Targeting Stress Erythropoiesis Pathways in Cancer

Signaling networks guiding erythropoiesis

PURPOSE OF REVIEW

Cytokine-mediated signaling pathways, including JAK/STAT, PI3K/AKT, and Ras/MAPK pathways, play an important role in the process of erythropoiesis. These pathways are involved in the survival, proliferation, and differentiation function of erythropoiesis.

RECENT FINDINGS

The JAK/STAT pathway controls erythroid progenitor differentiation, proliferation, and survival. The PI3K/AKT signaling cascade facilitates erythroid progenitor survival, proliferation, and final differentiation. During erythroid maturation, MAPK, triggered by EPO, suppresses myeloid genes, while PI3K is essential for differentiation. Pro-inflammatory cytokines activate signaling pathways that can alter erythropoiesis like EPOR-triggered signaling, including survival, differentiation, and proliferation.

SUMMARY

A comprehensive understanding of signaling networks is crucial for the formulation of treatment approaches for hematologic disorders. Further investigation is required to fully understand the mechanisms and interactions of these signaling pathways in erythropoiesis.

Usefulness of baseline immature reticulocyte fraction to mature reticulocyte fraction ratio (IMR) as A prognostic predictor for patients with small cell lung cancer

Background

Small cell lung cancer (SCLC) has a strong invasive ability and a high degree of malignancy, so accurate prognosis prediction is crucial for making the most favorable treatment decision.Unfortunately, there is a scarcity of prognostic indicators specific to SCLC. Reticulocyte levels in blood parameters have been linked to the prognosis of various malignancies. Given SCLC's aggressive characteristics, identifying reliable prognostic markers, such as reticulocyte counts, becomes pivotal in enhancing prognostic accuracy and guiding effective therapeutic strategies.

Objective

This study aimed to evaluate the predictive power of the immature reticulocyte fraction (IRF) to mature reticulocyte fraction (MRF) ratio (IMR) for survival outcomes in patients with SCLC.

Materials and methods

A retrospective analysis was conducted on 192 patients with small cell lung cancer (SCLC). The median values of various prognostic indicators, such as IMR, IRF, MRF, reticulocyte count (RET), SII (systemic immune-inflammatory index), were utilized as cutoff points, categorizing patients into high and low groups. The Kaplan-Meier method, univariate, multivariate analyses Cox regression, and C-index were used to analyze the prognostic factors for overall survival (OS).

Results

In our cohort, 138 (71.9 %) were male, 119 (62 %) were smokers, and 82 (57.3 %) were older than 60 years old. The median survival time was 18.15 months.Higher mortality was observed in the high IMR and high IRF groups, while the high MRF group exhibited lower mortality. At the same time, mortality was lower in the high MRF group. Univariate analysis showed that smoking history (P = 0.006), tumor stage (P = 0.002), chemotherapy cycle (P = 0.014), IMR (P = 0.01), and many other factors significantly affected the prognosis of SCLC. Multivariate analysis demonstrated that elevated IMR was an independent adverse predictor of OS (P = 0.039, HR = 0.330). Spearman test confirmed that the prognostic indicators IRF, IMR, and SII were positively correlated with the overall survival rate of patients with SCLC. Kaplan-Meier analysis showed that the OS rate of patients with high IMR was significantly worse (P = 0.0096). In addition, we found that IMR was superior to IRF in distinguishing patients with different outcomes in the low and high groups (P < 0.05). Our novel integration index, combining IMR with the TNM stage system and SII index, exhibited superior prognostic value compared to the original index. Additionally, the combination of prognostic indicators IMR and SII significantly stratified stage I-II SCLC patients (P ＜0.05).

Conclusions

The prognostic index based on peripheral blood IMR stands out as an independent predictor for SCLC patients pre-treatment. Its accessibility through routine blood analysis facilitates immediate clinical application without requiring prolonged scientific research validation. The integration of IMR with the TNM score enhances survival prediction and risk stratification. Notably, when combined with the SII score, the new IMR index demonstrates significant improvements in prognostication for stage I-II small cell lung cancer.

Erythropoiesis in Cushing syndrome: sex-related and subtype-specific differences. Results from a monocentric study

CONTEXT

Cushing syndrome (CS) is associated with different hematological abnormalities. Nevertheless, conflicting data about erythropoiesis in CS have been reported. Furthermore, it is unclear whether CS sex and subtype-specific alterations in red blood cells (RBC) parameters are present.

OBJECTIVE

To investigate sex and subtype-specific changes in RBC in patients with CS at initial diagnosis and after remission.

DESIGN

Retrospective, monocentric study including 210 patients with CS (women, n = 162) matched 1:1 for sex and age to patients with pituitary microadenomas or adrenal incidentalomas (both hormonally inactive). RBC parameters were evaluated at initial diagnosis and after remission.

RESULTS

Women with CS had higher hematocrit (median 42.2 vs 39.7%), hemoglobin (14.1 vs 13.4 g/dl) and mean corpuscular volume (MCV) (91.2 vs 87.9 fl) compared to the controls (all p < 0.0001). Women with Cushing disease (CD) showed higher hematocrit, RBC and hemoglobin levels than those with ectopic Cushing (ECS) (all p < 0.005). Men with CS had lower hematocrit (42.9 vs 44.7%), RBC count (4.8 vs 5.1n*106/µl) and hemoglobin (14.2 vs 15.4 g/dl), but higher MCV (90.8 vs 87.5 fl) than controls (all p < 0.05). In men with CS, no subtype-specific differences were identified. Three months after remission hemoglobin decreased in both sexes.

CONCLUSION

CS is characterized by sexual and subtype-specific differences in RBC parameters. Compared to controls, women with CS showed higher hematocrit/hemoglobin levels, whereas men had lower hematocrit/hemoglobin, which further decreased directly after remission. Therefore, anemia should be considered as complication of CS in men. In women, differences in RBC parameters may help to differentiate CD from ECS.

Extramedullary hematopoiesis contributes to enhanced erythropoiesis during pregnancy via TGF-β signaling

Red blood cells are the predominant cellular component in human body, and their numbers increase significantly during pregnancy due to heightened erythropoiesis. CD71+ erythroid cells (CECs) are immature red blood cells, encompassing erythroblasts and reticulocytes, constitute a rare cell population primarily found in the bone marrow, although they are physiologically enriched in the neonatal mouse spleen and human cord blood. Presently, the mechanisms underlying the CECs expansion during pregnancy remain largely unexplored. Additionally, the mechanisms and roles associated with extramedullary hematopoiesis (EMH) of erythroid cells during pregnancy have yet to be fully elucidated. In this study, our objective was to examine the underlying mechanisms of erythroid-biased hematopoiesis during pregnancy. Our findings revealed heightened erythropoiesis and elevated CECs in both human and mouse pregnancies. The increased presence of transforming growth factor (TGF)-β during pregnancy facilitated the differentiation of CD34+ hematopoietic stem and progenitor cells (HSPCs) into CECs, without impacting HSPCs proliferation, ultimately leading to enhanced erythropoiesis. The observed increase in CECs during pregnancy was primarily attributed to EMH occurring in the spleen. During mouse pregnancy, splenic stromal cells were found to have a significant impact on splenic erythropoiesis through the activation of TGF-β signaling. Conversely, splenic macrophages were observed to contribute to extramedullary erythropoiesis in a TGF-β-independent manner. Our results suggest that splenic stromal cells play a crucial role in promoting extramedullary erythropoiesis and the production of CECs during pregnancy, primarily through TGF-β-dependent mechanisms.

Role of growth differentiation factor 15 in cancer cachexia (Review)

Growth differentiation factor 15 (GDF15), a member of the transforming growth factor-β family, is a stress-induced cytokine. Under normal circumstances, the expression of GDF15 is low in most tissues. It is highly expressed during tissue injury, inflammation, oxidative stress and cancer. GDF15 has been established as a biomarker in patients with cancer, and is associated with cancer cachexia (CC) and poor survival. CC is a multifactorial metabolic disorder characterized by severe muscle and adipose tissue atrophy, loss of appetite, anemia and bone loss. Cachexia leads to reductions in quality of life and tolerance to anticancer therapy, and results in a poor prognosis in cancer patients. Dysregulated GDF15 levels have been discovered in patients with CC and animal models, where they have been found to be involved in anorexia and weight loss. Although studies have suggested that GDF15 mediates anorexia and weight loss in CC through its neuroreceptor, glial cell-lineage neurotrophic factor family receptor α-like, the effects of GDF15 on CC and the potential regulatory mechanisms require further elucidation. In the present review, the characteristics of GDF15 and its roles and molecular mechanisms in CC are elaborated. The targeting of GDF15 as a potential therapeutic strategy for CC is also discussed.

Development and Characterization of a Cancer Cachexia Rat Model Transplanted with Cells of the Rat Lung Adenocarcinoma Cell Line Sato Lung Cancer (SLC)

Cancer cachexia is a complex malnutrition syndrome that causes progressive dysfunction. This syndrome is accompanied by protein and energy losses caused by reduced nutrient intake and the development of metabolic disorders. As many as 80% of patients with advanced cancer develop cancer cachexia; however, an effective targeted treatment remains to be developed. In this study, we developed a novel rat model that mimics the human pathology during cancer cachexia to elucidate the mechanism underlying the onset and progression of this syndrome. We subcutaneously transplanted rats with SLC cells, a rat lung adenocarcinoma cell line, and evaluated the rats' pathophysiological characteristics. To ensure that our observations were not attributable to simple starvation, we evaluated the characteristics under tube feeding. We observed that SLC-transplanted rats exhibited severe anorexia, weight loss, muscle atrophy, and weakness. Furthermore, they showed obvious signs of cachexia, such as anemia, inflammation, and low serum albumin. The rats also exhibited weight and muscle losses despite sufficient nutrition delivered by tube feeding. Our novel cancer cachexia rat model is a promising tool to elucidate the pathogenesis of cancer cachexia and to conduct further research on the development of treatments and supportive care for patients with this disease.

Macrophages Provide Essential Support for Erythropoiesis, and Extracellular ATP Contributes to a Erythropoiesis-Supportive Microenvironment during Repeated Psychological Stress

Psychological stress is a significant contributor to various chronic diseases and affects multiple physiological processes including erythropoiesis. This study aimed to examine the tissue-specific contributions of macrophages and extracellular ATP, as a signal of disturbed tissue homeostasis, to erythropoiesis under conditions of repeated psychological stress. Adult male BALB/c mice were subjected to 2 h daily restraint stress for seven consecutive days. Clodronate-liposomes were used to deplete resident macrophages from the bone marrow and spleen two days prior to the first restraint procedure, as well as newly recruited macrophages, every third day for the duration of the experiment. Repeated stress induced a considerable increase in the number of erythroid progenitor cells as well as in the percentage of CD71+/Ter119+ and CD71-/Ter119+ cells in the bone marrow and spleen. Macrophage depletion completely abolished the stimulative effect of repeated stress on immature erythroid cells, and prevented stress-induced increases in ATP levels, P2X7 receptor (P2X7R) expression, and ectonucleotidase CD39 activity and expression in the bone marrow and spleen. The obtained results demonstrate the stimulative effects of repeated stress on erythroid cells, extracellular ATP levels, P2X7R expression, CD39 activity and expression within the bone marrow and spleen, as well as the essential role of macrophages in stress-induced changes.

Synergistic immunotherapy targeting cancer-associated anemia: prospects of a combination strategy

Cancer-associated anemia promotes tumor progression, leads to poor quality of life in patients with cancer, and even obstructs the efficacy of immune checkpoint inhibitors therapy. However, the precise mechanism for cancer-associated anemia remains unknown and the feasible strategy to target cancer-associated anemia synergizing immunotherapy needs to be clarified. Here, we review the possible mechanisms of cancer-induced anemia regarding decreased erythropoiesis and increased erythrocyte destruction, and cancer treatment-induced anemia. Moreover, we summarize the current paradigm for cancer-associated anemia treatment. Finally, we propose some prospective paradigms to slow down cancer-associated anemia and synergistic the efficacy of immunotherapy. Video Abstract.

Interplay between stress and cancer-A focus on inflammation

Stress is an integral part of life. While acute responses to stress are generally regarded as beneficial in dealing with immediate threats, chronic exposure to threatening stimuli exerts deleterious effects and can be either a contributing or an aggravating factor for many chronic diseases including cancer. Chronic psychological stress has been identified as a significant factor contributing to the development and progression of cancer, but the mechanisms that link chronic stress to cancer remain incompletely understood. Psychological stressors initiate multiple physiological responses that result in the activation of the hypothalamic-pituitary-adrenal (HPA) axis, sympathetic nervous system, and the subsequent changes in immune function. Chronic stress exposure disrupts the homeostatic communication between the neuroendocrine and immune systems, shifting immune signaling toward a proinflammatory state. Stress-induced chronic low-grade inflammation and a decline in immune surveillance are both implicated in cancer development and progression. Conversely, tumor-induced inflammatory cytokines, apart from driving a tumor-supportive inflammatory microenvironment, can also exert their biological actions distantly via circulation and therefore adversely affect the stress response. In this minireview, we summarize the current findings on the relationship between stress and cancer, focusing on the role of inflammation in stress-induced neuroendocrine-immune crosstalk. We also discuss the underlying mechanisms and their potential for cancer treatment and prevention.