Platelets in the tumor microenvironment and their biological effects on cancer hallmarks

Platelets and diseases: signal transduction and advances in targeted therapy

Platelets are essential anucleate blood cells that play pivotal roles in hemostasis, tissue repair, and immune modulation. Originating from megakaryocytes in the bone marrow, platelets are small in size but possess a highly specialized structure that enables them to execute a wide range of physiological functions. The platelet cytoplasm is enriched with functional proteins, organelles, and granules that facilitate their activation and participation in tissue repair processes. Platelet membranes are densely populated with a variety of receptors, which, upon activation, initiate complex intracellular signaling cascades. These signaling pathways govern platelet activation, aggregation, and the release of bioactive molecules, including growth factors, cytokines, and chemokines. Through these mechanisms, platelets are integral to critical physiological processes such as thrombosis, wound healing, and immune surveillance. However, dysregulated platelet function can contribute to pathological conditions, including cancer metastasis, atherosclerosis, and chronic inflammation. Due to their central involvement in both normal physiology and disease, platelets have become prominent targets for therapeutic intervention. Current treatments primarily aim to modulate platelet signaling to prevent thrombosis in cardiovascular diseases or to reduce excessive platelet aggregation in other pathological conditions. Antiplatelet therapies are widely employed in clinical practice to mitigate clot formation in high-risk patients. As platelet biology continues to evolve, emerging therapeutic strategies focus on refining platelet modulation to enhance clinical outcomes and prevent complications associated with platelet dysfunction. This review explores the structure, signaling pathways, biological functions, and therapeutic potential of platelets, highlighting their roles in both physiological and pathological contexts.

Association of non-insulin-based insulin resistance indices, mean platelet volume and prostate cancer: a cross-sectional study

PURPOSE

Insulin resistance and prostate cancer (PCa) association results remain controversial. However, few studies have compared the role of various non-insulin-based insulin resistance (NI-IR) indices and mean platelet volume (MPV) in PCa.

METHODS

We conducted a cross-sectional study, the case group included 354 patients with PCa, and the control group included 1,498 non-PCa participants. We performed inverse probability weighting to reduce the impact of differences in baseline information between the case and control groups on results. Weighted logistic regression analysis for assessing the relationship between NI-IR indices and PCa risk. Fitting 4-point restricted cubic spline (RCS) plots to show the trend of NI-IR indices with PCa risk. The interaction between insulin resistance and platelet volume based on generalized additive model (GAM) to reveal the impact of the interaction between insulin resistance and cardiovascular risk on PCa. In the end, we performed three sensitivity analyses to verify the stability of results.

RESULTS

Weighted logistic regression analysis revealed that all NI-IR indices were associated with PCa. When NI-IR indices were evaluated as continuous variables, in the all variables adjusted model (model 3), the adjusted OR of ZJU index was 1.337 (95%CI: 1.296-1.379), the adjusted OR of TyG index was 5.300 (95%CI:4.208-6.675), the adjusted OR of TG/HDL-c was 1.431 (95%CI:1.335-1.534), and the adjusted OR of METS-IR was 1.129 (95%CI:1.110-1.149). When NI-IR indices were analyzed as categorical variables, also in model 3, using Q1 as reference, the adjusted OR of ZJU index in Q5 was 15.592 (95%CI:10.809-22.492), the adjusted OR of TyG index in Q5 was 7.306 (95%CI:5.182-10.301), the adjusted OR of TG/HDL-c in Q5 was 4.790 (95%CI:3.459-6.632), and the adjusted OR of METS-IR in Q5 was 9.844 (95%CI:6.862-14.121). RCS displayed that PCa risk tended to increase as the ZJU index, TyG index, TG/HDL-c, and METS-IR increased. The interaction test based on the GAM indicated that the value of the interaction between TG/HDL-c and MPV on the PCa risk was χ2 = 6.924(P = 0.009). With the increase in TG/HDL-c and the decrease in MPV, the PCa risk progressively increases. The sensitivity analysis further confirmed the robustness of the results.

CONCLUSIONS

NI-IR indices were associated with an increased PCa risk. The interaction between MPV and insulin resistance may further contribute to the PCa risk.

Day + 100 bone marrow megakaryocyte count predicts transplant outcome in patients with high-risk myelodysplastic syndrome and acute leukemia

Megakaryocytes (MKs), the precursor cells of platelets, have essential roles in a variety of pathophysiological processes in the bone marrow (BM) niche. Megakaryocytes maintain hematopoietic stem cell microenvironment through inflammatory and immunological responses. The primary objective of this research was to investigate the clinical impact of BM-MK counts in high-risk myelodysplastic syndrome and acute leukemia patients who underwent allogeneic hematopoietic stem cell transplantation (alloHSCT). Three hundred and forty-six patients (median age, 42 (15-71) years; male/female, 207/139) participated in the study. Based on the BM-MK counts on day + 100 of alloHSCT, the study population was classified into normal/high-MK+100 and low-MK+100 groups. The probabilities of progression-free survival (PFS) and overall survival (OS) were significantly better in the normal/high-MK+100 group (p < 0.001, p < 0.001). Nonrelapse mortality was found to be reduced in the same group of patients (p = 0.012). BM-MK+100 count, which was indicated to be a predictor for relapse after alloHSCT (p = 0.018), represented a considerable impact on PFS and OS (p = 0.017, p = 0.009). Megakaryocytes have regulatory roles in association with a comprehensive cytokine network in the BM microenvironment. Although the localization of MKs may be determinative for their spectrum of efficacy, distinct biological subgroups may also help to clarify the heterogeneity of their functional features. Prospective efforts in larger populations are required to illuminate the potential prognostic role of MKs in alloHSCT recipients.

The role of platelets in cancer: from their influence on tumor progression to their potential use in liquid biopsy

Platelets, anucleate blood cells essential for hemostasis, are increasingly recognized for their role in cancer, challenging the traditional notion of their sole involvement in blood coagulation. It has been demonstrated that platelets establish bidirectional communication with tumor cells, contributing to tumor progression and metastasis through diverse molecular mechanisms such as modulation of proliferation, angiogenesis, epithelial-mesenchymal transition, resistance to anoikis, immune evasion, extravasation, chemoresistance, among other processes. Reciprocally, cancer significantly alters platelets in their count and composition, including mRNA, non-coding RNA, proteins, and lipids, product of both internal synthesis and the uptake of tumor-derived molecules. This phenomenon gives rise to tumor-educated platelets (TEPs), which are emerging as promising tools for the development of liquid biopsies. In this review, we provide a detailed overview of the dynamic roles of platelets in tumor development and progression as well as their use in diagnosis and prognosis. We also provide our view on current limitations, challenges and future research areas, including the need to design more efficient strategies for their isolation and analysis, as well as the validation of their sensitivity and specificity through large-scale and rigorous clinical trials. This research will not only enable the evaluation of their clinical viability but could also open new opportunities to enhance diagnostic accuracy and develop personalized treatments in oncology.

The power of many: Multilevel targeting of representative chemokine and metabolite GPCRs in personalized cancer therapy

G protein-coupled receptors (GPCRs) are vital cell surface receptors that govern a myriad of physiological functions. Despite their crucial role in regulating antitumor immunity and tumorigenesis, therapeutic applications targeting GPCRs in oncology are currently limited. This review offers a focused examination of selected protumorigenic chemokine and metabolite-sensing GPCRs. Specifically, the review highlights five GPCRs able to orchestrate tumor immunobiology at three main levels: tumor immunity, cancer cell expansion, and blood vessel development. The review culminates by illuminating emerging therapies and discussing innovative strategies to harness the full potential of GPCR-targeted treatments, by applying a multireceptor and patient-specific logic.

Predictive and Prognostic Value of Inflammatory and Nutritional Indexes in Patients with Breast Cancer Receiving Neoadjuvant Chemotherapy

Background and Objectives: Neoadjuvant chemotherapy (NAC) improves survival by increasing pathologic complete response (pCR). Blood-based indexes have been studied in breast cancer for predicting pCR and prognosis, but the results are conflicting. We aimed to assess the impact of inflammatory and nutritional indexes on pCR and survival. Materials and Methods: We retrospectively analyzed 304 patients. Pre-NAC laboratory data were used to calculate their neutrophil-to-lymphocyte ratios (NLR), pan-immune inflammation values (PIV), lactate dehydrogenase-albumin ratios (LAR), and prognostic nutritional indexes. The optimal cut-off values were determined through an analysis of the receiver operating characteristic curve. Survival analyses were performed using the Kaplan-Meier method. Multivariate regression analyses were performed to reveal the factors predicting pCR. Univariate and multivariate survival analyses were conducted to identify prognostic factors predicting survival. Results: The median follow-up was 38.5 months. pCR was achieved in 41.4% of the patients. In the univariate analyses, the NLR (p = 0.032) and PIV (p = 0.002) were indexes associated with pCR. In the multivariate analysis, the PIV (p = 0.008) was the only index significantly correlated with pCR. According to the multivariate Cox regression analyses, clinical stage 3 (p = 0.032), a pathologic response other than pCR (p = 0.021), and a high LAR (≥4.72) (p = 0.002) were correlated with increased recurrence risk. The univariate Cox regression analyses revealed that failure to achieve pCR (p = 0.037) and the presence of a high LAR (p = 0.044) were significant predictors of overall survival. However, the multivariate analyses failed to identify any significant predictors of death. Conclusions: We found that the PIV was more effective than the other indexes in predicting pCR. To our knowledge, this study is the first to determine an association between the LAR and disease-free survival in patients with breast cancer receiving NAC. We concluded that a high LAR was a poor prognostic factor, especially in patients without a pCR. Therefore, close postoperative monitoring and the intensification of adjuvant treatment should be considered for these patients. However, further studies are needed to confirm our findings.

Development and Validation of an Inflammation-Combined Prognostic Index (ICPI)-Based Nomogram for Predicting Overall Survival in Gastric Cancer

Purpose

This study aims to investigate the correlation between a novel integrated inflammatory marker: The inflammation-combined prognostic index (ICPI), combining NLR, PLR, and MLR, with the clinicopathological characteristics and overall survival (OS) of gastric cancer (GC).

Patients and Methods

Data from 876 patients with GC were retrospectively analyzed from January 1, 2017, to April 30, 2023. PSM was employed to mitigate confounding factors between groups. Receiver operating characteristic (ROC) curves were utilized to determine the optimal cutoff value. Univariate, LASSO, and multivariate regression analyses were executed. Subsequently, a nomogram for predicting OS was developed and validated.

Results

The cohort with a poor prognosis exhibited significantly elevated levels of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), and ICPI (P<0.001). Similarly, higher levels of NLR, PLR, MLR, and ICPI were associated with a poorer prognosis (P<0.001). Following regression analysis, ICPI, T-stage, lymph node ratio (LNR), and primary site were identified as independent risk factors affecting OS. A nomogram was constructed based on these factors to predict 1-, 3-, and 5-year OS, yielding C-indexes of 0.8 and 0.743 for the training and validation sets, respectively. The calibration curves demonstrated close alignment between predicted and actual results, indicating high predictive accuracy. Moreover, the decision curve underscored the practical utility of the model.

Conclusion

The new inflammatory parameter ICPI integrates NLR, PLR and MLR. The ICPI-based nomogram and web calculator accurately predict OS in patients with GC.

Breast Tumor Metastasis and Its Microenvironment: It Takes Both Seed and Soil to Grow a Tumor and Target It for Treatment

Metastasis remains a major challenge in treating breast cancer. Breast tumors metastasize to organ-specific locations such as the brain, lungs, and bone, but why some organs are favored over others remains unclear. Breast tumors also show heterogeneity, plasticity, and distinct microenvironments. This contributes to treatment failure and relapse. The interaction of breast cancer cells with their metastatic microenvironment has led to the concept that primary breast cancer cells act as seeds, whereas the metastatic tissue microenvironment (TME) is the soil. Improving our understanding of this interaction could lead to better treatment strategies for metastatic breast cancer. Targeted treatments for different subtypes of breast cancers have improved overall patient survival, even with metastasis. However, these targeted treatments are based upon the biology of the primary tumor and often these patients' relapse, after therapy, with metastatic tumors. The advent of immunotherapy allowed the immune system to target metastatic tumors. Unfortunately, immunotherapy has not been as effective in metastatic breast cancer relative to other cancers with metastases, such as melanoma. This review will describe the heterogeneic nature of breast cancer cells and their microenvironments. The distinct properties of metastatic breast cancer cells and their microenvironments that allow interactions, especially in bone and brain metastasis, will also be described. Finally, we will review immunotherapy approaches to treat metastatic breast tumors and discuss future therapeutic approaches to improve treatments for metastatic breast cancer.

Impact of platelet-derived mitochondria transfer in the metabolic profiling and progression of metastatic MDA-MB-231 human triple-negative breast cancer cells

Introduction: An active role of platelets in the progression of triple-negative breast cancer (TNBC) cells has been described. Even the role of platelet-derived extracellular vesicles on the migration of MDA-MB-231 cells has been reported. Interestingly, upon activation, platelets release functional mitochondria into the extracellular environment. However, the impact of these platelet-derived mitochondria on the metabolic properties of MDA-MB-231 cells remains unclear. Methods: MDA-MB-231 and MDA-MB-231-Rho-0 cells were co-cultured with platelets, which were isolated from donor blood. Mitochondrial transfer was assessed through confocal microscopy and flow cytometry, while metabolic analyses were conducted using a Seahorse XF HS Mini Analyzer. The mito-chondrial DNA (mtDNA) copy number was determined via quantitative PCR (qPCR) following platelet co-culture. Finally, cell proliferation and colony formation assay were performed using crystal violet staining. Results and Discussion: We have shown that platelet-derived mitochondria are internalized by MDA-MB-231 cells in co-culture with platelets, increasing ATP production, oxygen (O2) consumption rate (OCR), cell proliferation, and metabolic adaptability. Additionally, we observed that MDA-MB-231 cells depleted from mtDNA restore cell proliferation in uridine/pyruvate-free cell culture medium and mitochondrial O2 consumption after co-culture with platelets, indicating a reconstitution of mtDNA facilitated by platelet-derived mitochondria. In conclusion, our study provides new insights into the role of platelet-derived mitochondria in the metabolic adaptability and progression of metastatic MDA-MB-231 TNBC cells.

The critical role of platelet in cancer progression and metastasis

Platelets play a crucial role in cancer blood metastasis. Various cancer-related factors such as Toll-like receptors (TLRs), adenosine diphosphate (ADP) or extracellular matrix (ECM) can activate these small particles that function in hemostasis and thrombosis. Moreover, platelets induce Epithelial Mesenchymal Transition (EMT) to promote cancer progression and invasiveness. The activated platelets protect circulating tumor cells from immune surveillance and anoikis. They also mediate tumor cell arrest, extravasation and angiogenesis in distant organs through direct or indirect modulation, creating a metastatic microenvironment. This review summarizes the recent advances and progress of mechanisms in platelet activation and its interaction with cancer cells in metastasis.

Full spectrum flow cytometry-powered comprehensive analysis of PBMC as biomarkers for immunotherapy in NSCLC with EGFR-TKI resistance

BACKGROUND

Clinical studies suggest that immune checkpoint inhibitor (ICI) monotherapy has limited benefits in non-small cell lung cancer (NSCLC) patients after epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) failure. However, data about efficacy of ICI plus chemotherapy remain controversial, probably attributed to the heterogeneity among such population, and robust efficacy biomarkers are urgent to explore.

METHODS

A total of 60 eligible patients who received ICI plus chemotherapy after EGFR-TKI treatment failure were enrolled, 24 of whom peripheral blood mononuclear cell (PBMC) samples were collected at baseline and after 2 cycles of treatment. We have designed a 23-color-antibody panel to detect PBMC by full spectrum flow cytometry.

RESULTS

For EGFR-TKI resistant NSCLC patients: 1) ICI plus chemotherapy achieved an objective response rate (ORR) of 21.7% and a median progression-free survival (PFS) of 6.4 months. 2) clinical characteristics associated with worse efficacy included liver metastasis and platelet-to-lymphocyte ratio (PLR) > 200. 3) the proportion of immune cell subset associated with better efficacy was higher baseline effective CD4⁺T cells (E4). 4) the baseline expression of immune checkpoint proteins (ICPs) on cell subsets associated with better efficacy included: higher expression of CD25 on dendritic cells (DC) and central memory CD8⁺T cells (CM8), and higher expression of Lymphocyte activation gene 3 (LAG-3) on effective memory CD8⁺T cells (EM8). 5) the expression of ICPs after 2 cycles of treatment associated with better efficacy included: higher expression of CD25 on CD8⁺T/EM8 /natural killer (NK) cells. 6) the dynamic changes of ICPs expression associated with worse efficacy included: significantly decrease of T cell immunoglobulin and ITIM domain (TIGIT) expression on regular T cells (Tregs) and decrease of V-domain immunoglobulin suppressor of T cell activation (VISTA) expression on Th1. 7) a prediction model for the efficacy of ICI plus chemotherapy was successfully constructed with a sensitivity of 62.5%, specificity of 100%, and area under curve (AUC) = 0.817.

CONCLUSIONS

Some EGFR-TKI-resistant NSCLC patients could indeed benefit from ICI plus chemotherapy, but most patients are primary resistant to immunotherapy. Comprehensive analysis of peripheral immune cells using full spectrum flow cytometry showed that compared to the proportion of cell subsets, the expression type and level of ICPs on immune cells, especially CD25, were significantly correlated with the efficacy of immunotherapy.

Mitochondria-derived cell-to-cell communication

In addition to their intracellular mobility, mitochondria and their components can exist outside the cells from which they originate. As a result, they are capable of acting on non-parental distant cells and mediate intercellular communication in physiological conditions and in a variety of pathologies. It has recently been demonstrated that this horizontal transfer governs a wide range of biological processes, such as tissue homeostasis, the rescue of injured recipient cells, and tumorigenesis. In addition, due to mitochondria's bacterial ancestry, they and their components can be recognized as damage-associated molecular patterns (DAMPs) by the immune cells, leading to inflammation. Here, we provide an overview of the most current and significant findings concerning the different structures of extracellular mitochondria and their by-products and their functions in the physiological and pathological context. This account illustrates the ongoing expansion of our understanding of mitochondria's biological role and functions in mammalian organisms.

Platelet Metabolic Flexibility: A Matter of Substrate and Location

Platelets are cellular elements that are physiologically involved in hemostasis, inflammation, thrombotic events, and various human diseases. There is a link between the activation of platelets and their metabolism. Platelets possess considerable metabolic versatility. Although the role of platelets in hemostasis and inflammation is known, our current understanding of platelet metabolism in terms of substrate preference is limited. Platelet activation triggers an oxidative metabolism increase to sustain energy requirements better than aerobic glycolysis alone. In addition, platelets possess extra-mitochondrial oxidative phosphorylation, which could be one of the sources of chemical energy required for platelet activation. This review aims to provide an overview of flexible platelet metabolism, focusing on the role of metabolic compartmentalization in substrate preference, since the metabolic flexibility of stimulated platelets could depend on subcellular localization and functional timing. Thus, developing a detailed understanding of the link between platelet activation and metabolic changes is crucial for improving human health.