Hypoxia-Inducible Factor-2α Signaling in the Skeletal System

Insights into Sorafenib resistance in hepatocellular carcinoma: Mechanisms and therapeutic aspects

The most prevalent primary hepatic cancer, hepatocellular carcinoma (HCC), has a bad prognosis. HCC prevalence and related deaths have increased in recent decades. Food and Drug Administration (FDA) has licensed Sorafenib as a first-line treatment for individuals with advanced HCC. Despite this, some clinical studies indicate that a significant percentage of liver cancer patients exhibit insensitivity to sorafenib. Furthermore, the overall effectiveness of sorafenib is far from adequate, and the number of patients who benefit from therapy is low. In recent years, many researchers have focused on the mechanisms underlying sorafenib resistance. Acquired resistance to sorafenib in HCC cells has been reported to be facilitated by dysregulation of signal transducer and activator of transcription 3 (STAT3) activation, angiogenesis, autophagy, hypoxia-induced pathways, epithelial-mesenchymal transition (EMT), cancer stem cells (CSCs), ferroptosis, and non-coding RNAs (ncRNAs). Recent clinical trials, including comparisons of sorafenib with immune checkpoint inhibitors like tislelizumab, have shown promise in improving patient outcomes. Additionally, combination therapies targeting complementary pathways are under investigation to overcome resistance and enhance treatment efficacy. The limitation of Sorafenib's effectiveness has been partially but not completely clarified. Furthermore, while certain regimens have demonstrated positive results, more clinical trials are required to confirm them. Future research should focus on identifying predictive biomarkers for therapy response, targeting the tumor microenvironment, and exploring novel therapeutic agents and personalized medicine strategies. A deeper understanding of these mechanisms will be essential for developing more effective therapeutic approaches and improving the prognosis of patients with advanced HCC. This article discusses strategies that may be employed to enhance the success of treatment and summarizes new research on the possible pathways that lead to sorafenib resistance.

Angelica sinensis polysaccharides promote extramedullary stress erythropoiesis via ameliorating splenic glycolysis and EPO/STAT5 signaling-regulated macrophages

Conventional treatments exhibit various side effects on chronic stress anemia. Extramedullary stress erythropoiesis is a compensatory mechanism, which may effectively counteract anemia. Angelica sinensis polysaccharides (ASP) are the main active ingredient found in Angelica sinensis and exhibit antioxidant and hematopoietic effects. However, the effects of ASP on extramedullary stress erythropoiesis remain to be unclear. Here, we demonstrated the protective effects of ASP on chemotherapeutic drug 5-fluorouracil (5-FU)-induced decline in peripheral blood parameters such as RBC counts, HGB, HCT, and MCH, and the decline of BFU-E colony enumeration in the bone marrow. Meanwhile, ASP promoted extramedullary erythropoiesis, increasing cellular proliferation in the splenic red pulp and cyclin D1 protein expression, abrogating phase G0/G1 arrest of c-kit+ cells in mouse spleen. RT-qPCR and immunohistochemistry further revealed that ASP increased macrophage chemokine Ccl2 genetic expression and the number of F4/80+ macrophages in the spleen. The colony-forming assay showed that ASP significantly increased splenic BFU-E. Furthermore, we found that ASP facilitated glycolytic genes including Hk2, Pgk1, Pkm, Pdk1, and Ldha via PI3K/Akt/HIF2α signaling in the spleen. Subsequently, ASP declined pro-proinflammatory factor IL-1β, whereas upregulating erythroid proliferation-associated genes Gdf15, Bmp4, Wnt2b, and Wnt8a. Moreover, ASP facilitated EPO/STAT5 signaling in splenic macrophages, thus enhancing erythroid lineage Gata2 genetic expression. Our study indicated that ASP may improve glycolysis, promoting the activity of splenic macrophages, subsequently promoting erythroid progenitor cell expansion. Additionally, ASP facilitates erythroid differentiation via macrophage-mediated EpoR/STAT5 signaling; suggesting it might be a promising strategy for stress anemia treatment.

Effects of GBT1118, a voxelotor analog, on bone disease in sickle cell disease mice

We assessed the effect of GBT1118, a sickle hemoglobin polymerization inhibitor on bone loss in humanized sickle cell disease (SCD) mice. Healthy control (Ctrl) 4-months-old female and male mice were fed Vehicle-chow for 2-months, while SCD mice were fed Vehicle-chow or GBT1118-chow. By micro-CT, GBT1118 significantly increased femur metaphyseal trabecular thickness (Tb.Th) and tissue mineral density (TMD), and significantly decreased trabecular spacing in female SCD mice. In SCD male mice, there was significant reduction in epiphyseal trabecular bone volume fraction (BV/TV), Tb.Th and TMD and GBT1118 significantly increased BV/TV and TMD but not Tb.Th. A significant decrease in cortical area fraction in SCD female mice was rescued by GBT1118 but not SCD males. Markedly decreased mineralized femur trabeculae in SCD females and males was partially rescued by GBT1118. Bone histomorphometry of femurs demonstrated significantly decreased bone formation parameters and increased bone resorption parameters in SCD mice of both sex that were rescued by GBT1118. Significant alteration in bone and hypoxia related genes of SCD mice of both sexes were differentially modulated by GBT1118. We conclude that "a sickle hemoglobin polymerization inhibitor" might be efficacious in improving some parameters of SCD bone loss.

Recent progress in the development of hypoxia-inducible factor 2α (HIF-2α) modulators: Inhibitors, agonists, and degraders (2009-2024)

Hypoxia-inducible factor 2α (HIF-2α) is a critical transcription factor that regulates cellular responses under hypoxic conditions. In situations of insufficient oxygen supply or patients with Von Hippel-Lindau (VHL) mutations, HIF-2α accumulates and forms a heterodimeric complex with aryl hydrocarbon receptor nuclear translocator (ARNT, or HIF-β). This complex further binds to coactivator p300 and interacts with hypoxia response elements (HREs) on the DNA of downstream target genes, regulating the transcription of a variety of genes (e.g. VEGFA, CCND1, CXCR4, SLC2A1, etc) involved in various processes like angiogenesis, mitochondrial metabolism, cell proliferation, and metastasis. Targeting HIF-2α holds great promise for effectively addressing solid tumors associated with aberrant oxygen-sensing pathways and hypoxia mechanisms, offering broad application prospects. In this review, we provide an overview of recent advancements (2009-2024) in HIF-2α modulators such as inhibitors, agonists, and degraders for cancer therapy. Additionally, we discuss in detail the challenges and future directions regarding HIF-2α modulators.

The impact of diabetes, anemia, and renal function in the relationship between osteoporosis and fasting blood glucose among Taiwanese women: a cross-sectional study

BACKGROUND

The aim of this study was to investigate the association between fasting blood glucose and osteoporosis in women with diabetes, anemia, and renal function.

METHODS

The medical records of women who underwent a general health examination at a regional hospital in southern Taiwan were retrospectively reviewed. Logistic regression analysis was performed to assess the association between osteoporosis and fasting blood glucose separately for the eight subgroups (diabetes or non-diabetes, anemia or non-anemia, normal or decreased renal function), adjusting for other clinical characteristics and laboratory findings.

RESULTS

A total of 11,872 women were included in the study. Among women with diabetes, anemia, and decreased renal function, an increment of 10 mg/dL in fasting blood glucose was associated with an increased risk of osteoporosis (adjusted odds ratio [aOR] = 1.57, p = 0.004). Among women without diabetes, fasting blood glucose was significantly associated with an increased risk of osteoporosis in those with anemia and normal renal function (OR = 1.14, p = 0.023) and those without anemia and normal renal function (OR = 1.04, p = 0.015), but these associations were not significant after adjusting for other covariates.

CONCLUSIONS

Higher fasting blood glucose levels in women with diabetes, anemia, and decreased renal function were associated with an increased risk of osteoporosis. Clinicians should be vigilant about glucose control in patients with diabetes to reduce the risk of fracture.

Iron Deficiency and Iron Deficiency Anemia: Potential Risk Factors in Bone Loss

Iron is one of the essential mineral elements for the human body and this nutrient deficiency is a worldwide public health problem. Iron is essential in oxygen transport, participates in many enzyme systems in the body, and is an important trace element in maintaining basic cellular life activities. Iron also plays an important role in collagen synthesis and vitamin D metabolism. Therefore, decrease in intracellular iron can lead to disturbance in the activity and function of osteoblasts and osteoclasts, resulting in imbalance in bone homeostasis and ultimately bone loss. Indeed, iron deficiency, with or without anemia, leads to osteopenia or osteoporosis, which has been revealed by numerous clinical observations and animal studies. This review presents current knowledge on iron metabolism under iron deficiency states and the diagnosis and prevention of iron deficiency and iron deficiency anemia (IDA). With emphasis, studies related to iron deficiency and bone loss are discussed, and the potential mechanisms of iron deficiency leading to bone loss are analyzed. Finally, several measures to promote complete recovery and prevention of iron deficiency are listed to improve quality of life, including bone health.