Ideal sphere-forming culture conditions to maintain pluripotency in a hepatocellular carcinoma cell lines

Unveiling IL6R and MYC as Targeting Biomarkers in Imatinib-Resistant Chronic Myeloid Leukemia through Advanced Non-Invasive Apoptosis Detection Sensor Version 2 Detection

The management of chronic myelogenous leukemia (CML) has seen significant progress with the introduction of tyrosine kinase inhibitors (TKIs), particularly Imatinib. However, a notable proportion of CML patients develop resistance to Imatinib, often due to the persistence of leukemia stem cells and resistance mechanisms independent of BCR::ABL1 This study investigates the roles of IL6R, IL7R, and MYC in Imatinib resistance by employing CRISPR/Cas9 for gene editing and the Non-Invasive Apoptosis Detection Sensor version 2 (NIADS v2) for apoptosis assessment. The results indicate that Imatinib-resistant K562 cells (K562-IR) predominantly express IL6R, IL7R, and MYC, with IL6R and MYC playing crucial roles in cell survival and sensitivity to Imatinib. Conversely, IL7R does not significantly impact cytotoxicity, either alone or in combination with Imatinib. Further genetic editing experiments confirm the protective functions of IL6R and MYC in K562-IR cells, suggesting their potential as therapeutic targets for overcoming Imatinib resistance in CML. This study contributes to understanding the mechanisms of Imatinib resistance in CML, proposing IL6R and MYC as pivotal targets for therapeutic strategies. Moreover, the utilization of NIADS v2 enhances our capability to analyze apoptosis and drug responses, contributing to a deeper understanding of CML pathogenesis and treatment options.

Influence of extracellular matrix composition on tumour cell behaviour in a biomimetic in vitro model for hepatocellular carcinoma

The tumor micro-environment (TME) of hepatocellular carcinoma (HCC) consists out of cirrhotic liver tissue and is characterized by an extensive deposition of extracellular matrix proteins (ECM). The evolution from a reversible fibrotic state to end-stage of liver disease, namely cirrhosis, is characterized by an increased deposition of ECM, as well as changes in the exact ECM composition, which both contribute to an increased liver stiffness and can alter tumor phenotype. The goal of this study was to assess how changes in matrix composition and stiffness influence tumor behavior. HCC-cell lines were grown in a biomimetic hydrogel model resembling the stiffness and composition of a fibrotic or cirrhotic liver. When HCC-cells were grown in a matrix resembling a cirrhotic liver, they increased proliferation and protein content, compared to those grown in a fibrotic environment. Tumour nodules spontaneously formed outside the gels, which appeared earlier in cirrhotic conditions and were significantly larger compared to those found outside fibrotic gels. These tumor nodules had an increased expression of markers related to epithelial-to-mesenchymal transition (EMT), when comparing cirrhotic to fibrotic gels. HCC-cells grown in cirrhotic gels were also more resistant to doxorubicin compared with those grown in fibrotic gels or in 2D. Therefore, altering ECM composition affects tumor behavior, for instance by increasing pro-metastatic potential, inducing EMT and reducing response to chemotherapy.

The Role of Cancer Stem Cells and Their Extracellular Vesicles in the Modulation of the Antitumor Immunity

Cancer stem cells (CSCs) are a population of tumor cells that share similar properties to normal stem cells. CSCs are able to promote tumor progression and recurrence due to their resistance to chemotherapy and ability to stimulate angiogenesis and differentiate into non-CSCs. Cancer stem cells can also create a significant immunosuppressive environment around themselves by suppressing the activity of effector immune cells and recruiting cells that support tumor escape from immune response. The immunosuppressive effect of CSCs can be mediated by receptors located on their surface, as well as by secreted molecules, which transfer immunosuppressive signals to the cells of tumor microenvironment. In this article, the ability of CSCs to regulate the antitumor immune response and a contribution of CSC-derived EVs into the avoidance of the immune response are discussed.

PLGA-nano-encapsulated Disulfiram inhibits hypoxia-induced NFκB, cancer stem cells and targets glioblastoma in vitro and in vivo

Glioblastoma stem cell (GSC) is the major cause of glioblastoma multiforme (GBM) chemotherapy failure. Hypoxia is one of the determinants of GSC. NFκB plays a pivotal link between hypoxia and cancer stem cells (CSCs). Disulfiram (DS), an antialcoholism drug, has very strong NFκB-inhibiting and anti-CSC activity. In this study, the in vitro anti-GSC activity of DS and in vivo anti-GBM efficacy of poly lactic-co-glycolic acid nanoparticle-encapsulated DS (DS-PLGA) were examined. We attempt to elucidate the molecular network between hypoxia and GSCs, and also examined the anti-GSC activity of DS in vitro and in vivo. The influence of GSCs and hypoxia on GBM chemoresistance and invasiveness was studied in hypoxic and spheroid cultures. The molecular regulatory roles of NFκB, HIF1α and HIF2α were investigated using stably transfected U373MG cell lines. The hypoxia in neurospheres determines the cancer stem cell characters of the sphere-cultured GBM cell lines (U87MG, U251MG, U373MG). NFκB is located at a higher hierarchical position than HIF1α/HIF2α in hypoxic regulatory network and plays a key role in hypoxia-induced GSC characters. DS inhibits NFκB activity and targets hypoxia-induced GSCs. It showed selective toxicity to GBM cells, eradicates GSC and blocks migration and invasion at very low concentrations. DS-PLGA efficaciously inhibits orthotopic and subcutaneous U87MG xenograft in mouse models with no toxicity to vital organs.

SNU-333 Cells as an Appropriate Cell Line for the Orthotopic Renal Cell Carcinoma Model

Objective: To investigate a feasible candidate for an appropriate cell line for the orthotopic renal cell carcinoma (RCC) model. Methods: Normal human proximal tubule cells (HK-2) and RCC cells were used for MTT assay, Western blotting, sphere-forming assay, and orthotopic injection of BALB/c-nude mice. Immunohistochemistry was adopted in tissue arrays and orthotopic tumors. Results: Primary RCC cells showed resistance to a GPX4 inhibitor compared to HK-2 and to metastatic RCC cells, Caki-1. Caki-2 and SNU-333 cells showed resistance to ferroptosis via increased GPX4 and FTH1, respectively. RCC cells showed increased αSMA, in which Caki-2 and SNU-333 cells exhibited different epithelial–mesenchymal transition and cancer stem cell markers. Caki-1 and SNU-333 cells formed spheres in vitro and orthotopic tumor masses in vivo. The injected SNU-333 tumor only showed high intensities of CD10 and PAX8, markers of renal origin. Conclusion: SNU-333 cell line exhibited resistance via iron metabolism and stemness, and had tumor-initiating capacities in vitro and in vivo. These results suggest that among the cells tested, SNU-333 cells were the most promising for the establishment of an orthotopic RCC model for further researches.

SNAIL regulates gastric carcinogenesis through CCN3 and NEFL

Among cancer cells, there are specific cell populations of whose activities are comparable to those of stem cells in normal tissues, and for whom the levels of cell dedifferentiation are reported to correlate with poor prognosis. Information concerning the mechanisms that modulate the stemness like traits of cancer cells is limited. Therefore, we examined five gastric cancer cell lines and isolated gastric oncospheres from three gastric cancer cell lines. The gastric cancer cells that expanded in the spheres expressed relatively elevated proportion of CD44, which is a marker of gastric cancer stem cells (CSCs), and displayed many properties of CSCs, for example: chemoresistance, tumorigenicity and epithelial-mesenchymal transition (EMT) acquisition. SNAIL, which is a key factor in EMT, was highly expressed in the gastric spheres. Microarray analysis in gastric cancer cell line HGC27 showed that CCN3 and NEFL displayed the greatest differential expression by knocking down of SNAIL; the former was upregulated and the latter downregulated, respectively. Downregulation of CCN3 and upregulation of NEFL gene expression impaired the SNAIL-dependent EMT activity: high tumorigenicity, and chemoresistance in gastric cancer cells. Thus, approach that disrupts SNAIL/CCN3/NEFL axis may be credible in inhibiting gastric cancer development.

Dual Targeting of Sorafenib-Resistant HCC-Derived Cancer Stem Cells

Sorafenib, an oral multi-tyrosine kinase inhibitor, has been the first-line therapy for the treatment of patients with advanced HCC, providing a survival benefit of only three months in approximately 30% of patients. Cancer stem cells (CSCs) are a rare tumour subpopulation with self-renewal and differentiation capabilities, and have been implicated in tumour growth, recurrence and drug resistance. The process of epithelial-to-mesenchymal transition (EMT) contributes to the generation and maintenance of the CSC population, resulting in immune evasion and therapy resistance in several cancers, including HCC. The aim of this study is to target the chemoresistant CSC population in HCC by assessing the effectiveness of a combination treatment approach with Sorafenib, an EMT inhibitor and an immune checkpoint inhibitor (ICI). A stem-cell-conditioned serum-free medium was utilised to enrich the CSC population from the human HCC cell lines Hep3B, PLC/PRF/5 and HepG2. The anchorage independent spheres were characterised for CSC features. The human HCC-derived spheres were assessed for EMT status and expression of immune checkpoint molecules. The effect of combination treatment with SB431542, an EMT inhibitor, and siRNA-mediated knockdown of programmed cell death protein ligand-1 (PD-L1) or CD73 along with Sorafenib on human HCC-derived CSCs was examined with cell viability and apoptosis assays. The three-dimensional spheres enriched from human HCC cell lines demonstrated CSC-like features. The human HCC-derived CSCs also exhibited the EMT phenotype along with the upregulation of immune checkpoint molecules. The combined treatment with SB431542 and siRNA-mediated PD-L1 or CD73 knockdown effectively enhanced the cytotoxicity of Sorafenib against the CSC population compared to Sorafenib alone, as evidenced by the reduced size and proliferation of spheres. Furthermore, the combination treatment of Sorafenib with SB431542 and PD-L1 or CD73 siRNA resulted in an increased proportion of an apoptotic population, as evidenced by flow cytometry analysis. In conclusion, the combined targeting of EMT and immune checkpoint molecules with Sorafenib can effectively target the CSC tumour subpopulation.

Vitexin attenuates epithelial ovarian cancer cell viability and motility in vitro and carcinogenesis in vivo via p38 and ERK1/2 pathways related VEGFA

Background

Epithelial ovarian cancer (EOC) is the most common type of ovarian tumor, however, effective treatment does not currently exist for this condition. This study evaluated the role of vitexin in mitigating EOC both in vitro and in vivo.

Method

SKOV-3 cells were used for in vitro experimentation. Xenotransplantation mouse models were set up by subcutaneously injecting mice with SKOV-3 cells. CCK8 was used to screen the optimal dose in vitro. Cell proliferation, invasion, number of microtubule nodules and apoptosis were respectively detected by colony formation assay, transwell assay, microtubule formation assay and flow cytometry. TUNEL and immunohistochemistry were used to detect tissues apoptosis and VEGF content. Western blot assay was used to detect the expression of Ki67, caspase-3, VEGFA, VEGFR2, ERK1/2 and p38.

Results

In vitro experiment, compared with the control group, 10 µL of vitexin significantly reduced Ki67 levels and enhanced tumor cell apoptosis rate. Additionally, the colony forming rate, invasive cells per field, and number of nodes/HPF in vitexin treated group decreased dramatically. The result of western blot showed that levels of p-p38/p38 and p-ERK1/2/ERK1/2 also noticeably decreased. In vivo experiment, 40 mg/kg of vitexin significantly inhibited tumor growth. In addition, vitexin significantly enhanced the percentage of tissues apoptosis, which was accompanied by a decrease in the percentage of VEGF-positive cells.

Conclusions

Vitexin decreased the proliferation and invasion of SKOV-3 cells and noticeably reduced tumor growth. These findings suggest that vitexin could be a promising therapy for EOC.

Metastatic renal cell carcinoma cells growing in 3D on poly‑D‑lysine or laminin present a stem‑like phenotype and drug resistance

3D spheroids are built by heterogeneous cell types in different proliferative and metabolic states and are enriched in cancer stem cells. The main aim of the study was to investigate the usefulness of a novel metastatic renal cell carcinoma (RCC) 3D spheroid culture for in vitro cancer stem cell physiology research and drug toxicity screening. RCC cell lines, Caki-1 (skin metastasis derived) and ACHN (pleural effusion derived), were efficiently cultured in growth-factor/serum deprived, defined, StemXvivo and Nutristem medium on laminin-coated or poly-D-lysine-coated plates. In optimal 3D culture conditions, ACHN cells (StemXVivo/poly-D-lysine) formed small spheroids with remaining adherent cells of an epithelial phenotype, while Caki-1 cells (StemXVivo/laminin) formed large dark spheroids with significantly reduced cell viability in the center. In the 3D structures, expression levels of genes encoding stem transcription factors (OCT4, SOX2, NES) and RCC stem cell markers (CD105, CD133) were deregulated in comparison to these expression levels in traditional 2D culture. Sunitinib, epirubicin and doxycycline were more toxic to cells cultured in monolayers than for cells in 3D spheroids. High numbers of cells arrested in the G0/G1 phase of the cell cycle were found in spheroids under sunitinib treatment. We showed that metastatic RCC 3D spheroids supported with ECM are a useful model to determine the cancer cell growth characteristics that are not found in adherent 2D cultures. Due to the more complex architecture, spheroids may mimic in vivo micrometastases and may be more appropriate to investigate novel drug candidate responses, including the direct effects of tyrosine kinase inhibitor activity against RCC cells.

Salivary gland cell aggregates are derived from self-organization of acinar lineage cells

OBJECTIVE

The objective of this study was to characterize the mechanism by which salivary gland cells (SGC) aggregate in vitro.

DESIGN

Timelapse microscopy was utilized to analyze the process of salivary gland aggregate formation using both primary murine and human salivary gland cells. The role of cell density, proliferation, extracellular calcium, and secretory acinar cells in aggregate formation was investigated. Finally, the ability of cells isolated from irradiated glands to form aggregates was also evaluated.

RESULTS

Salivary gland cell self-organization rather than proliferation was the predominant mechanism of aggregate formation in both primary mouse and human salivary gland cultures. Aggregation was found to require extracellular calcium while acinar lineage cells account for ∼80% of the total aggregate cell population. Finally, aggregation was not impaired by irradiation.

CONCLUSIONS

The data reveal that aggregation occurs as a result of heterogeneous salivary gland cell self-organization rather than from stem cell proliferation and differentiation, contradicting previous dogma. These results suggest a re-evaluation of aggregate formation as a criterion defining salivary gland stem cells.

The Chinese medicine Chai Hu Li Zhong Tang protects against non-alcoholic fatty liver disease by activating AMPKα

An effective treatment for non-alcoholic fatty liver disease (NAFLD) is urgently needed. In the present study, we investigated whether the Chinese medicine Chai Hu Li Zhong Tang (CHLZT) could protect against the development of NAFLD. Rats in an animal model of NAFLD were treated with CHLZT, and their serum levels of cholesterol (TC), triglycerides (TG), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were detected with an automatic biochemical analyzer. A cellular model of NAFLD was also established by culturing HepG2 cells in a medium that contained a long chain fat emulsion. Those cells were treated with CHLZT that contained serum from rats. After treatment, the levels of adenylate-activated protein kinase (AMPK) α (AMPKα), p-AMPKα, acetyl coenzyme A carboxylase (ACC) α (ACCα), pACCα, PPARγ, and SREBP-2 were detected. The AMPK agonist, acadesine (AICAR), was used as a positive control compound. Our results showed that CHLZT or AICAR significantly decreased the serum levels of TG, TC, LDL-C, AST, ALT, and insulin in NAFLD rats, and significantly increased their serum HDL-C levels. Treatments with CHLZT or AICAR significantly decreased the numbers of lipid droplets in NAFLD liver tissues and HepG2 cells. CHLZT and AICAR increased the levels of p-AMPKα and PPARγ in the NAFLD liver tissues and HepG2 cells, but decreased the levels of ACC-α, p-ACC-α, SREBP-2, and 3-hydroxyl-3-methylglutaryl-coenzyme A reductase (HMGR). CHLZT protects against NAFLD by activating AMPKα, and also by inhibiting ACC activity, down-regulating SREBP2 and HMGR, and up-regulating PPAR-γ. Our results suggest that CHLZT might be useful for treating NAFLD in the clinic.

Yes-associated protein/TEA domain family member and hepatocyte nuclear factor 4-alpha (HNF4α) repress reciprocally to regulate hepatocarcinogenesis in rats and mice

Great progress has been achieved in the study of Hippo signaling in regulating tumorigenesis; however, the downstream molecular events that mediate this process have not been completely defined. Moreover, regulation of Hippo signaling during tumorigenesis in hepatocellular carcinoma (HCC) remains largely unknown. In the present study, we systematically investigated the relationship between Yes-associated protein/TEA domain family member (YAP-TEAD) and hepatocyte nuclear factor 4-alpha (HNF4α) in the hepatocarcinogenesis of HCC cells. Our results indicated that HNF4α expression was negatively regulated by YAP1 in HCC cells by a ubiquitin proteasome pathway. By contrast, HNF4α was found to directly associate with TEAD4 to compete with YAP1 for binding to TEAD4, thus inhibiting the transcriptional activity of YAP-TEAD and expression of their target genes. Moreover, overexpression of HNF4α was found to significantly compromise YAP-TEAD-induced HCC cell proliferation and stem cell expansion. Finally, we documented the regulatory mechanism between YAP-TEAD and HNF4α in rat and mouse tumor models, which confirmed our in vitro results.

CONCLUSION

There is a double-negative feedback mechanism that controls TEAD-YAP and HNF4α expression in vitro and in vivo, thereby regulating cellular proliferation and differentiation. Given that YAP acts as a dominant oncogene in HCC and plays a crucial role in stem cell homeostasis and tissue regeneration, manipulating the interaction between YAP, TEADs, and HNF4α may provide a new approach for HCC treatment and regenerative medicine. (Hepatology 2017;65:1206-1221).

MiR-15a suppresses hepatocarcinoma cell migration and invasion by directly targeting cMyb

PURPOSE

This study aimed to determine the function of miR-15a in HCC, and identify cMyb as a target of miR-15a.

METHODS

RNA expression was evaluated by quantitative real-time PCR (qRT-PCR). The effects of miR-15a or cMyb on HCC cells were evaluated by transwell migration assay and western blot analysis. CMyb, the predicted target, has been frequently verified by luciferase assay.

RESULTS

MiR-15a was markedly downregulated in sphere culture HCC cells by qRT-PCR. CMyb was predicted to be a potential target of miR-15a using bioinformatics analysis. This prediction has been frequently verified by luciferase assay and western blot. A positive correlation between cMyb and the migration ability of HCC cells was demonstrated by transwell assays. MiR-15a mimic suppressed cMyb expression to weaken HCC cell migration ability. On the other hand, miR-15a inhibitor upregulated cMyb and induced HCC cell migration.

CONCLUSION

MiR-15a could suppress HCC progression through the repression of cMyb, making miR-15a a potential therapeutic target.

Influence of TP53 and CDH1 genes in hepatocellular cancer spheroid formation and culture: a model system to understand cancer cell growth mechanics

Background

Spheroid based culture methods are gaining prominence to elucidate the role of the microenvironment in liver carcinogenesis. Additionally, the phenomenon of epithelial-mesenchymal transition also plays an important role in determining the metastatic potential of liver cancer. Tumor spheroids are thus important models to understand the basic biology of liver cancer.

Methods

We cultured, characterized and examined the formation of compact 3-D micro-tumor spheroids in five hepatocellular carcinoma (HCC) cell lines, each with differing TP53 mutational status (wt vs mutant vs null). Spheroid viability and death was systematically measured over a course of a 10 day growth period using various assays. We also examined the TP53 and E-cadherin (CDH1) mRNA and protein expression status in each cell line of the 2-D and 3-D cell models.

Results

A novel finding of our study was the identification of variable 3-D spheroid morphology in individual cell lines, ranging from large and compact, to small and unstable spheroid morphologies. The observed morphological differences between the spheroids were robust and consistent over the duration of spheroid culture growth of 10 days in a repeatable manner. Highly variable CDH1 expression was identified depending on the TP53 mutational status of the individual HCC cell line, which may explain the variable spheroid morphology. We observed consistent patterns of TP53 and CDH1 expression in both 2-D and 3-D culture models.

Conclusions

In conclusion, we show that 3-D spheroids are a useful model to determine the morphological growth characteristics of cell lines which are not immediately apparent in routine 2-D culture methods. 3-D culture methods may provide a better alternative to study the process of epithelial-mesenchymal transition (EMT) which is important in the process of liver cancer metastasis.