Antitumor activity of hyperthermia alone or in combination with cisplatin and melphalan in primary cultures of human malignant melanoma

The Rationale for "Laser-Induced Thermal Therapy (LITT) and Intratumoral Cisplatin" Approach for Cancer Treatment

Cisplatin is one of the most widely used anticancer drugs in the treatment of various types of solid human cancers, as well as germ cell tumors, sarcomas, and lymphomas. Strong evidence from research has demonstrated higher efficacy of a combination of cisplatin and derivatives, together with hyperthermia and light, in overcoming drug resistance and improving tumoricidal efficacy. It is well known that the antioncogenic potential of CDDP is markedly enhanced by hyperthermia compared to drug treatment alone. However, more recently, accelerators of high energy particles, such as synchrotrons, have been used to produce powerful and monochromatizable radiation to induce an Auger electron cascade in cis-platinum molecules. This is the concept that makes photoactivation of cis-platinum theoretically possible. Both heat and light increase cisplatin anticancer activity via multiple mechanisms, generating DNA lesions by interacting with purine bases in DNA followed by activation of several signal transduction pathways which finally lead to apoptosis. For the past twenty-seven years, our group has developed infrared photo-thermal activation of cisplatin for cancer treatment from bench to bedside. The future development of photoactivatable prodrugs of platinum-based agents injected intratumorally will increase selectivity, lower toxicity and increase efficacy of this important class of antitumor drugs, particularly when treating tumors accessible to laser-based fiber-optic devices, as in head and neck cancer. In this article, the mechanistic rationale of combined intratumor injections of cisplatin and laser-induced thermal therapy (CDDP-LITT) and the clinical application of such minimally invasive treatment for cancer are reviewed.

Hyperthermia Enhances Doxorubicin Therapeutic Efficacy against A375 and MNT-1 Melanoma Cells

Melanoma is the deadliest form of skin cancer, and its incidence has alarmingly increased in the last few decades, creating a need for novel treatment approaches. Thus, we evaluated the combinatorial effect of doxorubicin (DOX) and hyperthermia on A375 and MNT-1 human melanoma cell lines. Cells were treated with DOX for 24, 48, and 72 h and their viabilities were assessed. The effect of DOX IC10 and IC20 (combined at 43 °C for 30, 60, and 120 min) on cell viability was further analyzed. Interference on cell cycle dynamics, reactive oxygen species (ROS) production, and apoptosis upon treatment (with 30 min at 43 °C and DOX at the IC20 for 48 h) were analyzed by flow cytometry. Combined treatment significantly decreased cell viability, but not in all tested conditions, suggesting that the effect depends on the drug concentration and heat treatment duration. Combined treatment also mediated a G2/M phase arrest in both cell lines, as well as increasing ROS levels. Additionally, it induced early apoptosis in MNT-1 cells, while in A375 cells this effect was similar to the one caused by hyperthermia alone. These findings demonstrate that hyperthermia enhances DOX effect through cell cycle arrest, oxidative stress, and apoptotic cell death.

Toxicity and morbility after isolated lower limb perfusion in 242 chemo-hyperthermal treatments for cutaneous melanoma: the experience of the Tuscan Reference Centre

BACKGROUND

The aim of this retrospective study was to assess the results concerning the regional and systemic toxicity and complications in 242 chemo-hyperthermal treatments (HILPs) for lower limb melanoma.

PATIENTS AND METHODS

60 HILPs (G-A) were performed with mild HT plus L-PAM (10 mg/lt) +/- D-actimomycin; 74 HILPs (G-B) with true HT (40-41.8 degrees C) plus L-PAM (10 mg/lt) +/- D-act; 108 HILPs (G-C) with true HT plus L-PAM (10 mg/lt) +/- D-act plus L-PAM (5 mg/lt) additional bolus.

RESULTS

Limb toxicity was very low in G-A and in G-B; increasing toxicity (grade III = 37%) in G-C; no grade IV statistical difference was registered in all three groups, with percentage values among 1.6% and 2.7%. Systemic toxicity showed itself only in the haemopoietic parameters. No differences were registered in G-B vs G-A group. In G-C vs G-B a significative increase of systemic toxicity was seen in grade 3 (p < 0.05). Postoperative complications were acceptable. Local and systemic side-effects were transient; no permanent neurological limb deficit was registered. The postoperative mortality was recorded in 3/182 HILPs (1.6%) of the G-B and G-C groups.

CONCLUSION

These data suggested that the technical implementations reduced the occurrence and the severity of the side effects and complications. The essential requirement for HILP is the quality assurance of the procedures. Although higher regional and systemic toxicity were observed in the G-C group caused by L-PAM additional bolus, the safeness of the procedures under the true hyperthermal regimen and the time increase of the high L-PAM concentration have assured the treatment reliability along with the increased clinical efficacy expectations of the treatments.

Hyperthermia and hypoxia: new developments in anticancer chemotherapy

It has been demonstrated in vitro and in vivo that hyperthermia can enhance the cytotoxicity of some chemotherapeutic agents. The in vivo studies have demonstrated that the thermal advantage is maximized at mild temperatures such as at 40.5--43 degrees C. Thermo-chemotherapy is widely applied in limb perfusion and intraperitoneal chemotherapy. Hypoxia in solid tumours leads to resistance to most anticancer drugs and appears to accelerate malignant progression and increase metastasis. The recent development of new drugs highly toxic to hypoxic cells may bring new strategies in anticancer treatments and move this condition from being a problem to a new tool in cancer control.

Effect of melphalan and hyperthermia on cell cycle progression and cyclin B1 expression in human melanoma cells

We have investigated the effect of mild hyperthermia (42 degrees C) on the cytotoxic activity of a 1 h melphalan exposure in human melanoma cell lines. Hyperthermia did not affect cell growth of any culture, but it increased, to a different extent, melphalan cytotoxicity in all cell lines, with a reduction in the IC50 of 1.7 to 2.6-fold. Flow cytometric analysis showed that in normal temperature conditions melphalan caused S phase cell accumulation, which was evident only at 24 h in JR8, M14 and 2/21 cell lines and was still persistent at 72 h in 2/60 cells. Moreover, in all cell lines, the delay in S phase was paralleled, or followed, by an accumulation of cells in G2+M, which was transient in JR8 and M14 cells and persisted until 72 h in 2/21 and 2/60 melanoma clones. Hyperthermia caused a stabilization and prolongation of melphalan induced G2+M accumulation in JR8 and M14 cells. Conversely, in 2/21 and 2/60 clones, cell cycle perturbations induced by the drug were similar under normothermic or hyperthermic conditions. Specifically, in JR8, for which the maximum enhancement by hyperthermia on melphalan cytotoxicity was observed, cell accumulation in G2+M was still present 120 h after treatment. The accumulation was accompanied by an inhibition in the G2-M transition, as demonstrated by the significant reduction in the mitotic index of cells exposed to combined treatment compared to controls. Moreover, a bivariate distribution of cells stained for DNA and cyclin B1 showed that, following melphalan and hyperthermia treatment, the fraction of cyclin B1-expressing cells paralleled the fraction of G2+M phase cells, thus indicating that the inability of cells to enter mitosis was not ascribable to a reduction of cyclin B1 expression. On the whole, our results indicate that hyperthermia can stabilize the G2 accumulation induced by melphalan in human melanoma cells. Such a stabilization could contribute to the enhancement of melphalan cytotoxicity by heat, even though a strict correlation was not observed between the magnitude and persistence of the cell cycle perturbations and the extent of melphalan activity.

Effect of hyperthermia on the formation and removal of DNA interstrand cross-links induced by melphalan in primary cultures of human malignant melanoma

In an attempt to elucidate possible mechanisms responsible for the synergistic interaction between hyperthermia and melphalan observed in melanoma cells, we investigated the effect of heat on the formation and removal of melphalan-induced DNA interstrand cross-links (DNA ISC). Cells obtained from melanoma nodal metastases of 15 patients were grown as monolayer primary cultures and their malignant nature was confirmed by specific monoclonal antibodies. Cultures were treated with melphalan for 1 h at 37 or 42 degrees C and DNA ISC were determined by alkaline elution after proteinase K digestion. Results showed an enhanced induction of DNA ISC at hyperthermic conditions. Median number of DNA lesions 6 h after treatment was significantly higher for samples treated at 42 degrees C than for those treated at 37 degrees C (185 compared with 95 rad equivalents, p = 0.01). Moreover, the concomitant hyperthermic treatment prevented the long-term removal of DNA ISC produced by melphalan in most of the tumours considered.