Subcellular daunorubicin distribution and its relation to multidrug resistance phenotype in drug-resistant cell line SMMC-7721/R

Effect of GnT-V knockdown on the proliferation, migration and invasion of the SMMC7721/R human hepatocellular carcinoma drug-resistant cell line

Hepatocellular carcinoma (HCC) is a commonly occurring malignant tumor, with a high incidence rate. The present study aimed to investigate the effect of knocking down the N‑glycosyltransferase‑V (GnT‑V) protein on the proliferation, migration and invasion of the human HCC drug‑resistant cell line, SMMC7721/R. SMMC7721/R cells with GnT‑V‑knockdown (SMMC‑7721/R‑GnT‑V) were constructed using the method of lentiviral transfection. The expression of GnT‑V was assessed using reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blotting. Cell proliferation was determined using an MTT assay, and the extent of cellular apoptosis was assessed using flow cytometric analysis. Additionally, the metastatic ability of the cells in vitro was analyzed using cell adhesion and invasion assays. Western blotting was used to investigate the protein expression levels of caspase‑3, caspase‑9, Bcl‑2, Bax, matrix metalloproteinase (MMP)‑2 and MMP‑9, and RT‑qPCR was used to determine the mRNA expression levels of the genes for the breast cancer resistance protein and P‑glycoprotein in the SMMC‑7721/R cells. Taken together, the results of the present study revealed that the knockdown of GnT‑V significantly suppressed the proliferation, migration and invasion (P<0.05) of the SMMC‑7721/R cells. Furthermore, the possible mechanism underlying these phenomena may be associated with the induction of mitochondria‑mediated apoptosis, inhibition of the degradation of the extracellular matrix and an enhancement of the drug-sensitivity. GnT‑V‑knockdown may therefore be used to treat drug‑resistant HCC in the future.

Drug and gene co-delivery systems for cancer treatment

Cancer remains a major killer and a leading cause of death in the world; thus, a growing number of new treatments have been focused on cancer therapy over the past few decades. Chemotherapy, which is thought to be a powerful strategy for cancer treatment, has been widely used in clinical therapy in recent years. However, due to the complexity of cancer, a single therapeutic approach is insufficient for the suppression of cancer growth and migration. Therefore, increasing attention has been paid to the use of smart multifunctional carriers and combinatorially delivers chemotherapeutic drugs and functional genes in order to maximize therapeutic efficiency. Combination therapy using selected drugs and genes can not only overcome multidrug resistance and inhibit the cellular anti-apoptotic process but also achieve a synergistic therapeutic effect. Because multifunctional nanocarriers are important for achieving these goals, this review will illustrate and discuss some advanced biomaterial nanocarriers for co-delivering therapeutic genes and drugs, including multifunctional micelles, liposomes, polymeric conjugates and inorganic nanoparticles. In addition, the challenges and future perspectives for co-delivery systems, containing therapeutic drugs and genes to achieve better therapeutic effects for cancer treatment will be discussed.

Enhancement of the efficacy of chemotherapy for lung cancer by simultaneous suppression of multidrug resistance and antiapoptotic cellular defense: novel multicomponent delivery system

The efficacy of chemotherapy of lung cancer is limited by the development of resistance in cancer cells during treatment. In most lung cancers, this resistance is associated with the overexpression of (a) multidrug resistance-associated protein (MRP) responsible for drug efflux from the cancer cells (pump resistance) and (b) BCL2 protein that activates antiapoptotic cellular defense (nonpump resistance). A novel liposomal proapoptotic anticancer drug delivery system was developed to enhance anticancer efficacy of the well-established drug doxorubicin (DOX). This multicomponent drug delivery system was tested on multidrug-sensitive and -resistant human small-cell lung cancer cells. The drug delivery system includes four components: (a) liposome as a carrier, (b) DOX as an inductor of apoptosis, (c) antisense oligonucleotides (ASOs) targeted to MRP1 mRNA as a suppressor of pump resistance, and (d) ASOs targeted to BCL2 mRNA as a suppressor of nonpump resistance. Intracellular internalization of ASOs and DOX; the influence of the proposed system on the expression of genes and proteins involved in the multidrug resistance, cytotoxicity, and apoptosis induction and antiapoptotic defense; and the activity of caspases were studied. It was found that the proposed liposomal delivery system successfully delivered ASOs and DOX to cell nuclei, inhibited MRP1 and BCL2 protein synthesis, and substantially increased the anticancer action of DOX by stimulating the caspase-dependent pathway of apoptosis in multidrug-resistant human lung cancer cells.

Effects of indomethacin and/or casplatin on apoptosis of gastric cancer cells

AIM: To investigate the effects of indomethacin (IN) and casplain (CDDP) on apoptosis of gastric cancer cell line MGC803 and to provide the theoretic basis for gastric cancer therapy.

METHODS: Gastric cancer MGC803 cells were treated with IN and /or CDDP. Proliferation of the cells was detected by using MTT assay. Apoptosis of cells was measured by using fluorescence staining, and cell cycle kinetics by flow cytometry.

RESULTS: Both IN and CDDP were able to restrain the proliferation and induce apoptosis of the cells. There was dose-dependent and time-dependent cell proliferation induced by IN. High concentration of CDDP (10 mg/L) had also the time-effect, but a low dose of CDDP (0.1, 1 mg/L) did not. The percentage of apoptotic cells did not changed after 24h incubation with a low dose of CDDP. There also existed good dose-dependent and time-dependent effects when every concentration of CDDP combined with moderate dose IN (200 mmol/L). Low dose CDDP with IN had the similar effect to that of high dose CDDP alone.

CONCLUSION: IN and CDDP have the synergistic action when they work together on gastric cancer cell line MGC-803 and perhaps IN can antagonize the chemo-resistance of gastric cancer to other chemical drugs.

Inhibitory effects of celecoxib on proliferation of human liver and gastric carcinoma cells in vitro

AIM: To study the inhibitory effects of celecoxib on proliferation of human hepatoma SMMC-7721 cells and gastric cancer SGC-7901 cells in vitro.

METHODS: The two carcinoma cells were cultured with celecoxib at various concentrations(0, 20, 40, 80, 160 and 320 mmol/L). Growth suppression was detected with MTT colorimetric assay, cell apoptotic alterations were evaluated by transmission electron microscopy(TEM), and quantity of Cox-2 was evaluated by cytochemical staining.

RESULTS: The inhibition of proliferation on two carcinoma cells was observed(49.1% and 42.9% by 320 mmol/L celecoxib). The inhibitory effect was dose-dependent. Apoptotic cells were observed under transmission electron microscope. The different quantities of Cox-2 protein in cells were observed by cytochemical staining.

CONCLUSION: Celecoxib inhibits proliferation, induces apoptosis of human two carcinoma cells in vitro, and the effects have close relation to the quantities of Cox-2 protein in cells.

Gonadotropin hormone-releasing hormone analog induces apoptosis in human hepatocarcinoma cell in vitro

AIM

To induce apoptosis of human cultured hepatocellular carcinoma (HCC) cell line SMMC-7721 by GnRH-analog alarelin, and to provide the experimental evidence for GnRH-A in endocrinotherapy of HCC.

METHODS

MTT assay, transmission electron microscopy and DNA end labeling method were used to identify apoptosis of cultured human hepatocellular carcinoma cells treated by alarelin.

RESULTS

SMMC-7721 cell line was induced by alarelin in 10-9 mol/L concentration. The induction of apoptosis was dose-effect dependent. Under electron microscopy we could identify the earlier and later stage of apoptotic cells, and chromatin condensation, as well as apoptosis body formation. DNA end labeling method showed that alarelin could induce apoptosis of HCC cells (0.29±0.06 vs 0.11±0.03), and their apoptosis body formations were observed. Compared with control group, the TUNEL index was increased significantly in alarelin treated groups (P <0.05).

CONCLUSION

GnRH-analog alarelin can induce apoptosis of cultured human HCC cell line SMMC-7721, and it plays a potential role in the treatment of human HCC.

Effect of arsenic trioxide on rat hepatocarcinoma and its renal cytotoxicity

AIM: To study the effect of arsenic trioxide (As₂O₃) on rat experimental hepatocarcinoma and its renal cytotoxicity.

METHODS: The hepatocarcinoma model was established by diethaylnitrosamine perfusion in stomach of 120 Wistar rats, and the treatment began at the end of 20 weeks. Before the treatment, the rat models were randomly divided into 5 groups. In the treatment groups, three doses of As₂O₃ were injected into rat abdominal cavity, the total time of drug administration was 4 weeks. Cisplatin control or the blank group was injected into abdominal cavity with equal amount of cisplatin or saline at the same time, respectively. On the 7^th, 14^th and 28^th day after the treatment, the hepatocarcinoma nodules were obtained and the morphologic changes of hepatocarcinoma cells were observed under light and electron microscopes; Immunohistochemistry (S-P methods) was employed to detect the expression of bcl-2, bax and PCNA in hepatocarcinoma tissues; flow cytometry (TUNEL assay) was used to detect the apoptosis of liver cancer cells and the change of cytokinetics. On the 28^th day, the kidneys were obtained and their histologic changes were observed under light microscope, and immunohistochemistry (SP stain) was also employed to detect the expression of bcl-2 and PCNA. Cisplatin and saline solution were used as the control.

RESULTS: As₂O₃ could induce the apoptosis of rat liver cancer cells and exhibited typical morphologic changes. The incidence of apoptosis of hapatocarcinoma cells was elevated (P = 0.001). The elevation was the most higher in the group of middle-dose of As₂O₃ (1 mg·kg^-1), significantly higher than that of the other arsenic groups and the controls (P = 0.001). Large dose of As₂O₃ (5 mg·kg^-1) was able to arise the incidence of apoptosis, but also produced a large amount of necrosis and inflammatory reaction. Middle dose of As₂O₃ dramatically increased the cell number in G2/M phase (P = 0.0001), and apoptosis happened apparently. The expression of bcl-2 and bax was related to the dose of As₂O₃. With the up-regulation of apoptotic incidence, the ratio of bcl-2/bak decreased. But the incidence of apoptosis was not the highest status and the ratio of bcl-2/bax was at the lowest when the highest-dose of As₂O₃ was used. There was significant difference among the PCNA indexes (PCNA L1) of the five groups. Of them, three arsenic groups all showed decrease of different degrees, and this down-regulation was most obvious in group A. There was significant difference among the three groups (P = 0.016). Under the light microscope, the rat kidney in the cisplatin group exhibited tubular epithelium swelling and degeneration, protein casts in collecting tubules; While all arsenic groups didn’t show the significant changes (P = 0.013). In the arsenic groups, the expression of bcl-2 in the renal tubular epithelium was increased (P = 0.005), no obvious changes happened to PCNA L1. But in the group of cisplatin, the PCNA L1 increased significantly (P = 0.001).

CONCLUSION: As₂O₃ can induce apoptosis of rat hepatocellular carcinoma cells. And there is optimum dose; too high dose will induce the cytotoxic effect, while certain dose of As₂O₃ is able to block the cell cycle at G2/M phase. As₂O₃ had the most remarkable influence on G2/M cells, and it can also induce apoptosis to cells at other phases. As₂O₃ can restrain the proliferation of rat hepatocellular carcinoma cells, in a dose-time dependent manner. Compared with cisplatin, As₂O₃ didn’t show obvious renal toxicity, which was related to the increasing expression of bcl-2 in renal tubular epithelium, the inhibition of apoptosis and the anti-oxidation effects.