From laboratory studies to clinical trials: past benefits and future directions in hyperthermia

Integrating single-cell sequencing data with GWAS summary statistics reveals CD16+monocytes and memory CD8+T cells involved in severe COVID-19

Background

Understanding the host genetic architecture and viral immunity contributes to the development of effective vaccines and therapeutics for controlling the COVID-19 pandemic. Alterations of immune responses in peripheral blood mononuclear cells play a crucial role in the detrimental progression of COVID-19. However, the effects of host genetic factors on immune responses for severe COVID-19 remain largely unknown.

Methods

We constructed a computational framework to characterize the host genetics that influence immune cell subpopulations for severe COVID-19 by integrating GWAS summary statistics (N = 969,689 samples) with four independent scRNA-seq datasets containing healthy controls and patients with mild, moderate, and severe symptom (N = 606,534 cells). We collected 10 predefined gene sets including inflammatory and cytokine genes to calculate cell state score for evaluating the immunological features of individual immune cells.

Results

We found that 34 risk genes were significantly associated with severe COVID-19, and the number of highly expressed genes increased with the severity of COVID-19. Three cell subtypes that are CD16+monocytes, megakaryocytes, and memory CD8+T cells were significantly enriched by COVID-19-related genetic association signals. Notably, three causal risk genes of CCR1, CXCR6, and ABO were highly expressed in these three cell types, respectively. CCR1⁺CD16+monocytes and ABO⁺ megakaryocytes with significantly up-regulated genes, including S100A12, S100A8, S100A9, and IFITM1, confer higher risk to the dysregulated immune response among severe patients. CXCR6⁺ memory CD8+ T cells exhibit a notable polyfunctionality including elevation of proliferation, migration, and chemotaxis. Moreover, we observed an increase in cell-cell interactions of both CCR1⁺ CD16+monocytes and CXCR6⁺ memory CD8+T cells in severe patients compared to normal controls among both PBMCs and lung tissues. The enhanced interactions of CXCR6⁺ memory CD8+T cells with epithelial cells facilitate the recruitment of this specific population of T cells to airways, promoting CD8+T cell-mediated immunity against COVID-19 infection.

Conclusions

We uncover a major genetics-modulated immunological shift between mild and severe infection, including an elevated expression of genetics-risk genes, increase in inflammatory cytokines, and of functional immune cell subsets aggravating disease severity, which provides novel insights into parsing the host genetic determinants that influence peripheral immune cells in severe COVID-19.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-022-01021-1.

Transferrin as a thermosensitizer in radiofrequency hyperthermia for cancer treatment

One of the main characteristics of cancer tissues is poor development of neovascularization that results in a limited blood circulation. Because of this phenomenon, it is harder for cancer tissues to diffuse their elevated heat into other parts of the body. The scientific principle of radiofrequency hyperthermia relies on this quality of cancer tissues which with higher temperature becomes more apparent. Despite the obvious necessity to selectively heat the cancer tissue for radiofrequency hyperthermia, a proper thermosensitizer has not been developed until now. Here, we show that transferrin containing ferric ion could be an ideal thermosensitizer for the increased efficiency of radiofrequency hyperthermia. In our result, the ferric ion-enriched cancer tissues dramatically react with 13.56 MHz radiofrequency wave to cause cancer-selective dielectric temperature increment. The overall anticancer efficacy of a 13.56 MHz radiofrequency hyperthermia using transferrin as a thermosensitizer was much higher than the oncotherapeutic efficacy of paclitaxel, successfully eradicating cancer in a tumor-xenografted mouse experiment.

The role of oxygen in cutaneous photodynamic therapy

Photodynamic therapy (PDT) is based on the dye-sensitized photooxidation of biological matter in the target tissue, and utilizes light activated drugs for the treatment of a wide variety of malignancies. Skin is a target organ for PDT, because of the increasing incidence of skin cancers and the easy accessibility to photosensitizing drugs and light. Skin oxygen tension changes dramatically during and after PDT and seems to be an important treatment parameter. Experimental approaches to modulate oxygen tension (e.g., hyperbaric oxygenation, hyperthermia, or perfluorocarbons) have been studied mainly in animals, and some of these techniques may have the potential to be applied in humans to improve the efficacy and safety of PDT. The main purpose of this review is to provide the reader with current information on cutaneous oxygen physiology and oximetry, the role of oxygen and singlet oxygen (1O2) in PDT, and approaches to modulate skin oxygen tension. The literature indicates that it may be possible to utilize transcutaneous oxygen measurements as a valuable measure of the clinical effectiveness of PDT and as an in situ predictor of the energy required to elicit a biological response. Consequently the effectiveness of PDT can be manipulated by modulating skin oxygen tension.

Interstitial radiation and hyperthermia in the Dunning R3327 prostate tumour model: therapeutic efficacy depends on radiation dose-rate, sequence and frequency of heating

To determine the most effective means by which to apply the combined treatments of local tumour hyperthermia (LTH) with interstitial low dose-rate irradiation (IRT) we examined the significance of such factors as dose-rate of radiation, and the sequence and frequency of hyperthermia applications in the anaplastic Dunning prostate tumour subline R3327-AT1. IRT was carried out by the insertion of a single Ir-192 seed into the center of the tumour. For LTH treatments, the tumour-bearing leg was positioned in a circulating constant temperature water bath (43.5 +/- 0.1 degrees C) for 35 min. Neither LTH treatment alone nor the insertion of a dummy seed produced any change in tumour growth compared with sham-treated controls. With regard to the sequence of heating and IRT our results showed that during a 72-h treatment time (30 Gy, 40 cGy/h) a single heat treatment given just before the start of IRT was more efficient (TER = 1.47) in terms of growth delay than LTH given in the middle or the end of radiation treatment (TER approximately 1.0). The growth delay for both the 20 and 40 cGy/h groups appear to be linear with increasing dose for the IRT as well as the IRT + LTH groups. The higher dose-rate was more effective especially with respect to long-term delay in tumour growth in some of the animals. As TER at 40 cGy/h decreased subsequently with increasing treatment time from 1.47 to 1.25 at 60 Gy, we conclude that for treatment times > 72 h, one LTH just before IRT might not be sufficient. If multiple heat treatments are applied during a comparable time course, two LTH treatments one just before the start, the other at the end yielded the greatest local tumour control. In contrast, three LTH given daily were not more effective than the one LTH given just before the start of IRT. These data indicate a clear thermal enhancement of low dose-rate irradiation, with maximal sensitization when hyperthermia was given just before IRT. For multiple heatings a better understanding of the underlying mechanisms of sequencing and timing hopefully provides guidelines how to apply optimally both modalities in the treatment of cancer.