Hepatocyte growth factor and inducible nitric oxide synthase are involved in multidrug resistance-induced angiogenesis in hepatocellular carcinoma cell lines

Dramatic Response to Cabozantinib in a Patient with Refractory Hepatocellular Carcinoma with c-MET Amplification

We report a case of a patient with c-MET amplified hepatocellular carcinoma (HCC) who had a dramatic response to cabozantinib despite being refractory to four previous lines of systemic therapy. The patient had previously received regorafenib plus nivolumab as first-line treatment, lenvatinib as second-line, sorafenib as third-line, and ipilimumab plus nivolumab as fourth-line treatment in sequence. However, all regimens showed early progression within 2 months. The patient's HCC was well-controlled, with a partial response (PR) of over 9 months after beginning cabozantinib treatment. Although there were mild adverse events such as diarrhea and elevated liver enzymes, they were tolerable. Next-generation sequencing (NGS) of the patient's previous surgical specimen indicated amplification of c-MET genes. Although it is well known that cabozantinib has excellent effectiveness for inhibiting c-MET at the preclinical level, to the best of our knowledge this is the first case of dramatic response to cabozantinib in a patient with advanced HCC with c-MET amplification.

Acquisition of paclitaxel resistance modulates the biological traits of gastric cancer AGS cells and facilitates epithelial to mesenchymal transition and angiogenesis

PURPOSE

This study aims to develop a paclitaxel (PTX)-resistant gastric cancer AGS cells (AGS-R) and evaluate the mechanisms of drug resistance.

METHODS

AGS cells were successively treated with increasing PTX concentrations. Cross-resistance of established AGS-R, the molecular patterns of cell survival, evasion of apoptosis, epithelial-mesenchymal transition (EMT), and the angiogenic potential were evaluated.

RESULTS

AGS-R was induced within six months of PTX exposure. Extension of the treatment resulted in PTX-resistance beyond clinical levels. The established AGS-R showed resistance to vincristine and doxorubicin but not cisplatin. Upon induction of resistance, the expressions of MDR-1 (P < 0.001) and MRP-1 (P < 0.01) genes and proteins significantly increased. AGS-R cells had elevated levels of BCL-2, pro-CASP3, cleaved-NOTCH1, HES1, HEY1, NF-κB, PI3K, p-AKT, HIF-1α, Cyclin A, and B1 as compared with parental cells (at least P < 0.01). The protein levels of BAX, CASP3, P53, and P21 (at least P < 0.01) as well as intracellular ROS (P < 0.001) were reduced in AGS-R. A relative arrest at the G2/M phase (15.8 ± 0.75 vs. 26.7 ± 1.67) of the cell cycle and enrichment of AGS-R cells for CD44 marker (9 ± 0.6 vs. 1 ± 0.8) (P < 0.001) were detected by flow cytometry. While the E-cadherin expression was reduced (P < 0.001), the protein levels of Vimentin, N-cadherin, SLUG, and SNAIL were increased (at least P < 0.05). The angiogenic activity and release of VEGF and MMP2/9 were increased in AGS-R cells relative to the AGS line (P < 0.001).

CONCLUSION

AGS-R cells could bypass chemotherapy stress by expressing the genes coding for efflux pumps and altering some key signaling in favor of survival, EMT, and angiogenesis.

Mesenchymal Epithelial Transition Factor (MET): A Key Player in Chemotherapy Resistance and an Emerging Target for Potentiating Cancer Immunotherapy

The MET protein is a cell surface receptor tyrosine kinase predominately expressed in epithelial cells. Upon binding of its only known ligand, hepatocyte growth factor (HGF), MET homodimerizes, phosphorylates, and stimulates intracellular signalling to drive cell proliferation. Amplification or hyperactivation of MET is frequently observed in various cancer types and it is associated with poor response to conventional and targeted chemotherapy. More recently, emerging evidence also suggests that MET/HGF signalling may play an immunosuppressive role and it could confer resistance to cancer immunotherapy. In this review, we summarized the preclinical and clinical evidence of MET's role in drug resistance to conventional chemotherapy, targeted therapy, and immunotherapy. Previous clinical trials investigating MET-targeted therapy in unselected or MET-overexpressing cancers yielded mostly unfavourable results. More recent clinical studies focusing on MET exon 14 alterations and MET amplification have produced encouraging treatment responses to MET inhibitor therapy. The translational relevance of MET inhibitor therapy to overcome drug resistance in cancer patients is discussed.

The role of extracellular matrix in tumour angiogenesis: the throne has NOx servants

The extracellular matrix (ECM) dynamics in tumour tissue are deregulated compared to the ECM in healthy tissue along with disorganized architecture and irregular behaviour of the residing cells. Nitric oxide (NO) as a pleiotropic molecule exerts different effects on the components of the ECM driving or inhibiting augmented angiogenesis and tumour progression and tumour cell proliferation and metastasis. These effects rely on the concentration of NO within the tumour tissue, the nature of the surrounding microenvironment and the sensitivity of resident cells to NO. In this review article, we summarize the recent findings on the correlation between the levels of NO and the ECM components towards the modulation of tumour angiogenesis in different types of cancers. These are discussed principally in the context of how NO modulates the expression of ECM proteins resulting in either the promotion or inhibition of tumour growth via tumour angiogenesis. Furthermore, the regulatory effects of individual ECM components on the expression of the NO synthase enzymes and NO production were reviewed. These findings support the current efforts for developing effective therapeutics for cancers.

Studying Angiogenesis in the Rabbit Corneal Pocket Assay

The rabbit corneal micropocket assay uses the avascular cornea as a substrate to study angiogenesis in vivo. The continuous monitoring of neovascular growth in the same animal allows for the evaluation of drugs acting as suppressors or stimulators of angiogenesis. Through the use of standardized slow-release pellets, a predictable angiogenic response can be quantified over the course of 1-2 weeks. Uniform slow-release pellets are prepared by mixing purified angiogenic growth factors such as basic fibroblast growth factor (FGF) or vascular endothelial growth factor (VEGF) and a synthetic polymer to allow for their slow release. A micropocket is surgically created in the cornea thickness under anesthesia and in sterile conditions. The angiogenesis stimulus (growth factor but also tissue fragment or cell suspension) is placed into the pocket in order to induce vascular outgrowth from the limbal capillaries where vessels are preexisting. On the following days, the neovascular development and progression are measured and qualified using a slit lamp, as well as the concomitant vascular phenotype or inflammatory features. The results of the assay allow to assess the ability of potential therapeutic molecules to modulate angiogenesis in vivo, both when released locally or given by ocular formulations or through systemic treatment. In this chapter the experimental details of the avascular rabbit cornea assay, the technical challenges, advantages, and limitations are discussed.

The role of MET in chemotherapy resistance

Chemotherapy remains the mainstay of treatment in the majority of solid and haematological malignancies. Resistance to cytotoxic chemotherapy is a major clinical problem and substantial research is ongoing into potential methods of overcoming this resistance. One major target, the receptor tyrosine kinase MET, has generated increasing interest with multiple clinical trials in progress. Overexpression of MET is frequently observed in a range of different cancers and is associated with poor prognosis. Studies have shown that MET promotes resistance to targeted therapies, including those targeting EGFR, BRAF and MEK. More recently, several reports suggest that MET also contributes to cytotoxic chemotherapy resistance. Here we review the preclinical evidence of MET's role in chemotherapy resistance, the mechanisms by which this resistance is mediated and the translational relevance of MET inhibitor therapy for patients with chemotherapy resistant disease.

Epigallocatechin-3-gallate sensitises multidrug-resistant oral carcinoma xenografts to vincristine sulfate

Oral squamous cell carcinoma (OSCC) is a very aggressive malignancy, and 50% of patients who receive curative treatment die from the disease or related complications within 5 years. Epigallocatechin‐3‐gallate (EGCG) is the most abundant bioactive ingredient of tea polyphenols in green tea and has anticancer properties. Here, we evaluated the preclinical efficacy of EGCG combined with vincristine sulfate (VCR) on the growth, angiogenic activity and vascular endothelial growth factor (VEGF) expression in xenograft nude mice inoculated with KBV200 cells. Compared with VCR alone, the combined use of EGCG and VCR strongly inhibited tumour growth and angiogenesis (P < 0.01). VEGF mRNA and protein levels were lower in the KBV200 xenograft group treated with the combined regime (P < 0.01) than those in the VCR alone group. EGCG sensitises multidrug‐resistant OSCC to VCR, and this may occur through the inhibition of angiogenesis via VEGF down‐regulation.

High expression of FOXO3 is associated with poor prognosis in patients with hepatocellular carcinoma

The role of forkhead box O3 (FOXO3) as a tumor suppressor gene and its association with the human lifespan is well documented. However, several studies have indicated that high expression of FOXO3 is also significantly associated with tumorigenesis. The aim of the present study was to determine the clinical significance of FOXO3 in the development and prognosis of hepatocellular carcinoma (HCC). mRNA expression data of FOXO3 from The Cancer Genome Atlas database was analyzed through the UALCAN online tool to compare the expression of FOXO3 between HCC and normal liver tissues. Subsequently, the expression of FOXO3 at the protein level was investigated via immunohistochemical staining of 314 HCC and 150 non-cancerous liver tissue samples. The association between protein expression and clinicopathological parameters was analyzed using the χ² test, and the effect of FOXO3 expression on survival was assessed via Kaplan-Meier analysis. The expression of FOXO3 mRNA was significantly higher in HCC in comparison with healthy tissues. High FOXO3 protein expression was revealed in 43/150 non-cancerous liver tissues, and in 238/314 HCC samples. A significant association was demonstrated between FOXO3 expression and metastasis, Tumor-Node-Metastasis stage, Edmondson grade, α-fetoprotein level and overall survival. In conclusion, the high expression of FOXO3 predicts a poor prognosis in patients with HCC, indicating this protein as a potential therapeutic target in HCC.

NO and hepatocellular cancer

NO has broad and sometimes dichotomous roles in cancer. The effects of NO in tumours depend on the type and localization of NOS isoforms, concentration and duration of NO exposure, and cellular sensitivity to NO. Hepatocellular carcinoma (HCC) is a common and lethal disease for which no effective therapy other than surgical resection exists. Over two decades of research has yielded evidence that NO generated by the inducible NOS (iNOS or NOS2) contributes to HCC progression in at least a subset of patients with HCC. The co-expression of iNOS with COX-2 may portend a particularly aggressive cancer phenotype in HCC and at the same time reveal an opportunity for pharmacological intervention. In this review, we focus on what is known about the influence of NO in HCC neoplastic transformation, proliferation and apoptosis, angiogenesis, invasion, and metastasis, cancer stem cells, and the host immune response against the tumour. We discuss the implications of recent findings for targeting the NO pathways in HCC.

A meta-analysis of MDR1 polymorphisms rs1128503 and rs1045642 and susceptibility to hepatocellular carcinoma

Objective

A relationship between polymorphisms rs1128503 and rs1045642 in the multidrug resistance 1 gene ( MDR1) and susceptibility to hepatocellular carcinoma (HCC) has been reported but is inconclusive. This study was performed to explore the significance of MDR1 polymorphisms rs1128503 and rs1045642 in screening and diagnosis of HCC.

Methods

Studies of association analyses between MDR1 gene polymorphisms rs1128503 and rs1045642 and HCC were selected from three foreign language databases (PubMed, Cochrane, and Embase) and three Chinese databases (Wanfang, China National Knowledge Infrastructure, and China Knowledge Network) and subjected to meta-analysis.

Results

We found no significant relationship between the rs1128503 polymorphism and susceptibility to HCC in 4 cohorts and no significant relationship between the rs1045642 polymorphism and susceptibility to HCC in 3 cohorts.

Conclusions

There was no relationship between polymorphisms rs1128503 or rs1045642 of the MDR1 gene and susceptibility to HCC.

Targeting MRP4 expression by anti-androgen treatment reverses MRP4-mediated docetaxel resistance in castration-resistant prostate cancer

It has been demonstrated that docetaxel (DTX) may improve the overall survival of patients with castration-resistant prostate cancer (CRPC). However, its effectiveness is limited with time, and tumor escape is eventually inevitable. DTX resistance is the main reason for the failure of chemotherapy for CRPC. In the present study, the expression status of multidrug resistance protein 4 (MRP4) in DTX-resistant prostate cancer cells was investigated, and it was explored whether anti-androgen treatment may inhibit MRP4 expression and overcome DTX resistance. DTX-resistant C4-2/D cells were established by exposing DTX-sensitive C4-2/S cells to gradually increasing concentrations of DTX. MRP4 gene expression and the effect of androgen signaling on its expression were assessed by reverse transcription-polymerase chain reaction and western blotting. Intracellular and extracellular concentrations of DTX were detected by high-performance liquid chromatography. Anti-androgen treatment effects on DTX sensitivity were determined by a clonogenic test and an MTT cytotoxicity assay. MRP4 was overexpressed in C4-2/D cells, while its expression was barely detectable in C4-2/S cells. MRP4 expression levels were elevated in C4-2/D cells by dihydrotestosterone, whereas they were blocked by anti-androgen bicalutamide (BKL) treatment. Intracellular and extracellular DTX concentrations in C4-2/D cells were associated with MRP4 levels. The downregulation of MRP4 by BKL increased the intracellular concentration of DTX in C4-2/D cells and re-sensitized C4-2/D cells to DTX. These results indicated that overexpression of MRP4 mediates acquired DTX resistance, and suggest that targeting MRP4 expression by anti-androgen treatment may reverse DTX-resistant prostate cancer cells to DTX chemotherapy.

Clinical significance of expression of histone deacetylase 3 in hepatocellular carcinoma

AIM

To detect the expression of histone deacetylase 3 (HDAC3) in hepatocellular carcinoma (HCC) and analyze its clinicopathological significance.

METHODS

Immunohistochemistry was performed in 60 pairs of HCC tissues and tumor-adjacent normal tissues. The relationship of HDAC3 expression with clinical and pathological features and overall survival was analyzed statistically.

RESULTS

HDAC3 expression was significantly up-regulated in the HCC specimens compared to corresponding normal tissues (P < 0.05). The expression of HDAC3 in HCC had no significant correlation with gender, age, history of hepatitis B virus infection, TNM stage, pathological classification, α-fetoprotein level, liver cirrhosis, tumor size, or tumor number (P > 0.05). There was a positive correlation between HDAC3 and p-STAT3 expression in HCC tissues (r² = 0.622, P < 0.001). However, HDAC3 expression had a significant correlation with tumor recurrence (P < 0.05). The overall survival of postoperative HCC patients in the HDAC3 positive group was obviously poorer than that of patients in the HDAC3 negative group (P < 0.05), suggesting that high HDAC3 expression is associated with a poor prognosis in HCC patients.

CONCLUSION

The up-regulated expression of HDAC3 may be closely related with the occurrence and development of HCC.

Hepatocellular carcinoma: Where are we?

Hepatocellular carcinoma (HCC) is the second cause of death due to malignancy in the world, following lung cancer. The geographic distribution of this disease accompanies its principal risk factors: Chronic hepatitis B virus and hepatitis C virus infection, alcoholism, aflatoxin B1 intoxication, liver cirrhosis, and some genetic attributes. Recently, type II diabetes has been shown to be a risk factor for HCC together with obesity and metabolic syndrome. Although the risk factors are quite well known and it is possible to diagnose HCC when the tumor is less than 1 cm diameter, it remains elusive at the beginning and treatment is often unsuccessful. Liver transplantation is thus far considered the best treatment for HCC as it cures HCC and the underlying liver disease. Using the Milan criteria, overall survival after liver transplantation for HCC is about 70% after 5 years. Many attempts have been made to go beyond the Milan Criteria and according to recent works reasonably good results have been achieved by using a histochemical marker such as cytokeratine 19 and the so-called "up to seven criteria" to divide patients into categories according to their risk of relapse. In addition to liver transplantation other therapies have been proposed such as resection, tumor ablation by different means, embolization and chemotherapy. An important step in the treatment of advanced HCC has been the introduction of sorafenib, the first oral, systemic drug that has provided significant improvement in survival. Treatment of HCC patients must be multidisciplinary and by using the different approaches discussed in this review it is possible to offer prolonged survival and quite good and sometimes even excellent quality of life to many patients.

The Rabbit Corneal Pocket Assay

The rabbit corneal micropocket angiogenesis assay uses the avascular cornea as a substrate canvas to study angiogenesis in vivo. Through the use of standardized slow-release pellets, a predictable angiogenic response is generated over the course of 1-2 weeks and then quantified. Uniform slow-release pellets are prepared by mixing purified angiogenic growth factors such as basic fibroblast growth factor or vascular endothelial growth factor and a synthetic polymer to allow slow release. A micropocket is surgically created in the rabbit cornea under anesthesia and a pellet implanted. On the days later, the angiogenic response is measured and qualified using a slit lamp, as well as the concomitant vascular phenotype or inflammatory features. The results of the assay are used to assess the ability of potential therapeutic molecules to modulate angiogenesis in vivo, both when released locally or given by ocular formulations or through systemic treatment. In this chapter, the experimental details of the rabbit cornea assay and technical implementations to the original protocol are described.

Knockdown of c-MET induced apoptosis in ABCB1-overexpressed multidrug-resistance cancer cell lines

Inappropriate c-MET signaling in cancer can enhance tumor cell proliferation, survival, motility, and invasion. Inhibition of c-MET signaling induces apoptosis in a variety of cancers. It has also been recognized as a novel anticancer therapy approach. Furthermore, reports have also indicated that constitutive expression of P-glycoprotein (ABCB1) is involved in the HGF/c-MET-related pathway of multidrug resistance ABCB1-positive human hepatocellular carcinoma cell lines. We previously reported that elevated expression levels of PKCδ and AP-1 downstream genes, and HGF receptor (c-MET) and ABCB1, in the drug-resistant MES-SA/Dx5 cells. Moreover, leukemia cell lines overexpressing ABCB1 have also been shown to be more resistant to the tyrosine kinase inhibitor imatinib mesylate. These findings suggest that chemoresistant cancer cells may also develop a similar mechanism against chemotherapy agents. To circumvent clinical complications arising from drug resistance during cancer therapy, the present study was designed to investigate apoptosis induction in ABCB1-overexpressed cancer cells using c-MET-targeted RNA interference technology in vitro and in vivo. The results showed that cell viability decreased and apoptosis rate increased in c-MET shRNA-transfected HGF/c-MET pathway-positive MES-SA/Dx5 and MCF-7/ADR2 cell lines in a dose-dependent manner. In vivo reduction of tumor volume in mice harboring c-MET shRNA-knockdown MES-SA/Dx5 cells was clearly demonstrated. Our study demonstrated that downregulation of c-MET by shRNA-induced apoptosis in a multidrug resistance cell line.

HDAC3 acts as a negative regulator of angiogenesis

Histone deacetylase-3 (HDAC3) is involved in cellular proliferation, apoptosis and transcriptional repression. However, the role of HDAC3 in angiogenesis remains unknown. HDAC3 negatively regulated the expression of angiogenic factors, such as VEGF and plasminogen activator inhibitor-1 (PAI-1). HDAC3 showed binding to promoter sequences of PAI-1. HDAC3 activity was necessary for the expression regulation of PAI-1 by HDAC3. VEGF decreased the expression of HDAC3, and the down-regulation of HDAC3 enhanced endothelial cell tube formation. HDAC3 negatively regulated tumor-induced angiogenic potential. We show the novel role of HDAC3 as a negative regulator of angiogenesis. [BMB Reports 2014; 47(4): 227-232]

Mitochondria of a human multidrug-resistant hepatocellular carcinoma cell line constitutively express inducible nitric oxide synthase in the inner membrane

Mitochondria play a crucial role in pathways of stress conditions. They can be transported from one cell to another, bringing their features to the cell where they are transported. It has been shown in cancer cells overexpressing multidrug resistance (MDR) that mitochondria express proteins involved in drug resistance such as P-glycoprotein (P-gp), breast cancer resistant protein and multiple resistance protein-1. The MDR phenotype is associated with the constitutive expression of COX-2 and iNOS, whereas celecoxib, a specific inhibitor of COX-2 activity, reverses drug resistance of MDR cells by releasing cytochrome c from mitochondria. It is possible that COX-2 and iNOS are also expressed in mitochondria of cancer cells overexpressing the MDR phenotype. This study involved experiments using the human HCC PLC/PRF/5 cell line with and without MDR phenotype and melanoma A375 cells that do not express the MDR1 phenotype but they do iNOS. Western blot analysis, confocal immunofluorescence and immune electron microscopy showed that iNOS is localized in mitochondria of MDR1-positive cells, whereas COX-2 is not. Low and moderate concentrations of celecoxib modulate the expression of iNOS and P-gp in mitochondria of MDR cancer cells independently from inhibition of COX-2 activity. However, A375 cells that express iNOS also in mitochondria, were not MDR1 positive. In conclusion, iNOS can be localized in mitochondria of HCC cells overexpressing MDR1 phenotype, however this phenomenon appears independent from the MDR1 phenotype occurrence. The presence of iNOS in mitochondria of human HCC cells phenotype probably concurs to a more aggressive behaviour of cancer cells.

The corneal pocket assay

The cornea in most species is physiologically avascular, and thus this assay allows the measurement of newly formed vessels. The continuous monitoring of neovascular growth in the same animal allows the evaluation of drugs acting as suppressors or stimulators of angiogenesis. Under anesthesia a micropocket is produced in the cornea thickness and the angiogenesis stimulus (tumor tissue, cell suspension, growth factor) is placed into the pocket in order to induce vascular outgrowth from the limbal capillaries. Neovascular development and progression can be modified by the presence of locally released or applied inhibitory factors or by systemic treatments. In this chapter the experimental details of the avascular cornea assay, the technical challenges, and advantages and disadvantages in different species are discussed. Protocols for local drug treatment and tissue sampling for histology and pharmacokinetic profile are reported.

Delivery of doxorubicin across the blood-brain barrier by ondansetron pretreatment: a study in vitro and in vivo

Doxorubicin (Dox) has got a limited efficacy in the treatment of central nervous system tumors because of its poor penetration through blood-brain barrier mediated by MDR efflux transporters. We investigated the possibility that ondansetron (Ond) enhances Dox cytotoxicity in cell lines interfering with P-glycoprotein and increases Dox concentration in rat brain tissues. The MDR phenotype was studied using human hepatocellular carcinoma cell line PLC/PRF/5 (P5 and P1(0.5) clones), two subclones of NIH 3T3 cells (PSI-2 and PN1A) and two glioblastoma cell lines (A172, U87MG). Rats were pretreated with Ond before injection of Dox. Quantitative analysis of Dox was performed by mass spectrometry. Our in vitro experiments demonstrated that Ond at 10 µg/ml is not toxic to all cell lines. However, Ond reverses the MDR phenotype in P1(0.5) and PN1A cell lines. In addition, we showed that pretreatment with Ond increases Dox concentration in rat brain tissues, without increasing acute heart and renal toxicity.

c-Met: A potential therapeutic target for hepatocellular carcinoma

The approval of receptor tyrosine kinase (RTK) targeted agent sorafenib as the first effective drug for the systemic treatment of advanced hepatocellular carcinoma (HCC) represents a milestone in the treatment of this disease. A better understanding of HCC pathogenesis will lead to development of novel targeted treatments. As a typical member of the RTK family, c-Met represents an intriguing target for cancer therapy. The c-Met signaling pathway has been shown to be deregulated and to correlate with poor prognosis in a number of major human cancers. This review discusses the possibility of c-Met as a target in HCC treatment from the following respects: i) c-Met expression and activation profile in HCC, ii) relationship between c-Met and clinicopathologic state and prognosis of HCC, iii) role of c-Met signaling activity in HCC genesis and progression, and iv) strategy of c-Met pathway targeting therapy in HCC treatment.

Future directions in the evaluation of c-MET-driven malignancies

The c-MET (mesenchymal-epithelial transition factor) receptor tyrosine kinase is an exciting novel drug target in view of its key role in oncogenesis, as well as its association with disease prognosis in a number of malignancies. Several drugs targeting c-MET are currently showing promise in clinical trials and will hopefully validate positive observations from preclinical studies. The potential efficacy of these different therapeutic agents is expected to be influenced by the mechanism of aberrant hepatocyte growth factor (HGF)/c-MET signaling pathway activation in a particular cancer, but presents a promising strategy for cancer treatment either as a single agent or as part of a combination therapeutic approach. However, there is an ongoing need to improve and accelerate the transition of preclinical research into improved therapeutic strategies for patients with cancer. The main challenges facing the development of HGF/c-MET-targeted agents for cancer treatment include the discovery of rationally designed anticancer drugs and combination strategies, as well as the validation of predictive biomarkers. This paper discusses these issues, with a particular focus on future directions in the evaluation of c-MET-driven malignancies.

A hepatoprotective Lindera obtusiloba extract suppresses growth and attenuates insulin like growth factor-1 receptor signaling and NF-kappaB activity in human liver cancer cell lines

Background

In traditional Chinese and Korean medicine, an aqueous extract derived from wood and bark of the Japanese spice bush Lindera obtusiloba (L.obtusiloba) is applied to treat inflammations and chronic liver diseases including hepatocellular carcinoma. We previously demonstrated anti-fibrotic effects of L.obtusiloba extract in hepatic stellate cells. Thus, we here consequently examine anti-neoplastic effects of L.obtusiloba extract on human hepatocellular carcinoma (HCC) cell lines and the signaling pathways involved.

Methods

Four human HCC cell lines representing diverse stages of differentiation were treated with L.obtusiloba extract, standardized according to its known suppressive effects on proliferation and TGF-β-expression. Beside measurement of proliferation, invasion and apoptosis, effects on signal transduction and NF-κB-activity were determined.

Results

L.obtusiloba extract inhibited proliferation and induced apoptosis in all HCC cell lines and provoked a reduced basal and IGF-1-induced activation of the IGF-1R signaling cascade and a reduced transcriptional NF-κB-activity, particularly in the poorly differentiated SK-Hep1 cells. Pointing to anti-angiogenic effects, L.obtusiloba extract attenuated the basal and IGF-1-induced expression of hypoxia inducible factor-1α, vascular endothelial growth factor, peroxisome proliferator-activated receptor-γ, cyclooxygenase-2 and inducible nitric oxide synthase.

Conclusions

The traditional application of the extract is confirmed by our experimental data. Due to its potential to inhibit critical receptor tyrosine kinases involved in HCC progression via the IGF-1 signaling pathway and NF-κB, the standardized L.obtusiloba extract should be further analysed for its active compounds and explored as (complementary) treatment option for HCC.

Establishment of a human hepatoma multidrug resistant cell line in vitro

AIM: To establish a multidrug-resistant hepatoma cell line (SK-Hep-1), and to investigate its biological characteristics.

METHODS: A highly invasive SK-Hep-1 cell line of human hepatocellular carcinoma, also known as malignant hepatoma was incubated with a high concentration of cisplatin (CDDP) to establish a CDDP-resistant cell subline (SK-Hep-1/CDDP). The 50% inhibitory dose (IC₅₀) values and the resistance indexes [(IC₅₀ SK-Hep-1/CDDP)/(IC₅₀ SK-Hep-1)] for other chemotherapeutic agents and the growth curve of cells were all evaluated using cell counting kit-8 assays. The distribution of the cell cycles were detected by flow cytometry. Expression of acquired multidrug resistance P-glycoprotein (MDR1, ABCB1) and multidrug resistance-associated protein 1 (MRP1, ABCC1) was compared with that in parent cells by Western blotting and immunofluorescence combined with laser scanning confocal microscopy.

RESULTS: The SK-Hep-1/CDDP cells (IC₅₀ = 70.61 ± 1.06 μg/mL) was 13.76 times more resistant to CDDP than the SK-Hep-1 cells (IC₅₀ = 5.13 ± 0.09 μg/mL), and CDDP-resistant cells also demonstrated cross-resistance to many anti-tumor agents such as doxorubicin, 5-fluorouracil and vincristine. Similar morphologies were determined in both SK-Hep-1 and SK-Hep-1/CDDP groups. The cell cycle distribution of the SK-Hep-1/CDDP cell line exhibited a significantly increased percentage of cells in S (42.2% ± 2.65% vs 27.91% ± 2.16%, P < 0.01) and G2/M (20.67% ± 5.69% vs 12.14% ± 3.36%, P < 0.01) phases in comparison with SK-Hep-1 cells, while the percentage of cells in the G0/G1 phase decreased (37.5% ± 5.05% vs 59.83% ± 3.28%, P < 0.01). The levels of MDR1 and MRP1 were overexpressed in the SK-Hep-1/CDDP cells exhibiting the MDR phenotype.

CONCLUSION: Multiple drug resistance of multiple drugs in the human hepatoma cell line SK-Hep-1/CDDP was closely related to the overexpression of MDR1 and MRP1.

Alterations of cellular organelles in human liver-derived hepatoma G2 cells induced by adriamycin

Adriamycin (ADM) is a commonly used chemotherapeutic drug in the treatment of hepatocellular carcinoma. However, the mechanisms involved in ADM-induced cell death and the molecular basis of ADM resistance are still unclear. To observe the early events that occurred in hepatoma cells in response to ADM, we investigated the alterations of morphology and subcellular distributions of cellular organelles in human liver-derived hepatoma G2 (HepG2) cells after ADM treatment. HepG2 cells were exposed to different doses of ADM for up to 60 h. Cytotoxicity occurred 24 h after 0.05 microg/ml ADM application, and remaining living cells showed irregular shapes but continued to multiply. Some cellular organelles altered their subcellular distribution or morphology after ADM treatment, including mitochondria, autophagic vacuoles, and Golgi apparatus. Immunoblotting with anti-LC3 antibody showed the upregulation of LC3-II protein, confirming that ADM leads to the induction of autophagy in HepG2 cells. Our findings suggest that among most of the cellular organelles, mitochondria and autophagic vacuoles were involved in the early ADM response, and may contribute to ADM-induced HepG2 cell death.

Expression of hepatocyte growth factor and basic fibroblast growth factor as prognostic indicators in gastric cancer

We have investigated the correlations among hepatocyte growth factor (HGF) mRNA expression, basic fibroblast growth factor (bFGF) mRNA expression, tumor microvessel density (MVD), and clinical pathological features of gastric cancer in Chinese patients. In situ hybridization was used to detect the expression of HGF and bFGF mRNAs, and immunohistochemistry was used to detect CD34 in 105 gastric cancer tissues and in 20 normal control tissues. The rate of HGF mRNA expression in normal gastric tissues (25%) was significantly lower than that (57.1%) in tumor tissues (P < 0.01). The rates of HGF mRNA and bFGF mRNA expression and MVD in T3-T4 stage tissues were higher than those in T1-T2 stage tissues (P < 0.01); the HGF mRNA expression rate was directly correlated with the bFGF mRNA expression rate (P < 0.05), and they were also directly correlated with MVD (P < 0.01). The mean survival time and the 5-year survival rate of patients who were positive for expression of HGF mRNA and bFGF mRNA and who had a MVD >or= 39.5/0.72 mm(2) were significantly shorter than those who did not express HGF mRNA and bFGF mRNA and who had a MVD <39.5/0.72 mm(2). Both HGF and bFGF may participate in angiogenesis in gastric cancer and may be involved in tumor invasion and metastasis. HGF and bFGF mRNA expression can be used as useful parameters to evaluate the prognosis of gastric cancer.

Down-regulation of the HGF/MET autocrine loop induced by celecoxib and mediated by P-gp in MDR-positive human hepatocellular carcinoma cell line

Many tumors are resistant to drug-induced cell-cycle arrest and apoptosis. We have reported that apoptosis can be restored in human multidrug-resistant (MDR) hepatocellular carcinoma cell lines by celecoxib. Here we show that P-glycoprotein (P-gp) mediates cell-cycle arrest and autophagy induced by celecoxib in human MDR overexpressing hepatocellular carcinoma cell line by down-regulation of the HGF/MET autocrine loop and Bcl-2 expression. Exposure of cells to a low concentration of celecoxib down-regulated the expression of mTOR and caused G1 arrest and autophagy, while higher concentration triggered apoptosis. Cell growth inhibition and autophagy were associated with up-regulation of the expression of TGFbeta1, p16(INK4b), p21(Cip1) and p27(Kip1) and down-regulation of cyclin D1, cyclin E, pRb and E2F. The role of P-glycoprotein expression in resistance of MDR cell clone to cell-cycle arrest, autophagy and apoptosis was shown in cells transfected with MDR1 small interfering RNA. These findings demonstrate that the constitutive expression of P-gp is involved in the HGF/MET autocrine loop that leads to increased expression of Bcl-2 and mTor, inhibition of eIF2alpha expression, resistance to autophagy/apoptosis and progression in the cell-cycle. Since mTor inhibitors have been proposed in treatment of "drug resistant" cancer, these data may help explain the reversing effect of mTor inhibitors.

Molecular targeted therapy for hepatocellular carcinoma

A majority of patients with HCC present with advanced disease and are not candidates for liver transplantation, surgical resection, or regional therapy. Systemic cytotoxic chemotherapy agents are minimally effective, can have significant toxicity, and have not been shown to improve patient survival. Hepatocellular carcinomas are inherently chemotherapy-resistant tumors and are known to overexpress the multidrug resistance genes. Hepatocellular carcinoma is a very heterogeneous disease in terms of its etiology, molecular carcinogenic mechanisms, and biological behavior, which complicate our ability to identify rational molecular therapeutic "targets." Nearly every pathway involved in carcinogenesis is altered to some degree in HCC. Changes in hepatocyte growth factor expression, intracellular signaling, protease and matrix metalloproteinase expression, and oncogene expression are seen in HCC. The recent demonstration, in randomized clinical trials, of survival benefit for HCC patients treated with the oral agent sorafenib is encouraging progress in the development of molecularly targeted anticancer agents in HCC.

The corneal pocket assay

Continuous monitoring of neovascular growth in vivo is required for the development and evaluation of drugs acting as suppressors or stimulators of angiogenesis. The cornea assay consists of the placement of an angiogenesis stimulus (tumor tissue, cell suspension, growth factor) into a micropocket produced in the cornea thickness to evoke vascular outgrowth from the peripherally located limbal vasculature. Neovascular development and progression can be modified by the presence of locally released or applied inhibitory factors or by systemically given antiangiogenic drugs. This assay has the advantage over other in vivo assays of measuring new blood vessels only since the cornea is initially avascular. The experimental details of the avascular cornea assay and its advantages and disadvantages in different species are discussed.

Single-agent and combination therapeutic strategies to inhibit hepatocyte growth factor/MET signaling in cancer

Receptor tyrosine kinases are often aberrantly activated in human malignancies and contribute to cancer development and progression. Specific receptor tyrosine kinase inhibitors have been shown to be clinically effective therapies in subsets of cancer patients with either hematologic or solid tumors. Activation of the hepatocyte growth factor (HGF)/MET signaling pathway has been found to play a critical role in oncogenesis, cancer metastasis, and drug resistance. These observations have led to the development of agents that can effectively inhibit HGF/MET signaling through direct inhibition of the receptor (anti-MET antibodies), through inactivation of its ligand HGF (AMG102, L2G7), by interfering with HGF binding to MET (NK4), or by inhibiting MET kinase activity (PHA-665752 and SU11274). Moreover, the combination of anti-MET therapeutic agents with either signal transduction inhibitors (ERBB family or mTOR inhibitors) or with cytotoxic chemotherapy has been evaluated in preclinical models. These studies provide insight into the rational development of combination therapeutic strategies that can be evaluated in clinical trials. This review will discuss different strategies of MET inhibition with a specific focus on combination therapeutic approaches.

Interaction of major genes predisposing to hepatocellular carcinoma with genes encoding signal transduction pathways influences tumor phenotype and prognosis

Studies on rodents and humans demonstrate an inherited predisposition to hepatocellular carcinoma (HCC). Analysis of the molecular alterations involved in the acquisition of a phenotype resistant or susceptible to hepatocarcinogenesis showed a deregulation of G1 and S phases in HCC of genetically susceptible F344 rats and a G1-S block in lesions of resistant Brown norway (BN) rats. Unrestrained extracellular signal-regulated kinase (ERK) activity linked to proteasomal degradation of dual-specificity phosphatase 1 (DUSP1), a specific ERK inhibitor, by the CKS1-SKP2 ubiquitin ligase complex occurs in more aggressive HCC of F344 rats and humans. This mechanism is less active in HCC of BN rats and human HCC with better prognosis. Upregulation of iNos cross-talk with IKK/NF-κB and RAS/ERK pathways occurs in rodent liver lesions at higher levels in the most aggressive models represented by HCC of F344 rats and c-Myc-TGF-α transgenic mice. iNOS, IKK/NF-κB, and RAS/ERK upregulation is highest in human HCC with a poorer prognosis and positively correlates with tumor proliferation, genomic instability and microvascularization, and negatively with apoptosis. Thus, cell cycle regulation and the activity of signal transduction pathways seem to be modulated by HCC modifier genes, and differences in their efficiency influence the susceptibility to hepatocarcinogenesis and probably the prognosis of human HCC.

Systemic therapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is currently the fifth most common solid tumor worldwide and the third leading cause of cancer-related death. Eighty percent of new cases occur in developing countries, but the incidence is rising in economically developed regions including Japan, Western Europe, and the United States. More than 80% of patients present with advanced or unresectable disease, and for those patients who do undergo resection, the recurrence rates can be as high as 50% at 2 years. Thus, a large number of patients will seek systemic therapy. Systemic cytotoxic chemotherapy is largely ineffective and can have significant toxicity in patients with underlying liver dysfunction. Newer biologic agents that target molecular abnormalities common to HCC may improve the clinical outcome in patients with HCC.

Systemic therapy for hepatocellular carcinoma: cytotoxic chemotherapy, targeted therapy and immunotherapy

Conventional cytotoxic chemotherapy has not provided clinical benefit or prolonged survival for patients with advanced HCC. This review summarizes the results of prospective clinical trials of several categories of systemic therapy, with emphasis on the more promising results from recent trials of biologically targeted therapeutic agents in HCC.

Hepatocellular carcinoma: epidemiology and clinical aspects

Liver cancer is one of the most frequent solid cancers that kills more than 650,000 people around the world each year. Though great improvements have been done in last 10 years on the understanding the molecular mechanisms involved in liver oncogenesis, the prognosis of patients affected by liver cancer is still poor for most of them. Even in those where a relatively early diagnosis is done, the course of the disease is often fatal due to the underlying liver cirrhosis. In this review authors report the most recent findings on the pathogenesis of liver cancer and on therapeutic approaches, included those emerging from the most recent literature.

Corticotropin-releasing factor family and its receptors: tumor therapeutic targets?

Urocortin (UCN) and corticotropin-releasing factor (CRF) are members of CRF family. Though CRF is mainly distributed in central nervous system (CNS), UCN has been reported to play biologically diverse roles in several systems such as cardiovascular, respiratory, digestive, reproductive, stress, immunologic system, etc. UCN and CRF bind to two known receptors, CRFR1 and CRFR2, to function. Both CRF receptors are distributed in CNS and periphery tissues, and their expression in cancer tissues has been reported. Now there are many documents indicating UCN/CRF play an important role in the regulation of carcinogenesis. There is also evidence indicating UCN/CRF have anticancer effects via CRFRs. This paper will review the effects of CRF family in cancers.

Chemotherapeutic stress selectively activates NF-κB-dependent AKT and VEGF expression in liver cancer-derived endothelial cells

Targeting endothelial cells (EC) that line tumor blood vessels forms the basis for metronomic therapy and is a promising new strategy for the treatment of cancer. Genetic and phenotypic differences between tumor-derived and normal ECs indicate that targeting tumor ECs may be therapeutically useful. In the present study, we examined differences in responses to chemotherapy in microvascular EC lines from tumoral (T-EC) and normal (N-EC) mouse liver tissues. The identity of these cells was confirmed by immunocytochemistry for EC markers, such as vascular endothelial-cadherin and CD31 for both types of ECs, and the tumor-endothelial-specific marker tumor endothelial marker-7 for T-EC. The involvement of Akt in NF-κB-dependent angiogenesis was different between N-EC and T-EC. Chemotherapeutic stress increased angiogenesis in T-EC, but not N-EC via an NF-κB-Akt-dependent manner. Both NF-κB and Akt were involved in enhanced survival and migration in T-EC in response to chemotherapeutic stress. Moreover, Akt was involved in NF-κB-dependent VEGF expression and angiogenesis. These studies, showing differences in cellular responses to chemotherapy in tumor-derived ECs, indicate that specific therapies targeting these cells may be therapeutically useful for liver cancers.

P-glycoprotein mediates celecoxib-induced apoptosis in multiple drug-resistant cell lines

In several neoplastic diseases, including hepatocellular carcinoma, the expression of P-glycoprotein and cyclooxygenase-2 (COX-2) are often increased and involved in drug resistance and poor prognosis. P-glycoprotein, in addition to drug resistance, blocks cytochrome c release, preventing apoptosis in tumor cells. Because COX-2 induces P-glycoprotein expression, we evaluated the effect of celecoxib, a specific inhibitor of COX-2 activity, on P-glycoprotein-mediated resistance to apoptosis in cell lines expressing multidrug resistant (MDR) phenotype. Experiments were done using MDR-positive and parental cell lines at basal conditions and after exposure to 10 or 50 micromol/L celecoxib. We found that 10 micromol/L celecoxib reduced P-glycoprotein, Bcl-x(L), and Bcl-2 expression, and induced translocation of Bax from cytosol to mitochondria and cytochrome c release into cytosol in MDR-positive hepatocellular carcinoma cells. This causes the activation of caspase-3 and increases the number of cells going into apoptosis. No effect was shown on parental drug-sensitive or on MDR-positive hepatocellular carcinoma cells after transfection with MDR1 small interfering RNA. Interestingly, although inhibiting COX-2 activity, 50 micromol/L celecoxib weakly increased the expression of COX-2 and P-glycoprotein and did not alter Bcl-x(L) and Bcl-2 expression. In conclusion, these results show that relatively low concentrations of celecoxib induce cell apoptosis in MDR cell lines. This effect is mediated by P-glycoprotein and suggests that the efficacy of celecoxib in the treatment of different types of cancer may depend on celecoxib concentration and P-glycoprotein expression.

Cell death signal by glycine- and proline-rich plant glycoprotein is transferred from cytochrome c and nuclear factor kappa B to caspase 3 in Hep3B cells

This study was carried out to investigate the apoptotic effects of glycine- and proline-rich glycoprotein [Solanum nigrum Linne (SNL) glycoprotein, 150-kDa] isolated from SNL, which has been used as an antipyretic and anticancer agent in Korean herbal medicine. We found that SNL glycoprotein has obviously cytotoxic and apoptotic effects at 80 microg/ml of SNL glycoprotein for 4 h in Hep3B cells (hepatocellular carcinoma cells). In mitochondria-mediated apoptosis pathway, SNL glycoprotein has abilities to stimulate release of mitochondrial cytochrome c, activations of caspase-9 and caspase-3, cleavage of poly(ADP-ribose)polymerase and production of intracellular reactive oxygen species in Hep3B cells. In nuclear factor-kappa B (NF-kappaB)-mediated apoptosis pathway, the results showed that SNL glycoprotein dose-dependently blocked DNA binding activity of NF-kappaB, activity of inducible nitric oxide synthase (iNOS) and production of inducible nitric oxide (NO). Interestingly, pyrrolidine dithiocarbamate (for NF-kappaB inhibitor) and Nomega-nitro-l-arginine methylester hydrochloride (for NO inhibitor) effectively stimulated the caspase-3 activation and induced apoptosis in Hep3B cells. These results indicate that SNL glycoprotein transfers its cell death signal from cytochrome c to caspase 3 by inhibiting NF-kappaB and iNOS activation in Hep3B cells. Here, we speculate that SNL glycoprotein is one of the chemotherapeutic agents to modulate mitochondria-mediated apoptosis signals in Hep3B cells.

Multifactorial nature of hepatocellular carcinoma drug resistance: could plant polyphenols be helpful?

Primary hepatocellular carcinoma (HCC) is a quite frequent tumor which results in high mortality and most often exhibits a poor response to present drug therapies. Clearly, a thorough understanding of the biological bases of this malignancy might suggest new strategies for its treatment. Here we examine the evidences that both "pharmacological" mechanisms (e.g. drug transporter or detoxification enzyme over-expression) and alterations in other critical factors, including the IAPs (Inhibitory of Apoptosis Proteins), involved in enhancement of cell survival and proliferation may determine the therapeutic resistance of HCC; we also underline the possible role in the process of the activation of transcription factors, like NF-kappaB, capable of contemporaneously up-regulating the mechanisms discussed. On this basis, we finally comment on the possible use of natural multi-targeted antitumoral agents like plant polyphenols to achieve sensitization to treatments in HCC.

MDR1 gene polymorphisms and risk of recurrence in patients With hepatocellular carcinoma after liver transplantation

BACKGROUND AND OBJECTIVES

Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) remains a major cause of post-LT death. However, currently there is still lacking the markers to reliably predict recurrence. This study was undertaken to evaluate the association between three polymorphisms (C1236T, G2677A/T, C3435T) of Multidrug resistance 1 (MDR1) gene and the risk of recurrence after LT.

METHODS

Genomic DNA of 99 HCC patients undergoing LT was extracted from peripheral blood lymphocytes and genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism assay. Cox proportional hazard model was used to estimate the hazard ratios associated with polymorphisms.

RESULTS

During a mean follow-up of 14.9 months, 49 patients experienced recurrence. The association between recurrence-free and 2677A carrier (carrying at least one variant A allele) was significant (P = 0.019). However, no significant association was observed in other polymorphisms. Patients with 2677A carrier conferred a 63% reduction in recurrence risk compared with 2677A non-carrier (odds ratio: 0.374; 95% confidence interval: 0.177-0.788; P = 0.010). The median recurrence-free survival for 2677A carrier group was significantly longer than that for 2677A non-carrier group (44.2 vs. 10.5 months, P = 0.015).

CONCLUSION

The polymorphism of MDR1 gene may be a valuable molecular marker for HCC recurrence after LT.

P-gp localization in mitochondria and its functional characterization in multiple drug-resistant cell lines

Multidrug resistance (MDR) phenotype is characterized by the over-expression of P-glycoprotein (P-gp) on cell plasma membranes that extrudes several drugs out of cells. Cells that express the MDR phenotype are resistant to the mitochondrial related apoptosis and to several anticancer drugs. This study assessed the presence of P-gp in mitochondria and its role in parental drug-sensitive (P5) and in P5-derived MDR1 cells P1(0.5) hepatocellular carcinoma (HCC) cell lines and in drug-sensitive (PSI-2) and mdr1-transfected (PN1A) NIH/3T3 cells. By using Western blot analysis, confocal laser microscopy, measurements of Rhodamine 123 transport across mitochondrial membranes, MDR1 small interfering RNA and flow cytometry analysis, experiments indicate that P-gp is expressed in mitochondria of P1(0.5) and PN1A cells and it is functionally active. Rho 123 accumulation was largely reduced in mitochondria of P1(0.5) cells as compared to those of P5 cells; the reduced uptake of fluorescence in mitochondria of MDR cells was due to P-gp-mediated Rho 123 efflux. In conclusion, these data demonstrate that functionally active P-gp is expressed in the mitochondrial membrane of MDR-positive cells and pumps out anticancer drugs from mitochondria into cytosol. Therefore, P-gp could be involved in the protection of mitochondrial DNA from damage due to antiproliferative drugs.

Androgen induces expression of the multidrug resistance protein gene MRP4 in prostate cancer cells

Multidrug resistance-associated proteins (MRPs) may mediate multidrug resistance in tumor cells. Using a gene array analysis, we have identified MRP4 as an androgen receptor (AR)-regulated gene. Dihydrotestosterone induced MRP4 expression in both androgen-dependent and -independent LNCaP cells, whereas there was little detectable expression in PC-3 or normal prostate epithelial cells. Disruption of MRP4 expression renders LNCaP cells more sensitive to the cytotoxic effects of methotrexate but not etoposide. Analysis of human tissues showed detectable MRP4 expression only in metastatic prostate cancer. These results suggest that AR induction of MRP4 mediates resistance of PC cells to nucleotide-based chemotherapeutic drugs.

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