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Since the approval of anti-CTLA4 therapy (ipilimumab) for late-stage melanoma in 2011, the development of anticancer immunotherapy agents has thrived. The success of many immune-checkpoint inhibitors has drastically changed the landscape of cancer treatment. For some types of cancer, monotherapy for targeting immune checkpoint pathways has proven more effective than traditional therapies, and combining immunotherapy with current treatment strategies may yield even better outcomes. Numerous preclinical studies have suggested that combining immunotherapy with radiotherapy could be a promising strategy for synergistic enhancement of treatment efficacy. Radiation delivered to the tumor site affects both tumor cells and surrounding stromal cells. Radiation-induced cancer cell damage exposes tumor-specific antigens that make them visible to immune surveillance and promotes the priming and activation of cytotoxic T cells. Radiation-induced modulation of the tumor microenvironment may also facilitate the recruitment and infiltration of immune cells. This unique relationship is the rationale for combining radiation with immune checkpoint blockade. Enhanced tumor recognition and immune cell targeting with checkpoint blockade may unleash the immune system to eliminate the cancer cells. However, challenges remain to be addressed to maximize the efficacy of this promising combination. Here we summarize the mechanisms of radiation and immune system interaction, and we discuss current challenges in radiation and immune checkpoint blockade therapy and possible future approaches to boost this combination.

Recent reports have shown that very high dose rate radiation (35–100 Gy/second) referred to as FLASH tends to spare the normal tissues while retaining the therapeutic effect on tumor. We undertook a series of experiments to assess if ultra-high dose rate of 35 Gy/second can spare the immune system in models of radiation induced lymphopenia. We compared the tumoricidal potency of ultra-high dose rate and conventional dose rate radiation using a classical clonogenic assay in murine pancreatic cancer cell lines. We also assessed the lymphocyte sparing potential in cardiac and splenic irradiation models of lymphopenia and assessed the severity of radiation-induced gastrointestinal toxicity triggered by the two dose rate regimes in vivo . Ultra-high dose rate irradiation more potently induces clonogenic cell death than conventional dose rate irradiation with a dose enhancement factor at 10% survival (DEF 10 ) of 1.310 and 1.365 for KPC and Panc02 cell lines, respectively. Ultra-high dose rate was equally potent in depleting CD3, CD4, CD8, and CD19 lymphocyte populations in both cardiac and splenic irradiation models of lymphopenia. Radiation-induced gastrointestinal toxicity was more pronounced and mouse survival (7 days vs . 15 days, p  = 0.0001) was inferior in the ultra-high dose rate arm compared to conventional dose rate arm. These results suggest that, contrary to published data in other models of radiation-induced acute and chronic toxicity, dose rates of 35 Gy/s do not protect mice from the detrimental side effects of irradiation in our models of cardiac and splenic radiation-induced lymphopenia or gastrointestinal mucosal injury.

Background Cancer patients with coronavirus disease 2019 (COVID-19) have been reported to have double the case fatality rate of the general population. Methods A systematic search of PubMed, Embase, and Cochrane Central was done for studies on cancer patients with COVID-19. Pooled proportions were calculated for categorical variables. Odds ratio (OR) and forest plots (random-effects model) were constructed for both primary and secondary outcomes. Results This systematic review of 38 studies and meta-analysis of 181 323 patients from 26 studies included 23 736 cancer patients. Our meta-analysis shows that cancer patients with COVID-19 have a higher likelihood of death (n = 165 980, OR = 2.54, 95% confidence interval [CI] = 1.47 to 4.42), which was largely driven by mortality among patients in China. Cancer patients were more likely to be intubated. Among cancer subtypes, the mortality was highest in hematological malignancies (n = 878, OR = 2.39, 95% CI = 1.17 to 4.87) followed by lung cancer (n = 646, OR = 1.83, 95% CI = 1.00 to 3.37). There was no association between receipt of a particular type of oncologic therapy and mortality. Our study showed that cancer patients affected by COVID-19 are a decade older than the normal population and have a higher proportion of comorbidities. There was insufficient data to assess the association of COVID-19–directed therapy and survival outcomes in cancer patients. Conclusion Cancer patients with COVID-19 disease are at increased risk of mortality and morbidity. A more nuanced understanding of the interaction between cancer-directed therapies and COVID-19–directed therapies is needed. This will require uniform prospective recording of data, possibly in multi-institutional registry databases.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

HSPA5 (BiP, GRP78) has been reported as a potential host-cell receptor for SARS-Cov-2, but its expression profiles on different tissues including tumors, its susceptibility to SARS-Cov-2 virus and severity of its adverse effects on malignant patients are unclear. In the current study, HSPA5 has been found to be expressed ubiquitously in normal tissues and significantly increased in 14 of 31 types of cancer tissues. In lung cancer, mRNA levels of were 253-fold increase than that of . Meanwhile, in both malignant tumors and matched normal samples across almost all cancer types, mRNA levels of were much higher than those of . Higher expression of significantly decreased patient overall survival (OS) in 7 types of cancers. Moreover, systematic analyses found that 7.15% of 5,068 COVID-19 cases have malignant cancer coincidental situations, and the rate of severe events of COVID-19 patients with cancers present a higher trend than that for all COVID-19 patients, showing a significant difference (33.33% vs 16.09%, <0.01). Collectively, these data imply that the tissues with high HSPA5 expression, not low ACE2 expression, are susceptible to be invaded by SARS-CoV-2. Taken together, this study not only indicates the clinical significance of HSPA5 in COVID-19 disease and cancers, but also provides potential clues for further medical treatments and managements of COVID-19 patients.

Skin carcinogenesis is a multistage process consisting of three distinct stages: initiation, promotion and malignant conversion. The multistep nature of cancer is characterized by progressive activation or loss of signaling pathways, which dictate the behavior of tumor cells, its interaction with neighboring cells, local microenvironment and organism. One of the experimental models that have been instrumental in investigating the stages of cancer formation is the mouse multistage skin carcinogenesis protocol. In this model, a carcinogen initiates cells by introducing a mutation in a Ras gene, and the initiated population expands under treatment with phorbol esters, typically 12-Otetradecanoylphorbol-13-acetate (TPA). Eventually initiated cells outgrow the normal epidermal cells to form benign papillomas. Although phorbol esters are the prototypes of tumor promoters in skin, the nature of their interaction with Ras signaling in tumor promotion remains to be determined. RasGRP1 is a member of the guanine nucleotide exchange factor family for Ras that binds with high affinity to ultrapotent diacylglycerol analogs like the phorbol esters. The ability to bind to phorbol esters and to modulate Ras activity, make RasGRP1 an attractive candidate for an additional target of the phorbol esters in skin that could directly link phorbol ester signaling with Ras cascades and the tumorigenic process. Recent work from our lab has demonstrated expression of RasGRP1 in epidermal keratinocytes. Also, further work using a transgenic murine model that overexpresses RasGRP1 in basal keratinocytes has suggested that RasGRP1 participates in the action of tumor promoting phorbol esters like TPA in the skin. However, the relative contribution of RasGRP1 to Ras signals in keratinocytes and its role in tumor promotion and/or progression in response to the phorbol ester TPA in the absence of overexpression remains to be defined. Thus, the overall goal of this study is to investigate if RasGRP1 is a critical link to Ras activation in mouse epidermal keratinocytes in response to tumor promoter TPA and also to ascertain the relative contribution of RasGRP1 in skin carcinogenesis.

Magnetic carbon nano-structures have potential applications in the field of spintronics as they exhibit valuable magnetic properties. Symmetrically sized small fullerene dimers are substitutional doped with nitrogen (electron rich) and boron (electron deficient) atoms to visualize the effect on their magnetic properties. Interaction energies suggests that the resultant dimer structures are energetically favourable and hence can be formed experimentally. There is significant change in the total magnetic moment of dimers of the order of 0.5 uB after the substitution of C atoms with N and B, which can also be seen in the change of density of states. The HOMO-LUMO gaps of spin up and spin down electronic states have finite energy difference which confirm their magnetic behaviour, whereas for non-magnetic doped dimers, the HOMO-LUMO gaps for spin up and down states are degenerate. The optical properties show that the dimers behave as optical semiconductors and are useful in optoelectronic devices. The induced magnetism in these dimers makes them fascinating nanocarbon magnetic materials.

Magnetism in carbon nanostructures is of high scientific interest, which could lead to novel magnetic materials. The magnetic properties of symmetrical and asymmetrical sized small fullerene dimers have been investigated using spin polarized density functional theory. The interaction energies depict that small fullerene cages form stable dimer structures and symmetrical sized fullerene dimers are found more stable than asymmetrical sized dimers. The dimerization of fullerene cages in different modes leads to change in their magnetic properties. The non-magnetic fullerene cages become magnetic after formation of dimer (C20-C20, C24-C24, C32-C32, C40-C40, C20-C24, C40-C44 and C44-C50),whereas the magnetism of magnetic fullerenes is enhanced or lowered after dimerization (C28-C28 C36-C36, C24-C28, C28-C32, C32-C36 and C36-C40). The individual cages of dimer structures show ferromagnetic interactions amongst them and resultant magnetic moment strongly depends on the type of inter-connecting bonds. The magnetism may also be explained based on distortion of carbon cages and change in the density of states (DOS) in dimer configuration. The calculations presented show strong possibility of experimental synthesis of small fullerene based magnetic dimers.

The electronic and magnetic properties of carbon nanobuds have been investigated using density functional theory. The carbon nanobuds are formed by attaching smaller fullerenes (C20, C28, C36 and C40) of variable size with (5,5) ACNT and (5,0) ZCNT. Fullerenes interact strongly with CNT surface having binding energies within the range -0.93eV to -4.06eV. The C-C bond lengths near the attachment region increase from the original C-C bond lengths. The relative stabilities of the nanobuds are closely related to C-C bond lengths and bond angles in cycloaddition reaction. Nanobuds formed by bond cycloaddition are energetically most favorable amongst all cycloadditions. The electronic and magnetic properties of nanobuds depend strongly on electronic properties of its building blocks. The attachment of C20 and C40 on CNTs open up the HOMO-LUMO gaps of nanobuds whereas C28 and C36 results in addition of impurity states near the Fermi level. The total magnetic moment of nanobuds vary from 0.28B to 4.00B which depend on the nature of bonding between fullerene and CNTs. The results outline the potential of nanobuds as hybrid carbon nanostructures and how their properties can be tuned with the size and type of fullerene attached.

Density functional calculations of hybrids consisting of a single wall carbon nanotube and a graphene nanoribbon have been performed. We consider the dependence of the structural, electronic and magnetic properties of the hybrids on the twist angle between their subunits. We calculated the binding energies, pyramidalization angles, Mulliken charge, and HOMO-LUMO gaps as functions of the twist angle. We find that, owing to the asymmetrical spin density distributions of their subunits, the hybrids have finite magnetic moments.