Colorectal cancer: Metabolic interactions reshape the tumor microenvironment

DHRS2-induced SPHK1 downregulation contributes to the cell growth inhibition by Trichothecin in colorectal carcinoma

BACKGROUND

Deregulation of lipid metabolism is one of the most prominent metabolic features in cancer. The activation of sphingolipid metabolic pathways affects the proliferation, invasion, angiogenesis, chemoresistance, and immune escape of tumors, including colorectal cancer (CRC). Dehydrogenase/reductase member 2 (DHRS2), which belongs to the short-chain dehydrogenase/reductase (SDR) family, has been reported to participate in the regulation of lipid metabolism and impact on cancer progression. Trichothecin (TCN) is a sesquiterpenoid metabolite originating from an endophytic fungus of the herbal plant Maytenus hookeri Loes. Studies have shown that TCN exerts a broad-spectrum antitumor activity.

METHODS

We evaluated the proliferative ability of CRC cells by CCK8 and colony formation assays. A metabolite profiling using liquid chromatography coupled with mass spectrometry (LC/MS) was adopted to identify the proximal metabolite changes linked to DHRS2 overexpression. RNA stability assay and RNA immunoprecipitation (RIP) experiments were applied to determine the post-transcriptional regulation of SPHK1 expression by DHRS2. We used flow cytometry to detect changes in cell cycle and cell apoptosis of CRC cells in the absence or presence of TCN.

RESULTS

We demonstrate that DHRS2 hampers the sphingosine kinases 1 (SPHK1)/sphingosine 1-phosphate (S1P) metabolic pathway to inhibit CRC cell growth. DHRS2 directly binds to SPHK1 mRNA to accelerate its degradation in a post-transcriptionally regulatory manner. Moreover, we illustrate that SPHK1 downregulation induced by DHRS2 contributes to TCN-induced growth inhibition of CRC.

CONCLUSIONS

The present study provides a mechanistic connection among metabolic enzymes, metabolites, and the malignant progression of CRC. Moreover, TCN could be developed as a potential pharmacological tool against CRC by the induction of DHRS2 and targeting SPHK1/S1P metabolic pathway.

Impact and potential value of immunosenescence on solid gastrointestinal tumors

Solid gastrointestinal tumors often respond poorly to immunotherapy for the complex tumor microenvironment (TME), which is exacerbated by immune system alterations. Immunosenescence is the process of increased diversification of immune genes due to aging and other factors, leading to a decrease in the recognition function of the immune system. This process involves immune organs, immune cells, and the senescence-associated secretory phenotype (SASP). The most fundamental change is DNA damage, resulting in TME remodeling. The main manifestations are worsening inflammation, increased immunosuppressive SASP production, decreased immune cell antitumor activity, and the accumulation of tumor-associated fibroblasts and myeloid-derived suppressor cells, making antitumor therapy less effective. Senotherapy strategies to remove senescent cells and block key senescence processes can have synergistic effects with other treatments. This review focuses on immunoenescence and its impact on the solid TME. We characterize the immunosenescent TME and discuss future directions for antitumor therapies targeting senescence.

Nano-energy interference: A novel strategy for blunting tumor adaptation and metastasis

Blunting the tumor's stress-sensing ability is an effective strategy for controlling tumor adaptive survival and metastasis. Here, we have designed a cyclically amplified nano-energy interference device based on lipid nanoparticles (LNP), focused on altering cellular energy metabolism. This innovative nano device efficiently targets and monitors the tumor's status while simultaneously inhibiting mitochondrial respiration, biogenesis and ribosome production. To this end, we first identified azelaic acid (AA), a binary acid capable of disrupting the mitochondrial respiratory chain. Upon encapsulation in LNP and linkage to mitochondrial-targeting molecules, this disruptive effect is further augmented. Consequently, tumors exhibit a substantial upregulation of the glycolytic pathway, intensifying their glucose demand and worsening the tumor's energy-deprived microenvironment. Then, the glucose analog, 2-Deoxy-D-glucose (2-DG), linked to the LNP, efficiently targets tumors and competitively inhibits the tumor's normal glucose uptake. The synergetic results of combining AA with 2-DG induce comprehensive energy deficiency within tumors, blocking the generation of energy-sensitive ribosomes. Ultimately, the disruption of both mitochondria and ribosomes depletes energy supply and new protein-generating capacity, weakening tumor's ability to adapt to environmental stress and thereby inhibiting growth and metastasis. Comprehensively, this nano-energy interference device, by controlling the tumor's stress-sensing ability, provides a novel therapeutic strategy for refractory tumors.

In Silico Analysis of Selective Bioactive Compounds from Acronychia Pedunculata as a Potential Inhibitor of HER2 in Colorectal Cancer

Colorectal cancer (CRC) is a pervasive malignancy that stands as a prominent contributor to global cancer-related mortality. Among the numerous causative factors, the overexpression of human epidermal growth factor receptor 2 (HER2) is notably linked to CRC progression. Acronychia (A.) pedunculata has a longstanding history in folk medicine due to its multifaceted medicinal attributes. This study aimed to assess the potential of specific bioactive compounds derived from A. pedunculata for their inhibition of HER2 in CRC, utilizing in silico analysis. The compounds were systematically evaluated through a series of computational analyses. Drug-likeness assessment, pharmacokinetic evaluation, and toxicity analysis were conducted. Molecular docking studies were performed to investigate binding affinities with the HER2 target. Additionally, bioavailability radar analysis was employed to predict oral bioavailability, while molecular target prediction provided insights into potential protein interactions. All 12 compounds demonstrated favorable drug-likeness properties and adherence to Lipinski's rule of five, indicative of the potential for good oral bioavailability. Four compounds were found to have no toxicological endpoints. Molecular docking revealed two compounds, namely caryophylla-4 (14), 8 (15)-dien-5alpha-ol and (-)-globulol, which showed promising binding affinities between several compounds and HER2. From this study, two leads were identified from A. pedunculata. Further experimental studies are required to validate the action of leads.

Metabolic heterogeneity in clear cell renal cell carcinoma revealed by single-cell RNA sequencing and spatial transcriptomics

BACKGROUND

Clear cell renal cell carcinoma is a prototypical tumor characterized by metabolic reprogramming, which extends beyond tumor cells to encompass diverse cell types within the tumor microenvironment. Nonetheless, current research on metabolic reprogramming in renal cell carcinoma mostly focuses on either tumor cells alone or conducts analyses of all cells within the tumor microenvironment as a mixture, thereby failing to precisely identify metabolic changes in different cell types within the tumor microenvironment.

METHODS

Gathering 9 major single-cell RNA sequencing databases of clear cell renal cell carcinoma, encompassing 195 samples. Spatial transcriptomics data were selected to conduct metabolic activity analysis with spatial localization. Developing scMet program to convert RNA-seq data into scRNA-seq data for downstream analysis.

RESULTS

Diverse cellular entities within the tumor microenvironment exhibit distinct infiltration preferences across varying histological grades and tissue origins. Higher-grade tumors manifest pronounced immunosuppressive traits. The identification of tumor cells in the RNA splicing state reveals an association between the enrichment of this particular cellular population and an unfavorable prognostic outcome. The energy metabolism of CD8+ T cells is pivotal not only for their cytotoxic effector functions but also as a marker of impending cellular exhaustion. Sphingolipid metabolism evinces a correlation with diverse macrophage-specific traits, particularly M2 polarization. The tumor epicenter is characterized by heightened metabolic activity, prominently marked by elevated tricarboxylic acid cycle and glycolysis while the pericapsular milieu showcases a conspicuous enrichment of attributes associated with vasculogenesis, inflammatory responses, and epithelial-mesenchymal transition. The scMet facilitates the transformation of RNA sequencing datasets sourced from TCGA into scRNA sequencing data, maintaining a substantial degree of correlation.

CONCLUSIONS

The tumor microenvironment of clear cell renal cell carcinoma demonstrates significant metabolic heterogeneity across various cell types and spatial dimensions. scMet exhibits a notable capability to transform RNA sequencing data into scRNA sequencing data with a high degree of correlation.

Increased circulating regulatory T cells and decreased follicular T helper cells are associated with colorectal carcinogenesis

Objective

Colorectal cancer (CRC) is the third most prevalent cancer worldwide and is associated with high morbidity and mortality rates. Colorectal carcinogenesis occurs via the conventional adenoma-to-carcinoma and serrated pathways. Conventional T helper (Th) and innate lymphoid cells (ILCs) play vital roles in maintaining intestinal homeostasis. However, the contribution of these two major lymphoid cell populations and their associated cytokines to CRC development is unclear. Therefore, we aimed to analyze peripheral lymphocyte profiles during colorectal carcinogenesis.

Methods

We collected 86 blood samples concurrently, and pathologists confirmed the presence of various pathological conditions (i.e., HPs, adenoma, and carcinoma) using hematoxylin and eosin staining. Ten healthy donors were recruited as healthy controls (HCs) from the physical examination center. We performed flow cytometry on peripheral blood mononuclear cells collected from patients with various pathological conditions and the HCs, and cytokines (interleukin-2, interleukin-4, interleukin-5, interleukin-13, interleukin-17A, interleukin-17F, interleukin-22, interferon-γ, and tumor necrosis factor-α) were quantified. We also analyzed the published single-cell RNA sequence data derived from tissue samples from different stages of colorectal carcinogenesis.

Results

The cytokine response in peripheral CD4+ T cells was upregulated during the carcinoma process. The frequency of peripheral regulatory T cells (Tregs) increased in the adenoma and carcinoma stages. While the T follicular helper (Tfh) cell proportion was downregulated in the adenoma and carcinoma processes. Thus, Th cell subsets, especially Tregs and Tfh cells, were involved in colonic diseases. Moreover, the immunological profile characteristics in the HPs were clarified.

Conclusion

We comprehensively analyzed circulating ILCs and adaptive T-cell lymphocyte subtypes in colorectal carcinoma progression. Our results show the immunological profile characteristics and support the involvement of Th subsets, especially Treg and Tfh cell populations, in colonic diseases. These findings significantly enhance our understanding of the immune mechanisms underlying CRC and its precancerous lesions. Further investigation of the Treg and Tfh cells' function in colorectal disease development will provide potential therapeutic targets for monitoring and preventing CRC development.

Arabinose confers protection against intestinal injury by improving integrity of intestinal mucosal barrier

There is a growing amount of research that highlights the significant involvement of metabolic imbalance and the inflammatory response in the advancement of colitis. Arabinose is a naturally occurring bioactive monosaccharide that plays a crucial role in the metabolic processes and synthesis of many compounds in living organisms. However, the more detailed molecular mechanism by which the administration of arabinose alleviates the progression of colitis and its associated carcinogenesis is still not fully understood. In the present study, arabinose is recognized as a significant and inherent protector of the intestinal mucosal barrier through its role in preserving the integrity of tight junctions within the intestines. Also, it is important to note that there is a positive correlation between the severity of inflammatory bowel disease (IBD) and colorectal cancer (CRC), as well as chemically-induced colitis in mice, and lower levels of arabinose in the bloodstream. In two mouse models of colitis, caused by dextran sodium sulfate (DSS) or by spontaneous colitis in IL-10-/- mice, damage to the intestinal mucosa was reduced by giving the mice arabinose. When arabinose is administrated to model with colitis, it sets off a chain of events that help keep the lysosomes together and stop cathepsin B from being released. During the progression of intestinal epithelial injury, this process blocks myosin light chain kinase (MLCK) from damaging tight junctions and causing mitochondrial dysfunction. In summary, the results of the study have provided evidence supporting the beneficial effects of arabinose in mitigating the progression of colitis. This is achieved through its ability to avoid dysregulation of the intestinal barrier. Consequently, arabinose may hold promise as a therapeutic supplementation for the management of colitis.

Targeting dysregulated lipid metabolism in the tumor microenvironment

The reprogramming of lipid metabolism and its association with oncogenic signaling pathways within the tumor microenvironment (TME) have emerged as significant hallmarks of cancer. Lipid metabolism is defined as a complex set of molecular processes including lipid uptake, synthesis, transport, and degradation. The dysregulation of lipid metabolism is affected by enzymes and signaling molecules directly or indirectly involved in the lipid metabolic process. Regulation of lipid metabolizing enzymes has been shown to modulate cancer development and to avoid resistance to anticancer drugs in tumors and the TME. Because of this, understanding the metabolic reprogramming associated with oncogenic progression is important to develop strategies for cancer treatment. Recent advances provide insight into fundamental mechanisms and the connections between altered lipid metabolism and tumorigenesis. In this review, we explore alterations to lipid metabolism and the pivotal factors driving lipid metabolic reprogramming, which exacerbate cancer progression. We also shed light on the latest insights and current therapeutic approaches based on small molecular inhibitors and phytochemicals targeting lipid metabolism for cancer treatment. Further investigations are worthwhile to fully understand the underlying mechanisms and the correlation between altered lipid metabolism and carcinogenesis.

Functional enrichment analysis of LYSET and identification of related hub gene signatures as novel biomarkers to predict prognosis and immune infiltration status of clear cell renal cell carcinoma

PURPOSE

The latest research shows that the lysosomal enzyme trafficking factor (LYSET) encoded by TMEM251 is a key regulator of the amino acid metabolism reprogramming (AAMR) and related pathways significantly correlate with the progression of some tumors. The purpose of this study was to explore the potential pathways of the TMEM251 in clear cell renal cell carcinoma (ccRCC) and establish related predictive models based on the hub genes in these pathways for prognosis and tumor immune microenvironment (TIME).

METHODS

We obtained mRNA expression data and clinical information of ccRCC samples from The Cancer Genome Atlas (TCGA), E-MATE-1980, and immunotherapy cohorts. Single-cell sequencing data (GSE152938) were downloaded from the Gene Expression Omnibus (GEO) database. We explored biological pathways of the LYSET by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of TMEM251-coexpression genes. The correlation of LYSET-related pathways with the prognosis was conducted by Gene Set Variation Analysis (GSVA) and unsupervised cluster analysis. The least absolute shrinkage and selection operator (LASSO) and Cox regression were used to identify hub prognostic genes and construct the risk score. Immune infiltration analysis was conducted by CIBERSORTx and Tumor Immune Estimation Resource (TIMER) databases. The predictive value of the risk score and hub prognostic genes on immunotherapy responsiveness was analyzed through the tumor mutation burden (TMB) score, immune checkpoint expression, and survival analysis. Immunohistochemistry (IHC) was finally used to verify the expressions of hub prognostic genes.

RESULTS

The TMEM251 was found to be significantly correlated with some AAMR pathways. AAGAB, ENTR1, SCYL2, and WDR72 in LYSET-related pathways were finally identified to construct a risk score model. Immune infiltration analysis showed that LYSET-related gene signatures significantly influenced the infiltration of some vital immune cells such as CD4 + cells, NK cells, M2 macrophages, and so on. In addition, the constructed risk score was found to be positively correlated with TMB and some common immune checkpoint expressions. Different predictive values of these signatures for Nivolumab therapy responsiveness were also uncovered in immunotherapy cohorts. Finally, based on single-cell sequencing analysis, the TMEM251 and the hub gene signatures were found to be expressed in tumor cells and some immune cells. Interestingly, IHC verification showed a potential dual role of four hub genes in ccRCC progression.

CONCLUSION

The novel predictive biomarkers we built may benefit clinical decision-making for ccRCC. Our study may provide some evidence that LYSET-related gene signatures could be novel potential targets for treating ccRCC and improving immunotherapy efficacy. Our nomogram might be beneficial to clinical choices, but the results need more experimental verifications in the future.

The role of circadian clock genes in colorectal carcinoma: Novel insights into regulatory mechanism and implications in clinical therapy

Colorectal cancer (CRC) is a lethal malignancy with limited treatment strategies. Accumulating evidence indicates that CRC tumorigenesis, progression and metastasis are intimately associated with circadian clock, an inherent 24-h cycle oscillation of biochemical, physiological functions in almost every eukaryote. In the present review, we summarize the altered expression level of circadian genes in CRC and the prognosis associated with gene abundance switch. We illustrate the function and potential mechanisms of circadian genes in CRC pathogenesis and progression. Moreover, circadian based-therapeutic strategies including chronotherapy, therapeutics targeting potential circadian components, and melatonin treatment in CRC are also highlighted.

Expression of an oxysterol-metabolizing enzyme in colorectal cancer and its relation to tumor cell behavior and prognosis

Oxysterols and oxysterol-metabolizing enzymes have been implicated in the pathogenesis of various cancers. However, the distinct function of the oxysterol-metabolizing enzyme cytochrome P450 family 39 Subfamily A Member 1 (CYP39A1) in colorectal cancer (CRC) remains unclear. The aims of the current study were to evaluate whether CYP39A1 affects the oncogenic behaviors of CRC cells and to investigate the prognostic value of its expression in CRC. A CYP39A1 small-interfering RNA was used to block CYP39A1 gene expression in DLD1 and SW480 cells. The expression of CYP39A1 in CRC tissues was investigated by immunohistochemistry. Tumor angiogenesis and lymphangiogenesis were assessed by CD34 and D2-40 immunohistochemical staining, respectively. CYP39A1 knockdown inhibited tumor cell migration and invasion in DLD1 and SW480 cells. Angiogenesis was also inhibited through the decreased expression of vascular endothelial growth factor (VEGF)-A and hypoxia-inducible factor (HIF)-1α, and angiostatin and endostatin expression increased. In addition, CYP39A1 knockdown inhibited the lymphangiogenesis by decreasing the expression of VEGF-C. CYP39A1 expression was increased in CRC tissues compared with normal colorectal mucosa. CYP39A1 expression was associated with tumor stage, depth of invasion, lymph node metastasis, distant metastasis, and poor survival. The microvessel and lymphatic vessel density values of CYP39A1-positive tumors were significantly higher than those of CYP39A1-negative tumors. These results indicate that CYP39A1 is associated with tumor progression by influencing tumor cell angiogenesis and lymphangiogenesis in CRC.

Metabolic reprogramming in nasopharyngeal carcinoma: Mechanisms and therapeutic opportunities

The high prevalence of metabolic reprogramming in nasopharyngeal carcinoma (NPC) offers an abundance of potential therapeutic targets. This review delves into the distinct mechanisms underlying metabolic reprogramming in NPC, including enhanced glycolysis, nucleotide synthesis, and lipid metabolism. All of these changes are modulated by Epstein-Barr virus (EBV) infection, hypoxia, and tumor microenvironment. We highlight the role of metabolic reprogramming in the development of NPC resistance to standard therapies, which represents a challenging barrier in treating this malignancy. Furthermore, we dissect the state of the art in therapeutic strategies that target these metabolic changes, evaluating the successes and failures of clinical trials and the strategies to tackle resistance mechanisms. By providing a comprehensive overview of the current knowledge and future directions in this field, this review sets the stage for new therapeutic avenues in NPC.

Selenium metabolism heterogeneity in pan-cancer: insights from bulk and single-cell RNA sequencing

BACKGROUND

Selenium, a natural microelement with both nutritional and toxicological properties, is intertwined with tumorigenesis and progression. However, it is not fully understood how selenium metabolism affects immune response and cancer biology.

METHODS

We estimated selenium metabolism by Gene Set Enrichment Analysis (GSEA) to delineate the selenium metabolism landscape using The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), Cancer Cell Line Encyclopedia (CCLE) and a integrated pan-cancer single-cell dataset. We systematically explored the prognostic implications of selenium metabolism and selenium-related regulatory patterns. The therapeutic value of selenium metabolism was explored through machine learning and examined in several immunotherapy cohorts. The heterogeneity and underlying mechanism of selenium metabolism were investigated by cell‒cell communication analysis at the single-cell level.

RESULTS

A GSEA analysis based on 86 genes was used to evaluate the selenium metabolism landscape. The selenium metabolism score exhibited prognostic value in predicting the lower risk of mortality, possibly due to its correlation with multiple cancer hallmarks, including a positive correlation with complement (R = 0.761, P < 0.001), inflammatory response (R = 0.663, P < 0.001), apoptosis (R = 0.626, P < 0.001), hypoxia (R = 0.587, P < 0.001), reactive oxygen species (ROS) (R = 0.558, P < 0.001), and interferon gamma response (R = 0.539, P < 0.001). We also observed heterogeneity in the relationship between selenium metabolism and immunity across different cancers. Based on selenium-related genes, we constructed a machine learning model with area under the ROC curve (AUC) of 0.82 in predicting immune checkpoint inhibitor (ICI)-based immunotherapy response. Single-cell selenium metabolism quantification revealed that adjacent and tumor tissues had higher selenium metabolism compared with normal tissues, especially in epithelial cells, fibroblasts and macrophages. The communication between high-selenium epithelium and high-selenium fibroblast was significantly higher than other cells, especially in cytokines, chemokines, collagen, Wnt, VEGF, IGF and FGF pathways.

CONCLUSION

Our study provides a comprehensive landscape of selenium metabolism levels and diverse regulatory patterns in different cancers, deepening the understanding of selenium's roles in tumorigenesis and immunity.

Anoikis resistance and immune escape mediated by Epstein-Barr virus-encoded latent membrane protein 1-induced stabilization of PGC-1α promotes invasion and metastasis of nasopharyngeal carcinoma

BACKGROUND

Epstein-Barr virus (EBV) is the first discovered human tumor virus that is associated with a variety of malignancies of both lymphoid and epithelial origin including nasopharyngeal carcinoma (NPC). The EBV-encoded latent membrane protein 1 (LMP1) has been well-defined as a potent oncogenic protein, which is intimately correlated with NPC pathogenesis. Anoikis is considered to be a physiological barrier to metastasis, and avoiding anoikis is a major hallmark of metastasis. However, the role of LMP1 in anoikis-resistance and metastasis of NPC has not been fully identified.

METHODS

Trypan blue staining, colony formation assay, flow cytometry, and TUNEL staining, as well as the detection of apoptosis and anoikis resistance-related markers was applied to evaluate the anoikis-resistant capability of NPC cells cultured in ultra-low adhesion condition. Co-immunoprecipitation (Co-IP) experiment was performed to determine the interaction among LMP1, PRMT1 and PGC-1α. Ex vivo ubiquitination assay was used to detect the ubiquitination level of PGC-1α. Anoikis- resistant LMP1-positive NPC cell lines were established and applied for the xenograft and metastatic animal experiments.

RESULTS

Our current findings reveal the role of LMP1-stabilized peroxisome proliferator activated receptor coactivator-1a (PGC-1α) in anoikis resistance and immune escape to support the invasion and metastasis of NPC. Mechanistically, LMP1 enhances PGC-1α protein stability by promoting the interaction between arginine methyltransferase 1 (PRMT1) and PGC-1α to elevate the methylation modification of PGC-1α, thus endowing NPC cells with anoikis-resistance. Meanwhile, PGC-1α mediates the immune escape induced by LMP1 by coactivating with STAT3 to transcriptionally up-regulate PD-L1 expression.

CONCLUSION

Our work provides insights into how virus-encoded proteins recruit and interact with host regulatory elements to facilitate the malignant progression of NPC. Therefore, targeting PGC-1α or PRMT1-PGC-1α interaction might be exploited for therapeutic gain for EBV-associated malignancies.

Dual effects of radiotherapy on tumor microenvironment and its contribution towards the development of resistance to immunotherapy in gastrointestinal and thoracic cancers

Successful clinical methods for tumor elimination include a combination of surgical resection, radiotherapy, and chemotherapy. Radiotherapy is one of the crucial components of the cancer treatment regimens which allow to extend patient life expectancy. Current cutting-edge radiotherapy research is focused on the identification of methods that should increase cancer cell sensitivity to radiation and activate anti-cancer immunity mechanisms. Radiation treatment activates various cells of the tumor microenvironment (TME) and impacts tumor growth, angiogenesis, and anti-cancer immunity. Radiotherapy was shown to regulate signaling and anti-cancer functions of various TME immune and vasculature cell components, including tumor-associated macrophages, dendritic cells, endothelial cells, cancer-associated fibroblasts (CAFs), natural killers, and other T cell subsets. Dual effects of radiation, including metastasis-promoting effects and activation of oxidative stress, have been detected, suggesting that radiotherapy triggers heterogeneous targets. In this review, we critically discuss the activation of TME and angiogenesis during radiotherapy which is used to strengthen the effects of novel immunotherapy. Intracellular, genetic, and epigenetic mechanisms of signaling and clinical manipulations of immune responses and oxidative stress by radiotherapy are accented. Current findings indicate that radiotherapy should be considered as a supporting instrument for immunotherapy to limit the cancer-promoting effects of TME. To increase cancer-free survival rates, it is recommended to combine personalized radiation therapy methods with TME-targeting drugs, including immune checkpoint inhibitors.

Role of Epithelial to Mesenchymal Transition in Colorectal Cancer

The epithelial-mesenchymal transition (EMT) is a cellular reprogramming process that occurs during embryonic development and adult tissue homeostasis. This process involves epithelial cells acquiring a mesenchymal phenotype. Through EMT, cancer cells acquire properties associated with a more aggressive phenotype. EMT and its opposite, mesenchymal-epithelial transition (MET), have been described in more tumors over the past ten years, including colorectal cancer (CRC). When EMT is activated, the expression of the epithelial marker E-cadherin is decreased and the expression of the mesenchymal marker vimentin is raised. As a result, cells temporarily take on a mesenchymal phenotype, becoming motile and promoting the spread of tumor cells. Epithelial-mesenchymal plasticity (EMP) has become a hot issue in CRC because strong inducers of EMT (such as transforming growth factor β, TGF-β) can initiate EMT and regulate metastasis, microenvironment, and immune system resistance in CRC. In this review, we take into account the significance of EMT-MET in CRC and the impact of the epithelial cells' plasticity on the prognosis of CRC. The analysis of connection between EMT and colorectal cancer stem cells (CCSCs) will help to further clarify the current meager understandings of EMT. Recent advances affecting important EMT transcription factors and EMT and CCSCs are highlighted. We come to the conclusion that the regulatory network for EMT in CRC is complicated, with a great deal of crosstalk and alternate paths. More thorough research is required to more effectively connect the clinical management of CRC with biomarkers and targeted treatments associated with EMT.

The emerging role of exosomes in the development of testicular

The mechanisms of testicular development in mammals are complex. Testis is an organ that produces sperm and secretes androgens. It is rich in exosomes and cytokines that mediate signal transduction between tubule germ cells and distal cells, promoting testicular development and spermatogenesis. Exosomes are nanoscale extracellular vesicles that transmit information between cells. By transmitting information, exosomes play an important role in male infertility diseases such as azoospermia, varicocele, and testicular torsion. However, due to the wide range of sources of exosomes, extraction methods are numerous and complex. Therefore, there are many difficulties in studying the mechanisms of exosomal effects on normal development and male infertility. Therefore, in this review, first, we introduce the formation of exosomes and methods for culturing testis and sperm. Then, we introduce the effects of exosomes on different stages of testicular development. Finally, we summarize the prospects and shortcomings of exosomes when used in clinical applications. We lay the theoretical foundation for the mechanism of the influence of exosomes on normal development and male infertility.

The Prognostic and therapeutic value and clinical implications of fibroblast activation protein-α as a novel biomarker in colorectal cancer

The identification of contributing factors leading to the development of Colorectal Cancer (CRC), as the third fatal malignancy, is crucial. Today, the tumor microenvironment has been shown to play a key role in CRC progression. Fibroblast-Activation Protein-α (FAP) is a type II transmembrane cell surface proteinase expressed on the surface of cancer-associated fibroblasts in tumor stroma. As an enzyme, FAP has di- and endoprolylpeptidase, endoprotease, and gelatinase/collagenase activities in the Tumor Microenvironment (TME). According to recent reports, FAP overexpression in CRC contributes to adverse clinical outcomes such as increased lymph node metastasis, tumor recurrence, and angiogenesis, as well as decreased overall survival. In this review, studies about the expression level of FAP and its associations with CRC patients' prognosis are reviewed. High expression levels of FAP and its association with clinicopathological factors have made as a potential target. In many studies, FAP has been evaluated as a therapeutic target and diagnostic factor into which the current review tries to provide a comprehensive insight. Video Abstract.

Nanomaterials in tumor immunotherapy: new strategies and challenges

Tumor immunotherapy exerts its anti-tumor effects by stimulating and enhancing immune responses of the body. It has become another important modality of anti-tumor therapy with significant clinical efficacy and advantages compared to chemotherapy, radiotherapy and targeted therapy. Although various kinds of tumor immunotherapeutic drugs have emerged, the challenges faced in the delivery of these drugs, such as poor tumor permeability and low tumor cell uptake rate, had prevented their widespread application. Recently, nanomaterials had emerged as a means for treatment of different diseases due to their targeting properties, biocompatibility and functionalities. Moreover, nanomaterials possess various characteristics that overcome the defects of traditional tumor immunotherapy, such as large drug loading capacity, precise tumor targeting and easy modification, thus leading to their wide application in tumor immunotherapy. There are two main classes of novel nanoparticles mentioned in this review: organic (polymeric nanomaterials, liposomes and lipid nanoparticles) and inorganic (non-metallic nanomaterials and metallic nanomaterials). Besides, the fabrication method for nanoparticles, Nanoemulsions, was also introduced. In summary, this review article mainly discussed the research progress of tumor immunotherapy based on nanomaterials in the past few years and offers a theoretical basis for exploring novel tumor immunotherapy strategies in the future.

Novel IL4I1 Inhibitors for Treating Cancer

Provided herein are novel IL4I1 inhibitors, their pharmaceutical compositions, the use of such compounds in treating cancer, and processes for preparing such compounds.

Crosstalk between colorectal cancer cells and cancer-associated fibroblasts in the tumor microenvironment mediated by exosomal noncoding RNAs

Colorectal cancer (CRC) is a common malignant tumor of the digestive system, and its morbidity rates are increasing worldwide. Cancer-associated fibroblasts (CAFs), as part of the tumor microenvironment (TME), are not only closely linked to normal fibroblasts, but also can secrete a variety of substances (including exosomes) to participate in the regulation of the TME. Exosomes can play a key role in intercellular communication by delivering intracellular signaling substances (e.g., proteins, nucleic acids, non-coding RNAs), and an increasing number of studies have shown that non-coding RNAs of exosomal origin from CAFs are not only closely associated with the formation of the CRC microenvironment, but also increase the ability of CRC to grow in metastasis, mediate tumor immunosuppression, and are involved in the mechanism of drug resistance in CRC patients receiving. It is also involved in the mechanism of drug resistance after radiotherapy in CRC patients. In this paper, we review the current status and progress of research on CAFs-derived exosomal non-coding RNAs in CRC.

SLC27A2 mediates FAO in colorectal cancer through nongenic crosstalk regulation of the PPARs pathway

BACKGROUND

Peroxisome proliferator activated receptors (PPARs) are a nuclear hormone receptors superfamily that is closely related to fatty acid (FA) metabolism and tumor progression. Solute carrier family 27 member 2 (SLC27A2) is important for FA transportation and metabolism and is related to cancer progression. This study aims to explore the mechanisms of how PPARs and SLC27A2 regulate FA metabolism in colorectal cancer (CRC) and find new strategies for CRC treatment.

METHODS

Biological information analysis was applied to detect the expression and the correlation of PPARs and SLC27A2 in CRC. The protein-protein interaction (PPI) interaction networks were explored by using the STRING database. Uptake experiments and immunofluorescence staining were used to analyse the function and number of peroxisomes and colocalization of FA with peroxisomes, respectively. Western blotting and qRT‒PCR were performed to explore the mechanisms.

RESULTS

SLC27A2 was overexpressed in CRC. PPARs had different expression levels, and PPARG was significantly highly expressed in CRC. SLC27A2 was correlated with PPARs in CRC. Both SLC27A2 and PPARs were closely related to fatty acid oxidation (FAO)‒related genes. SLC27A2 affected the activity of ATP Binding Cassette Subfamily D Member 3 (ABCD3), also named PMP70, the most abundant peroxisomal membrane protein. We found that the ratios of p-Erk/Erk and p-GSK3β/GSK3β were elevated through nongenic crosstalk regulation of the PPARs pathway.

CONCLUSIONS

SLC27A2 mediates FA uptake and beta-oxidation through nongenic crosstalk regulation of the PPARs pathway in CRC. Targeting SLC27A2/FATP2 or PPARs may provide new insights for antitumour strategies.

Nanomaterials: Breaking through the bottleneck of tumor immunotherapy

Immunotherapy exerts its excellent anti-tumor effects by stimulating and enhancing the immune response of the body, and has become another important class of anti-tumor therapy besides chemotherapy, targeted therapy and radiotherapy. Various types of immunotherapeutic drugs have gained their clinical values, but the in vivo delivery of drugs still faces many challenges, such as poor tumor permeability and low tumor cell uptake rate. In recent years, owing to highly targeting properties, better biocompatibility, and easy functionalization, nanomaterials have been widely applicated in tumor treatment, especially in tumor immunotherapy. Furthermore, nanomaterials have large drug loading capacity, strong tumor targeting and easy modification, which can effectively overcome the drawbacks of traditional immunotherapy. This paper reviews the progress of nanomaterial-based tumor immunotherapy in recent years and provides a theoretical basis for exploring new nanomaterial-based tumor immunotherapy strategies.

Therapeutic challenge for immunotherapy targeting cold colorectal cancer: A narrative review

Cold colorectal tumors are not likely to trigger a robust immune response and tend to suppress the immune response. There may be three reasons. First, the complex tumor microenvironment of cold colorectal cancer (CRC) leads to tolerance and clearance of immunotherapy. Second, the modification and concealment of tumor-specific targets in cold CRC cause immune escape and immune response interruption. Finally, the difference in number and function of immune cell subsets in patients with cold CRC makes them respond poorly to immunotherapy. Therefore, we can only overcome the challenges in immunotherapy of cold CRC through in-depth research and understanding the changes and mechanisms in the above three aspects of cold CRC.