Emerging biomedical imaging-based companion diagnostics for precision medicine

Activatable Chemodynamic Theranostics through Molecular Imaging-Energized Companion Diagnostics

Chemodynamic therapy (CDT) is a promising tumor treatment strategy, yet real-time in vivo monitoring remains challenging. Here, we report an activatable molecular imaging-energized companion diagnostics sensor (CFG) for real-time monitoring of CDT. CFG leverages glucose oxidase (GOx) to generate hydrogen peroxide to prime the Fenton reaction, while simultaneously producing H+ to activate the fluorescence (FL) and photoacoustic (PA) signals. A positive correlation between the FL/PA intensities and the Fenton reaction efficiency is found (Pearson's r = 0.98 for ·OH-FL, 0.90 for ·OH-PA), enabling dynamic visualization of the GOx catalysis-primed CDT. Also, H+-activated photothermal effect of CFG enables FL/PA imaging to pinpoint the optimal irradiation time for maximizing mild hyperthermia-enhanced CDT. Therefore, by tracing the H+ dynamics, tailored feedback is collected for therapeutic response monitoring and treatment guidance, and the cascade effect between enzyme catalysis, mild hyperthermia, and CDT is revealed.

A biorthogonal chemistry approach for high-contrast antibody imaging of lymphoma at early time points

BACKGROUND

Monoclonal antibodies are highly specific for their targets making them effective for cancer therapy. However, their large molecular weight causes slow blood clearance, often requiring weeks to be removed from circulation. This limitation affects companion nuclear imaging and antibody-based diagnostics, necessitating delayed imaging. We report the expansion of a methodology improving positron emission tomography (PET) contrast of the lymphoma biomarker CD20 at early time points after radiolabeled antibody administration. Intact radioimmunoconjugates are allowed to stay in circulation long enough to accumulate in tumors, and then, using a chemical trigger, we induced rapid clearance of the radioactivity from non-target tissues by cleaving the linker between the antibody and the radioactivity. For brevity, we refer to the this as the Tetrazine KnockOut (TKO) method which uses the transcyclooctene-tetrazine (TCO-Tz) reaction, wherein an antibody is conjugated with linker containing TCO and a radioisotope.

RESULTS

We optimized the TCO linker with several different radioisotopes and evaluated the ability of tetrazines to knockout radioactivity from circulating antibodies. We explored several cell types and antibodies with varying internalization rates, to characterize the parameters of TKO and tested [89Zr]Zr-DFO-TCO-rituximab in a lymphoma model with PET imaging after Tz or vehicle administration. Treatment with Tz induced > 70% cleavage of the TCO linker in vitro within 30 min. Internalizing radioimmunoconjugates exhibited similar cellular uptake with Tz compared to vehicle, whereas decreased uptake was seen with slowly internalizing antibodies. In rodents, Tz rapidly liberated the radioactivity from the antibody, cleared from the blood, and accumulated in the bladder. TKO resulted in > 50% decreased radioactivity in non-target organs following Tz injection. No decrease in tumor uptake was observed when rate of antibody internalization is higher in a lymphoma model, and the target-to-background ratio increased by > twofold in comparison with Tz nontreated groups at 24 h.

CONCLUSION

The TKO approach potentiates early imaging of rituximab radioimmunoconjugates and has translational potential for lymphoma imaging.

Nanomaterials exert biological effects by influencing the ubiquitin-proteasome system

The ubiquitin-proteasome system (UPS) is an important type of protein post-translational modification that affects the quantity and quality of various proteins and influences cellular processes such as the cell cycle, transcription, oxidative stress, and autophagy. Nanomaterials (NMs), which exhibit excellent physicochemical properties, can directly interact with the UPS and act as molecular-targeted drugs to induce changes in biological processes. This review provides an overview of the influence of NMs on the UPS of misfolded proteins and key proteins, which are related to cancer, neurodegenerative diseases and oxidative stress. This review also summarizes the role of modification processes involved in ubiquitination the biological effects of NMs and the mechanism of such effects of NMs through regulation of the UPS. This review deepens our understanding of the influence of NMs on the protein degradation process and provides new potential therapeutic targets for disease.

Self-Activated Cascade-Tailored Small Molecule for Cancer Therapy, Companion Diagnostics, and "Theranostic Correlation" Evaluation

Companion diagnostics (CDx) have emerged as valuable tools for monitoring biomarkers essential for drug activation and therapeutic response, enabling personalized treatment strategies. However, the current FDA-approved CDx is limited to in vitro testing, making it challenging to assess the real-time drug efficacy. Moreover, evaluation of treatment responses solely based on drug release or activation may disregard tumor heterogeneity. To address these challenges, we have developed a cascade-responsive small molecule Cbl-DEVD-Hcy for simultaneous cancer therapy and the timely evaluation of therapy effectiveness in vivo. Upon cleavage by tumor-cell-overexpressed carboxylesterase, chlorambucil (Cbl) can be released to induce tumor cell apoptosis and activate caspase-3. This activation triggers the production of the near-infrared dye Hcy-NH2, generating both near-infrared fluorescence and photoacoustic signals for monitoring the apoptosis process. The excellent "theranostic correlation" between the imaging signal and therapeutic response, as demonstrated in orthotopic breast tumors, highlights the potential of Cbl-DEVD-Hcy for effective tumor therapy and precise CDx in the body.

Ultrathin Gd-Oxide Nanosheet as Ultrasensitive Companion Diagnostic Tool for MR Imaging and Therapy of Submillimeter Microhepatocellular Carcinoma

Early stage hepatocellular carcinoma (HCC) presents a formidable challenge in clinical settings due to its asymptomatic progression and the limitations of current imaging techniques in detecting micro-HCC lesions. Addressing this critical issue, we introduce a novel ultrathin gadolinium-oxide (Gd-oxide) nanosheet-based platform with heightened sensitivity for high-field MRI and as a therapeutic agent for HCC. Synthesized via a digestive ripening process, these Gd-oxide nanosheets exhibit an exceptional acid-responsive profile. The integration of the ultrathin Gd-oxide with an acid-responsive polymer creates an ultrasensitive high-field MRI probe, enabling the visualization of submillimeter-sized tumors with superior sensitivity. Our research underscores the ultrasensitive probe's efficacy in the treatment of orthotopic HCC. Notably, the ultrasensitive probe functions dually as a companion diagnostic tool, facilitating simultaneous imaging and therapy with real-time treatment monitoring capabilities. In conclusion, this study showcases an innovative companion diagnostic tool that holds promise for the early detection and effective treatment of micro-HCC.

Imaging-guided companion diagnostics in radiotherapy by monitoring APE1 activity with afterglow and MRI imaging

Companion diagnostics using biomarkers have gained prominence in guiding radiotherapy. However, biopsy-based techniques fail to account for real-time variations in target response and tumor heterogeneity. Herein, we design an activated afterglow/MRI probe as a companion diagnostics tool for dynamically assessing biomarker apurinic/apyrimidinic endonuclease 1(APE1) during radiotherapy in vivo. We employ ultrabright afterglow nanoparticles and ultrasmall FeMnOx nanoparticles as dual contrast agents, significantly broadening signal change range and enhancing the sensitivity of APE1 imaging (limit of detection: 0.0092 U/mL in afterglow imaging and 0.16 U/mL in MRI). We devise longitudinally and transversely subtraction-enhanced imaging (L&T-SEI) strategy to markedly enhance MRI contrast and signal-to-noise ratio between tumor and normal tissue of living female mice. The combined afterglow and MRI facilitate both anatomical and functional imaging of APE1 activity. This probe enables correlation of afterglow and MRI signals with APE1 expression, radiation dosage, intratumor ROS, and DNA damage, enabling early prediction of radiotherapy outcomes (as early as 3 h), significantly preceding tumor size reduction (6 days). By monitoring APE1 levels, this probe allows for early and sensitive detection of liver organ injury, outperforming histopathological analysis. Furthermore, MRI evaluates APE1 expression in radiation-induced abscopal effects provides insights into underlying mechanisms, and supports the development of treatment protocols.

Functional Imaging in Musculoskeletal Disorders in Menopause

Menopause-related musculoskeletal (MSK) disorders include osteoporosis, osteoarthritis (OA), sarcopenia and sarco-obesity. This review focuses on the applications of nuclear medicine for the functional imaging of the aforementioned clinical conditions. Bone Scan (BS) with 99mTc-labeled phosphonates, alone or in combination with MRI, can identify "fresh" vertebral collapse due to age-associated osteoporosis and provides quantitative parameters characterized by a good correlation with radiological indices in patients with OA. 18F-NaF PET, particularly when performed by dynamic scan, has given encouraging results for measuring bone turnover in osteoporosis and allows the evaluation of subchondral bone metabolic activity in OA. FDG PET can help discriminate between pathological and nonpathological vertebral fractures, especially by applying appropriate SUV-based thresholds. In OA, it can effectively image inflamed joints and support appropriate clinical management. Preliminary evidences suggest a possible application of FDG in sarco-obesity for the detection and quantification of visceral adipose tissue (VAT). Further studies are needed to better define the role of nuclear medicine in menopause-related MSK disease, especially as regards the possible impact of new radiopharmaceuticals (ie, FAPI and RGD peptides) and recent technological advances (eg, total-body PET/CT scanners).

Drug Selection and Posology, Optimal Therapies and Risk/Benefit Assessment in Medicine: The Paradigm of Iron-Chelating Drugs

The design of clinical protocols and the selection of drugs with appropriate posology are critical parameters for therapeutic outcomes. Optimal therapeutic protocols could ideally be designed in all diseases including for millions of patients affected by excess iron deposition (EID) toxicity based on personalised medicine parameters, as well as many variations and limitations. EID is an adverse prognostic factor for all diseases and especially for millions of chronically red-blood-cell-transfused patients. Differences in iron chelation therapy posology cause disappointing results in neurodegenerative diseases at low doses, but lifesaving outcomes in thalassemia major (TM) when using higher doses. In particular, the transformation of TM from a fatal to a chronic disease has been achieved using effective doses of oral deferiprone (L1), which improved compliance and cleared excess toxic iron from the heart associated with increased mortality in TM. Furthermore, effective L1 and L1/deferoxamine combination posology resulted in the complete elimination of EID and the maintenance of normal iron store levels in TM. The selection of effective chelation protocols has been monitored by MRI T2* diagnosis for EID levels in different organs. Millions of other iron-loaded patients with sickle cell anemia, myelodysplasia and haemopoietic stem cell transplantation, or non-iron-loaded categories with EID in different organs could also benefit from such chelation therapy advances. Drawbacks of chelation therapy include drug toxicity in some patients and also the wide use of suboptimal chelation protocols, resulting in ineffective therapies. Drug metabolic effects, and interactions with other metals, drugs and dietary molecules also affected iron chelation therapy. Drug selection and the identification of effective or optimal dose protocols are essential for positive therapeutic outcomes in the use of chelating drugs in TM and other iron-loaded and non-iron-loaded conditions, as well as general iron toxicity.