Combined effects of radiation and simulated microgravity on intestinal tumorigenesis in C3B6F1 ApcMin/+ mice.

Explorations of the Moon and Mars are planned as future manned space missions, during which humans will be exposed to both radiation and microgravity. We do not, however, know the health effects for such combined exposures. In a ground-based experiment, we evaluated the combined effects of radiation and simulated microgravity on tumorigenesis by performing X-irradiation and tail suspension in C3B6F1 ApcMin/+ mice, a well-established model for intestinal tumorigenesis. Mice were irradiated at 2 weeks of age and underwent tail suspension for 3 or 11 weeks using a special device that avoids damage to the tail. The tail suspension treatment significantly reduced the thymus weight after 3 weeks but not 11 weeks, suggesting a transient stress response. The combination of irradiation and tail suspension significantly increased the number of small intestinal tumors less than 2 mm in diameter as compared with either treatment alone. The combined treatment also increased the fraction of malignant tumors among all small intestinal tumors as compared with the radiation-only treatment. Thus, the C3B6F1 ApcMin/+ mouse is a useful model for assessing cancer risk in a simulated space environment, in which simulated microgravity accelerates tumor progression when combined with radiation exposure.

Prolonged SARS-CoV-2 infection during obinutuzumab and bendamustine treatment for follicular lymphoma: A case report.

Key Clinical Message: SARS-CoV-2 infection has been associated with a prolonged course and a poor prognosis in patients who receive anti-CD20 antibodies. However, there are no established treatments for such patients. Serial changes in the SARS-CoV-2 antigen titer during the clinical course and treatment strategies for immunosuppressed patients are discussed. Abstract: We report a case of prolonged SARS-CoV-2 infection during obinutuzumab and bendamustine treatment for follicular lymphoma. Four years previously, the patient had been diagnosed with follicular lymphoma (Stage IIIA, Grade 2). She received several chemotherapy regimens, including rituximab and radiation therapy. Although these therapies achieved complete response temporally, they did not continue and recurred at 8 months before. Obinutuzumab and bendamustine therapy was selected, and she received five courses of obinutuzumab and bendamustine. She also received a SARS-CoV-2 mRNA vaccine two times. Although she did not have any symptoms, a routine check-up just before the 6th course of obinutuzumab and bendamustine revealed SARS-CoV-2 infection. Because she was immunosuppressed and was considered to be at high risk for the exacerbation of her disease, molnupiravir was immediately administered, and her SARS-CoV-2 antigen decreased. However, it was not completely cleared and flared-up at 6 weeks, with symptoms of COVID-19 appearing. Despite intensive treatment for SARS-CoV-2 infection, including remdesivir, baricitinib, tocilizumab and intravenous immunoglobulin, her SARS-CoV-2 antigen titer never became negative, and she finally died of respiratory failure caused by prolonged SARS-CoV-2 infection. Serial changes in the SARS-CoV-2 antigen titer during the clinical course and treatment strategies for immunosuppressed patients are discussed.

Anti-Metastatic Benefits Produced by Hyperthermia and a CCL3 Derivative.

Significant numbers of malignant tumor cells that have spread to surrounding tissues and other distant organs are often too small to be picked up in a diagnostic test, and prevention of even such small metastases should improve patient outcomes. Using a mouse model, we show in this article that intravenous administration of a human CCL3 variant carrying a single amino acid substitution after mild local hyperthermia not only induces tumor growth inhibition at the treated site but also inhibits metastasis. Colon26 adenocarcinoma cells (1 × 105 cells/mouse) were grafted subcutaneously into the right hind leg of syngeneic BALB/c mice and after nine days, when tumor size reached ~11 mm in diameter, the local tumor mass was exposed to high-frequency waves, by which intratumoral temperature was maintained at 42 °C for 30 min. Mice received the CCL3 variant named eMIP (2 µg/mouse/day) intravenously for five consecutive days starting one day after heat treatment. We found that tumor growth in eMIP recipients after hyperthermia was inhibited markedly but no effect was seen in animals treated with either hyperthermia or eMIP alone. Furthermore, the number of lung metastases evaluated after 18 days was dramatically reduced in animals receiving the combination therapy compared with all other controls. These results encourage future clinical application of this combination therapy.

Radiation enhanced the local and distant anti-tumor efficacy in dual immune checkpoint blockade therapy in osteosarcoma.

Radiation therapy has been long utilized as localized cancer treatment. Recent studies have also demonstrated that it has a distant effect by the enhanced immunity, but it rarely occurs. The purpose of this study was to investigate whether X-ray irradiation combined with anti-PD-L1 and anti-CTLA-4 antibodies (P1C4) provides a higher probability of this distant effect as well as enhanced local antitumor efficacy for osteosarcoma. LM8 mouse osteosarcoma cells were inoculated into both legs of C3H mice assigned to one of four groups, namely no treatment (No Tx), P1C4, X-ray irradiation (RAD) to the leg of one side, and combination (COMB) groups. Survival and treatment-related immune molecular changes were analyzed. Administration of P1C4 produced a tumor growth delay on day 30 in 18% of the mice. In contrast, combination therapy produced the strongest tumor growth inhibition not only at the irradiated tumor but also at unirradiated tumor in 67% of the mice. Accordingly, lung metastasis in the COMB group was strongly reduced by 98%, with a significant survival benefit. Unirradiated tumor in mice in the COMB group significantly recruited CD8 + tumor-infiltrating lymphocytes with a moderate reduction of Treg, producing a significant increase in the CD8/Treg ratio. These results suggest that radiation enhances the efficacy of P1C4 treatment against distant metastasis as well as local control in osteosarcoma. Our data suggest that radiation therapy combined with dual checkpoint blockade may be a promising therapeutic option for osteosarcoma.