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Genomic instability remains an enabling feature of cancer and promotes malignant transformation. Alterations of DNA damage response (DDR) pathways allow genomic instability, generate neoantigens, upregulate the expression of programmed death ligand 1 (PD-L1) and interact with signaling such as cyclic GMP–AMP synthase-stimulator of interferon genes (cGAS–STING) signaling. Here, we review the basic knowledge of DDR pathways, mechanisms of genomic instability induced by DDR alterations, impacts of DDR alterations on immune system, and the potential applications of DDR alterations as biomarkers and therapeutic targets in cancer immunotherapy., Graphical abstract This review summarizes basic knowledge of DNA damage response (DDR) pathways, mechanisms of genomic instability induced by DDR alterations, impacts of DDR alterations on immune system, and its potential applications as therapeutic targets in cancer immunotherapy.Image 1

Graphical abstract, Even given recent advances in nanomedicine development of breast cancer treatment in recent years and promising results in pre-clinical models, cancer nanomedicines often fail at the clinical trial stage. Limitations of conventional in vitro models include the lack of representation of the stromal population, the absence of a three-dimensional (3D) structure, and a poor representation of inter-tumor and intra-tumor heterogeneity. Herein, we review those cell culture strategies that aim to overcome these limitations, including cell co-cultures, advanced 3D cell cultures, patient-derived cells, bioprinting, and microfluidics systems. The in vivo evaluation of nanomedicines must consider critical parameters that include the enhanced permeability and retention effect, the host's immune status, and the site of tumor implantation. Here, we critically discuss the advantages and limitations of current in vivo models and report how the improved selection and application of breast cancer models can improve the clinical translation of nanomedicines.

Background & Aims The association between cellular senescence and Helicobacter pylori–induced atrophic gastritis is not clear. Here, we explore the role of cellular senescence in H pylori–induced atrophic gastritis and the underlying mechanism. Methods C57BL/6J mice were infected with H pylori for biological and mechanistic studies in vivo. Gastric precancerous lesions from patients and mouse models were collected and analyzed using senescence-associated beta-galactosidase, Sudan Black B, and immunohistochemical staining to analyze senescent cells, signaling pathways, and H pylori infection. Chromatin immunoprecipitation, luciferase reporter assays, and other techniques were used to explore the underlying mechanism in vitro. Results Gastric mucosa atrophy was highly associated with cellular senescence. H pylori promoted gastric epithelial cell senescence in vitro and in vivo in a manner that depended on C-X-C motif chemokine receptor 2 (CXCR2) signaling. Interestingly, H pylori infection not only up-regulated the expression of CXCR2 ligands, C-X-C motif chemokine ligands 1 and 8, but also transcriptionally up-regulated the expression of CXCR2 via the nuclear factor-κB subunit 1 directly. In addition, CXCR2 formed a positive feedback loop with p53 to continually enhance senescence. Pharmaceutical inhibition of CXCR2 in an H pylori–infected mouse model attenuated mucosal senescence and atrophy, and delayed further precancerous lesion progression. Conclusions Our study showed a new mechanism of H pylori–induced atrophic gastritis through CXCR2-mediated cellular senescence. Inhibition of CXCR2 signaling is suggested as a potential preventive therapy for targeting H pylori–induced atrophic gastritis. GEO data set accession numbers: GSE47797 and GSE3556., Graphical abstract

Patient-derived xenograft (PDX) tumor models represent a valuable platform for identifying new biomarkers and novel targets, to evaluate therapy response and resistance mechanisms. This study aimed at establishment, characterization and therapy testing of colorectal carcinoma-derived PDX. We generated 49 PDX and validated identity between patient tumor and corresponding PDX. Sensitivity of PDX toward conventional and targeted drugs revealed that 92% of PDX responded toward irinotecan, 45% toward 5-FU, 65% toward bevacizumab, and 61% toward cetuximab. Expression of epidermal growth factor receptor (EGFR) ligands correlated to the sensitivity toward cetuximab. Proto-oncogene B-RAF, EGFR, Kirsten rat sarcoma virus oncogene homolog gene copy number correlated positively with cetuximab and erlotinib sensitivity. The mutational analyses revealed an individual mutational profile of PDX and mainly identical profiles of PDX from primary tumor vs corresponding metastasis. Mutation in PIK3CA was a determinant of accelerated tumor doubling time. PDX with wildtype Kirsten rat sarcoma virus oncogene homolog, proto-oncogene B-RAF, and phosphatidylinositol-4,5-bisphosphate 3-kinaseM catalytic subunit alfa showed higher sensitivity toward cetuximab and erlotinib. To study the molecular mechanism of cetuximab resistance, cetuximab resistant PDX models were generated, and changes in HER2, HER3, betacellulin, transforming growth factor alfa were observed. Global proteome and phosphoproteome profiling showed a reduction in canonical EGFR-mediated signaling via PTPN11 (SHP2) and AKT1S1 (PRAS40) and an increase in anti-apoptotic signaling as a consequence of acquired cetuximab resistance. This demonstrates that PDX models provide a multitude of possibilities to identify and validate biomarkers, signaling pathways and resistance mechanisms for clinically relevant improvement in cancer therapy.

Breast cancer therapy using anticancer bioactive compounds derived from natural products as adjuvant treatment has gained recognition due to expensive and toxic conventional chemotherapeutic drugs. The whole plant of Anastatica hierochuntica (L.) (A. hierochuntica) has been investigated for its pharmacologically important anticancer properties but without categorizing the biological activities of the plant parts. We assessed the anticancer potential of different parts of A. hierochuntica (seeds, stems and leaves) and explored their mechanisms of action using the human breast cancer cell line, MCF-7. Currently, we investigated the antiproliferative effects of methanolic (MSD, MST, ML) and aqueous (ASD, AST, AL) extracts of A. hierochuntica plant parts on the MCF-7 cells using cell viability assays. Flow cytometry, Western Blot, DNA fragmentation, and gene expression assays were performed to evaluate apoptosis and cell cycle regulatory proteins. The results indicate that the methanolic and aqueous extracts decreased MCF-7 cell viability in a dose-dependent manner. The induction of apoptosis was observed in all the methanolic and aqueous-treated MCF-7 cells. The cell death process was confirmed by the visualization of DNA fragmentation and cleavage of the intrinsic apoptotic pathways, caspase-9 and caspase-3, the key enzyme causing apoptosis hallmarks. In addition, the most pro-apoptotic extracts, ASD and ML, up-regulated the expression of pro-apoptotic Bax, tumor suppressor TP53 genes and the cyclin inhibitor CDKN1A gene. In conclusion, of the aqueous and methanolic extracts of A. hierochuntica plant parts exerting antiproliferative effects through the induction of apoptosis in breast cancer MCF-7 cells, ASD and ML extracts were the most promising natural-based drugs for the treatment of breast cancer.

Background DNA damage repair (DDR) alterations are important events in cancer initiation, progression, and therapeutic resistance. However, the involvement of DDR alterations in glioma malignancy needs further investigation. This study aims to characterize the clinical and molecular features of gliomas with DDR alterations and elucidate the biological process of DDR alterations that regulate the cross talk between gliomas and the tumor microenvironment. Methods Integrated transcriptomic and genomic analyses were undertaken to conduct a comprehensive investigation of the role of DDR alterations in glioma. The prognostic DDR-related cytokines were identified from multiple datasets. In vivo and in vitro experiments validated the role of p53, the key molecule of DDR, regulating M2 polarization of microglia in glioma. Findings DDR alterations are associated with clinical and molecular characteristics of glioma. Gliomas with DDR alterations exhibit distinct immune phenotypes, and immune cell types and cytokine processes. DDR-related cytokines have an unfavorable prognostic implication for GBM patients and are synergistic with DDR alterations. Overexpression of MDK mediated by p53, the key transcriptional factor in DDR pathways, remodels the GBM immunosuppressive microenvironment by promoting M2 polarization of microglia, suggesting a potential role of DDR in regulating the glioma microenvironment. Interpretation Our work suggests that DDR alterations significantly contribute to remodeling the glioma microenvironment via regulating the immune response and cytokine pathways. Fund This study was supported by: 1. The National Key Research and Development Plan (No. 2016YFC0902500); 2. National Natural Science Foundation of China (No. 81702972, No. 81874204, No. 81572701, No. 81772666); 3. China Postdoctoral Science Foundation (2018M640305); 4. Special Fund Project of Translational Medicine in the Chinese-Russian Medical Research Center (No. CR201812); 5. The Research Project of the Chinese Society of Neuro-oncology, CACA (CSNO-2016-MSD12); 6. The Research Project of the Health and Family Planning Commission of Heilongjiang Province (2017–201); and 7. Harbin Medical University Innovation Fund (2017LCZX37, 2017RWZX03)., Highlights • Gliomas with DNA damage repair alterations had distinct genomic variation spectrum. • DDR alterations exhibit distinct immune phenotypes, cytokine processes and immune cell types in glioma. • DDR-related cytokines in GME have an unfavorable prognostic implication for GBM patients. • P53-mediated midkine expression derived from glioma cells promotes M2 polarization of microglia.

Background Our understanding of adaptive immune responses in COVID-19 patients is rapidly evolving, but information on the innate immune responses by natural killer (NK) cells is still insufficient. Objective We aimed to examine the phenotypic and functional status of NK cells and their changes during the course of mild and severe COVID-19. Methods We performed RNA sequencing (RNA-seq) and flow cytometric analysis of NK cells from patients with mild and severe COVID-19 at multiple time points in the course of the disease using cryopreserved peripheral blood mononuclear cells (PBMCs). Results In RNA-seq analysis, the NK cells exhibited distinctive features compared to healthy donors, with significant enrichment of pro-inflammatory cytokine-mediated signaling pathways. Intriguingly, we found that the unconventional CD56dimCD16neg (uCD56dim) NK cell population expanded in cryopreserved PBMCs from COVID-19 patients regardless of disease severity, accompanied by decreased NK cell cytotoxicity. The NK cell population was rapidly normalized alongside the disappearance of uCD56dim NK cells and the recovery of NK cell cytotoxicity in mild COVID-19 patients, but this occurred slowly in severe COVID-19 patients. Conclusion The current longitudinal study provides a deep understanding of the NK cell biology in COVID-19., Graphical abstract

Sclerostin antibody (Scl-Ab) stimulates bone formation, which with long-term treatment, attenuates over time. The cellular and molecular mechanisms responsible for the attenuation of bone formation are not well understood, but in aged ovariectomized (OVX) rats, the reduction in vertebral cancellous bone formation is preceded by a reduction in osteoprogenitor (OP) number and significant induction of signaling pathways known to suppress mitogenesis and cell cycle progression in the osteocyte (OCy) (Taylor et al., 2016). To determine if the reduction in OP number is associated with a decrease in proliferation, aged OVX rats were administered vehicle or Scl-Ab for 9 or 29 days and implanted with continuous-delivery 5-bromo-2′-deoxyuridine (BrdU) mini-osmotic pumps 5 days prior to necropsy. The total number of BrdU-labeled osteoblasts (OB) was quantified in vertebral cancellous bone to indirectly assess the effects of Scl-Ab treatment on OP proliferation at the time of activation of modeling-based bone formation at day 9 and at the time of maximal mineralizing surface, initial decrease in OP number, and transcriptional changes in the OCy at day 29. Compared with vehicle, Scl-Ab resulted in an increase in the total number of BrdU-positive OB (+260%) at day 9 that decreased with continued treatment (+50%) at day 29. These differences in proliferation occurred at time points when the increase in total OB number was significant and similar in magnitude. These findings suggest that reduced OP proliferation contributes to the decrease in OP numbers, an effect that would limit the OB pool and contribute to the attenuation of bone formation that occurs with long-term Scl-Ab treatment., Highlights • Sclerostin antibody stimulates bone formation (BF) that attenuates over time. • Osteoprogenitor (OP) proliferation increases early with treatment. • Attenuation of BF is preceded by a decrease in OP proliferation. • Decrease is coincident with molecular signaling consistent with cell cycle arrest. • Decreased OP proliferation contributes to the attenuation of BF.

Highlights • Diabetes mellitus and hyperglycemia significantly affect the incidence and prognosis of colorectal cancer. • Evidence of the effects of metformin remain controversial in cancer prognosis. • Potential molecular mechanisms by which DM and hyperglycemia affects cancer risk. • Potential roles of glucose modulation in CRC therapy., Diabetes mellitus (DM) and hyperglycemia have been shown to have significant effects on the incidence, chemoresistance, and prognosis of colorectal cancer (CRC), as well as the outcomes of localized and metastatic CRC. Inflammation and endocrine effects may act as central mechanisms of DM and cancer and stimulate the insulin‐like growth factor 1–phosphoinositide 3-kinase–Akt–mammalian target of rapamycin (IGF-1–PI3K–AKT–mTOR) pathway. Dysregulation of the AMP-activated protein kinase (AMPK) pathway leads to metabolic imbalance and indicates cancer risk. The use of metformin for chemoprevention has been shown to reduce CRC and adenoma incidence through the upregulation of AMPK, which causes cell cycle arrest in the Gap 1–S (G1–S) phase and inhibits the mTOR pathway, even potentially reversing the epithelial–mesenchymal transition. However, evidence of the effects of metformin remain controversial in cancer prognosis. Several genes, such as transcription factor 7-like 2(TCF7L2), tumor protein P53 inducible nuclear protein 1(TP53INP1), gremlin 1 (GREM1), and potassium voltage-gated channel subfamily Q member 1(KCNQ1), are pleiotropically related to DM as well as cancer risk and prognosis. Epigenetic modification of members of the Let-7 family such as miR-497, miR-486, and miR-223 is strongly associated with impaired glucose tolerance and CRC risk. Herein we review the pathophysiological and epidemiological evidence as well as potential underlying molecular mechanisms by which DM and hyperglycemia affect CRC risk. We also suggest potential roles of glucose modulation in CRC therapy and propose an agenda for future research and clinical practice., Graphical abstract Image, graphical abstract

Summary Biliary tract cancers (BTCs) are aggressive epithelial malignancies that can arise at any point of the biliary tree. Albeit rare, their incidence and mortality rates have been rising steadily over the past 40 years, highlighting the need to improve current diagnostic and therapeutic strategies. BTCs show high inter- and intra-tumour heterogeneity both at the morphological and molecular level. Such complex heterogeneity poses a substantial obstacle to effective interventions. It is widely accepted that the observed heterogeneity may be the result of a complex interplay of different elements, including risk factors, distinct molecular alterations and multiple potential cells of origin. The use of genetic lineage tracing systems in experimental models has identified cholangiocytes, hepatocytes and/or progenitor-like cells as the cells of origin of BTCs. Genomic evidence in support of the distinct cell of origin hypotheses is growing. In this review, we focus on recent advances in the histopathological subtyping of BTCs, discuss current genomic evidence and outline lineage tracing studies that have contributed to the current knowledge surrounding the cell of origin of these tumours.

Metabolic imaging of brain tumors using 13C Magnetic Resonance Spectroscopy (MRS) of hyperpolarized [1-13C] pyruvate is a promising neuroimaging strategy which, after a decade of preclinical success in glioblastoma (GBM) models, is now entering clinical trials in multiple centers. Typically, the presence of GBM has been associated with elevated hyperpolarized [1-13C] lactate produced from [1-13C] pyruvate, and response to therapy has been associated with a drop in hyperpolarized [1-13C] lactate. However, to date, lower grade gliomas had not been investigated using this approach. The most prevalent mutation in lower grade gliomas is the isocitrate dehydrogenase 1 (IDH1) mutation, which, in addition to initiating tumor development, also induces metabolic reprogramming. In particular, mutant IDH1 gliomas are associated with low levels of lactate dehydrogenase A (LDHA) and monocarboxylate transporters 1 and 4 (MCT1, MCT4), three proteins involved in pyruvate metabolism to lactate. We therefore investigated the potential of 13C MRS of hyperpolarized [1-13C] pyruvate for detection of mutant IDH1 gliomas and for monitoring of their therapeutic response. We studied patient-derived mutant IDH1 glioma cells that underexpress LDHA, MCT1 and MCT4, and wild-type IDH1 GBM cells that express high levels of these proteins. Mutant IDH1 cells and tumors produced significantly less hyperpolarized [1-13C] lactate compared to GBM, consistent with their metabolic reprogramming. Furthermore, hyperpolarized [1-13C] lactate production was not affected by chemotherapeutic treatment with temozolomide (TMZ) in mutant IDH1 tumors, in contrast to previous reports in GBM. Our results demonstrate the unusual metabolic imaging profile of mutant IDH1 gliomas, which, when combined with other clinically available imaging methods, could be used to detect the presence of the IDH1 mutation in vivo., Graphical abstract Image 1, Highlights • Metabolic imaging of mutant IDH1 gliomas using hyperpolarized 13C MRS is described. • In contrast to GBM, mutant IDH1 gliomas produce no hyperpolarized [1-13C] lactate. • Hyperpolarized [1-13C] lactate is not reduced by treatment in mutant IDH1 tumors. • Mutant IDH1 gliomas present an unusual metabolic imaging profile.