Immune response to RB1-regulated senescence limits radiation-induced osteosarcoma formation

Tumor biomarkers for diagnosis, prognosis and targeted therapy

Tumor biomarkers, the substances which are produced by tumors or the body's responses to tumors during tumorigenesis and progression, have been demonstrated to possess critical and encouraging value in screening and early diagnosis, prognosis prediction, recurrence detection, and therapeutic efficacy monitoring of cancers. Over the past decades, continuous progress has been made in exploring and discovering novel, sensitive, specific, and accurate tumor biomarkers, which has significantly promoted personalized medicine and improved the outcomes of cancer patients, especially advances in molecular biology technologies developed for the detection of tumor biomarkers. Herein, we summarize the discovery and development of tumor biomarkers, including the history of tumor biomarkers, the conventional and innovative technologies used for biomarker discovery and detection, the classification of tumor biomarkers based on tissue origins, and the application of tumor biomarkers in clinical cancer management. In particular, we highlight the recent advancements in biomarker-based anticancer-targeted therapies which are emerging as breakthroughs and promising cancer therapeutic strategies. We also discuss limitations and challenges that need to be addressed and provide insights and perspectives to turn challenges into opportunities in this field. Collectively, the discovery and application of multiple tumor biomarkers emphasized in this review may provide guidance on improved precision medicine, broaden horizons in future research directions, and expedite the clinical classification of cancer patients according to their molecular biomarkers rather than organs of origin.

The impact of the senescent microenvironment on tumorigenesis: Insights for cancer therapy

The growing global burden of cancer, especially among people aged 60 years and over, has become a key public health issue. This trend suggests the need for a deeper understanding of the various cancer types in order to develop universally effective treatments. A prospective area of research involves elucidating the interplay between the senescent microenvironment and tumor genesis. Currently, most oncology research focuses on adulthood and tends to ignore the potential role of senescent individuals on tumor progression. Senescent cells produce a senescence-associated secretory phenotype (SASP) that has a dual role in the tumor microenvironment (TME). While SASP components can remodel the TME and thus hinder tumor cell proliferation, they can also promote tumorigenesis and progression via pro-inflammatory and pro-proliferative mechanisms. To address this gap, our review seeks to investigate the influence of senescent microenvironment changes on tumor development and their potential implications for cancer therapies.

Therapeutic Strategies for RB1-Deficient Cancers: Intersecting Gene Regulation and Targeted Therapy

The retinoblastoma (RB) transcriptional corepressor 1 (RB1) is a critical tumor suppressor gene, governing diverse cellular processes implicated in cancer biology. Dysregulation or deletion in RB1 contributes to the development and progression of various cancers, making it a prime target for therapeutic intervention. RB1's canonical function in cell cycle control and DNA repair mechanisms underscores its significance in restraining aberrant cell growth and maintaining genomic stability. Understanding the complex interplay between RB1 and cellular pathways is beneficial to fully elucidate its tumor-suppressive role across different cancer types and for therapeutic development. As a result, investigating vulnerabilities arising from RB1 deletion-associated mechanisms offers promising avenues for targeted therapy. Recently, several findings highlighted multiple methods as a promising strategy for combating tumor growth driven by RB1 loss, offering potential clinical benefits in various cancer types. This review summarizes the multifaceted role of RB1 in cancer biology and its implications for targeted therapy.

Discovery of potent thiazolidin-4-one sulfone derivatives for inhibition of proliferation of osteosarcoma in vitro and in vivo

Chemotherapy combining with surgical treatment has been the main strategy for osteosarcoma treatment in clinical. Due to unclear pathogenesis and unidentified drug targets, significant progress has not been made in the development of targeted drugs for osteosarcoma during the past 50 years. Our previous discovery reported compound R-8i with a high potency for the treatment of osteosarcoma by phenotypic screening. However, both the metabolic stability and bioavailability of R-8i are poor (T1/2 = 5.36 min, mouse liver microsome; and bioavailability in vivo F = 52.1 %, intraperitoneal administration) which limits it use for further drug development. Here, we described an extensive structure-activity relationship study of thiazolidine-4-one sulfone inhibitors from R-8i, which led to the discovery of compound 68. Compound 68 had a potent cellular activity with an IC50 value of 0.217 μM, much higher half-life (T1/2 = 73.8 min, mouse liver microsome) and an excellent pharmacokinetic profile (in vivo bioavailability F = 115 %, intraperitoneal administration). Compound 68 also showed good antitumor effects and low toxicity in a xenograft model (44.6 % inhibition osteosarcoma growth in BALB/c mice). These results suggest that compound 68 is a potential drug candidate for the treatment of osteosarcoma.

Spatiotemporal transformable nano-assembly for on-demand drug delivery to enhance anti-tumor immunotherapy

Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy, but fibrotic matrix severely blocks senescence inducers penetration and immune cells infiltration. Herein, we designed a cancer-associated fibroblasts (CAFs) triggered structure-transformable nano-assembly (HSD-P@V), which can directionally deliver valsartan (Val, CAFs regulator) and doxorubicin (DOX, senescence inducer) to the specific targets. In detail, DOX is conjugated with hyaluronic acid (HA) via diselenide bonds (Se-Se) to form HSD micelles, while CAFs-sensitive peptide is grafted onto the HSD to form a hydrophilic polymer, which is coated on Val nanocrystals (VNs) surface for improving the stability and achieving responsive release. Once arriving at tumor microenvironment and touching CAFs, HSD-P@V disintegrates into VNs and HSD micelles due to sensitive peptide detachment. VNs can degrade the extracellular matrix, leading to the enhanced penetration of HSD. HSD targets tumor cells, releases DOX to induce senescence, and recruits effector immune cells. Furthermore, senescent cells are cleared by the recruited immune cells to finish the integrated anti-tumor therapy. In vitro and in vivo results show that the nano-assembly remarkably inhibits tumor growth as well as lung metastasis, and extends tumor-bearing mice survival. This work provides a promising paradigm of programmed delivering multi-site nanomedicine for cancer immunotherapy.

Twenty-year outcome of prevalence, incidence, mortality and survival rate in patients with malignant bone tumors

Malignant bone tumors are a group of rare malignant tumors and our study aimed to update the recent epidemiologic estimates based on the Surveillance, Epidemiology and End Results database. Patients diagnosed with malignant bone tumors from 2000 to 2019 were included and their characteristics were retrospectively described. The limited-duration prevalence, annual age-adjusted incidence and mortality were calculated, and the annual percentage changes were analyzed to quantify the rate change. Finally, observed survival and relative survival rate were illustrated. Subgroup analysis across tumor type, age, gender, tumor Grade, primary tumor site and stage was also performed. As for results, a total of 11 655 eligible patients with malignant bone tumor were selected. Osteosarcoma was the most common tumor type, followed by chondrosarcoma, Ewing sarcoma and chordoma. The estimated limited-duration prevalence of malignant bone tumors increased from 2000 (0.00069%) to 2018 (0.00749%). Steady age-adjusted incidence was observed in all patients during the study period while the highest rate occurred in osteosarcoma. Mortality rates differed in subgroups while elder patients (older than 64 years) presented the highest mortality rate compared to other age groups. In all bone tumors, the 10-year observed survival and relative survival rates were 58.0% and 61.9%, respectively. Chondrosarcoma patients had the best survival outcome, followed by osteosarcoma, Ewing sarcoma, chordoma and other bone tumors. In conclusion, different epidemiologic performance in incidence and mortality was observed across tumor type as well as other demographic and clinicopathological variables, which provide potential suggestion for further adjustment of medical resource.

[Tumor-immune cell interaction and senescence-associated molecules in colorectal carcinoma]

BACKGROUND

Cellular senescence permanently arrests the cell cycle of premalignant cells following protumorigenic stimuli, counteracting tumor progression. Senescence induction leads to phenotypic and metabolic changes and alters the interaction with the cells' microenvironment. This mediates tumor immunosurveillance but bears promalignant potential and may contribute to disease progression.

OBJECTIVES

Our study aims to investigate the prognostic potential of senescence markers in colorectal carcinoma (CRC) and to understand the interaction of senescent tumor cells and immune cells.

MATERIALS AND METHODS

Immunohistochemical markers were studied on a tissue microarray (TMA) containing tumor tissue of n = 598 CRC patients and were evaluated using digital image analysis. Results were correlated with disease-specific survival (DSS) and progression-free survival (PFS). Consecutive TMA sections were stained for senescence markers and immune cell markers to analyze the spatial relation of those cell populations. Senescence was induced in CRC cell lines in vitro and co-cultures with various immune cell lines were established to study the interactions.

RESULTS

Expression of different senescent-associated markers is associated with increased or decreased DSS and PFS. Close proximity of p21+ senescent tumor cells and CD8+ immune cells correlates with increased DSS and PFS. In vitro, senescent cells were dose-dependently eliminated by immune cells, which is facilitated via direct cell-cell contact and induction of apoptosis.

CONCLUSIONS

Depicting the initiation of this important anti-tumor mechanism, markers of cellular senescence are of significant prognostic relevance in CRC. Moreover, our results show the pleiotropic effect of senescence in vivo. Absence as well as exceeding expression of senescence markers are associated with a negative prognosis in CRC. The impact of cellular senescence depends on the tumor microenvironment and the immunosurveillance of senescent cells. Proximity analyses of senescent cells and tumor-infiltrating immune cells have significant prognostic relevance and reflect this.

Tumor cell-induced macrophage senescence plays a pivotal role in tumor initiation followed by stable growth in immunocompetent condition

BACKGROUND

The cancer stem cell theory proposes that tumor formation in vivo is driven only by specific tumor-initiating cells having stemness; however, clinical trials conducted to test drugs that target the tumor stemness provided unsatisfactory results thus far. Recent studies showed clear involvement of immunity in tumors; however, the requirements of tumor-initiation followed by stable growth in immunocompetent individuals remain largely unknown.

METHODS

To clarify this, we used two similarly induced glioblastoma lines, 8B and 9G. They were both established by overexpression of an oncogenic H-RasL61 in p53-deficient neural stem cells. In immunocompromised animals in an orthotopic transplantation model using 1000 cells, both show tumor-forming potential. On the other hand, although in immunocompetent animals, 8B shows similar tumor-forming potential but that of 9G's are very poor. This suggests that 8B cells are tumor-initiating cells in immunocompetent animals. Therefore, we hypothesized that the differences in the interaction properties of 8B and 9G with immune cells could be used to identify the factors responsible for its tumor forming potential in immunocompetent animals and performed analysis.

RESULTS

Different from 9G, 8B cells induced senescence-like state of macrophages around tumors. We investigated the senescence-inducing factor of macrophages by 8B cells and found that it was interleukin 6. Such senescence-like macrophages produced Arginase-1, an immunosuppressive molecule known to contribute to T-cell hyporesponsiveness. The senescence-like macrophages highly expressed CD38, a nicotinamide adenine dinucleotide (NAD) glycohydrolase associated with NAD shortage in senescent cells. The addition of nicotinamide mononucleotide (NMN), an NAD precursor, in vitro inhibited to the induction of macrophage senescence-like phenotype and inhibited Arginase-1 expression resulting in retaining T-cell function. Moreover, exogenous in vivo administration of NMN after tumor inoculation inhibited tumor-initiation followed by stable growth in the immunocompetent mouse tumor model.

CONCLUSIONS

We identified one of the requirements for tumor-initiating cells in immunocompetent animals. In addition, we have shown that tumor growth can be inhibited by externally administered NMN against macrophage senescence-like state that occurs in the very early stages of tumor-initiating cell development. This therapy targeting the immunosuppressive environment formed by macrophage senescence-like state is expected to be a novel promising cancer therapeutic strategy.

Cytotoxic CD4+ T cells eliminate senescent cells by targeting cytomegalovirus antigen

Senescent cell accumulation has been implicated in the pathogenesis of aging-associated diseases, including cancer. The mechanism that prevents the accumulation of senescent cells in aging human organs is unclear. Here, we demonstrate that a virus-immune axis controls the senescent fibroblast accumulation in the human skin. Senescent fibroblasts increased in old skin compared with young skin. However, they did not increase with advancing age in the elderly. Increased CXCL9 and cytotoxic CD4+ T cells (CD4 CTLs) recruitment were significantly associated with reduced senescent fibroblasts in the old skin. Senescent fibroblasts expressed human leukocyte antigen class II (HLA-II) and human cytomegalovirus glycoprotein B (HCMV-gB), becoming direct CD4 CTL targets. Skin-resident CD4 CTLs eliminated HCMV-gB+ senescent fibroblasts in an HLA-II-dependent manner, and HCMV-gB activated CD4 CTLs from the human skin. Collectively, our findings demonstrate HCMV reactivation in senescent cells, which CD4 CTLs can directly eliminate through the recognition of the HCMV-gB antigen.

Aging microenvironment and antitumor immunity for geriatric oncology: the landscape and future implications

The tumor microenvironment (TME) has been extensively investigated; however, it is complex and remains unclear, especially in elderly patients. Senescence is a cellular response to a variety of stress signals, which is characterized by stable arrest of the cell cycle and major changes in cell morphology and physiology. To the best of our knowledge, senescence leads to consistent arrest of tumor cells and remodeling of the tumor-immune microenvironment (TIME) by activating a set of pleiotropic cytokines, chemokines, growth factors, and proteinases, which constitute the senescence-associated secretory phenotype (SASP). On the one hand, the SASP promotes antitumor immunity, which enhances treatment efficacy; on the other hand, the SASP increases immunosuppressive cell infiltration, including myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), M2 macrophages, and N2 neutrophils, contributing to TIME suppression. Therefore, a deeper understanding of the regulation of the SASP and components contributing to robust antitumor immunity in elderly individuals with different cancer types and the available therapies is necessary to control tumor cell senescence and provide greater clinical benefits to patients. In this review, we summarize the key biological functions mediated by cytokines and intercellular interactions and significant components of the TME landscape, which influence the immunotherapy response in geriatric oncology. Furthermore, we summarize recent advances in clinical practices targeting TME components and discuss potential senescent TME targets.

Senescence and the tumor-immune landscape: Implications for cancer immunotherapy

Cancer therapies, including conventional chemotherapy, radiation, and molecularly targeted agents, can lead to tumor eradication through a variety of mechanisms. In addition to their effects on tumor cell growth and survival, these regimens can also influence the surrounding tumor-immune microenvironment in ways that ultimately impact therapy responses. A unique biological outcome of cancer therapy is induction of cellular senescence. Senescence is a damage-induced stress program that leads to both the durable arrest of tumor cells and remodeling the tumor-immune microenvironment through activation of a collection pleiotropic cytokines, chemokines, growth factors, and proteinases known as the senescence-associated secretory phenotype (SASP). Depending on the cancer context and the mechanism of action of the therapy, the SASP produced following therapy-induced senescence (TIS) can promote anti-tumor immunity that enhances therapeutic efficacy, or alternatively chronic inflammation that leads to therapy failure and tumor relapse. Thus, a deeper understanding of the mechanisms regulating the SASP and components necessary for robust anti-tumor immune surveillance in different cancer and therapy contexts are key to harnessing senescence for tumor control. Here we draw a roadmap to modulate TIS and its immune-stimulating features for cancer immunotherapy.

Integrated multi-omics approach revealed cellular senescence landscape

Cellular senescence is a complex multifactorial biological phenomenon that plays essential roles in aging, and aging-related diseases. During this process, the senescent cells undergo gene expression altering and chromatin structure remodeling. However, studies on the epigenetic landscape of senescence using integrated multi-omics approaches are limited. In this research, we performed ATAC-seq, RNA-seq and ChIP-seq on different senescent types to reveal the landscape of senescence and identify the prime regulatory elements. We also obtained 34 key genes and deduced that NAT1, PBX1 and RRM2, which interacted with each other, could be the potential markers of aging and aging-related diseases. In summary, our work provides the landscape to study accessibility dynamics and transcriptional regulations in cellular senescence. The application of this technique in different types of senescence allows us to identify the regulatory elements responsible for the substantial regulation of transcription, providing the insights into molecular mechanisms of senescence.

Carbohydrate-based drugs launched during 2000-2021

Carbohydrates are fundamental molecules involved in nearly all aspects of lives, such as being involved in formating the genetic and energy materials, supporting the structure of organisms, constituting invasion and host defense systems, and forming antibiotics secondary metabolites. The naturally occurring carbohydrates and their derivatives have been extensively studied as therapeutic agents for the treatment of various diseases. During 2000 to 2021, totally 54 carbohydrate-based drugs which contain carbohydrate moities as the major structural units have been approved as drugs or diagnostic agents. Here we provide a comprehensive review on the chemical structures, activities, and clinical trial results of these carbohydrate-based drugs, which are categorized by their indications into antiviral drugs, antibacterial/antiparasitic drugs, anticancer drugs, antidiabetics drugs, cardiovascular drugs, nervous system drugs, and other agents.

Novel insights into RB1 mutation

Since the discovery of the retinoblastoma susceptibility gene (RB1) decades ago, RB1 has been regarded as a prototype tumor suppressor gene providing a paradigm for tumor genetic research. Constant research has updated the understanding of RB1-related pathways and their impact on tumor and nontumor diseases. Mutation of RB1 gene has been observed in multiple types of malignant tumors including prostate cancer, lung cancer, breast cancer, and almost every familial and sporadic case of retinoblastoma. Even if well-known and long-investigated, the application potential of RB1 mutation has not been fully tapped. In this review, we focus on the mechanism underlying RB1 mutation during oncogenesis. Therapeutically, we have further discussed potential clinical strategies by targeting RB1-mutated cancers. The unsolved problems and prospects of RB1 mutation are also discussed.

MiR-192-5p/RB1/NF-κBp65 signaling axis promotes IL-10 secretion during gastric cancer EMT to induce Treg cell differentiation in the tumour microenvironment

BACKGROUND

Regulatory T (Treg) cells are important components of the tumour microenvironment (TME) that play roles in gastric cancer (GC) metastasis. Although tumour cells that undergo epithelial-mesenchymal transition (EMT) regulate Treg cell function, their regulatory mechanism in GC remains unclear.

METHODS

The miR-192-5p was identified by examining three Gene Expression Omnibus GC miRNA expression datasets. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were conducted to identify interactions between miR-192-5p and RB1. The role of miR-192-5p/RB1 in GC progression was evaluated based on EdU incorporation, wound healing and Transwell assays. An in vitro co-culture assay was performed to measure the effect of miR-192-5p/RB1 on Treg cell differentiation. In vivo experiments were conducted to explore the role of miR-192-5p in GC progression and Treg cell differentiation.

RESULTS

MiR-192-5p was overexpressed in tumour and was associated with poor prognosis in GC. MiR-192-5p bound to the RB1 3'-untranslated region, resulting in GC EMT, proliferation, migration and invasion. MiR-192-5p/RB1 mediated interleukin-10 (IL-10) secretion by regulating nuclear factor-kappaBp65 (NF-κBp65), affecting Treg cell differentiation. NF-κBp65, in turn, promoted miR-192-5p expression and formed a positive feedback loop. Furthermore, in vivo experiments confirmed that miR-192-5p/RB1 promotes GC growth and Treg cell differentiation.

CONCLUSION

Collectively, our studies indicate that miR-192-5p/RB1 promotes EMT of tumour cells, and the miR-192-5p/RB1/NF-κBp65 signaling axis induces Treg cell differentiation by regulating IL-10 secretion in GC. Our results suggest that targeting miR-192-5p/RB1/NF-κBp65 /IL-10 may pave the way for the development of new immune treatments for GC.

Cellular senescence and the tumor microenvironment

The senescence‐associated secretory phenotype (SASP), where senescent cells produce a variety of secreted proteins including inflammatory cytokines, chemokines, matrix remodelling factors, growth factors and so on, plays pivotal but varying roles in the tumour microenvironment. The effects of SASP on the surrounding microenvironment depend on the cell type and process of cellular senescence induction, which is often associated with innate immunity. Via SASP‐mediated paracrine effects, senescent cells can remodel the surrounding tissues by modulating the character of adjacent cells, such as stromal, immune cells, as well as cancer cells. The SASP is associated with both tumour‐suppressive and tumour‐promoting effects, as observed in senescence surveillance effects (tumour‐suppressive) and suppression of anti‐tumour immunity in most senescent cancer‐associated fibroblasts and senescent T cells (tumour‐promoting). In this review, we discuss the features and roles of senescent cells in tumour microenvironment with emphasis on their context‐dependency that determines whether they promote or suppress cancer development. Potential usage of recently developed drugs that suppress the SASP (senomorphics) or selectively kill senescence cells (senolytics) in cancer therapy are also discussed.

RB1 Is an Immune-Related Prognostic Biomarker for Ovarian Cancer

Background

Ovarian cancer (OC) is one of the most lethal gynecologic malignancies and a leading cause of death in the world. Thus, this necessitates identification of prognostic biomarkers which will be helpful in its treatment.

Methods

The gene expression profiles from The Cancer Genome Atlas (TCGA) and GSE31245 were selected as the training cohort and validation cohort, respectively. The Kaplan–Meier (KM) survival analysis was used to analyze the difference in overall survival (OS) between high and low RB transcriptional corepressor 1 (RB1) expression groups. To confirm whether RB1 was an independent risk factor for OC, we constructed a multivariate Cox regression model. Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analyses were conducted to identify the functions of differentially expressed genes (DEGs). The associations of RB1 with immune infiltration and immune checkpoints were studied by the Tumor Immune Estimation Resource (TIMER 2.0) and the Gene Expression Profiling Interactive Analysis (GEPIA). The immunohistochemistry (IHC) was performed to compare the expression level of RB1 in normal tissues and tumor samples, and to predict the prognosis of OC.

Results

The KM survival curve of the TCGA indicated that the OS in the high-risk group was lower than that in the low-risk group (HR = 1.61, 95% CI: 1.28-2.02, P = 3×10^-5), which was validated in GSE31245 (HR = 4.08, 95% CI: 1.21–13.74, P = 0.01) and IHC. Multivariate Cox regression analysis revealed that RB1 was an independent prognostic biomarker (HR = 1.66, 95% CI: 1.31-2.10, P = 2.02×10^-5). Enrichment analysis suggested that the DEGs were mainly involved in cell cycle, DNA replication, and mitochondrial transition. The infiltration levels of fibroblast, neutrophil, monocyte and macrophage were positively correlated with RB1. Furthermore, RB1 was associated with immune checkpoint molecules (CTLA4, LAG3, and CD274). The IHC staining revealed higher expression of RB1 in tumor tissues as compared to that in normal tissues (P = 0.019). Overexpression of RB1 was associated with poor prognosis of OC (P = 0.01).

Conclusion

These findings suggest that RB1 was a novel and immune-related prognostic biomarker for OC, which may be a promising target for OC treatment.

Viral and cellular oncogenes promote immune evasion

Thirteen percent of cancers worldwide are associated with viral infections. While many human oncogenic viruses are widely endemic, very few infected individuals develop cancer. This raises the question why oncogenic viruses encode viral oncogenes if they can replicate and spread between human hosts without causing cancer. Interestingly, viral infection triggers innate immune signaling pathways that in turn activate tumor suppressors such as p53, suggesting that tumor suppressors may have evolved not primarily to prevent cancer, but to thwart viral infection. Here, we summarize and compare several major immune evasion strategies used by viral and non-viral cancers, with a focus on oncogenes that play dual roles in promoting tumorigenicity and immune evasion. By highlighting important and illustrative examples of how oncogenic viruses evade the immune system, we aim to shed light on how non-viral cancers avoid immune detection. Further study and understanding of how viral and non-viral oncogenes impact immune function could lead to improved strategies to combine molecular therapies targeting oncoproteins in combination with immunomodulators.

Novel 2-phenyl-3-(Pyridin-2-yl) thiazolidin-4-one derivatives as potent inhibitors for proliferation of osteosarcoma cells in vitro and in vivo

Due to unknown pathogenesis and unidentified drug target, no drug for the treatment of osteosarcoma (OS) has been launched to the market. Herein, thiazolidinone 1a was discovered as a hit compound by phenotypic screening with an in-house patrimonial collection of structural diversity. The following SAR (Structure-Activity Relationship) study affords the final water-soluble lead compound (R)-8i as a potential inhibitor for the proliferation of OS cells by the modulation of solubility of the compounds with remarkable cellular potency (IC₅₀ = 21.9 nM for MNNG/HOS cells) and in vivo efficacy (52.9% inhibition OS growth in mice), as well as pharmacokinetic properties. (R)-8i also significantly suppresses OS cell migration in vitro and showed to be well-tolerated. Our preliminary investigation shows that the effects of (R)-8i are not dependent on p53 and myoferlin (MYOF). These results suggest that (R)-8i might be a potential drug candidate for OS treatment.

Cellular Senescence: Mechanisms and Therapeutic Potential

Cellular senescence is a complex and multistep biological process which cells can undergo in response to different stresses. Referring to a highly stable cell cycle arrest, cellular senescence can influence a multitude of biological processes-both physiologically and pathologically. While phenotypically diverse, characteristics of senescence include the expression of the senescence-associated secretory phenotype, cell cycle arrest factors, senescence-associated β-galactosidase, morphogenesis, and chromatin remodelling. Persistent senescence is associated with pathologies such as aging, while transient senescence is associated with beneficial programmes, such as limb patterning. With these implications, senescence-based translational studies, namely senotherapy and pro-senescence therapy, are well underway to find the cure to complicated diseases such as cancer and atherosclerosis. Being a subject of major interest only in the recent decades, much remains to be studied, such as regarding the identification of unique biomarkers of senescent cells. This review attempts to provide a comprehensive understanding of the diverse literature on senescence, and discuss the knowledge we have on senescence thus far.

Analysis of mitochondrial regulatory transcripts in publicly available datasets with validation in placentae from pre-term, post-term and fetal growth restriction pregnancies

INTRODUCTION

The human placenta has a defined lifespan and placental aging is a key feature as pregnancy progresses. Placental aging and mitochondrial dysfunction are known to play a key role in pregnancy pathophysiology. Premature aging of the placenta has also been linked with placental dysfunction resulting in poor fetal development and premature birth.

METHODS

The expression of key mitochondrial-related genes were analysed in a series of publicly available databases then expression changes were validated in placental samples collected from term, pre-term, post-term pregnancies and pregnancies complicated by fetal growth restriction (FGR). Gene and protein expression levels of MFN1, MFN2, TFAM, TOMM20, OPA3 and SIRT4 were measured in placental tissues via qPCR and western blotting.

RESULTS

Initial analysis found that key mitochondrial transcripts related to biogenesis, bioenergetics and mitophagy clustered by pregnancy trimester. A refined list of 13 mitochondrial-related genes were investigated in additional external datasets of pregnancy complications. In the new cohort, protein expression of MFN1 was decreased in FGR and MFN2 is decreased in post-term placenta. Analysis of placental tissues revealed that TOMM20 gene and protein expression was altered in FGR and post-term placenta.

DISCUSSION

MFN1 and MFN2 play a major role in mitochondrial dynamics, and alterations in these markers have been highlighted in early unexplained miscarriage. TOMM20 is an importer protein that plays a major role in mitophagy and changes have also been identified in age-related diseases. Significant changes in MFN1, MFN2 and TOMM20 indicate that mitochondrial regulators play a critical role in placental aging and placental pathophysiology.

Primary and radiation induced skull base osteosarcoma: a systematic review of clinical features and treatment outcomes

PURPOSE

We aim to systematically review and summarize the demographics, clinical features, management strategies, and clinical outcomes of primary and radiation-induced skull-base osteosarcoma (SBO).

METHODS

PubMed, Scopus, and Cochrane databases were used to identify relevant articles. Papers including SBO cases and sufficient clinical outcome data were included. A comprehensive clinical characteristic review and survival analysis were also conducted.

RESULTS

Forty-one studies describing 67 patients were included. The median age was 31 years (male = 59.7%). The middle skull-base was most commonly involved (52.7%), followed by anterior (34.5%) and posterior (12.7%) skull-base. Headache (27%), exophthalmos (18%), and diplopia (10%) were common presenting symptoms. Sixty-eight percent of patients had primary SBO, while 25% had radiation-induced SBO. Surgery was the main treatment modality in 89% of cases. Chemotherapy was administered in 65.7% and radiotherapy in 50%. Median progression-free survival (PFS) was 12 months, and the overall 5-year survival was 22%. The five-year survival rates of radiation-induced SBO and primary SBO were 39% and 16%, respectively (P < 0.05).

CONCLUSION

SBO is a malignant disease with poor survival outcomes. Surgical resection is the primary management modality, in conjunction with chemotherapy and radiotherapy. Radiation-induced SBO has a superior survival outcome as compared to its primary counterpart. Complete surgical resection showed a statistically insignificant survival benefit as compared to partial resection.

Radiation-Induced Immunity and Toxicities: The Versatility of the cGAS-STING Pathway

In the past decade, radiation therapy (RT) entered the era of personalized medicine, following the striking improvements in radiation delivery and treatment planning optimization, and in the understanding of the cancer response, including the immunological response. The next challenge is to identify the optimal radiation regimen(s) to induce a clinically relevant anti-tumor immunity response. Organs at risks and the tumor microenvironment (e.g. endothelial cells, macrophages and fibroblasts) often limit the radiation regimen effects due to adverse toxicities. Here, we reviewed how RT can modulate the immune response involved in the tumor control and side effects associated with inflammatory processes. Moreover, we discussed the versatile roles of tumor microenvironment components during RT, how the innate immune sensing of RT-induced genotoxicity, through the cGAS-STING pathway, might link the anti-tumor immune response, radiation-induced necrosis and radiation-induced fibrosis, and how a better understanding of the switch between favorable and deleterious events might help to define innovative approaches to increase RT benefits in patients with cancer.

[A Review of Celluar Senescence and Tumor Treatment]

Cellular senescence is a permanent state of cell cycle arrest, combined with the acquisition of a variety of secretory phenotypes. In addition to apoptosis, the induction of cellular senescence is an important mechanism that chemo- and radiotherapies and some targeted therapies rely on to produce an anti-tumor effect. However, being a self-protective mechanism of cells, cellular senescence can produce both positive and negative effects in tumor treatment. It remains a challenge to effectively utilize the anti-tumor effect of cellular senescence while averting the pro-tumor effect. How to improve the sensitivity of tumor treatment and to prevent tumor recurrence and metastasis has become the bottleneck in cellular senescence research. We summarize in this review the "double-edged-sword" effect of cellular senescence in tumor treatment. We summarize and discuss the cell autonomous and non-autonomous mechanisms that senescent cells use to affect tumor treatment, hoping to provide information that will help improve the outcome of tumor treatment and promote further research in basic and clinical application of cellular senescence in tumor treatment.

Evidence for a non-stochastic two-field hypothesis for persistent skin cancer risk

With recurring carcinogen exposures, individual tumors develop in a field of genetic mutations through a stepwise process of clonal expansion and evolution. Once established, this “cancer field” persists in the absence of continued carcinogen exposures, resulting in a sustained risk for cancer development. Using a bioimaging approach, we previously demonstrated that a dermal premalignant field characterized by inflammatory angiogenesis persists following the cessation of ultraviolet light exposures and accurately predicts future overlying epidermal tumor formation. Following ultraviolet light treatments, others have observed that patches of p53 immunopositive cells persist stochastically throughout the epidermal stem cell population. However, these studies were done by random biopsies, introducing sampling bias. We now show that, rather than being randomly distributed, p53⁺ epidermal cells are enriched only in areas overlying this multi-focal dermal field. Moreover, we also show that the dermal field is characterized by a senescent phenotype. We propose that persistence of the overlying epithelial cancerization field in the absence of exogenous carcinogens or promoters requires a two-field composite consisting of a dermal senescent field driving the persistence of the overlying epidermal cancer field. These observations challenge current models that suggest that persistence of cancer risk in the absence of continued carcinogen exposures is simply a function of stochastically arranged, long-lived but dormant epithelial clonal stem cells mutants. The model proposed here could provide new insights into how cancer risk persists following cessation of carcinogenic exposures.

Senescence and castration resistance in prostate cancer: A review of experimental evidence and clinical implications

The development of Castration-Resistant Prostate Cancer (CRPC) remains a major challenge in the treatment of this disease. While Androgen Deprivation Therapy (ADT) can result in tumor shrinkage, a primary response of Prostate Cancer (PCa) cells to ADT is a senescent growth arrest. As a response to cancer therapies, senescence has often been considered as a beneficial outcome due to its association with stable growth abrogation, as well as the potential for immune system activation via the Senescence-Associated Secretory Phenotype (SASP). However, there is increasing evidence that not only can senescent cells regain proliferative capacity, but that senescence contributes to deleterious effects of cancer chemotherapy, including disease recurrence. Notably, the preponderance of work investigating the consequences of therapy-induced senescence on tumor progression has been performed in non-PCa models. Here, we summarize the evidence that ADT promotes a senescent response in PCa and postulate mechanisms by which senescence may contribute to the development of castration-resistance. Primarily, we suggest that ADT-induced senescence may support CRPC development via escape from senescence, by cell autonomous-reprogramming, and by the formation of a pro-tumorigenic SASP. However, due to the scarcity of direct evidence from PCa models, the consequences of ADT-induced senescence outlined here remain speculative until the relationship between senescence and CRPC can be experimentally defined.

Senescence in the Development and Response to Cancer with Immunotherapy: A Double-Edged Sword

Cellular senescence was first described as a physiological tumor cell suppressor mechanism that leads to cell growth arrest with production of the senescence-associated secretory phenotype known as SASP. The main role of SASP in physiological conditions is to attract immune cells to clear senescent cells avoiding tumor development. However, senescence can be damage-associated and, depending on the nature of these stimuli, additional types of senescence have been described. In the context of cancer, damage-associated senescence has been described as a consequence of chemotherapy treatments that were initially thought of as a tumor suppressor mechanism. However, in certain contexts, senescence after chemotherapy can promote cancer progression, especially when immune cells become senescent and cannot clear senescent tumor cells. Moreover, aging itself leads to continuous inflammaging and immunosenescence which are responsible for rewiring immune cells to become defective in their functionality. Here, we define different types of senescence, pathways that activate them, and functions of SASP in these events. Additionally, we describe the role of senescence in cancer and its treatments, including how aging and chemotherapy contribute to senescence in tumor cells, before focusing on immune cell senescence and its role in cancer. Finally, we discuss potential therapeutic interventions to reverse cell senescence.

Sex differences in cancer mechanisms

We now know that cancer is many different diseases, with great variation even within a single histological subtype. With the current emphasis on developing personalized approaches to cancer treatment, it is astonishing that we have not yet systematically incorporated the biology of sex differences into our paradigms for laboratory and clinical cancer research. While some sex differences in cancer arise through the actions of circulating sex hormones, other sex differences are independent of estrogen, testosterone, or progesterone levels. Instead, these differences are the result of sexual differentiation, a process that involves genetic and epigenetic mechanisms, in addition to acute sex hormone actions. Sexual differentiation begins with fertilization and continues beyond menopause. It affects virtually every body system, resulting in marked sex differences in such areas as growth, lifespan, metabolism, and immunity, all of which can impact on cancer progression, treatment response, and survival. These organismal level differences have correlates at the cellular level, and thus, males and females can fundamentally differ in their protections and vulnerabilities to cancer, from cellular transformation through all stages of progression, spread, and response to treatment. Our goal in this review is to cover some of the robust sex differences that exist in core cancer pathways and to make the case for inclusion of sex as a biological variable in all laboratory and clinical cancer research. We finish with a discussion of lab- and clinic-based experimental design that should be used when testing whether sex matters and the appropriate statistical models to apply in data analysis for rigorous evaluations of potential sex effects. It is our goal to facilitate the evaluation of sex differences in cancer in order to improve outcomes for all patients.

Infiltrating Myeloid Cells Drive Osteosarcoma Progression via GRM4 Regulation of IL23

The glutamate metabotropic receptor 4 (GRM4) locus is linked to susceptibility to human osteosarcoma, through unknown mechanisms. We show that Grm4^-/- gene-targeted mice demonstrate accelerated radiation-induced tumor development to an extent comparable with Rb1^+/- mice. GRM4 is expressed in myeloid cells, selectively regulating expression of IL23 and the related cytokine IL12. Osteosarcoma-conditioned media induce myeloid cell Il23 expression in a GRM4-dependent fashion, while suppressing the related cytokine Il12. Both human and mouse osteosarcomas express an increased IL23:IL12 ratio, whereas higher IL23 expression is associated with worse survival in humans. Consistent with an oncogenic role, Il23 ^-/- mice are strikingly resistant to osteosarcoma development. Agonists of GRM4 or a neutralizing antibody to IL23 suppressed osteosarcoma growth in mice. These findings identify a novel, druggable myeloid suppressor pathway linking GRM4 to the proinflammatory IL23/IL12 axis. SIGNIFICANCE: Few novel systemic therapies targeting osteosarcoma have emerged in the last four decades. Using insights gained from a genome-wide association study and mouse modeling, we show that GRM4 plays a role in driving osteosarcoma via a non-cell-autonomous mechanism regulating IL23, opening new avenues for therapeutic intervention.See related commentary by Jones, p. 1484.This article is highlighted in the In This Issue feature, p. 1469.

Unmasking senescence: context-dependent effects of SASP in cancer

Cellular senescence plays a critical role in tumorigenesis. Once thought of as a tissue culture artefact by some researchers, senescence is now a major field of study. Although there are common molecular mechanisms that enforce the growth arrest that characterizes the phenotype, the impact of senescence is varied and can, in some instances, have opposite effects on tumorigenesis. It has become clearer that the cell of origin and the tissue in question dictate the impact of senescence on tumorigenesis. In this Review, we unravel this complexity by focusing on how senescence impacts tumorigenesis when it arises within incipient tumour cells versus stromal cells, and how these roles can change in different stages of disease progression. In addition, we highlight the diversity of the senescent phenotype and its functional output beyond growth arrest: the senescence-associated secretory phenotype (SASP). Fortunately, a number of new genetic and pharmacologic tools have been developed that are now allowing the senescence phenotype to be parsed further.

Replication and discovery of musculoskeletal QTLs in LG/J and SM/J advanced intercross lines

The genetics underlying variation in health‐related musculoskeletal phenotypes can be investigated in a mouse model. Quantitative trait loci (QTLs) affecting musculoskeletal traits in the LG/J and SM/J strain lineage remain to be refined and corroborated. The aim of this study was to map muscle and bone traits in males (n = 506) of the 50th filial generation of advanced intercross lines (LG/SM AIL) derived from the two strains. Genetic contribution to variation in all musculoskeletal traits was confirmed; the SNP heritability of muscle mass ranged between 0.46 and 0.56; and the SNP heritability of tibia length was 0.40. We used two analytical software, GEMMA and QTLRel, to map the underlying QTLs. GEMMA required substantially less computation and recovered all the QTLs identified by QTLRel. Seven significant QTLs were identified for muscle weight (Chr 1, 7, 11, 12, 13, 15, and 16), and two for tibia length, (Chr 1 and 13). Each QTL explained 4–5% of phenotypic variation. One muscle and both bone loci replicated previous findings; the remaining six were novel. Positional candidates for the replicated QTLs were prioritized based on in silico analyses and gene expression in muscle tissue. In summary, we replicated existing QTLs and identified novel QTLs affecting muscle weight, and replicated bone length QTLs in LG/SM AIL males. Heritability estimates substantially exceed the cumulative effect of the QTLs, hence a richer genetic architecture contributing to muscle and bone variability could be uncovered with a larger sample size.

Pro- and anti-tumorigenic functions of the senescence-associated secretory phenotype

Introduction: Cellular senescence is a stable form of cell cycle exit. Though they no longer divide, senescent cells remain metabolically active and secrete a plethora of proteins collectively termed the senescence-associated secretory phenotype (SASP). Although senescence-associated cell cycle exit likely evolved as an anti-tumor mechanism, the SASP contains both anti- and pro-tumorigenic potential.Areas covered: In this review, we briefly discuss the discovery of senescent cells and its relationship to cancer and aging. We also describe the initiation and regulation of the SASP upon senescence stimulus onset. We focus on both the pro- and anti-tumorigenic properties of the SASP. Finally, we speculate on the potential benefits of therapy-induced senescence combined with selective SASP inhibition for the treatment of cancer.Expert opinion: Further identification and characterization of the SASP factors that are pro-tumorigenic and those that are anti-tumorigenic in specific contexts will be crucial in order to develop personalized therapeutics for the successful treatment of cancer.

Radiation-Induced Sarcoma of the Head and Neck: A Review of the Literature

In the last decades, radiotherapy (RT) has become one of the cornerstones in the treatment of head and neck (HN) malignancies and has paralleled an increase in long-term patient survival. This lead to a concomitant increase in the incidence of radiation-induced sarcomas (RIS) of the irradiated field, with an annual rate up to 0.17%. The new techniques of irradiation do not seem to influence the risk of RIS of the HN (RISHN), which mainly develop within the middle-dose field. The median latency of RISHN after RT is 10–12 years and osteosarcoma is the most represented histotype, even though there is a high variability in time of occurrence and histological features observed. There is no clear evidence of predisposing factors for RISHN, and genetic findings so far have not revealed any common mutation. Early clinical diagnosis of RISHN is challenging, since it usually occurs within fibrotic and hardened tissues, while radiological findings are not pathognomonic and able to differentiate them from other neoplastic entities. Given the highly aggressive behavior of RISHN and its poor sensitivity to chemotherapy, radical surgery is the most important prognostic factor and the only curative option at present. Nevertheless, the anatomy of the HN district and the infiltrative nature of RIS do not always allow radical intervention. Therefore, a wise integration with systemic therapy and, when feasible, re-irradiation should be performed. Future findings in the genomic features of RISHN will be crucial to identify a possible sensitivity to specific drugs in order to optimize a multimodal treatment that will be ideally complementary to surgery and re-irradiation.

dNTP metabolism links mechanical cues and YAP/TAZ to cell growth and oncogene-induced senescence

YAP/TAZ, downstream transducers of the Hippo pathway, are powerful regulators of cancer growth. How these factors control proliferation remains poorly defined. Here, we found that YAP/TAZ directly regulate expression of key enzymes involved in deoxynucleotide biosynthesis and maintain dNTP precursor pools in human cancer cells. Regulation of deoxynucleotide metabolism is required for YAP-induced cell growth and underlies the resistance of YAP-addicted cells to chemotherapeutics targeting dNTP synthesis. During RAS-induced senescence, YAP/TAZ bypass RAS-mediated inhibition of nucleotide metabolism and control senescence. Endogenous YAP/TAZ targets and signatures are inhibited by RAS/MEK1 during senescence, and depletion of YAP/TAZ is sufficient to cause senescence-associated phenotypes, suggesting a role for YAP/TAZ in suppression of senescence. Finally, mechanical cues, such as ECM stiffness and cell geometry, regulate senescence in a YAP-dependent manner. This study indicates that YAP/TAZ couples cell proliferation with a metabolism suited for DNA replication and facilitates escape from oncogene-induced senescence. We speculate that this activity might be relevant during the initial phases of tumour progression or during experimental stem cell reprogramming induced by YAP.

Knockdown of pyruvate kinase type M2 suppresses tumor survival and invasion in osteosarcoma cells both in vitro and in vivo

Osteosarcoma (OS) is the mostly diagnosed primary bone malignancy. Emerging evidence indicates that the activity of pyruvate kinase M2 (PKM2) isoform is crucial for the survival of tumor cells. In the present study, the effect of PKM2 knockdown on the proliferation and migration of OS cells were assessed both in vitro and in vivo. Small hairpin RNA (shRNA) technology were employed to suppress the expression of PKM2 in MG-63 and Saos-2 cell lines. In vitro, shRNA-mediated knockdown of PKM2 efficiently inhibited cell proliferation, and induced G1 cell cycle arrest and apoptosis in both cell lines, which was associated with decreased expressions of cyclin D1 and Bcl-2 as well as increased expressions of Bax, cleaved-caspase-3, and cleaved-PARP. The invasion and migration potential of OS cell lines were also inhibited by PKM2 knockdown through the regulating effect of PKM2 on MMP-2 and VEGF signaling. In vivo, knockdown of PKM2 decelerated tumor growth rate and induced structure deterioration in tumor tissues. The current study for the first time showed that the activity of PKM2 was indispensable for the development and metastasis of OS, thereby providing the basic information for the future development of PKM2-based anti-OS therapies.

To clear, or not to clear (senescent cells)? That is the question

Cellular senescence is an anti-proliferative program that restricts the propagation of cells subjected to different kinds of stress. Cellular senescence was initially described as a cell-autonomous tumor suppressor mechanism that triggers an irreversible cell cycle arrest that prevents the proliferation of damaged cells at risk of neoplastic transformation. However, discoveries during the last decade have established that senescent cells can also impact the surrounding tissue microenvironment and the neighboring cells in a non-cell-autonomous manner. These non-cell-autonomous activities are, in part, mediated by the selective secretion of extracellular matrix degrading enzymes, cytokines, chemokines and immune modulators, which collectively constitute the senescence-associated secretory phenotype. One of the key functions of the senescence-associated secretory phenotype is to attract immune cells, which in turn can orchestrate the elimination of senescent cells. Interestingly, the clearance of senescent cells seems to be critical to dictate the net effects of cellular senescence. As a general rule, the successful elimination of senescent cells takes place in processes that are considered beneficial, such as tumor suppression, tissue remodeling and embryonic development, while the chronic accumulation of senescent cells leads to more detrimental consequences, namely, cancer and aging. Nevertheless, exceptions to this rule may exist. Now that cellular senescence is in the spotlight for both anti-cancer and anti-aging therapies, understanding the precise underpinnings of senescent cell removal will be essential to exploit cellular senescence to its full potential.

Molecular genetics of osteosarcoma

Osteosarcoma is the predominant form of bone cancer, affecting mostly adolescents. Recent progress made in molecular genetic studies of osteosarcoma has changed our view on the cause of the disease and ongoing therapeutic approaches for patients. As we draw closer to gaining more complete catalogs of candidate cancer driver genes in common forms of cancer, the landscape of somatic mutations in osteosarcoma is emerging from its first phase. In this review, we summarize recent whole genome and/or whole exome genomic studies, and then put these findings in the context of genetic hallmarks of somatic mutations and mutational processes in human osteosarcoma. One of the lessons learned here is that the extent of somatic mutations and complexity of the osteosarcoma genome are similar to that of common forms of adult cancer. Thus, a much higher number of samples than those currently obtained are needed to complete the catalog of driver mutations in human osteosarcoma. In parallel, genetic studies in other species have revealed candidate driver genes and their roles in the genesis of osteosarcoma. This review also summarizes newly identified drivers in genetically engineered mouse models (GEMMs) and discusses our understanding of the impact of nature and number of drivers on tumor latency, subtypes, and metastatic potentials of osteosarcoma. It is becoming apparent that a synergistic team composed of three drivers (one 'first driver' and two 'synergistic drivers') may be required to generate an animal model that recapitulates aggressive osteosarcoma with a short latency. Finally, new cancer therapies are urgently needed to improve survival rate and quality of life for osteosarcoma patients. Several vulnerabilities in osteosarcoma are illustrated in this review to exemplify the opportunities for next generation molecularly targeted therapies. However, much work remains in order to complete our understanding of the somatic mutation basis of osteosarcoma, to develop reliable animal models of human disease, and to apply this information to guide new therapeutic approaches for reducing morbidity and mortality of this rare disease.

Immune Therapy for Sarcomas

Absolute lymphocyte count (ALC) recovery rapidly occurring at 14 days after start of chemotherapy for osteosarcoma and Ewing sarcoma is a good prognostic factor. Conversely, lymphopenia is associated with significantly decreased sarcoma survival. Clearly, the immune system can contribute towards better survival from sarcoma. This chapter will describe treatment and host factors that influence immune function and how effective local control and systemic interventions of sarcoma therapy can cause inflammation and/or immune suppression but are currently the standard of care. Preclinical and clinical efforts to enhance immune function against sarcoma will be reviewed. Interventions to enhance immune function against sarcoma have included regional therapy (surgery, cryoablation, radiofrequency ablation, electroporation, and radiotherapy), cytokines, macrophage activators (mifamurtide), vaccines, natural killer (NK) cells, T cell receptor (TCR) and chimeric antigen receptor (CAR) T cells, and efforts to decrease inflammation. The latter is particularly important because of new knowledge about factors influencing expression of checkpoint inhibitory molecules, PD1 and CTLA-4, in the tumor microenvironment. Since these molecules can now be blocked using anti-PD1 and anti-CTLA-4 antibodies, how to translate this knowledge into more effective immune therapies in the future as well as how to augment effectiveness of current interventions (e.g., radiotherapy) is a challenge. Barriers to implementing this knowledge include cost of agents that release immune checkpoint blockade and coordination of cost-effective outpatient sarcoma treatment. Information on how to research clinical trial eligibility criteria and how to access current immune therapy trials against sarcoma are shared, too.

Response of mouse thymic cells to radiation after transfusion of mesenchymal stem cells

Thymic lymphoma is a highly invasive and even metastatic cancer. This study investigated the effects of mesenchymal stem cells (MSCs) transfusion on cell cycle, cell proliferation, CD3 expression, mutation frequency of T cell receptor using mouse model of thymic lymphoma.C57BL/6J young mouse models of thymoma were injected with MSCs. Six months later, the thymus was taken for pathological examination and flow cytometry studies. The cells were labeled with anti-CD4, CD8, CD3, propidium iodide, or CFDA-SE, cell cycle, proliferation kinetics, and mutation frequency of T cell receptor, respectively.Pathologic results showed that control had clear corticomedular structure with regularly shaped lymphocytes. After radiation, the thymus structure was completely destroyed, with lymphoid tumor cells diffusely distributed and heavily stained, and large nuclei. Transfusion of MSCs resulted in normal thymus structure. Cytometry studies showed that there were more CD4-/CD8- T cells in the thymus of irradiated mice than in control; transfusion of MSCs led to reduced CD4-/CD8- T cells. In irradiated mice, there were less CD4+/CD8+ T cells than in control and MSCs transfusion groups. It was observed that there were more cells arrested in G1 phase in the thymus cells and CD4-/CD8- T cells in irradiated mice than in other 2 groups, whereas there were more cells arrested in S phase in CD4+/CD8+ and CD4+/CD8- T cells in irradiated mice than in the other mice. In the thymus cells, and CD4+/CD8+ and CD4+/CD8- T cells, irradiated mice group had significantly less parent, G2, G3, and G4 cells, and more cells at higher generations, and also higher proliferation index. In CD4-/CD8- T cells, irradiated mice had significantly more parent, G2, and G3 cells, and less G4, G5, G6, and propidium iodide, as compared with the other 2 groups. The expression of CD3 in CD4/CD8 T cells was significantly higher than in control. MSCs transfusion improved CD3 expression, but was still less than the control. Irradiation resulted in very high mutation frequency of T cell receptor, which was barely affected by MSCs transfusion.Mesenchymal stem cell transfusion is able to restore the cell cycle and cell proliferation, but not CD3 expression and mutation frequency of T cell receptor in irradiated mice to control level.

SASP: Tumor Suppressor or Promoter? Yes!

Cellular senescence is a permanent growth arrest in cells with damage or stress that could lead to transformation. Some tumor cells also undergo senescence in response to chemotherapy. Senescent cells secrete cytokines and other factors of the senescence-associated secretory phenotype (SASP) that contribute to tumor suppression by enforcing arrest and recruiting immune cells that remove these damaged or oncogene-expressing cells from organisms. However, some cells can develop a SASP comprising factors that are immunosuppressive and protumorigenic by paracrine mechanisms. Likewise, the SASP in treated cancers can either contribute to durable responses or drive relapse. Here, we discuss the studies that have demonstrated a complex and often conflicting role for the SASP in tumorigenesis and treatment response.

Present Advances and Future Perspectives of Molecular Targeted Therapy for Osteosarcoma

Osteosarcoma (OS) is a bone cancer mostly occurring in pediatric population. Current treatment regime of surgery and intensive chemotherapy could cure about 60%-75% patients with primary osteosarcoma, however only 15% to 30% can be cured when pulmonary metastasis or relapse has taken place. Hence, novel precise OS-targeting therapies are being developed with the hope of addressing this issue. This review summarizes the current development of molecular mechanisms and targets for osteosarcoma. Therapies that target these mechanisms with updated information on clinical trials are also reviewed. Meanwhile, we further discuss novel therapeutic targets and OS-targeting drug delivery systems. In conclusion, a full insight in OS pathogenesis and OS-targeting strategies would help us explore novel targeted therapies for metastatic osteosarcoma.

Mouse Models of Tumor Immunotherapy

Immunotherapy is now evolving into a major therapeutic option for cancer patients. Such clinical advances also promote massive interest in the search for novel immunotherapy targets, and to understand the mechanism of action of current drugs. It is projected that a series of novel immunotherapy agents will be developed and assessed for their therapeutic activity. In light of this, in vivo experimental mouse models that recapitulate human malignancies serve as valuable tools to validate the efficacy and safety profile of immunotherapy agents, before their transition into clinical trials. In this review, we will discuss the major classes of experimental mouse models of cancer commonly used for immunotherapy assessment and provide examples to guide the selection of appropriate models. We present some new data concerning the utility of a carcinogen-induced tumor model for comparing immunotherapies and combining immunotherapy with chemotherapy. We will also highlight some recent advances in experimental modeling of human malignancies in mice that are leading towards personalized therapy in patients.

Cancer prevention and therapy through the modulation of the tumor microenvironment

Cancer arises in the context of an in vivo tumor microenvironment. This microenvironment is both a cause and consequence of tumorigenesis. Tumor and host cells co-evolve dynamically through indirect and direct cellular interactions, eliciting multiscale effects on many biological programs, including cellular proliferation, growth, and metabolism, as well as angiogenesis and hypoxia and innate and adaptive immunity. Here we highlight specific biological processes that could be exploited as targets for the prevention and therapy of cancer. Specifically, we describe how inhibition of targets such as cholesterol synthesis and metabolites, reactive oxygen species and hypoxia, macrophage activation and conversion, indoleamine 2,3-dioxygenase regulation of dendritic cells, vascular endothelial growth factor regulation of angiogenesis, fibrosis inhibition, endoglin, and Janus kinase signaling emerge as examples of important potential nexuses in the regulation of tumorigenesis and the tumor microenvironment that can be targeted. We have also identified therapeutic agents as approaches, in particular natural products such as berberine, resveratrol, onionin A, epigallocatechin gallate, genistein, curcumin, naringenin, desoxyrhapontigenin, piperine, and zerumbone, that may warrant further investigation to target the tumor microenvironment for the treatment and/or prevention of cancer.

Radiation-Induced Sarcoma: A 15-Year Experience in a Single Large Tertiary Referral Center

Purpose

The purpose of this study is to report on the incidence and the experience in management of radiation-induced sarcoma (RIS) at a large single center in Korea for 15 years.

Materials and Methods

We retrospectively reviewed the sarcoma registry of a large institution from January 2000 to April 2014.

Results

Out of the 3,674 patients listed in the registry, 33 patients (0.9%) diagnosed with RIS were identified. The median latency of RIS was 12.1 years. The number of cases of RIS increased from four cases in the years 2000-2003 to 14 cases in the years 2012-2014. The most common histology was osteosarcoma (36.4%). The median follow-up period was 23.1 months, the median overall survival (OS) of all patients was 2.9 years, and their 5-year survival rate was 44.7%. Univariate and multivariate analyses showed association of the age at diagnosis (p=0.01) and the treatment aim (p=0.001) with the OS. The median OS and the 5-year survival rate of patients treated with curative surgery (n=19) were 9.6 years and 65%, respectively, and of the conservatively treated patients, 0.7 years and 0% (n=14). Re-irradiation was delivered to nine patients, and radiation toxicity was observed in five patients.

Conclusion

In this study, RIS accounted for 0.9% of the cases of sarcoma, with increasing incidence. Despite the association of curative resection with increased survival, it could be applied to only 58% of the patients. Considering the limited treatment options for RIS, conduct of a genetic study to identify the underlying mechanism of RIS is needed.

Bone microenvironment signals in osteosarcoma development

The bone is a complex connective tissue composed of many different cell types such as osteoblasts, osteoclasts, chondrocytes, mesenchymal stem/progenitor cells, hematopoietic cells and endothelial cells, among others. The interaction between them is finely balanced through the processes of bone formation and bone remodeling, which regulates the production and biological activity of many soluble factors and extracellular matrix components needed to maintain the bone homeostasis in terms of cell proliferation, differentiation and apoptosis. Osteosarcoma (OS) emerges in this complex environment as a result of poorly defined oncogenic events arising in osteogenic lineage precursors. Increasing evidence supports that similar to normal development, the bone microenvironment (BME) underlies OS initiation and progression. Here, we recapitulate the physiological processes that regulate bone homeostasis and review the current knowledge about how OS cells and BME communicate and interact, describing how these interactions affect OS cell growth, metastasis, cancer stem cell fate and therapy outcome.

Opportunities and challenges of radiotherapy for treating cancer

The past 20 years have seen dramatic changes in the delivery of radiation therapy, but the impact of radiobiology on the clinic has been far less substantial. A major consideration in the use of radiotherapy has been on how best to exploit differences between the tumour and host tissue characteristics, which in the past has been achieved empirically by radiation-dose fractionation. New advances are uncovering some of the mechanistic processes that underlie this success story. In this Review, we focus on how these processes might be targeted to improve the outcome of radiotherapy at the individual patient level. This approach would seem a more productive avenue of treatment than simply trying to increase the radiation dose delivered to the tumour.

The Effect of OSM on MC3T3-E1 Osteoblastic Cells in Simulated Microgravity with Radiation

Bone deterioration is a challenge in long-term spaceflight with significant connections to patients experiencing disuse bone loss. Prolonged unloading and radiation exposure, defining characteristics of space travel, have both been associated with changes in inflammatory signaling via IL-6 class cytokines in bone. While there is also evidence for perturbed IL-6 class signaling in spaceflight, there has been scant examination of the connections between microgravity, radiation, and inflammatory stimuli in bone. Our lab and others have shown that the IL-6 class cytokine oncostatin M (OSM) is an important regulator of bone remodeling. We hypothesize that simulated microgravity alters osteoblast OSM signaling, contributing to the decoupling of osteolysis and osteogenesis in bone homeostasis. To test this hypothesis, we induced OSM signaling in murine MC3T3-E1 pre-osteoblast cells cultured in modeled microgravity using a rotating wall vessel bioreactor with and without exposure to radiation typical of a solar particle event. We measured effects on inflammatory signaling, osteoblast activity, and mineralization. Results indicated time dependent interactions among all conditions in the regulation of IL-6 production. Furthermore, OSM induced the transcription of OSM receptor ß, IL 6 receptor α subunits, collagen α1(I), osteocalcin, sclerostin, RANKL, and osteoprotegerin. Measurements of osteoid mineralization suggest that the spatial organization of the osteoblast environment is an important consideration in understanding bone formation. Taken together, these results support a role for altered OSM signaling in the mechanism of microgravity-induced bone loss.

Expression and clinical significance of cyclooxygenase-2 and microRNA-143 in osteosarcoma

The aim of the present study was to investigate the expression profiles of cyclooxygenase (COX)-2 and microRNA (miRNA)-143 in the tumor tissue and blood samples of patients with osteosarcoma, and their involvement in the disease pathogenesis. Tumor tissue and blood samples were obtained from 46 patients with osteosarcoma (stages I-III). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analyses were performed to detect the mRNA and protein expression of COX-2, respectively, in these samples. The expression of miRNA-143 in the tumor tissue and blood samples was assessed using RT-qPCR. The results showed that, compared with the normal control subjects, the mRNA and protein expression levels of COX-2 in the tumor tissue and blood samples of patients with osteosarcoma were increased. Among the patients with osteosarcoma, increases in the COX-2 mRNA and protein levels were observed with progressing disease severity (from stage I to stage III), suggesting the involvement of COX-2 in the disease pathogenesis. By contrast, the expression of miRNA-143 decreased as the disease progressed, which was the opposite trend to the COX-2 expression, indicating that miRNA-143 and COX-2 may play different roles in the disease pathogenesis. In conclusion, COX-2 expression in the tumor tissue and blood samples of patients with osteosarcoma increases significantly along with the degree of tumor malignancy, and this is accompanied by a decreased expression of miRNA-143; therefore, a negative correlation between COX-2 and miRNA-143 may exist in the progression of osteosarcoma.

Age-associated inflammation connects RAS-induced senescence to stem cell dysfunction and epidermal malignancy

Aging is the single biggest risk factor for malignant transformation. Among the most common age-associated malignancies are non-melanoma skin cancers, comprising the most common types of human cancer. Here we show that mutant H-Ras activation in mouse epidermis, a frequent event in cutaneous squamous cell carcinoma (SCC), elicits a differential outcome in aged versus young mice. Whereas H-Ras activation in the young skin results in hyperplasia that is mainly accompanied by rapid hair growth, H-Ras activation in the aged skin results in more dysplasia and gradual progression to in situ SCC. Progression is associated with increased inflammation, pronounced accumulation of immune cells including T cells, macrophages and mast cells as well as excessive cell senescence. We found not only an age-dependent increase in expression of several pro-inflammatory mediators, but also activation of a strong anti-inflammatory response involving enhanced IL4/IL10 expression and immune skewing toward a Th2 response. In addition, we observed an age-dependent increase in the expression of Pdl1, encoding an immune suppressive ligand that promotes cancer immune evasion. Moreover, upon switching off oncogenic H-Ras activity, young but not aged skin regenerates successfully, suggesting a failure of the aged epidermal stem cells to repair damaged tissue. Our findings support an age-dependent link between accumulation of senescent cells, immune infiltration and cancer progression, which may contribute to the increased cancer risk associated with old age.

Translational biology of osteosarcoma

For the past 30 years, improvements in the survival of patients with osteosarcoma have been mostly incremental. Despite evidence of genomic instability and a high frequency of chromothripsis and kataegis, osteosarcomas carry few recurrent targetable mutations, and trials of targeted agents have been generally disappointing. Bone has a highly specialized immune environment and many immune signalling pathways are important in bone homeostasis. The success of the innate immune stimulant mifamurtide in the adjuvant treatment of non-metastatic osteosarcoma suggests that newer immune-based treatments, such as immune checkpoint inhibitors, may substantially improve disease outcome.