlates with Poor Prognosis in Glioma Patients: a Bioinformatic Analysis

Cut-like homeobox-1 (CUX1) is expressed in the upper layer of the cortex and participates in DNA replication, cell cycle control, and DNA repair. It has been shown to be involved in the proliferation of various types of solid tumors. The aims of this study were to explore the relationship between CUX1 expression and the prognosis of glioma by performing a series of functional experiments and bioinformatic analyses. Firstly, we found that CUX1 expression levels differed among patients with different grades of gliomas, and they were significantly correlated with the prognosis of glioma patients according to an analysis of data from a public database. qRT-PCR, western blotting, and immunohistochemical analysis of CUX1 were performed to demonstrate that the expression of CUX1 was positively correlated with the glioma WHO grade (P < 0.05) and several malignant clinical pathological parameters, including Ki67 and P53mut. In addition, the multivariate Cox regression and Kaplan-Meier curves showed that CUX1 expression exerted predictive value for overall survival. Finally, to further investigate the functions of CUX1, we identified CUX1-associated genes and, though GO/KEGG analysis, their associated biological functions and signaling pathways; the results suggested that the activity of CUX1 might be exerted via the JAK-STAT pathway or other key regulators of the cell cycle to promote proliferation, inflammation, and chemotherapy resistance in glioma. Taken together, these results indicate that CUX1 is a potential biomarker of malignancy and prognosis and may serve as a potential therapeutic target for glioma patients.

Interaction between somatostatin analogues and targeted therapies in neuroendocrine tumor cells

Somatostatin analogues (SSA) represent the standard of care for symptom control in patients with functional gastro-entero-pancreatic neuroendocrine tumors (GEP-NET). In addition, SSA exert significant anti-proliferative effects in mid-gut and pancreatic NET (PanNET). In parallel, molecularly targeted therapies (MTT) have been shown to improve progression free survival (PFS) in patients with PanNET. However, due to either primary or acquired resistance to MTT, their impact on overall survival (OS) remains unclear. To date, various hypotheses exist to explain differences in patient responsiveness to SSA and MTT. However, data addressing one of the most pivotal questions, whether combining SSA with novel MTT will result in synergistic or additive efficacy compared to monotherapy, are lacking. The aim of this study is to characterize the interaction, optimal sequence and dosing of SSA-based and molecularly targeted therapies in PanNET. Somatostatin receptor subtypes 1–5 (SSTR) were evaluated in the neuroendocrine cell lines Bon1, QGP1 and Ins-1 via immunoblot and qRT-PCR. The impact of the SSA-analogue lanreotide alone or in combination with the MTT sunitinib, everolimus and regorafenib on intracellular signalling, hormone secretion and cell proliferation was determined in cell lysates and supernatants. In addition, synergistic effects of SSA and MTT in various sequential therapeutic approaches were investigated. SSTR were differently expressed in the examined neuroendocrine tumor cell lines. SSTR modulation via lanreotide moderately influenced proliferation, mainly via modulating AKT and ERK signalling, which was paralleled by decreased chromogranin A (CgA) expression and secretion. Interestingly, MTT treatment with regorafenib upregulated the expression of SSTR-2 and -5, while sunitinib and everolimus did not significantly alter SSTR expression. Cell viability was significantly reduced by all MTT, with regorafenib exerting the most significant effects. However, compared to the marked effects of MTT alone, synergistic effects of combined MTT and lanreotide treatment were only modest and time- and dose-dependent. SSTR are differentially expressed in various NEN cell lines. Their expression is influenced by MTT treatment. Various sequential or simultaneous combinations of lanreotide and MTT did not lead to significant synergistic effects.

5-Hydroxytryptamine Receptor 1D Aggravates Hepatocellular Carcinoma Progression Through FoxO6 in AKT-Dependent and Independent Manners

Serotonin and its receptors have been shown to play critical regulatory roles in cancer biology. Nevertheless, the contributions of 5-hydroxytryptamine 1D (5-HT1D), an indispensable member of the serotonergic system, to hepatocellular carcinoma (HCC) remain unknown. The present study demonstrated that the 5-HT1D expression level was significantly up-regulated in HCC tissues and cell lines. The 5-HT1D expression level was closely correlated with unfavorable clinicopathological characteristics. Survival analyses show that elevated 5-HT1D expression level predicts poor overall survival and high recurrence probability in HCC patients. Functional studies revealed that 5-HT1D significantly promoted HCC proliferation, epithelial-mesenchymal transition, and metastasis in vitro and in vivo. Mechanistically, 5-HT1D could stabilize PIK3R1 by inhibiting its ubiquitin-mediated degradation. The interaction between 5-HT1D and phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) enhanced the expression of FoxO6 through the PI3K/Akt signaling pathway; FoxO6 could also be directly transcriptionally activated by 5-HT1D in an Akt-independent manner. MicroRNA-599 was found to be an upstream suppressive modulator of 5-HT1D. Additionally, 5-HT1D could attenuate tryptophan hydroxylase 1 expression through the PI3K/Akt/cut-like homeobox 1 axis in HCC. Conclusion: Herein, we uncovered the potent oncogenic effect of 5-HT1D on HCC by interacting with PIK3R1 to activate the PI3K/Akt/FoxO6 pathway, and provided a potential therapeutic target for HCC.

CUX1 stimulates APE1 enzymatic activity and increases the resistance of glioblastoma cells to the mono-alkylating agent temozolomide

Background

Cut Like homeobox 1 (CUX1), which encodes an auxiliary factor in base excision repair, resides on 7q22.1, the most frequently and highly amplified chromosomal region in glioblastomas. The resistance of glioblastoma cells to the mono-alkylating agent temozolomide is determined to some extent by the activity of apurinic/apyrimidinic endonuclease 1 (APE1).

Methods

To monitor the effect of CUX1 and its CUT domains on APE1 activity, DNA repair assays were performed with purified proteins and cell extracts. CUX1 protein expression was analyzed by immunohistochemistry using a tumor microarray of 150 glioblastoma samples. The effect of CUX1 knockdown and overexpression on the resistance of glioblastoma cell lines to temozolomide was investigated.

Results

We show that CUT domains stimulate APE1 activity. In agreement with these findings, CUX1 knockdown causes an increase in the number of abasic sites in genomic DNA and a decrease in APE1 activity as measured in cell extracts. Conversely, ectopic CUX1 expression increases APE1 activity and lowers the number of abasic sites. Having established that CUX1 is expressed at high levels in most glioblastomas, we next show that the resistance of glioblastoma cells to temozolomide and to a combined treatment of temozolomide and ionizing radiation is reduced following CUX1 knockdown, but increased by overexpression of CUX1 or a short protein containing only 2 CUT domains, which is active in DNA repair but devoid of transcriptional activity.

Conclusion

These findings indicate that CUX1 expression level impacts on the response of glioblastoma cells to treatment and identifies the CUT domains as potential therapeutic targets.

CUX2 functions as an oncogene in papillary thyroid cancer

BACKGROUND

In recent years, the incidence of thyroid cancer (TC), the most common endocrine malignancy, has been increasing. Emerging evidence indicates that the CUT/CUX/CDP family of proteins can play an important role in tumor development and progression by regulating many cancer-related functions. However, the molecular functions of CUX2 in TC remain unknown.

METHODS

In this study, we used a series of loss-of-function experiments and Western blot analysis to investigate the function of CUX2 in TC and the mechanisms involved.

RESULTS

Our data revealed that CUX2 expression levels were upregulated in papillary thyroid cancer (PTC). Functionally, CUX2 silencing significantly inhibited PTC cell line (KTC-1 and BCPAP) proliferation, colony formation, migration, invasion, and apoptosis. Furthermore, CUX2 induced epithelial-mesenchymal transition (EMT) and influenced the phosphorylation of AKT and mTOR in the PI3K-AKT-mTOR pathways.

CONCLUSION

In summary, CUX2 may function as a tumor promoter in TC.

Molecular profiling of pancreatic neuroendocrine tumors (pNETS) and the clinical potential

Pancreatic neuroendocrine tumors (pNETs) represent a small part of pancreatic neoplasms, and the knowledge about their indolent clinical course remains a subject of investigation. They occur sporadically or as part of familial cancer syndromes and are classified by WHO in 3 categories. There is ongoing research to understand their molecular profiling and leading mutations. Areas covered: The aim of this review is to clarify the overall aspects of tumorigenesis, to expose the latest developments in understanding the course of the disease and the possible therapeutic implications of these. The review also discusses functional and non-functional pNETs and associated inherited syndromes as well as pNET molecular profiling and its possible guidance in the use of targeted therapy. Expert commentary: In the next decade, a more extensive application of new technologies will help improve quality of life and survival, individualizing treatment protocols and identifying which therapeutic strategy is more suitable for each kind of NET.

Downregulation of miR-374b-5p promotes chemotherapeutic resistance in pancreatic cancer by upregulating multiple anti-apoptotic proteins

Resistance to first-line chemotherapeutic drugs such as gemcitabine contributes to the poor prognosis of patients with pancreatic cancer. MicroRNAs (miRNA) regulate chemoresistance in pancreatic cancer. By analyzing the miRNA sequencing dataset of pancreatic cancer from The Cancer Genome Atlas, it was demonstrated that miR-374b-5p expression was dramatically reduced in pancreatic cancer tissues compared with adjacent normal tissues, as well as decreased in chemoresistant compared with chemosensitive pancreatic carcinoma tissues. The decreased expression of miR-374-5p was associated with poor overall and progression-free survival in patients with pancreatic cancer. Furthermore, increased expression of miR-374b-5p abrogated, while the silencing miR-374b-5p increased the chemoresistance of pancreatic cancer cells to gemcitabine in vitro. Importantly, the upregulation of miR-374b-5p ameliorated the chemoresistance of pancreatic cancer cells to gemcitabine in vivo. It was also demonstrated that miR-374b-5p targeted several anti-apoptotic proteins, including B-cell lymphoma 2, Baculoviral IAP Repeat Containing 3 and X-linked inhibitor of apoptosis in pancreatic cancer cells, which further attenuated chemo-resistance in pancreatic cancer. Therefore, the results of the current study indicate that miR-374b-5p serves as a potential diagnostic marker. It also suggests that miR-374b-5p sensitizes cells to chemotherapy and may be used in combination with chemotherapeutic agents such as gemcitabine to treat patients with pancreatic cancer.

Identification of differentially expressed genes and biological pathways in bladder cancer

The purpose of the present study was to identify key genes and investigate the related molecular mechanisms of bladder cancer (BC) progression. From the Gene Expression Omnibus database, the gene expression dataset GSE7476 was downloaded, which contained 43 BC samples and 12 normal bladder tissues. GSE7476 was analyzed to screen the differentially expressed genes (DEGs). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed for the DEGs using the DAVID database, and a protein-protein interaction (PPI) network was then constructed using Cytoscape software. The results of the GO analysis showed that the upregulated DEGs were significantly enriched in cell division, nucleoplasm and protein binding, while the downregulated DEGs were significantly enriched in ‘extracellular matrix organization’, ‘proteinaceous extracellular matrix’ and ‘heparin binding’. The results of the KEGG pathway analysis showed that the upregulated DEGs were significantly enriched in the ‘cell cycle’, whereas the downregulated DEGs were significantly enriched in ‘complement and coagulation cascades’. JUN, cyclin-dependent kinase 1, FOS, PCNA, TOP2A, CCND1 and CDH1 were found to be hub genes in the PPI network. Sub-networks revealed that these gene were enriched in significant pathways, including the ‘cell cycle’ signaling pathway and ‘PI3K-Akt signaling pathway’. In summary, the present study identified DEGs and key target genes in the progression of BC, providing potential molecular targets and diagnostic biomarkers for the treatment of BC.

BAG3 Overexpression and Cytoprotective Autophagy Mediate Apoptosis Resistance in Chemoresistant Breast Cancer Cells

Target-specific treatment modalities are currently not available for triple-negative breast cancer (TNBC), and acquired chemotherapy resistance is a primary obstacle for the treatment of these tumors. Here we employed derivatives of BT-549 and MDA-MB-468 TNBC cell lines that were adapted to grow in the presence of either 5-Fluorouracil, Doxorubicin or Docetaxel in an aim to identify molecular pathways involved in the adaptation to drug-induced cell killing. All six drug-adapted BT-549 and MDA-MB-468 cell lines displayed cross resistance to chemotherapy and decreased apoptosis sensitivity. Expression of the anti-apoptotic co-chaperone BAG3 was notably enhanced in two thirds (4/6) of the six resistant lines simultaneously with higher expression of HSP70 in comparison to parental controls. Doxorubicin-resistant BT-549 (BT-549^rDOX²⁰) and 5-Fluorouracil-resistant MDA-MB-468 (MDA-MB-468^r5-FU²⁰⁰⁰) cells were chosen for further analysis with the autophagy inhibitor Bafilomycin A1 and lentiviral depletion of ATG5, indicating that enhanced cytoprotective autophagy partially contributes to increased drug resistance and cell survival. Stable lentiviral BAG3 depletion was associated with a robust down-regulation of Mcl-1, Bcl-2 and Bcl-xL, restoration of drug-induced apoptosis and reduced cell adhesion in these cells, and these death-sensitizing effects could be mimicked with the BAG3/Hsp70 interaction inhibitor YM-1 and by KRIBB11, a selective transcriptional inhibitor of HSF-1. Furthermore, BAG3 depletion was able to revert the EMT-like transcriptional changes observed in BT-549^rDOX²⁰ and MDA-MB-468^r5-FU²⁰⁰⁰ cells. In summary, genetic and pharmacological interference with BAG3 is capable to resensitize TNBC cells to treatment, underscoring its relevance for cell death resistance and as a target to overcome therapy resistance of breast cancer.

Matrine reversed multidrug resistance of breast cancer MCF-7/ADR cells through PI3K/AKT signaling pathway

Matrine is an alkaloid extracted from a Chinese herb Sophora flavescens Ait, and has been used clinically for breast cancer with marked therapeutic efficacy in China. However, the mechanism has not been well known. Thus, the present study was to explore whether Matrine reverses multidrug resistance for breast cancer cells through the regulation of PI3K/AKT signaling pathway. Methyl thiazolyl tetrazolium (MTT) assay was used to detect the inhibitory action; Annexin V to detect apoptosis; fluorospectrophotometry to examine intracellular adriamycin (ADR) accumulation; and Western blot to label the proteins of P-glycoprotein (P-gp), MRP1, PTEN, p-AKT, Bcl-2, Bax, and Caspase-3. Matrine (0-2.5 mg/mL) inhibited MCF-7/ADR cell growth and induced apoptosis (P < 0.01). A total of 0.2 mg/mL Matrine could increase the intracellular concentration of ADR; the accumulation in MCF-7/ADR cells increased 3.56 times. Compared with control group, 0.6, 1.2 mg/mL Matrine reduced protein expressions of P-gp, MRP1, p-AKT, Bcl-2, but increased PTEN, Bax, and cleaved caspase-3 gradually, and unchanged caspase-3. Matrine was more likely to reduce the expression of P-gp, MRP1, and p-AKT at the same inhibition radio of Matrine, (0.6 mg/mL) and MK2206 (0.05 μmol/L). Matrine inhibited MCF-7/ADR cell growth, induced apoptosis, and reversed multidrug resistance for breast cancer cells through the regulation of downstream apoptosis factors of PI3K/AKT signaling pathway by decreasing cell phosphorylation of AKT level.

Global view of a drug-sensitivity gene network

An important challenge in drug development is to gain insight into the mechanism of drug sensitivity. Looking for insights into the global relationships between drugs and their sensitivity genes would be expected to reveal mechanism of drug sensitivity. Here we constructed a drug-sensitivity gene network (DSGN) based on the relationships between drugs and their sensitivity genes, using drug screened genomic data from the NCI-60 cell line panel, including 181 drugs and 1057 sensitivity genes, and 1646 associations between them. Through network analysis, we found that two drugs that share the same sensitivity genes tend to share the same Anatomical Therapeutic Chemical classification and side effects. We then found that the sensitivity genes of same drugs tend to cluster together in the human interactome and participate in the same biological function modules (pathways). Finally, we noticed that the sensitivity genes and target genes of the same drug have a significant dense distance in the human interactome network and they were functionally related. For example, target genes such as epidermal growth factor receptor gene can activate downstream sensitivity genes of the same drug in the PI3K/Akt pathway. Thus, the DSGN would provide great insights into the mechanism of drug sensitivity.

The DNA repair function of CUX1 contributes to radioresistance

Ionizing radiation generates a broad spectrum of oxidative DNA lesions, including oxidized base products, abasic sites, single-strand breaks and double-strand breaks. The CUX1 protein was recently shown to function as an auxiliary factor that stimulates enzymatic activities of OGG1 through its CUT domains. In the present study, we investigated the requirement for CUX1 and OGG1 in the resistance to radiation. Cancer cell survival following ionizing radiation is reduced by CUX1 knockdown and increased by higher CUX1 expression. However, CUX1 knockdown is sufficient by itself to reduce viability in many cancer cell lines that exhibit high levels of reactive oxygen species (ROS). Consequently, clonogenic results expressed relative to that of non-irradiated cells indicate that CUX1 knockdown confers no or modest radiosensitivity to cancer cells with high ROS. A recombinant protein containing only two CUT domains is sufficient for rapid recruitment to DNA damage, acceleration of DNA repair and increased survival following radiation. In agreement with these findings, OGG1 knockdown and treatment of cells with OGG1 inhibitors sensitize cancer cells to radiation. Together, these results validate CUX1 and more specifically the CUT domains as therapeutic targets.

Dermokine contributes to epithelial-mesenchymal transition through increased activation of signal transducer and activator of transcription 3 in pancreatic cancer

Dermokine (DMKN) was first identified in relation to skin lesion healing and skin carcinoma. Recently, its expression was associated with pancreatic cancer tumorigenesis, although its involvement remains poorly understood. Herein, we showed that DMKN loss of function in Patu‐8988 and PANC‐1 pancreatic cancer cell lines resulted in reduced phosphorylation of signal transducer and activator of transcription 3, and increased activation of ERK1/2 and AKT serine/threonine kinase. This decreased the proliferation ability of pancreatic ductal adenocarcinoma (PDAC) cells. In addition, DMKN knockdown decreased the invasion and migration of PDAC cells, partially reversed the epithelial–mesenchymal transition, retarded tumor growth in a xenograft animal model by decreasing the density of microvessels, and attenuated the distant metastasis of human PDAC in a mouse model. Taken together, these data suggested that DMKN could be a potential prognostic biomarker and therapeutic target in pancreatic cancer.

MicroRNA-330-3p promotes cell invasion and metastasis in non-small cell lung cancer through GRIA3 by activating MAPK/ERK signaling pathway

Background

Brain metastasis (BM) is associated with poor prognosis in patients with non-small cell lung cancer (NSCLC). Recent studies demonstrated that microRNA-330-3p (miR-330-3p) was involved in NSCLC brain metastasis (BM). However, the exact parts played by miR-330-3p in BM of NSCLC remain unknown. Discovery and development of biomarkers and elucidation of the mechanism underlying BM in NSCLC is critical for effective prophylactic interventions. Here, we evaluated the expression and biological effects of miR-330-3p in NSCLC cells and explored the underlying mechanism of miR-330-3p in promoting cell migration and invasion in NSCLC.

Methods

Stable over-expression and knockdown of miR-330-3p in NSCLC cells was constructed with lentivirus. Expression levels of miR-330-3p in NSCLC cells were quantified by quantitive real-time PCR (qRT-PCR). The effects of miR-330-3p on NSCLC cells were investigated using assays of cell viability, migration, invasion, cell cycle, apoptosis, western blotting, immunohistochemical, and immunofluorescence staining. A xenograft nude mouse model and in situ brain metastasis model were used to observe tumor growth and brain metastasis. The potential target of miR-330-3p in NSCLC cells was explored using the luciferase reporter assay, qRT-PCR, and western blotting. The miR-330-3p targets were identified using bioinformatics analysis and verified by luciferase reporter assay. The correlation between GRIA3 and DNA methyltransferase (DNMT) 1 and DNMT3A was tested by RT-PCR, western blotting, and co-immunoprecipitation (IP).

Results

miR-330-3p was significantly up-regulated in NSCLC cell lines. MTT assay, transwell migration, and invasion assays showed that miR-330-3p promoted the growth, migration, and invasion of NSCLC cells in vitro and induced tumor growth and metastasis in vivo. Luciferase reporter assays showed that GRIA3 was a target of miR-330-3p. qRT-PCR and western blotting exhibited that miR-330-3p promoted the growth, invasion, and migration of NSCLC cells by activating mitogen-activated protein kinase (MAPK)/extracellular-regulated protein kinases (ERK) signaling pathway. Furthermore, miR-330-3p up-regulated the total DNA methylation in NSCLC cells, and co-IP-demonstrated GRIA3 was directly related with DNMT1 and DNMT3A.

Conclusions

miR-330-3p promoted the progression of NSCLC and might be a potential target for the further research of NSCLC brain metastasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13045-017-0493-0) contains supplementary material, which is available to authorized users.

miRNA dynamics in tumor-infiltrating myeloid cells modulating tumor progression in pancreatic cancer

Myeloid cells including tumor-associated macrophages (TAM) and myeloid-derived suppressor cells (MDSC) are known as important mediators of tumor progression in solid tumors such as pancreatic cancer. Infiltrating myeloid cells have been identified not only in invasive tumors, but also in early pre-invasive pancreatic intraepithelial precursor lesions (PanIN). The functional dynamics of myeloid cells during carcinogenesis is largely unknown. We aimed to systematically elucidate phenotypic and transcriptional changes in infiltrating myeloid cells during carcinogenesis and tumor progression in a genetic mouse model of pancreatic cancer. Using murine pancreatic myeloid cells isolated from the genetic mouse model at different time points during carcinogenesis, we examined both established markers of macrophage polarization using RT-PCR and FACS as well as transcriptional changes focusing on miRNA profiling. Myeloid cells isolated during carcinogenesis showed a simultaneous increase of established markers of M1 and M2 polarization during carcinogenesis, indicating that phenotypic changes of myeloid cells during carcinogenesis do not follow the established M1/M2 classification. MiRNA profiling revealed distinct regulations of several miRNAs already present in myeloid cells infiltrating pre-invasive PanIN lesions. Among them miRNA-21 was significantly increased in myeloid cells surrounding both PanIN lesions and invasive cancers. Functionally, miRNA-21-5p and -3p altered expression of the immune-modulating cytokines CXCL-10 and CCL-3 respectively. Our data indicate that miRNAs are dynamically regulated in infiltrating myeloid cells during carcinogenesis and mediate their functional phenotype by facilitating an immune-suppressive tumor-promoting micro-milieu.

Phosphorylated Ribosomal Protein S6 Is Required for Akt-Driven Hyperplasia and Malignant Transformation, but Not for Hypertrophy, Aneuploidy and Hyperfunction of Pancreatic β-Cells

Constitutive expression of active Akt (Akt^tg) drives hyperplasia and hypertrophy of pancreatic β-cells, concomitantly with increased insulin secretion and improved glucose tolerance, and at a later stage the development of insulinoma. To determine which functions of Akt are mediated by ribosomal protein S6 (rpS6), an Akt effector, we generated mice that express constitutive Akt in β-cells in the background of unphosphorylatable ribosomal protein S6 (rpS6^P-/-). rpS6 phosphorylation deficiency failed to block Akt^tg-induced hypertrophy and aneuploidy in β-cells, as well as the improved glucose homeostasis, indicating that Akt carries out these functions independently of rpS6 phosphorylation. In contrast, rpS6 phosphorylation deficiency efficiently restrained the reduction in nuclear localization of the cell cycle inhibitor p27, as well as the development of Akt^tg-driven hyperplasia and tumor formation in β-cells. In vitro experiments with Akt^tg and rpS6^P-/-;Akt^tg fibroblasts demonstrated that rpS6 phosphorylation deficiency leads to reduced translation fidelity, which might underlie its anti-tumorigenic effect in the pancreas. However, the role of translation infidelity in tumor suppression cannot simply be inferred from this heterologous experimental model, as rpS6 phosphorylation deficiency unexpectedly elevated the resistance of Akt^tg fibroblasts to proteotoxic, genotoxic as well as autophagic stresses. In contrast, rpS6^P-/- fibroblasts exhibited a higher sensitivity to these stresses upon constitutive expression of oncogenic Kras. The latter result provides a possible mechanistic explanation for the ability of rpS6 phosphorylation deficiency to enhance DNA damage and protect mice from Kras-induced neoplastic transformation in the exocrine pancreas. We propose that Akt1 and Kras exert their oncogenic properties through distinct mechanisms, even though both show addiction to rpS6 phosphorylation.

The transcription factor Cux1 in cerebellar granule cell development and medulloblastoma pathogenesis

Cux1, also known as Cutl1, CDP or Cut is a homeodomain transcription factor implicated in the regulation of normal and oncogenic development in diverse peripheral tissues and organs. We studied the expression and functional role of Cux1 in cerebellar granule cells and medulloblastoma. Cux1 is robustly expressed in proliferating granule cell precursors and in postmitotic, migrating granule cells. Expression is lost as postmigratory granule cells mature. Moreover, Cux1 is also strongly expressed in a well-established mouse model of medulloblastoma. In contrast, expression of CUX1 in human medulloblastoma tissue samples is lower than in normal fetal cerebellum. In these tumors, CUX1 expression tightly correlates with a set of genes which, when mapped on a global protein-protein interaction dataset, yields a tight network that constitutes a cell cycle control signature and may be related to p53 and the DNA damage response pathway. Antisense-mediated reduction of CUX1 levels in two human medulloblastoma cell lines led to a decrease in proliferation and altered motility. The developmental expression of Cux1 in the cerebellum and its action in cell lines support a role in granule cell and medulloblastoma proliferation. Its expression in human medulloblastoma shifts that perspective, suggesting that CUX1 is part of a network involved in cell cycle control and maintenance of DNA integrity. The constituents of this network may be rational targets to therapeutically approach medulloblastomas.

Epidemiological and genetic clues for molecular mechanisms involved in uterine leiomyoma development and growth

BACKGROUND

Uterine leiomyomas (fibroids) are highly prevalent benign smooth muscle tumors of the uterus. In the USA, the lifetime risk for women developing uterine leiomyomas is estimated as up to 75%. Except for hysterectomy, most therapies or treatments often provide only partial or temporary relief and are not successful in every patient. There is a clear racial disparity in the disease; African-American women are estimated to be three times more likely to develop uterine leiomyomas and generally develop more severe symptoms. There is also familial clustering between first-degree relatives and twins, and multiple inherited syndromes in which fibroid development occurs. Leiomyomas have been described as clonal and hormonally regulated, but despite the healthcare burden imposed by the disease, the etiology of uterine leiomyomas remains largely unknown. The mechanisms involved in their growth are also essentially unknown, which has contributed to the slow progress in development of effective treatment options.

METHODS

A comprehensive PubMed search for and critical assessment of articles related to the epidemiological, biological and genetic clues for uterine leiomyoma development was performed. The individual functions of some of the best candidate genes are explained to provide more insight into their biological function and to interconnect and organize genes and pathways in one overarching figure that represents the current state of knowledge about uterine leiomyoma development and growth.

RESULTS

In this review, the widely recognized roles of estrogen and progesterone in uterine leiomyoma pathobiology on the basis of clinical and experimental data are presented. This is followed by fundamental aspects and concepts including the possible cellular origin of uterine fibroids. The central themes in the subsequent parts are cytogenetic aberrations in leiomyomas and the racial/ethnic disparities in uterine fibroid biology. Then, the attributes of various in vitro and in vivo, human syndrome, rodent xenograft, naturally mutant, and genetically modified models used to study possible molecular mechanisms of leiomyoma development and growth are described. Particular emphasis is placed on known links to fibrosis, hypertrophy, and hyperplasia and genes that are potentially important in these processes.

CONCLUSIONS

Menstrual cycle-related injury and repair and coinciding hormonal cycling appears to affect myometrial stem cells that, at a certain stage of fibroid development, often obtain cytogenetic aberrations and mutations of Mediator complex subunit 12 (MED12). Mammalian target of rapamycin (mTOR), a master regulator of proliferation, is activated in many of these tumors, possibly by mechanisms that are similar to some human fibrosis syndromes and/or by mutation of upstream tumor suppressor genes. Animal models of the disease support some of these dysregulated pathways in fibroid etiology or pathogenesis, but none are definitive. All of this suggests that there are likely several key mechanisms involved in the disease that, in addition to increasing the complexity of uterine fibroid pathobiology, offer possible approaches for patient-specific therapies. A final model that incorporates many of these reported mechanisms is presented with a discussion of their implications for leiomyoma clinical practice.

Current and future intratumoral targeted treatment for pancreatic cancer

Pancreatic cancer is an insidious type of cancer with its symptoms manifested upon extensive disease. The overall 5-year survival rates between 0.4 and 4%. Surgical resection is an option for only 10% of the patients with pancreatic cancer. Local recurrence and hepatic metastases occur within 2 years after surgery. There are currently several molecular pathways investigated and novel targeted treatments are on the market. However; the nature of pancreatic cancer with its ability to spread locally in the primary site and lymph nodes indicates that further experimentation with local interventional therapies could be a future treatment proposal as palliative care or adjunct to gene therapy and chemotherapy/radiotherapy. In the current review, we will summarize the molecular pathways and present the interventional treatment options for pancreatic cancer.

Human umbilical cord blood cells induce neuroprotective change in gene expression profile in neurons after ischemia through activation of Akt pathway

Human umbilical cord blood (HUCB) cell therapies have shown promising results in reducing brain infarct volume and most importantly in improving neurobehavioral function in rat permanent middle cerebral artery occlusion, a model of stroke. In this study, we examined the gene expression profile in neurons subjected to oxygen-glucose deprivation (OGD) with or without HUCB treatment and identified signaling pathways (Akt/MAPK) important in eliciting HUCB-mediated neuroprotective responses. Gene chip microarray analysis was performed using RNA samples extracted from the neuronal cell cultures from four experimental groups: normoxia, normoxia+HUCB, OGD, and OGD+HUCB. Both quantitative RT-PCR and immunohistochemistry were carried out to verify the microarray results. Using the Genomatix software program, promoter regions of selected genes were compared to reveal common transcription factor-binding sites and, subsequently, signal transduction pathways. Under OGD condition, HUCB cells significantly reduced neuronal loss from 68% to 44% [one-way ANOVA, F(3, 16)=11, p=0.0003]. Microarray analysis identified mRNA expression of Prdx5, Vcam1, CCL20, Alcam, and Pax6 as being significantly altered by HUCB cell treatment. Inhibition of the Akt pathway significantly abolished the neuroprotective effect of HUCB cells [one-way ANOVA, F(3, 11)=8.663, p=0.0031]. Our observations show that HUCB neuroprotection is dependent on the activation of the Akt signaling pathway that increases transcription of the Prdx5 gene. We concluded that HUCB cell therapy would be a promising treatment for stroke and other forms of brain injury by modifying acute gene expression to promote neural cell protection.

CUX1, a haploinsufficient tumour suppressor gene overexpressed in advanced cancers

CUT-like homeobox 1 (CUX1) is a homeobox gene that is implicated in both tumour suppression and progression. The accumulated evidence supports a model of haploinsufficiency whereby reduced CUX1 expression promotes tumour development. Paradoxically, increased CUX1 expression is associated with tumour progression, and ectopic CUX1 expression in transgenic mice increases tumour burden in several tissues. One CUX1 isoform functions as an ancillary factor in base excision repair and the other CUX1 isoforms act as transcriptional activators or repressors. Several transcriptional targets and cellular functions of CUX1 affect tumorigenesis; however, we have yet to develop a mechanistic framework to reconcile the opposite roles of CUX1 in cancer protection and progression.

Autocrine Activation of the Wnt/β-Catenin Pathway by CUX1 and GLIS1 in Breast Cancers

Autocrine activation of the Wnt/β-catenin pathway occurs in several cancers, notably in breast tumors, and is associated with higher expression of various Wnt ligands. Using various inhibitors of the FZD/LRP receptor complex, we demonstrate that some adenosquamous carcinomas that develop in MMTV-CUX1 transgenic mice represent a model for autocrine activation of the Wnt/β-catenin pathway. By comparing expression profiles of laser-capture microdissected mammary tumors, we identify Glis1 as a transcription factor that is highly expressed in the subset of tumors with elevated Wnt gene expression. Analysis of human cancer datasets confirms that elevated WNT gene expression is associated with high levels of CUX1 and GLIS1 and correlates with genes of the epithelial-to-mesenchymal transition (EMT) signature: VIM, SNAI1 and TWIST1 are elevated whereas CDH1 and OCLN are decreased. Co-expression experiments demonstrate that CUX1 and GLIS1 cooperate to stimulate TCF/β-catenin transcriptional activity and to enhance cell migration and invasion. Altogether, these results provide additional evidence for the role of GLIS1 in reprogramming gene expression and suggest a hierarchical model for transcriptional regulation of the Wnt/β-catenin pathway and the epithelial-to-mesenchymal transition.