Positron emission tomography diagnostic imaging in multidrug-resistant hepatocellular carcinoma: focus on 2-deoxy-2-(18F)Fluoro-D-Glucose

Wireless sequential dual light delivery for programmed PDT in vivo

Using photodynamic therapy (PDT) to treat deep-seated cancers is limited due to inefficient delivery of photosensitizers and low tissue penetration of light. Polymeric nanocarriers are widely used for photosensitizer delivery, while the self-quenching of the encapsulated photosensitizers would impair the PDT efficacy. Furthermore, the generated short-lived reactive oxygen spieces (ROS) can hardly diffuse out of nanocarriers, resulting in low PDT efficacy. Therefore, a smart nanocarrier system which can be degraded by light, followed by photosensitizer activation can potentially overcome these limitations and enhance the PDT efficacy. A light-sensitive polymer nanocarrier encapsulating photosensitizer (RB-M) was synthesized. An implantable wireless dual wavelength microLED device which delivers the two light wavelengths sequentially was developed to programmatically control the release and activation of the loaded photosensitizer. Two transmitter coils with matching resonant frequencies allow activation of the connected LEDs to emit different wavelengths independently. Optimal irradiation time, dose, and RB-M concentration were determined using an agent-based digital simulation method. In vitro and in vivo validation experiments in an orthotopic rat liver hepatocellular carcinoma disease model confirmed that the nanocarrier rupture and sequential low dose light irradiation strategy resulted in successful PDT at reduced photosensitizer and irradiation dose, which is a clinically significant event that enhances treatment safety.

An injectable thermosensitive hydrogel loading with theranostic nanoprobe for synergetic chemo-photothermal therapy of multidrug-resistant hepatocellular carcinoma

Multi-drug resistance (MDR) is a complicated cellular defense mechanism for tumor cells to resist chemotherapy drugs, which is also the main cause of chemotherapy failure. In this study, we used...

68Ga-PSMA PET/CT Versus 18F-FDG PET/CT for Imaging of Hepatocellular Carcinoma

Objectives:

This study aimed to compare the metabolic parameters obtained from ¹⁸fluorine-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 (⁶⁸Ga)-prostate-specific membrane antigen (PSMA) PET/CT and investigate the relationship between serum alpha-fetoprotein and PET scan parameters in patients with hepatocellular carcinoma.

Methods:

Fourteen patients were recruited after dynamic magnetic resonance imaging (MRI) of the upper abdomen, and ¹⁸F-FDG and ⁶⁸Ga-PSMA PET/CT imaging studies were conducted. Regions of interest (ROIs) were drawn from lesion-free liver tissue, abdominal aorta (A), and right medial gluteal muscle (G) for the background activity. Maximum standard uptake value (SUV_max) of these regions were compared with the SUV_max of primary tumor (T).

Results:

On visual assessment, five patients (36%) experienced low ¹⁸F-FDG uptake in the primary lesion, three patients (21%) experienced moderate uptake, and six patients (43%) experienced high uptake. However, only one patient (7%) showed low ⁶⁸Ga-PSMA uptake, two patients (14%) showed moderate uptake, and 11 patients (79%) showed high uptake. Four patients with a low ¹⁸F-FDG uptake showed high ⁶⁸Ga-PSMA uptake, while one patient exhibited low uptake with both ¹⁸F-FDG and ⁶⁸Ga-PSMA. The number of lesions on ⁶⁸Ga-PSMA PET/CT and MRI was significantly higher than ¹⁸F-FDG PET/CT (p=0.042 and 0.026, respectively). T/A and T/G values were significantly higher in ⁶⁸Ga-PSMA than ¹⁸F-FDG (p=0.002 and 0.002, respectively).

Conclusion:

⁶⁸Ga-PSMA PET/CT is superior to ¹⁸F-FDG PET/CT in the staging of hepatocellular carcinoma. High ⁶⁸Ga-PSMA uptake could be promising for PSMA-targeted radionuclide treatments.

A novel rabbit fixator made of a thermoplastic mask for awake imaging experiments

This study aimed to develop and validate a novel rabbit fixator made from a thermoplastic mask for awake imaging experiments. When heated in a hot-water bath at 65–70 °C for 2–5 min, the thermoplastic mask became soft and could be molded to fit over the entire body of an anesthetized rabbit (4 ml of 3% pentobarbital sodium solution by intramuscular injection). Twenty rabbits were randomly divided into fixator (n = 10) and anesthesia (n = 10) groups. The animals’ vital signs, stress hormones (cortisol and adrenaline), and subjective image quality scores for the computed tomography (CT), positron emission tomography (PET), and magnetic resonance imaging (MRI) scanning were measured and compared. Phantom CT, MRI and PET studies were performed to assess the performance with and without the thermoplastic mask by using image agents at different concentrations or with different radioactivity. The respiration rate (RR), systolic blood pressure (SBP), diastolic blood pressure (DBP), peripheral capillary oxygen saturation (SpO₂) and body temperature (T) decreased after anesthesia (all P < 0.05) but did not significantly decrease after fixation (all P > 0.05). The heart rate (HR), cortisol and adrenaline did not significantly decrease after either anesthesia or fixation (all P > 0.05). The subjective image quality scores for the CT and MRI images of the head, thorax, liver, kidney, intestines and pelvis and the subjective image quality scores for the PET images did not significantly differ between the two groups (all P > 0.05). For all examined organs except the muscle, ¹⁸F-FDG metabolism was lower after fixation than after anesthesia, and was almost identical of liver between two groups. The phantom study showed that the CT values, standard uptake values and MR T2 signal values did not differ significantly with or without the mask (all P > 0.05). A novel rabbit fixator created using a thermoplastic mask could be used to obtain high-quality images for different imaging modalities in an awake and near-physiological state.

Positron-emission tomography for hepatocellular carcinoma: Current status and future prospects

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer mortality worldwide. Various imaging modalities provide important information about HCC for its clinical management. Since positron-emission tomography (PET) or PET-computed tomography was introduced to the oncologic setting, it has played crucial roles in detecting, distinguishing, accurately staging, and evaluating local, residual, and recurrent HCC. PET imaging visualizes tissue metabolic information that is closely associated with treatment. Dynamic PET imaging and dual-tracer have emerged as complementary techniques that aid in various aspects of HCC diagnosis. The advent of new radiotracers and the development of immuno-PET and PET-magnetic resonance imaging have improved the ability to detect lesions and have made great progress in treatment surveillance. The current PET diagnostic capabilities for HCC and the supplementary techniques are reviewed herein.

DNA repair capacity correlates with standardized uptake values from 18F-fluorodeoxyglucose positron emission tomography/CT in patients with advanced non-small-cell lung cancer

Objective

The DNA repair capacity (DRC) of tumor cells is an important contributor to resistance to radiation and platinum-based drugs. Because DRC may be affected by tumor cell metabolism, we measured DRC in lymphocytes from patients with non–small-cell lung cancer (NSCLC) and compared the findings with the maximum standardized uptake value (SUV_max) on¹⁸F-fluorodeoxyglucose positron emission tomography (FDG PET) after (chemo)radiation therapy.

Methods

This study included 151 patients with stage IA-IV NSCLC who had FDG PET at a single institution and donated blood samples before chemotherapy. We assessed the correlation of DRC, measured in peripheral T lymphocytes by a host-cell reactivation assay with SUV_max and their associations with overall survival (OS) time by hazards ratios calculated with a Cox proportional hazards regression model.

Results

SUV_max of the primary tumor at diagnosis was inversely associated with lymphocyte DRC (r = −0.175, P = 0.032), particularly among patients with advanced disease (r = −0.218, P = 0.015). However, ΔSUV_max of primary tumor was not significantly associated with DRC (r = 0.005, P = 0.968). SUV_max of regional lymph nodes at diagnosis (r = −0.307, P = 0.0008) and after (chemo)radiation treatment (r = −0.329, P = 0.034) and SUV_max of the primary tumor after (chemo)radiation treatment (r = −0.253, P = 0.045) were also inversely associated with OS time.

Conclusion

DRC was inversely associated with primary tumor SUV_max before treatment but not with ΔSUV_max after (chemo)radiation.

2-Deoxyglucose and sorafenib synergistically suppress the proliferation and motility of hepatocellular carcinoma cells

Cancer cells consume more glucose than normal cells, mainly due to their increased rate of glycolysis. 2-Deoxy-d-glucose (2DG) is an analogue of glucose, and sorafenib is a kinase inhibitor and molecular agent used to treat hepatocellular carcinoma (HCC). The present study aimed to demonstrate whether combining 2DG and sorafenib suppresses tumor cell proliferation and motility more effectively than either drug alone. HLF and PLC/PRF/5 HCC cells were incubated with sorafenib with or without 1 µM 2DG, and subjected to a proliferation assay. A scratch assay was then performed to analyze cell motility following the addition of 2DG and sorafenib in combination, and each agent alone. RNA was isolated and subjected to reverse transcription-quantitative polymerase chain reaction to analyze the expression of cyclin D1 and matrix metalloproteinase-9 (MMP9) following the addition of 2DG and sorafenib in combination and each agent alone. Proliferation was markedly suppressed in cells cultured with 1 µM 2DG and 30 µM sorafenib compared with cells cultured with either agent alone (P<0.05). In addition, levels of Cyclin D1 expression decreased in cells exposed to 3 µM sorafenib and 1 µM 2DG compared with cells exposed to 2DG or sorafenib alone (P<0.05). Scratch assay demonstrated that the distance between the growing edge of the cell sheet and the scratched line was shorter in cells cultured with sorafenib and 2DG than in cells cultured with 2DG or sorafenib alone (P<0.05). Levels of MMP9 expression decreased more in cells treated with both sorafenib and 2DG than in cells treated with 2DG or sorafenib alone (P<0.05). Therefore, 2DG and sorafenib in combination suppressed the proliferation and motility of HCC cells more effectively than 2DG or sorafenib alone, and a cancer treatment combining both drugs may be more effective than sorafenib alone.

Targeting Hepatocellular Carcinoma: What did we Discover so Far?

Hepatocellular carcinoma (HCC) is increasingly considered an issue of global importance. Its rates of incidence and mortality have been markedly increasing over the last decades. Among risk factors, some should be highlighted, namely the infections by hepatitis B and C virus, as well as clinical cases of cirrhosis. HCC is characterized as asymptomatic disease in the initial stages which most often leads to a late diagnosis. At molecular and genetic level HCC represents a highly complex tumor entity, including a wide variety of mutations, thus accounting for different mechanisms of resistance towards therapeutic approaches. In particular, mutations of the TP53 gene, as well as a deregulation between the expression of pro- and anti-apoptotic proteins of the BCL-2 family are observed. Regarding treatment modalities, surgical procedures offer the best chance of cure, however, due to a late diagnosis, most of concerned patients cannot be subjected to them. Chemotherapy and radiotherapy are also ineffective, and currently, the treatment with sorafenib is the most commonly used systemic therapy although it can only increase the patient survival for some months. In this sense, a quick and accurate investigation is of utmost importance in order to develop ways of early diagnosis as well as new therapies for HCC.

Liver diseases: what is known so far about the therapy with human amniotic membrane?

Liver, the largest intern organ of the human body, is responsible for several vital tasks such as digestive and excretory functions, as well as for nutrients storage and metabolic functions, synthesis of new molecules and purification of toxic chemicals. Cirrhosis, fibrosis and hepatocellular carcinoma are the most prevalent liver diseases. Despite all the studies performed so far, treatment options for these diseases are very limited. For this reason, it is urgent to find effective therapies for these pathologies. Several studies have been performed during the last decade about the possible application of human amniotic membrane in hepatic diseases therapy. Promising results about human amniotic membrane or its derived cells, in vitro and in vivo, applications in fibrosis, cirrhosis and hepatocellular carcinoma were already published. Since it is an attractive study area, it is becoming a dynamic scientific subject. However, the action mechanisms of human amniotic membrane and its derived cells in hepatic diseases therapy must be precisely known in order that this promising therapy could be clinically used.

Impairment of oxidative phosphorylation increases the toxicity of SYD-1 on hepatocarcinoma cells (HepG2)

Toxicity of the SYD-1 mesoionic compound (3-[4-chloro-3-nitrophenyl]-1,2,3-oxadiazolium-5-olate) was evaluated on human liver cancer cells (HepG2) grown in either high glucose (HG) or galactose (GAL) medium, and also on suspended cells kept in HG medium. SYD-1 was able to decrease the viability of cultured HepG2 cells in a dose-dependent manner, as assessed by MTT, LDH release and dye with crystal violet assays, but no effect was observed on suspended cells after 1-40 min of treatment. Respiration analysis was performed after 2 min (suspended cells) or 24 h (cultured cells) of treatment: no change was observed in suspended cells, whereas SYD-1 inhibited as well basal, leak and uncoupled states of the respiration in cultured cells with HG medium. These inhibitions were consistent with the decrease in pyruvate level and increase in lactate level. Even more extended results were obtained with HepG2 cells grown in GAL medium where, additionally, the ATP amount was reduced. Furthermore, SYD-1 appears not to be transported by the main ABC multidrug transporters. These results show that SYD-1 is able to change the metabolism of HepG2 cells, and suggest that its cytotoxicity is related to impairment of mitochondrial metabolism. Therefore, we may propose that SYD-1 is a potential candidate for hepatocarcinoma treatment.

Oxidative Stress, DNA, Cell Cycle/Cell Cycle Associated Proteins and Multidrug Resistance Proteins: Targets of Human Amniotic Membrane in Hepatocellular Carcinoma

The anticancer effects of human amniotic membrane (hAM) have been studied over the last decade. However, the action mechanisms responsible for these effects are not fully understood until now. Previously results reported by our team proved that hAM is able to induce cytotoxicity and cell death in hepatocellular carcinoma (HCC), a worldwide high incident and mortal cancer. Therefore, this experimental study aimed to investigate the cellular targets of hAM protein extracts (hAMPE) in HCC through in vitro studies. Our results showed that hAMPE is able to modify oxidative stress environment in all HCC cell lines, as well as its cell cycle. hAMPE differently targets deoxyribonucleic acid (DNA), P21, P53, β-catenin and multidrug resistance (MDR) proteins in HCC cell lines. In conclusion, hAMPE has several targets in HCC, being clear that the success of this treatment depends of a personalized therapy based on the biological and genetic characteristics of the tumor.

New Approach for Treatment of Primary Liver Tumors: The Role of Quercetin

Hepatocellular carcinoma (HCC) is the most common primary liver tumor (PLT), with cholangiocarcinoma (CC) being the second most frequent. Glucose transporter 1 (GLUT-1) expression is increased in PLTs and therefore it is suggested as a therapeutic target. Flavonoids, like quercetin, are GLUT-1 competitive inhibitors and may be considered as potential therapeutic agents for PLTs. The objective of this study was evaluation of quercetin anticancer activity in three human HCC cell lines (HepG2, HuH7, and Hep3B2.1-7) and in a human CC cell line (TFK-1). The possible synergistic effect between quercetin and sorafenib, a nonspecific multikinase inhibitor used in clinical practice in patients with advanced HCC, was also evaluated. It was found that in all the cell lines, quercetin induced inhibition of the metabolic activity and cell death by apoptosis, followed by increase in BAX/BCL-2 ratio. Treatment with quercetin caused DNA damage in HepG2, Hep3B2.1-7, and TFK-1 cell lines. The effect of quercetin appears to be independent of P53. Incubation with quercetin induced an increase in GLUT-1 membrane expression and a consequent reduction in the cytoplasmic fraction, observed as a decrease in (18)F-FDG uptake, indicating a GLUT-1 competitive inhibition. The occurrence of synergy when sorafenib and quercetin were added simultaneously to HCC cell lines was noticed. Thus, the use of quercetin seems to be a promising approach for PLTs through GLUT-1 competitive inhibition.

Influence of P53 on the radiotherapy response of hepatocellular carcinoma

Background/Aims

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and it has a poor prognosis and few therapeutic options. Radiotherapy is one of the most effective forms of cancer treatment, and P53 protein is one of the key molecules determining how a cell responds to radiotherapy. The aim of this study was to determine the therapeutic efficacy of iodine-131 in three human HCC cell lines.

Methods

Western blotting was used to measure P53 expression. The effects of radiotherapy with iodine-131 were assessed by using the clonogenic assay to evaluate cell survival. Flow cytometry was carried out to examine the effects of iodine-131 on cell death, oxidative stress, reduced intracellular glutathione expression, the mitochondrial membrane potential, and the cell cycle.

Results

The P53 protein was not expressed in Hep3B2.1-7 cells, was expressed at normal levels in HepG2 cells, and was overexpressed in HuH7 cells. P53 expression in the HuH7 and HepG2 cell lines increased after internal and external irradiation with iodine-131. Irradiation induced a decrease in cell survival and led to a decrease in cell viability in all of the cell lines studied, accompanied by cell death via late apoptosis/necrosis and necrosis. Irradiation with 131-iodine induced mostly cell-cycle arrest in the G0/G1 phase.

Conclusions

These results suggest that P53 plays a key role in the radiotherapy response of HCC.

Selective Cytotoxicity of 1,3,4-Thiadiazolium Mesoionic Derivatives on Hepatocarcinoma Cells (HepG2)

In this work, we evaluated the cytotoxicity of mesoionic 4-phenyl-5-(2-Y, 4-X or 4-X-cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride derivatives (MI-J: X=OH, Y=H; MI-D: X=NO2, Y=H; MI-4F: X=F, Y=H; MI-2,4diF: X=Y=F) on human hepatocellular carcinoma (HepG2), and non-tumor cells (rat hepatocytes) for comparison. MI-J, M-4F and MI-2,4diF reduced HepG2 viability by ~ 50% at 25 μM after 24-h treatment, whereas MI-D required a 50 μM concentration, as shown by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. The cytotoxicity was confirmed with lactate dehydrogenase assay, of which activity was increased by 55, 24 and 16% for MI-J, MI-4F and MI-2,4diF respectively (at 25 μM after 24 h). To identify the death pathway related to cytotoxicity, the HepG2 cells treated by mesoionic compounds were labeled with both annexin V and PI, and analyzed by flow cytometry. All compounds increased the number of doubly-stained cells at 25 μM after 24 h: by 76% for MI-J, 25% for MI-4F and MI-2,4diF, and 11% for MI-D. It was also verified that increased DNA fragmentation occurred upon MI-J, MI-4F and MI-2,4diF treatments (by 12%, 9% and 8%, respectively, at 25 μM after 24 h). These compounds were only weakly, or not at all, transported by the main multidrug transporters, P-glycoprotein, ABCG2 and MRP1, and were able to slightly inhibit their drug-transport activity. It may be concluded that 1,3,4-thiadiazolium compounds, especially the hydroxy derivative MI-J, constitute promising candidates for future investigations on in-vivo treatment of hepatocellular carcinoma.

Influence of P-Glycoprotein Inhibition or Deficiency at the Blood-Brain Barrier on (18)F-2-Fluoro-2-Deoxy-D-glucose ( (18)F-FDG) Brain Kinetics

The fluorinated D-glucose analog (18)F-2-fluoro-2-deoxy-D-glucose ((18)F-FDG) is the most prevalent radiopharmaceutical for positron emission tomography (PET) imaging. P-Glycoprotein's (P-gp, MDR1, and ABCB1) function in various cancer cell lines and tumors was shown to impact (18)F-FDG incorporation, suggesting that P-gp function at the blood-brain barrier may also modulate (18)F-FDG brain kinetics. We tested the influence of P-gp inhibition using the cyclosporine analog valspodar (PSC833; 5 μM) on the uptake of (18)F-FDG in standardized human P-gp-overexpressing cells (MDCKII-MDR1). Consequences for (18)F-FDG brain kinetics were then assessed using (i) (18)F-FDG PET imaging and suitable kinetic modelling in baboons without or with P-gp inhibition by intravenous cyclosporine infusion (15 mg kg(-1) h(-1)) and (ii) in situ brain perfusion in wild-type and P-gp/Bcrp (breast cancer resistance protein) knockout mice and controlled D-glucose exposure to the brain. In vitro, the time course of (18)F-FDG uptake in MDR1 cells was influenced by the presence of valspodar in the absence of D-glucose but not in the presence of high D-glucose concentration. PET analysis revealed that P-gp inhibition had no significant impact on estimated brain kinetics parameters K 1, k 2, k 3, V T , and CMRGlc. The lack of P-gp effect on in vivo (18)F-FDG brain distribution was confirmed in P-gp/Bcrp-deficient mice. P-gp inhibition indirectly modulates (18)F-FDG uptake into P-gp-overexpressing cells, possibly through differences in the energetic cell level state. (18)F-FDG is not a P-gp substrate at the BBB and (18)F-FDG brain kinetics as well as estimated brain glucose metabolism are influenced by neither P-gp inhibition nor P-gp/Bcrp deficiencies in baboon and mice, respectively.