Effects of a Unique Combination of the Whole-Body Low Dose Radiotherapy with Inactivation of Two Immune Checkpoints and/or a Heat Shock Protein on the Transplantable Lung Cancer in Mice.

Non-small cell lung cancer (NSCLC) continues to be the leading cause of cancer death worldwide. Recently, targeting molecules whose functions are associated with tumorigenesis has become a game changing adjunct to standard anti-cancer therapy. As evidenced by the results of preclinical and clinical investigations, whole-body irradiations (WBI) with X-rays at less than 0.1-0.2 Gy per fraction can induce remissions of various neoplasms without inciting adverse side effects of conventional chemo- and radiotherapy. In the present study, a murine model of human NSCLC was employed to evaluate for the first time the anti-neoplastic efficacy of WBI combined with inactivation of CTLA-4, PD-1, and/or HSP90. The results indicate that WBI alone and in conjunction with the inhibition of the function of the cytotoxic T-lymphocyte antigen-4 (CTLA-4) and the programmed death-1 (PD-1) receptor immune checkpoints (ICs) and/or heat shock protein 90 (HSP90) markedly reduced tumorigenesis in mice implanted by three different routes with the syngeneic Lewis lung cancer cells and suppressed clonogenic potential of Lewis lung carcinoma (LLC1) cells in vitro. These results were associated with the relevant changes in the profile of pro- and anti-neoplastic immune cells recruited to the growing tumors and the circulating anti- and pro-inflammatory cytokines. In contrast, inhibition of the tested molecular targets used either separately or in combination with each other did not exert notable anti-neoplastic effects. Moreover, no significant synergistic effects were detected when the inhibitors were applied concurrently with WBI. The obtained results supplemented with further mechanistic explanations provided by future investigations will help design the effective strategies of treatment of lung and other cancers based on inactivation of the immune checkpoint and/or heat shock molecules combined with low-dose radiotherapy.

Time to rejuvenate ultra-low dose whole-body radiotherapy of cancer.

The results of clinical trials performed from the 1930s until the end of the 20th century in which total-body ultra-low level ionizing radiation (TB-LLR) was used demonstrate that this form of treatment can be equal or superior to other systemic anti-neoplastic modalities in terms of the rates of remissions, toxicity, and side effects. In this review, we provide the rationale for TB-LLR and analyze the results of reliable clinical trials in patients with predominantly lymphoproliferative disorders but also advanced solid cancers. The doses used in these trials did not exceed 0.1-0.2 Gy per fraction and cumulative totals ranged from 1 to 4 Gy. Based on the reviewed results we conclude that it is appropriate to revive interest in and resume clinical investigations of TB-LLR in order to refine and improve the effectiveness of such treatment, whether employed alone or in combination with other anticancer strategies.

Optimisation of [11C]-choline synthesis.

The importance of [11C]-choline as a PET/CT marker has been extensively described, although its production presents considerable technical difficulties. The main ones are short half-lives and the occurrence of dimethylformamide (DMF) as a residual solvent. While the losses resulting from the radionuclide decay can be minimised by shortening the duration of the process, the best solution for reducing the content of DMF is its elimination from the reaction environment. In the current work two methods are compared for [11C]-choline synthesis - a green chemistry approach (with ethanol as a green solvent) and a dry synthesis. The results were compared with each other and with those of the method based on DMF. The solid phase synthesis proved to be the most effective in total elimination of DMF, its final release was the highest, and the synthesis time was the shortest. The optimised synthesis led to the formation of the desired radiotracer with a high radiochemical yield (65% ±3%) in a short production time (12 min) and the residual precursor in the final product at the level of 1 µg/ml. 27% increase of the saturation yield was possible, which resulted in 9 GBq higher activity from 40 minutes of beaming. Each test batch passed all standard quality control requirements, and the levels of residual DMEA were below the limits that have been published in the last Pharmacopoeia monograph.