Clinical development of new drug-radiotherapy combinations

Genotype-Directed Synthetic Cytotoxicity of ATR Inhibition with Radiotherapy

PURPOSE

The importance of the DNA damage response in mediating effects of radiotherapy (RT) has galvanized efforts to target this pathway with radiosensitizers. Yet early clinical trials of this approach have failed to yield a benefit in unselected populations. We hypothesized that ataxia-telangiectasia mutated (Atm)-null tumors would demonstrate genotype-specific synergy between RT and an inhibitor of the DNA damage response protein ataxia-telangiectasia and Rad3-related (ATR) kinase.

EXPERIMENTAL DESIGN

We investigated the synergistic potential of the ATR inhibitor (ATRi) RP-3500 and RT in two Atm-null and isogenic murine models, both in vitro and in vivo. Staining of γ-H2AX foci, characterization of the immune response via flow cytometry, and tumor rechallenge experiments were performed to elucidate the mechanism of interaction. To examine genotype specificity, we tested the interaction of ATRi and RT in a Brca1-null model. Finally, patients with advanced cancer with ATM alterations were enrolled in a phase I/II clinical trial to validate preclinical findings.

RESULTS

Synergy between RP-3500 and RT was confirmed in Atm-null lines in vitro, characterized by an accumulation of DNA double-strand breaks. In vivo, Atm-null tumor models had higher rates of durable control with RT and ATRi than controls. In contrast, there was no synergy in tumors lacking Brca1. Analysis of the immunologic response indicated that efficacy is largely mediated by cell-intrinsic mechanisms. Lastly, early results from our clinical trial showed complete responses in patients.

CONCLUSIONS

Genotype-directed radiosensitization with ATRi and RT can unleash significant therapeutic benefit and could represent a novel approach to develop more effective combinatorial synthetic cytotoxic RT-based treatments. See related commentary by Schrank and Colbert, p. 5505.

Exosomes as carriers to stimulate an anti-cancer immune response in immunotherapy and as predictive markers

During this era of rapid advancements in cancer immunotherapy, the application of cell-released small vesicles that activate the immune system is of considerable interest. Exosomes are cell-derived nanovesicles that show great promise for the immunological treatment of cancer because of their immunogenicity and molecular transfer capacity. Recent technological advancements have enabled the identification of functional functions that exosome cargoes perform in controlling immune responses. Exosomes are originated specifically from immune cells and tumor cells and they show unique composition patterns directly related to the immunotherapy against cancer. Exosomes can also deliver their cargo to particular cells, which can affect the phenotypic and immune-regulatory functions of those cells. Exosomes can influence the course of cancer and have therapeutic benefits by taking part in several cellular processes; as a result, they have the dual properties of activating and restraining cancer. Exosomes have tremendous potential for cancer immunotherapy; they may develop into the most powerful cancer vaccines and carriers of targeted antigens and drugs. Comprehending the potential applications of exosomes in immune therapy is significant for regulating cancer progression. This review offers an analysis of the function of exosomes in immunotherapy, specifically as carriers that function as diagnostic indicators for immunological activation and trigger an anti-cancer immune response. Moreover, it summarizes the fundamental mechanism and possible therapeutic applications of exosome-based immunotherapy for human cancer.

Current situation and trends of radiation therapy in Japan based on the National Database Open Data

This study aimed to visualize the current situation and trends in radiation therapy in Japan using open data from the Japanese National Database of Health Insurance Claims and Specific Health Checkups (NDB). We downloaded the NDB open data from the website of Japan's Ministry of Health, Labor and Welfare and used Python libraries to analyze the receipt data related to radiation therapy from fiscal year 2014 to 2022. The number of radiation therapy plans peaked in 2019, temporarily declined and subsequently showed a gradual increase. Conversely, the total points associated with radiation therapy have consistently increased without any decline. The use of high-precision radiation therapies such as intensity-modulated radiation therapy (IMRT) has increased over time. Significant regional differences exist, with the Chubu and Kyushu regions showing higher total points and receipts per certified radiation oncologist. A correlation was observed between the number of IMRT plans per population and the number of certified radiation oncologists. Males exhibited a sharp peak in their early 70s, while females demonstrated a mild peak from their 40s to 80s. In recent years, the points for males in their early 70s have rapidly increased. We used the NDB open data to illustrate the current situation and trends in radiation therapy in Japan, highlighting reduced costs and workloads. This study underscored the regional differences in radiation therapy and emphasized the need to discuss strategies for meeting future demand.

Combating tumor PARP inhibitor resistance: Combination treatments, nanotechnology, and other potential strategies

PARP (poly (ADP-ribose) polymerase) inhibitors (PARPi) have demonstrated significant potential in cancer treatment, particularly in tumors with breast cancer susceptibility gene (BRCA) mutations and other DNA repair deficiencies. However, the development of resistance to PARPi has become a major challenge in their clinical application. The emergence of drug resistance leads to reduced efficacy of the PARPi over time, impacting long-term treatment outcomes and survival rates. PARPi resistance in tumors often arises as cells activate alternative DNA repair pathways or evade the effect of PARPi, diminishing therapeutic effectiveness. Consequently, overcoming resistance is crucial for maintaining treatment efficacy and improving patient prognosis. This paper reviews the strategies to overcome PARPi resistance through combination treatment and nanotechnology therapy. We first review the current combination therapies with PARPi, including anti-angiogenic therapies, radiotherapies, immunotherapies, and chemotherapies, and elucidate their mechanisms for overcoming PARPi resistance. Additionally, this paper focuses on the application of nanotechnology in improving the effectiveness of PARPi and overcoming drug resistance. Subsequently, this paper presents several promising strategies to tackle PARPi resistance, including but not limited to: structural modifications of PARPi, deployment of gene editing systems, implementation of "membrane lipid therapy," and modulation of cellular metabolism in tumors. By integrating these strategies, this research will provide comprehensive approaches to overcome the resistance of PARPi in cancer treatment and offer guidance for future research and clinical practice.

Nano- and Micro-Platforms in Therapeutic Proteins Delivery for Cancer Therapy: Materials and Strategies

Proteins have emerged as promising therapeutics in oncology due to their great specificity. Many treatment strategies are developed based on protein biologics, such as immunotherapy, starvation therapy, and pro-apoptosis therapy, while some protein biologics have entered the clinics. However, clinical translation is severely impeded by instability, short circulation time, poor transmembrane transportation, and immunogenicity. Micro- and nano-particles-based drug delivery platforms are designed to solve those problems and enhance protein therapeutic efficacy. This review first summarizes the different types of therapeutic proteins in clinical and research stages, highlighting their administration limitations. Next, various types of micro- and nano-particles are described to demonstrate how they can overcome those limitations. The potential of micro- and nano-particles are then explored to enhance the therapeutic efficacy of proteins by combinational therapies. Finally, the challenges and future directions of protein biologics carriers are discussed for optimized protein delivery.

Immune effects of α and β radionuclides in metastatic prostate cancer

External beam radiotherapy is used for radical treatment of organ-confined prostate cancer and to treat lesions in metastatic disease whereas molecular radiotherapy with labelled prostate-specific membrane antigen ligands and radium-223 (223Ra) is indicated for metastatic prostate cancer and has demonstrated substantial improvements in symptom control and overall survival compared with standard-of-care treatment. Prostate cancer is considered an immunologically cold tumour, so limited studies investigating the treatment-induced effects on the immune response have been completed. However, emerging data support the idea that radiotherapy induces an immune response in prostate cancer, but whether the response is an antitumour or pro-tumour response is dependent on the radiotherapy regime and is also cell-line dependent. In vitro data demonstrate that single-dose radiotherapy regimes induce a greater immune-suppressive profile than fractionated regimes; less is known about the immune response induced by molecular radiotherapy agents, but evidence suggests that these agents might induce an immune-suppressive systemic immune response, indicated by increased expression of inhibitory checkpoint molecules such as programmed cell death 1 ligand 1 and 2, and that these changes could be associated with clinical response. Different radiotherapy modalities can induce distinct immune profiles, which can either activate or suppress immune-mediated tumour killing and the current preclinical models used for prostate cancer research are not yet optimal for studying the complexity of the radiotherapy-induced immune response.

The potential characteristics of the sense of coherence in cancer radiotherapy patients and its correlation with coping strategies

OBJECTIVE

To explore the potential profiles of the sense of coherence (SOC) among cancer radiotherapy patients using latent profile analysis (LPA) and to characterize each category. Additionally, we investigated the correlation between different profiles of the SOC and the coping strategies.

METHODS

Convenience sampling method was used to select 241 cancer radiotherapy patients hospitalized in a specialized hospital in Shanghai from March 2023 to October 2023 as research subjects. The study utilized a general information questionnaire, the Sense of Coherence Scale-13 (SOC-13), and the Medical Coping Modes Questionnaire (MCMQ) for the survey.

RESULTS

LPA identified three potential profiles based on varying levels of SOC: "Low level-High meaningfulness" group (n = 38, 15.8%), "Moderate level-High manageability" group (n = 104, 43.2%), and "High level-Balanced" group (n = 99, 41%). Age (OR = 6.544, P = 0.015), residence (OR = 0.217, P = 0.004), initial recurrence (OR = 2.869, P = 0.028), and side effects (OR = 2.862, P = 0.015) were significant predictors. A lower level of the SOC was significantly associated with higher scores in acceptance-resignation (P < 0.001).

CONCLUSION

The SOC among cancer radiotherapy patients can be divided into three potential profiles. Younger patients with side effect have lower levels of the SOC. Adopting a acceptance-resignation coping strategies is related to a lower SOC, suggesting that enhancing the level of the SOC plays a positive role in helping patients cope with stressful events.

Best practices and novel approaches for the preclinical development of drug-radiotherapy combinations for cancer treatment

Drug-radiation combination therapy is a practical approach to improving clinical outcomes for many tumours. Unfortunately, most clinical combination studies combine drugs with radiotherapy empirically and do not exploit mechanistic synergy in cell death and the interconnectivity of molecular pathways of tumours or rationale for selecting the dose, fractionation, and schedule, which can result in suboptimal efficacy and exacerbation of toxic effects. However, opportunities exist to generate compelling preclinical evidence for combination therapies from fit-for-purpose translational studies for simulating the intended clinical study use scenarios with standardised preclinical assays and algorithms to evaluate complex molecular interactions and analysis of synergy before clinical research. Here, we analyse and discuss the core issues in the translation of preclinical data to enhance the relevance of preclinical assays, in vitro clonogenic survival along with apoptosis, in vivo tumour regression and growth delay assays, and toxicology of organs at risk without creating barriers to innovation and provide a synopsis of emerging areas in preclinical radiobiology.

Challenges and opportunities for early phase clinical trials of novel drug-radiotherapy combinations: recommendations from NRG Oncology, the American Society for Radiation Oncology (ASTRO), the American College of Radiology (ACR), the Sarah Cannon Research Institute, and the American College of Radiation Oncology (ACRO)

NRG Oncology's Developmental Therapeutics and Radiation Therapy Subcommittee assembled an interdisciplinary group of investigators to address barriers to successful early phase clinical trials of novel combination therapies involving radiation. This Policy Review elucidates some of the many challenges associated with study design for early phase trials combining radiotherapy with novel systemic agents, which are distinct from drug-drug combination development and are often overlooked. We also advocate for potential solutions that could mitigate or eliminate some of these barriers, providing examples of specific clinical trial designs that could help facilitate efficient and effective evaluation of novel drug-radiotherapy combinations.

Immunological signatures from irradiated cancer-associated fibroblasts

Introduction

Cancer-associated fibroblasts (CAFs) are abundant and influential elements of the tumor microenvironment (TME), giving support to tumor development in multiple ways. Among other mechanisms, CAFs are important regulators of immunological processes occurring in tumors. However, CAF-mediated tumor immunomodulation in the context of radiotherapy remains poorly understood. In this study, we explore effects of radiation on CAF-derived immunoregulatory signals to the TME.

Methods

Primary CAF cultures were established from freshly collected human NSCLC lung tumors. CAFs were exposed to single-high or fractionated radiation regimens (1x18Gy or 3x6Gy), and the expression of different immunoregulatory cell-associated and secreted signaling molecules was analyzed 48h and 6 days after initiation of treatment. Analyses included quantitative measurements of released damage-associated molecular patterns (DAMPs), interferon (IFN) type I responses, expression of immune regulatory receptors, and secretion of soluble cytokines, chemokines, and growth factors. CAFs are able to survive ablative radiation regimens, however they enter into a stage of premature cell senescence.

Results

Our data show that CAFs avoid apoptosis and do not contribute by release of DAMPs or IFN-I secretion to radiation-mediated tumor immunoregulation. Furthermore, the secretion of relevant immunoregulatory cytokines and growth factors including TGF-β, IL-6, IL-10, TNFα, IL-1β, VEGF, CXCL12, and CXCL10 remain comparable between non-irradiated and radiation-induced senescent CAFs. Importantly, radiation exposure modifies the cell surface expression of some key immunoregulatory receptors, including upregulation of CD73 and CD276.

Discussion

Our data suggest that CAFs do not participate in the release of danger signals or IFN-I secretion following radiotherapy. The immune phenotype of CAFs and radiation-induced senescent CAFs is similar, however, the observed elevation of some cell surface immunological receptors on irradiated CAFs could contribute to the establishment of an enhanced immunosuppressive TME after radiotherapy.

Radiation and Chemo-Sensitizing Effects of DNA-PK Inhibitors Are Proportional in Tumors and Normal Tissues

Inhibitors of DNA-dependent protein kinase (PRKDC; DNA-PK) sensitize cancers to radiotherapy and DNA-damaging chemotherapies, with candidates in clinical trials. However, the degree to which DNA-PK inhibitors also sensitize normal tissues remains poorly characterized. In this study, we compare tumor growth control and normal tissue sensitization following DNA-PK inhibitors in combination with radiation and etoposide. FaDu tumor xenografts implanted in mice were treated with 10 to 15 Gy irradiation ± 3 to 100 mg/kg AZD7648. A dose-dependent increase in time to tumor volume doubling following AZD7648 was proportional to an increase in toxicity scores of the overlying skin. Similar effects were seen in the intestinal jejunum, tongue, and FaDu tumor xenografts of mice assessed for proliferation rates at 3.5 days after treatment with etoposide or 5 Gy whole body irradiation ± DNA-PK inhibitors AZD7648 or peposertib (M3814). Additional organs were examined for sensitivity to DNA-PK inhibitor activity in ATM-deficient mice, where DNA-PK activity is indicated by surrogate marker γH2AX. Inhibition was observed in the heart, brain, pancreas, thymus, tongue, and salivary glands of ATM-deficient mice treated with the DNA-PK inhibitors relative to radiation alone. Similar reductions are also seen in ATM-deficient FaDu tumor xenografts where both pDNA-PK and γH2AX staining could be performed. DNA-PK inhibitor-mediated sensitization to radiation and DNA-damaging chemotherapy are not only limited to tumor tissues, but also extends to normal tissues sustaining DNA damage. These data are useful for interpretation of the sensitizing effects of DNA damage repair inhibitors, where a therapeutic index showing greater cell-killing effects on cancer cells is crucial for optimal clinical translation.

Modelling radiobiology

Radiotherapy has played an essential role in cancer treatment for over a century, and remains one of the best-studied methods of cancer treatment. Because of its close links with the physical sciences, it has been the subject of extensive quantitative mathematical modelling, but a complete understanding of the mechanisms of radiotherapy has remained elusive. In part this is because of the complexity and range of scales involved in radiotherapy-from physical radiation interactions occurring over nanometres to evolution of patient responses over months and years. This review presents the current status and ongoing research in modelling radiotherapy responses across these scales, including basic physical mechanisms of DNA damage, the immediate biological responses this triggers, and genetic- and patient-level determinants of response. Finally, some of the major challenges in this field and potential avenues for future improvements are also discussed.

Four Birds with One Stone: A Bandgap-Regulated Multifunctional Schottky Heterojunction for Robust Synergistic Antitumor Therapy upon Endo-/Exogenous Stimuli

Considering the profound impact of structure on heterojunction catalysts, the rational design of emerging catalysts with optimized energy band structures is required for antitumor efficiency. Herein, we select titanium nitride (TiN) and Pt to develop a multifunctional Schottky heterojunction named Pt/H-TiN&SRF (PHTS) nanoparticles (NPs) with a narrowed bandgap to accomplish "four birds with one stone" involving enzyo/sono/photo three modals and additional ferroptosis. The in situ-grown Pt NPs acted as electron traps that can cause the energy band to bend upward and form a Schottky barrier, thereby facilitating the separation of electron/hole pairs in exogenous stimulation catalytic therapy. In addition, endogenous catalytic reactions based on peroxidase (POD)- and catalase (CAT)-mimicking activities can also be amplified, triggering intense oxidative stress, in which CAT-like activity decomposes endogenous H2O2 into O2 alleviating hypoxia and provides reactants for sonodynamic therapy. Moreover, PHTS NPs can elicit mild photothermal therapy with boosted photothermal properties as well as ferroptosis with loaded ferroptosis inducer sorafenib for effective tumor ablation and apoptosis-ferroptosis synergistic tumor inhibitory effect. In summary, this paper proposes an attractive design for antitumor strategies and highlights findings for heterojunction catalytic therapy with potential in tumor theranostics.

Mechanoimmune-Driven Backpack Sustains Dendritic Cell Maturation for Synergistic Tumor Radiotherapy

Cell backpacks present significant potential in both therapeutic and diagnostic applications, making it essential to further explore their interactions with host cells. Current evidence indicates that backpacks can induce sustained immune responses. Our original objective was to incorporate a model antigen into the backpacks to promote dendritic cell maturation and facilitate antigen presentation, thereby inducing immune responses. However, we unexpectedly discovered that both antigen-loaded backpacks and empty backpacks demonstrated comparable abilities to induce dendritic cell maturation, resulting in nearly identical potency in T-cell proliferation. Our mechanistic studies suggest that the attachment of backpacks induces mechanical forces on dendritic cells via opening the PIEZO1 mechanical ion channel. This interaction leads to the remodeling of the intracellular cytoskeleton and facilitates the production of type I interferons by dendritic cells. Consequently, the mechano-immune-driven dendritic cell backpacks, when combined with radiotherapy, induce a robust antitumor effect. This research presents an avenue for leveraging mechanotransduction to enhance combination immunotherapeutic strategies, potentially leading to groundbreaking advancements in the field.

The use of master protocols for efficient trial design to evaluate radiotherapy interventions: a systematic review

The aim of this review was to highlight why the use of master protocols trial design is particularly useful for radiotherapy intervention trials where complex setup pathways (including quality assurance, user training, and integrating multiple modalities of treatment) may hinder clinical advances. We carried out a systematic review according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, reviewing the findings using a landscape analysis. Results were summarized descriptively, reporting on trial characteristics highlighting the benefits, limitations, and challenges of developing and implementing radiotherapy master protocols, with three case studies selected to explore these issues in more detail. Twelve studies were suitable for inclusion (4 platform trials, 3 umbrella trials, and 5 basket trials), evaluating a mix of solid tumor sites in both curative and palliative settings. The interventions were categorized into 1) novel agent and radiotherapy combinations; 2) radiotherapy dose personalization; and 3) device evaluation, with a case study provided for each intervention. Benefits of master protocol trials for radiotherapy intervention include protocol efficiency for implementation of novel radiotherapy techniques; accelerating the evaluation of novel agent drug and radiotherapy combinations; and more efficient translational research opportunities, leading to cost savings and research efficiency to improve patient outcomes. Master protocols offer an innovative platform under which multiple clinical questions can be addressed within a single trial. Due to the complexity of radiotherapy trial setup, cost and research efficiency savings may be more apparent than in systemic treatment trials. Use of this research approach may be the change needed to push forward oncological innovation within radiation oncology.

Identification of 6-Anilino Imidazo[4,5-c]pyridin-2-ones as Selective DNA-Dependent Protein Kinase Inhibitors and Their Application as Radiosensitizers

The dominant role of non-homologous end-joining in the repair of radiation-induced double-strand breaks identifies DNA-dependent protein kinase (DNA-PK) as an excellent target for the development of radiosensitizers. We report the discovery of a new class of imidazo[4,5-c]pyridine-2-one DNA-PK inhibitors. Structure-activity studies culminated in the identification of 78 as a nM DNA-PK inhibitor with excellent selectivity for DNA-PK compared to related phosphoinositide 3-kinase (PI3K) and PI3K-like kinase (PIKK) families and the broader kinome, and displayed DNA-PK-dependent radiosensitization of HAP1 cells. Compound 78 demonstrated robust radiosensitization of a broad range of cancer cells in vitro, displayed high oral bioavailability, and sensitized colorectal carcinoma (HCT116/54C) and head and neck squamous cell carcinoma (UT-SCC-74B) tumor xenografts to radiation. Compound 78 also provided substantial tumor growth inhibition of HCT116/54C tumor xenografts in combination with radiation. Compound 78 represents a new, potent, and selective class of DNA-PK inhibitors with significant potential as radiosensitizers for cancer treatment.

Components, Formulations, Deliveries, and Combinations of Tumor Vaccines

Tumor vaccines, an important part of immunotherapy, prevent cancer or kill existing tumor cells by activating or restoring the body's own immune system. Currently, various formulations of tumor vaccines have been developed, including cell vaccines, tumor cell membrane vaccines, tumor DNA vaccines, tumor mRNA vaccines, tumor polypeptide vaccines, virus-vectored tumor vaccines, and tumor-in-situ vaccines. There are also multiple delivery systems for tumor vaccines, such as liposomes, cell membrane vesicles, viruses, exosomes, and emulsions. In addition, to decrease the risk of tumor immune escape and immune tolerance that may exist with a single tumor vaccine, combination therapy of tumor vaccines with radiotherapy, chemotherapy, immune checkpoint inhibitors, cytokines, CAR-T therapy, or photoimmunotherapy is an effective strategy. Given the critical role of tumor vaccines in immunotherapy, here, we look back to the history of tumor vaccines, and we discuss the antigens, adjuvants, formulations, delivery systems, mechanisms, combination therapy, and future directions of tumor vaccines.

PTEN Depletion Increases Radiosensitivity in Response to Ataxia Telangiectasia-Related-3 (ATR) Inhibition in Non-Small Cell Lung Cancer (NSCLC)

Radiotherapy (RT) treatment is an important strategy for the management of non-small cell lung cancer (NSCLC). Local recurrence amongst patients with late-stage NSCLC remains a challenge. The loss of PTEN has been associated with radio-resistance. This study aimed to examine the efficacy of RT combined with ataxia telangiectasia-mutated Rad3-related (ATR) inhibition using Ceralasertib in phosphatase and tensin homolog (PTEN)-depleted NSCLC cells and to assess early inflammatory responses indicative of radiation pneumonitis (RP) after combined-modality treatment. Small hairpin RNA (shRNA) transfections were used to generate H460 and A549 PTEN-depleted models. Ceralasertib was evaluated as a single agent and in combination with RT in vitro and in vivo. Histological staining was used to assess immune cell infiltration in pneumonitis-prone C3H/NeJ mice. Here, we report that the inhibition of ATR in combination with RT caused a significant reduction in PTEN-depleted NSCLC cells, with delayed DNA repair and reduced cell viability, as shown by an increase in cells in Sub G1. Combination treatment in vivo significantly inhibited H460 PTEN-depleted tumour growth in comparison to H460 non-targeting PTEN-expressing (NT) cell-line-derived xenografts (CDXs). Additionally, there was no significant increase in infiltrating macrophages or neutrophils except at 4 weeks, whereby combination treatment significantly increased macrophage levels relative to RT alone. Overall, our study demonstrates that ceralasertib and RT combined preferentially sensitises PTEN-depleted NSCLC models in vitro and in vivo, with no impact on early inflammatory response indicative of RP. These findings provide a rationale for evaluating ATR inhibition in combination with RT in NSCLC patients with PTEN mutations.

Role of AURKB Inhibition in Reducing Proliferation and Enhancing Effects of Radiotherapy in Triple-Negative Breast Cancer

Breast cancer is a leading cause of cancer-related deaths in females. Triple-negative breast cancer (TNBC) subtype is the most aggressive form of breast cancer that lacks biomarkers and effective targeted therapies. Its high degree of heterogeneity as well as innate and acquired resistance to treatment creates further barriers in achieving positive clinical outcomes in TNBC. Thus, development of novel treatment approaches in TNBC is of high clinical significance. Multimodality approaches with targeted agents and radiotherapy (RT) are promising for increasing efficacy of treatment and circumventing resistance. Here we examined anticancer effects of the Aurora Kinase B (AURKB) inhibitor AZD1152 as a single agent and in combination with RT using various TNBC cell lines, MDA-MB-468, MDA-MB-231 and SUM-159. We observed that AZD1152 alone effectively inhibited colony formation in TNBC cell lines. The combination of AZD1152 at IC50 concentrations together with ionizing radiation further reduced colony formation as compared to the single agent treatment. Our data support the notion that inhibition of the AURKB pathway is a promising strategy for treatment and radiosensitization of TNBC and warrants further translational studies.

Engineering biomimetic nanosystem targeting multiple tumor radioresistance hallmarks for enhanced radiotherapy

Tumor cells establish a robust self-defense system characterized by hypoxia, antioxidant overexpression, DNA damage repair, and so forth to resist radiotherapy. Targeting one of these features is insufficient to overcome radioresistance due to the feedback mechanisms initiated by tumor cells under radiotherapy. Therefore, we herein developed an engineering biomimetic nanosystem (M@HHPt) masked with tumor cell membranes and loaded with a hybridized protein-based nanoparticle carrying oxygens (O2) and cisplatin prodrugs (Pt(IV)) to target multiple tumor radioresistance hallmarks for enhanced radiotherapy. After administration, M@HHPt actively targeted and smoothly accumulated in tumor cells by virtue of its innate homing abilities to realize efficient co-delivery of O2 and Pt(IV). O2 introduction induced hypoxia alleviation cooperated with Pt(IV) reduction caused glutathione consumption greatly amplified radiotherapy-ignited cellular oxidative stress. Moreover, the released cisplatin effectively hindered DNA damage repair by crosslinking with radiotherapy-produced DNA fragments. Consequently, M@HHPt-sensitized radiotherapy significantly suppressed the proliferation of lung cancer H1975 cells with an extremely high sensitizer enhancement ratio of 1.91 and the progression of H1975 tumor models with an excellent tumor inhibition rate of 94.7%. Overall, this work provided a feasible strategy for tumor radiosensitization by overcoming multiple radioresistance mechanisms.

Extracellular vesicles in anti-tumor drug resistance: Mechanisms and therapeutic prospects

Drug resistance presents a significant challenge to achieving positive clinical outcomes in anti-tumor therapy. Prior research has illuminated reasons behind drug resistance, including increased drug efflux, alterations in drug targets, and abnormal activation of oncogenic pathways. However, there's a need for deeper investigation into the impact of drug-resistant cells on parental tumor cells and intricate crosstalk between tumor cells and the malignant tumor microenvironment (TME). Recent studies on extracellular vesicles (EVs) have provided valuable insights. EVs are membrane-bound particles secreted by all cells, mediating cell-to-cell communication. They contain functional cargoes like DNA, RNA, lipids, proteins, and metabolites from mother cells, delivered to other cells. Notably, EVs are increasingly recognized as regulators in the resistance to anti-cancer drugs. This review aims to summarize the mechanisms of EV-mediated anti-tumor drug resistance, covering therapeutic approaches like chemotherapy, targeted therapy, immunotherapy and even radiotherapy. Detecting EV-based biomarkers to predict drug resistance assists in bypassing anti-tumor drug resistance. Additionally, targeted inhibition of EV biogenesis and secretion emerges as a promising approach to counter drug resistance. We highlight the importance of conducting in-depth mechanistic research on EVs, their cargoes, and functional approaches specifically focusing on EV subpopulations. These efforts will significantly advance the development of strategies to overcome drug resistance in anti-tumor therapy.

Mechanisms of traditional Chinese medicine overcoming of radiotherapy resistance in breast cancer

Breast cancer stands as the most prevalent malignancy among women, with radiotherapy serving as a primary treatment modality. Despite radiotherapy, a subset of breast cancer patients experiences local recurrence, attributed to the intrinsic resistance of tumors to radiation. Therefore, there is a compelling need to explore novel approaches that can enhance cytotoxic effects through alternative mechanisms. Traditional Chinese Medicine (TCM) and its active constituents exhibit diverse pharmacological actions, including anti-tumor effects, offering extensive possibilities to identify effective components capable of overcoming radiotherapy resistance. This review delineates the mechanisms underlying radiotherapy resistance in breast cancer, along with potential candidate Chinese herbal medicines that may sensitize breast cancer cells to radiotherapy. The exploration of such herbal interventions holds promise for improving therapeutic outcomes in the context of breast cancer radiotherapy resistance.

MOFs for next-generation cancer therapeutics through a biophysical approach-a review

Metal-organic frameworks (MOFs) have emerged as promising nanocarriers for cancer treatment due to their unique properties. Featuring high porosity, extensive surface area, chemical stability, and good biocompatibility, MOFs are ideal for efficient drug delivery, targeted therapy, and controlled release. They can be designed to target specific cellular organelles to disrupt metabolic processes in cancer cells. Additionally, functionalization with enzymes mimics their catalytic activity, enhancing photodynamic therapy and overcoming apoptosis resistance in cancer cells. The controllable and regular structure of MOFs, along with their tumor microenvironment responsiveness, make them promising nanocarriers for anticancer drugs. These carriers can effectively deliver a wide range of drugs with improved bioavailability, controlled release rate, and targeted delivery efficiency compared to alternatives. In this article, we review both experimental and computational studies focusing on the interaction between MOFs and drug, explicating the release mechanisms and stability in physiological conditions. Notably, we explore the relationship between MOF structure and its ability to damage cancer cells, elucidating why MOFs are excellent candidates for bio-applicability. By understanding the problem and exploring potential solutions, this review provides insights into the future directions for harnessing the full potential of MOFs, ultimately leading to improved therapeutic outcomes in cancer treatment.

Genetically programmable cell membrane-camouflaged nanoparticles for targeted combination therapy of colorectal cancer

Cell membrane-camouflaged nanoparticles possess inherent advantages derived from their membrane structure and surface antigens, including prolonged circulation in the bloodstream, specific cell recognition and targeting capabilities, and potential for immunotherapy. Herein, we introduce a cell membrane biomimetic nanodrug platform termed MPB-3BP@CM NPs. Comprising microporous Prussian blue nanoparticles (MPB NPs) serving as both a photothermal sensitizer and carrier for 3-bromopyruvate (3BP), these nanoparticles are cloaked in a genetically programmable cell membrane displaying variants of signal regulatory protein α (SIRPα) with enhanced affinity to CD47. As a result, MPB-3BP@CM NPs inherit the characteristics of the original cell membrane, exhibiting an extended circulation time in the bloodstream and effectively targeting CD47 on the cytomembrane of colorectal cancer (CRC) cells. Notably, blocking CD47 with MPB-3BP@CM NPs enhances the phagocytosis of CRC cells by macrophages. Additionally, 3BP, an inhibitor of hexokinase II (HK2), suppresses glycolysis, leading to a reduction in adenosine triphosphate (ATP) levels and lactate production. Besides, it promotes the polarization of tumor-associated macrophages (TAMs) towards an anti-tumor M1 phenotype. Furthermore, integration with MPB NPs-mediated photothermal therapy (PTT) enhances the therapeutic efficacy against tumors. These advantages make MPB-3BP@CM NPs an attractive platform for the future development of innovative therapeutic approaches for CRC. Concurrently, it introduces a universal approach for engineering disease-tailored cell membranes for tumor therapy.

Colorectal cancer-specific IFNβ delivery overcomes dysfunctional dsRNA-mediated type I interferon signaling to increase the abscopal effect of radiotherapy

BACKGROUND

Cancer-intrinsic type I interferon (IFN-I) production triggered by radiotherapy (RT) is mainly dependent on cytosolic double-stranded DNA (dsDNA)-mediated cGAS/STING signaling and increases cancer immunogenicity and enhances the antitumor immune response to increase therapeutic efficacy. However, cGAS/STING deficiency in colorectal cancer (CRC) may suppress the RT-induced antitumor immunity. Therefore, we aimed to evaluate the importance of the dsRNA-mediated antitumor immune response induced by RT in patients with CRC.

METHODS

Cytosolic dsRNA level and its sensors were evaluated via cell-based assays (co-culture assay, confocal microscopy, pharmacological inhibition and immunofluorescent staining) and in vivo experiments. Biopsies and surgical tissues from patients with CRC who received preoperative chemoradiotherapy (neoCRT) were collected for multiplex cytokine assays, immunohistochemical analysis and SNP genotyping. We also generated a cancer-specific adenovirus-associated virus (AAV)-IFNβ1 construct to evaluate its therapeutic efficacy in combination with RT, and the immune profiles were analyzed by flow cytometry and RNA-seq.

RESULTS

Our studies revealed that RT stimulates the autonomous release of dsRNA from cancer cells to activate TLR3-mediated IFN-I signatures to facilitate antitumor immune responses. Patients harboring a dysfunctional TLR3 variant had reduced serum levels of IFN-I-related cytokines and intratumoral CD8+ immune cells and shorter disease-free survival following neoCRT treatment. The engineered cancer-targeted construct AAV-IFNβ1 significantly improved the response to RT, leading to systematic eradication of distant tumors and prolonged survival in defective TLR3 preclinical models.

CONCLUSION

Our results support that increasing cancer-intrinsic IFNβ1 expression is an immunotherapeutic strategy that enhances the RT-induced antitumor immune response in locally patients with advanced CRC with dysfunctional TLR3.

Extracellular vesicles in cancer therapy: Roles, potential application, and challenges

Extracellular vesicles (EVs) have emerged as a novel cell-free strategy for the treatment of many diseases including cancer as they play important roles in cancer development and progression. Considering their natural capacity to facilitate cell-to-cell communication as well as their high physiochemical stability and biocompatibility, EVs serve as superior delivery systems for a wide range of therapeutic agents, including medicines, nanomaterials, nucleic acids, and proteins. Therefore, EVs-based cancer therapy is of greater interest to researchers. Mounting studies indicate that EVs can be improved in efficiency, specificity, and safety for cancer therapy. However, their heterogeneity of physicochemical properties and functions is not fully understood, hindering the achievement of bioactive EVs with high yield and purity. Herein, we paid more attention to the EVs applications and their significance in cancer therapy.

KDM3B Single-Nucleotide Polymorphisms Impact Radiation Therapy Toxicity Through Circular RNA-Mediated KDM3B Expression and Inflammatory Responses

PURPOSE

Genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) associated with radiation therapy (RT) toxicities in patients with prostate cancer. SNP rs17599026 in intron 21 of KDM3B is significantly associated with the development of late urinary toxicity, specifically in the increase in urinary frequency 2 years after RT compared with pretreatment conditions. The present study aimed to provide mechanistic insights for this association.

METHODS AND MATERIALS

Using human tissues and cell lines, we examined the protein expression of KDM3B and molecular mechanisms underlying the SNP modulation by variants of KDM3B SNP alleles. In animals with normal and heterozygous expressions of Kdm3b, we examined the relationship between Kdm3b expression and radiation toxicity.

RESULTS

KDM3B rs17599026 lies in a motif important for circular RNA expression that is responsible for sponging miRNAs to regulate KDM3B expression. Using a murine model with heterozygous deletion of the Kdm3b gene, we found that lower Kdm3b expression is associated with altered pattern of urination after bladder irradiation, which is related to differential degrees of tissue inflammation as measured by analyses of gene expression, lymphocyte infiltration, and noninvasive ultrasound imaging.

CONCLUSIONS

KDM3B SNPs can impact its expression through regulating noncoding RNA expression. Differential KDM3B expression underlies radiation toxicity through tissue inflammation at the molecular and physiological level. Our study outcome offers a foundation for mechanism-based mitigation for radiation toxicity for prostate cancer survivors.

Synergistic Effect of Ferroptosis-Inducing Nanoparticles and X-Ray Irradiation Combination Therapy

Ferroptosis, characterized by the induction of cell death via lipid peroxidation, has been actively studied over the last few years and has shown the potential to improve the efficacy of cancer nanomedicine in an iron-dependent manner. Radiation therapy, a common treatment method, has limitations as a stand-alone treatment due to radiation resistance and safety as it affects even normal tissues. Although ferroptosis-inducing drugs help alleviate radiation resistance, there are no safe ferroptosis-inducing drugs that can be considered for clinical application and are still in the research stage. Here, the effectiveness of combined treatment with radiotherapy with Fe and hyaluronic acid-based nanoparticles (FHA-NPs) to directly induce ferroptosis, considering the clinical applications is reported. Through the induction of ferroptosis by FHA-NPs and apoptosis by X-ray irradiation, the therapeutic efficiency of cancer is greatly improved both in vitro and in vivo. In addition, Monte Carlo simulations are performed to assess the physical interactions of the X-rays with the iron-oxide nanoparticle. The study provides a deeper understanding of the synergistic effect of ferroptosis and X-ray irradiation combination therapy. Furthermore, the study can serve as a valuable reference for elucidating the role and mechanisms of ferroptosis in radiation therapy.

The Safety and Efficacy of the Combination of Sacituzumab Govitecan and Palliative Radiotherapy-A Retrospective Multi-Center Cohort Study

Sacituzumab govitecan (SG) is a new treatment option for patients with metastatic triple-negative and hormone receptor-positive, HER2-negative breast cancer. This antibody-drug conjugate is currently approved as monotherapy. Palliative radiotherapy is frequently used to treat symptomatic metastases locally. Concurrent use of SG and irradiation was excluded in clinical trials of SG, and there are currently limited published data. We report here a systematic review, as well as a retrospective multi-center study of 17 patients with triple-negative breast cancer who received concurrent SG and radiotherapy. In these patients, concurrent use was found to be efficient, safe and well tolerated. There were no apparent differences in moderate or severe acute toxicity according to the timing of SG administration.

Integrated High-Throughput Screening and Large-Scale Isobolographic Analysis to Accelerate the Discovery of Radiosensitizers With Greater Selectivity for Cancer Cells

PURPOSE

High-throughput screening (HTS) platforms have been widely used to identify candidate anticancer drugs and drug-drug combinations; however, HTS-based identification of new drug-ionizing radiation (IR) combinations has rarely been reported. Herein, we developed an integrated approach including cell-based HTS and computational large-scale isobolographic analysis to accelerate the identification of radiosensitizing compounds acting strongly and more specifically on cancer cells.

METHODS AND MATERIALS

In a 384-well plate format, 160 compounds likely to interfere with the cell response to radiation were screened on human glioblastoma (U251-MG) and cervix carcinoma (ME-180) cell lines, as well as on normal fibroblasts (CCD-19Lu). After drug exposure, cells were irradiated or not and short-term cell survival was assessed by high-throughput cell microscopy. Computational large-scale dose-response and isobolographic approach were used to identify promising synergistic drugs radiosensitizing cancer cells rather than normal cells. Synergy of a promising compound was confirmed on ME-180 cells by an independent 96-well assay protocol, and finally, by the gold-standard colony forming assay.

RESULTS

We retained 4 compounds synergistic at 2 isoeffects in U251-MG and ME-180 cell lines and 11 compounds synergistically effective in only one cancer cell line. Among these 15 promising radiosensitizers, 5 compounds showed limited toxicity combined or not with IR on normal fibroblasts.

CONCLUSIONS

Overall, this study demonstrated that HTS chemoradiation screening together with large-scale computational analysis is an efficient tool to identify synergistic drug-IR combinations, with concomitant assessment of unwanted toxicity on normal fibroblasts. It sparks expectations to accelerate the discovery of highly desired agents improving the therapeutic index of radiation therapy.

Carbon-Iodine Polydiacetylene Nanofibers for Image-Guided Radiotherapy and Tumor-Microenvironment-Enhanced Radiosensitization

Radiotherapy is a mainstay treatment used in clinics for locoregional therapy, although it still represents a great challenge to improve the sensitivity and accuracy of radiotherapy for tumors. Here, we report the conjugated polymer, polydiiododiacetylene (PIDA), with an iodine content of 84 wt %, as a highly effective computed tomography (CT) contrast agent and tumor microenvironment-responsive radiosensitizer. PIDA exhibited several key properties that contribute to the improvement of precision radiotherapy. The integrated PIDA nanofibers confined within the tumor envelope demonstrated amplified CT intensity and prolonged retention, providing an accurate calculation of dose distribution and precise radiation delivery for CT image-guided radiotherapy. Therefore, our strategy pioneers PIDA nanofibers as a bridge to cleverly connect a fiducial marker to guide accurate radiotherapy and a radiosensitizer to improve tumor sensitivity, thereby minimizing potential damage to surrounding tissues and facilitating on-demand therapeutic intervention in tumors.

Nanomaterial-mediated modulation of the cGAS-STING signaling pathway for enhanced cancer immunotherapy

Despite the current promise of immunotherapy, many cancer patients still suffer from challenges such as poor immune response rates, resulting in unsatisfactory clinical efficacy of existing therapies. There is an urgent need to combine emerging biomedical discoveries and innovations in traditional therapies. Modulation of the cGAS-STING signalling pathway represents an important innate immunotherapy pathway that serves as a crucial DNA sensing mechanism in innate immunity and viral defense. It has attracted increasing attention as an emerging target for cancer therapy. The recent advancements in nanotechnology have led to the significant utilization of nanomaterials in cancer immunotherapy, owing to their exceptional physicochemical properties such as large specific surface area and efficient permeability. Given the rapid development of cancer immunotherapy driven by the cGAS-STING activation, this study reviews the latest research progress in employing nanomaterials to modulate this signaling pathway. Based on the introduction of the main activation mechanisms of cGAS-STING pathway, this review focuses on nanomaterials that mediate the agonists involved and effectively activate this signaling pathway. In addition, combination nanotherapeutics based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as other immunomodulation in tumor targeting therapy. STATEMENT OF SIGNIFICANCE: Given the rapid development of cancer immunotherapy driven by the cGAS / STING activation, this study reviews the latest research advances in the use of nanomaterials to modulate this signaling pathway. Based on the introduction of key cGAS-STING components and their activation mechanisms, this review focuses on nanomaterials that can mediate the corresponding agonists and effectively activate this signaling pathway. In addition, combination nanotherapies based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as immunomodulation in cancer therapy,.

CHARIOT: a phase I study of berzosertib with chemoradiotherapy in oesophageal and other solid cancers using time to event continual reassessment method

BACKGROUND

Berzosertib (M6620) is a highly potent (IC50  =  19 nM) and selective, first-in-class ataxia telangiectasia-mutated and Rad3-related protein kinase (ATR) inhibitor. This trial assessed the safety, preliminary efficacy, and tolerance of berzosertib in oesophageal cancer (A1 cohort) with RT and advanced solid tumours (A2 cohort) with cisplatin and capecitabine.

METHODS

Single-arm, open-label dose-escalation (Time-to-Event Continual Reassessment Method) trial with 16 patients in A1 and 18 in A2. A1 tested six dose levels of berzosertib with RT (35 Gy over 15 fractions in 3 weeks).

RESULTS

No dose-limiting toxicities (DLTs) in A1. Eight grade 3 treatment-related AEs occurred in five patients, with rash being the most common. The highest dose (240 mg/m2) was determined as the recommended phase II dose (RP2D) for A1. Seven DLTs in two patients in A2. The RP2D of berzosertib was 140 mg/m2 once weekly. The most common grade ≥3 treatment-related AEs were neutropenia and thrombocytopenia. No treatment-related deaths were reported.

CONCLUSIONS

Berzosertib combined with RT is feasible and well tolerated in oesophageal cancer patients at high palliative doses. Berzosertib with cisplatin and capecitabine was well tolerated in advanced cancer. Further investigation is warranted in a phase 2 setting.

CLINICAL TRIALS IDENTIFIER

EU Clinical Trials Register (EudraCT) - 2015-003965-27 ClinicalTrials.gov - NCT03641547.

International multidisciplinary consensus on the integration of radiotherapy with new systemic treatments for breast cancer: European Society for Radiotherapy and Oncology (ESTRO)-endorsed recommendations

Novel systemic therapies for breast cancer are being rapidly implemented into clinical practice. These drugs often have different mechanisms of action and side-effect profiles compared with traditional chemotherapy. Underpinning practice-changing clinical trials focused on the systemic therapies under investigation, thus there are sparse data available on radiotherapy. Integration of these new systemic therapies with radiotherapy is therefore challenging. Given this rapid, transformative change in breast cancer multimodal management, the multidisciplinary community must unite to ensure optimal, safe, and equitable treatment for all patients. The aim of this collaborative group of radiation, clinical, and medical oncologists, basic and translational scientists, and patient advocates was to: scope, synthesise, and summarise the literature on integrating novel drugs with radiotherapy for breast cancer; produce consensus statements on drug-radiotherapy integration, where specific evidence is lacking; and make best-practice recommendations for recording of radiotherapy data and quality assurance for subsequent studies testing novel drugs.

Results and lessons learnt from the WISTERIA phase I trial combining AZD1775 with cisplatin pre- or post-operatively in head and neck cancer

Background

Pre-clinical studies suggest AZD1775, a WEE1 kinase inhibitor, potentiates the activity of various chemotherapeutic agents.

Methods

WISTERIA was a prospective, parallel two-group, open-label, dose-finding, phase I clinical trial. Eligible patients had histologically confirmed oral, laryngeal, or hypopharyngeal squamous cell carcinoma, ECOG performance status 0/1, and aged ≥18-to-≤70 years. Primary outcomes were adverse events and defining recommended dose and schedule of AZD1775 in combination with cisplatin in pre-operative (Group A), or with cisplatin/radiotherapy in post-operative (Group B) patients. Dose determination was guided by a modified time-to-event continual reassessment method (mTITE-CRM).

Results

Between 30-Oct-2017 and 15-Jul-2019, nine patients were registered: Three into Group A and six into Group B. WISTERIA was closed early due to poor recruitment. Five dose-limiting toxicities (DLTs) were reported in four Group B patients. Seven serious adverse events were reported in four patients: One in Group A, and three in Group B. Three were related to treatment. No treatment-related deaths were reported.

Conclusions

WISTERIA did not complete its primary objectives due to poor recruitment and toxicities reported in Group B. However, use of the novel mTITE-CRM improved flexibility in reducing accrual suspension periods and should be considered for future trials in complex patient populations.

Clinical Trial Registration

ISRCTN76291951.

Hypoxia A Typical Target in Human Lung Cancer Therapy

Lung cancer (LC) is the leading cause of cancer-related death globally. Comprehensive knowledge of the cellular and molecular etiology of LC is perilous for the development of active treatment approaches. Hypoxia in cancer is linked with malignancy, and its phenotype is implicated in the hypoxic reaction, which is being studied as a prospective cancer treatment target. The hypervascularization of the tumor is the main feature of human LC, and hypoxia is a major stimulator of neo-angiogenesis. It was seen that low oxygen levels in human LC are a critical aspect of this lethal illness. However, as there is a considerable body of literature espousing the presumed functional relevance of hypoxia in LC, the direct measurement of oxygen concentration in Human LC is yet to be determined. This narrative review aims to show the importance and as a future target for novel research studies that can lead to the perception of LC therapy in hypoxic malignancies.

Mechanism of PARP inhibitor resistance and potential overcoming strategies

PARP inhibitors (PARPi) are a kind of cancer therapy that targets poly (ADP-ribose) polymerase. PARPi is the first clinically approved drug to exert synthetic lethality by obstructing the DNA single-strand break repair process. Despite the significant therapeutic effect in patients with homologous recombination (HR) repair deficiency, innate and acquired resistance to PARPi is a main challenge in the clinic. In this review, we mainly discussed the underlying mechanisms of PARPi resistance and summarized the promising solutions to overcome PARPi resistance, aiming at extending PARPi application and improving patient outcomes.

Deep Insight of Design, Mechanism, and Cancer Theranostic Strategy of Nanozymes

Since the discovery of enzyme-like activity of Fe3O4 nanoparticles in 2007, nanozymes are becoming the promising substitutes for natural enzymes due to their advantages of high catalytic activity, low cost, mild reaction conditions, good stability, and suitable for large-scale production. Recently, with the cross fusion of nanomedicine and nanocatalysis, nanozyme-based theranostic strategies attract great attention, since the enzymatic reactions can be triggered in the tumor microenvironment to achieve good curative effect with substrate specificity and low side effects. Thus, various nanozymes have been developed and used for tumor therapy. In this review, more than 270 research articles are discussed systematically to present progress in the past five years. First, the discovery and development of nanozymes are summarized. Second, classification and catalytic mechanism of nanozymes are discussed. Third, activity prediction and rational design of nanozymes are focused by highlighting the methods of density functional theory, machine learning, biomimetic and chemical design. Then, synergistic theranostic strategy of nanozymes are introduced. Finally, current challenges and future prospects of nanozymes used for tumor theranostic are outlined, including selectivity, biosafety, repeatability and stability, in-depth catalytic mechanism, predicting and evaluating activities.

Ultra-efficient radio-immunotherapy for reprogramming the hypoxic and immunosuppressive tumor microenvironment with durable innate immune memory

Radiosensitization efficacy of conventional tumor radiosensitizers has been frequently limited by insufficient competence for tumor microenvironment (TME) regulation and unfavorable cellular uptake at biological barriers. Here, we reported an ultra-efficient radiotherapy (RT) strategy by synthesizing an extracellular vesicles (EVs)-encapsulated hollow MnO2 to load metformin (Met@HMnER). It demonstrated significant RT enhancement by morphological control of catalyst and cellular respiratory depression against conventional solid MnO2. Furthermore, the target-modified EVs clothing retains outstanding metformin loading capacity while endowing enhanced biological barrier penetration. A noticeably durable innate immune activation of NK cells was triggered with this nanoplatform via the cGAS-STING pathway. The enhanced immunocompetence was verified on distal metastasis and in-situ recurrence model in vivo, This work paved a new path for synergistic and robust innate immunity in clinical cancer treatment.

Myoglobin-loaded gadolinium nanotexaphyrins for oxygen synergy and imaging-guided radiosensitization therapy

Gadolinium (Gd3+)-coordinated texaphyrin (Gd-Tex) is a promising radiosensitizer that entered clinical trials, but temporarily fails largely due to insufficient radiosensitization efficacy. Little attention has been given to using nanovesicles to improve its efficacy. Herein, Gd-Tex is transformed into building blocks "Gd-Tex-lipids" to self-assemble nanovesicles called Gd-nanotexaphyrins (Gd-NTs), realizing high density packing of Gd-Tex in a single nanovesicle and achieving high Gd-Tex accumulation in tumors. To elucidate the impact of O2 concentration on Gd-Tex radiosensitization, myoglobin (Mb) is loaded into Gd-NTs (Mb@Gd-NTs), resulting in efficient relief of tumor hypoxia and significant enhancement of Gd-Tex radiosensitization, eventually inducing the obvious long-term antitumor immune memory to inhibit tumor recurrence. In addition to Gd3+, the versatile Mb@Gd-NTs can also chelate 177Lu3+ (Mb@177Lu/Gd-NTs), enabling SPECT/MRI dual-modality imaging for accurately monitoring drug delivery in real-time. This "one-for-all" nanoplatform with the capability of chelating various trivalent metal ions exhibits broad clinical application prospects in imaging-guided radiosensitization therapy.

Radiosensitizing oxygenation changes in murine tumors treated with VEGF-ablation therapy are measurable using oxygen enhanced-MRI (OE-MRI)

PURPOSE

There is a significant need for a widely available, translatable, sensitive and non-invasive imaging biomarker for tumor hypoxia in radiation oncology. Treatment-induced changes in tumor tissue oxygenation can alter the sensitivity of cancer tissues to radiation, but the relative difficulty in monitoring the tumor microenvironment results in scarce clinical and research data. Oxygen-Enhanced MRI (OE-MRI) uses inhaled oxygen as a contrast agent to measure tissue oxygenation. Here we investigate the utility of dOE-MRI, a previously validated imaging approach employing a cycling gas challenge and independent component analysis (ICA), to detect VEGF-ablation treatment-induced changes in tumor oxygenation that result in radiosensitization.

METHODS

Murine squamous cell carcinoma (SCCVII) tumor-bearing mice were treated with 5 mg/kg anti-VEGF murine antibody B20 (B20-4.1.1, Genentech) 2-7 days prior to radiation treatment, tissue collection or MR imaging using a 7 T scanner. dOE-MRI scans were acquired for a total of three repeated cycles of air (2 min) and 100% oxygen (2 min) with responding voxels indicating tissue oxygenation. DCE-MRI scans were acquired using a high molecular weight (MW) contrast agent (Gd-DOTA based hyperbranched polygylcerol; HPG-GdF, 500 kDa) to obtain fractional plasma volume (fPV) and apparent permeability-surface area product (aPS) parameters derived from the MR concentration-time curves. Changes to the tumor microenvironment were evaluated histologically, with cryosections stained and imaged for hypoxia, DNA damage, vasculature and perfusion. Radiosensitizing effects of B20-mediated increases in oxygenation were evaluated by clonogenic survival assays and by staining for DNA damage marker γH2AX.

RESULTS

Tumors from mice treated with B20 exhibit changes to their vasculature that are consistent with a vascular normalization response, and result in a temporary period of reduced hypoxia. DCE-MRI using injectable contrast agent HPG-GDF measured decreased vessel permeability in treated tumors, while dOE-MRI using inhaled oxygen as a contrast agent showed greater tissue oxygenation. These treatment-induced changes to the tumor microenvironment result in significantly increased radiation sensitivity, illustrating the utility of dOE-MRI as a non-invasive biomarker of treatment response and tumor sensitivity during cancer interventions.

CONCLUSIONS

VEGF-ablation therapy-mediated changes to tumor vascular function measurable using DCE-MRI techniques may be monitored using the less invasive approach of dOE-MRI, an effective biomarker of tissue oxygenation that can monitor treatment response and predict radiation sensitivity.

Harnessing Hafnium-Based Nanomaterials for Cancer Diagnosis and Therapy

With the rapid development of nanotechnology and nanomedicine, there are great interests in employing nanomaterials to improve the efficiency of disease diagnosis and treatment. The clinical translation of hafnium oxide (HfO2 ), commercially namedas NBTXR3, as a new kind of nanoradiosensitizer for radiotherapy (RT) of cancers has aroused extensive interest in researches on Hf-based nanomaterials for biomedical application. In the past 20 years, Hf-based nanomaterials have emerged as potential and important nanomedicine for computed tomography (CT)-involved bioimaging and RT-associated cancer treatment due to their excellent electronic structures and intrinsic physiochemical properties. In this review, a bibliometric analysis method is employed to summarize the progress on the synthesis technology of various Hf-based nanomaterials, including HfO2 , HfO2 -based compounds, and Hf-organic ligand coordination hybrids, such as metal-organic frameworks or nanoscaled coordination polymers. Moreover, current states in the application of Hf-based CT-involved contrasts for tissue imaging or cancer diagnosis are reviewed in detail. Importantly, the recent advances in Hf-based nanomaterials-mediated radiosensitization and synergistic RT with other current mainstream treatments are also generalized. Finally, current challenges and future perspectives of Hf-based nanomaterials with a view to maximize their great potential in the research of translational medicine are also discussed.

Towards Data Driven RT Prescription: Integrating Genomics into RT Clinical Practice

The genomic era has significantly changed the practice of clinical oncology. The use of genomic-based molecular diagnostics including prognostic genomic signatures and new-generation sequencing has become routine for clinical decisions regarding cytotoxic chemotherapy, targeted agents and immunotherapy. In contrast, clinical decisions regarding radiation therapy (RT) remain uninformed about the genomic heterogeneity of tumors. In this review, we discuss the clinical opportunity to utilize genomics to optimize RT dose. Although from the technical perspective, RT has been moving towards a data-driven approach, RT prescription dose is still based on a one-size-fits all approach, with most RT dose based on cancer diagnosis and stage. This approach is in direct conflict with the realization that tumors are biologically heterogeneous, and that cancer is not a single disease. Here, we discuss how genomics can be integrated into RT prescription dose, the clinical potential for this approach and how genomic-optimization of RT dose could lead to new understanding of the clinical benefit of RT.

X-ray-responsive prodrugs and polymeric nanocarriers for multimodal cancer therapy

Radiotherapy as one of the most important cancer treatment modalities has been widely used in the therapy of various cancers. The clinically used radiation (e.g. X-ray) for radiotherapy has the advantages of precise spatiotemporal controllability and deep tissue penetration. However, traditional radiotherapy is frequently limited by the high side effects and tumor hypoxia. The combination of radiotherapy and other cancer treatment modalities may overcome the disadvantages of radiotherapy and improve the final therapeutic efficacy. In recent years, X-ray-activable prodrugs and polymeric nanocarriers have been extensively explored to introduce other treatment modalities in the precise position during radiotherapy, which can reduce the side toxicity of the drugs and improve the combination therapeutic efficacy. In this review, we focus on recent advances in X-ray-activable prodrugs and polymeric nanocarriers to boost X-ray-based multimodal synergistic therapy with reduced toxicity. The design strategies of prodrugs and polymeric nanocarriers are highlighted. Finally, challenges and outlooks of X-ray-activable prodrugs and polymeric nanocarriers are discussed.

Molecular mechanisms of tumor resistance to radiotherapy

BACKGROUND

Cancer is the most prevalent cause of death globally, and radiotherapy is considered the standard of care for most solid tumors, including lung, breast, esophageal, and colorectal cancers and glioblastoma. Resistance to radiation can lead to local treatment failure and even cancer recurrence.

MAIN BODY

In this review, we have extensively discussed several crucial aspects that cause resistance of cancer to radiation therapy, including radiation-induced DNA damage repair, cell cycle arrest, apoptosis escape, abundance of cancer stem cells, modification of cancer cells and their microenvironment, presence of exosomal and non-coding RNA, metabolic reprogramming, and ferroptosis. We aim to focus on the molecular mechanisms of cancer radiotherapy resistance in relation to these aspects and to discuss possible targets to improve treatment outcomes.

CONCLUSIONS

Studying the molecular mechanisms responsible for radiotherapy resistance and its interactions with the tumor environment will help improve cancer responses to radiotherapy. Our review provides a foundation to identify and overcome the obstacles to effective radiotherapy.

Design, Synthesis and Anticancer Evaluation of Nitroimidazole Radiosensitisers

The role of hypoxic tumour cells in resistance to radiotherapy, and in suppression of immune response, continues to endorse tumour hypoxia as a bona fide, yet largely untapped, drug target. Radiotherapy innovations such as stereotactic body radiotherapy herald new opportunities for classical oxygen-mimetic radiosensitisers. Only nimorazole is used clinically as a radiosensitiser, and there is a dearth of new radiosensitisers in development. In this report, we augment previous work to present new nitroimidazole alkylsulfonamides and we document their cytotoxicity and ability to radiosensitise anoxic tumour cells in vitro. We compare radiosensitisation with etanidazole and earlier nitroimidazole sulfonamide analogues and we identify 2-nitroimidazole and 5-nitroimidazole analogues with marked tumour radiosensitisation in ex vivo assays of surviving clonogens and with in vivo tumour growth inhibition.

Anti-Cancer and Radio-Sensitizing Properties of New Bimetallic (N-Heterocyclic Carbene)-Amine-Pt(II) Complexes

Bioactive NHC-transition metal complexes have shown promise as anti-cancer agents, but their potential use as radiosensitizers has been neglected so far. We disclose here a new series of bimetallic platinum(II) complexes displaying NHC-type bridging ligands, (bis-NHC)[trans-Pt(RNH₂)I₂]₂, that have been synthesized via a simple, two-step procedure. They display cytotoxicity in the micromolar range on cancerous cell lines, accumulate in cells, and bind to genomic DNA, by inducing DNA damages. Notably, these bimetallic complexes demonstrate significant radiosensitizing effects on both ovarian cells A2780 and nonsmall lung carcinoma cells H1299. Further investigations revealed that bimetallic species make irradiation-induced DNA damages more persistent by inhibiting repair mechanisms. Indeed, a higher and persistent accumulation of both γ-H2AX and 53BP1 foci post-irradiation was detected, in the presence of the NHC-Pt complexes. Overall, we provide the first in vitro evidence for the radiosensitizing properties of NHC-platinum complexes, which suggests their potential use in combined chemo-radio therapy protocols.

Cancer-associated fibroblasts in radiotherapy: Bystanders or protagonists?

BACKGROUND

The primary goal of radiotherapy (RT) is to induce cellular damage on malignant cells; however, it is becoming increasingly recognized the important role played by the tumor microenvironment (TME) in therapy outcomes. Therapeutic irradiation of tumor lesions provokes profound cellular and biological reconfigurations within the TME that ultimately may influence the fate of the therapy.

MAIN CONTENT

Cancer-associated fibroblasts (CAFs) are known to participate in all stages of cancer progression and are increasingly acknowledged to contribute to therapy resistance. Accumulated evidence suggests that, upon radiation, fibroblasts/CAFs avoid cell death but instead enter a permanent senescent state, which in turn may influence the behavior of tumor cells and other components of the TME. Despite the proposed participation of senescent fibroblasts on tumor radioprotection, it is still incompletely understood the impact that RT has on CAFs and the ultimate role that irradiated CAFs have on therapy outcomes. Some of the current controversies may emerge from generalizing observations obtained using normal fibroblasts and CAFs, which are different cell entities that may respond differently to radiation exposure.

CONCLUSION

In this review we present current knowledge on the field of CAFs role in radiotherapy; we discuss the potential tumorigenic functions of radiation-induced senescent fibroblasts and CAFs and we make an effort to integrate the knowledge emerging from preclinical experimentation with observations from the clinics. Video Abstract.

Mild photothermal/radiation therapy potentiates ferroptosis effect for ablation of breast cancer via MRI/PA imaging guided all-in-one strategy

BACKGROUND

Nanotheranostics advances anticancer management by providing therapeutic and diagnostic functions, that combine programmed cell death (PCD) initiation and imaging-guided treatment, thus increasing the efficacy of tumor ablation and efficiently fighting against cancer. However, mild photothermal/radiation therapy with imaging-guided precise mediating PCD in solid tumors, involving processes related to apoptosis and ferroptosis, enhanced the effect of breast cancer inhibition is not fully understood.

RESULTS

Herein, targeted peptide conjugated gold nano cages, iRGD-PEG/AuNCs@FePt NPs ternary metallic nanoparticles (Au@FePt NPs) were designed to achieve photoacoustic imaging (PAI)/Magnetic resonance imaging (MRI) guided synergistic therapy. Tumor-targeting Au@FePt forms reactive oxygen species (ROS), initiated by X-ray-induced dynamic therapy (XDT) in collaboration with photothermal therapy (PTT), inducing ferroptosis-augmented apoptosis to realize effective antitumor therapeutics. The relatively high photothermal conversion ability of Au@FePt increases the temperature in the tumor region and hastens Fenton-like processes to achieve enhanced synergistic therapy. Especially, RNA sequencing found Au@FePt inducting the apoptosis pathway in the transcriptome profile.

CONCLUSION

Au@FePt combined XDT/PTT therapy activate apoptosis and ferroptosis related proteins in tumors to achieve breast cancer ablation in vitro and in vivo. PAI/MRI images demonstrated Au@FePt has real-time guidance for monitoring synergistic anti-cancer therapy effect. Therefore, we have provided a multifunctional nanotheranostics modality for tumor inhibition and cancer management with high efficacy and limited side effects.