Current progress, strategy, and prospects of PD-1/PDL-1 immune checkpoint biosensing platforms for cancer diagnostics, therapy monitoring, and drug screening

Smart delivery vehicles for cancer: categories, unique roles and therapeutic strategies

Chemotherapy and surgery remain the primary treatment modalities for cancers; however, these techniques have drawbacks, such as cancer recurrence and toxic side effects, necessitating more efficient cancer treatment strategies. Recent advancements in research and medical technology have provided novel insights and expanded our understanding of cancer development; consequently, scholars have investigated several delivery vehicles for cancer therapy to improve the efficiency of cancer treatment and patient outcomes. Herein, we summarize several types of smart therapeutic carriers and elaborate on the mechanism underlying drug delivery. We reveal the advantages of smart therapeutic carriers for cancer treatment, focus on their effectiveness in cancer immunotherapy, and discuss the application of smart cancer therapy vehicles in combination with other emerging therapeutic strategies for cancer treatment. Finally, we summarize the bottlenecks encountered in the development of smart cancer therapeutic vehicles and suggest directions for future research. This review will promote progress in smart cancer therapy and facilitate related research.

The opportunities and challenges of using PD-1/PD-L1 inhibitors for leukemia treatment

Leukemia poses a significant clinical challenge due to its swift onset, rapid progression, and treatment-related complications. Tumor immune evasion, facilitated by immune checkpoints like programmed death receptor 1/programmed death receptor ligand 1 (PD-1/PD-L1), plays a critical role in leukemia pathogenesis and progression. In this review, we summarized the research progress and therapeutic potential of PD-L1 in leukemia, focusing on targeted therapy and immunotherapy. Recent clinical trials have demonstrated promising outcomes with PD-L1 inhibitors, highlighting their role in enhancing treatment efficacy. This review discusses the implications of PD-L1 expression levels on treatment response and long-term survival rates in leukemia patients. Furthermore, we address the challenges and opportunities in immunotherapy, emphasizing the need for personalized approaches and combination therapies to optimize PD-L1 inhibition in leukemia management. Future research prospects include exploring novel treatment strategies and addressing immune-related adverse events to improve clinical outcomes in leukemia. Overall, this review provides valuable insights into the role of PD-L1 in leukemia and its potential as a therapeutic target in the evolving landscape of leukemia treatment.

Extracellular vesicle surface display of αPD-L1 and αCD3 antibodies via engineered late domain-based scaffold to activate T-cell anti-tumor immunity

Extracellular vesicles (EVs) are emerging as promising carriers for the delivery of therapeutic biologics. Genetic engineering represents a robust strategy for loading proteins of interest into EVs. Identification of EV-enriched proteins facilitates protein cargo loading efficiency. Many EV-enriched proteins are sorted into EVs via an endosomal sorting complex required for transport (ESCRT)-dependent pathway. In parallel, viruses hijack this EV biosynthesis machinery via conserved late domain motifs to promote egress from host cells. Inspired by the similarity of biogenesis between EVs and viruses, we developed a synthetic, Late domain-based EV scaffold protein that enables the display of a set of single chain variable fragments (scFvs) on the EV surface. We named this scaffold the Late domain-based exosomal antibody surface display platform (LEAP). We applied the LEAP scaffold to reprogramme HEK293T cell-derived EVs to elicit T-cell anti-tumor immunity by simultaneously displaying αPD-L1 and αCD3 scFvs on the EV surface (denoted as αPD-L1×αCD3 bispecific T-cell engaging exosomes, BiTExos). We demonstrated that αPD-L1×αCD3 BiTExos actively redirected T cells to bind to PD-L1+ tumor cells, promoting T-cell activation, proliferation and tumoricidal cytokine production. Furthermore, the αPD-L1×αCD3 BiTExos promoted T-cell infiltration into the tumor microenvironment to mitigate the tumor burden in vivo. Our study suggested that the LEAP scaffold may serve as a platform for EV surface display and could be applied for a broad range of EV-based biomedical applications.

Polymer-Based Terbium Complex as a Fluorescent Probe for Cancer Antigen 125 Detection: A Promising Tool for Early Diagnosis of Ovarian Cancer

A novel photoprobe, Tb-acetylacetone (Tb-ACAC) doped within a modified epoxy cellulose polymer immobilized with CA-125 monoclonal antibody, offers an accurate and highly selective method for early ovarian cancer (OC) diagnosis by detecting cancer antigen 125 (CA-125) in serum samples. This approach leverages quenching of the Tb-ACAC luminescence upon binding to CA-125. Characterization of the photoprobe film through UV-vis and fluorescence measurements confirmed the presence of Tb-ACAC within the polymer matrix. In aqueous solution (pH 6.8, λex = 365 nm), the characteristic emission band of Tb-ACAC at λem = 546.2 nm exhibited significant quenching upon CA-125 binding. This quenching effect enabled the sensitive and specific detection of CA-125 in diverse serum samples from OC patients, demonstrating the applicability, simplicity, and effectiveness of this novel approach.

Construction and Application of a PD-L1-Targeted Multimodal Diagnostic and Dual-Functional Theranostics Nanoprobe

Background

In recent years, PD-L1 has been primarily utilized as an immune checkpoint marker in cancer immunotherapy. However, due to tumor heterogeneity, the response rate to such therapies often falls short of expectations. In addition to its role in immunotherapy, PD-L1 serves as a specific target on the surface of tumor cells for targeted diagnostic and therapeutic interventions. There is an absence of a fully developed PD-L1-targeted diagnostic and therapeutic probe for clinical use, which constrains the exploration and clinical exploitation of this target.

Methods and Results

In this study, we engineered a PD-L1-targeted probe with multimodal imaging and dual therapeutic functionalities utilizing organic melanin nanoparticles. Functionalization with the WL12-SH peptide endowed the nanoprobe with specific targeting capabilities. Subsequent radiolabeling with 89Zr (half-life: 100.8 hours) and chelation of Mn2+ ions afforded the probe the capacity for simultaneous PET and MRI imaging modalities. Cellular uptake assays revealed pronounced specificity, with -positive cells exhibiting significantly higher uptake than -negative counterparts (p < 0.05). Dual-modal PET/MRI imaging delineated rapid and sustained accumulation at the neoplastic site, yielding tumor-to-non-tumor (T/NT) signal ratios at 24 hours post-injection of 16.67±3.45 for PET and 6.63±0.64 for MRI, respectively. We conjugated the therapeutic radionuclide 131I (half-life: 8.02 days) to the construct and combined low-dose radiotherapy and photothermal treatment (PTT), culminating in superior antitumor efficacy while preserving a high safety profile. The tumors in the cohort receiving the dual-modality therapy exhibited significantly reduced volume and weight compared to those in the control and monotherapy groups.

Conclusion

We developed and applied a novel -targeted multimodal theranostic nanoprobe, characterized by its high specificity and superior imaging capabilities as demonstrated in PET/MRI modalities. Furthermore, this nanoprobe facilitates potent therapeutic efficacy at lower radionuclide doses when used in conjunction with PTT.

Recent advances in understanding the immune microenvironment in ovarian cancer

The occurrence of ovarian cancer (OC) is a major factor in women's mortality rates. Despite progress in medical treatments, like new drugs targeting homologous recombination deficiency, survival rates for OC patients are still not ideal. The tumor microenvironment (TME) includes cancer cells, fibroblasts linked to cancer (CAFs), immune-inflammatory cells, and the substances these cells secrete, along with non-cellular components in the extracellular matrix (ECM). First, the TME mainly plays a role in inhibiting tumor growth and protecting normal cell survival. As tumors progress, the TME gradually becomes a place to promote tumor cell progression. Immune cells in the TME have attracted much attention as targets for immunotherapy. Immune checkpoint inhibitor (ICI) therapy has the potential to regulate the TME, suppressing factors that facilitate tumor advancement, reactivating immune cells, managing tumor growth, and extending the survival of patients with advanced cancer. This review presents an outline of current studies on the distinct cellular elements within the OC TME, detailing their main functions and possible signaling pathways. Additionally, we examine immunotherapy rechallenge in OC, with a specific emphasis on the biological reasons behind resistance to ICIs.

Bioengineering approaches for the endometrial research and application

The endometrium undergoes a series of precise monthly changes under the regulation of dynamic levels of ovarian hormones that are characterized by repeated shedding and subsequent regeneration without scarring. This provides the potential for wound healing during endometrial injuries. Bioengineering materials highlight the faithful replication of constitutive cells and the extracellular matrix that simulates the physical and biomechanical properties of the endometrium to a larger extent. Significant progress has been made in this field, and functional endometrial tissue bioengineering allows an in-depth investigation of regulatory factors for endometrial and myometrial defects in vitro and provides highly therapeutic methods to alleviate obstetric and gynecological complications. However, much remains to be learned about the latest progress in the application of bioengineering technologies to the human endometrium. Here, we summarize the existing developments in biomaterials and bioengineering models for endometrial regeneration and improving the female reproductive potential.

One-step and label-free ratiometric fluorescence assay for the detection of plasma exosome towards cancer diagnosis

Exosomes are closely associated with tumor development and are regarded as viable biomarkers for cancer. Here, a ratiometric fluorescence method was proposed for the one-step and label-free detection of plasma exosomes. A bicolor streptavidin magnetic beads were specifically created with an immobilized Cy5-labeled hairpin aptamer for CD63 (Cy5-Apt) on its surface to identify exosome, and a green color SYBR Green I (SGI) embedded in the stem of Cy5-Apt to respond to exosomes. After exosome capture, the Cy5-Apt could undergo a conformational shift and release the encapsulated SGI, allowing exosome measurement based on the fluorescence ratio of Cy5 and SGI. The enrichment, separation and detection of exosomes in proposed method could be completed in one step (30 min), which is a significant improvement over previous method. Furthermore, the use of ratiometric fluorescence and magnetic separation allows for exosome enrichment and interference elimination from complex matrices, improving accuracy and sensitivity. Particularly, the assay could detect exosomes in plasma and has potential to distinguish lung cancer patients from healthy volunteers with an area under the receiver operator characteristic curve of 0.85. Besides, the study provided an efficient method for analyzing the various divisions of exosomes by merely modifying the aptamer, which holds great promise for point-of-care applications.

Circulating Cancer-Associated Macrophage-like Cells as a Blood-Based Biomarker of Response to Immune Checkpoint Inhibitors

Evidence has been provided that circulating cancer-associated macrophage-like cell (CAM-L) numbers increase in response to chemotherapy, with an inverse trend compared to circulating tumor cells (CTCs). In the era of evolving cancer immunotherapy, whether CAM-Ls might have a potential role as predictive biomarkers of response has been unexplored. We evaluated whether a serial blood evaluation of CTC to CAM-L ratio might predict response to immune checkpoint inhibitors in a cohort of non-small-cell lung cancer patients. At baseline, CTCs, CAM-Ls, and the CTC/CAM-L ratio significantly correlate with both progression-free survival (PFS) and overall survival (OS). The baseline CTC/CAM-L ratio was significantly different in early progressors (4.28 ± 3.21) compared to long responders (0.42 ± 0.47) (p = 0.001). In patients treated with immune checkpoint inhibitors, a CTC/CAM-L ratio ≤ 0.25 at baseline is associated with better PFS and OS. A baseline CTC/CAM-L ratio ≤ 0.25 is statistically significant to discriminate early progressions from durable response. The results of the present pilot study suggest that CAM-Ls together with CTCs could play an important role in evaluating patients treated with cancer immunotherapy.

Unveiling the immune symphony: decoding colorectal cancer metastasis through immune interactions

Colorectal cancer (CRC), known for its high metastatic potential, remains a leading cause of cancer-related death. This review emphasizes the critical role of immune responses in CRC metastasis, focusing on the interaction between immune cells and tumor microenvironment. We explore how immune cells, through cytokines, chemokines, and growth factors, contribute to the CRC metastasis cascade, underlining the tumor microenvironment's role in shaping immune responses. The review addresses CRC's immune evasion tactics, especially the upregulation of checkpoint inhibitors like PD-1 and CTLA-4, highlighting their potential as therapeutic targets. We also examine advanced immunotherapies, including checkpoint inhibitors and immune cell transplantation, to modify immune responses and enhance treatment outcomes in CRC metastasis. Overall, our analysis offers insights into the interplay between immune molecules and the tumor environment, crucial for developing new treatments to control CRC metastasis and improve patient prognosis, with a specific focus on overcoming immune evasion, a key aspect of this special issue.