[Treatment of otherwise incurable tumor diseases in childhood using whole-body hyperthermia and chemotherapy]

Controllable assembly of dendritic DNA nanostructures for ultrasensitive detection of METTL3-METTL14 m6A methyltransferase activity in cancer cells and human breast tissues

N⁶-Methyladenosine (m⁶A) is a reversible chemical modification in eukaryotic messenger RNAs and long noncoding RNAs. The aberrant expression of RNA methyltransferase METTL3-METTL14 complex may change the m⁶A methylation level and cause multiple diseases including cancers. The conventional METTL3-METTL14 assays commonly suffer from time-consuming procedures and poor sensitivity. Herein, we develop a controllable amplification machinery based on MazF-activated terminal deoxynucleotidyl transferase (TdT)-assisted dendritic DNA structure assembly for ultrasensitive detection of METTL3-METTL14 complex activity in cancer cells and breast tissues. The presence of METTL3-METTL14 complex catalyzes the formation of m⁶A in detection probe, effectively preventing the cleavage of methylated detection probes by MazF. The methylated detection probes with 3'-OH termini can function as the primers for template-free polymerization catalyzed by TdT on magnetic beads (MBs), producing long chains of poly-thymidine (poly-T) sequences. Then poly-T sequences hybridize with signal probes that contain poly-adenine (poly-A) sequence, inducing TdT-mediated polymerization and the subsequent hybridization with more poly-A signal probes for generating dendritic DNA nanostructures assembled on MBs. After magnetic separation and elevated temperature treatment, the signal probes are disassembled from MBs to generate a high fluorescence signal. This method possesses excellent specificity and high sensitivity with a limit of detection (LOD) of 2.61 × 10^-15 M, and it can accurately quantify cellular METTL3-METTL14 complex at single-cell level. Furthermore, it can screen inhibitors, evaluate kinetic parameters, and discriminate breast cancer tissues from normal tissues.

Re‑irradiation plus hyperthermia for recurrent pediatric sarcoma; a simulation study to investigate feasibility

Recurrent pediatric tumors pose a challenge since treatment options may be limited, particularly after previous irradiation. Positive results have been reported for chemotherapy and hyperthermia, but the combination of re‑irradiation and hyperthermia has not been investigated thus far, although it is a proven treatment strategy in adults. The theoretical feasibility of re‑irradiation plus hyperthermia was investigated for infield recurrent pediatric sarcoma in the pelvic region and the extremities. A total of 46 recurrent pediatric sarcoma cases diagnosed at the Academic Medical Center (Amsterdam, The Netherlands) between 2002 and 2017 were evaluated. Patients not previously irradiated, outfield recurrences and locations other than the pelvis and extremities were excluded, ultimately yielding four eligible patients: Two with sarcomas in the pelvis and two in an extremity. Re‑irradiation and hyperthermia treatment plans were simulated for 23x2 Gy treatment schedules and weekly hyperthermia. The radiosensitizing effect of hyperthermia was quantified using biological modelling with a temperature‑dependent change in the parameters of the linear‑quadratic model. The possible effectiveness of re‑irradiation plus hyperthermia was estimated by calculating the equivalent radiotherapy dose distribution. Treatment planning revealed that tumors located in the pelvis and the extremities can be effectively heated in children. Equivalent dose distributions indicated that hyperthermic radiosensitization can be quantified as a target‑selective additional D95% of typically 10 Gy, thereby delivering a possibly curative dose of 54 Gy, without substantially increasing the equivalent dose to the organs at risk. Therefore, re‑irradiation plus hyperthermia is a theoretically feasible and possibly effective treatment option for recurrent pediatric sarcoma in the pelvic region and the extremities, and its clinical feasibility is worthy of evaluation.

Regional hyperthermia combined with chemotherapy in paediatric, adolescent and young adult patients: current and future perspectives

Here we evaluate the current status of clinical research on regional hyperthermia (RHT) in combination with chemotherapy or radiation therapy in paediatric oncology.Data were identified in searches of MEDLINE, Current Contents, PubMed, and references from relevant articles using medical subject headings including hyperthermia, cancer, paediatric oncology, children, radiation therapy and chemotherapy. Currently, only two RHT centres exist in Europe which treat children. Clinical RHT research in paediatric oncology has as yet been limited to children with sarcomas and germ cell tumours that respond poorly to or recur after chemotherapy. RHT is a safe and effective treatment delivering local thermic effects, which may also stimulate immunological processes via heat-shock protein reactions. RHT is used chiefly in children and adolescents with sarcomas or germ cell tumours located in the abdomino-pelvic region, chest wall or extremities to improve operability or render the tumour operable. It could potentially be combined with radiation therapy in a post-operative R1 setting where more radical surgery is not possible or combined with chemotherapy instead of radiation therapy in cases where the necessary radiation dose is impossible to achieve or would have mutilating consequences. RHT might also be an option for chemotherapy intensification in the neoadjuvant first-line treatment setting for children and adolescents, as was recently reflected in the promising long-term outcome data in adults with high-risk soft tissue sarcomas (EORTC 62961/ESHO trial).The limited data available indicate that combining RHT with chemotherapy is a promising option to treat germ cell tumours and, potentially, sarcomas. RHT may also be beneficial in first-line therapy in children, adolescents and young adults. The research should focus on optimising necessary technical demands and then initiate several clinical trials incorporating RHT into interdisciplinary treatment of children, adolescents and young adults that include translational research components exploring potential immunological mechanisms of action.

Protocol for long duration whole body hyperthermia in mice

Hyperthermia is a general term used to define the increase in core body temperature above normal. It is often used to describe the increased core body temperature that is observed during fever. The use of hyperthermia as an adjuvant has emerged as a promising procedure for tumor regression in the field of cancer biology. For this purpose, the most important requirement is to have reliable and uniform heating protocols. We have developed a protocol for hyperthermia (whole body) in mice. In this protocol, animals are exposed to cycles of hyperthermia for 90 min followed by a rest period of 15 min. During this period mice have easy access to food and water. High body temperature spikes in the mice during first few hyperthermia exposure cycles are prevented by immobilizing the animal. Additionally, normal saline is administered in first few cycles to minimize the effects of dehydration. This protocol can simulate fever like conditions in mice up to 12-24 hr. We have used 8-12 weeks old BALB/Cj female mice to demonstrate the protocol.

Current devices for high-performance whole-body hyperthermia therapy

For late-stage cancer, whole-body hyperthermia (WBH) is highly regarded by physicians as a promising alternative to conventional therapies. Although WBH is still under scrutiny due to potential toxicity, its benefits are incomparable, as diversified devices and very promising treatment protocols in this area are advanced into Phase II and III clinical trials. Following the introduction of the WBH principle, this paper comprehensively reviews the state-of-art high-performance WBH devices based on the heat induction mechanisms - radiation, convection and conduction. Through analyzing each category's physical principle and heat-induction property, the advantages and disadvantages of the devices are evaluated. Technical strategies and critical scientific issues are summarized. For future developments, research directions worth pursuing are presented in this article.

Whole body hyperthermia in adjuvant therapy of children with renal cell carcinoma

Whole body hyperthermia (WBH) in combination with chemotherapy has been proven to be effective in some patients with advanced malignancies. However, only limited experience exists regarding the application of WBH with chemotherapy in children. We present the results of applying WBH and chemotherapy in five children with advanced renal cell carcinoma (RCC). WBH (3 hr, 41.8-42.5 degrees C) combined with doxorubicin (50 mg/m2) and interferon-alpha (3 MU/m2) were applied to patients after nephrectomy and lymph node dissection. Each patient received three to eight courses of treatment three times weekly. All children tolerated the combined therapy well without complications. Follow-up of 7-68 months (median: 22 months) showed no tumor progression in patients with locoregional (n = 3) and metastatic (n = 2) disease. WBH with moderate dose doxorubicin and INF-alpha might be a feasible treatment option in childhood RCC.

Estimated number of children with cancer eligible for hyperthermia based on population- and treatment-related criteria

Patients with recurrent, progressed or otherwise, therapy resistant malignancies, whose diseases are not amenable to standard therapies, may benefit from hyperthermia (HT). Based on the number of 1600 newly diagnosed malignancies, in patients < 15 years of age, per annum of which 70% are successfully treated on the standard treatment protocols of the German Society of Pediatric Oncology and Hematology (GPOH) and allowing for various drop-outs for reasons such as lack of established protocols, insufficient state of health and others, this means that as many as 100 children per annum can be expected to be enrolled into phase I/II trials in Germany. In view of the promising results in adults, phase I/II HT studies have also been performed in children and adolescents with recurrent or advanced malignancies including Ewing's tumours, aggressive fibromatosis, and germ cell tumours. Recent results in paediatric studies indicate the feasibility of both regional deep HT and whole body HT, and the best case analysis reveals promising response rates (CR + PR) as well as some long-term remissions. Technical modifications, due to the smaller body diameters, led to mean intratumoural temperatures in paediatric patients similar to those reported for adults in whom an improved outcome was demonstrated. The results in children and adolescents even suggest that introduction of HT into standard treatment protocols may be promising to improve tumour response and event-free survival in patients with poor risk malignancies of childhood.

Total body hyperthermia in combination with etoposide and melphalan in a child with acute myelomonocytic leukemia

In vitro and clinical studies have shown antineoplastic effects of hyperthermia alone and in combination with other treatment modalities. Synergistic cytotoxic effects of chemotherapy and hyperthermia have been demonstrated on leukemic cell clones in vitro. It seems that hyperthermia is effective in overcoming chemotherapy resistance. Several groups treated solid tumors by using total body hyperthermia (TBHT). However, only a few studies have been reported investigating the clinical effects of TBHT in myeloproliferative disorders. We report the case of a 7-year-old boy with myelomonocytic leukemia treated with TBHT (2 hours, 42 degrees C) combined with etoposide (600 mg/m2), melphalan (30 mg/m2) and hyperglycemia (200-300 mg/dl). Within 24 hours after TBHT, the leukemic cells decreased after TBHT from 53,000/microliters to zero. Skin leukemic infiltrates, resistant to conventional treatment, also responded well. Although our patient relapsed 34 days after TBHT, these results indicate that TBHT in combination with cytotoxic treatment may be a useful treatment modality in refractory leukemia.

Effect of glucose-mediated pH reduction and cyclophosphamide on oxygenation of transplanted rat tumors

PURPOSE

Glucose-mediated reduction of tumor pH is under investigation as a means to improve the therapeutic index of anticancer agents. An improvement of glucose supply to tumors is, however, likely to influence various metabolic and pathophysiological parameters apart from pH which, in turn, could modulate H+ ion-mediated effects. As a first step to identify changes in these parameter, we have investigated the effect of glucose-mediated pH reduction on oxygenation of malignant tissues either per se or in combination with a pH-sensitive drug, cyclophosphamide.

METHODS AND MATERIALS

H+ ion and oxygen-sensitive semi-microelectrodes were used to measure pH and pO2 in transplanted TV1A and AH13r rat tumors at normoglycemia and following high-dose intravenous glucose infusion.

RESULTS

In both tumors analyzed, pH reduction was accompanied by a decrease in pO2. In TV1A tumors, for example, the mean (median) pO2 decreased from 8.2 mm Hg (3.7 mm Hg) to 3.9 mm Hg (1.7 mm Hg) at 2 hr and 2.9 mm Hg (1.9 mm Hg) at 24 hr, respectively, after raising the plasma glucose concentration to 25 +/- 2 mmol/l. At the same time points, the mean pH had declined from 6.89 to 6.29 and 6.24, respectively. The class of pO2 readings < 5 mm Hg increased from a pretreatment value of 65% to approximately 90% at 24 hr. In contrast, cyclophosphamide treatment resulted in improved oxygenation of AH13r tumors, an effect first observed at 24 hr after drug administration. When both modalities were combined, cyclophosphamide partly prevented the acidosis-associated decrease in oxygen partial pressure.

CONCLUSION

The results of this study indicate that, within the context of the therapeutic approach used, cytotoxic agents should be employed which are more active against hypoxic than against well-oxygenated cells. In particular, glucose-mediated reduction of oxygen partial pressure in malignant tissues may be exploited to increase the fraction of hypoxic cells prior to administration of drugs activated in hypoxic cells by reductive metabolism (bioreductive agents).