Cancer Radiosensitizers

Novel intravenous formulation for radiosensitization in osteosarcoma treatment

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and adolescents. While radiotherapy is an adjuvant treatment option for OS, particularly in cases of unresectable recurrent metastases, its efficacy remains limited. Enhancing radiosensitivity in OS cells is therefore crucial for improving treatment outcomes. Hafnium oxide, a known radiosensitizer, has demonstrated potential but its current formulation restricts its use to intratumoral administration, posing challenges for treating intraosseous tumors. The development of an intravenous formulation is thus highly desirable. Furthermore, radiotherapy resistance, driven by tumor hypoxia and an immunosuppressive microenvironment, further compromises its effectiveness. In this study, we synthesized hafnium-doped Prussian blue nanoparticles (HP) coated with a tannic acid-manganese metallophenol network (HPTM) to improve biocompatibility and enable intravenous administration. Following intravenous injection in a murine model of OS tibialis in situ tumors with lung metastases, HPTM effectively localized to the primary tumor. Within the acidic tumor microenvironment, manganese was released, activating the STING pathway and triggering anti-tumor immune responses. Moreover, near-infrared light irradiation of the Prussian blue component induced a photothermal effect, promoting apoptosis. Concurrently, under low-dose X-ray irradiation, HPTM augmented radiation energy deposition, generating reactive oxygen species and inducing DNA damage in tumor cells. This synergistic therapeutic approach significantly increased apoptosis in radiotherapy-resistant OS cells, reduced lung metastases, and suppressed primary tumor growth. These findings suggest a promising avenue for clinical translation, integrating radiosensitization, photothermal therapy, and STING pathway activation to overcome current limitations in OS radiotherapy.

Vacuum ultraviolet spectroscopy of pyrimidine derivatives: the effect of halogenation

As a prototypical molecule in the important class of halopyrimidines, 2-chloropyrimidine has been the subject of numerous spectroscopic studies. However, its absorption spectrum under vacuum ultraviolet (VUV) radiation has not yet been reported. Here, we close this gap by presenting high-resolution VUV photoabsorption cross-sections in the 3.7-10.8 eV range. Based on time-dependent density functional theory (TDDFT) calculations performed within the nuclear ensemble approach, we are able to characterize the main features of the measured spectrum. By comparing the present results for 2-chloropyrimidine with those of 2-bromopyrimidine and pyrimidine, we find that the effect of the halogen atom increases remarkably with the photon energy. The two lowest-lying absorption bands are overall similar for the three molecules, apart from some differences in the vibrational progressions in band I (3.7-4.6 eV) and minor energy shifts in band II (4.6-5.7 eV). Larger shifts appear in band III (5.7-6.7 eV), especially when comparing pyrimidine with the two halogenated species. The three molecules absorb more strongly in the region of band IV (6.7-8.2 eV), where the bands look qualitatively different because the mixing of excited configurations is strongly dependent on the species. At higher energies (8.2-10.8 eV) the three spectra no longer resemble each other. An important finding of this study is the very satisfactory comparison between experiment and theory, as the combination of TDDFT calculations with the nuclear ensemble approach yields cross-sections much closer to experiments than the simpler vertical approximation, in shape and magnitude, and across the whole spectral range surveyed here.

Guiqi Baizhu decoction enhances radiosensitivity in non-small cell lung cancer by inhibiting the HIF-1α/DNA-PKcs axis-mediated DNA repair

BACKGROUND

Radiotherapy is one of the main treatments for non-small cell lung cancer (NSCLC), and radiosensitivity is a determinant of its efficacy. Therefore, enhancing the radiosensitivity is of great significance to improve the clinical efficacy of non-small cell lung cancer (NSCLC).

PURPOSE

This study intended to investigate the radiosensitisation effect and mechanism of Guiqi Baizhu decoction (GQBZD) on non-small cell lung cancer (NSCLC) and the role of hypoxia-inducible factor-1 alpha (HIF-1α)/DNA-dependent protein kinase catalytic subunit (DNA-PKcs) axis-mediated DNA non-homologous end joining (NHEJ) repair in NSCLC radiotherapy.

STUDY DESIGN

In vivo experimental model was Lewis subcutaneous transplantation tumor model of in C57 black 6 (C57BL/6) mice, and in vitro experimental models were A549, H1299 and H460 cells.

METHODS

In vivo experimental model was Lewis subcutaneous transplantation tumor model of in C57 black 6 (C57BL/6) mice. After the model was successfully established, the tumor was irradiated locally with 4 Gy X-ray, and 10.465 g/kg Guiqi Baizhu Decoction (GQBZD) was administered by gavage on the second day after irradiation for a total of 10 days. The morphological changes in tumour tissues were observed by HE staining, Ki67 levels in tumour tissues were detected by immunohistochemistry, the apoptosis in tumour cells were detected by Tunel staining. In vitro experimental models were different NSCLC cells (A549, H1299 and H460), irradiated by 2 Gy X-rays and then intervened with 5%, 10% and 20% Guiqi Baizhu Decoction (GQBZD)-containing serum for 24 h. A549 stably-transformed cell lines knocking down and overexpressing HIF-1α were also constructed by lentiviral transfection. The cell proliferation was detected by CCK-8 and clone formation, the apoptosis and cell cycle was detected by flow cytometry. Network pharmacology and transcriptomics to investigate key targets and pathways of GQBZD effects on NSCLC irradiation, further validated by immunofluorescence and Western blot.

RESULTS

In vivo experiments confirmed that GQBZD combined with irradiation could inhibit the growth of Lewis subcutaneous transplantation tumor, reduce the expression of Ki67 and promote the apoptosis of tumour cells. In vitro experiments confirmed that GQBZD combined with irradiation inhibited the proliferation of different NSCLC cells, promoted NSCLC cell apoptosis and G2/M-phase arrest, and induced the expression of phosphorylated histone H2AX (γ-H2AX) in NSCLC cells, which showed a good radiosensitisation effect. Mechanistically, GQBZD exerts its radiosensitisation effect on NSCLC mainly through the HIF-1α signalling pathway. Meanwhile, under irradiation conditions, the expression of HIF-1α and DNA-PKcs were positively correlated, and HIF-1α had a regulatory effect on DNA-PKcs, promoting DNA-PKcs-dependent non-homologous end joining (NHEJ) repair. In addition, GQBZD combined irradiation down-regulated the expression of HIF-1α, DNA-PKcs, and NHEJ repair-related proteins in NSCLC cells, while reversing the expression of HIF-1α, DNA-PKcs, and NHEJ repair-related proteins in overexpressing HIF-1α A549 cell, thereby enhancing radiosensitivity in NSCLC.

CONCLUSION

This study provides an in-depth exploration of the radiosensitisation effect of GQBZD and provides an important experimental basis for the study of Chinese medicine in the field of cancer radiosensitisation, and further extends the extensibility of GQBZD on the basis of the previous study.

Replication stress response and radioresistance in lung cancer: Mechanistic insights and advanced therapeutic approaches

Lung cancer, the leading cause of cancer mortality globally, comprises mainly non-small cell lung cancer and small cell lung cancer. Its pathogenesis involves genetic mutations, environmental exposures, chronic inflammation, and tumor microenvironment interactions. Critical genes like TP53, RB1, KRAS, and EGFR often mutate, driving uncontrolled cell growth. Radiation therapy, a primary treatment, faces challenges with radioresistance due to DNA repair mechanisms and replication stress responses. Emerging therapeutic strategies target DNA repair pathways, cell cycle checkpoints, and immune responses to enhance radiosensitivity and counteract resistance. Promising approaches include PARP inhibitors, CDK inhibitors, EGFR blockers, and immunotherapies combined with radiation. Advances in understanding these mechanisms are crucial for developing targeted therapies to improve lung cancer patient outcomes. The present review focuses on elucidating the intricate mechanisms of lung cancer pathogenesis and radioresistance, while highlighting novel therapeutic strategies designed to overcome these challenges and improve treatment efficacy.

Antimicrobial applications of inorganic radiosensitizers and their potential in biofilm control

Biofilms are structured microbial communities embedded in a self-produced extracellular matrix. This lifestyle provides significant protection against environmental stressors such as desiccation, chemical treatments and even ionizing radiation. Radiation, while a well-established antibacterial strategy, can be less effective in biofilms. Biofilm superior resilience is due to several advantages such as the shielding provided by the matrix, the metabolic heterogeneity and adaptive stress responses of biofilm-associated cells. To address this challenge, researchers are increasingly employing combination strategies in antibiofilm treatment. Radiosensitizers, compounds originally developed to enhance the efficacy of radiation therapy in cancer treatment, have also garnered attention for their potential in antimicrobial applications. These compounds act by amplifying the effects of radiation, often through mechanisms such as increased oxidative stress or inhibition of DNA repair pathways. However, research on radiosensitizers in bacterial systems has focused on planktonic cultures, with limited studies exploring their effects on biofilms. Given the complexity and unique characteristics of biofilms, their response to radiosensitization remains poorly understood and requires further investigation. The use of radiosensitizers in conjunction with radiation presents a promising approach to overcome the inherent resilience of biofilms. By enhancing the susceptibility of biofilm-associated bacteria to radiation and simultaneously disrupting their protective structures, such approaches could lead to more effective and comprehensive solutions. Understanding the nuanced responses of biofilms to these combined treatments is essential for advancing both medical and environmental applications and addressing the challenge of biofilm persistence.

2-Nitroimidazole-Functionalized Superparamagnetic Iron Oxide Nanoparticles Detect Hypoxic Regions of Glioblastomas on MRI and Improve Radiotherapy Efficacy

The presence of hypoxic regions in tumors is associated with malignancy and is an important target for the high-precision diagnosis and treatment of tumors. Radioresistant hypoxic regions can be precisely identified and treated without the use of high doses of radiation if hypoxic region-specific contrast agents have a therapeutic effect. In this study, we synthesized a therapeutic-diagnostic complex agent (SPION-PG-NI) by combining polyglycerol-functionalized superparamagnetic iron oxide nanoparticles (SPION-PG, core diameter of 8.8 ± 1.9 nm) as an MRI contrast agent and 2-nitroimidazole (NI, a pimonidazole derivative) as a hypoxia-targeted ligand to visually evaluate hypoxic regions using MRI and improve radiotherapy efficacy at those sites. SPION-PG-NI showed a concentration-dependent contrast effect and had significantly higher accumulation in subcutaneous glioblastomas than the control agent, SPION-PG, 24 h after administration. Immunohistological evaluations showed that the SPION-PG-NI-accumulated regions corresponded well to hypoxic regions. SPION-PG-NI showed neither migration into the brain parenchyma nor neurotoxicity. Both SPION-PG and SPION-PG-NI decrease reactive oxygen species (ROS); however, they improve radiotherapy efficacy in hypoxic glioblastoma cells due to cytotoxicity. This effect of SPION-PG-NI was significantly higher than that of SPION-PG (p < 0.01). After 12 Gy irradiation, the mean normalized glioblastoma tumor volume on day 38 in the SPION-PG-NI group (288%) was significantly lower than that in the control group (882%) (p < 0.05). Collectively, these findings suggest the potential of SPION-PG-NI as a useful and safe tumor theranostic nanodevice for hypoxic imaging and improving radiotherapy efficacy.

Silver nanoparticles enhance neutron radiation sensitivity in cancer cells: An in vitro study

Growing interest in cancer radiotherapy has led to the application of nanoparticles as radiosensitizers. Here, we, for the first time, present the results of the radiosensitizing properties of silver nanoparticles (AgNPs) (possessing low toxicity towards human body) against cancer cells under neutron irradiation. Five standard cancer cultures (including glioblastoma, known for its resistance to conventional photon radiation) were used to evaluate the radiosensitizing properties of AgNPs suing MTT test, flow cytometry, and optical fluorescence microscopy. Neutron irradiation was applied in the absorbed dose of 0.5-1.5 Gy with an average neutron energy of 7.5 MeV. AgNPs increased the irradiation efficiency with the radiosensitivity enhancement ratios 1.02-2.32, for glioblastoma with ratios 1.22-1.47. It was revealed that at 1.5 Gy, AgNP-induced cytotoxicity made a significant contribution to the total observed radiosensitizer effect: on average, for five cell types, 29.8 and 96.2 % at the AgNP concentration of 0.2 and 1.6 μg/mL, respectively.

"Nanoparticle-based sensitizers in prostate cancer treatment: Enhancing radiotherapy efficacy through innovative nanotechnology: Narrative review"

For men with localized prostate cancer, radiotherapy (RT) remains a common therapeutic option. Although radiotherapy has had significant success, it remains an intractable issue in promoting radiation damage to tumor tissue while reducing adverse effects on healthy tissue. Chemicals or pharmacological substances known as radiosensitizers can increase the killing effect on tumor cells by accelerating DNA damage and indirectly producing free radicals. Of all the approaches to improving RT management outcomes, metal nanoparticle-enhanced radiation for prostate cancer patient therapy is a unique strategy that has sparked scientific attention in the past decade. Most current data is based on targeted RT with gold nanoparticles, among the most studied materials. Nevertheless, several novel materials have also been employed in preclinical settings. This study assesses existing dosimetric data on prostate cancer tissue as well as the likely future influence on treatment options and patient outcomes since further research in a clinical setting is necessary.

Nanoradiosentizers with X ray-actuatable supramolecular aptamer building units for programmable immunostimulatory T cell engagement

The insufficient activation and impaired effector functions of T cells in the immunosuppressive tumor microenvironment (TME) substantially reduces the immunostimulatory effects of radiotherapy. Herein, a multifunctional nanoradiosensitizer is established by integrating molecularly engineered aptamer precursors into cisplatin-loaded liposomes for enhancing radio-immunotherapy of solid tumors. Exposure to ionizing radiation (IR) following the nanoradiosensitizer treatment would induce pronounced immunogenic death (ICD) of tumor cells through cisplatin-mediated radiosensitization while also trigger the detachment of the aptamer precursors, which further self-assemble into PD-L1/PD-1-bispecific aptamer-based T cell engagers (CA) through the bridging effect of tumor-derived ATP to direct T cell binding onto tumor cells in the post-IR TME in a spatial-temporally programmable manner. The CA-mediated post-IR tumor-T cell engagement could override the immunosuppressive barriers in TME and enhance T cell-mediated recognition and elimination of tumor cells while minimizing systemic toxicities. Overall, this work offers an innovative approach to enhance the radio-immunotherapeutic efficacy in the clinics.

Dual-pathway tumor radiosensitization strategy based on engineered bacteria capable of targeted delivery of AuNPs and specific hypoxia alleviation

BACKGROUND

Radiotherapy efficacy remains constrained by two key challenges: dose-dependent toxicity to healthy tissues at high radiation doses and hypoxia-mediated tumor radioresistance. While radiosensitizers like gold nanoparticles can enhance tumor-specific radiation deposition, their targeted delivery to tumors presents a significant hurdle. Bacteria have emerged as promising bio-carriers that not only actively target tumors and penetrate complex microenvironments, but can also be genetically engineered as multifunctional platforms for radiosensitizer delivery and hypoxia alleviation.

RESULTS

An integrated nanosystem (PCM@AuNPs), composed of engineered bacteria (PCM) and gold nanoparticles (AuNPs), is used to increase the effectiveness of radiotherapy. PCM can target and colonize tumor sites more effectively, thus improving the delivery efficiency of radiosensitizers. Furthermore, PCM overexpresses catalase (CAT), which decomposes excess H2O2 into O2, helping to mitigate hypoxia in the TME. Under X-ray irradiation, PCM@AuNPs significantly enhance radiosensitization, leading to improved tumor growth inhibition while maintaining good biocompatibility.

CONCLUSIONS

An effective strategy based on an integrated nanosystem (PCM@AuNPs) for radiosensitization through multiple pathways is developed. This novel engineered bacterial strategy holds great promise for enhancing radiosensitization in cancer therapy.

Harnessing the power of traceable system C-GAP: homologous-targeting to fire up T-cell immune responses with low-dose irradiation

While radiotherapy-induced immunogenic cell death (ICD) holds potential for enhancing cancer immunotherapy, the conventional high-dose irradiation often leads to an immunosuppressive microenvironment and systemic toxicity. Therefore, a biomimetic nanoplatform cell membrane coated-nitrogen-doped graphene quantum dots combined with Au nanoparticles (C-GAP) was developed in this study. Firstly, homologous and traceable targeting features of C-GAP enables tumor-selective accumulation, providing reference for the selection of the timing of radiotherapy. Secondly, radiosensitization by C-GAP with Low-dose irradiation (LDI) amplifies reactive oxygen species (ROS) generation to trigger potent ICD. Thirdly, remarkable immune remodeling induced by C-GAP enhances CD8+ T cell infiltration and effector function. Single-cell RNA sequencing revealed that C-GAP-LDI combination upregulates TNF and CCL signaling pathway expression in tumor-infiltrating CD8+ T cells which potentiates tumor eradication. Our findings present a novel approach for safe and effective radioimmunotherapy, where C-GAP sensitized LDI achieves therapeutic enhancement through precise ICD induction and systemic immune activation.

Recent Progress in Radiosensitive Nanomaterials for Radiotherapy-Triggered Drug Release

Benefiting from the unique properties of ionizing radiation, such as high tissue penetration, spatiotemporal resolution, and clinical relevance compared with other external stimuli, radiotherapy-induced drug release strategies are showing great promise in developing effective and personalized cancer treatments. However, the requirement of high doses of X-ray irradiation to break chemical bonds for drug release limits the application of radiotherapy-induced prodrug activation in clinics. Recent advances in nanomaterials offer a promising approach for radiotherapy sensitization as well as integrating multiple modalities for improved therapy outcomes. In particular, the catalytic radiosensitization that utilizes electrons and energy generated by nanomaterials upon X-ray irradiation has demonstrated excellent potential for enhanced radiotherapy. In this Review, we summarize the design principles of X-ray-responsive chemical bonds for controlled drug release, strategies for catalytic radiosensitization, and recent progress of X-ray-responsive nanoradiosensitizers for enhanced radiotherapy by integration with chemotherapy, chemodynamic therapy, photodynamic therapy, photothermal therapy, gas therapy, and immunotherapy. Finally, we discuss the challenges of X-ray-responsive nanoradiosensitizers heading toward possible clinical translation. We expect that emerging strategies based on radiotherapy-triggered drug release will facilitate a frontier in accurate and effective cancer therapy in the near future.

Unravelling physical and radiobiological effects of proton boron fusion reaction with anionic metallacarboranes ([o-COSAN]-) in breast cancer cells

BACKGROUND

Protons, which are considered low-LET (Linear Energy Transfer) radiation, have an average RBE (relative biological effectiveness) of 1.1, with a range from 0.7 to 1.6. Thus, increasing biological effectiveness is of high interest in radiation oncology, and one way to enhance this is by using radiosensitizers. The present work investigates the effectiveness of the proton boron fusion reaction (PBFR) at the cellular level, using the sodium salt of metallacarborane [3,3'-Co(C2B9H11)2]- (Na[o-COSAN]) as the boron source, aiming to explore the potential of this type of boron clusters as a radiosensitizer for proton therapy. Therefore, the main goal was to test the hypothesis that loading the cells with boron will favour the PBFR at energies close to the Bragg peak. This would enhance the radiation-induced biological effects through the production of alpha-particles.

RESULTS

MDA-MB-231 breast cancer cells were used. Nuclear microscopy assessed [o-COSAN] uptake and distribution in single cells, while biodistribution was studied in tumor-bearing Balb/cSlc-nu/nu mice (MDA-MB-231 xenograft), with boron accumulation in target organs and tumor measured by ICP-OES. The cells were irradiated with a proton beam tuned to reach the PBFR resonance energy of 675 keV at the cell layer. DNA damage was assessed with the g-H2AX assay and cell survival with the clonogenic assay. Beam parameters and dose calibration curves using radiochromic films validated Monte Carlo dosimetry simulations. As expected, we observed higher biological damage in irradiated cells and the presence of [o-COSAN]- potentiated the damage. These results translate into a lower cellular viability, indicating that DNA damage imposed colonies smaller than their non-irradiated counterparts. This suggests that these damages either took longer time to be repaired or made the cells undergo less efficient survival mechanisms.

CONCLUSIONS

The radiosensitizing effect of [o-COSAN]- by strategic cellular 11B placement and proton irradiation intensifies the DNA damage, making the nucleus particularly susceptible and thus increasing the destructive capability of alpha-particles, generated in the nuclear fusion reaction, which may lead to increased cell mortality.

Comparison of biochemical changes induced in radioresistant prostate cancer cells by X-rays, radiosensitizing drugs, and a combined therapy using Raman microspectroscopy

Cancer radioresistance is a major problem in radiotherapy. Many strategies have been proposed to overcome this process including the use of radiosensitizing drugs such as C75 or silibinin. The overall result of all treatments (radiotherapy, chemotherapy, and combined treatment) is cancer cell death. On the other hand, each treatment affects cancer cells differently at the molecular level. However, little is known about biochemical changes induced in cancer cells by these treatments (especially in combined therapy) at the submicroscale. In this study, Raman microspectroscopy was applied to follow such changes induced in radioresistant prostate cancer cells by X-rays, radiosensitizing drugs (C75, silibinin), and a combined treatment. The analysis was supported by the Partial Least Squares Regression method to reveal spectral changes induced by an increasing dose of X-rays and concentrations of the drugs. The obtained regression coefficient (β) plots were compared to each other using a correlation coefficient (R). Our results show that PC-3 cells exhibit dose- and concentration-dependent responses to the treatment with different biochemical changes induced by X-rays in the presence of C75 and silibinin. Moreover, both drugs affect the cells differently at the submicroscale and independently from the X-ray's presence. Finally, C75 shows significant efficiency in the reduction of cell radioresistance.

Concurrent Amplification of Ferroptosis and Immune System Activation Via Nanomedicine-Mediated Radiosensitization for Triple-Negative Breast Cancer Therapy

Radiation therapy (RT) is one of the core therapies for current cancer management. However, the emergence of radioresistance has become a major cause of radiotherapy failure and disease progression. Therefore, overcoming radioresistance to achieve highly effective treatment for refractory tumors is significant yet challenging. Here, pH-responsive DSPE-PEoz modified hollow Bi2Se3-RSL3/diABZi (DP-HBN/RA) nanomedicine is designed as a radiation sensitizer for efficient treatment of triple-negative breast cancer by simultaneously amplifying ferroptosis and immune system activation. DP-HBN/RA can efficiently concentrate X-ray radiation energy inside the tumor, thereby promoting precise ionizing radiation exposure in tumor cells to produce large amounts of reactive oxygen species (ROS), leading to lipid peroxidation-induced ferroptosis. Meanwhile, ferroptotic cell death is intensified through the inactivation of GPX4 by RSL3 released from DP-HBN/RA to acidic conditions in the tumor microenvironment. Additionally, DP-HBN/RA enhances RT efficacy to exacerbate unrepairable DNA damage and release DNA fragments that activate the cGAS-STING signal pathway, evoking a systematic immune response. Ingeniously, the released diABZi reinforces cGAS-STING activation to boost the immunology antitumor effect. This work links the induction of ferroptosis and the initiation of systematic immune response to achieve highly effective tumor suppression, which opens up new avenues for future treatments of refractory tumors.

Advances in nanoparticle-based radiotherapy for cancer treatment

Radiotherapy has long been recognized as an effective conventional approach in both clinical and scientific research, primarily through mechanisms involving DNA destruction or the generation of reactive oxygen species to target tumors. However, significant challenges persist, including the unavoidable damage to normal tissues and the development of radiation resistance. As a result, nanotechnology-based radiotherapy has garnered considerable attention for its potential to enhance precision in irradiation, improve radiosensitization, and achieve therapeutic advancements. Importantly, radiotherapy alone frequently falls short of fully eradicating tumors. Consequently, to augment the efficacy of radiotherapy, it is often integrated with other therapeutic strategies. This review elucidates the mechanisms of radiotherapy sensitization based on diverse nanoparticles. Typically, radiotherapy is sensitized through augmenting reactive oxygen species production, targeted radiotherapy, hypoxia relief, enhancement of antitumor immune microenvironment, and G2/M cell cycle arrest. Moreover, the incorporation of nanoparticle-based anti-tumor strategies with radiotherapy markedly enhances the current state of radiotherapy. Additionally, a compilation of clinical trials utilizing nano-radioenhancers is presented. Finally, future prospects for clinical translation in this field are thoroughly examined.

Enhancing Chordoma Radiotherapy: Ta@PVP Nanoparticles as Potent Radiosensitizers

Surgical resection and high-dose radiotherapy constitute the standard therapeutic approaches for chordoma. However, the efficacy of radiotherapy is often compromised by the tumor microenvironment's hypoxic conditions, which confer radiation resistance, and by the potential damage to adjacent spinal cord and neural structures from elevated radiation doses. To address these challenges, we employed high biocompatible poly(vinylpyrrolidone)-modified tantalum nanoparticles (Ta@PVP NPs) as a potent radiosensitizer to augment the radiotherapy sensitivity of chordoma. Upon exposure to X-ray irradiation, Ta@PVP NPs demonstrated the capability to efficiently deposit X-ray radiation energy within the tumor microenvironment, subsequently generating reactive oxygen species (ROS) that induce oxidative stress in the tumor. Both in vitro and in vivo experiments revealed that Ta@PVP NPs significantly enhanced the cytotoxic effects of X-ray, thereby markedly inhibiting the proliferation of chordoma cells and impeding tumor growth. This study explored the radiosensitization potential of Ta@PVP NPs in the context of chordoma, highlighting the application of radiosensitizers as a promising strategy to augment the efficacy of chordoma radiotherapy.

Vitamin D sensitizes cervical cancer to radiation-induced apoptosis by inhibiting autophagy through degradation of Ambra1

Cervical cancer (CC) is becoming a major health issue globally, and radiotherapy plays a crucial role in its treatment. However, the prognosis of some patients remains poor due to tumor resistance to the therapy. This study aimed to explore whether vitamin D could confer a more radiosensitive phenotype in CC based on our previous findings and detection using the database. We found that vitamin D sensitized vitamin D receptor (VDR)-positive CC cells (Siha and Caski) to the cytotoxic effects of radiation in vivo and in vitro. We examined conventional radiation-induced cell death, such as DNA damage and cell cycle arrest, in vitamin D-treated cells to detect the underlying mechanism, but no association was observed between them. Subsequently, our proteome analysis exhibited that autophagy was reduced in irradiated CCs treated with vitamin D, and apoptosis displayed the opposite effect. Moreover, we confirmed that vitamin D-pretreated irradiated cells displayed reduced autophagy activity mediated by the Ambra1 downregulation, and the elevation of apoptosis was attributed to the activation of caspase 8. Importantly, the pharmacological inhibition of caspases or the Ambra1 overexpression could restore tumor proliferation under the vitamin D and radiation combination treatment. Hence, the aforementioned findings revealed the essential impact of vitamin D in terms of enhancing radiosensitivity in CC meditated by inhibiting autophagy and proposed the addition of vitamin D as a viable strategy to improve the therapeutic efficacy of VDR-positive CC.

METTL3 methylated KIF15 promotes nasopharyngeal carcinoma progression and radiation resistance by blocking ATG7-mediated autophagy through the activation of STAT3 pathway

BACKGROUND

Resistance to radiotherapy is a major component in the failure of nasopharyngeal carcinoma (NPC) treatment. Enhancing autophagy in nasopharyngeal carcinoma may increase its radiation sensitivity, making it critical to find autophagy-modulating targets.

METHODS

The level of KIF15 was determined in NPC patients. Then, radiation-resistant NPC cells were produced to explore the mechanism in NPC. KIF15 was suppressed, and cell function and autophagy-related variables were examined in radiation-resistant NPC cells. Then the autophagy pathway was blocked, and the link between KIF15 and autophagy was confirmed. Finally, an NPC murine model was established, with tumors implanted in aberrant sites, and the relationship discovered at the cell level was confirmed in vivo. All statistical significance was determined using the student's t-test and one-way ANOVA.

RESULTS

Elevated amounts of KIF15 were discovered to be significantly expressed in NPC tissues and played a role in the radioresistance of NPC, a phenomenon attributed to METTL3-mediated m6A methylation. Blocking KIF15 resulted in decreased cell proliferation, increased cell death, and the activation of autophagy, ultimately making NPC more sensitive to radiation. This also resulted in decreased tumor development and increased levels of autophagy and apoptosis in vivo KIF15 interacted with STAT3, retaining it in the cytoplasm. Overexpression of STAT3 reversed the inhibitory effects of KIF15 knockdown on NPC and also reversed the influence of sh-KIF15 on autophagy activation. Inhibition of KIF15 decreased the inhibitory effect of STAT3 on ATG7, thereby upregulating autophagy activation in radio-resistant NPC cells.

CONCLUSION

The increased expression of KIF15 was found to be associated with the progression of NPC and play a role in the development of radioresistance in NPC. Inhibiting KIF15 was shown to impede tumor growth and improve the sensitivity of NPC to radiotherapy by triggering autophagy via the STAT3/ATG7 pathway.

How the Versatile Self-Assembly in Drug Delivery System to Afford Multimodal Cancer Therapy?

The rapid development of self-assembly technology during the past few decades has effectively addressed plenty of the issues associated with carrier-based drug delivery systems, such as low loading efficiency, complex fabrication processes, and inherent toxicity of carriers. The integration of nanoscale delivery systems with self-assembly techniques has enabled efficient and targeted self-administration of drugs, enhanced bioavailability, prolonged circulation time, and controllable drug release. Concurrently, the limitations of single-mode cancer treatment, including low bioavailability, poor therapeutic outcomes, and significant side effects, have highlighted the urgent need for multimodal combined antitumor therapies. Set against the backdrop of multimodal cancer therapy, this review summarizes the research progress and applications of a large number of self-assembled drug delivery platforms, including natural small molecule self-assembled, carrier-free self-assembled, amphiphilic polymer-based self-assembled, peptide-based self-assembled, and metal-based self-assembled nano drug delivery systems. This review particularly analyzes the latest advances in the application of self-assembled nano drug delivery platforms in combined antitumor therapies mediated by chemotherapy, phototherapy, radiotherapy, sonodynamic therapy, and immunotherapy, providing innovative research insights for further optimization and expansion of self-assembled nano drug delivery systems in the clinical translation and development of antitumor combined therapy.

Reactive oxygen species: Janus-faced molecules in the era of modern cancer therapy

Oxidative stress, that is, an unbalanced increase in reactive oxygen species (ROS), contributes to tumor-induced immune suppression and limits the efficacy of immunotherapy. Cancer cells have inherently increased ROS production, intracellularly through metabolic perturbations and extracellularly through activation of NADPH oxidases, which promotes cancer progression. Further increased ROS production or impaired antioxidant systems, induced, for example, by chemotherapy or radiotherapy, can preferentially kill cancer cells over healthy cells. Inflammatory cell-derived ROS mediate immunosuppressive effects of myeloid-derived suppressor cells and activated granulocytes, hampering antitumor effector cells such as T cells and natural killer (NK) cells. Cancer therapies modulating ROS levels in tumors may thus have entirely different consequences when targeting cancer cells versus immune cells. Here we discuss the possibility of developing more efficient cancer therapies based on reduction-oxidation modulation, as either monotherapies or in combination with immunotherapy. Short-term, systemic administration of antioxidants or drugs blocking ROS production can boost the immune system and act in synergy with immunotherapy. However, prolonged use of antioxidants can instead enhance tumor progression. Alternatives to systemic antioxidant administration are under development where gene-modified or activated T cells and NK cells are shielded ex vivo against the harmful effects of ROS before the infusion to patients with cancer.

Golden era of radiosensitizers

The past 30 years have brought undeniable progress in medicine, biology, physics, and research. Knowledge of the nature of the human body, diseases, and disorders has been constantly improving, and the same is true regarding their treatment and diagnosis. One of the greatest advances in recent years has been the introduction of nanoparticles (NPs) into medicine. NPs refer to a material at a nanometer scale (0.1-100 nm) with features (specific physical, chemical, and biological properties) that are broadly and increasingly used in the medical field. Their applications in cancer treatment and radiotherapy seem particularly attractive. In this field, inorganic/metal NPs with high atomic number Z have been employed mainly due to their ability to enhance ionizing radiation's photoelectric and Compton effects and thereby increase conventional radiation therapy's efficacy. The improvement NPs enable relates to their enhanced permeation ability and longer retention effect in tumor cells, capacity to reduce toxicity of commercially available cancer drugs through advanced NPs drug delivery systems, radiation sensitizers of tumors, or enhancers of radiation doses to tumors. Advanced options according to size, core, and surface modification allow even such multimodal approaches in therapy as nanotheranostics or combined treatments. The current state of knowledge emphasizes the role of gold nanoparticles (AuNPs) in sensitizing tumors to radiation. We have reviewed AuNPs and their radiosensitizing power during radiation treatment. Our results are divided into groups based on AuNPs' surface modification and/or core structure design. This study provides a complete summary of the in vivo sensitizing effect of AuNPs, surface-modified AuNPs, and AuNPs combined with different elements, providing evidence for further successful veterinarian and clinical implementation.

Loss of MACROD2 drives radioresistance but not cisplatin resistance in HPV-positive head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer type worldwide. In recent years, there has been an increase in the rate of HNSCC cases attributed to the infection of the oropharynx by the human papillomavirus (HPV). Given the significant treatment-related toxicities of the current standard of care for HPV-positive HNSCC, there is an urgent need for the development of precision patient stratification and treatment strategies to improve patients' quality of life while maintaining excellent survival rates. We have previously carried out whole genome sequencing of HPV+ HNSCC tumors that failed concurrent cisplatin and radiation treatment and discovered that MACROD2 deletion is enriched among these tumors. In the current study, we sought to investigate the mechanistic role of MACROD2 in HPV+ HNSCC treatment resistance. Our results indicate that MACROD2 depletion in HNSCC cell lines leads to increased cell viability and colony formation capacity. Interestingly, MACROD2 depletion did not alter cisplatin sensitivity but led to an increase in radiation resistance of HPV+ HNSCC cell lines. RNA sequencing and immunofluorescence microscopy demonstrated that MACROD2-depleted HPV+ HNSCC cells displayed elevated levels of hypoxia and an altered DNA damage response. Taken together, this study establishes and characterizes the role of MACROD2 in HPV+ HNSCC radioresistance. Further work is needed to validate MACROD2 as a biomarker of treatment failure and to understand how to overcome the identified molecular mechanisms of resistance.

Barriers to Radiotherapy Access in Sub-Saharan Africa for Patients with Cancer: A Systematic Review

BACKGROUND

Access to radiotherapy services is critical for effective cancer treatment, yet patients in sub-Saharan Africa face numerous barriers to accessing these services. The region is experiencing a significant increase in cancer cases, with a more than 85% increase in cancer cases reported in the past decade, highlighting the critical role of radiotherapy in enhancing patient prognosis. This systematic review aims to explore the barriers to radiotherapy access in sub-Saharan Africa. The barriers explored will be used to inform the development of the framework to improve access to radiotherapy in the Gauteng provinces, South Africa.

METHODS

A systematic search of electronic databases was conducted to identify relevant studies published between January 2013 and December 2023. Studies reporting on barriers to radiotherapy access in SSA were included and put into four categories of barriers: health system factors, patient sociodemographic factors, patient factors, and provider factors. Data were synthesised using thematic analysis.

RESULTS

This review identifies geographical, financial, cultural, logistical, and systemic barriers to radiotherapy access in sub-Saharan Africa, including limited infrastructure, long travel distances, and inequitable distribution of services. Systemic barriers, including policy gaps and governance issues, also contribute to the inequitable distribution of radiotherapy services in the region.

CONCLUSIONS

This systematic review highlights the diverse array of barriers to radiotherapy access in sub-Saharan Africa and emphasises the urgent need for targeted interventions to address these challenges.

Revolutionizing head and neck squamous cell carcinoma treatment with nanomedicine in the era of immunotherapy

Head and neck squamous cell carcinoma (HNSCC) is a prevalent malignant tumor globally. Despite advancements in treatment methods, the overall survival rate remains low due to limitations such as poor targeting and low bioavailability, which result in the limited efficacy of traditional drug therapies. Nanomedicine is considered to be a promising strategy in tumor therapy, offering the potential for maximal anti-tumor effects. Nanocarriers can overcome biological barriers, enhance drug delivery efficiency to targeted sites, and minimize damage to normal tissues. Currently, various nano-carriers for drug delivery have been developed to construct new nanomedicine. This review aims to provide an overview of the current status of HNSCC treatment and the necessity of nanomedicine in improving treatment outcomes. Moreover, it delves into the research progress of nanomedicine in HNSCC treatment, with a focus on enhancing radiation sensitivity, improving the efficacy of tumor immunotherapy, effectively delivering chemotherapy drugs, and utilizing small molecule inhibitors. Finally, this article discussed the challenges and prospects of applying nanomedicine in cancer treatment.

ML385 promotes ferroptosis and radiotherapy sensitivity by inhibiting the NRF2-SLC7A11 pathway in esophageal squamous cell carcinoma

Radiotherapy is important in treating esophageal squamous cell carcinoma (ESCC) comprehensively. Resistance to radiotherapy is a prominent factor contributing to treatment failure in patients with ESCC. The objective of this study was to investigate the impact of ML385, an inhibitor of nuclear factor erythroid 2-related factor 2 (NRF2), on the radiosensitivity of ESCC and elucidate its underlying mechanism. We treated KYSE150 and KYSE510 cells with ML385 and ionising radiation separately or simultaneously, and observed the proliferation, apoptosis, cell cycle and ferroptosis of different conditions by colony formation assay and flow cytometry. Our findings reveal that NRF2 was activated by radiation and translocated from the cytoplasm to the nucleus after radiation. However, ML385 inhibited the expression and cytoplasm-to-nucleus translocation of NRF2. Compared with radiation, ML385 combined with radiation exhibited a significant inhibition on the clone formation ability of ESCC cells, induced apoptosis and promoted G2/M phase arrest. The treatment of ML385 combined with radiation markedly increased ROS and lipid peroxidation levels and decreased glutathione levels compared with the control, thus promoting the occurrence of ferroptosis. In addition, the expression trend of NRF2 was the same as that of proteins related ferroptosis, such as SLC7A11 and GPX4. After overexpression of SLC7A11, we found that significantly restored glutathione levels and alleviated ML385 combined with radiation-induced lipid peroxidation, indicating that ML385 plays a key role in radiotherapy sensitization by inhibiting the NRF2-SLC7A11 pathway. In vivo, ML385 also promoted the killing effect of radiation on xenografted tumours in nude mice. This study identifies NRF2 inhibitor ML385 as a radiosensitizer of ESCC, which highlights the therapeutic potential of the NRF2-SLC7A11 pathway and provides a deeper understanding of the mechanism of ferroptosis in esophageal squamous cell carcinoma.

Dual-targeted TfRA4-DNA1-Ag@AuNPs: An innovative radiosensitizer for enhancing radiotherapy in glioblastoma multiforme

Radiation therapy (RT) is one of the most effective and widely used treatment methods for glioblastoma multiforme (GBM). However, its efficacy is often compromised by the inherent radioresistance of tumor cells, while the restrictive nature of the blood-brain barrier (BBB) specifically impedes the delivery of radiosensitizer. Thus, we constructed and characterized polyethylene glycol (PEG)-functionalized silver-gold core-shell nanoparticles (PSGNPs) targeting both BBB (TfRA4) and GBM (DNA1) (TDSGNPs). Afterwards, studies conducted both in vitro and in vivo were employed to assess the BBB penetration capabilities, abilities of GBM targeting and radiosensitization effect. Transmission electron microscope images of PSGNPs showed a core-shell structure, and the results of ultraviolet-visible absorption spectroscopy and dynamic light scattering displayed that TDSGNPs were successfully constructed with excellent dispersion properties. TDSGNPs could be specifically taken up by U87MG cells and the uptake peaked at 24 h. TDSGNPs combined with RT obviously increased the apoptosis proportion of the cells. It was shown by the in vitro and in vivo investigations that TDSGNPs could target U87MG cells after crossing the BBB, and further study revealed that TDSGNPs showed an uptake peak in the tumor sites after 3 h intravenous injection. The radiosensitization of TDSGNPs was better than that of the nanoparticles modified with single aptamers and the median survival of tumor-bearing mice was greatly extended. This study demonstrated that TDSGNPs could penetrate BBB to target GBM, functioning as a promising radiosensitizer for the targeted therapy of GBM.

Nanocarrier-Based Drug Delivery Systems Targeting Kidney Diseases

BACKGROUND

The potential applications of nanotechnology in the medical field have become increasingly recognized in recent years. Nanocarriers have emerged as a versatile tool, offering a wide range of applications due to their unique properties. In addition to the targeted drugs delivery, nanocarriers have also proven to be extremely effective in imaging and diagnostics. Continuous advances in nanotechnology have paved the way for innovative solutions to complex challenges in human health, shaping the future of nanotechnology and its applications.

SUMMARY

By exploring different types of nanoparticles, this review delves into the different characteristics that can be tailored to enhance their kidney access. Although the structural complexity of the kidney may prevent nanocarriers passage, optimization of nanocarrier characteristics such as shape, size, charge, and surface modifications may overcome these barriers, allowing for targeted delivery. By harnessing the potential of nanoparticles, researchers aim to develop targeted and efficient therapies that can address various kidney-related disorders.

KEY MESSAGES

This review highlights the promising advancements in nanotechnology and their potential impact on improving the therapeutic outcomes for several kidney diseases.

Blocking ACSL6 Compromises Autophagy via FLI1-Mediated Downregulation of COLs to Radiosensitize Lung Cancer

Lung cancer (LC) is the leading cause of cancer-related mortality worldwide. Radiotherapy is the main component of LC treatment; however, its efficacy is often limited by radioresistance development, resulting in unsatisfactory clinical outcomes. Here, we found that LC radiosensitivity is up-regulated by decreased expression of long-chain acyl-CoA synthase 6 (ACSL6) after irradiation. Deletion of ACSL6 results in significant elevation of Friend leukemia integration 1 transcription factor (FLI1) and a marked decline of collagens (COLs). Blocking of ACSL6 impairs the tumor growth and upregulates FLI1, which reduces the levels of COLs and compromises irradiation-induced autophagy, leading to considerable therapeutic benefits during radiotherapy. Moreover, the direct interaction between ACSL6 and FLI1 and engagement between FLI1 and COLs indicates the involvement of the ACSL6-FLI1-COL axis. Finally, the potently adjusted autophagy flux reduces its otherwise contributive capability in surviving irradiation stress and leads to satisfactory radiosensitization for LC radiotherapy. These results demonstrate that enhanced ACSL6 expression promotes the aggressive performance of irradiated LC through increased FLI1-COL-mediated autophagy flux. Thus, the ACSL6-FLI1-Col-autophagy axis may be targeted to enhance the radiosensitivity of LC and improve the management of LC in radiotherapy.

Atomic-scale strain engineering of atomically resolved Pt clusters transcending natural enzymes

Strain engineering plays an important role in tuning electronic structure and improving catalytic capability of biocatalyst, but it is still challenging to modify the atomic-scale strain for specific enzyme-like reactions. Here, we systematically design Pt single atom (Pt1), several Pt atoms (Ptn) and atomically-resolved Pt clusters (Ptc) on PdAu biocatalysts to investigate the correlation between atomic strain and enzyme-like catalytic activity by experimental technology and in-depth Density Functional Theory calculations. It is found that Ptc on PdAu (Ptc-PA) with reasonable atomic strain upshifts the d-band center and exposes high potential surface, indicating the sufficient active sites to achieve superior biocatalytic performances. Besides, the Pd shell and Au core serve as storage layers providing abundant energetic charge carriers. The Ptc-PA exhibits a prominent peroxidase (POD)-like activity with the catalytic efficiency (Kcat/Km) of 1.50 × 109 mM-1 min-1, about four orders of magnitude higher than natural horseradish peroxidase (HRP), while catalase (CAT)-like and superoxide dismutase (SOD)-like activities of Ptc-PA are also comparable to those of natural enzymes. Biological experiments demonstrate that the detection limit of the Ptc-PA-based catalytic detection system exceeds that of visual inspection by 132-fold in clinical cancer diagnosis. Besides, Ptc-PA can reduce multi-organ acute inflammatory damage and mitigate oxidative stress disorder.

Nanoradiosensitizers in glioblastoma treatment: recent advances and future perspectives

Glioblastoma (GBM), a highly invasive type of brain tumor located within the central nervous system, manifests a median survival time of merely 14.6 months. Radiotherapy kills tumor cells through focused high-energy radiation and has become a crucial treatment strategy for GBM, especially in cases where surgical resection is not viable. However, the presence of radioresistant tumor cells limits its clinical effectiveness. Radioresistance is a key factor of treatment failure, prompting the development of various therapeutic strategies to overcome this challenge. With the rapid development of nanomedicine, nanoradiosensitizers provide a novel approach to enhancing the effectiveness of radiotherapy. In this review, we discuss the reasons behind GBM radio-resistance and the mechanisms of radiotherapy sensitization. Then we summarize the primary types of nanoradiosensitizers and recent progress in their application for the radiosensitization of GBM. Finally, we elucidate the factors influencing their practical implementation, along with the challenges and promising prospects associated with multifunctional nanoradiosensitizers.

Current status and prospects of MOFs loaded with H2O2-related substances for ferroptosis therapy

Ferroptosis is a programmed cell death mechanism characterized by the accumulation of iron (Fe)-dependent lipid peroxides within cells. Ferroptosis holds excellent promise in tumor therapy. Metal-organic frameworks (MOFs) offer unique advantages in tumor ferroptosis treatment due to their high porosity, excellent stability, high biocompatibility, and targeting capabilities. Inducing ferroptosis in tumor cells primarily involves the production of reactive oxygen species (ROS), like hydroxyl radicals (˙OH), through iron-mediated Fenton reactions. However, the intrinsic H2O2 levels in tumor cells are often insufficient to sustain prolonged consumption, limiting therapeutic efficacy if ˙OH production is inadequate. Therefore, catalyzing or supplementing the intracellular H2O2 levels in tumor cells is essential for inducing ferroptosis by nanoscale metal-organic frameworks. This article reviews the biological characteristics and molecular mechanisms of ferroptosis, introduces H2O2-related substances, and reviews MOF-based nanoscale strategies for enhancing intracellular H2O2 levels in tumor cells. Finally, the challenges and prospects of this approach are discussed, aiming to provide insights into improving the effectiveness of ferroptosis induced by MOFs.

The interplay between cytokines, inflammation, and antioxidants: mechanistic insights and therapeutic potentials of various antioxidants and anti-cytokine compounds

Cytokines regulate immune responses essential for maintaining immune homeostasis, as deregulated cytokine signaling can lead to detrimental outcomes, including inflammatory disorders. The antioxidants emerge as promising therapeutic agents because they mitigate oxidative stress and modulate inflammatory pathways. Antioxidants can potentially ameliorate inflammation-related disorders by counteracting excessive cytokine-mediated inflammatory responses. A comprehensive understanding of cytokine-mediated inflammatory pathways and the interplay with antioxidants is paramount for developing natural therapeutic agents targeting inflammation-related disorders and helping to improve clinical outcomes and enhance the quality of life for patients. Among these antioxidants, curcumin, vitamin C, vitamin D, propolis, allicin, and cinnamaldehyde have garnered attention for their anti-inflammatory properties and potential therapeutic benefits. This review highlights the interrelationship between cytokines-mediated disorders in various diseases and therapeutic approaches involving antioxidants.

Targeted RT study: results on early toxicity of targeted therapies and radiotherapy

PURPOSE/OBJECTIVE

Currently, there are few prospective data on the tolerability of combining targeted therapies (TT) with radiation therapy (RT). The objective of this prospective study was to assess the feasibility and toxicity of pairing RT with concurrent TT in cancer patients. The aim was to enhance the existing evidence base for the simultaneous administration of targeted substances together with radiotherapy.

METHODS

Prospective study enrollment was conducted at a single institution between March 1, 2020, and December 31, 2021, for all patients diagnosed with histologically confirmed cancer who underwent external beam radiotherapy in combination with targeted therapy. The study, known as the "targeted RT study," was registered in the German Clinical Trials Register under DRKS00026193. Systematic documentation of the toxicity profiles of different targeted therapies was performed, and the assessment of acute toxicity followed the guidelines of the National Cancer Institute Common Terminology Criteria for Adverse Events Version v5.0.

RESULTS

A total of 334 patients underwent 683 radiation therapy series. During the course of RT, 51 different TT substances were concurrently administered. External beam radiotherapy was employed for various anatomical sites. The combination of RT and concurrent TT administration was generally well tolerated, with no instances of severe acute toxicity observed. The most commonly reported toxicity was fatigue, ranging from mild to moderate Common Terminology Criteria for Adverse Events (CTCAE) °I-°III. Other frequently observed toxicities included dermatitis, dyspnea, dysphagia, and dry cough. No toxicity greater than moderate severity was recorded at any point. In only 32 patients (4.7% of evaluated RT series), the concurrent substance administration was discontinued due to side effects. However, these side effects did not exceed mild severity according to CTCAE, suggesting that discontinuation was a precautionary measure. Only one patient receiving Imatinib treatment experienced a severe CTCAE °III side effect, leading to discontinuation of the concurrent substance due to the sudden occurrence of melaena during RT.

CONCLUSION

In conclusion, the current study did not demonstrate a significant increase or additional toxicity when combining radiotherapy and concurrent targeted therapy. However, additional research is required to explore the specific toxicity profiles of the various substances that can be utilized in this context.

TRIAL REGISTRATION NUMBER

DRKS00026193. Date of registration 12/27/2022 (retrospectively registered).

Low-dose X-ray stimulated NO-releasing nanocomposites for closed-loop dual-mode cancer therapy

X-ray-excited photodynamic therapy (X-PDT) employs X-rays as an energy source, overcoming the light penetration limitations of traditional photodynamic therapy (PDT) but is constrained by high-energy radiation and the hypoxic tumor microenvironment. Low-dose X-ray-excited photodynamic therapy and reduction of mitochondrial oxygen consumption can serve as significant breakthroughs in overcoming these barriers. In this study, NaLuF4:Tb/Gd (15%/5%)@NaYF4 (ScNP) nanoparticles adsorbing the photosensitizer MC540 and loaded with α-(nitrate ester) acid (NEAA) were prepared as low X-ray dose triggered nano-scintillators. The final product obtained was NaLuF4:Tb/Gd (15%/5%)@NaYF4@mSiO2@MC540@NEAA (ScNP-MS@MC540@NEAA) nanocomposites, which exhibited intense green luminescence. X-PDT generates cytotoxic reactive oxygen species (ROS) with minimal ionizing radiation damage. Simultaneously, NEAA reacts with glutathione (GSH) to generate nitric oxide (NO) for gaseous treatment of the damaged mitochondrial respiratory chain to reduce oxygen consumption and alleviate hypoxia, enhancing the X-PDT efficacy and realizing a closed-loop treatment. The superoxide ions (˙O2-) can rapidly react with NO produced to form the highly cytotoxic reactive nitrogen species (RNS) peroxynitrite anion (ONOO-), which exhibits higher cytotoxicity compared to ROS. Furthermore, GSH scavenges toxic ROS and maintains the physiological function of tumor cells. It can induce cancer cell overoxidation and nitrosative stress. This work describes a low-dose X-ray-triggered X-PDT system with total radiation of 50 mGy, which involves GSH consumption, self-supplied NO, mitochondrial damage alleviation, and hypoxia relief to generate ROS and RNS, forming a closed-loop anti-hypoxia dual-mode system with synergistically enhanced anti-tumor effects, without significant biological side effects. It provides a promising platform for deep-seated tumor X-PDT with considerable application prospects.

Exploring the combined impact of cisplatin and copper-cysteamine nanoparticles through Chemoradiation: An in-vitro study

Copper-Cysteamine nanoparticles (Cu-Cy NPs) have emerged as promising radiosensitizers in cancer treatment. This study aims to investigate the combined therapeutic effect of these nanoparticles and cisplatin using a clinical linear accelerator to enhance the efficacy of chemoradiation therapy for cervical cancer. Following successful synthesis and characterization of Cu-Cy NPs, the cytotoxicity effect of these nanoparticles and cisplatin in various concentrations was evaluated on HeLa cancer cells, individually and in combination. Additionally, the radiobiological effects of these agents were investigated under a 6MV linear accelerator. At a concentration of 25 mg/L, Cu-Cy NPs displayed no significant cytotoxicity toward HeLa cancer cells. However, when combined with 2Gy X-ray irradiation at this concentration, the nanoparticles demonstrated a potent radiosensitizing effect. Notably, cell viability and migration rate in the combination group (Cu-Cy NPs + cisplatin + radiation) were significantly reduced compared to the radiation-alone group. Additionally, the combination treatment induced a significantly higher rate of apoptosis compared to the radiation-alone group. Overall, Cu-Cy NPs exhibited a significant dose-dependent synergistic enhancement of radiation efficacy when combined with cisplatin under X-ray exposure, and may provide a promising approach to improve the therapeutic effect of conventional radiation therapy.

Selenium-Doped Nanoheterojunctions for Highly Efficient Cancer Radiosensitization

Exploring efficient and low-toxicity radiosensitizers to break through the bottleneck of radiation tolerance, immunosuppression and poor prognosis remains one of the critical developmental challenges in radiotherapy. Nanoheterojunctions, due to their unique physicochemical properties, have demonstrated excellent radiosensitization effects in radiation energy deposition and in lifting tumor radiotherapy inhibition. Herein, they doped selenium (Se) into prussian blue (PB) to construct a nano-heterojunction (Se@PB), which could promote the increase of Fe2+/Fe3+ ratio and conversion of Se to a high valence state with Se introduction. The Fe2+-Se-Fe3+ electron transfer chain accelerates the rate of electron transfer on the surface of the nanoparticles, which in turn endows it with efficient X-ray energy transfer and electron transport capability, and enhances radiotherapy physical sensitivity. Furthermore, Se@PB induces glutathione (GSH) depletion and Fe2+ accumulation through pro-Fenton reaction, thereby disturbs the redox balance in tumor cells and enhances biochemical sensitivity of radiotherapy. As an excellent radiosensitizer, Se@PB effectively enhances X-ray induced mitochondrial dysfunction and DNA damage, thereby promotes cell apoptosis and synergistic cervical cancer radiotherapy. This study elucidates the radiosensitization mechanism of Se-doped nanoheterojunction from the perspective of the electron transfer chain and biochemistry reaction, which provides an efficient and low-toxic strategy in radiotherapy.

Additional considerations in cancer cell radioresistance, integrin αvβ3 and thyroid hormones

BACKGROUND

The existence of a functional relationship between a certain thyroid hormone analogue and cancer cell radioresistance has been shown by Leith and coworkers. The hormone analogue with relevance to malignant cells' radioresistance is tetraiodothyroacetic acid (tetrac). Tetrac is the deaminated derivative of L-thyroxine (T4), the principal product of the thyroid gland. Preclinical studies demonstrated that tetrac and chemically modified tetrac (CMT), e.g. a fluorobenzyl-conjugated tetrac analogue, restores radiosensitivity in certain radioresistant tumor cells. Due to their molecular, physico-chemical, and biological properties, actions of CMT analogues are believed to be initiated at the thyroid hormone analogue receptor site on plasma membrane integrin αvβ3.

OBJECTIVE

To explore possible molecular mechanisms of the potentially therapeutically beneficial effect of CMT on cancer cells' sensitivity to radiation, we analyzed actions of CMT analogues on expression of selected sets of genes that have been previously implicated in radioresistance of malignant cells.

DISCUSSION AND CONCLUSIONS

In the current study, we report that genome-wide gene expression profiling analysis of human glioblastoma (GBM) and acute myelocytic leukemia (AML) cell lines exposed in vitro to noncytotoxic doses of CMT has identified decreased expression of discrete trios of genes each of which was previously linked to cancer cells' radioresistance. Following the CMT treatment in AML cells, expression of PARP9, PARP15 and STAT3 genes was significantly reduced, while in GBM cells, expression of PRKDC, EGFR and CCNDI was significantly decreased by the drug. Notably, a broader spectrum of genes implicated in cancer cells' radioresistance was observed in primary patient-derived GBM cells after the CMT treatment. Extensive additional experimental and clinical studies are indicated, including analyses of individual patient tumor genomics and of an array of different tumor types to define the sub-sets of tumors manifesting radioresistance in which tetrac-based agents may be expected to enhance therapeutic effects of radiation.

Nano-Assisted Radiotherapy Strategies: New Opportunities for Treatment of Non-Small Cell Lung Cancer

Lung cancer is the second most commonly diagnosed cancer and a leading cause of cancer-related death, with non-small cell lung cancer (NSCLC) being the most prevalent type. Over 70% of lung cancer patients require radiotherapy (RT), which operates through direct and indirect mechanisms to treat cancer. However, RT can damage healthy tissues and encounter radiological resistance, making it crucial to enhance its precision to optimize treatment outcomes, minimize side effects, and overcome radioresistance. Integrating nanotechnology into RT presents a promising method to increase its efficacy. This review explores various nano-assisted RT strategies aimed at achieving precision treatment. These include using nanomaterials as radiosensitizers, applying nanotechnology to modify the tumor microenvironment, and employing nano-based radioprotectors and radiation-treated cell products for indirect cancer RT. We also explore recent advancements in nano-assisted RT for NSCLC, such as biomimetic targeting that alters mesenchymal stromal cells, magnetic targeting strategies, and nanosensitization with high-atomic number nanomaterials. Finally, we address the existing challenges and future directions of precision RT using nanotechnology, highlighting its potential clinical applications.

Phase-separated super-enhancers confer an innate radioresistance on genomic DNA

Recently, biomolecular condensates formed through liquid-liquid phase separation have been widely reported to regulate key intracellular processes involved in cell biology and pathogenesis. BRD4 is a nuclear protein instrumental to the establishment of phase-separated super-enhancers (SEs) to direct the transcription of important genes. We previously observed that protein droplets of BRD4 became hydrophobic as their size increase, implying an ability of SEs to limit the ionization of water molecules by irradiation. Here, we aim to establish if SEs confer radiation resistance in cancer cells. We established an in vitro DNA damage assay that measures the effect of radicals provoked by the Fenton reaction on DNA integrity. This revealed that DNA damage was markedly reduced when BRD4 underwent phase separation with DNA. Accordingly, co-focal imaging analyses revealed that SE foci and DNA damage foci are mutually exclusive in irradiated cells. Lastly, we observed that the radioresistance of cancer cells was significantly reduced when irradiation was combined with ARV-771, a BRD4 de-stabilizer. Our data revealed the existence of innately radioresistant genomic regions driven by phase separation in cancer cells. The disruption of these phase-separated components enfolding genomic DNA may represent a novel strategy to augment the effects of radiotherapy.

Evaluating deposited radiation energy amount and collision quantities of small-molecule radiosensitizers through Monte Carlo simulations

This study investigates the photon interaction mechanism of various small molecule radiosensitizers, including Hydrogen Peroxide, Nimorazole, 5-Fluorouracil, NVX-108, and others, using the MCNP 6.3 Monte Carlo simulation code. The simulations focused on quantifying the linear attenuation coefficients, mean free path, and accumulation factors of these radiosensitizers, as well as their interactions in a simulated spherical water phantom irradiated with a 100 keV mono-energetic X-ray source. Our findings reveal significant variations in deposited energy, collision events, and mean free path among the radiosensitizers, indicating different efficacy levels in enhancing radiation therapy. Notably, NVX-108 demonstrated the highest energy deposition, suggesting its potential as a highly effective radiosensitizer. The study also examined the individual attenuation properties of these radiosensitizers against energetic photons, with NVX-108 showing the highest attenuation coefficient and a shorter mean free path, further supporting its superior potential in effective radiosensitization. It can be concluded that NVX-108 has higher interaction tendency with the energetic photons comparing other small-molecules under investigation.

Gold nanoparticle-enhanced radiotherapy: Dependence of the macroscopic dose enhancement on the microscopic localization of the nanoparticles within the tumor vasculature

In gold nanoparticle-enhanced radiotherapy, intravenously administered nanoparticles tend to accumulate in the tumor tissue by means of the so-called permeability and retention effect and upon irradiation with x-rays, the nanoparticles release a secondary electron field that increases the absorbed dose that would otherwise be obtained from the interaction of the x-rays with tissue alone. The concentration of the nanoparticles in the tumor, number of nanoparticles per unit of mass, which determines the total absorbed dose imparted, can be measured via magnetic resonance or computed tomography images, usually with a resolution of several millimeters. Using a tumor vasculature model with a resolution of 500 nm, we show that for a given concentration of nanoparticles, the dose enhancement that occurs upon irradiation with x-rays greatly depends on whether the nanoparticles are confined to the tumor vasculature or have already extravasated into the surrounding tumor tissue. We show that, compared to the reference irradiation with no nanoparticles present in the tumor model, irradiation with the nanoparticles confined to the tumor vasculature, either in the bloodstream or attached to the inner blood vessel walls, results in a two to three-fold increase in the absorbed dose to the whole tumor model, with respect to an irradiation when the nanoparticles have already extravasated into the tumor tissue. Therefore, it is not enough to measure the concentration of the nanoparticles in a tumor, but the location of the nanoparticles within each volume element of a tumor, be it inside the vasculature or the tumor tissue, needs to be determined as well if an accurate estimation of the resultant absorbed dose distribution, a key element in the success of a radiotherapy treatment, is to be made.

Progression in low-intensity ultrasound-induced tumor radiosensitization

BACKGROUND

Radiotherapy (RT) is a widely utilized tumor treatment approach, while a significant obstacle in this treatment modality is the radioresistance exhibited by tumor cells. To enhance the effectiveness of RT, scientists have explored radiosensitization approaches, including the use of radiosensitizers and physical stimuli. Nevertheless, several approaches have exhibited disappointing results including adverse effects and limited efficacy. A safer and more effective method of radiosensitization involves low-intensity ultrasound (LIUS), which selectively targets tumor tissue and enhances the efficacy of radiation therapy.

METHODS

This review summarized the tumor radioresistance reasons and explored LIUS potential radiosensitization mechanisms. Moreover, it covered diverse LIUS application strategies in radiosensitization, including the use of LIUS alone, ultrasound-targeted intravascular microbubble destruction, ultrasound-mediated targeted radiosensitizers delivery, and sonodynamic therapy. Lastly, the review presented the limitations and prospects of employing LIUS-RT combined therapy in clinical settings, emphasizing the need to connect research findings with practical applications.

RESULTS AND CONCLUSION

LIUS employs cost-effective equipment to foster tumor radiosensitization, curtail radiation exposure, and elevate the quality of life for patients. This efficacy is attributed to LIUS's ability to utilize thermal, cavitation, and mechanical effects to overcome tumor cell resistance to RT. Multiple experimental analyses have underscored the effectiveness of LIUS in inducing tumor radiosensitization using diverse strategies. While initial studies have shown promising results, conducting more comprehensive clinical trials is crucial to confirm its safety and effectiveness in real-world situations.

A Dual-Channel Ca2+ Nanomodulator Induces Intracellular Ca2+ Disorders via Endogenous Ca2+ Redistribution for Tumor Radiosensitization

Tumor cells harness Ca2+ to maintain cellular homeostasis and withstand external stresses from various treatments. Here, a dual-channel Ca2+ nanomodulator (CAP-P-NO) is constructed that can induce irreversible intracellular Ca2+ disorders via the redistribution of tumor-inherent Ca2+ for disrupting cellular homeostasis and thus improving tumor radiosensitivity. Stimulated by tumor-overexpressed acid and glutathione, capsaicin and nitric oxide are successively escaped from CAP-P-NO to activate the transient receptor potential cation channel subfamily V member 1 and the ryanodine receptor for the influx of extracellular Ca2+ and the release of Ca2+ in the endoplasmic reticulum, respectively. The overwhelming level of Ca2+ in tumor cells not only impairs the function of organelles but also induces widespread changes in the gene transcriptome, including the downregulation of a set of radioresistance-associated genes. Combining CAP-P-NO treatment with radiotherapy achieves a significant suppression against both pancreatic and patient-derived hepatic tumors with negligible side effects. Together, the study provides a feasible approach for inducing tumor-specific intracellular Ca2+ overload via endogenous Ca2+ redistribution and demonstrates the great potential of Ca2+ disorder therapy in enhancing the sensitivity for tumor radiotherapy.

Diagnosis and treatment status of inoperable locally advanced breast cancer and the application value of inorganic nanomaterials

Locally advanced breast cancer (LABC) is a heterogeneous group of breast cancer that accounts for 10-30% of breast cancer cases. Despite the ongoing development of current treatment methods, LABC remains a severe and complex public health concern around the world, thus prompting the urgent requirement for innovative diagnosis and treatment strategies. The primary treatment challenges are inoperable clinical status and ineffective local control methods. With the rapid advancement of nanotechnology, inorganic nanoparticles (INPs) exhibit a potential application prospect in diagnosing and treating breast cancer. Due to the unique inherent characteristics of INPs, different functions can be performed via appropriate modifications and constructions, thus making them suitable for different imaging technology strategies and treatment schemes. INPs can improve the efficacy of conventional local radiotherapy treatment. In the face of inoperable LABC, INPs have proposed new local therapeutic methods and fostered the evolution of novel strategies such as photothermal and photodynamic therapy, magnetothermal therapy, sonodynamic therapy, and multifunctional inorganic nanoplatform. This article reviews the advances of INPs in local accurate imaging and breast cancer treatment and offers insights to overcome the existing clinical difficulties in LABC management.

Exploring Extravasation in Cancer Patients

Extravasation, the unintended leakage of intravenously administered substances, poses significant challenges in cancer treatment, particularly during chemotherapy and radiotherapy. This comprehensive review explores the pathophysiology, incidence, risk factors, clinical presentation, diagnosis, prevention strategies, management approaches, complications, and long-term effects of extravasation in cancer patients. It also outlines future directions and research opportunities, including identifying gaps in the current knowledge and proposing areas for further investigation in extravasation prevention and management. Emerging technologies and therapies with the potential to improve extravasation prevention and management in both chemotherapy and radiotherapy are highlighted. Such innovations include advanced vein visualization technologies, smart catheters, targeted drug delivery systems, novel topical treatments, and artificial intelligence-based image analysis. By addressing these aspects, this review not only provides healthcare professionals with insights to enhance patient safety and optimize clinical practice but also underscores the importance of ongoing research and innovation in improving outcomes for cancer patients experiencing extravasation events.

Sensitize Tumor Immunotherapy: Immunogenic Cell Death Inducing Nanosystems

Low immunogenicity of tumors poses a challenge in the development of effective tumor immunotherapy. However, emerging evidence suggests that certain therapeutic approaches, such as chemotherapy, radiotherapy, and phototherapy, can induce varying degrees of immunogenic cell death (ICD). This ICD phenomenon leads to the release of tumor antigens and the maturation of dendritic cells (DCs), thereby enhancing tumor immunogenicity and promoting immune responses. However, the use of a single conventional ICD inducer often fails to achieve in situ tumor ablation and establish long-term anti-tumor immune responses. Furthermore, the induction of ICD induction varies among different approaches, and the distribution of the therapeutic agent within the body influences the level of ICD and the occurrence of toxic side effects. To address these challenges and further boost tumor immunity, researchers have explored nanosystems as inducers of ICD in combination with tumor immunotherapy. This review examines the mechanisms of ICD and different induction methods, with a specific focus on the relationship between ICD and tumor immunity. The aim is to explore the research advancements utilizing various nanomaterials to enhance the body's anti-tumor effects by inducing ICD. This paper aims to contribute to the development and clinical application of nanomaterial-based ICD inducers in the field of cancer immunotherapy by providing important theoretical guidance and practical references.

Photothermal and radiotherapy with alginate-coated gold nanoparticles for breast cancer treatment

Radiation therapy and phototherapy are commonly used cancer treatments that offer advantages such as a low risk of adverse effects and the ability to target cancer cells while sparing healthy tissue. A promising strategy for cancer treatment involves using nanoparticles (NPs) in combination with radiation and photothermal therapy to target cancer cells and improve treatment efficacy. The synthesis of gold NPs (AuNPs) for use in biomedical applications has traditionally involved toxic reducing agents. Here we harnessed dopamine (DA)-conjugated alginate (Alg) for the facile and green synthesis of Au NPs (Au@Alg-DA NPs). Alg-DA conjugate reduced Au ions, simultaneously stabilized the resulting AuNPs, and prevented aggregation, resulting in particles with a narrow size distribution and improved stability. Injectable Au@Alg-DA NPs significantly promoted ROS generation in 4T1 breast cancer cells when exposed to X-rays. In addition, their administration raised the temperature under a light excitation of 808 nm, thus helping to destroy cancer cells more effectively. Importantly, no substantial cytotoxicity was detected in our Au@Alg-DA NPs. Taken together, our work provides a promising route to obtain an injectable combined radio enhancer and photothermally active nanosystem for further potential clinic translation.

Targeting mTOR and survivin concurrently potentiates radiation therapy in renal cell carcinoma by suppressing DNA damage repair and amplifying mitotic catastrophe

BACKGROUND

Renal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.

EXPERIMENTAL DESIGN

We slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.

RESULTS

EY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.

CONCLUSION

Taken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.