A novel cell-penetrating peptide suppresses breast tumorigenesis by inhibiting beta-catenin/LEF-1 signaling. Sci Rep. 2016;6:19156. [PMID: 26750754 PMCID: PMC4707489 DOI: 10.1038/srep19156]

Wnt/β-catenin signalling, epithelial-mesenchymal transition and crosslink signalling in colorectal cancer cells

Colorectal cancer (CRC), with its significant incidence and metastatic rates, profoundly affects human health. A common oncogenic event in CRC is the aberrant activation of the Wnt/β-catenin signalling pathway, which drives both the initiation and progression of the disease. Persistent Wnt/β-catenin signalling facilitates the epithelial-mesenchymal transition (EMT), which accelerates CRC invasion and metastasis. This review provides a summary of recent molecular studies on the role of the Wnt/β-catenin signalling axis in regulating EMT in CRC cells, which triggers metastatic pathogenesis. We present a comprehensive examination of the EMT process and its transcriptional controllers, with an emphasis on the crucial functions of β-catenin, EMT transcription factors (EMT-TFs). We also review recent evidences showing that hyperactive Wnt/β-catenin signalling triggers EMT and metastatic phenotypes in CRC via "Destruction complex" of β-catenin mechanisms. Potential therapeutic and challenges approache to suppress EMT and prevent CRC cells metastasis by targeting Wnt/β-catenin signalling are also discussed. These include direct β-catenin inhibitors and novel targets of the Wnt pathway, and finally highlight novel potential combinational treatment options based on the inhibition of the Wnt pathway.

Role of sodium/iodide symporter overexpression in inhibiting thyroid cancer cell invasion and stem cell maintenance by inhibiting the β-catenin/LEF-1 pathway

Background

In thyroid cancers, a reduction in the expression of the sodium/iodide symporter (NIS) is observed concomitant with a diminution in cancer cell differentiation. The β-catenin/LEF-1 pathway emerges as a crucial regulatory pathway influencing the functional expression of NIS in human thyroid cancer cells. Further research is required to comprehensively elucidate the role of NIS overexpression in impeding the progression of thyroid cancer cells.

Methods

Human papillary thyroid carcinoma (PTC) cell lines, specifically PTC-1 and KTC-1, were subjected to Scratch and Transwell assays, colony formation, and tumor sphere formation tests to investigate invasion and migration, focusing on the impact of NIS overexpression. The assessment involved the use of western blot to analyze the expression levels of β-catenin, NIS, CD133, SRY-related HMG box2 (Sox2), lymphoid enhancer-binding factor 1 (LEF-1), NANOG, octamer-binding transcription factor 4 (Oct4), aldehyde dehydrogenase 1 family, member A1 (ALDH1A1), and epithelial cellular adhesion molecule (EpCAM). Statistical analysis was conducted using SPSS version 20.0, and the graphs were developed using GraphPad Prism 7 (GraphPad Software, Inc.).

Results

Our observations revealed that Nthy-ori-3-1 cell lines exhibited notably higher average expression levels of NIS, yet significantly lower levels of LEF-1 and β-catenin compared to PTC-1 and KTC-1 cell lines. Furthermore, the overexpression of β-catenin resulted in reduced binding of LEF-1 to NIF promotion but concurrently increased the expression of NIS. The downregulation of NIS markedly enhanced the expression of ALDH1A1, CD133, OCT4, Nanog, SOX2, and EpCam-all of which are targets within the Wnt/β-catenin signaling pathway. Conversely, the upregulation of NIS suppressed the expression of these proteins. Moreover, cells treated with β-catenin activators demonstrated an increased capability to form more spheroids and displayed heightened aggressiveness. Conversely, the NIS overexpression (OE) group exhibited suppressed abilities in invasion and colony formation.

Conclusion

Thyroid cancer cells exhibit diminished expression of NIS, and the invasion and maintenance of stem cells in thyroid cancer cells were hindered by NIS OE through the inhibition of the β-catenin/LEF-1 pathway. Further research is warranted to comprehensively assess this outcome, which holds promise as a potential targeted treatment for thyroid cancer.

Peptide Regulation of Chondrogenic Stem Cell Differentiation

The search for innovative ways to treat osteoarthritis (OA) is an urgent task for molecular medicine and biogerontology. OA leads to disability in persons of middle and older age, while safe and effective methods of treating OA have not yet been discovered. The directed differentiation of mesenchymal stem cells (MSCs) into chondrocytes is considered one of the possible methods to treat OA. This review describes the main molecules involved in the chondrogenic differentiation of MSCs. The peptides synthesized on the basis of growth factors' structures (SK2.1, BMP, B2A, and SSPEPS) and components of the extracellular matrix of cartilage tissue (LPP, CFOGER, CMP, RDG, and N-cadherin mimetic peptide) offer the greatest promise for the regulation of the chondrogenic differentiation of MSCs. These peptides regulate the WNT, ERK-p38, and Smad 1/5/8 signaling pathways, gene expression, and the synthesis of chondrogenic differentiation proteins such as COL2, SOX9, ACAN, etc.

What Zebrafish and Nanotechnology Can Offer for Cancer Treatments in the Age of Personalized Medicine

Cancer causes millions of deaths each year and thus urgently requires the development of new therapeutic strategies. Nanotechnology-based anticancer therapies are a promising approach, with several formulations already approved and in clinical use. The evaluation of these therapies requires efficient in vivo models to study their behavior and interaction with cancer cells, and to optimize their properties to ensure maximum efficacy and safety. In this way, zebrafish is an important candidate due to its high homology with the human genoma, its large offspring, and the ease in developing specific cancer models. The role of zebrafish as a model for anticancer therapy studies has been highly evidenced, allowing researchers not only to perform drug screenings but also to evaluate novel therapies such as immunotherapies and nanotherapies. Beyond that, zebrafish can be used as an “avatar” model for performing patient-derived xenografts for personalized medicine. These characteristics place zebrafish in an attractive position as a role model for evaluating novel therapies for cancer treatment, such as nanomedicine.

Natural products targeting cancer cell dependency

Precision cancer medicine is a tailored treatment approach for individual cancer patients with different genomic characteristics. Mutated or hyperactive oncogenes have served as main drug targets in current precision cancer medicine, while defective or inactivated tumor suppressors in general have not been considered as druggable targets. Synthetic lethality is one of very few approaches that enable to target defective tumor suppressors with pharmacological agents. Synthetic lethality exploits cancer cell dependency on a protein or pathway, which arises when the function of a tumor suppressor is defective. This approach has been proven to be effective in clinical settings since the successful clinical introduction of BRCA-PARP synthetic lethality for the treatment of breast and ovarian cancer with defective BRCA. Subsequently, large-scale screenings with RNAi, CRISPR/Cas9-sgRNAs, and chemical libraries have been applied to identify synthetic lethal partners of tumor suppressors. Natural products are an important source for the discovery of pharmacologically active small molecules. However, little effort has been made in the discovery of synthetic lethal small molecules from natural products. This review introduces recent advances in the discovery of natural products targeting cancer cell dependency and discusses potentials of natural products in the precision cancer medicine.

Lef-1 controls cell cycle progression in airway basal cells to regulate proliferation and differentiation

The mammalian airways are lined by a continuous epithelial layer that is maintained by diverse populations of resident multipotent stem cells. These stem cells are responsible for replenishing the epithelium both at homeostasis and following injury, making them promising targets for stem cell and genetic-based therapies for a variety of respiratory diseases. However, the mechanisms that regulate when and how these stem cells proliferate, migrate, and differentiate remains incompletely understood. Here, we find that the high mobility group (HMG) domain transcription factor Lef-1 regulates proliferation and differentiation of mouse tracheal basal cells. We demonstrate that conditional deletion of Lef-1 stalls basal cell proliferation at the G1/S transition of the cell cycle, and that Lef-1 knockout cells are unable to maintain luminal tracheal cell types in long-term air-liquid interface culture. RNA sequencing analysis revealed that Lef-1 knockout (Lef-1KO) results in downregulation of key DNA damage response and cell cycle progression genes, including the kinase Chek1. Furthermore, chemical inhibition of Chek1 is sufficient to stall basal cell self-renewal in a similar fashion as Lef-1 deletion. Notably, the cell cycle block imposed by Lef-1KO in vitro is transient and basal cells eventually compensate to proliferate normally in a Chek1-independent manner. Finally, Lef-1KO cells were unable to fully regenerate tracheal epithelium following injury in vivo. These findings reveal that Lef-1 is essential for proper basal cell function. Thus, modulating Lef-1 function in airway basal cells may have applications in regenerative medicine.

Biomedical Relevance of Novel Anticancer Peptides in the Sensitive Treatment of Cancer

The global increase in cancer mortality and economic losses necessitates the cautious quest for therapeutic agents with compensatory advantages over conventional therapies. Anticancer peptides (ACPs) are a subset of host defense peptides, also known as antimicrobial peptides, which have emerged as therapeutic and diagnostic candidates due to several compensatory advantages over the non-specificity of the current treatment regimens. This review aimed to highlight the ravaging incidence of cancer, the use of ACPs in cancer treatment with their mechanisms, ACP discovery and delivery methods, and the limitations for their use. This would create awareness for identifying more ACPs with better specificity, accuracy and sensitivity towards the disease. It would also promote their efficacious utilization in biotechnology, medical sciences and molecular biology to ease the severity of the disease and enable the patients living with these conditions to develop an accommodating lifestyle.

Bicyclic β-Sheet Mimetics that Target the Transcriptional Coactivator β-Catenin and Inhibit Wnt Signaling

Protein complexes are defined by the three-dimensional structure of participating binding partners. Knowledge about these structures can facilitate the design of peptidomimetics which have been applied for example, as inhibitors of protein-protein interactions (PPIs). Even though β-sheets participate widely in PPIs, they have only rarely served as the basis for peptidomimetic PPI inhibitors, in particular when addressing intracellular targets. Here, we present the structure-based design of β-sheet mimetics targeting the intracellular protein β-catenin, a central component of the Wnt signaling pathway. Based on a protein binding partner of β-catenin, a macrocyclic peptide was designed and its crystal structure in complex with β-catenin obtained. Using this structure, we designed a library of bicyclic β-sheet mimetics employing a late-stage diversification strategy. Several mimetics were identified that compete with transcription factor binding to β-catenin and inhibit Wnt signaling in cells. The presented design strategy can support the development of inhibitors for other β-sheet-mediated PPIs.

The Role of IL-9 Polymorphisms and Serum IL-9 Levels in Carcinogenesis and Survival Rate for Laryngeal Squamous Cell Carcinoma

Recent studies have described the dichotomous function of IL-9 in various cancer diseases. However, its function has still not been analysed in laryngeal squamous cell carcinoma (LSCC). In the present study, we evaluated five single nucleotide polymorphisms (SNPs) of IL-9 (rs1859430, rs2069870, rs11741137, rs2069885, and rs2069884) and determined their associations with the patients' five-year survival rate. Additionally, we analysed serum IL-9 levels using an enzyme-linked immunosorbent assay. Three hundred LSCC patients and 533 control subjects were included in this study. A significant association between the patients' survival rate and distribution of IL-9 rs1859430 variants was revealed: patients carrying AA genotype had a higher risk of dying (p = 0.005). Haplotypes A-G-C-G-G of IL-9 (rs1859430, rs2069870, rs11741137, rs2069885, and rs2069884) were associated with 47% lower odds of LSCC occurrence (p = 0.035). Serum IL-9 levels were found detectable in three control group subjects (8.99 ± 12.03 pg/mL). In summary, these findings indicate that the genotypic distribution of IL-9 rs1859430 negatively influences the five-year survival rate of LSCC patients. The haplotypes A-G-C-G-G of IL-9 (rs1859430, rs2069870, rs11741137, rs2069885, and rs2069884) are associated with the lower odds of LSCC development.

Targeting Oncogenic WNT Signalling with WNT Signalling-Derived Peptides

WNT signalling is known to be a crucial regulator of embryonic development and tissue homeostasis. Aberrant expression of WNT signalling elements or their mutations has been implicated in carcinogenesis and/or the progression of several different cancer types. Investigations of how WNT signalling affects carcinogenesis and cancer progression have revealed that it has essential roles in the regulation of proliferation, apoptosis, and cancer stemness and in angiogenesis and metastasis. Consequently, WNT-targeted therapy has gained much attention and has resulted in the development of several small molecules, the majority of which act as inhibitors of different WNT signalling events. However, although numerous inhibitory WNT signalling drug candidates have been included in clinical trials, no significant breakthroughs have been made. This could possibly be due to problems with inefficient binding to the target, compensatory signalling mechanisms and toxicity towards normal cells. Therapeutic peptides targeting WNT signalling in cancer cells have been developed as an alternative approach, with the hope that they might overcome the limitations reported for small WNT inhibitory molecules. In this chapter, we describe recent developments made in the design and characterization of WNT signalling-derived peptides aiming at their use as alternative cancer therapeutics and/or combined adjuvant therapy to conventional therapies.

Intratumoral interleukin-9 delineates a distinct immunogenic class of gastric cancer patients with better prognosis and adjuvant chemotherapeutic response

Interleukin-9 (IL-9) is a T cell cytokine that is associated with inflammation and allergy, but the expression level of IL-9 in gastric cancer and its clinical significance are less well established. Our study aims to uncover the critical role of IL-9 in the progression of gastric cancer. Here, a total of 453 patients with gastric cancer undergoing curative resection were enrolled for immunohistochemical analyses, and Kaplan-Meier analysis was conducted to compare overall survival of patients in different subgroups. We further investigated the correlation between IL-9 expression and functional status of intratumoral CD8⁺ T cells by means of Flow cytometry. Moreover, in vitro study was preformed to further explore the influence of IL-9 on anti-tumor immunity. Results indicated that gastric cancer patients with high IL-9 expression showed improved overall survival and gained more benefit from 5-fluorouracil-based adjuvant chemotherapy (ACT). High IL-9 expression was associated with increased numbers and elevated function of intratumoral CD8⁺ T cells. In vitro study revealed that recombinant human IL-9 (rhIL-9) exhibit anti-tumor activity via enhancing the function of intratumoral CD8⁺ T cells. Moreover, we found rhIL-9 could augment the efficacy of Pembrolizumab in gastric cancer. In summary, these results suggest that IL-9 expression could act as an independent predictor for overall survival and ACT response and enhancing IL-9 signaling might represent an important therapeutic strategy in gastric cancer.

A Synthetic CPP33-Conjugated HOXA9 Active Domain Peptide Inhibits Invasion Ability of Non-Small Lung Cancer Cells

Homeobox A9 (HOXA9) expression is associated with the aggressive growth of cancer cells and poor prognosis in lung cancer. Previously, we showed that HOXA9 can serve as a potential therapeutic target for the treatment of metastatic non-small cell lung cancer (NSCLC). In the present study, we have carried out additional studies toward the development of a peptide-based therapeutic agent. Vectors expressing partial DNA fragments of HOXA9 were used to identify a unique domain involved in the inhibition of NSCLC cell invasion. Next, we performed in vitro invasion assays and examined the expression of EMT-related genes in transfected NSCLC cells. The C-terminal fragment (HOXA9-C) of HOXA9 inhibited cell invasion and led to upregulation of CDH1 and downregulation of SNAI2 in A549 and NCI-H1299 cells. Reduced SNAI2 expression was consistent with the decreased binding of transcription factor NF-kB to the SNAI2 promoter region in HOXA9-C overexpressing cells. Based on the above results, we synthesized a cell-permeable peptide, CPP33-HADP (HOXA9 active domain peptide), for lung-specific delivery and tested its therapeutic efficiency. CPP33-HADP effectively reduced the invasion ability of NSCLC cells in both in vitro and in vivo mouse models. Our results suggest that CPP33-HADP has significant potential for therapeutic applications in metastatic NSCLC.

Optimizations of a novel fluorescence polarization-based high-throughput screening assay for β-catenin/LEF1 interaction inhibitors

Aberrant activation of the Wnt/β-catenin signaling pathway is prominent in the development and metastasis of non-small cell lung cancer (NSCLC). Highly effective inhibition of this pathway highlights a therapeutic avenue against NSCLC. Moreover, β-catenin/LEF1 interaction regulates β-catenin nuclear transport as well as the transcriptions of the key oncogenes in Wnt/β-catenin signaling pathway. Therefore, interruption of this interaction would be a promising therapeutic strategy for NSCLC metastasis. To date, no economical and rapid high-throughput screening (HTS) assay has been reported for the discovery of β-catenin/LEF1 interaction inhibitors. In this study, we developed a novel fluorescence polarization (FP)-based HTS assay to identify β-catenin/LEF1 interaction inhibitors. The FITC-LEF1 sequence, incubation time, temperature, and DMSO resistance were optimized, and then a high Z' factor of 0.77 was achieved. A pilot screening of a natural product library via this established FP screening assay identified sanguinarine analogues as potential β-catenin/LEF1 interaction inhibitors. GST pull-down and surface plasmon resonance (SPR) assay demonstrated that β-catenin/LEF1 interaction is a potential anticancer target of sanguinarine in vitro. This newly developed FP screening assay will be vital for the rapid discovery of novel Wnt inhibitors targeting β-catenin/LEF1 interaction.

Interleukin-9 Inhibits Lung Metastasis of Melanoma through Stimulating Anti-Tumor M1 Macrophages

Interleukin-9 (IL-9) is well known for its role in allergic inflammation. For cancer, both pro- and anti-tumor effects of IL-9 were controversially reported, but the impact of IL-9 on tumor metastasis has not yet been clarified. In this study, IL-9 was expressed as a secretory form (sIL-9) and a membrane-bound form (mbIL-9) on B16F10 melanoma cells. The mbIL-9 was engineered as a chimeric protein with the transmembrane and cytoplasmic region of TNF-α. The effect of either mbIL-9 or sIL-9 expressing cells were analyzed on the metastasis capability of the cancer cells. After three weeks of tumor implantation into C57BL/6 mice through the tail vein, the number of tumor modules in lungs injected with IL-9 expressing B16F10 was 5-fold less than that of control groups. The percentages of CD4+ T cells, CD8+ T cells, NK cells, and M1 macrophages considerably increased in the lungs of the mice injected with IL-9 expressing cells. Among them, the M1 macrophage subset was the most significantly enhanced. Furthermore, peritoneal macrophages, which were stimulated with either sIL-9 or mbIL-9 expressing transfectant, exerted higher anti-tumor cytotoxicity compared with that of the mock control. The IL-9-stimulated peritoneal macrophages were highly polarized to M1 phenotype. Stimulation of RAW264.7 macrophages with sIL-9 or mbIL-9 expressing cells also significantly increased the cytotoxicity of those macrophages against wild-type B16F10 cells. These results clearly demonstrate that IL-9 can induce an anti-metastasis effect by enhancing the polarization and proliferation of M1 macrophages.

Zebrafish Xenografts for Drug Discovery and Personalized Medicine

Cancer is the second leading cause of death in the world. Given that cancer is a highly individualized disease, predicting the best chemotherapeutic treatment for individual patients can be difficult. Ex vivo models such as mouse patient-derived xenografts (PDX) and organoids are being developed to predict patient-specific chemosensitivity profiles before treatment in the clinic. Although promising, these models have significant disadvantages including long growth times that introduce genetic and epigenetic changes to the tumor. The zebrafish xenograft assay is ideal for personalized medicine. Imaging of the small, transparent fry is unparalleled among vertebrate organisms. In addition, the speed (5-7 days) and small patient tissue requirements (100-200 cells per animal) are unique features of the zebrafish xenograft model that enable patient-specific chemosensitivity analyses.

The Th9 Axis Reduces the Oxidative Stress and Promotes the Survival of Malignant T Cells in Cutaneous T-Cell Lymphoma Patients

Immune dysfunction is critical in pathogenesis of cutaneous T-cell lymphoma (CTCL). Few studies have reported abnormal cytokine profile and dysregulated T-cell functions during the onset and progression of certain types of lymphoma. However, the presence of IL9-producing Th9 cells and their role in tumor cell metabolism and survival remain unexplored. With this clinical study, we performed multidimensional blood endotyping of CTCL patients before and after standard photo/chemotherapy and revealed distinct immune hallmarks of the disease. Importantly, there was a higher frequency of "skin homing" Th9 cells in CTCL patients with early (T1 and T2) and advanced-stage disease (T3 and T4). However, advanced-stage CTCL patients had severely impaired frequency of skin-homing Th1 and Th17 cells, indicating attenuated immunity. Treatment of CTCL patients with standard photo/chemotherapy decreased the skin-homing Th9 cells and increased the Th1 and Th17 cells. Interestingly, T cells of CTCL patients express IL9 receptor (IL9R), and there was negligible IL9R expression on T cells of healthy donors. Mechanistically, IL9/IL9R interaction on CD3⁺ T cells of CTCL patients and Jurkat cells reduced oxidative stress, lactic acidosis, and apoptosis and ultimately increased their survival. In conclusion, coexpression of IL9 and IL9R on T cells in CTCL patients indicates the autocrine-positive feedback loop of Th9 axis in promoting the survival of malignant T cells by reducing the oxidative stress. IMPLICATIONS: The critical role of Th9 axis in CTCL pathogenesis indicates that strategies targeting Th9 cells might harbor significant potential in developing robust CTCL therapy.

Research Progress Evaluating the Function and Mechanism of Anti-Tumor Peptides

Malignant tumors cause a high mortality rate worldwide, and they severely threaten human health and negatively affect the economy. Despite the advancements in tumor-related molecular genetics and effective new processes in anti-tumor drug development, the anti-tumor drugs currently used in clinical practice are inadequate due to their poor efficacy or severe side effects. Therefore, developing new safe and efficient drugs is a top priority for curing cancer. The peptide has become a suitable agent due to its exact molecular weight between whole protein and small molecule, and it has high targeting ability, high penetrability, low immunogenicity, and is convenient to synthesize and easy to modify. Because of these advantages, peptides have excellent prospect for application as anti-tumor agents. This article reviews the recent research progress evaluating anti-tumor peptides and their anti-tumor mechanisms, and may act as a reference for the future development and clinical application of anti-tumor peptides.

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An engineered antibody fragment targeting mutant β-catenin via major histocompatibility complex I neoantigen presentation

Mutations in CTNNB1, the gene encoding β-catenin, are common in colon and liver cancers, the most frequent mutation affecting Ser-45 in β-catenin. Peptides derived from WT β-catenin have previously been shown to be presented on the cell surface as part of major histocompatibility complex (MHC) class I, suggesting an opportunity for targeting this common driver gene mutation with antibody-based therapies. Here, crystal structures of both the WT and S45F mutant peptide bound to HLA-A*03:01 at 2.20 and 2.45 Å resolutions, respectively, confirmed the accessibility of the phenylalanine residue for antibody recognition. Phage display was then used to identify single-chain variable fragment clones that selectively bind the S45F mutant peptide presented in HLA-A*03:01 and have minimal WT or other off-target binding. Following the initial characterization of five clones, we selected a single clone, E10, for further investigation. We developed a computational model of the binding of E10 to the mutant peptide-bound HLA-A3, incorporating data from affinity maturation as initial validation. In the future, our model may be used to design clones with maintained specificity and higher affinity. Such derivatives could be adapted into either cell-based (CAR-T) or protein-based (bispecific T-cell engagers) therapies to target cancer cells harboring the S45F mutation in CTNNB1.

Smart Targeting To Improve Cancer Therapeutics

Cancer is the second largest cause of death worldwide with the number of new cancer cases predicted to grow significantly in the next decades. Biotechnology and medicine can and should work hand-in-hand to improve cancer diagnosis and treatment efficacy. However, success has been frequently limited, in particular when treating late-stage solid tumors. There still is the need to develop smart and synergistic therapeutic approaches to achieve the synthesis of strong and effective drugs and delivery systems. Much interest has been paid to the development of smart drug delivery systems (drug-loaded particles) that utilize passive targeting, active targeting, and/or stimulus responsiveness strategies. This review will summarize some main ideas about the effect of each strategy and how the combination of some or all of them has shown to be effective. After a brief introduction of current cancer therapies and their limitations, we describe the biological barriers that nanoparticles need to overcome, followed by presenting different types of drug delivery systems to improve drug accumulation in tumors. Then, we describe cancer cell membrane targets that increase cellular drug uptake through active targeting mechanisms. Stimulus-responsive targeting is also discussed by looking at the intra- and extracellular conditions for specific drug release. We include a significant amount of information summarized in tables and figures on nanoparticle-based therapeutics, PEGylated drugs, different ligands for the design of active-targeted systems, and targeting of different organs. We also discuss some still prevailing fundamental limitations of these approaches, eg, by occlusion of targeting ligands.

N-arylpiperazine-containing compound (C2): An enhancer of sunitinib in the treatment of pancreatic cancer, involving D1DR activation

Previous studies showed that dopamine (DA) significantly reduces the frequency of cancer stem-like cells (CSC) and enhances the efficacy of sunitinib (SUN) in the treatment of breast cancer and non-small cell lung cancer (NSCLC). To overcome the shortcomings of DA in clinical practice, the purpose of this study was to investigate the efficacy as well as the underlying mechanism of an orally available, N-arylpiperazine-containing compound C2, in the treatment of pancreatic cancer when used alone or in combination with SUN. Our results showed that C2 and SUN exerted synergistic effects on inhibiting the growth of SW1990 and PANC-1 pancreatic cancer cells. C2 significantly inhibited colony formation and migration of both cells. SW1990 xenograft and patient-derived xenograft (PDX) models were utilized for pharmacodynamic investigation in vivo. C2 alone showed little inhibition effect on tumor growth but increased the anti-tumor efficacy of SUN in both xenografts. Moreover, C2 down-regulated CSC markers (CD133 and ALDH) of both cancer cells and up-regulated the expression of dopamine receptor D1 (D1DR) in tumor. Besides, the SW1990 tumor growth was dose-dependently inhibited when the cells were pretreated with C2 before implantation. C2 increased intratumoral cAMP level, and the combination with D1DR specific antagonist SCH23390 reversed the above-mentioned effects of C2 both in vitro and in vivo, indicating the activation of D1DR may be involved in the underlying mechanism of C2 action. In summary, C2 could reduce the CSC frequency and enhance the anti-cancer effect of SUN in the treatment of pancreatic cancer, demonstrating its potential in cancer therapy.

The dichotomous function of interleukin-9 in cancer diseases

The pleiotropic function of the cytokine IL-9 is so far described in many inflammation processes and autoimmune diseases. But its role in cancer immunology is rather diverse as it can have a pro-tumorigenic function as well as anti-tumorigenic characteristics. In various disease models of cancer, this cytokine is involved in different signaling pathways triggering the expression of proteins involved in cell growth, migration, and transformation or repressing cells from the adaptive immune system to reject tumor growth. Additionally, there are even therapeutic approaches for IL-9 in cancer development. This review will give an overview of the various roles of IL-9 in different immune organs and cells and provide an insight in the current state of research in the IL-9-dependent cancer area.

The cell-penetrating FOXM1 N-terminus (M1-138) demonstrates potent inhibitory effects on cancer cells by targeting FOXM1 and FOXM1-interacting factor SMAD3

Transcription factor FOXM1 is involved in stimulating cell proliferation, enhancing DNA damage repair, promoting metastasis of cancer cells, and the inhibition of FOXM1 has been shown to prevent the initiation and progression of multiple cancers and FOXM1 is considered to be an effective target for tumor therapeutic drug development. The N-terminus of FOXM1 has been found to prevent transcriptional activities of FOXM1 and to mediate the interaction between FOXM1 and SMAD3.

Methods: A recombinant FOXM1 N-terminal domain (1-138aa) fused with a nine arginine cell-penetrating peptide is produced with an E. coli expression system and named as M1-138. The effects of M1-138 on the proliferation, migration, and tumorigenic ability of cancer cells are analyzed in vitro with cell counting, transwell assays, and colony formation assays. Electrophoretic mobility shift assays (EMSAs) and Luciferase activity assays are used to test the DNA binding ability and transcriptional activity of transcription factors. The levels of mRNAs and proteins are measured by quantitative-PCR, Western blotting or Immunohistochemistry. The interactions among proteins are analyzed with Pull-down and Co-immunoprecipitation (Co-IP) assays. The nude mouse engrafted tumor models are used to test the inhibitory effects of M1-138 in vivo.

Results: M1-138 diminishes the proliferation and migration abilities of cancer cells through binding to FOXM1 and FOXM1-interacting factor SMAD3, and consequently attenuating FOXM1 transcriptional activities from both direct and indirect FOXM1-promoter binding mechanisms and interfering with the interaction between FOXM1 and SMAD3. Treatment of M1-138 prevents tumorigenicity of cancer cells and inhibits tumor growth in nude mouse xenograft models with no obvious signs of toxicity.

Conclusion: M1-138 is a promising drug candidate for the development of anti-cancer therapeutics targeting FOXM1 and SMAD3.

Optimization of Peptidomimetics as Selective Inhibitors for the β-Catenin/T-Cell Factor Protein-Protein Interaction

The β-catenin/T-cell factor (Tcf) protein-protein interaction (PPI) plays a critical role in the β-catenin signaling pathway which is hyperactivated in many cancers and fibroses. Based on compound 1, which was designed to target the Tcf4 G¹³ANDE¹⁷ binding site of β-catenin, extensive structure-activity relationship studies have been conducted. As a result, compounds 53 and 57 were found to disrupt the β-catenin/Tcf PPI with the K_i values of 0.64 and 0.44 μM, respectively, and exhibit good selectivity for β-catenin/Tcf over β-catenin/E-cadherin and β-catenin/adenomatous polyposis coli (APC) PPIs. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium (MTS) cell viability assays revealed that 56, the ethyl ester of 53, was more potent than 53 in inhibiting viability of most of the Wnt/β-catenin hyperactive cancer cells. Further cell-based studies indicated that 56 disrupted the β-catenin/Tcf PPI without affecting the β-catenin/E-cadherin and β-catenin/APC PPIs, suppressed transactivation of Wnt/β-catenin signaling in dose-dependent manners, and inhibited migration and invasiveness of Wnt/β-catenin-dependent cancer cells.

Cancer stem cell associated eight gene-based signature predicts clinical outcomes of colorectal cancer

Previous studies have suggested that cancer stem cells serve crucial functions in tumorigenesis, metastasis and therapy failure. Stem cell signaling transduction pathways are frequently dysregulated in cancer and associated with tumorigenesis, metastasis and the cell cycle, which are necessary for cancer proliferation. However, cancer stem cell-associated gene signatures have not been established for predicting patient outcomes in colorectal cancer. Using a gene-mining approach, the present study performed mRNA expression profiling in large colorectal cancer cohorts from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database, including a TCGA colorectal cancer cohort (n=383) and three independent validation series GSE39582 (n=582), GSE17536 (n=177) and GSE17537 (n=55). The present study identified that an eight-gene signature in cancer stem cell signaling was associated with the overall survival and disease/recurrence-free survival of patients with colorectal. On the basis of this signature, patients in the TCGA training sets were divided into high-risk and low-risk subgroups with a significantly different overall survival rate (hazard ratio, 2.38; P=0.0005). The prognostic value of this signature was confirmed using three independent GEO colorectal cancer sets. Identifying this prognostic stem cell signaling signature may provide an efficient classification tool for clinical prognosis evaluation, and facilitate cancer stem cell-targeted therapy.

The anti-cancer activity of an andrographolide analogue functions through a GSK-3β-independent Wnt/β-catenin signaling pathway in colorectal cancer cells

The Wnt/β-catenin signaling pathway plays a key role in the progression of human colorectal cancers (CRCs) and is one of the leading targets of chemotherapy agents developed for CRC. The present study aimed to investigate the anti-cancer effects and molecular mechanisms of 19-O-triphenylmethyl andrographolide (RS-PP-050), an andrographolide analogue and determine its activity in the Wnt/β-catenin pathway. RS-PP-050 was found to potently inhibit the proliferation and survival of HT-29 CRC cells. It induces cell cycle arrest and promotes apoptotic cell death which was associated with the activation of PARP-1 and p53. Furthermore, RS-PP-050 exerts inhibitory effects on β-catenin transcription by suppressing T-cell factor/lymphocyte enhancer factor (TCF/LEF) activity in cells overexpressing β-catenin and by down-regulating the endogenous expression of Wnt target genes. RS-PP-050 also decreased the protein expression of the active form of β-catenin but functions independently of GSK-3β, a negative regulator of Wnt. Interestingly, RS-PP-050 extensively blocks phosphorylation at Ser675 of β-catenin which links to interference of the nuclear translocation of β-catenin and might contribute to Wnt inactivation. Collectively, our findings reveal the underlying anti-cancer mechanism of an andrographolide analogue and provide useful insight for exploiting a newly chemotherapeutic agent in Wnt/β-catenin-overexpressing CRC cells.

Tumor-targeting delivery of herb-based drugs with cell-penetrating/tumor-targeting peptide-modified nanocarriers

Cancer has become one of the leading causes of mortality globally. The major challenges of conventional cancer therapy are the failure of most chemotherapeutic agents to accumulate selectively in tumor cells and their severe systemic side effects. In the past three decades, a number of drug delivery approaches have been discovered to overwhelm the obstacles. Among these, nanocarriers have gained much attention for their excellent and efficient drug delivery systems to improve specific tissue/organ/cell targeting. In order to enhance targeting efficiency further and reduce limitations of nanocarriers, nanoparticle surfaces are functionalized with different ligands. Several kinds of ligand-modified nanomedicines have been reported. Cell-penetrating peptides (CPPs) are promising ligands, attracting the attention of researchers due to their efficiency to transport bioactive molecules intracellularly. However, their lack of specificity and in vivo degradation led to the development of newer types of CPP. Currently, activable CPP and tumor-targeting peptide (TTP)-modified nanocarriers have shown dramatically superior cellular specific uptake, cytotoxicity, and tumor growth inhibition. In this review, we discuss recent advances in tumor-targeting strategies using CPPs and their limitations in tumor delivery systems. Special emphasis is given to activable CPPs and TTPs. Finally, we address the application of CPPs and/or TTPs in the delivery of plant-derived chemotherapeutic agents.

Cell Penetrating Peptides as Molecular Carriers for Anti-Cancer Agents

Cell membranes with their selective permeability play important functions in the tight control of molecular exchanges between the cytosol and the extracellular environment as the intracellular membranes do within the internal compartments. For this reason the plasma membranes often represent a challenging obstacle to the intracellular delivery of many anti-cancer molecules. The active transport of drugs through such barrier often requires specific carriers able to cross the lipid bilayer. Cell penetrating peptides (CPPs) are generally 5-30 amino acids long which, for their ability to cross cell membranes, are widely used to deliver proteins, plasmid DNA, RNA, oligonucleotides, liposomes and anti-cancer drugs inside the cells. In this review, we describe the several types of CPPs, the chemical modifications to improve their cellular uptake, the different mechanisms to cross cell membranes and their biological properties upon conjugation with specific molecules. Special emphasis has been given to those with promising application in cancer therapy.

IGF-1-mediated PKM2/β-catenin/miR-152 regulatory circuit in breast cancer

Dysregulation of miRNAs is important in breast cancer initiation and malignant progression. Recently we showed that miR-152 downregulation is associated with breast cancer development, yet the underlying mechanism of miR-152 remains to be well elucidated. In this study, we identified β-catenin as a new direct target of miR-152. MiR-152 inhibited cell proliferation by targeting and inhibiting both β-catenin and PKM2 expression. We found that miR-152 expression sensitized the breast cancer cells to paclitaxel treatment by inhibiting β-catenin and PKM2 expression. Intriguingly, IGF-1 induced β-catenin and PKM2 expression and enhanced β-catenin and PKM2 interaction. Subsequently, IGF-1-induced β-catenin and PKM2 complex translocated into the nucleus, which in turn activated expression of miR-152. These results suggested a regulatory circuit between miR-152, β-catenin and PKM2 in breast cancer. By using human clinical specimens, we also showed that miR-152 expression levels were negatively correlated with β-catenin and PKM2 levels in breast cancer tissues. Our findings provide new insights into a mechanism of miR-152 involved in β-catenin and PKM2 inhibition which would have clinical implication for the cancer development and new treatment option in the future.

Targeted interference of SIN3A-TGIF1 function by SID decoy treatment inhibits Wnt signaling and invasion in triple negative breast cancer cells

Cancer cell invasion is an obligatory step for metastatic dissemination that contributes to rapid relapse and a poorer survival in triple negative breast cancer (TNBC) patients. Development of novel therapeutic strategies to block tumor invasion is an unmet need in the treatment of cancer. We reported that the selective inhibition of the PAH2 domain of SIN3A protein function markedly suppressed metastatic dissemination to the lungs in TNBC xenograft bearing mice. Here, we show that TNBC cell lines treated with Sin3 interaction domain (SID) decoy peptides that bind to PAH2 display a strong in vitro inhibition of transwell invasion. This is accompanied by actin cytoskeleton reorganization with increased cortical actin deposition and downregulation of known Wnt target genes that are associated with epithelial to mesenchymal transition (EMT) and cancer cell invasion. Wnt pathway inhibition by SID decoy peptide was confirmed by decreased Wnt reporter activity and altered cytoplasmic localization of nuclear β-catenin. TGIF1, a transcription factor that modulates Wnt signaling and known to interact with the PAH2 domain of SIN3A, can be dissociated from the SIN3A complex by SID decoys. TGIF1 knockdown inhibits WNT target genes and in vitro cell invasion suggesting that TGIF1 might be a key target of the SID decoys to block tumor invasion. Taken together, targeting SIN3 function using SID decoys is a novel strategy to reverse invasion and the EMT program in TNBC translating into the inhibition of metastasis dissemination and eradication of residual disease.

Dopamine D2 receptor antagonist sulpiride enhances dexamethasone responses in the treatment of drug-resistant and metastatic breast cancer

Recent evidence shows that dopamine D2-like receptor (D2DR) antagonists, such as trifluoperazine and thioridazine, are effective for cancer therapy and inhibition of cancer stem-like cells (CSCs). In this study, we investigated the anti-cancer effects of combination therapy of dexamethasone (DEX) and sulpiride (SUL), an atypical antipsychotic, against drug-resistant and metastatic breast cancers and further explored the underlying mechanisms. Oral administration of SUL (25, 100 mg·kg^-1·d^-1) alone did not inhibit the tumor growth in human breast cancer MCF-7/Adr xenograft model, but dose-dependently decreased the proportion of CSCs in vitro and in vivo. In contrast, combination therapy of SUL (50 mg·kg^-1·d^-1) and DEX (8 mg·kg^-1·d^-1) markedly suppressed the tumor growth in MCF-7/Adr xenograft model with little systemic toxicity and lung metastasis in murine metastatic breast cancer 4T1 xenograft model. Among the metastasis-associated biomarkers analyzed, the combination therapy significantly decreased the levels of MMP-2, but increased E-cadherin levels in 4T1 xenograft tumors. Moreover, the combination therapy significantly inhibited the cell colony formation, migration and invasion of 4T1 and human breast cancer MDA-MB-231 cells in vitro. Addition of a specific D2DR agonist 7-OH-DPAT to the combination therapy reversed the enhanced anti-cancer effects in vivo and CSC population loss in tumor tissues. Our data demonstrate that SUL remarkably enhances the efficacy of DEX in the treatment of drug-resistant and metastatic breast cancer via the antagonism of D2DR, which might result from the eradication of CSCs.

Regulation of CTNNB1 signaling in gastric cancer and stem cells

Recent research has shown that the alteration of combinations in gene expression contributes to cellular phenotypic changes. Previously, it has been demonstrated that the combination of cadherin 1 and cadherin 2 expression can identify the diffuse-type and intestinal-type gastric cancers. Although the diffuse-type gastric cancer has been resistant to treatment, the precise mechanism and phenotypic involvement has not been revealed. It may be possible that stem cells transform into gastric cancer cells, possibly through the involvement of a molecule alteration and signaling mechanism. In this review article, we focus on the role of catenin beta 1 (CTNNB1 or β-catenin) and describe the regulation of CTNNB1 signaling in gastric cancer and stem cells.