Musashi-2 potentiates colorectal cancer immune infiltration by regulating the post-translational modifications of HMGB1 to promote DCs maturation and migration

The regulatory roles of RNA-binding proteins in the tumour immune microenvironment of gastrointestinal malignancies

The crosstalk between the tumour immune microenvironment (TIME) and tumour cells promote immune evasion and resistance to immunotherapy in gastrointestinal (GI) tumours. Post-transcriptional regulation of genes is pivotal to GI tumours progression, and RNA-binding proteins (RBPs) serve as key regulators via their RNA-binding domains. RBPs may exhibit either anti-tumour or pro-tumour functions by influencing the TIME through the modulation of mRNAs and non-coding RNAs expression, as well as post-transcriptional modifications, primarily N6-methyladenosine (m6A). Aberrant regulation of RBPs, such as HuR and YBX1, typically enhances tumour immune escape and impacts prognosis of GI tumour patients. Further, while targeting RBPs offers a promising strategy for improving immunotherapy in GI cancers, the mechanisms by which RBPs regulate the TIME in these tumours remain poorly understood, and the therapeutic application is still in its early stages. This review summarizes current advances in exploring the roles of RBPs in regulating genes expression and their effect on the TIME of GI tumours, then providing theoretical insights for RBP-targeted cancer therapies.

Enhancing immunogenicity and release of in situ-generated tumor vesicles for autologous vaccines

In situ vaccination (ISV) strategies offer an innovative approach to cancer immunotherapy by utilizing drug combinations directly at tumor sites to elicit personalized immune responses. Tumor cell-derived extracellular vesicles (TEVs) in ISV have great potential but face challenges such as low release rates and immunosuppressive proteins like programmed death ligand 1 (PD-L1) and CD47. This study develops a nanoparticle-based ISV strategy (Combo-NPs@shGNE) that enhances TEV release and modulates cargo composition. This approach combines Andrographolide, Icariside II, and shRNA targeting UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), which accumulates in the tumor region, resulting in the regulation of immunosuppressive pathways and the reduction of sialic acid production. Decreasing the level of sialylation on the membrane through necroptosis and inhibition of sialic acid synthesis decreased the loading of PD-L1 and CD47 on vesicles, while increasing the loading of heat shock protein 70 and high mobility group box 1 on vesicles, and induced the release of highly immunogenic TEVs from the cancer cells, with a 56.44 % release, 9.57 times higher than that of blank nanoparticle-treated cells. In vivo studies demonstrate that Combo-NPs@shGNE enhances TEV yield, tumor growth, reduces metastases, and improves survival in an osteosarcoma mouse model. It promotes dendritic cell maturation, increases CD4+ and CD8+ T cell infiltration, and alters the microenvironment by reducing myeloid-derived suppressor cells and enhancing immunostimulatory factors. Additionally, it transitions tumor-associated macrophages from M2 to an M1 phenotype, thereby augmenting tumor immunity. Overall, Combo-NPs@shGNE offers a promising method for transforming tumors into personalized autologous vaccines, potentially advancing cancer treatment strategies.

Reactive Oxygen Species-Responsive Pyroptosis Nanoinitiators Promote Immune Cell Infiltration and Activate Anti-Tumor Immune Response

Background

Immunotherapy, particularly immune checkpoint inhibitors, has become the standard treatment strategy for diverse malignant tumors. However, the inadequate infiltration of immune cells in tumors coupled with the immunosuppressive tumor microenvironment severely hinders the efficacy of immunotherapy.

Methods

A poly(ethylene glycol)-block-poly(lysine) copolymer (mPEG-b-PLL) was prepared through ring-opening polymerization and deprotection, and thioketal (TK) was attached to the amino group of mPEG-b-PLL via the condensation reaction to obtain mPEG-b-PLL-TK. Doxorubicin (DOX) and decitabine (DAC) were encapsulated in mPEG-b-PLL-TK to prepare the pyroptosis nanoinitiator (NP/(DAC+DOX)). The drug release behavior, cellular uptake, pyroptosis-triggering performance, and cytotoxicity of NP/(DAC+DOX) were evaluated in vitro experiments. The in vivo pharmacokinetics and biodistribution of NP/(DAC+DOX) were assessed through fluorescence imaging and high-performance liquid chromatography analysis. CT26 and 4T1 tumor-bearing mouse models were established to evaluate the anti-tumor efficacy, pyroptosis-triggering performance, and immune activation effects of NP/(DAC+DOX).

Results

NP/(DAC+DOX) exhibited excellent reactive oxygen species (ROS)-responsive drug release behavior and could be effectively taken up by tumor cells. Experiments both in vitro and in vivo demonstrated that NP/(DAC+DOX) effectively triggered pyroptosis in tumor cells, which was attributed to the DOX-induced activation of caspase-3 and the upregulation of GSDME expression caused by DAC. Following intravenous administration, NP/(DAC+DOX) specifically aggregated in tumor tissues. NP/(DAC+DOX) significantly suppressed tumor growth and extended the survival time of tumor-bearing mice. Furthermore, NP/(DAC+DOX) promoted dendritic cell maturation, enhanced the infiltration of cytotoxic T lymphocytes within the tumor, and decreased the proportion of myeloid-derived suppressor cells.

Conclusion

This study developed a ROS-responsive pyroptosis nanoinitiator to precisely induce the pyroptosis of tumor cells, thereby enhancing intratumoral immune cell infiltration and activating anti-tumor immune responses.

Single-cell sequencing technology to characterize stem T-cell subpopulations in acute T-lymphoblastic leukemia and the role of stem T-cells in the disease process

BACKGROUND

Precursor T-cell acute lymphoblastic leukemia (Pre-T ALL) is a malignant neoplastic disease in which T-cells proliferate in the bone marrow. Single-cell sequencing technology could identify characteristic cell types, facilitating the study of the therapeutic mechanisms in Pre-T ALL.

METHODS

The single-cell sequencing data (scRNA-seq) of Pre-T ALL were obtained from public databases. Key immune cell subpopulations involved in the progression of Pre-T ALL were identified by clustering and annotating the cellular data using AUCell. Next, pseudo-temporal analysis was performed to identify the differentiation trajectories of immune cell subpopulations using Monocle. Copy number mutation landscape of cell subpopulations was characterized by inferCNV. Finally, cellphoneDB was used to analyze intercellular communication relationships.

RESULTS

A total of 10 cellular subpopulations were classified, with Pre-T ALL showing a higher proportion of NK/T cells. NK/T cells were further clustered into two subpopulations. Stem T cells showed a high expression of marker genes related to hematopoietic stem cells, Naive T cells had a high expression of CCR7, CCR7, RCAN3, and NK cells high-expressed KLRD1, TRDC. The cell proliferation was reduced and the activation of T cell was increased during the differentiation of stem T cells to Naive T cells. We observed interaction between stem T cells with dendritic cells such as CD74-COPA, CD74-MIF as well as co-inhibition-related interactions such as LGALS9-HAVCR2, TGFB1-TGFBR3.

CONCLUSION

Stem T cells were involved in the development of Pre-T-ALL through the regulatory effects of transcription factors (TFs) KLF2 and FOS and multiple ligand-receptor pairs.

Deciphering the roles of the HMGB family in cancer: Insights from subcellular localization dynamics

The high-mobility group box (HMGB) family consists of four DNA-binding proteins that regulate chromatin structure and function. In addition to their intracellular functions, recent studies have revealed their involvement as extracellular damage-associated molecular patterns (DAMPs), contributing to immune responses and tumor development. The HMGB family promotes tumorigenesis by modulating multiple processes including proliferation, metabolic reprogramming, metastasis, immune evasion, and drug resistance. Due to the predominant focus on HMGB1 in the literature, little is known about the remaining members of this family. This review summarizes the structural, distributional, as well as functional similarities and distinctions among members of the HMGB family, followed by a comprehensive exploration of their roles in tumor development. We emphasize the distributional and functional hierarchy of the HMGB family at both the organizational and subcellular levels, with a focus on their relationship with the tumor immune microenvironment (TIME), aiming to prospect potential strategies for anticancer therapy.

Targeting the "tumor microenvironment": RNA-binding proteins in the spotlight in colorectal cancer therapy

Colorectal cancer (CRC) is the third most common cancer and has the second highest mortality rate among cancers. The development of CRC involves both genetic and epigenetic abnormalities, and recent research has focused on exploring the ex-transcriptome, particularly post-transcriptional modifications. RNA-binding proteins (RBPs) are emerging epigenetic regulators that play crucial roles in post-transcriptional events. Dysregulation of RBPs can result in aberrant expression of downstream target genes, thereby affecting the progression of colorectal tumors and the prognosis of patients. Recent studies have shown that RBPs can influence CRC pathogenesis and progression by regulating various components of the tumor microenvironment (TME). Although previous research on RBPs has primarily focused on their direct regulation of colorectal tumor development, their involvement in the remodeling of the TME has not been systematically reported. This review aims to highlight the significant role of RBPs in the intricate interactions within the CRC tumor microenvironment, including tumor immune microenvironment, inflammatory microenvironment, extracellular matrix, tumor vasculature, and CRC cancer stem cells. We also highlight several compounds under investigation for RBP-TME-based treatment of CRC, including small molecule inhibitors such as antisense oligonucleotides (ASOs), siRNAs, agonists, gene manipulation, and tumor vaccines. The insights gained from this review may lead to the development of RBP-based targeted novel therapeutic strategies aimed at modulating the TME, potentially inhibiting the progression and metastasis of CRC.