Acquisition of 5-fluorouracil resistance induces epithelial-mesenchymal transitions through the Hedgehog signaling pathway in HCT-8 colon cancer cells

Helminth-derived molecules improve 5-fluorouracil treatment on experimental colon tumorigenesis

Colorectal cancer (CRC) is one of the most prevalent fatal neoplasias worldwide. Despite efforts to improve the early diagnosis of CRC, the mortality rate of patients is still nearly 50%. The primary treatment strategy for CRC is surgery, which may be accompanied by chemotherapy and radiotherapy. The conventional and first-line chemotherapeutic agent utilized is 5-fluorouracil (5FU). However, it has low efficiency. Combination treatment with leucovorin and oxaliplatin or irinotecan improves the effectiveness of 5FU therapy. Unfortunately, most patients develop drug resistance, leading to disease progression. Here, we evaluated the effect of a potential alternative adjuvant treatment for 5FU, helminth-derived Taenia crassiceps (TcES) molecules, on treating advanced colitis-associated colon cancer. The use of TcES enhanced the effects of 5FU on established colonic tumors by downregulating the expression of the immunoregulatory cytokines, Il-10 and Tgf-β, and proinflammatory cytokines, Tnf-α and Il-17a, and reducing the levels of molecular markers associated with malignancy, cyclin D1, and Ki67, both involved in apoptosis inhibition and the signaling pathway of β-catenin. TcES+5FU therapy promoted NK cell recruitment and the release of Granzyme B1 at the tumor site, consequently inducing tumor cell death. Additionally, it restored P53 activity which relates to decreased Mdm2 expression. In vitro assays with human colon cancer cell lines showed that therapy with TcES+5FU significantly reduced cell proliferation and migration by modulating the P53 and P21 signaling pathways. Our findings demonstrate, for the first time in vivo, that helminth-derived excreted/secreted products may potentiate the effect of 5FU on established colon tumors.

5-Fluorouracil dose escalation generated desensitized colorectal cancer cells with reduced expression of protein methyltransferases and no epithelial-to-mesenchymal transition potential

Background

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers. In many cases, the poor prognosis of advanced CRC is associated with resistance to treatment with chemotherapeutic drugs such as 5-Fluorouracil (5-FU). The epithelial-to-mesenchymal transition (EMT) and dysregulation in protein methylation are two mechanisms associated with chemoresistance in many cancers. This study looked into the effect of 5-FU dose escalation on EMT and protein methylation in CRC.

Materials and Methods

HCT-116, Caco-2, and DLD-1 CRC cell lines were exposed to dose escalation treatment of 5-FU. The motility and invasive potentials of the cells before and after treatment with 5-FU were investigated through wound healing and invasion assays. This was followed by a Western blot which analyzed the protein expressions of the epithelial marker E-cadherin, mesenchymal marker vimentin, and the EMT transcription factor (EMT-TF), the snail family transcriptional repressor 1 (Snail) in the parental and desensitized cells. Western blotting was also conducted to study the protein expressions of the protein methyltransferases (PMTs), Euchromatic histone lysine methyltransferase 2 (EHMT2/G9A), protein arginine methyltransferase (PRMT5), and SET domain containing 7/9 (SETD7/9) along with the global lysine and arginine methylation profiles.

Results

The dose escalation method generated 5-FU desensitized CRC cells with distinct morphological features and increased tolerance to high doses of 5-FU. The 5-FU desensitized cells experienced a decrease in migration and invasion when compared to the parental cells. This was reflected in the observed reduction in E-cadherin, vimentin, and Snail in the desensitized cell lines. Additionally, the protein expressions of EHMT2/G9A, PRMT5, and SETD7/9 also decreased in the desensitized cells and global protein lysine and arginine methylation became dysregulated with 5-FU treatment.

Conclusion

This study showed that continuous, dose-escalation treatment of 5-FU in CRC cells generated 5-FU desensitized cancer cells that seemed to be less aggressive than parental cells.

Emerging trends in gastrointestinal cancers: Targeting developmental pathways in carcinogenesis and tumor progression

Gastrointestinal carcinomas are a group of cancers associated with the digestive system and its accessory organs. The most prevalent cancers related to the gastrointestinal tract are colorectal, gall bladder, gastric, hepatocellular, and esophageal cancers, respectively. Molecular aberrations in different signaling pathways, such as signal transduction systems or developmental pathways are the chief triggering mechanisms in different cancers Though a massive advancement in diagnostic and therapeutic interventions results in improved survival of patients with gastrointestinal cancer; the lower malignancy stages of these carcinomas are comparatively asymptomatic. Various gastrointestinal-related cancers are detected at advanced stages, leading to deplorable prognoses and increased rates of recurrence. Recent molecular studies have elucidated the imperative roles of several signaling pathways, namely Wnt, Hedgehog, and Notch signaling pathways, play in the progression, therapeutic responsiveness, and metastasis of gastrointestinal-related cancers. This book chapter gives an interesting update on recent findings on the involvement of developmental signaling pathways their mechanistic insight in gastrointestinalcancer. Subsequently, evidences supporting the exploration of gastrointestinal cancer related molecular mechanisms have also been discussed for developing novel therapeutic strategies against these debilitating carcinomas.

Evaluation of ARK5 and SIRT3 expression in renal cell carcinoma and their clinical significance

BACKGROUND

Globally Renal Cell Carcinoma (RCC) represents 3% of malignant tumours in adults and 1.78% in Egypt. AMPK-related protein kinase 5 (ARK5) is mainly associated with a hypoxic microenvironment which is a feature of the major RCC subtypes. Additionally, it displays decreased mitochondrial respiration. SIRT3 is a mitochondrial deacetylase that modifies multiple mitochondrial proteins.

MATERIAL AND METHODS

Fifty eight cases of RCC, and 30 non-neoplastic cases (of End-Stage Kidney Disease (ESKD) were subjected to immunohistochemistry by ARK5 and SIRT3. The results of IHC were correlated together and correlated with the available clinicopathologic and survival data.

RESULTS

Although no significant difference was detected between RCC and ESKD groups regarding ARK5 expression, there was a significant association with RCC regarding H-score and nucleocytoplasmic expression (both P = 0.001). Also, SIRT3 was highly expressed in RCC in comparison to the ESKD group (H-score: P = 0.001). There were significant associations between nucleocytoplasmic ARK5 expression and higher tumour grade, low apoptotic and high mitotic indices, tumour extent, advanced tumour stage, and impaired response of tumours to chemotherapeutic drugs (P = 0.039, P = 0.001, P = 0.027, P = 0.011, P = 0.009, and P = 0.014 respectively). Moreover, the H score of ARK5 expression showed significant associations with tumour grade, apoptotic and mitotic indices, tumour extension, tumour stage, and response to therapy (P = 0.01, 0.035, 0.001, 0.004. 0.003 and 0.013). Regarding SIRT3 expression, it showed significant associations with apoptotic and mitotic indices, tumour extent, tumour stage and response to therapy (P = 0.022, 0.02, 0.042, 0.039 and 0.027). Interestingly, there was a highly significant correlation between the expression of ARK5 and SIRT3 (P = 0.009). Univariate survival analysis revealed a significant association between short survival duration and both nucleocytoplasmic expression of ARK5 and positive SIRT3 expression (P = 0.014 and 0.035).

CONCLUSION

ARK5 and SIRT3 are overexpressed in RCC and associated with parameters of poor prognosis as well as short survival. Both seem to influence response to therapy in RCC. So, they could be new targets for therapy that may improve tumour response and patients' survival. There is a postulated relationship that needs more extensive investigation.

The Effects of Ovalbumin on Proliferation, Migration, and Stemness Properties of Chemoresistant SW480 Colon Cancer Cells

Egg peptides are factors in the embryonic environment with many significant biological activities, such as anticancer activity. Therefore, the current study investigates the effect of egg ovalbumin (OVA) on survival, cell cycle, self-renewal ability, stemness properties, and migration in SW480 colon cancer cells and 5-fluorouracil (5FU) resistant subgroup. MTT test was performed to assess cell viability. Flow cytometry was employed to analyze the cell cycle. Clonogenic assay and spheroid formation were used to assess the effect of OVA on self-renewal and stemness properties. Wound healing assay and RT-PCR were performed to analyze migration and gene mRNA expression. We demonstrated that OVA (8 and 12 mg/ml) attenuated cell viability, induced cell-cycle arrest, inhibited colony formation, and non-significantly reduced spheroid formation and migration in both cell lines. Furthermore, OVA downregulated the expression of Nanog, c-Myc, and NDRG1 in both cells, suggesting a stemness and self-renewal attenuation by OVA. In conclusion, OVA exposure inhibited the 5FU-SW480 chemo-resistant subpopulation growth by inducing cell cycle arrest and diminishing self-renewal and partially stemness properties of colon cancer cells.

Signaling Pathways Involved in 5-FU Drug Resistance in Cancer

Anti-metabolite drugs prevent the synthesis of essential cell growth compounds. 5-fluorouracil is used as an anti-metabolic drug in various cancers in the first stage of treatment. Unfortunately, in some cancers, 5-fluorouracil has low effectiveness because of its drug resistance. Studies have shown that drug resistance to 5-fluorouracil is due to the activation of specific signaling pathways and increased expressions of enzymes involved in drug metabolites. However, when 5-fluorouracil is used in combination with other drugs, the sensitivity of cancer cells to 5-fluorouracil increases, and the effect of drug resistance is reversed. This study discusses how the function of 5-fluorouracil in JAK/STAT, Wnt, Notch, NF-κB, and hedgehogs in some cancers.

Evening primrose seed extract rich in polyphenols modulates the invasiveness of colon cancer cells by regulating the TYMS expression

Natural polyphenols are plant metabolites exhibiting a broad range of biological activities.

Defining the Role of GLI/Hedgehog Signaling in Chemoresistance: Implications in Therapeutic Approaches

Insight into cancer signaling pathways is vital in the development of new cancer treatments to improve treatment efficacy. A relatively new but essential developmental signaling pathway, namely Hedgehog (Hh), has recently emerged as a major mediator of cancer progression and chemoresistance. The evolutionary conserved Hh signaling pathway requires an in-depth understanding of the paradigm of Hh signaling transduction, which is fundamental to provide the necessary means for the design of novel tools for treating cancer related to aberrant Hh signaling. This review will focus substantially on the canonical Hh signaling and the treatment strategies employed in different studies, with special emphasis on the molecular mechanisms and combination treatment in regard to Hh inhibitors and chemotherapeutics. We discuss our views based on Hh signaling's role in regulating DNA repair machinery, autophagy, tumor microenvironment, drug inactivation, transporters, epithelial-to-mesenchymal transition, and cancer stem cells to promote chemoresistance. The understanding of this Achilles' Heel in cancer may improve the therapeutic outcome for cancer therapy.

The Role of the Hedgehog Pathway in Chemoresistance of Gastrointestinal Cancers

The hedgehog pathway, which plays a significant role in embryonic development and stem cell regulation, is activated in gastrointestinal cancers. Chemotherapy is widely used in cancer treatment. However, chemoresistance becomes a substantial obstacle in cancer therapy. This review focuses on the recent advances in the hedgehog pathway's roles in drug resistance of gastrointestinal cancers and the novel drugs and strategies targeting hedgehog signaling.

Role of ARK5 in cancer and other diseases (Review)

Malignant tumors are often exposed to hypoxic and glucose-starved microenvironments. AMP-activated protein kinase (AMPK) is an energy sensor that is stimulated during energy-deficient conditions and protects cells from hypoxic injury by regulating metabolism. AMPK-related protein kinase 5 (ARK5) is a member of the catalytic sub-unit of the AMPK family and has an important role in energy regulation and hypoxia. ARK5 is regulated by Akt and liver kinase B1 and is associated with numerous tumor-related molecules to exert the negative effects of tumors. Studies have revealed ARK5 overexpression in cases of tumor invasion and metastasis and a positive association with the degree of cancer cell malignancy, which is regarded as a key element in determining cancer prognosis. Furthermore, ARK5 downregulation improves drug sensitivity through the epithelial-mesenchymal transition pathway, indicating that it may be a potential therapeutic target. In other non-cancer conditions, ARK5 has various roles in neurodegenerative diseases (Alzheimer's and Huntington's disease), renal disorders (diabetic nephropathy and renal fibrosis) and physiological processes (striated muscle generation). In the present review, the upstream and downstream molecular pathways of ARK5 in cancer and other diseases are described and potential therapeutic strategies are discussed.

The Combination of Zerumbone and 5-FU: A Significant Therapeutic Strategy in Sensitizing Colorectal Cancer Cells to Treatment

Objectives. Chemotherapy is considered to be essential in the treatment of patients with colorectal cancer (CRC), but drug resistance reduces its efficacy. Many patients with advanced CRC eventually show resistance to 5-fluorouracil (5-FU) therapy. Synergistic and potentiating effects of combination therapy, using herbal and chemical drugs, can improve patients’ response. Zerumbone (ZER), which is derived from ginger, has been studied for its growth inhibitory function in various types of cancer. Methods. The cytotoxic effects of ZER and 5-FU alone and their combination, on the SW48 and HCT-116 cells, were examined, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). The mRNA and protein levels of β-catenin, survivin, and vimentin were measured in treated CRC cells, using qRT-PCR and western blot. Colony formation assay, scratch test, and flow cytometry were performed to detect the changes of proliferation, migration, and apoptosis. Key Findings. In HCT-116- and SW48-treated cells, the proliferation, the gene and protein expression levels of the markers, the migration, the colony formation, and the survival rates were all significantly reduced compared to the control groups, and the sharpest decline was observed in the 5-FU+ZER treatment groups. Conclusions. Combination therapy has shown promising results in CRC cells, especially in drug-resistant cells.

Estrogen Receptor α Mediates Doxorubicin Sensitivity in Breast Cancer Cells by Regulating E-Cadherin

Anthracyclines resistance is commonly seen in patients with estrogen receptor α (ERα) positive breast cancer. Epithelial-mesenchymal transition (EMT), which is characterized with the loss of epithelial cell polarity, cell adhesion and acquisition of new invasive property, is considered as one of the mechanisms of chemotherapy-induced drug resistance. In order to identify factors that associated with doxorubicin resistance, we performed in vitro and in vivo experiments using human and mouse breast cancer cell lines with different ERα status. Cell survival experiments revealed that ERα-positive cells (MCF-7 and MCF-7/ADR cell lines), were less sensitive to doxorubicin than ERα-negative (MDA-MB-231, MDA-MB-468) cells, and mouse mammary carcinoma cells (4T-1). The expression of E-cadherin reduced in low-invasive ERα-positive MCF-7 cells after treatment with doxorubicin, indicating epithelial mesenchymal transition. In contrast, the expression of E-cadherin was upregulated in high-invasive ERα-negative cells, showing mesenchymal-epithelial transition (MET). Moreover, it was found that the growth inhibition of 4T-1 cells by doxorubicin was positively correlated with the expression of E-cadherin. In a mouse breast cancer xenograft model, E-cadherin was overexpressed in the primary tumor tissues of the doxorubicin-treated mice. In ERα-positive MCF-7 cells, doxorubicin treatment upregulated the expression of EMT-related transcription factors Snail and Twist, that regulate the expression of E-cadherin. Following overexpression of ERα in ERα-negative cells (MDA-MB-231 and MDA-MB-468), doxorubicin enhanced the upregulation of Snail and Twist, decreased expression of E-cadherin, and decreased the sensitivity of cells to doxorubicin. In contrast, inhibition of ERα activity increased the sensitivity to doxorubicin in ERα-positive MCF-7 cells. These data suggest that the regulation of Snail and/or Twist varies depends on different ERα status. Therefore, doxorubicin combined with anti-estrogen receptor α therapy could improve the treatment efficacy of doxorubicin in ERα-positive breast cancer.

Immunodetection of Epithelial-Mesenchymal Transition and Tumor Proliferation Markers in GLi-1-positive Oral Squamous Cell Carcinoma

In oral squamous cell carcinoma (OSCC), involvement and activation of the Hedgehog pathway (HH) may be related to epithelial-mesenchymal transition and cell proliferation. The present study aimed to evaluate epithelial-mesenchymal transition and proliferative potential in OSCC cases demonstrating activation of the HH pathway. Twenty-three GLi-1-positive OSCC cases were submitted to immunohistochemical detection of Snail, Slug, N-cadherin, E-cadherin, β-catenin, and MCM3 proteins. Clinical-pathologic immunoexpression data were obtained from the invasion front and tumor islets, and then compared. At the invasion front, OSCC cases presented positive Snail, Slug, and MCM3 expression in the nuclei of tumor cells. Loss of membrane and cytoplasmic expression of E-cadherin and β-catenin was also observed. Positive N-cadherin expression was observed in 31.78% of the cases. GLi-1 immunoexpression was associated with loss of membrane E-cadherin (P<0.001), membrane β-catenin (P<0.001), and cytoplasmic β-catenin (P=0.02) expression. In the tumor islets, we observed nuclear expression of GLi-1, Snail, Slug, and MCM3. E-cadherin and β-catenin showed positivity in tumor cell membranes. Statistically significant positive correlations between GLi-1 and Snail (P=0.05), E-cadherin (P=0.01), and cytoplasmic β-catenin (P=0.04) were found. GLi-1 was associated with clinical staging, while membrane β-catenin expression was related to the presence of metastasis in lymph nodes and to clinical staging. The HH pathway may be involved in regulating the expression of the mesenchymal phenotype. The loss of membrane E-cadherin and β-catenin expression was observed at the tumor front region, whereas cell adhesion protein expression was detected in tumor islets regardless of MCM3.

Cisplatin Protein Binding Partners and Their Relevance for Platinum Drug Sensitivity

Cisplatin is a widely used drug in the treatment of various solid tumors, such as ovarian cancer. However, while the acquired resistance significantly limits the success of therapy, some tumors, such as colorectal cancer, are intrinsically insensitive to cisplatin. Only a small amount of intracellular platinum binds to the target—genomic DNA. The fate of the remaining drug is largely obscure. This work aimed to identify the cytosolic protein binding partners of cisplatin in ovarian and colorectal cancer cells and to evaluate their relevance for cell sensitivity to cisplatin and oxaliplatin. Using the fluorescent cisplatin analog BODIPY-cisplatin, two-dimensional gel electrophoresis, and mass spectrometry, we identified the protein binding partners in A2780 and cisplatin-resistant A2780cis ovarian carcinoma, as well as in HCT-8 and oxaliplatin-resistant HCT-8ox colorectal cell lines. Vimentin, only identified in ovarian cancer cells; growth factor receptor-bound protein 2, only identified in colorectal cancer cells; and glutathione-S-transferase π, identified in all four cell lines, were further investigated. The effect of pharmacological inhibition and siRNA-mediated knockdown on cytotoxicity was studied to assess the relevance of these binding partners. The silencing of glutathione-S-transferase π significantly sensitized intrinsically resistant HCT-8 and HCT-8ox cells to cisplatin, suggesting a possible involvement of the protein in the resistance of colorectal cancer cells to the drug. The inhibition of vimentin with FiVe1 resulted in a significant sensitization of A2780 and A2780cis cells to cisplatin, revealing new possibilities for improving the chemosensitivity of ovarian cancer cells.

AMPK-related kinase 5 (ARK5) enhances gemcitabine resistance in pancreatic carcinoma by inducing epithelial-mesenchymal transition

AMPK-related kinase 5 (ARK5) is a member of the human AMP-activated protein kinase (AMPK) family, which is associated with increased tumor survival and drug resistance in many cancers. However, the function of ARK5 in pancreatic carcinoma (PC) is unclear. Our study investigated the role of ARK5 in the chemo-resistance of PC and its underlying mechanism. PC cell lines that displayed high expression levels of ARK5 had low sensitivity to gemcitabine (GEM). Suppression of ARK5 increased sensitivity to GEM in PC cell lines. Western blotting and immunofluorescence showed that suppression of ARK5 upregulated expression of E-cadherin and downregulated vimentin expression. Suppression of ARK5 also inhibited the epithelial-mesenchymal transition (EMT) efficiency associated with GEM in PC cell lines and upregulation of ARK5 expression enhanced GEM resistance in PC cell lines by inducing Twist-mediated EMT. In addition, we found that suppression of ARK5 increased GEM sensitivity in PC cell lines under hypoxic conditions. ARK5 increases GEM resistance in PC cell lines via EMT, and suppression of ARK5 increases sensitivity to GEM under both normoxic and hypoxic conditions.

Study of New Therapeutic Strategies to Combat Breast Cancer Using Drug Combinations

Cancer is a disease that affects and kills millions of people worldwide. Breast cancer, especially, has a high incidence and mortality, and is challenging to treat. Due to its high impact on the health sector, oncological therapy is the subject of an intense and very expensive research. To improve this therapy and reduce its costs, strategies such as drug repurposing and drug combinations have been extensively studied. Drug repurposing means giving new usefulness to drugs which are approved for the therapy of various diseases, but, in this case, are not approved for cancer therapy. On the other hand, the purpose of combining drugs is that the response that is obtained is more advantageous than the response obtained by the single drugs. Using drugs with potential to be repurposed, combined with 5-fluorouracil, the aim of this project was to investigate whether this combination led to therapeutic benefits, comparing with the isolated drugs. We started with a screening of the most promising drugs, with verapamil and itraconazole being chosen. Several cellular viability studies, cell death and proliferation studies, mainly in MCF-7 cells (Michigan Cancer Foundation-7, human breast adenocarcinoma cells) were performed. Studies were also carried out to understand the effect of the drugs at the level of possible therapeutic resistance, evaluating the epithelial-mesenchymal transition. Combining all the results, the conclusion is that the combination of verapamil and itraconazole with 5-fluorouracil had benefits, mainly by decreasing cell viability and proliferation. Furthermore, the combination of itraconazole and 5-fluorouracil seemed to be the most effective, being an interesting focus in future studies.

An extracellular matrix (ECM) model at high malignant colorectal tumor increases chondroitin sulfate chains to promote epithelial-mesenchymal transition and chemoresistance acquisition

Chemoresistance is one of the major barriers for tumor chemotherapy. It is clinically known that chemoresistance increases during tumor progression. Additionally, the extracellular matrix (ECM) is also remodeled during tumor progression. However, it remains unclear how ECM remodeling contributes to chemoresistance acquisition. Recently, it has been reported that epithelial-mesenchymal transition (EMT) contributes to chemoresistance acquisition. Here, how ECM remodeling contributes to 5-fluorouracil (5-FU) resistance acquisition was investigated from the viewpoints of EMT using in vitro ECM models mimicking native ECM in colorectal tumor tissue at three different malignant levels. 5-FU partially induced EMT and increased ABCB1 in colorectal HT-29 cells via TGF-β signaling (an invasive tumor cell model). When HT-29 cells were cultured on an ECM model (high malignant matrices) mimicking native ECM in highly malignant tumor tissues, the cells facilitated TGF-β-induced EMT and increased ABCB1 upregulation compared with that of other ECM models mimicking the low malignant level and normal tissues. High malignant matrices contained more chondroitin sulfate (CS) chains than those of other ECM models. Finally, CS chain-reduced high malignant matrices could not facilitate ABCB1 upregulation and TGF-β-induced EMT. These results demonstrated that ECM remodeling during tumor progression increased CS chains to facilitate EMT and ABCB1 upregulation, contributing to chemoresistance acquisition.

miR-206 regulates 5-FU resistance by targeting Bcl-2 in colon cancer cells

Introduction

Previous studies have found that miRNAs play a key role in drug resistance. Multiple reports show that miRNAs act as regulators in colorectal cancer (CRC) cells, but the role of miR-206 in CRC is still not well understood. The current study aimed to explore the potential function of miR-206 in 5-FU resistance.

Methods

To indentify the role of miR-206 in 5-FU resistance, the expression of miR-206 was examined by real-time polymerase chain reaction (RT-PCR) in 5-FU-resistant (FR) CRC (HCT116/FR and RKO/FR) and their parental cell lines. miR-206 mimic was transfected to 5-FU-FR CRC, and the 5-FU sensitivity was detected by MTS and flow cytometry. Using miRNA target prediction software, we found that miR-206 could target the 3′ untranslated region (3′UTR) sequence of Bcl-2.

Results

miR-206 was found to be downregulated in 5-FU-FR CRC in comparison with their parental cell lines, suggesting its crucial relevance for colon cancer biology. Downregulation of miR-206 promoted drug resistance and decreased apoptosis of parental cells, while overexpression of miR-206 promoted drug cytotoxicity and apoptosis of HCT116/FR cells. We also identified miR-206 targeting Bcl-2 directly in CRC, which is required for miR-206 mediated-5-FU resistance.

Conclusion

Our results show that miR-206 targets Bcl-2 to mediate chemoresistance, proliferation, and apoptosis in CRC. This study provides a novel promising candidate for colon cancer therapy.

The G protein-coupled P2Y₆ receptor promotes colorectal cancer tumorigenesis by inhibiting apoptosis

Colorectal tumors are immersed in an array of tumor-promoting factors including extracellular nucleotides such as uridine 5'‑diphosphate (UDP). UDP is the endogenous agonist of the G protein-coupled P2Y₆ receptor (P2Y₆R), which may contribute to the formation of a tumor-promoting microenvironment by coordinating resistance to apoptosis. Colorectal cancer (CRC) was chemically induced in P2ry6 knockout (P2ry6^-/-) mice using azoxymethane and dextran sulfate sodium challenges. Mice were euthanatized and their tumor load determined. Fixed tissues were stained for histological and immunohistochemistry analysis. Tumoroids were also prepared from CRC tumors resected from P2ry6^+/+ mice to determine the role of P2Y₆R in resistance to apoptosis, whereas HT29 carcinoma cells were used to elucidate the signaling mechanism involved in P2Y₆R anti-apoptotic effect. P2ry6^-/- mice developed a reduced number of colorectal tumors with apparent tumors having smaller volumes. Overall dysplastic score was significantly lower in P2ry6^-/- animals. Stimulation of P2Y₆R with the selective agonist MRS2693 protected HT-29 cells from TNFα-induced apoptosis. This protective effect was mediated by the stabilizing phosphorylation of the X-linked inhibitor of apoptosis protein (XIAP) by AKT. Using CRC-derived tumoroids, P2Y₆R activation was found to contribute to chemoresistance since addition of the P2Y₆R agonist MRS2693 significantly prevented the cytotoxic effect of 5-fluorouracil. The present study shows that sustained activation of P2Y₆R may contribute to intestinal tumorigenesis by blocking the apoptotic process and by contributing to chemoresistance, a substantial concern in the treatment of patients with CRC. These results suggest that P2Y₆R may represent a prime target for reducing colorectal carcinogenesis.

SMO Inhibition Modulates Cellular Plasticity and Invasiveness in Colorectal Cancer

HIGHLIGHTS Preliminary results of this work were presented at the 2016 Academic Surgical Congress, Jacksonville (FL), February 2-4 2016 (Original title: Selective Smo-Inhibition Interferes With Cellular Energetic Metabolism In Colorectal Cancer)This study was funded by "Sapienza-University of Rome" (Funds for young researchers) and "AIRC" (Italian Association for Cancer Research)Hedgehog inhibitor was kindly provided by Genentech, Inc.®. Colon Cancer (CC) is the fourth most frequently diagnosed tumor and the second leading cause of death in the USA. Abnormalities of Hedgehog pathway have been demonstrated in several types of human cancers, however the role of Hedgehog (Hh) in CC remain controversial. In this study, we analyzed the association between increased mRNA expression of GLI1 and GLI2, two Hh target genes, and CC survival and recurrence by gene expression microarray from a cohort of 382 CC patients. We found that patients with increased expression of GLI1 showed a statistically significant reduction in survival. In order to demonstrate a causal role of Hh pathway activation in the pathogenesis of CC, we treated HCT 116, SW480 and SW620 CC cells lines with GDC-0449, a pharmacological inhibitor of Smoothened (SMO). Treatment with GDC-0449 markedly reduced expression of Hh target genes GLI1, PTCH1, HIP1, MUC5AC, thus indicating that this pathway is constitutively active in CC cell lines. Moreover, GDC-0449 partially reduced cell proliferation, which was associated with upregulation of p21 and downregulation of CycD1. Finally, treatment with the same drug reduced migration and three-dimensional invasion, which were associated with downregulation of Snail1, the EMT master gene, and with induction of the epithelial markers Cytokeratin-18 and E-cadherin. These results were confirmed by SMO genetic silencing. Notably, treatment with 5E1, a Sonic Hedgehog-specific mAb, markedly reduced the expression of Hedgehog target genes, as well as inhibited cell proliferation and mediated reversion toward an epithelial phenotype. This suggests the existence of a Hedgehog autocrine signaling loop affecting cell plasticity and fostering cell proliferation and migration/invasion in CC cell lines. These discoveries encourage future investigations to better characterize the role of Hedgehog in cellular plasticity and invasion during the different steps of CC pathogenesis.

Distinct mechanisms contribute to acquired cisplatin resistance of urothelial carcinoma cells

Cisplatin (CisPt) is frequently used in the therapy of urothelial carcinoma (UC). Its therapeutic efficacy is limited by inherent or acquired drug resistance. Here, we comparatively investigated the CisPt-induced response of two different parental urothelial carcinoma cell lines (RT-112, J-82) with that of respective drug resistant variants (RT-112^R, J-82^R) obtained upon month-long CisPt selection. Parental RT-112 cells were ~2.5 fold more resistant to CisPt than J-82 cells and showed a different expression pattern of CisPt-related resistance factors. CisPt resistant RT-112^R and J-82^R variants revealed a 2–3-fold increased CisPt resistance as compared to their corresponding parental counterparts. Acquired CisPt resistance was accompanied by morphological alterations resembling epithelial mesenchymal transition (EMT). RT-112^R cells revealed lower apoptotic frequency and more pronounced G2/M arrest following CisPt exposure than RT-112 cells, whereas no differences in death induction were observed between J-82 and J-82^R cells. CisPt resistant J-82^R cells however were characterized by a reduced formation of CisPt-induced DNA damage and related DNA damage response (DDR) as compared to J-82 cells. Such difference was not observed between RT-112^R and RT-112 cells. J-82^R cells showed an enhanced sensitivity to pharmacological inhibition of checkpoint kinase 1 (Chk1) and, moreover, could be re-sensitized to CisPt upon Chk1 inhibition. Based on the data we suggest that mechanisms of acquired CisPt resistance of individual UC cells are substantially different, with apoptosis- and DDR-related mechanisms being of particular relevance. Moreover, the findings indicate that targeting of Chk1 might be useful to overcome acquired CisPt resistance of certain subtypes of UC.

ARK5 promotes invasion and migration in hepatocellular carcinoma cells by regulating epithelial-mesenchymal transition

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated mortality worldwide. The highly invasive nature of HCC leads to poor prognosis in patients with malignant HCC. AMPK-related protein kinase 5 (ARK5) is a key mediator of migratory activity in human cancer cells. However, the role of ARK5 in invasion and metastasis of HCC cells remains unclear. The present study attempted to determine whether ARK5 is involved in invasion and migration via regulation of epithelial-mesenchymal transition (EMT). Wound healing and Transwell Matrigel invasion assays were utilized to detect the ability of the epithelial Huh7 and mesenchymal SNU387 HCC cells to migrate and invade. Next, the expression of ARK5 and EMT markers, E-cadherin and vimentin, were examined by western blot analysis. Inhibition of ARK5 was able to significantly reduce the ability HCC cells to invade and metastasize. Furthermore, the knockdown of ARK5 was able to reverse the process of EMT in HCC cells. These data suggested that ARK5 may serve an important role in regulating EMT in HCC cells. Taken together, these findings indicate that ARK5 is a potential molecular target for the development of novel HCC therapeutics, which focus on cell invasion and EMT regulation.

MiR-26b reverses temozolomide resistance via targeting Wee1 in glioma cells

Emerging evidence has demonstrated that microRNAs (miRNA) play a critical role in chemotherapy-induced epithelial-mesenchymal transition (EMT) in glioma. However, the underlying mechanism of chemotherapy-triggered EMT has not been fully understood. In the current study, we determined the role of miR-26b in regulation of EMT in stable temozolomide (TMZ)-resistant (TR) glioma cells, which have displayed mesenchymal features. Our results illustrated that miR-26b was significantly downregulated in TR cells. Moreover, ectopic expression of miR-26b by its mimics reversed the phenotype of EMT in TR cells. Furthermore, we found that miR-26b governed TR-mediate EMT partly due to governing its target Wee1. Notably, overexpression of miR-26b sensitized TR cells to TMZ. These findings suggest that upregulation of miR-26b or targeting Wee1 could serve as novel approaches to reverse chemotherapy resistance in glioma.

Preoperative chemoradiotherapy for rectal cancer: the sensitizer role of the association between miR-375 and c-Myc

Administration of chemoradiation before tumor resection has revolutionized the management of locally advanced rectal cancer, but many patients have proven resistant to this preoperative therapy. Our group recently reported a negative correlation between c-Myc gene expression and this resistance. In the present study, integrated analysis of miRNA and mRNA expression profiles was conducted in 45 pre-treatment rectal tumors in order to analyze the expressions of miRNAs and c-Myc and their relationship with clinicopathological factors and patient survival. Twelve miRNAs were found to be differentially expressed by responders and non-responders to the chemoradiation. Functional classification revealed an association between the differentially expressed miRNAs and c-Myc. Quantitative real-time PCR results showed that miRNA-148 and miRNA-375 levels were both significantly lower in responders than in non-responders. Notably, a significant negative correlation was found between miRNA-375 expression and c-Myc expression. According to these findings, miRNA-375 and its targeted c-Myc may be useful as a predictive biomarker of the response to neoadjuvant treatment in patients with locally advanced rectal cancer.

Hedgehog signaling pathway in colorectal cancer: function, mechanism, and therapy

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. It is a complicated and often fatal cancer, and is related to a high disease-related mortality. Around 90% of mortalities are caused by the metastasis of CRC. Current treatment statistics shows a less than 5% 5-year survival for patients with metastatic disease. The development and metastasis of CRC involve multiple factors and mechanisms. The Hedgehog (Hh) signaling plays an important role in embryogenesis and somatic development. Abnormal activation of the Hh pathway has been proven to be related to several types of human cancers. The role of Hh signaling in CRC, however, remains controversial. In this review, we will go through previous literature on the Hh signaling and its functions in the formation, proliferation, and metastasis of CRC. We will also discuss the potential of targeting Hh signaling pathway in the treatment, prognosis, and prevention of CRC.

Human Mesenchymal Stem Cells Partially Reverse Infertility in Chemotherapy-Induced Ovarian Failure

INTRODUCTION

Chemotherapy is the most commonly used modality to treat human cancers; however, in many cases it causes irreversible ovarian failure. In this work, we plan to evaluate the restorative function of human bone marrow mesenchymal stem cells (BMSCs) in a chemotherapy-induced ovarian failure mouse model.

METHODS

Acclimatized 4 to 6 week-old female mice (C57BL/6) were assigned randomly to a vehicle-treated control group (group 1), chemotherapy-treated group followed by vehicle alone (group 2), or chemotherapy-treated group followed by stem cell intraovarian injection (group 3). Outcomes were evaluated using immunohistochemistry (IHC), serum hormonal assays, and estrous cycle monitoring and breeding potential.

RESULTS

Post BMSCs administration, group 3 promptly showed detectable vaginal smears with estrogenic changes. Increase in total body weight, ovarian weight, and weight of estrogen-responsive organs (uterus and liver) was observed at 2 weeks and continued to end of the experiment. Hematoxylin and Eosin histological evaluation of the ovaries demonstrated a higher mean follicle count in group 3 than in group 2. Group 3 had lower follicle-stimulating hormone (FSH) levels ( P = .03) and higher anti-Müllerian hormone serum (AMH) levels ( P = .0005) than group 2. The IHC analysis demonstrated higher expression of AMH, FSH receptor, inhibin A, and inhibin B in growing follicles of group 3 versus group 2. Tracking studies demonstrated that human BMSCs evenly repopulated the growing follicles in treated ovaries. Importantly, breeding data showed significant increases in the pregnancies numbers, 2 pregnancies in group 1 and 12 in group 3 ( P = .02).

CONCLUSIONS

Intraovarian administered BMSCs are able to restore ovarian hormone production and reactivate folliculogenesis in chemotherapy-induced ovarian failure mouse model.

MicroRNA-330 inhibited cell proliferation and enhanced chemosensitivity to 5-fluorouracil in colorectal cancer by directly targeting thymidylate synthase

Colorectal cancer (CRC) is the third most common cancer in males and the second most common in females, worldwide. Currently, 5-fluorouracil (5-FU)-mediated chemotherapy is the adjuvant treatment for patients with CRC following surgical resection. However, a number of patients with CRC develop 5-FU resistance, which is a major challenge for the effective treatment of cancer. Therefore, it is important to investigate the molecular mechanisms underlying chemoresistance and the therapeutic treatments that may improve the treatment of CRC. The present study demonstrated that microRNA (miR)-330 was significantly downregulated in CRC tissues and cell lines. Ectopic miR-330 expression decreased cell proliferation and enhanced cell chemosensitivity to 5-FU via the cell apoptosis pathway in CRC. In addition, thymidylate synthase (TYMS) was revealed to be a direct target gene of miR-330 in CRC. Knockdown of TYMS inhibited CRC cell proliferation, and enhanced cell chemosensitivity to 5-FU by promoting cell apoptosis. In conclusion, the results of the present study indicated that miR-330 targeted TYMS to inhibit the proliferation and enhance the chemosensitivity of CRC cells to 5-FU by promoting cell apoptosis. The present study provided important insight into the molecular mechanism underlying 5-FU-mediated chemoresistance and a novel therapeutic strategy for the enhancement of efficacy in CRC treatment.

TET1 promotes cisplatin-resistance via demethylating the vimentin promoter in ovarian cancer

The development of chemo-resistance impairs the outcome of the first line platinum-based chemotherapies for ovarian cancer. Deregulation of DNA methylation/demethylation provides a critical mechanism for the occurrence of chemo-resistance. The ten-eleven translocation (TET) family of dioxygenases including TET1/2/3 plays an important part in DNA demethylation, but their roles in cisplatin resistance have not been elucidated. Using cisplatin-sensitive and cisplatin-resistant ovarian cancer cell models, we found that TET1 was significantly upregulated in cisplatin-resistant CP70 cells compared with that in cisplatin-sensitive A2780 cells. Ectopic expression of TET1 in A2780 cells promoted cisplatin resistance and decreased cytotoxicity induced by cisplatin, while inhibition of TET1 by siRNA transfection in CP70 cells attenuated cisplatin resistance and enhanced cytotoxicity of cisplatin. Increased TET1 induced re-expression of vimentin through active DNA demethylation, and cause partial epithelial-to-mesenchymal (EMT) in A2780 cells. Contrarily, knocking down of TET1 in CP70 cells reduced vimentin expression and reversed EMT process. Immunohistochemical analysis of TET1 in human ovarian cancer tissues revealed that TET1 existed in nucleus and cytoplasm in ovarian cancer tissues. And the expression of nuclear TET1 was positively correlated with residual tumor and chemotherapeutic response. Thus, TET1 expression causes resistance to cisplatin and one of the targets of TET1 action is vimentin in ovarian cancer.

MicroRNA-9 regulates non-small cell lung cancer cell invasion and migration by targeting eukaryotic translation initiation factor 5A2

MicroRNAs (miRNAs) play a critical role in cancer development and progression. Bioinformatics analyses has identified eukaryotic translation initiation factor 5A2 (eIF5A2) as a target of miR-9. In this study, we attempted to determine whether miR-9 regulates non-small cell lung cancer (NSCLC) cell invasion and migration by targeting eIF5A2 We examined eIF5A2 expression using reverse transcription-quantitative PCR (RT-qPCR) and subsequently transfected A549 and NCI-H1299 NSCLC cells with a miR-9 mimic or miR-9 inhibitor to determine the migration and invasive capability of the cells via wound healing assay and Transwell invasion assay, respectively. E-cadherin and vimentin expression was detected with western blotting. The miR-9 mimic significantly reduced NSCLC cell invasive and metastatic ability, and the miR-9 inhibitor enhanced NSCLC cell migration activity, increasing the number of migrated cells. There was no significant difference between the negative control siRNA and miR-9 mimic groups after knockdown of eIF5A2; western blotting showed that miR-9 regulated E-cadherin and vimentin expression. These data show that miR-9 regulates NSCLC cell invasion and migration through regulating eIF5A2 expression. Taken together, our findings suggest that the mechanism of miR-9-regulated NSCLC cell invasion and migration may be related to epithelial-mesenchymal transition.

SHh-Gli1 signaling pathway promotes cell survival by mediating baculoviral IAP repeat-containing 3 (BIRC3) gene in pancreatic cancer cells

The abnormally activated hedgehog (Hh) signaling pathway is involved in the regulation of proliferation and apoptosis in pancreatic cancer cells, while its exact molecular mechanism is not clear. The purpose of this study was to investigate the regulatory effect of Hh signaling pathway on the transcription of BIRC3 gene and its underlying mechanism in pancreatic cancer cells, as well as the relationship between the Gli1-dependent BIRC3 transcription and cell survival. Firstly, we examined the effect of knockdown or overexpression of Hh on BIRC3 messenger RNA (mRNA) expression by real-time RT-PCR. Then, the regulatory mechanism of Gli1 to BIRC3 gene transcription was investigated by XChIP-PCR and luciferase assays. Finally, the cell survival mediated by the Gli1-dependent BIRC3 transcription was studied by MTT and annexin V-FITC/propidiumiodide (PI) assays. We found that the expression level of BIRC3 mRNA was positively correlated to SHh/Gli1 signaling activation in three pancreatic cancer cell lines. The XChIP-PCR and luciferase assays data showed that the transcription factor Gli1 bound to some enhancers within the promoter regions of BIRC3 gene and promoted gene transcription. The cell proliferation was increased significantly by SHh/Gli1 expression while the apoptotic rate was reduced under the same condition. Moreover, BIRC3 knockdown inhibited cell proliferation and survival induced by SHh overexpression. Our study reveals that Gli1 promoted transcription of BIRC3 gene via cis-acting elements and the SHh-Gli1 signaling pathway maintained cell survival partially through this Gli1-dependent BIRC3 model in pancreatic cancer cells.

Endothelial Transdifferentiation of Tumor Cells Triggered by the Twist1-Jagged1-KLF4 Axis: Relationship between Cancer Stemness and Angiogenesis

Tumor hypoxia is associated with malignant biological phenotype including enhanced angiogenesis and metastasis. Hypoxia increases the expression of vascular endothelial cell growth factor (VEGF), which directly participates in angiogenesis by recruiting endothelial cells into hypoxic area and stimulating their proliferation, for increasing vascular density. Recent research in tumor biology has focused on the model in which tumor-derived endothelial cells arise from tumor stem-like cells, but the detailed mechanism is not clear. Twist1, an important regulator of epithelial-mesenchymal transition (EMT), has been shown to mediate tumor metastasis and induce tumor angiogenesis. Notch signaling has been demonstrated to be an important player in vascular development and tumor angiogenesis. KLF4 (Krüppel-like factor 4) is a factor commonly used for the generation of induced pluripotent stem (iPS) cells. KLF4 also plays an important role in the differentiation of endothelial cells. Although Twist1 is known as a master regulator of mesoderm development, it is unknown whether Twist1 could be involved in endothelial transdifferentiation of tumor-derived cells. This review focuses on the role of Twist1-Jagged1/Notch-KLF4 axis on tumor-derived endothelial transdifferentiation, tumorigenesis, metastasis, and cancer stemness.