Diet restriction enhances the effect of immune checkpoint block by inhibiting the intratumoral mTORC1/B7-H3 axis.

Immune checkpoint blockade therapy has demonstrated significant therapeutic efficacy in certain cancer types; however, the impact of dietary restriction remains scarcely reported in this context. This study aimed to investigate the influence of dietary restriction on anti-PDL-1 therapy and the interplay of immune cells within this context. Using an anti-PDL-1 regimen combined with dietary restrictions, tumor progression was assessed in LLC-bearing mice. Flow cytometry was employed to analyze immune cell infiltration and differentiation levels within the tumor microenvironment. The expression of mTORC1/B7-H3 in tumors subjected to dietary restriction was also examined. LLC tumors with elevated B7-H3 expression were validated in mice to determine its inhibitory effect on immune cell proliferation and differentiation. A CD3/B7-H3 chimeric antibody was developed for therapeutic intervention in B7-H3 overexpressing tumors, with subsequent T cell responses assessed through flow cytometry. Dietary restriction potentiated the effect of anti-PDL1 therapy by suppressing the intratumorally mTORC1/B7-H3 axis. In vivo experiments demonstrated that elevated B7-H3 expression in tumors reduced infiltration and activation of CD8 + T cells within the tumor, while it did not affect tumor-infiltrating Tregs. In vitro studies revealed that high B7-H3 expression influenced the proliferation and activation of CD8 + T cells within a Coculture system. The constructed CD3/B7-H3 chimeric antibody prominently activated TCR within B7-H3 overexpressing tumors and impeded tumor progression. The findings suggest that dietary restriction enhances the efficacy of immune checkpoint blockade by modulating the intratumoral mTORC1/B7-H3 axis.

Physical activity enhances the effect of immune checkpoint blockade by inhibiting the intratumoral HIF1-α/CEACM1 axis.

Immune checkpoint blockade therapy has demonstrated significant therapeutic effects in certain types of cancers. However, there is limited reporting on the influence of physical activity on its efficacy. This study aimed to investigate the impact of physical activity on anti-PDL-1-mediated immune checkpoint therapy and the interplay of immune cells therein. HePa1-6 tumor-bearing mice were treated with anti-PDL-1 in conjunction with physical activity to assess tumor progression. Flow cytometry was utilized to analyze immune cell infiltration and differentiation levels within the tumor. The expression of HIF-a/CEACAM1 within the tumor due to physical activity was evaluated. HePa1-6 cells with high CEACAM1 expression were validated in mice to determine their inhibitory effects on immune cell proliferation and differentiation. A CD3/CEACAM1 chimeric antibody was developed for treating CEACAM1-overexpressing tumors, and flow cytometry was employed to assess T-cell response. Physical activity enhanced the efficacy of anti-PDL1 by suppressing the HIF-a/CEACAM1 axis within the tumor. In vivo experiments revealed that tumors with high CEACAM1 expression decreased infiltration and activation of CD8 + T cells within the tumor, suppressing T cell cytotoxicity without affecting Treg infiltration. In vitro, high CEACAM1 expression impacted the proliferation and activation of CD8 + T cells in a co-culture system. The constructed CD3/CEACAM1 chimeric antibody significantly activated the TCR within CEACAM1-overexpressing tumors and inhibited tumor progression. The findings suggest that physical activity augments the effectiveness of immune checkpoint blockade by inhibiting the intratumoral HIF1-α/CEACM1 axis.

Liposome-based nanomedicine for immune checkpoint blocking therapy and combinatory cancer therapy.

The discovery of immune checkpoint (IC) has led to a wave of leap forward in cancer immunotherapy that represents probably the most promising strategy for cancer therapy. However, the clinical use of immune checkpoint block (ICB) therapy is limited by response rates and side effects. A strategy that addresses the limitations of ICB therapies through combination therapies, using nanocarriers as mediators, has been mentioned in numerous research papers. Liposomes have been probably one of the most extensively used nanocarriers for clinical applications, with broad drug delivery and high safety. A timely review on this hot subject of research, i.e., the application of liposomes for ICB, is thus highly desirable for both fundamental and clinical translatable studies, but remains, to our knowledge, unexplored so far. For this purpose, this review is composed to address the dilemma of ICB therapy and the reasons for this dilemma. We later describe how other cancer treatments have broken this dilemma. Finally, we focus on the role of liposomes in various combinatory cancer therapy. This review is believed to serve as a guidance for the rational design and development of liposome for immunotherapy with enhanced therapeutic efficiency.

Linear Peptide-Based PET Tracers for Imaging PD-L1 in Tumors.

Programmed cell death receptor 1 (PD-1) and its ligand PD-L1 are particularly interesting immune checkpoint proteins for human cancer treatment. Positron emission tomography (PET) imaging allows for the dynamic monitoring of PD-L1 status during tumor progression, thus informing patients' response index. Herein, we report the synthesis of two linear peptide-based radiotracers, [64Cu]/[68Ga]HKP2201 and [64Cu]/[68Ga]HKP2202, and validate their utility for PD-L1 visualization in preclinical models. The precursor peptide HKP2201 was derived from a linear peptide ligand, CLP002, which was previously identified by phage display and showed nanomolar affinity toward PD-L1. Appropriate modification of CLP002 via PEGylation and DOTA conjugation yielded HKP2201. The dimerization of HKP2201 generated HKP2202. The 64Cu and 68Ga radiolabeling of both precursors was studied and optimized. PD-L1 expression in mouse melanoma cell line B16F10, mouse colon cancer cell line MC38, and their allografts were assayed by immunofluorescence and immunohistochemistry staining. Cellular uptake and binding assays were conducted in both cell lines. PET imaging and ex vivo biodistribution studies were employed in tumor mouse models bearing B16F10 and MC38 allografts. [64Cu]/[68Ga]HKP2201 and [64Cu]/[68Ga]HKP2202 were obtained with satisfactory radiocharacteristics. They all showed lower liver accumulation compared to [64Cu]/[68Ga]WL12. B16F10 and MC38 cells and their tumor allografts sections were verified to express PD-L1. These tracers demonstrated a concentration-dependent cell affinity and a comparable half-maximal effect concentration (EC50) with radiolabeled WL12. Competitive binding and blocking studies demonstrated the specific target of these tracers to PD-L1. PET imaging and ex vivo biodistribution studies revealed notable tumor uptake in tumor-bearing mice and rapid clearance from blood and major organs. Importantly, [64Cu]/[68Ga]HKP2202 showed higher tumor uptake compared to [64Cu]/[68Ga]HKP2201. Of note, [64Cu] labeled tracers showed longer retention in tumors than [68Ga] labeled traces, indicating advantages in the long-term tracking of PD-L1 dynamics. In comparison, [68Ga]HKP2201 and [68Ga]HKP2202 showed lower liver accumulation, enabling its great potential in the fast detection of both primary and metastatic tumors, including hepatic carcinoma. [64Cu]/[68Ga]HKP2201 and [64Cu]/[68Ga]HKP2202 are promising PET tracers for visualizing PD-L1 status. Notably, their combination would cooperate in rapid diagnosis and subsequent treatment guidance. Future assessment of the radiotracers in patients is needed to fully evaluate their clinical value.

Current situation of programmed cell death protein 1/programmed cell death ligand 1 inhibitors in advanced triple-negative breast cancer.

Triple-negative breast cancer (TNBC) has the worst prognosis among all molecular types of breast cancer. Because of the strong immunogenicity of TNBC cells, programmed death 1/programmed death ligand 1 (PD-1/PD-L1) inhibitors, two kinds of immune checkpoint blockade agents, might help improve the prognosis of TNBC. However, how to better use PD-1/PD-L1 inhibitors and select patients who may benefit from treatment options remains controversial. This article summarizes published clinical studies in which PD-1/PD-L1 inhibitors were used in patients with advanced TNBC to explore how to maximize effectiveness of these medications.

Enhancer RNA-based modeling of adverse events and objective responses of cancer immunotherapy reveals associated key enhancers and target genes.

Immune checkpoint inhibitors (ICI) targeting PD-1/PD-L1 or CTLA-4 are emerging and effective immunotherapy strategies. However, ICI-treated patients present heterogeneous responses and adverse events, thus demanding effective ways to assess benefit over risk before treatment. Here, by integrating pan-cancer clinical and molecular data, we tried to predict immune-related adverse events (irAEs, risk) and objective response rates (ORRs, benefit) based on enhancer RNAs (eRNAs) expression among patients receiving anti-PD-1/PD-L1 therapies. We built two tri-variate (eRNAs) regression models, one (with ENSR00000326714, ENSR00000148786, and ENSR00000005553) explaining 71% variance (R=0.84) of irAEs and the other (with ENSR00000164478, ENSR00000035913, and ENSR00000167231) explaining 79% (R=0.89) of ORRs. Interestingly, target genes of irAE-related enhancers, including upstream regulators of MYC, were involved in metabolism, inflammation, and immune activation, while ORR-related enhancers target PAK2 and DLG1 which participate in T cell activation. More importantly, we found that ENSR00000148786 probably enhanced TMEM43/LUMA expression mainly in B cells to induce irAEs in ICI-treated patients. Our study provides references for the identification of immunotherapy-related biomarkers and potential therapeutic targets during immunotherapy.

Combination of CD47-based nanoparticles and αPD-L1 for antitumor immunotherapy / 国际生物医学工程杂志

Objective:To investigate the therapeutic efficacy of the combination therapy with CD47-based nanoparticles and anti-PD-L1 monoclonal antibody (αPD-L1) for preventing tumor recurrence and metastasis in vivo.Methods:BALB/c mice were used to construct 4T1 tumor-bearing mouse models. The mouse model was treated with the combination therapy to analyze the effects on local tumor recurrence, tumor growth volume, survival time and lung metastasis in the 4T1 mammary tumor-bearing mouse model.Results:The combination therapy could effectively inhibit local tumor recurrence and prolong the survival time of tumor-bearing mice ( P<0.001). Compared with the αPD-L1 group, the combination therapy can increase the expression of cytokines tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in mouse serum (all P<0.05) and effector memory T cells in mouse spleen ( P<0.001). In addition, the results on the 4T1-Luc mammary tumor-bearing mouse lung metastasis model showed that the combination therapy could effectively inhibit tumor lung metastasis. Conclusions:The results strongly suggested that combination therapy with CD47-based nanoparticles and αPD-L1 can effectively elicit the memory immune response, and prevent tumor recurrence and lung metastasis.

KLHL22 maintains PD-1 homeostasis and prevents excessive T cell suppression.

Aberrant programmed cell death protein 1 (PD-1) expression on the surface of T cells is known to inhibit T cell effector activity and to play a pivotal role in tumor immune escape; thus, maintaining an appropriate level of PD-1 expression is of great significance. We identified KLHL22, an adaptor of the Cul3-based E3 ligase, as a major PD-1-associated protein that mediates the degradation of PD-1 before its transport to the cell surface. KLHL22 deficiency leads to overaccumulation of PD-1, which represses the antitumor response of T cells and promotes tumor progression. Importantly, KLHL22 was markedly decreased in tumor-infiltrating T cells from colorectal cancer patients. Meanwhile, treatment with 5-fluorouracil (5-FU) could increase PD-1 expression by inhibiting the transcription of KLHL22. These findings reveal that KLHL22 plays a crucial role in preventing excessive T cell suppression by maintaining PD-1 expression homeostasis and suggest the therapeutic potential of 5-FU in combination with anti-PD-1 in colorectal cancer patients.