Therapeutic effects of 5-fluorouracil microspheres on peritoneal carcinomatosis induced by Colon 26 or B-16 melanoma in mice

Establishment of patient-derived xenograft model of peritoneal mucinous carcinomatosis with signet ring cells and in vivo study on the efficacy and toxicity of intraperitoneal injection of 5-fluorouracil

BACKGROUND

Pseudomyxoma peritonei (PMP) is an indolent malignancy and insensitive to systemic chemotherapy. The authors established patient-derived xenograft (PDX) model of PMP, and evaluated the efficacy and toxicity of intraperitoneal (i.p.) administration of 5-fluorouracil (5-FU) in this model.

METHODS

Human PMP sample was collected to establish subcutaneous (s.c.) and i.p.

MODEL

In vivo study of i.p. injection of 5-FU was performed in i.p. model, with experimental peritoneal cancer index (ePCI) score and pathological examinations for evaluating the efficacy and toxicity.

RESULTS

Both s.c. and i.p. models were constructed. The average passage interval of s.c. model was 44.2 ± 5.2 days, and the i.p. model was characterized by disseminated solid tumor nodules in abdominal-pelvic cavity. Both models were diagnosed as peritoneal mucinous carcinomatosis with signet ring cells (PMCA-S). Immunohistochemical characteristics was similar to human. GNAS mutation was detected in both model and patient. In the in vivo study, average ePCI of treatment group was lower than control and vehicle group (P = .004). Histopathology revealed obvious tumor necrosis in treatment group, and decreased Ki67 positive rate (P = .010). In toxicity study, 5-FU significantly influenced body weight (P = .010) and 1 animal from treatment group died on day 14. Congestive splenomegaly was observed (88.9%). Hepatotoxicity presented as acidophilic body (55.6%), cholestasis (100%), bile canaliculus hyperplasia and obstruction (22.2%), and lymphocyte accumulation (77.8%).

CONCLUSIONS

PDX model of PMCA-S was established successfully, and i.p. 5-FU could inhibit tumor proliferation and progression, with decreased Ki67 positive rate and ePCI score. Hepatotoxicity was the main side effect.

Anti-hepatocarcinoma effects of 5-fluorouracil encapsulated by galactosylceramide liposomes in vivo and in vitro

AIM: To study the anti-hepatocarcinoma effects of 5-fluorouracil (5-Fu) encapsulated by galactosylceramide liposomes (5-Fu-GCL) in vivo and in vitro.

METHODS: Tumor-bearing animal model and HepA cell line were respectively adopted to evaluate the anti-tumor effects of 5-Fu-GCL in vivo and in vitro. Tumor cell growth inhibition effects of 5-Fu-GCL in vitro were assessed by cell viability assay and MTT assay. In vivo experiment, the inhibitory effects on tumor growth were evaluated by tumor inhibition rate and animal survival days. High performance liquid chromatography was used to detect the concentration-time course of 5-Fu-GCL in intracellular fluid in vitro and the distribution of 5-Fu-GCL in liver tumor tissues in vivo. Apoptosis and cell cycle of tumor cells were demonstrated by flow cytometry.

RESULTS: In vitro experiment, 5-Fu-GCL (6.25-100 μmol/L) and free 5-Fu significantly inhibited HepA cell growth. Furthermore, IC₅₀ of 5-Fu-GCL (34.5 μmol/L) was lower than that of free 5-Fu (51.2 μmol/L). In vivo experiment, 5-Fu-GCL (20, 40, 80 mg/kg) significantly suppressed the tumor growth in HepA bearing mice model. Compared with free 5-Fu, the area under curve of 5-Fu-GCL in intracellular fluid increased 2.6 times. Similarly, the distribution of 5-Fu-GCL in liver tumor tissues was significantly higher than that of free 5-Fu. After being treated with 5-Fu-GCL, the apoptotic rate and the proportion of HepA cells in the S phase increased, while the proportion in the G0/G1 and G2/M phases decreased.

CONCLUSION: 5-Fu-GCL appears to have anti-hepato-carcinoma effects and its drug action is better than free 5-Fu. Its mechanism is partly related to increased drug concentrations in intracellular fluid and liver tumor tissues, enhanced tumor cell apoptotic rate and arrest of cell cycle in S phase.

Pharmacokinetics and tissue distribution of 5-fluorouracil encapsulated by galactosylceramide liposomes in mice

AIM

To study the pharmacokinetics and tissue distribution of 5-fluorouracil encapsulated by galactosylceramide liposomes (5-Fu-GCL) in mice.

METHODS

The concentration of 5-fluorouracil (5-Fu) in serum was detected by high performance liquid chromatography after 5-Fu-GCL (80, 40, 20 mg/kg) and free 5-Fu (40 mg/kg) were injected intravenously into mice. The tissue distribution of 5-Fu-GCL (40 mg/kg) and free 5-Fu (40 mg/kg) was investigated, and concentration-time profile of the two preparations in the liver were studied. Data were analyzed by 3p97 program.

RESULTS

Serum concentration-time curves of 5-Fu-GCL and free 5-Fu conformed to one compartment model of first order absorption. 5-Fu-GCL at 80, 40, and 20 mg/kg had T(1/2Ke) of 25.8+/-4.2, 27.3+/-4.4, and 28.2+/-5.6 min; C0 of 24.9+/-4.9, 17.7+/-3.6, and 11.5+/-2.7 mg/L; and AUC of 990.0+/-45.2,622.5+/-38.3, and 340.4+/-25.6 mg x min x L(-1), respectively. In contrast free 5-Fu at 40 kg/mg had T(1/2Ke) of 15.8+/-2.2 min, C0 of 35.8+/-6.2 mg/L, AUC of 639.0+/-35.9 mg x min x L(-1). The tissue distribution of 5-Fu-GCL in the liver and immune organs was significantly increased, while in heart and kidney it was remarkably decreased. The AUC of 5-Fu-GCL in the liver was 3 times higher than that of free 5-Fu.

CONCLUSION

The pharmacokinetics and tissue distribution of 5-Fu-GCL appears to be linear-related and dose-dependent, and exhibits sustained-release and hepatic target characteristics.

Delivery of an anticancer drug and a chemosensitizer to murine breast sarcoma by intratumoral injection of sulfopropyl dextran microspheres

Intratumoral injection of controlled-release microsphere formulations of anticancer compounds has the potential to selectively increase tumour exposure to drugs. This work aimed to evaluate the therapeutic effect and toxicity of microsphere formulations containing the anticancer drug, doxorubicin, in a murine tumour model. The effect of co-administration of verapamil, a P-glycoprotein modulator or chemosensitizer, was investigated. Initial in-vitro studies confirmed the ability of verapamil to enhance the accumulation of both doxorubicin and [(99mTc)]sestamibi, also a P-glycoprotein substrate, in EMT6 murine breast sarcoma cells and a doxorubicin-selected multidrug-resistant variant, EMT6/AR1.0. Ex-vivo studies using confocal microscopy demonstrated release of doxorubicin from microspheres and diffusion of the drug through tissue. For in-vivo studies, EMT6 and EMT6/AR1.0 cells were grown in BALB/c mice. Following intratumoral injection of doxorubicin-loaded microspheres, alone or in combination with verapamil-loaded microspheres, the tumour diameter was measured serially as an indication of therapeutic effect, while the weight, appearance, and behaviour of the mice were monitored as an indication of general toxicity. Intratumoral injections of doxorubicin-loaded microspheres were tolerated much better than systemic administration of equivalent drug concentrations. There was a modest (up to 34%) delay of tumour growth compared with groups receiving no treatment or blank microspheres. Co-injection of verapamil microspheres with doxorubicin microspheres produced a moderate increase in toxicity but no further delay in tumour growth. Controlled-release microsphere formulations of anticancer agents administered intratumorally were an efficient way to deliver high drug doses to the tumour with little systemic toxicity.

Intraperitoneal chemotherapy for colorectal cancer

The peritoneal surface remains an important failure site for patients with colorectal cancer. Peritoneal metastases of colorectal cancer are at present considered equal to distant metastatic disease. Consequently, peritoneal carcinomatosis is treated with systemic chemotherapy and surgery only to palliate complications such as obstruction. Despite the development of new chemotherapeutic agents and combinations, the results remain disappointing with a limited impact on survival. Colorectal carcinoma cells are relatively resistant to chemotherapy. Intraperitoneal chemotherapy seems to be an attractive approach in the treatment of high-risk colorectal cancer and peritoneal carcinomatosis from colorectal origin providing high local drug concentration with limited systemic side effects. Adjuvant early postoperative intraperitoneal chemotherapy is worthwhile for consideration as treatment option after resection of high-risk colorectal cancer. In the treatment of peritoneal carcinomatosis postoperative intraperitoneal chemotherapy leads to inadequate exposure of the peritoneal surface. Only an intraoperative intraperitoneal chemotherapy performed with direct cytotoxic drugs such as MMC and cisplatin overcome this problem. The limited drug penetration in tissue implies the need for extensive cytoreductive surgery. The results of phase II studies suggest that an increased median survival can be achieved with this approach. The natural history of this disease and the heterogeneity of the patients are such that only a randomized trial design will adequately answer the question whether regional treatment of patients with peritoneal dissemination of colorectal cancer actually prolongs survival. The results of such a study are to be expected in approximately 2 years time.

In vitro investigation of ionic polysaccharide microspheres for simultaneous delivery of chemosensitizer and antineoplastic agent to multidrug-resistant cells

Insufficient intratumoral concentration of therapeutic agents and multidrug resistance are major factors responsible for failure of treatment of solid tumors. Simultaneous delivery of chemosensitizing and antineoplastic agents by microspheres could lead to enhanced chemotherapy of multidrug-resistant (MDR) tumors. Ionic polysaccharide microspheres derived from dextran were used to load chemosensitizers (e.g., verapamil) and anticancer drugs such as vinblastine. High drug loading was achieved for both a single agent and dual agents. The equilibrium drug loading was dependent on the ratio of the microspheres (MS) to the drug, as well as the relative affinity of the agents to the MS in the case of dual agents. The drug release from drug-MS involved hydration and swelling of the MS in addition to ion exchange. The effectiveness of MS-delivered chemosensitizers in the reversal of drug resistance was evaluated by measuring the uptake of [3H]vinblastine by MDR cells (CHRC5). The concomitant delivery of verapamil with vinblastine by the MS led to a 6-7-fold increase in the uptake of vinblastine, a level similar to the uptake obtained with free drug solutions. The results suggest that the antineoplastic and chemosensitizing agents were released effectively from the MS and the bioactivity of the chemosensitizer was preserved during the process.