LGR5 promotes cancer stem cell traits and chemoresistance in cervical cancer

Wnt signaling and tumors (Review)

Wnt signaling is a highly conserved evolutionary pathway that plays a key role in regulation of embryonic development, as well as tissue homeostasis and regeneration. Abnormalities in Wnt signaling are associated with tumorigenesis and development, leading to poor prognosis in patients with cancer. However, the pharmacological effects and mechanisms underlying Wnt signaling and its inhibition in cancer treatment remain unclear. In addition, potential side effects of inhibiting this process are not well understood. Therefore, the present review outlines the role of Wnt signaling in tumorigenesis, development, metastasis, cancer stem cells, radiotherapy resistance and tumor immunity. The present review further identifies inhibitors that target Wnt signaling to provide a potential novel direction for cancer treatment. This may facilitate early application of safe and effective drugs targeting Wnt signaling in clinical settings. An in-depth understanding of the mechanisms underlying inhibition of Wnt signaling may improve the prognosis of patients with cancer.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

Targeted immunotherapy to cancer stem cells: A novel strategy of anticancer immunotherapy

Cancer is a major disease that endangers human health. Cancer drug resistance and relapse are the two main causes contributing to cancer treatment failure. Cancer stem cells (CSCs) are a small fraction of tumor cells that are responsible for tumorigenesis, metastasis, relapse, and resistance to conventional anticancer therapies. Therefore, CSCs are considered to be the root of cancer recurrence, metastasis, and drug resistance. Novel anticancer strategies need to face this new challenge and explore their efficacy against CSCs. Recently, immunotherapy has made rapid advances in cancer treatment, and its potential against CSCs is also an interesting area of research. Meanwhile, immunotherapy strategies are novel therapeutic modalities with promising results in targeting CSCs. In this review, we summarize the targeting of CSCs by various immunotherapy strategies such as monoclonal antibodies(mAb), tumor vaccines, immune checkpoint inhibitors, and chimeric antigen receptor-T cells(CAR-T) in pre-clinical and clinical studies. This review provides new insights into the application of these immunotherapeutic approaches to potential anti-tumor therapies in the future.

Death-associated protein 3 in cancer-discrepant roles of DAP3 in tumours and molecular mechanisms

Cancer, ranks as the secondary cause of death, is a group of diseases that are characterized by uncontrolled tumor growth and distant metastasis, leading to increased mortality year-on-year. To date, targeted therapy to intercept the aberrant proliferation and invasion is crucial for clinical anticancer treatment, however, mutant expression of target genes often leads to drug resistance. Therefore, it is essential to identify more molecules that can be targeted to facilitate combined therapy. Previous studies showed that death associated protein 3 (DAP3) exerts a pivotal role in regulating apoptosis signaling of tumors, meanwhile, aberrant DAP3 expression is associated with the tumorigenesis and disease progression of various cancers. This review provides an overview of the molecule structure of DAP3 and the discrepant roles played by DAP3 in various types of tumors. Considering the molecular mechanism of DAP3-regulated cancer development, new potential treatment strategies might be developed in the future.

Unveiling diagnostic and therapeutic strategies for cervical cancer: biomarker discovery through proteomics approaches and exploring the role of cervical cancer stem cells

Cervical cancer (CC) is a major global health problem and leading cause of cancer deaths among women worldwide. Early detection through screening programs has reduced mortality; however, screening compliance remains low. Identifying non-invasive biomarkers through proteomics for diagnosis and monitoring response to treatment could improve patient outcomes. Here we review recent proteomics studies which have uncovered biomarkers and potential drug targets for CC. Additionally, we explore into the role of cervical cancer stem cells and their potential implications in driving CC progression and therapy resistance. Although challenges remain, proteomics has the potential to revolutionize the field of cervical cancer research and improve patient outcomes.

Cancer stem cells: a target for overcoming therapeutic resistance and relapse

Cancer stem cells (CSCs) are a small subset of cells in cancers that are thought to initiate tumorous transformation and promote metastasis, recurrence, and resistance to treatment. Growing evidence has revealed the existence of CSCs in various types of cancers and suggested that CSCs differentiate into diverse lineage cells that contribute to tumor progression. We may be able to overcome the limitations of cancer treatment with a comprehensive understanding of the biological features and mechanisms underlying therapeutic resistance in CSCs. This review provides an overview of the properties, biomarkers, and mechanisms of resistance shown by CSCs. Recent findings on metabolic features, especially fatty acid metabolism and ferroptosis in CSCs, are highlighted, along with promising targeting strategies. Targeting CSCs is a potential treatment plan to conquer cancer and prevent resistance and relapse in cancer treatment.

Epigenetic control of cell signalling in cancer stem cells

The self-renewing cancer stem cells (CSCs) represent one of the distinct cell populations occurring in a tumour that can differentiate into multiple lineages. This group of sparsely abundant cells play a vital role in tumour survival and resistance to different treatments during cancer. The lack of exclusive markers associated with CSCs makes diagnosis and prognosis in cancer patients extremely difficult. This calls for the identification of unique regulators and markers for CSCs. Various signalling pathways like the Wnt/β-catenin pathway, Hedgehog pathway, Notch pathway, and TGFβ/BMP play a major role in the regulation and maintenance of CSCs. Epigenetic regulatory mechanisms add another layer of complexity to control these signalling pathways. In this chapter, we discuss about the role of epigenetic mechanisms in regulating the cellular signalling pathways in CSCs. The epigenetic regulatory mechanisms such as DNA methylation, histone modification and microRNAs can modulate the diverse effectors of signalling pathways and consequently the growth, differentiation and tumorigenicity of CSCs. In the end, we briefly discuss the therapeutic potential of targeting these epigenetic regulators and their target genes in CSCs.

Insights on the Role of Polyphenols in Combating Cancer Drug Resistance

Chemotherapy resistance is still a serious problem in the treatment of most cancers. Many cellular and molecular mechanisms contribute to both inherent and acquired drug resistance. They include the use of unaffected growth-signaling pathways, changes in the tumor microenvironment, and the active transport of medicines out of the cell. The antioxidant capacity of polyphenols and their potential to inhibit the activation of procarcinogens, cancer cell proliferation, metastasis, and angiogenesis, as well as to promote the inhibition or downregulation of active drug efflux transporters, have been linked to a reduced risk of cancer in epidemiological studies. Polyphenols also have the ability to alter immunological responses and inflammatory cascades, as well as trigger apoptosis in cancer cells. The discovery of the relationship between abnormal growth signaling and metabolic dysfunction in cancer cells highlights the importance of further investigating the effects of dietary polyphenols, including their ability to boost the efficacy of chemotherapy and avoid multidrug resistance (MDR). Here, it is summarized what is known regarding the effectiveness of natural polyphenolic compounds in counteracting the resistance that might develop to cancer drugs as a result of a variety of different mechanisms.

Spatial Transcriptomics Depict Ligand-Receptor Cross-talk Heterogeneity at the Tumor-Stroma Interface in Long-Term Ovarian Cancer Survivors

Advanced high-grade serous ovarian cancer (HGSC) is an aggressive disease that accounts for 70% of all ovarian cancer deaths. Nevertheless, 15% of patients diagnosed with advanced HGSC survive more than 10 years. The elucidation of predictive markers of these long-term survivors (LTS) could help identify therapeutic targets for the disease, and thus improve patient survival rates. To investigate the stromal heterogeneity of the tumor microenvironment (TME) in ovarian cancer, we used spatial transcriptomics to generate spatially resolved transcript profiles in treatment-naïve advanced HGSC from LTS and short-term survivors (STS) and determined the association between cancer-associated fibroblasts (CAF) heterogeneity and survival in patients with advanced HGSC. Spatial transcriptomics and single-cell RNA-sequencing data were integrated to distinguish tumor and stroma regions, and a computational method was developed to investigate spatially resolved ligand-receptor interactions between various tumor and CAF subtypes in the TME. A specific subtype of CAFs and its spatial location relative to a particular ovarian cancer cell subtype in the TME correlated with long-term survival in patients with advanced HGSC. Also, increased APOE-LRP5 cross-talk occurred at the stroma-tumor interface in tumor tissues from STS compared with LTS. These findings were validated using multiplex IHC. Overall, this spatial transcriptomics analysis revealed spatially resolved CAF-tumor cross-talk signaling networks in the ovarian TME that are associated with long-term survival of patients with HGSC. Further studies to confirm whether such cross-talk plays a role in modulating the malignant phenotype of HGSC and could serve as a predictive biomarker of patient survival are warranted.

SIGNIFICANCE

Generation of spatially resolved gene expression patterns in tumors from patients with ovarian cancer surviving more than 10 years allows the identification of novel predictive biomarkers and therapeutic targets for better patient management. See related commentary by Kelliher and Lengyel, p. 1383.

Elevated Expression of LGR5 and WNT Signaling Factors in Neuroblastoma Cells With Acquired Drug Resistance

Neuroblastoma (NB) is a pediatric solid cancer with high fatality, relapses, and acquired resistance to chemotherapy, that requires new therapeutic approaches to improve survival. LGR5 is a receptor that potentiates WNT/signaling pathway and has been reported to promote development and survival in several adult cancers. In this study we investigated LGR5 expression in a panel of NB cell lines with acquired resistance to vincristine or doxorubicin. We show LGR5-LRP6 cooperation with enhanced expression in drug resistant NB cell lines compared to parental cells, suggesting a role for LGR5 in the emergence of drug resistance, warranting further investigation.

Cervical cancer heterogeneity: a constant battle against viruses and drugs

Cervical cancer is the first identified human papillomavirus (HPV) associated cancer and the most promising malignancy to be eliminated. However, the ever-changing virus subtypes and acquired multiple drug resistance continue to induce failure of tumor prevention and treatment. The exploration of cervical cancer heterogeneity is the crucial way to achieve effective prevention and precise treatment. Tumor heterogeneity exists in various aspects including the immune clearance of viruses, tumorigenesis, neoplasm recurrence, metastasis and drug resistance. Tumor development and drug resistance are often driven by potential gene amplification and deletion, not only somatic genomic alterations, but also copy number amplifications, histone modification and DNA methylation. Genomic rearrangements may occur by selection effects from chemotherapy or radiotherapy which exhibits genetic intra-tumor heterogeneity in advanced cervical cancers. The combined application of cervical cancer therapeutic vaccine and immune checkpoint inhibitors has become an effective strategy to address the heterogeneity of treatment. In this review, we will integrate classic and recently updated epidemiological data on vaccination rates, screening rates, incidence and mortality of cervical cancer patients worldwide aiming to understand the current situation of disease prevention and control and identify the direction of urgent efforts. Additionally, we will focus on the tumor environment to summarize the conditions of immune clearance and gene integration after different HPV infections and to explore the genomic factors of tumor heterogeneity. Finally, we will make a thorough inquiry into completed and ongoing phase III clinical trials in cervical cancer and summarize molecular mechanisms of drug resistance among chemotherapy, radiotherapy, biotherapy, and immunotherapy.

LGR5 promotes invasion and migration by regulating YAP activity in hypopharyngeal squamous cell carcinoma cells under inflammatory condition

High leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5) expression caused by an inflammatory condition was reported to promote tumor proliferation and the epithelial-mesenchymal transition (EMT) in various malignant tumors, but those effects have not been studied in hypopharyngeal squamous cell carcinoma (HSCC) and the molecular mechanism remains unclear. This study was aimed to determine whether YAP/TAZ is involved in the regulation of LGR5 expression in the inflammatory condition. Human hypopharyngeal carcinoma FaDu cells were stimulated with inflammatory medium. The cell invasion ability were evaluated through wound healing assay and transwell invasion assay. The expression levels of EMT-related proteins, LGR5, and p-YAP were detected by real time PCR, western blotting, and immunofluorescence. The results showed that LGR5 expression and the EMT process were significantly enhanced under inflammatory condition. The expression of EMT-related proteins was up-regulated, while that of p-YAP was decreased. After inhibiting the high LGR5 expression with short interfering RNA, the expression of EMT-related proteins was also down-regulated, while that of p-YAP was significantly increased. The use of verteporfin (VP), an inhibitor of YAP activity that promotes YAP phosphorylation, did not affect LGR5 expression. In conclusion, we suggest that the inflammatory condition leads to high LGR5 expression, which up-regulating the expression of EMT-related proteins by inhibiting the YAP phosphorylation.

MmuPV1-Induced Cutaneous Squamous Cell Carcinoma Arises Preferentially from Lgr5+ Epithelial Progenitor Cells

Murine papillomavirus, MmuPV1, causes natural infections in laboratory mice that can progress to squamous cell carcinoma (SCC) making it a useful preclinical model to study the role of papillomaviruses in cancer. Papillomavirus can infect cells within hair follicles, which contain multiple epithelial progenitor cell populations, including Lgr5+ progenitors, and transgenic mice expressing human papillomavirus oncogenes develop tumors derived from Lgr5 progenitors. We therefore tested the hypothesis that Lgr5+ progenitors contribute to neoplastic lesions arising in skins infected with MmuPV1 by performing lineage tracing experiments. Ears of 6-8-week-old Lgr5-eGFP-IRES-CreERT2/Rosa26LSLtdTomato mice were treated topically with 4-OH Tamoxifen to label Lgr5+ progenitor cells and their progeny with tdTomato and, 72 h later, infected with MmuPV1. Four months post-infection, tissue at the infection site was harvested for histopathological analysis and immunofluorescence to determine the percentage of tdTomato+ cells within the epithelial lesions caused by MmuPV1. Squamous cell dysplasia showed a low percentage of tdTomato+ cells (7%), indicating that it arises primarily from non-Lgr5 progenitor cells. In contrast, cutaneous SCC (cSCC) was substantially more positive for tdTomato+ cells (42%), indicating that cSCCs preferentially arise from Lgr5+ progenitors. Biomarker analyses of dysplasia vs. cSCC revealed further differences consistent with cSCC arising from LGR5+ progenitor cells.

Cytotoxic effect of disulfiram/copper on human cervical cancer cell lines and LGR5-positive cancer stem-like cells

BACKGROUND

Tumor resistance is a global challenge for tumor treatment. Cancer stem cells (CSCs) are the main population of tumor cells for drug resistance. We have reported that high aldehyde dehydrogenase (ALDH) activity represents a functional marker for cervical CSCs. Here, we aimed at disulfiram (DSF), an ALDH inhibitor, that has the potential to be used for cervical cancer treatment.

METHODS

MTT assay, western blot, vector construction and transfection, cell sorting and in vivo anti-tumor assays were performed using cervical cancer cell lines SiHa and HeLa. Cell cycle distribution and cell apoptosis were carried out by flow cytometry. The cytotoxicity of DSF was detected by MTT assay and cervical cancer xenograft models.

RESULTS

DSF was cytotoxic to cervical cancer cell lines in a copper (Cu)-dependent manner. Disulfiram/copper (DSF/Cu) complex induced deregulation of S-phase and inhibited the expression of stemness markers in cervical cancer cells. Furthermore, DSF/Cu could also reduce the cancer stem cell-like LGR5⁺ cells which lead to cisplatin resistance in cervical cancer cells. DSF/Cu complex had the greater antitumor efficacy on cervical cancer than cisplatin in vitro and in vivo.

CONCLUSION

Our findings indicate that the cytotoxicity of DSF/Cu complex may be superior to cisplatin because of targeting LGR5-positive cervical cancer stem-like cells in cervical cancer. Thus, the DSF/Cu complex may represent a potential therapeutic strategy for cervical cancer patients.

The molecular underpinning of geminin-overexpressing triple-negative breast cancer cells homing specifically to lungs

Triple-negative breast cancer (TNBCs) display lung metastasis tropism. However, the mechanisms underlying this organ-specific pattern remains to be elucidated. We sought to evaluate the utility of blocking extravasation to prevent lung metastasis. To identify potential geminin overexpression-controlled genetic drivers that promote TNBC tumor homing to lungs, we used the differential/suppression subtractive chain (D/SSC) technique. A geminin overexpression-induced lung metastasis gene signature consists of 24 genes was discovered. We validated overexpression of five of these genes (LGR5, HAS2, CDH11, NCAM2, and DSC2) in worsening lung metastasis-free survival in TNBC patients. Our data demonstrate that LGR5-induced β-catenin signaling and stemness in TNBC cells are geminin-overexpression dependent. They also demonstrate for the first-time expression of RSPO2 in mouse lung tissue only and exacerbation of its secretion in the circulation of mice that develop geminin overexpressing/LGR5⁺-TNBC lung metastasis. We identified a novel extravasation receptor complex, consists of CDH11, CD44v6, c-Met, and AXL on geminin overexpressing/LGR5⁺-TNBC lung metastatic precursors, inhibition of any of its receptors prevented geminin overexpressing/LGR5⁺-TNBC lung metastasis. Overall, we propose that geminin overexpression in normal mammary epithelial (HME) cells promotes the generation of TNBC metastatic precursors that home specifically to lungs by upregulating LGR5 expression and promoting stemness, intravasation, and extravasation in these precursors. Circulating levels of RSPO2 and OPN can be diagnostic biomarkers to improve risk stratification of metastatic TNBC to lungs, as well as identifying patients who may benefit from therapy targeting geminin alone or in combination with any member of the newly discovered extravasation receptor complex to minimize TNBC lung metastasis.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

CD276 (B7H3) improve cancer stem cells formation in cervical carcinoma cell lines

Background

Cancer stem cells (CSCs) have been considered as a potential therapeutic target for cervical carcinoma. CD 276 is a well-known immune check point molecular, but its relationship with cervical CSCs was still unclear.

Methods

HeLa cell lines were obtained as cervical carcinoma in vitro model. HeLa cell Sphere formation culture was performed and CD276, OCT4 and SOX2 expression were determined by RT-qPCR. Transiently transfection and siRNA interference were used to modify CD276 expression. HeLa cell colony has been counted and cell proliferation was assessed by MTT assay. The relationship between CD276 and chemotherapy resistance of HeLa cell were evaluated by cisplatin treatment. Additionally, the mice model of xenograft tumor was established and CD276’s function was evaluated in vivo.

Results

Here, we demonstrate that the expression of CD276 is positively correlated with the amount of sphere-forming cells in HeLa cell lines. Overexpression of CD276 causes the inhibition of HeLa cells’ sphere formation, colony formation and cell viability. Meanwhile, the downregulation of CD276 leads to the other way. We also demonstrate that CD276 contributes to the chemotherapy resistance in the cell line. Furthermore, we verify the CD276’s function on HeLa xenotransplantation mice model.

Conclusions

These results suggest that CD276 elevates the self-renewal capacity of HeLa CSCs.

HNF4A Regulates the Proliferation and Tumor Formation of Cervical Cancer Cells through the Wnt/β-Catenin Pathway

Hepatocyte nuclear factor 4 alpha (HNF4A) is a transcriptional factor which plays an important role in the development of the liver, kidney, and intestines. Nevertheless, its role in cervical cancer and the underlying mechanism remain unknown. In this study, both immunohistochemistry and western blotting revealed that the expression of HNF4A was downregulated in cervical cancer. Xenograft assays suggested that HN4A could inhibit tumorigenic potential of cervical cancer in vivo. Functional studies illustrated that HNF4A also inhibited the proliferation and viability of cervical cancer cells in vitro. In addition, FACS analysis implied that HNF4A could induce cell cycle arrest from the G0/G1 phase to S phase. Further studies suggested that HNF4A downregulated the activity of the Wnt/β-catenin pathway. Altogether, our data demonstrated that HNF4A inhibited tumor formation and proliferation of cervical cancer cells through suppressing the activity of the Wnt/β-catenin pathway.

LRP5 promotes cancer stem cell traits and chemoresistance in colorectal cancer

The overactivation of canonical Wnt/β-catenin pathway and the maintenance of cancer stem cells (CSCs) are essential for the onset and malignant progression of most human cancers. However, their regulatory mechanism in colorectal cancer (CRC) has not yet been well demonstrated. Low-density lipoprotein receptor-related protein 5 (LRP5) has been identified as an indispensable co-receptor with frizzled family members for the canonical Wnt/β-catenin signal transduction. Herein, we show that activation of LRP5 gene promotes CSCs-like phenotypes, including tumorigenicity and drug resistance in CRC cells, through activating the canonical Wnt/β-catenin and IL-6/STAT3 signalling pathways. Clinically, the expression of LRP5 is upregulated in human CRC tissues and closely associated with clinical stages of patients with CRC. Further analysis showed silencing of endogenous LRP5 gene is sufficient to suppress the CSCs-like phenotypes of CRC through inhibiting these two pathways. In conclusion, our findings not only reveal a regulatory cross-talk between canonical Wnt/β-catenin signalling pathway, IL-6/STAT3 signalling pathway and CD133-related stemness that promote the malignant behaviour of CRC, but also provide a valuable target for the diagnosis and treatment of CRC.

The role of polyphenols in overcoming cancer drug resistance: a comprehensive review

Chemotherapeutic drugs are used to treat advanced stages of cancer or following surgery. However, cancers often develop resistance against drugs, leading to failure of treatment and recurrence of the disease. Polyphenols are a family of organic compounds with more than 10,000 members which have a three-membered flavan ring system in common. These natural compounds are known for their beneficial properties, such as free radical scavenging, decreasing oxidative stress, and modulating inflammation. Herein, we discuss the role of polyphenols (mainly curcumin, resveratrol, and epigallocatechin gallate [EGCG]) in different aspects of cancer drug resistance. Increasing drug uptake by tumor cells, decreasing drug metabolism by enzymes (e.g. cytochromes and glutathione-S-transferases), and reducing drug efflux are some of the mechanisms by which polyphenols increase the sensitivity of cancer cells to chemotherapeutic agents. Polyphenols also affect other targets for overcoming chemoresistance in cancer cells, including cell death (i.e. autophagy and apoptosis), EMT, ROS, DNA repair processes, cancer stem cells, and epigenetics (e.g. miRNAs).

A tumour-resident Lgr5+ stem-cell-like pool drives the establishment and progression of advanced gastric cancers

Gastric cancer is among the most prevalent and deadliest of cancers globally. To derive mechanistic insight into the pathways governing this disease, we generated a Claudin18-IRES-CreERT2 allele to selectively drive conditional dysregulation of the Wnt, Receptor Tyrosine Kinase and Trp53 pathways within the gastric epithelium. This resulted in highly reproducible metastatic, chromosomal-instable-type gastric cancer. In parallel, we developed orthotopic cancer organoid transplantation models to evaluate tumour-resident Lgr5⁺ populations as functional cancer stem cells via in vivo ablation. We show that Cldn18 tumours accurately recapitulate advanced human gastric cancer in terms of disease morphology, aberrant gene expression, molecular markers and sites of distant metastases. Importantly, we establish that tumour-resident Lgr5⁺ stem-like cells are critical to the initiation and maintenance of tumour burden and are obligatory for the establishment of metastases. These models will be invaluable for deriving clinically relevant mechanistic insights into cancer progression and as preclinical models for evaluating therapeutic targets.

Ubiquitin-conjugating enzyme E2T promotes tumor stem cell characteristics and migration of cervical cancer cells by regulating the GRP78/FAK pathway

Ubiquitin-conjugating enzyme E2T (UBE2T) functions as an E2 ubiquitin-conjugating enzyme in the ubiquitin-proteasome degradation system and mediates cellular processes, such as cell cycle, proliferation, and differentiation. UBE2T has been considered to be an oncogene in a variety of tumors. However, the oncogenic role of UBE2T in cervical cancer remains unclear. In this study, our results first showed that the expression of UBE2T was higher in both of cervical cancer tissues and cells than that in the normal tissues and cells. Knockdown of UBE2T reduced cervical cancer cell viability and suppressed the proliferation, invasion, and migration. However, overexpression of UBE2T contributed to cervical cancer cell growth and metastasis. Moreover, UBE2T overexpression cervical cancer cells demonstrated enhanced self-renewal capacity with upregulation of SOX2, Oct-4, and Nanog protein. Silencing of UBE2T downregulated protein expression of SOX2, Oct-4, and Nanog in cervical cancer cells reduced self-renewal capacity. Furthermore, ectopic UBE2T expression promoted protein expression of glucose-regulated protein 78 (GRP78) and focal adhesion kinase (FAK) phosphorylation in cervical cancer cells. The knockdown of UBE2T reduced protein expression of GRP78 and FAK phosphorylation. Collectively, UBE2T promoted cervical cancer stem cell traits and exerted an oncogenic role through activation of the GRP78/FAK pathway.

BAZ2A-mediated repression via H3K14ac-marked enhancers promotes prostate cancer stem cells

Prostate cancer (PCa) is one of the most prevalent cancers in men. Cancer stem cells are thought to be associated with PCa relapse. Here, we show that BAZ2A is required for PCa cells with a cancer stem‐like state. BAZ2A genomic occupancy in PCa cells coincides with H3K14ac‐enriched chromatin regions. This association is mediated by BAZ2A‐bromodomain (BAZ2A‐BRD) that specifically binds H3K14ac. BAZ2A associates with inactive enhancers marked by H3K14ac and repressing transcription of genes frequently silenced in aggressive and poorly differentiated PCa. BAZ2A‐mediated repression is also linked to EP300 that acetylates H3K14ac. BAZ2A‐BRD mutations or treatment with inhibitors abrogating BAZ2A‐BRD/H3K14ac interaction impair PCa stem cells. Furthermore, pharmacological inactivation of BAZ2A‐BRD impairs Pten‐loss oncogenic transformation of prostate organoids. Our findings indicate a role of BAZ2A‐BRD in PCa stem cell features and suggest potential epigenetic‐reader therapeutic strategies to target BAZ2A in aggressive PCa.

Messing Up the Cancer Stem Cell Chemoresistance Mechanisms Supported by Tumor Microenvironment

Despite the recent advances in cancer patient management and in the development of targeted therapies, systemic chemotherapy is currently used as a first-line treatment for many cancer types. After an initial partial response, patients become refractory to standard therapy fostering rapid tumor progression. Compelling evidence highlights that the resistance to chemotherapeutic regimens is a peculiarity of a subpopulation of cancer cells within tumor mass, known as cancer stem cells (CSCs). This cellular compartment is endowed with tumor-initiating and metastasis formation capabilities. CSC chemoresistance is sustained by a plethora of grow factors and cytokines released by neighboring tumor microenvironment (TME), which is mainly composed by adipocytes, cancer-associated fibroblasts (CAFs), immune and endothelial cells. TME strengthens CSC refractoriness to standard and targeted therapies by enhancing survival signaling pathways, DNA repair machinery, expression of drug efflux transporters and anti-apoptotic proteins. In the last years many efforts have been made to understand CSC-TME crosstalk and develop therapeutic strategy halting this interplay. Here, we report the combinatorial approaches, which perturb the interaction network between CSCs and the different component of TME.

The potential oncogenic and MLN4924-resistant effects of CSN5 on cervical cancer cells

Background

CSN5, a member of Cop9 signalosome, is essential for protein neddylation. It has been supposed to serve as an oncogene in some cancers. However, the role of CSN5 has not been investigated in cervical cancer yet.

Methods

Data from TCGA cohorts and GEO dataset was analyzed to examine the expression profile of CSN5 and clinical relevance in cervical cancers. The role of CSN5 on cervical cancer cell proliferation was investigated in cervical cancer cell lines, Siha and Hela, through CSN5 knockdown via CRISPR–CAS9. Western blot was used to detect the effect of CSN5 knockdown and overexpression. The biological behaviors were analyzed by CCK8, clone formation assay, 3-D spheroid generation assay and cell cycle assay. Besides, the role CSN5 knockdown in vivo was evaluated by xenograft tumor model. MLN4924 was given in Siha and Hela with CSN5 overexpression.

Results

We found that downregulation of CSN5 in Siha and Hela cells inhibited cell proliferation in vitro and in vivo, and the inhibitory effects were largely rescued by CSN5 overexpression. Moreover, deletion of CSN5 caused cell cycle arrest rather than inducing apoptosis. Importantly, CSN5 overexpression confers resistance to the anti-cancer effects of MLN4924 (pevonedistat) in cervical cancer cells.

Conclusions

Our findings demonstrated that CSN5 functions as an oncogene in cervical cancers and may serve as a potential indicator for predicting the effects of MLN4924 treatment in the future.

Insight into the role of multiple signaling pathways in regulating cancer stem cells of gynecologic cancers

Mounting evidence has demonstrated that a myriad of developmental signaling pathways, such as the Wnt, Notch, Hedgehog and Hippo, are frequently deregulated and play a critical role in regulating cancer stem cell (CSC) activity in human cancers, including gynecologic malignancies. In this review article, we describe an overview of various signaling pathways in human cancers. We further discuss the developmental roles how these pathways regulate CSCs from experimental evidences in gynecologic cancers. Moreover, we mention several compounds targeting CSCs in gynecologic cancers to enhance the treatment outcomes. Therefore, these signaling pathways might be the potential targets for developing targeted therapy in gynecologic cancers.

Fertility preservation in women with ovarian cancer: Finding new pathways: A case-control study

Background

Surgery and chemotherapy are the two most common treatments for cancers, including ovarian cancer. Although most ovarian cancers occur over the age of 45 yr, it may involve younger women and affect their reproductive ability.

Objective

To assess the expression of Leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5), Forkhead Box O1 (FOXO1), and miR-340 genes in the ovarian cancer tissues as well as ovarian cancer cell lines.

Materials and Methods

In this case-control study, 30 ovarian cancer samples (with the average age of 37 ± 2.5 years) coupled with their non-tumor marginal tissue (as a control) were collected. Proliferated cell lines were treated with several concentrations of cisplatin, and the half maximal inhibitory concentration (IC50) of cisplatin was quantified by MTT-assay. After RNA extraction, cDNA synthesis and qRT-PCR were done. Finally, the results were analyzed.

Results

While the expression levels of miR-340 and FOXO1 genes in tumor samples displayed a significant reduction (p ≤ 0.001), the LGR5 gene presented a significant increase in expression (p ≤ 0.0001). However, conversely, the expression levels of miR-340 and FOXO1 genes in cisplatin-sensitive cell lines, after 24, 48, and 72 hr of cisplatin treatment, indicated a significant increase (p ≤ 0.001) while the expression of LGR5 gene showed a significant decrease in the cisplatin-sensitive cell line (p < 0.05).

Conclusion

The LGR5, FOXO1, and miR-340 genes can be targeted for early diagnosis and more accurate treatment of ovarian cancer and may prevent some of the ovarian cancer complications such as infertility.

HOXB4 inhibits the proliferation and tumorigenesis of cervical cancer cells by downregulating the activity of Wnt/β-catenin signaling pathway

Homeobox B4 (HOXB4), which belongs to the homeobox (HOX) family, possesses transcription factor activity and has a crucial role in stem cell self-renewal and tumorigenesis. However, its biological function and exact mechanism in cervical cancer remain unknown. Here, we found that HOXB4 was markedly downregulated in cervical cancer. We demonstrated that HOXB4 obviously suppressed cervical cancer cell proliferation and tumorigenic potential in nude mice. Additionally, HOXB4-induced cell cycle arrest at the transition from the G0/G1 phase to the S phase. Conversely, loss of HOXB4 promoted cervical cancer cell growth both in vitro and in vivo. Bioinformatics analyses and mechanistic studies revealed that HOXB4 inhibited the activity of the Wnt/β-catenin signaling pathway by direct transcriptional repression of β-catenin. Furthermore, β-catenin re-expression rescued HOXB4-induced cervical cancer cell defects. Taken together, these findings suggested that HOXB4 directly transcriptional repressed β-catenin and subsequently inactivated the Wnt/β-catenin signaling pathway, leading to significant inhibition of cervical cancer cell growth and tumor formation.

LGR6 activates the Wnt/β-catenin signaling pathway and forms a β-catenin/TCF7L2/LGR6 feedback loop in LGR6high cervical cancer stem cells

The leucine-rich repeat-containing G-protein-coupled receptor 6 (LGR6) is considered to be a stem cell marker in many normal tissues and promotes tissue development, regeneration, and repair. LGR6 is also related to the initiation and progression of some malignant tumors. However, the role of LGR6 in cervical cancer has not been reported. Here, immunohistochemistry and western blotting showed that LGR6 was significantly upregulated in cervical cancer, compared with the normal cervix. By analyzing The Cancer Genome Atlas database, LGR6 was found to be correlated with a poor prognosis of cervical cancer. Then, a small population of LGR6^high cells isolated by using the fluorescence-activated cell sorting exhibited enhanced properties of cancer stem cells including self-renewal, differentiation, and tumorigenicity. Moreover, RNA sequencing revealed that LGR6 was correlated with the Wnt signaling pathway and TOP/FOP, reverse transcription-PCR, and western blotting further proved that LGR6 could activate the Wnt/β-catenin signaling pathway. Interestingly, LGR6 upregulated the expression of TCF7L2 by activating the Wnt/β-catenin pathway. Then, TCF7L2 combining with β-catenin in the nucleus enhanced LGR6 transcription by binding the promoter of LGR6, which further activated the Wnt signaling to form a positive feedback loop. Thus, our study demonstrated that LGR6 activated a novel β-catenin/TCF7L2/LGR6-positive feedback loop in LGR6^high cervical cancer stem cells (CSCs), which provided a new therapeutic strategy for targeting cervical CSCs to improve the prognosis of cervical cancer patients.

MiR-509-3p Induces Apoptosis and Affects the Chemosensitivity of Cervical Cancer Cells by Targeting the RAC1/PAK1/LIMK1/Cofilin Pathway

Chemoresistance is one of the main factors of treatment failure of cervical cancer (CC). Here, we intended to discover the role and mechanism of miR-509-5p in the paclitaxel chemoresistance of CC cells. RT-PCR was conducted to verify miR-509-3p expression. HCC94 and C-33A paclitaxel-resistant CC cell models were constructed. Additionally, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry were performed to verify the viability and apoptosis of HCC94 and C-33A cells after upregulating miR-509-3p. Besides, the downstream target of miR-509-3p was analyzed by bioinformatics, and the targeted relationship between miR-509-3p and RAC1 was identified by the dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Further, the expression of apoptotic proteins (Bcl2, Bax, and Caspase3) and the RAC1/PAK1/LIMK1/Cofilin pathway was monitored by Western blot. The result showed that upregulating miR-509-3p markedly inhibited the viability and promoted the apoptosis of CC cells. On the other hand, miR-509-3p was distinctly downregulated in paclitaxel-resistant HCC94 and C-33A cells (vs. normal cells). The transfection of miR-509-3p mimics notably increased their sensitivity to paclitaxel. Meanwhile, RAC1 was found as the potential target of miR-509-3p in bioinformatics analysis. Moreover, the RAC1/p21 (RAC1) activated kinase 1 (PAK1)/LIM kinase 1 (LIMK1)/Cofilin pathway was significantly activated in paclitaxel-resistant HCC94 and C-33A cells, while miR-509-3p overexpression significantly inactivated this pathway. Additionally, downregulation of RAC1 also partly reversed the paclitaxel-resistance of CC cells and inhibited PAK1/LIMK1/Cofilin. All in all, miR-509-3p enhances the apoptosis and chemosensitivity of CC cells by regulating the RAC1/PAK1/LIMK1/Cofilin pathway.

Wnt Signaling in the Tumor Microenvironment

Dysregulated Wnt signaling plays a central role in initiation, progression, and metastasis in many types of human cancers. Cancer development and resistance to conventional cancer therapies are highly associated with the tumor microenvironment (TME), which is composed of numerous stable non-cancer cells, including immune cells, extracellular matrix (ECM), fibroblasts, endothelial cells (ECs), and stromal cells. Recently, increasing evidence suggests that the relationship between Wnt signaling and the TME promotes the proliferation and maintenance of tumor cells, including leukemia. Here, we review the Wnt pathway, the role of Wnt signaling in different components of the TME, and therapeutic strategies for targeting Wnt signaling.

NF-YA promotes the cell proliferation and tumorigenic properties by transcriptional activation of SOX2 in cervical cancer

NF‐YA is considered as a crucial regulator for the maintenance of cancer stem cell (CSC) and involved in various types of malignant tumours. However, the exact function and molecular mechanisms of NF‐YA in the progression of cervical cancer remains poorly understood. Here, the expression of NF‐YA detected by immunohistochemistry was gradually increased from normal cervical tissues, to the high‐grade squamous intraepithelial lesions, and then to cervical cancer tissues. NF‐YA promoted the cell proliferation and tumorigenic properties of cervical cancer cells as well as tumorsphere formation and chemoresistance in vitro. The luciferase reporter assay combined with mutagenesis analyses and Western blotting showed that NF‐YA trans‐activated the expression of SOX2 in cervical cancer. Furthermore, quantitative chromatin immunoprecipitation (qChIP) and electrophoretic mobility shift assay (EMSA) confirmed that NF‐YA protein directly bound to the CCAAT box region located upstream of the SOX2 promoter. Together, our data demonstrated that NF‐YA was highly expressed in cervical cancer and promoted the cell proliferation, tumorigenicity and CSC characteristic by trans‐activating the expression of SOX2.

ALDH-1-positive cells exhibited a radioresistant phenotype that was enhanced with hypoxia in cervical cancer

BACKGROUND

We have previously found there was a small subpopulation of cells with cancer stem cell-like phenotype ALDH-1 in cervical cancer. Radiotherapy has been applied in most of the cervical cancer. However,the mechanisms underlying radioresistance still remained elusive. Our study is to explore whether ALDH+ cell promotes radioresistance by hypoxia.

METHODS

Cells were respectively cultured in hypoxia and normoxia environment and analyzed for marker stability, and cell cycle distribution.

RESULTS

Cell growth, apoptosis, cell cycle, sphere formation were affected by hypoxia. ALDH-1 and CHK2 were upregulated after hypoxia.

CONCLUSIONS

Here we show that ALDH-1 positive cells contribute to cervical carcinoma radioresistance through preferential activation of the DNA damage checkpoint response and an increase in DNA repair capacity. The fraction of these cells is enriched after radiation in cervical carcinoma.

Bioinformatics analysis and verification of molecular targets in ovarian cancer stem-like cells

BACKGROUND

Epithelial ovarian cancer (EOC) is a lethal and aggressive gynecological malignancy. Despite recent advances, existing therapies are challenged by a high relapse rate, eventually resulting in disease recurrence and chemoresistance. Emerging evidence indicates that a subpopulation of cells known as cancer stem-like cells (CSLCs) exists with non-tumorigenic cancer cells (non-CSCs) within a bulk tumor and is thought to be responsible for tumor recurrence and drug-resistance. Therefore, identifying the molecular drivers for cancer stem cells (CSCs) is critical for the development of novel therapeutic strategies for the treatment of EOC.

METHODS

Two gene datasets were downloaded from the Gene Expression Omnibus (GEO) database based on our search criteria. Differentially expressed genes (DEGs) in both datasets were obtained by the GEO2R web tool. Based on log2 (fold change) >2, the top thirteen up-regulated genes and log2 (fold change) < -1.5 top thirteen down-regulated genes were selected, and the association between their expressions and overall survival was analyzed by OncoLnc web tool. Gene Ontology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathways analysis, and protein-protein interaction (PPI) networks were performed for all the common DEGs found in both datasets. SK-OV-3 cells were cultured in an adherent culture medium and spheroids were generated in suspension culture with CSCs specific medium. RNA from both cell population was extracted to validate the selected DEGs expression by q-PCR. Growth inhibition assay was performed in SK-OV-3 cells after carboplatin treatment.

RESULTS

A total of 200 DEGs, 117 up-regulated and 83 down-regulated genes were commonly identified in both datasets. Analysis of pathways and enrichment tests indicated that the extracellular matrix part, cell proliferation, tissue development, and molecular function regulation were enriched in CSCs. Biological pathways such as interferon-alpha/beta signaling, molecules associated with elastic fibers, and synthesis of bile acids and bile salts were significantly enriched in CSCs. Among the top 13 up-regulated and down-regulated genes, MMP1 and PPFIBP1 expression were associated with overall survival. Higher expression of ADM, CXCR4, LGR5, and PTGS2 in carboplatin treated SK-OV-3 cells indicate a potential role in drug resistance.

CONCLUSIONS

The molecular signature and signaling pathways enriched in ovarian CSCs were identified by bioinformatics analysis. This analysis could provide further research ideas to find the new mechanism and novel potential therapeutic targets for ovarian CSCs.

Lgr5 maintains stemness and regulates cell property in nasopharyngeal carcinoma through Wnt/β-catenin signaling pathway

Nasopharyngeal carcinoma (NPC) is a common malignant tumor in Southern China and Southeast Asia. In this study, we found that Leucine rich repeat containing G protein-coupled receptor 5 (Lgr5) was highly expressed in NPC tissues and marked NPC stem cells. Lgr5high tumors showed differential transcriptional landscape compared to Lgr5not high tumors. Lgr5 expression was associated with the clinicopathologic features in NPC and was able to regulate the stemness and viability of NPC cell line CNE1 and HNE1. Meanwhile, the migration, invasion and epithelial-mesenchymal transition (EMT) was modulated by Lgr5 via Wnt/β-catenin signaling pathway. Furthermore, Lgr5 could regulate the sensitivity of NPC cells to chemotherapy drugs. Xenografted tumors from Lgr5-overexpressed CNE1 cells showed stronger tumor forming capacity and higher expression level of stem cell markers. Thus, we characterized previously unidentified role of Lgr5 in NPC cells, potential serving as a NPC stem cell biomarker and a therapeutic target against NPC.

Recent advances in the contribution of noncoding RNAs to cisplatin resistance in cervical cancer

Cervical cancer (CC) remains a major disease burden on the female population worldwide. Chemotherapy with cisplatin (cis-diamminedichloroplatinum (II); CDDP) and related drugs are the main treatment option for CC; however, their efficacy is limited by the development of drug resistance. Noncoding RNAs (ncRNAs) have been found to play critical roles in numerous physiological and pathological cellular processes, including drug resistance of cancer cells. In this review, we describe some of the ncRNAs, including miRNAs, lncRNAs and circRNAs, that are involved in the sensitivity/resistance of CC to CDDP-based chemotherapy and discuss their mechanisms of action. We also describe some ncRNAs that could be therapeutic targets to improve the sensitivity of CC to CDDP-based chemotherapy.

Characterization of iPS87, a prostate cancer stem cell-like cell line

Prostate cancer affects hundreds of thousands of men and families throughout the world. Although chemotherapy, radiation, surgery, and androgen deprivation therapy are applied, these therapies do not cure metastatic prostate cancer. Patients treated by androgen deprivation often develop castration resistant prostate cancer which is incurable. Novel approaches of treatment are clearly necessary. We have previously shown that prostate cancer originates as a stem cell disease. A prostate cancer patient sample, #87, obtained from prostatectomy surgery, was collected and frozen as single cell suspension. Cancer stem cell cultures were grown, single cell-cloned, and shown to be tumorigenic in SCID mice. However, outside its natural niche, the cultured prostate cancer stem cells lost their tumor-inducing capability and stem cell marker expression after approximately 8 transfers at a 1:3 split ratio. Tumor-inducing activity could be restored by inducing the cells to pluripotency using the method of Yamanaka. Cultures of human prostate-derived normal epithelial cells acquired from commercial sources were similarly induced to pluripotency and these did not acquire a tumor phenotype in vivo. To characterize the iPS87 cell line, cells were stained with antibodies to various markers of stem cells including: ALDH7A1, LGR5, Oct4, Nanog, Sox2, Androgen Receptor, and Retinoid X Receptor. These markers were found to be expressed by iPS87 cells, and the high tumorigenicity in SCID mice of iPS87 was confirmed by histopathology. This research thus characterizes the iPS87 cell line as a cancer-inducing, stem cell-like cell line, which can be used in the development of novel treatments for prostate cancer.

The Cancer Stem Cell in Hepatocellular Carcinoma

The recognition of intra-tumoral cellular heterogeneity has given way to the concept of the cancer stem cell (CSC). According to this concept, CSCs are able to self-renew and differentiate into all of the cancer cell lineages present within the tumor, placing the CSC at the top of a hierarchical tree. The observation that these cells—in contrast to bulk tumor cells—are able to exclusively initiate new tumors, initiate metastatic spread and resist chemotherapy implies that CSCs are solely responsible for tumor recurrence and should be therapeutically targeted. Toward this end, dissecting and understanding the biology of CSCs should translate into new clinical therapeutic approaches. In this article, we review the CSC concept in cancer, with a special focus on hepatocellular carcinoma.

Pterostilbene Suppresses both Cancer Cells and Cancer Stem-Like Cells in Cervical Cancer with Superior Bioavailability to Resveratrol

Increasing studies have reported that cancer stem cells (CSCs) play critical roles in therapeutic resistance, recurrence, and metastasis of tumors, including cervical cancer. Pterostilbene, a dimethylated derivative of resveratrol, is a plant polyphenol compound with potential chemopreventive activity. However, the therapeutic effect of pterostilbene against cervical CSCs remains unclear. In this study, we compared the anticancer effects of resveratrol and pterostilbene using both HeLa cervical cancer adherent and stem-like cells. Pterostilbene more effectively inhibited the growth and clonogenic survival, as well as metastatic ability of HeLa adherent cells than those of resveratrol. Moreover, the superior inhibitory effects of pterostilbene compared to resveratrol were associated with the enhanced activation of multiple mechanisms, including cell cycle arrest at S and G2/M phases, induction of ROS-mediated caspase-dependent apoptosis, and inhibition of matrix metalloproteinase (MMP)-2/-9 expression. Notably, pterostilbene exhibited a greater inhibitory effect on the tumorsphere-forming and migration abilities of HeLa cancer stem-like cells compared to resveratrol. This greater effect was achieved through more potent inhibition of the expression levels of stemness markers, such as CD133, Oct4, Sox2, and Nanog, as well as signal transducer and activator of transcription 3 signaling. These results suggest that pterostilbene might be a potential anticancer agent targeting both cancer cells and cancer stem-like cells of cervical cancer via the superior bioavailability to resveratrol.

Gastric squamous-columnar junction contains a large pool of cancer-prone immature osteopontin responsive Lgr5-CD44+ cells

Areas of a junction between two types of epithelia are known to be cancer-prone in many organ systems. However, mechanisms for preferential malignant transformation at the junction areas remain insufficiently elucidated. Here we report that inactivation of tumor suppressor genes Trp53 and Rb1 in the gastric squamous-columnar junction (SCJ) epithelium results in preferential formation of metastatic poorly differentiated neoplasms, which are similar to human gastroesophageal carcinoma. Unlike transformation-resistant antral cells, SCJ cells contain a highly proliferative pool of immature Lgr5⁻CD44⁺ cells, which are prone to transformation in organoid assays, comprise early dysplastic lesions, and constitute up to 30% of all neoplastic cells. CD44 ligand osteopontin (OPN) is preferentially expressed in and promotes organoid formation ability and transformation of the SCJ glandular epithelium. OPN and CD44 overexpression correlate with the worst prognosis of human gastroesophageal carcinoma. Thus, detection and selective targeting of the active OPN-CD44 pathway may have direct clinical relevance.

Cancers arising from the gastric squamous-columnar junction have high incidence and are characterized by a poor prognosis. Here, the authors use genetic mouse models to show that loss of p53 and Rb1 expression results in preferential tumour development at the gastric squamous-columnar junction that contains a large pool of osteopontin responsive Lgr5-CD44+ cells.

BET and Aurora Kinase A inhibitors synergize against MYCN-positive human glioblastoma cells

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor in adults. Patients usually undergo surgery followed by aggressive radio- and chemotherapy with the alkylating agent temozolomide (TMZ). Still, median survival is only 12–15 months after diagnosis. Many human cancers including GBMs demonstrate addiction to MYC transcription factor signaling and can become susceptible to inhibition of MYC downstream genes. JQ1 is an effective inhibitor of BET Bromodomains, a class of epigenetic readers regulating expression of downstream MYC targets. Here, we show that BET inhibition decreases viability of patient-derived GBM cell lines. We propose a distinct expression signature of MYCN-elevated GBM cells that correlates with significant sensitivity to BET inhibition. In tumors showing JQ1 sensitivity, we found enrichment of pathways regulating cell cycle, DNA damage response and repair. As DNA repair leads to acquired chemoresistance to TMZ, JQ1 treatment in combination with TMZ synergistically inhibited proliferation of MYCN-elevated cells. Bioinformatic analyses further showed that the expression of MYCN correlates with Aurora Kinase A levels and Aurora Kinase inhibitors indeed showed synergistic efficacy in combination with BET inhibition. Collectively, our data suggest that BET inhibitors could potentiate the efficacy of either TMZ or Aurora Kinase inhibitors in GBM treatment.

Cervical cancer stem cells and other leading factors associated with cervical cancer development

Cervical cancer (CC) is one of the leading causes of cancer-associated mortalities in women from developing countries. Similar to other types of cancer, CC is considered to be a multifactorial disease, involving socioeconomic, cultural, immunological and epigenetic factors, as well as persistent human papilloma virus (HPV) infection. It has been well established that cancer stem cells (CSCs) play an important role in defining tumor size, the speed of development and the level of regression following treatment; therefore, CSCs are associated with a poor prognosis. CSCs have been detected in many types of cancer, including leukemia, pancreatic, colon, esophagus, liver, prostate, breast, gastric and lung cancer. In cervical cancer, CSCs have been associated with resistance to normally used drugs such as cisplatin. The present review summarizes the strategies that high-risk HPV viruses (HPV-16 and HPV-18) have developed to transform normal epithelial cells into cancer cells, as well as the cellular pathways and studies associated with the identification of cervical cancer stem cell biomarkers. In this sense, the present review provides state of the art information regarding CC development.

Enhancement of cisplatin-induced cytotoxicity against cervical cancer spheroid cells by targeting long non-coding RNAs

Cervical cancer (CVC) is one of the most common types of gynecologic malignant tumor in the world. Unfortunately, current treatments including chemo-/radiotherapy still show the limitation on CVC progress. It is well known that cancer stem cells (CSCs) plays a critical role in drug resistance and metastasis. Furthermore, dysregulation of long non-coding RNA (LncRNA) shows close association to tumorigenesis and development of multiple cancers. In this study, we investigated the cytotoxic effect of cisplatin, a clinical chemotherapeutic for cervical cancer treatment, on parental and spheroid CVC cells and surveyed the effect of LncRNA on drug-resistance. We found that spheroid CVC cells showed much more resistant to cisplatin-induced cytotoxicity compared with parental CVC cells. Furthermore, cisplatin significantly induced apoptotic cell death, while it induced cell cycle arrest in G0/G1 phase at the same dose (10 μg/ml). We also found the significant expression of EGFR in spheroid instead of parental CVC cells. Interestingly, we revealed that protruding target lncRNAs were up-regulated in cisplatin-treated spheroid CVC cells, and inhibition of these lncRNAs enhanced the cytotoxicity of cisplatin against spheroid CVC cells. These data suggest that LncRNA might act as a critical modulator on drug-resistant capability of cervical CSCs and would be a novel target for cervical cancer treatment.

Role and molecular mechanism of stem cells in colorectal cancer initiation

In recent years, the rate of colorectal cancer has sharply increased, especially in China, where it ranks second for the number of cancer fatalities. Currently, the treatment of colorectal cancer patients involves the combination of resection surgery and treatment with postoperative anticancer drugs such as 5-FU and oxaliplatin. However, recurrence and metastasis after treatment are still the dominant reasons for the low survival rate. Colorectal cancer stem cells (CSCs) are regarded as the key contributors to tumour recurrence and metastasis due to their resistance to chemotherapy drugs and their extremely high tumourigenicity. Once CSCs overcome chemotherapy treatment, they continue to survive and reinitiate proliferation to form tumours, leading to recurrence. The dominant reason for CSC resistance is that most anticancer drugs are aimed at inhibiting proliferative pathways in cancer cells that differ from those in CSCs. Therefore, studies on the characteristics of CSCs and their intracellular molecular pathways are essential for the exploration of CSC-targeted drugs. In this report, we review recent advances in the research of CSCs and, in particular, review the important intracellular molecular pathways, such as HOXA5-catenin, STRAP-NOTCH and YAP/TAZ, related to the maintenance and differentiation of stem cells to generate a theoretical basis for the exploration of CSC-targeted drugs.

Cancer Stem Cells in Neuroblastoma: Expanding the Therapeutic Frontier

Neuroblastoma (NB) is the most common extracranial solid tumor often diagnosed in childhood. Despite intense efforts to develop a successful treatment, current available therapies are still challenged by high rates of resistance, recurrence and progression, most notably in advanced cases and highly malignant tumors. Emerging evidence proposes that this might be due to a subpopulation of cancer stem cells (CSCs) or tumor-initiating cells (TICs) found in the bulk of the tumor. Therefore, the development of more targeted therapy is highly dependent on the identification of the molecular signatures and genetic aberrations characteristic to this subpopulation of cells. This review aims at providing an overview of the key molecular players involved in NB CSCs and focuses on the experimental evidence from NB cell lines, patient-derived xenografts and primary tumors. It also provides some novel approaches of targeting multiple drivers governing the stemness of CSCs to achieve better anti-tumor effects than the currently used therapeutic agents.

Overexpression of LGR-5 as a Predictor of Poor Outcome in Patients with Hepatocellular Carcinoma

Hepatocarcinogenesis and distant metastasis pose major challenges for physicians. They are regulated by several genes, such as AKT, JUK, Wnt, and P53, and their expression activates several important processes such as cell proliferation, migration, motility, and interaction in the microenvironment. The leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR-5) is a novel biomarker, particularly in stem cells, and is involved in embryogenesis, tumor development, and tumor cell signal transduction. Here, we investigated LGR-5 expression using immunohistochemistry and analyzed the correlation between clinical features and prognosis in patients with hepatocellular carcinoma (HCC). We found that LGR-5 expression was higher in tumor tissues than in normal liver tissues, and that high LGR-5 expression possibly favored poor outcomes in HCC, especially in well/moderate differentiation grade, hepatitis C virus (HCV)-negative, and hepatitis B virus (HBV)-positive groups. Thus, the LGR-5 marker is suggested to be a routine biomarker for poor prognosis, thereby providing a platform for anti-LGR-5-targeted therapy in the future.

KRT17 confers paclitaxel-induced resistance and migration to cervical cancer cells

AIM

To understand potential pro-oncological effects of lower dose paclitaxel treatment in cervical cancer cells, we investigated the potential roles of KRT17 on migration and proliferation of cervical cancer cells which might respond to cytoskeletal-based drugs treatments.

MATERIALS AND METHODS

We extracted the clinic data of cervical cancer patients from TCGA database to investigate mRNA expression of different keratins. HPV genotypes were identified by reverse transcription PCR. krt17 mRNA and EMT markers were quantified by real-time PCR. krt17 and EMT markers protein were immunoblotted by western blot. Cell viability was detected by CCK8. Cell migration was performed by transwell migration assay.

KEY FINDINGS

Our results showed that HPV16 infection correlated with the expression of KRT17 in cervical cancer cell lines. KRT17 knockdown would decrease Snail2 and elevate E-Cadherin to inhibit migration of Caski cells and SiHa cells. Lower dose of paclitaxel promoted SiHa proliferation, it also significantly promoted the migration of Caski cells. Otherwise, colchicine and higher dose of paclitaxel dose-dependently suppressed the proliferation and migration of Caski cells and SiHa cells. Moreover, KRT17 knockdown significantly facilitated cytoskeletal-based drugs to inhibit migration and induce cytotoxicity in cervical cancer cells.

SIGNIFICANCE

KRT17 played pivotal oncogenic roles in cell survival, migration and paclitaxel-induced resistance of cervical cancer cells. Thus, KRT17 would serve as a promising target for compromising paclitaxel-induced resistance and metastasis.

Depletion of death-associated protein-3 induces chemoresistance in gastric cancer cells through the β-catenin/LGR5/Bcl-2 axis

Previously, we demonstrated that death-associated protein-3 (DAP3) loss drives chemoresistance in gastric cancer cells. In the present study, we aimed to determine the underlying molecular mechanism. The effect of DAP3 silencing on β-catenin signaling was assessed. The direct mediator of DAP3 silencing-induced chemoresistance was identified. Depletion of DAP3 stimulates nuclear accumulation of β-catenin and enhances β-catenin-dependent transcriptional activity in gastric cancer cells. However, the protein kinase B , , extracellular regulated protein kinase and signal transducer and activator of transcription 3 signaling pathways remain unaffected by DAP3 loss. We found that the downstream target gene LGR5 (leucine-rich G-protein coupled receptor 5) is upregulated in DAP3-depleted gastric cancer cells. Moreover, knockdown of LGR5 resensitizes DAP3-depleted gastric cancer cells to 5-fluorouracil (5-FU) and oxaliplatin. We also observed that ectopic expression of LGR5 reduces apoptosis in gastric cancer cells on treatment with 5-FU and oxaliplatin, which is accompanied by prevention of caspase-3 cleavage. The antiapoptotic protein Bcl-2 is identified as a key mediator of LGR5-induced apoptosis resistance in gastric cancer cells. The present findings indicate that DAP3 deficiency-induced chemoresistance in gastric cancer is at least partially mediated through the β-catenin/LGR5/Bcl-2 axis. Targeting LGR5 may provide a novel strategy to overcome chemoresistance in DAP3-deficient gastric cancer cells.