Modern Brachytherapy

Mesenchymal stem cell-derived exosomes for management of prostate cancer: An updated view

Prostate cancer represents the second most prevalent form of cancer found in males, and stands as the fifth primary contributor to cancer-induced mortality on a global scale. Research has shown that transplanted mesenchymal stem cells (MSCs) can migrate by homing to tumor sites in the body. In prostate cancer, researchers have explored the fact that MSC-based therapies (including genetically modified delivery vehicles or vectors) and MSC-derived exosomes are emerging as attractive options to improve the efficacy and safety of traditional cancer therapies. In addition, researchers have reported new insights into the application of extracellular vesicle (EV)-MSC therapy as a novel treatment option that could provide a more effective and targeted approach to prostate cancer treatment. Moreover, the new generation of exosomes, which contain biologically functional molecules as signal transducers between cells, can simultaneously deliver different therapeutic agents and induce an anti-tumor phenotype in immune cells and their recruitment to the tumor site. The results of the current research on the use of MSCs in the treatment of prostate cancer may be helpful to researchers and clinicians working in this field. Nevertheless, it is crucial to emphasize that although dual-role MSCs show promise as a therapeutic modality for managing prostate cancer, further investigation is imperative to comprehensively grasp their safety and effectiveness. Ongoing clinical trials are being conducted to assess the viability of MSCs in the management of prostate cancer. The results of these trials will help determine the viability of this approach. Based on the current literature, engineered MSCs-EV offer great potential for application in targeted tumor therapy.

Previous external beam radiation therapy for pelvic malignancy increases complications of total hip arthroplasty

INTRODUCTION

External beam radiation therapy (EBRT) has known effects on bone health. No large database studies have looked at the effects of pelvic EBRT on total hip arthroplasty (THA) outcomes. The purpose of this study was to evaluate 90-day and long-term (>2 years) complication rates following THA in patients with a history of pelvic malignancy and EBRT.

METHODS

Patients were retrospectively identified using a national insurance claims database. Subjects who underwent THA for osteoarthritis or avascular necrosis were included if they had at least 2-year follow-up and were stratified into 3 cohorts: (1) prior pelvic malignancy diagnosis (prostate, cervical, uterine, ovarian, or rectal) and EBRT (Group A); (2) prior malignancy diagnosis but no EBRT (Group B); and (3) neither prior malignancy diagnosis nor EBRT (Group C). Univariate and multivariate analyses were conducted to evaluate for an association between prior EBRT and the incidence of 90-day and 2-year complication rates using chi-square, student t-tests, and logistic regression analyses where appropriate.

RESULTS

671,554 patients met the inclusion criteria. Group A had higher odds of all-cause revision, septic revision, and loosening with revision after 2 years when compared to Group C and Group B (p < 0.001). Group A subjects had higher rates of 90-day deep vein thrombosis, sepsis, and stroke (p < 0.001) than groups B and C.

CONCLUSIONS

Prior EBRT for pelvic malignancy was associated with significantly increased rates of all-cause revision, septic revision, and loosening as well as 90-day medical complications.

Tailoring the AIE Chromogen 2-(2-Hydroxyphenyl)benzothiazole for Use in Enzyme-Triggered Molecular Brachytherapy

A targeted strategy for treating cancer is antibody-directed enzyme prodrug therapy, where the enzyme attached to the antibody causes conversion of an inactive small-molecule prodrug into an active drug. A limitation may be the diffusion of the active drug away from the antibody target site. A related strategy with radiotherapeutics entails enzymatically promoted conversion of a soluble to insoluble radiotherapeutic agent, thereby immobilizing the latter at the target site. Such a molecular brachytherapy has been scarcely investigated. In distinct research, the advent of molecular designs for aggregation-induced emission (AIE) suggests translational use in molecular brachytherapy. Here, several 2-(2-hydroxyphenyl)benzothiazole substrates that readily aggregate in aqueous solution (and afford AIE) were elaborated in this regard. In particular, (1) the 2-(2-hydroxyphenyl) unit was derivatized to bear a pegylated phosphodiester that imparts water solubility yet undergoes enzymatic cleavage, and (2) a p-phenol unit was attached to the benzo moiety to provide a reactive site for final-step iodination (here examined with natural abundance iodide). The pegylated phosphodiester-iodinated benzothiazole undergoes conversion from aqueous-soluble to aqueous-insoluble upon treatment with a phosphatase or phosphodiesterase. The aggregation is essential to molecular brachytherapy, whereas the induced emission of AIE is not essential but provides a convenient basis for research development. Altogether, 21 compounds were synthesized (18 new, 3 known via new routes). Taken together, blending biomedical strategies of enzyme prodrug therapy with materials chemistry concerning substances that undergo AIE may comprise a step forward on the long road toward molecular brachytherapy.

Radiation in Gastroenterology

The benefit of radiation is immense in the field of gastroenterology. Radiation is used daily in different gastrointestinal imaging and diagnostic and therapeutic interventional procedures. Radiotherapy is one of the primary modalities of treatment of gastrointestinal malignancies. There are various modalities of radiotherapy. Radiotherapy can injure malignant cells by directly damaging DNA, RNA, proteins, and lipids and indirectly by forming free radicals. External beam radiation, internal beam radiation and radio-isotope therapy are the major ways of delivering radiation to the malignant tissue. Radiation can also cause inflammation, fibrosis, organ dysfunction, and malignancy. Patients with repeated exposure to radiation for diagnostic imaging and therapeutic procedures are at slightly increased risk of malignancy. Gastrointestinal endoscopists performing fluoroscopy-guided procedures are also at increased risk of malignancy and cataract formation. The radiological protection society recommends certain preventive and protective measures to avoid side effects of radiation. Gastrointestinal complications related to radiation therapy for oncologic processes, and exposure risks for patients and health care providers involved in diagnostic or therapeutic imaging will be discussed in this review.

Cardiac complications of cancer therapies

The quest of defeating cancer and improving prognosis in survivors has generated remarkable strides forward in research and have advanced the development of new antineoplastic therapies. These achievements, combined with rapid screening and early detection, have considerably extended the life expectancy of patients surviving multiple types of malignancies. Consequently, chemotherapy-related toxicity in several organ systems, especially the cardiovascular system, has surfaced as one of the leading causes of morbidity and mortality among cancer survivors. Recent evidence classifies chemotherapy-induced cardiotoxicity as the second-leading cause of morbidity and mortality, closely comparing with secondary cancer malignancies. While a certain degree of cardiotoxicity has been reported to accompany most chemotherapies, including anthracyclines, anti-metabolites, and alkylating agents, even the latest targeted cancer therapies such as immune checkpoint inhibitors and tyrosine kinase inhibitors have been associated with acute and chronic cardiac sequelae. In this chapter, we focus on describing the principal mechanism(s) for each class of chemotherapeutic agents that lead to cardiotoxicity and the innovative translational research approaches that are currently being explored to prevent or treat cancer therapy-induced cardiotoxicity and related cardiac complications.

Pediatric primary cutaneous anaplastic large cell lymphoma treated with brachytherapy

Primary cutaneous anaplastic large cell lymphoma (PC-ALCL) is a CD30+ lymphoproliferative disorder that rarely occurs in children. Although there are currently no consensus guidelines for the treatment of cutaneous lymphoma in the pediatric population, the isolated form of PC-ALCL is typically managed by surgical excision or external beam radiation therapy. We report the case of a 6-year-old girl with primary cutaneous anaplastic large cell lymphoma that was treated with brachytherapy with no recurrence after 21 months of follow-up, suggesting that brachytherapy may be considered as a treatment for pediatric cutaneous large cell anaplastic lymphoma.

Exploiting DNA repair pathways for tumor sensitization, mitigation of resistance, and normal tissue protection in radiotherapy

More than half of cancer patients are treated with radiotherapy, which kills tumor cells by directly and indirectly inducing DNA damage, including cytotoxic DNA double-strand breaks (DSBs). Tumor cells respond to these threats by activating a complex signaling network termed the DNA damage response (DDR). The DDR arrests the cell cycle, upregulates DNA repair, and triggers apoptosis when damage is excessive. The DDR signaling and DNA repair pathways are fertile terrain for therapeutic intervention. This review highlights strategies to improve therapeutic gain by targeting DDR and DNA repair pathways to radiosensitize tumor cells, overcome intrinsic and acquired tumor radioresistance, and protect normal tissue. Many biological and environmental factors determine tumor and normal cell responses to ionizing radiation and genotoxic chemotherapeutics. These include cell type and cell cycle phase distribution; tissue/tumor microenvironment and oxygen levels; DNA damage load and quality; DNA repair capacity; and susceptibility to apoptosis or other active or passive cell death pathways. We provide an overview of radiobiological parameters associated with X-ray, proton, and carbon ion radiotherapy; DNA repair and DNA damage signaling pathways; and other factors that regulate tumor and normal cell responses to radiation. We then focus on recent studies exploiting DSB repair pathways to enhance radiotherapy therapeutic gain.

Engineering of an archaeal phosphodiesterase to trigger aggregation-induced emission (AIE) of synthetic substrates

Aggregation-induced emission (AIE) probes that can be triggered by enzymatic activity are valuable for applications across the life sciences.