Pharmacology and antitumour effects of intraportal pirarubicin on experimental liver metastases

Preventive and therapeutic effect of intraportal oridonin on BALb/c nude mice hemispleen model of colon cancer liver metastasis

Background

This study is to investigate the preventive and therapeutic effect of intraportal oridonin on colorectal cancer liver metastasis (CRCLM).

Methods

The inhibitory effect of oridonin on HT29 cells was determined by CCK-8 and MTT assays. The preventive and therapeutic effect of intraportal oridonin on CRCLM were investigated by establishing BALb/c nude mice hemispleen models of colon cancer liver metastasis. The microscopic characteristics of tumor tissues were observed by hematoxylin-eosin staining, immunohistochemistry and TUNEL staining. On the other hand, liver function enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), were detected to evaluate the hepatotoxicity of intraportal oridonin. The serum levels of tumor markers, including carcinoembryonic antigen (CEA) and α-fetoprotein (AFP), were used to investigate the intervention effect of intraportal oridonin on CRCLM.

Results

Oridonin exerted an inhibitory effect on the proliferation of HT29 cells in vitro. Intraportal oridonin was found to effectively prevent the occurrence and formation of CRCLM, whilst intraportal oridonin can also exert a therapeutic effect on CRCLM. Additionally, liver enzymes testing indicated that intraportal oridonin possesses non-hepatotoxicity, instead can effectively alleviate liver injury caused by tumor. Furthermore, intraportal oridonin was also revealed to decrease the serum levels of AFP and CEA.

Conclusions

Intraportal oridonin can effectively inhibit the formation of liver metastatic tumor and exert a certain degree of preventive and therapeutic effect on CRCLM. These findings indicate intraportal oridonin to be a promising anti-metastasis agent for CRCLM.

Pharmacokinetic advantage of intra-arterial hepatic oxaliplatin administration: comparative results with cisplatin using a rabbit VX2 tumor model

The aim of this study was to compare intra-arterial hepatic administration (IAH) versus i.v. administration of oxaliplatin and cisplatin in a VX2 tumor model in rabbits. VX2 tumors were implanted in the livers of White New Zealand female rabbits and 2 weeks later they received either cisplatin (4 mg/kg) or oxaliplatin (6 mg/kg) administered by IAH or i.v. Platinum pharmacokinetic parameters were measured by atomic absorption spectrometry at baseline, 2, 5 10, 20, 40 and 60 min, and then at 2, 4, 6 and 24 h after drug administration. Animals were sacrificed 24 h after drug administration to measure platinum concentrations in various tissues. After IAH oxaliplatin administration, we observed a significant decrease for total and filterable platinum in the Cmax compared with i.v. administration (12.4 versus 18.2 microg/l; p=0.02 and 11.2 versus 17.3 microg/l; p=0.02, respectively). Significant differences in various tissue concentrations were reported when comparing IAH and i.v. administration of oxaliplatin with IAH administration offering an advantage over i.v. administration. No differences in pharmacokinetic parameters or platinum tissue accumulation were apparent between the IAH and i.v. administration with cisplatin. We conclude that there is a significant pharmacokinetic advantage to using oxaliplatin for locoregional IAH chemotherapy compared with i.v. administration.

A new method for establishing an intrapulmonary tumor in the rabbit

OBJECTIVES

Local treatments against malignant intrapulmonary tumors, such as radiotherapy, photodynamic therapy, and laser ablation therapy, are sometimes used in preference to surgery or chemotherapy. The efficacy of such treatments is dependent not only on the pathological type of the primary tumor, but also on loco-regional settings such as location of the lesion and relationship between the tumor and surrounding organs as well as tissues. Therefore, in order to evaluate the efficacy of a newly developed local treatment, it is essential to have a model in which a tumor can be established at an intended location. In this study, we developed a model for the establishment of an intrapulmonary tumor, using the rabbit.

METHODS

After induction of general anaesthesia, a catheter was inserted via the airway into the lung of a Japanese white rabbit, under X-ray guidance. The lung was then inoculated with a collagen gel matrix containing a suspension of VX2 cells derived from rabbit skin squamous cell carcinoma. Subsequent tumor growth was evaluated with X-ray imaging and pathological examination.

RESULTS

Growth of a solitary tumor at the target site was pathologically confirmed in 9 of 12 rabbits that were inoculated with 1 x 10(8) cells. In addition, tumor growth could be followed in 8 of 9 rabbits by chest X-ray examination. That is, a solitary intrapulmonary tumor could be established in 8 of 12 animals (67%).

CONCLUSION

The rabbit model reported here enables establishment of a solitary intrapulmonary tumor and thus can provide a suitable experimental setting for evaluation of local treatments of intrapulmonary tumors.

In vivo drug distribution dynamics in thermoablated and normal rabbit livers from biodegradable polymers

Image-guided radiofrequency ablation combined with intratumoral drug delivery provides a novel and minimally invasive treatment of liver cancers. In this study, the in vivo transport properties of doxorubicin in thermoablated and nonablated rabbit livers were characterized and compared. Doxorubicin was released from polymer implants (millirods) to the ablated and nonablated liver tissue. At different time points, the 2D distribution profiles were quantitatively determined by a fluorescence imaging method. Analysis of the doxorubicin concentration at the ablation boundary showed that it reached a maximum of 49.8 microg/g at 24 h after implantation, which was higher than the reported cytotoxic concentration of doxorubicin (6.4 microg/g) for liver VX-2 cancer cells. This value dropped to 0.4 microg/g at 48 h after implantation due to the depletion of doxorubicin from the polymer millirod. Results also showed that the area of drug distribution was significantly larger in ablated tissue than nonablated tissue. The therapeutic penetration distance was found to be 5.2 mm in thermoablated livers, compared to 1.2 mm in nonablated livers at 24 h. This difference in drug transport properties is attributed to destruction of the vasculature network in the ablated tissue as supported by histological analysis. Consequently, drug washout by blood perfusion is hampered while drug diffusion becomes the dominant process of transport in the ablated tissue. Results from this study provide insightful information on the rational design and development of polymer millirods for intratumoral drug delivery applications.

Transcatheter arterial embolization as a method of cisplatin-retention enhancement on the VX2 tumor uterus transplants

PURPOSE

Enhanced cisplatin (Pt) retention using transcatheter arterial chemoembolization (TAE) with Gelfoam particles was studied in rabbit uterine tumors.

METHODS

Ten rabbit uteri were inoculated with 5 x 10(7) cells of VX2 carcinoma. Three to four weeks later cisplatin, 1 mg/kg, was injected, either with (TAE group) or without (IA group) being mixed with small Gelfoam particles, into the aortic bifurcation over 5 s. Blood and tissue concentration of cisplatin were determined.

RESULTS

Slower arterial blood clearance of Pt was observed in the TAE group compared with the IA group, whereas the venous blood Pt clearance curves were similar for both groups. The uterine tumor Pt concentration at 80 min was found to be 2.52-fold higher after TAE compared with IA (p < 0.01). In the pelvic metastatic lymph nodes, the Pt concentration was 4.63 times higher after TAE than after IA (p < 0.01).

CONCLUSION

These data indicate that TAE is an effective means of increasing tissue concentration in uterine tumors.

Verapamil-reversing concentrations induce blood flow changes that could counteract in vivo the MDR-1-modulating effects

BACKGROUND

Intraarterial hepatic (IAH) administration of verapamil should achieve mdr-1-reversing concentrations with reduced cardiac toxicity. The authors have explored the tolerance of its IAH administration and its effects on doxorubicin pharmacodymamics.

METHODS

Verapamil was given to rabbits by intravenous or IAH administration, and its effects on heart rates were compared. Doxorubicin then was given intravenously either with IAH verapamil or with an IAH control perfusion, and tumor and liver drug concentrations were determined. Hepatic blood flow changes were studied by the administration of 99mTc-albumin macroaggregates (99mTc-MAA) under verapamil IAH perfusions.

RESULTS

Compared with the intravenous route, IAH administration of verapamil was not toxic, and cardiac effects were reduced significantly. Its effect on doxorubicin distribution was detrimental, because the tumor-liver doxorubicin concentration ratios were lower in the verapamil group (0.23 vs. 3.37; P < 0.05). Tumor doxorubicin concentrations were lower when verapamil was coinfused (43 vs. 573 ng/100 mg tissue; P < 0.05). In normal liver tissue, increased amounts of doxorubicin and metabolites were observed. The verapamil IAH perfusions with 99mTc-MAA confirmed a differential action on tumor and normal vessels; the distribution of radionuclide was diverted away from the tumor bed significantly when verapamil was administered (tumor-to-liver ratio of 25.3 control rabbits vs. 5.99 rabbits who received verapamil; P < 0.05).

CONCLUSIONS

Reversing the concentrations of verapamil provoked changes in the distribution of the liver blood flow. The hemodynamic effects of verapamil regional perfusions could counteract in vivo its potential mdr-1-reversing properties.