Hyperthermia in the multimodal therapy of advanced rectal carcinomas

Continuous mild heat stress induces differentiation of mammalian myoblasts, shifting fiber type from fast to slow

Local hyperthermia has been widely used as physical therapy for a number of diseases such as inflammatory osteoarticular disorders, tendinitis, and muscle injury. Local hyperthermia is clinically applied to improve blood and lymphatic flow to decrease swelling of tissues (e.g., skeletal muscle). As for muscle repair following injury, the mechanisms underlying the beneficial effects of hyperthermia-induced muscle repair are unknown. In this study, we investigated the direct effects of continuous heat stress on the differentiation of cultured mammalian myoblasts. Compared with control cultures grown at 37 degrees C, incubation at 39 degrees C (continuous mild heat stress; CMHS) enhanced myotube diameter, whereas myotubes were poorly formed at 41 degrees C by primary human skeletal muscle culture cells, human skeletal muscle myoblasts (HSMMs), and C2C12 mouse myoblasts. In HSMMs and C2C12 cells exposed to CMHS, mRNA and protein levels of myosin heavy chain (MyHC) type I were increased compared with the control cultures. The mRNA level of MyHC IIx was unaltered in HSMMs and decreased in C2C12 cells, compared with cells that were not exposed to heat stress. These results indicated a fast-to-slow fiber-type shift in myoblasts. We also examined upstream signals that might be responsible for the fast-to-slow shift of fiber types. CMHS enhanced the mRNA and protein levels of peroxisome proliferator-activated receptor-gamma coactivator (PGC)-1alpha in HSMMS and C2C12 cells but not the activities of MAPKs (ERK1/2 and p38 MAPK) in HSMMs and C2C12 cells. These data suggest that CMHS induces a fast-to-slow fiber-type shift of mammalian myoblasts through PGC-1alpha.

Hyperthermia for rectal cancer

BACKGROUND

In order to improve the clinical results of rectal cancer, hyperthermia has been prescribed in combination with chemotherapy and radiotherapy. The techniques of hyperthermia and their clinical applications to rectal cancer were reviewed.

METHODS

The development of heating devices has been intensively investigated, including external heating devices, intraluminal heating devices, circulation of warmed saline solution, and whole body hyperthermia.

RESULTS

Nonrandomized and randomized trials for rectal cancer have demonstrated an improved local response with the combined use of hyperthermia and conventional treatments. A preoperative therapy with hyperthermia increased resectability and decreased local recurrence, resulting in the improvement of the postoperative prognosis. There were no major postoperative complications related to the preoperative treatment. A lower incidence of local recurrence was observed in groups that underwent intra- or postoperative hyperthermia treatment, as compared with control groups. In cases with unresectable or local recurrent rectal cancer, hyperthermia achieved a local tumor regression and prolonged pain relief.

CONCLUSIONS

These clinical data suggest that hyperthermia combined with radiation or chemotherapy demonstrates great promise for the treatment of patients with carcinoma of the rectum.

Chemoprotection from p53-dependent apoptosis: potential clinical applications of the p53 inhibitors

The p53 tumor suppressor pathway is a key mediator of stress response that protects the organism from accumulating genetically altered and potentially cancerous cells by inducing growth arrest or apoptosis in damaged cells. However, under certain stressful conditions, p53 activity can result in massive apoptosis in sensitive tissues, leading to severe pathological consequences for the organism. One such situation is anticancer therapy that is often associated with general genotoxic stress, leading to p53-dependent apoptosis in the epithelia of the digestive tract and in the hematopoietic system. A chemical inhibitor of p53, capable of suppressing p53-mediated apoptosis, was shown to protect mice from lethal doses of gamma-radiation, making pharmacological suppression of p53 a perspective therapeutic approach to reduce the side-effects of cancer treatment. There are other situations, besides anti-cancer therapy, when humans are exposed to stressful conditions known to involve p53 activation, which, in extreme cases, could result in the development of life-threatening diseases. Here we review the experimental evidence on the role of p53 in tissue injuries associated with hypoxia (heart and brain ischemias) and hyperthermia (fever and burns), comparing these pathologies with the consequences of genotoxic stress of cancer treatment. The accumulated information points to the involvement of p53 in the generation of the pathological outcome of the above stresses, making them potential targets for the therapeutic application of p53 inhibitors.

A randomized clinical trial of radiation therapy versus thermoradiotherapy in stage IIIB cervical carcinoma

To clarify the role of thermoradiotherapy for FIGO Stage IIIB cervical carcinomas, both the clinical response and survival of patients treated with radio- or thermoradiotherapy were investigated. Forty patients with Stage IIIB uterine cervix carcinoma were treated with external beam irradiation to the pelvis, combined with iridium 192 high-dose-rate intracavitary brachytherapy. All patients were divided randomly into the following two groups: the radiotherapy (RT) group of 20 patients, who underwent radiotherapy alone; and the thermoradiotherapy (TRT) group of 20 patients, who underwent three sessions of hyperthermia in addition to radiotherapy. The primary endpoint of this study was local complete response and survival. A complete response was achieved in 50% (10 of 20) in the RT group versus 80% (16 of 20) in the TRT group (p = 0.048). The 3-year overall survival and disease-free survival of the patients who were treated with TRT (58.2 and 63.6%) were better than those of the patients treated with RT (48.1 and 45%), but these differences were not significant. The 3-year local relapse-free survival of the patients who were treated with TRT (79.7%) was significantly better than that of the patients treated with RT (48.5%) (p = 0.048). TRT, as delivered in this trial, was well tolerated and did not significantly add to either the relevant clinical acute or long-term toxicity over radiation alone. TRT resulted in a better treatment response and 3-year local relapse-free survival rate than RT for patients with FIGO Stage IIIB cervical carcinoma.

A pilot study of preoperative continuous infusion 5-fluorouracil, external microwave hyperthermia, and external beam radiotherapy for treatment of locally advanced, unresectable, or recurrent rectal cancer

PURPOSE

To determine the feasibility of combining external beam radiotherapy, continuous infusion 5-fluorouracil (5-FU), and external microwave hyperthermia in patients with locally advanced, unresectable, or recurrent adenocarcinoma of the rectum.

METHODS AND MATERIALS

From 7/95 through 2/99, 15 patients were enrolled in the study. The treatment regimen consisted of continuous infusion 5-FU 250 mg/m(2)/d 7 days/week beginning on day 1, external beam radiotherapy to the pelvis, 4500 cGy, 180 cGy/d 5 days/week using a 3 or 4-field technique, and external microwave hyperthermia on days 3, 8, 15, 22, and 29. Chemotherapy was stopped on the last day of radiotherapy. Surgical resection, if feasible, was scheduled 3-6 weeks after completing thermochemoradiotherapy. For this regimen to be considered feasible, no more than 2 of the 15 patients should fail to complete therapy due to life-threatening toxicity. Toxicity was scored using National Cancer Institute Criteria.

RESULTS

All patients completed the chemoradiotherapy portion of the protocol. Eleven of the 15 patients completed all 5 hyperthermia treatments. Of the 4 patients who did not receive the full course of hyperthermia, only 1 patient had treatment stopped due to life-threatening toxicity. The other 3 patients did not complete hyperthermia due to scheduling errors (n = 2) or patient request (n = 1). Five of 15 patients required a treatment interruption due to toxicity > or = Grade 3. Seven patients experienced lesser degrees of toxicity which did not require treatment interruption. Three patients experienced no side effects. The most common toxicities were dermatitis and diarrhea. Of the 14 patients in whom surgery was planned, 11 (79%) were resectable. There was one pathologic complete response.

CONCLUSIONS

It is feasible to deliver thermochemoradiotherapy, as prescribed in this study, to patients with locally advanced, unresectable, or recurrent rectal cancer. The therapy is moderately toxic, with one-third of patients requiring temporary treatment interruptions. The regimen appears active against rectal cancer, and appears to warrant further consideration as a treatment option for this patient population.

Combined modality therapy of rectal cancers

Rectal cancer accounts for about 10% of new cancer cases each year. It strikes men and women at nearly the same rate, generally in the range of 50-80 years of age, with rising incidence with age. Despite simple screening procedures rectal cancer is often advanced when discovered. Current trends in the management of cancer have focused on organ preservation and improved quality of life without compromising the overall survival. During the last decade substantial progress has been made in treatment modalities: new and improved radiation techniques (conformal radiotherapy, altered fractionation, brachytherapy), chemotherapy (protracted infusion, use of radiosensitizers) and development of surgical procedures-enabling safer postoperative irradiation. In patients with advanced/unresectable disease aggressive combined chemoradiation can be added prior to surgery to downstage the tumour and increase the proportion treated with anal-rectal-sparing procedures. Preoperative chemoradiation therapy regimens are as safe and tolerable as the standard postoperative treatment. In this presentation indications for preoperative radiochemotherapy will be discussed in detail, together with treatment-related side effects, prognostic parameters, tumour response and outcome. Different irradiation settings and chemotherapy schedules are described. In patients with primary resectable disease (mainly Dukes C) several prospective randomised trials have shown less local recurrence with postoperative combined modality therapy.

Search for novel proteins involved in the development of chemoresistance in colorectal cancer and fibrosarcoma cells in vitro using two-dimensional electrophoresis, mass spectrometry and microsequencing

In search of novel mechanisms that may lead to the development of chemoresistance of malignant tumors of the large bowel we used two-dimensional electrophoresis to identify proteins that were overexpressed in colorectal and fibrosarcoma cell lines that were resistant towards mitoxantrone. This cytostatic drug is known to lead to atypical multidrug resistance, i.e., the classical mechanism of multidrug resistance (MDR) accompanied by the overexpression of P-glycoprotein (P-gp) is ineffective. Using mass spectrometry and microsequencing we found adenine phosphoribosyl transferase and breast cancer specific gene 1 (BCSG1) overexpressed in the resistant colorectal tumor cell line. In the chemoresistant fibrosarcoma cell line we found two proteins that were overexpressed. One was identified as Rho-guanine dinucleotide phosphate (Rho-GDP) dissociation inhibitor and the other had sequence homologies with yeast protein yer-7. The putative role of these proteins is discussed.

Blood flow rate in normal and tumor-bearing rats in conscious state, under urethane anesthesia, and during systemic hypothermia

The blood flow rates of 14 tissues in the body were determined by microsphere method using normal and tumor-bearing rats kept conscious or under urethane anesthesia. The effects on the blood flow rate in the tissues were assessed for multimodal therapy, systemic hypothermia for ischemic brain injury, and local hyperthermia and angiotensin II-induced hypertensive chemotherapy for cancer. Urethane anesthesia showed no effect on cardiac output, while there was a tendency of decrease of blood flow rate and % of cardiac output in each tissue other than muscle tissue, in which they increased as a counterbalance, in normal and tumor-bearing rats. Systemic hypothermia gave results similar to those of urethane anesthesia in normal rats, but for tumor-bearing rats, it decreased cardiac output, and consequently the blood flow rate in most tissues. Brain blood flow rate was about half of that in the conscious rats. Local hyperthermia also decreased the cardiac output and blood flow rate in each tissue, including the tumor tissue. Angiotensin II-induced hypertension showed no effect on cardiac output, had various effects on blood flow rate in each tissue, and led to no increase in the tumor blood flow rate. Simulations based on the physiological pharmacokinetic modeling suggested that intramuscular injection of a lung-specific derivative of ceftazidime would provide the ideal biodistribution to ensure its optimal therapeutic efficacy during systemic hypothermia. This methodology, namely the pharmacokinetic simulation based on the physiological values of the body, will provide a useful piece of information on drug delivery systems under various conditions.