In Vitro Examinations of Cell Death Induction and the Immune Phenotype of Cancer Cells Following Radiative-Based Hyperthermia with 915 MHz in Combination with Radiotherapy

Advances in Ferroptosis-Inducing Agents by Targeted Delivery System in Cancer Therapy

Currently, cancer remains one of the most significant threats to human health. Treatment of most cancers remains challenging, despite the implementation of diverse therapies in clinical practice. In recent years, research on the mechanism of ferroptosis has presented novel perspectives for cancer treatment. Ferroptosis is a regulated cell death process caused by lipid peroxidation of membrane unsaturated fatty acids catalyzed by iron ions. The rapid development of bio-nanotechnology has generated considerable interest in exploiting iron-induced cell death as a new therapeutic target against cancer. This article provides a comprehensive overview of recent advancements at the intersection of iron-induced cell death and bionanotechnology. In this respect, the mechanism of iron-induced cell death and its relation to cancer are summarized. Furthermore, the feasibility of a nano-drug delivery system based on iron-induced cell death for cancer treatment is introduced and analyzed. Secondly, strategies for inducing iron-induced cell death using nanodrug delivery technology are discussed, including promoting Fenton reactions, inhibiting glutathione peroxidase 4, reducing low glutathione levels, and inhibiting system Xc-. Additionally, the article explores the potential of combined treatment strategies involving iron-induced cell death and bionanotechnology. Finally, the application prospects and challenges of iron-induced nanoagents for cancer treatment are discussed.

A Novel Oncogenic Role of Disulfidptosis-related Gene SLC7A11 in Anti-tumor Immunotherapy Response to Human Cancers

BACKGROUND

The protein Solute Carrier Family 7 Member 11 (SLC7A11) plays a pivotal role in cellular redox homeostasis by suppressing disulfidptosis, which restricts tumor growth. Yet, its relevance in prognosis, immunity, and cancer treatment efficacy is not well understood.

METHODS

We conducted a comprehensive analysis of the expression of SLC7A11 across 33 cancer types, employing datasets from public databases. Methods, such as Cox regression and survival analyses assessed its prognostic significance, while functional enrichment explored the biological processes tied to SLC7A11. The association between SLC7A11 expression, immune cell infiltration, and immune-related gene expression was also scrutinized.

RESULTS

Notably, SLC7A11 expression was more pronounced in cancerous compared to normal samples and correlated with higher tumor grades. Increased SLC7A11 expression was linked to poor outcomes, particularly in liver hepatocellular carcinoma (LIHC). This protein's expression also showcased significant relationships with diverse molecular and immune subtypes. Additionally, a prognostic nomogram was devised, integrating SLC7A11 expression and clinical variables. High SLC7A11 levels corresponded with cell growth and senescence pathways in various cancers and with lipid and cholesterol metabolism in LIHC. Furthermore, potential therapeutic compounds for LIHC with high SLC7A11 were identified. Real-time PCR (qPCR) and Western blot were conducted to explore the expression of SLC7A11 in tumor tissues and cancer cell lines.

CONCLUSION

In summation, this study emphasizes the prognostic and immunological importance of SLC7A11, spotlighting its potential as a therapeutic target in LIHC.

Broadband microwave spiral applicator (105-125 MHz) for in vitro examinations of hyperthermia-induced tumor cell death forms - first analyses with human breast cancer cells

PURPOSE

Local tumor heating with microwave applicators has been used in multimodal breast cancer therapies. This hyperthermia allows to target small regions while marginally affecting healthy tissue. However, most preclinical examinations only use simplified heating methods. Microwave applicators employed for deep heating to provide the greatest depth of penetration operate in the tens to hundreds frequency. Therefore, we aimed to adapt and test a clinically often used broadband spiral applicator (105-125 MHz) for hyperthermia with clinically wanted temperatures of 41 and 44 °C in in vitro settings with human breast cancer cell lines and with simulations.

MATERIAL AND METHODS

A clinically used spiral-microwave applicator (105-125 MHz) was the basis for the construction, simulation, and optimization of the in vitro HT set-up under stationary conditions. Microwave effects on tumor cell death of two human breast cancer cell lines (hormone-receptor positive MCF-7 and triple-negative MDA-MB-231) were compared with conventional heating in a contact-heating chamber. Cell death forms were analyzed by AnnexinV/Propidium iodide staining.

RESULTS

An in vitro spiral applicator microwave-based heating system that is effective at applying heat directly to adherent breast cancer cells in cell culture flasks with medium was developed. Simulations with COMSOL proved appropriate heat delivery and an optimal energy coupling at a frequency of 111 ± 2.5 MHz. Apoptosis and necrosis induction and significantly higher cell death rates than conventional heating at both temperatures were observed, and MCF-7 showed higher death rates than MDA-MB-231 tumor cells.

CONCLUSIONS

Well-characterized in vitro heating systems are mandatory for a better understanding of the biological effects of hyperthermia in tumor therapies and to finally determine optimized clinical treatment schemes.

Combination Therapy of Radiation and Hyperthermia, Focusing on the Synergistic Anti-Cancer Effects and Research Trends

Despite significant therapeutic advances, the toxicity of conventional therapies remains a major obstacle to their application. Radiation therapy (RT) is an important component of cancer treatment. Therapeutic hyperthermia (HT) can be defined as the local heating of a tumor to 40-44 °C. Both RT and HT have the advantage of being able to induce and regulate oxidative stress. Here, we discuss the effects and mechanisms of RT and HT based on experimental research investigations and summarize the results by separating them into three phases. Phase (1): RT + HT is effective and does not provide clear mechanisms; phase (2): RT + HT induces apoptosis via oxygenation, DNA damage, and cell cycle arrest; phase (3): RT + HT improves immunological responses and activates immune cells. Overall, RT + HT is an effective cancer modality complementary to conventional therapy and stimulates the immune response, which has the potential to improve cancer treatments, including immunotherapy, in the future.

The Emerging Evidence Supporting Integration of Deep Regional Hyperthermia With Chemoradiation in Bladder Cancer

For decades, the antineoplastic potential of hyperthermia alone or in combination with radiotherapy and/or chemotherapy has been subject of intensive preclinical and clinical research in various tumor entities. The clinical evidence on the beneficial effects of additional hyperthermia in combination with intravesical Mitomycin C for superficial non-muscle-invasive bladder cancer as well as for deep regional microwave hyperthermia techniques applied during an external beam radiotherapy or chemoradiation treatment for more advanced tumors are summarized. In some series, deep regional hyperthermia in combination with an initial transurethral resection and Cisplatin-based chemoradiation increased the 5-year overall survival rates up to 20%. The presented data justifies a fresh irrespective chance for mild regional hyperthermia in the context of new progressive prospective trials on multimodality treatment for bladder preservation.

Exosomal microRNA-506 inhibits biological activity of lung adenocarcinoma cells and increases sensitivity to cisplatin-based hyperthermia

Exosomal microRNAs (miRNAs) play a vital role in the occurrence and development of lung adenocarcinoma (LUAD). Based on the bioinformatics analyses, the current study sought to explore the effects of exosomal miR-506 on LUAD cell biology and the efficacy of cisplatin (CDDP)-based hyperthermia (HT). After sample preparation, we identified decreased miR-506 and elevated ATAD2. LUAD cells were subsequently transfected with miR-506 mimic, oe-ATAD2 and PI3K/AKT signaling pathway inhibitor LY294002 to analyze effects of the miR-506/ATAD2/PI3K/AKT axis on cell biological processes and chemoresistance. Effects of exosomal miR-506 on sensitivity of LUAD cells to CDDP-based HT were further assessed in a co-culture system of BMSC-derived exosomes and LUAD cells, which was also validated in tumor-bearing nude mice. miR-506 down-regulated ATAD2 to inhibit the PI3K/AKT signaling pathway, thereby inhibiting the malignant phenotypes of LUAD cells and augmenting LUAD cell sensitivity to CDDP-based HT. Further, BMSCs-derived exosomes harboring miR-506 sensitized LUAD cells to DDP/HT both in vitro and in vivo. Collectively, our findings revealed that exosomal miR-506 sensitized LUAD cells to CDDP-based HT by inhibiting ATAD2/PI3K/AKT signaling pathway, offering a potential therapeutic target for LUAD treatment.

Radiotherapy and hyperthermia for breast cancer patients at high risk of recurrence

PURPOSE

To evaluate the long-term efficacy of combined radiotherapy (RT) and hyperthermia (HT) in a large mono-institutional cohort of breast cancer (BC) patients affected by recurrent, newly diagnosed non-resectable or high risk resected tumor.

MATERIALS AND METHODS

Records of BC patients treated with RT + HT between 1995 and 2018 were retrospectively analyzed. RT doses of 50-70 Gy concurrent to a twice per week superficial HT were applied. For HT, a temperature between 41 and 42 °C was applied for approximately 1 h. Primary endpoint was local control (LC), secondary endpoints comprised toxicity, overall survival (OS), and progression-free survival (PFS).

RESULTS

A total of 191 patients and 196 RT + HT treatments were analyzed. In 154 cases (78.6%) RT + HT was performed for patients with recurrent BC. Among these, 93 (47.4% of the entire cohort) had received RT prior to RT + HT. Median follow up was 12.7 years. LC at 2, 5, and 10 years was 76.4, 72.8, and 69.5%, respectively. OS at 2, 5, and 10 years was 73.5, 52.3, and 35.5%, respectively. PFS at 2, 5, and 10 years was 55.6, 41, and 33.6%, respectively. Predictive factors for LC were tumor stage, distant metastases, estrogen/progesterone receptor expression, resection status and number of HT fractions. At multivariate analysis tumor stage and receptor expression were significant. No acute or late toxicities higher than grade 3 were observed.

CONCLUSION

Combined RT + HT offers long-term high LC rates with acceptable toxicity for patients with recurrent, newly diagnosed non-resectable or resected BC at high risk of relapse.

Detailed in vitro analyses of the impact of multimodal cancer therapy with hyperthermia and radiotherapy on the immune phenotype of human glioblastoma cells

PURPOSE

Improvements of heat-delivery systems have led to hyperthermia (HT) being increasingly recognized as an adjunct treatment modality also for brain tumors. But how HT affects the immune phenotype of glioblastoma cells is only scarcely known.

MATERIALS AND METHODS

We therefore investigated the effect of in vitro HT, radiotherapy (RT), and the combination of both (RHT) on cell death modalities, immune checkpoint molecule (ICM) expression and release of the danger signal HSP70 of two human glioblastoma cell lines (U87 and U251) by using multicolor flow cytometry and ELISA. Hyperthermia was performed once or twice for 60-minute sessions reaching temperatures of 39 °C, 41 °C, and 44 °C, respectively. RT was administered with 5 x 2 Gy.

RESULTS

A hyperthermia chamber for cell culture t-flasks regulating the temperature via a contact sensor was developed. While the glioblastoma cells were rather radioresistant, particularly in U251 cells, the combination of RT with HT significantly increased the percentage of apoptotic and necrotic cells for all temperatures examined and for both, single and double HT application. In line with that, an increased release of HSP 70 was seen only in U251 cells, mainly following treatment with HT at temperatures of 44 °C alone or in combination with RT. In contrast, immune suppressive (PD-L1, PD-L2, HVEM) and immune stimulatory (ICOS-L, CD137-L and Ox40-L) ICMs were significantly increased mostly on U87 cells, and particularly after RHT with 41 °C.

CONCLUSIONS

Individual assessment of the glioblastoma immune cell phenotype with regard to the planned treatment is mandatory to optimize multimodal radio-immunotherapy protocols including HT.