Sphingosine kinase 1: a new modulator of hypoxia inducible factor 1alpha during hypoxia in human cancer cells

Unveiling the metabolic landscape of pulmonary hypertension: insights from metabolomics

Pulmonary hypertension (PH) is regarded as cardiovascular disease with an extremely poor prognosis, primarily due to irreversible vascular remodeling. Despite decades of research progress, the absence of definitive curative therapies remains a critical challenge, leading to high mortality rates. Recent studies have shown that serious metabolic disorders generally exist in PH animal models and patients of PH, which may be the cause or results of the disease. It is imperative for future research to identify critical biomarkers of metabolic dysfunction in PH pathophysiology and to uncover metabolic targets that could enhance diagnostic and therapeutic strategies. Metabolomics offers a powerful tool for the comprehensive qualitative and quantitative analysis of metabolites within specific organisms or cells. On the basis of the findings of the metabolomics research on PH, this review summarizes the latest research progress on metabolic pathways involved in processes such as amino acid metabolism, carbohydrate metabolism, lipid metabolism, and nucleotide metabolism in the context of PH.

Hepatic Arterial Infusion Chemotherapy vs Transcatheter Arterial Chemoembolization as Adjuvant Therapy Following Surgery for MVI-Positive Hepatocellular Carcinoma: A Multicenter Propensity Score Matching Analysis

Background

Microvascular invasion (MVI) is a significant pathological feature in hepatocellular carcinoma (HCC), adjuvant hepatic arterial infusion chemotherapy (a-HAIC) and adjuvant transcatheter arterial chemoembolization (a-TACE), are commonly used for HCC patients with MVI. This study aims to evaluate the efficacies of two adjuvant therapies after surgical treatment for HCC, compare them, and identify the significant factors.

Methods

Clinical data from two randomized controlled trials involving HCC patients with MVI after surgical treatment were retrospectively reviewed. Propensity score matching (PSM) analysis was performed to balance baseline differences between patients who received a-HAIC or a-TACE, and control groups who underwent hepatectomy alone. Disease-free survival (DFS) and overall survival (OS) rates were compared.

Results

In total of 549 patients were collected from two randomized controlled trials. Using the PSM and Kaplan-Meier method, the median DFS of the a-HAIC, a-TACE, and control groups was 63.2, 21.7, and 11.2 months (P<0.05). The a-HAIC group show significantly better 1-, 3-, and 5-year OS rates compared to the a-TACE and control groups (96.3%, 80.0%, 72.8% vs 84.4%, 57.0%, 29.8% vs 84.5%, 62.8%, 53.4%, P<0.05). But the OS rates of a-TACE and control groups showed no significant difference (P=0.279). Multivariate analysis identified a-HAIC (HR=0.449, P=0.000) and a-TACE (HR=0.633, P=0.007) as independent protective factors. For OS, a-HAIC (HR=0.388, P=0.003) was identified as an independent protective factor, too.

Conclusion

Compared to a-TACE and the control group, a-HAIC demonstrated greater benefits in preventing tumor recurrence and improving survival in HCC patients with MVI.

Development and Validation of a Risk Prediction Algorithm for Evaluating the Efficacy of Postoperative Adjuvant TACE Therapy for Hepatocellular Carcinoma

BACKGROUND AND PURPOSE

There is a lack of a reliable outcome prediction model for patients evaluating the feasibility of postoperative adjuvant transarterial chemoembolization (PATACE) therapy. Our goal was to develop an easy-to-use tool specifically for these patients.

METHODS

From January 2013 to June 2017, patients with hepatocellular carcinoma from the Liver Center of the First Affiliated Hospital of Chongqing Medical University received postoperative adjuvant Transarterial chemoembolization (TACE) therapy after liver cancer resection. A Cox proportional hazards model was established for these patients, followed by internal validation (enhanced bootstrap resampling technique) to further evaluate the predictive performance and discriminanceevaluate the predictive performance and discriminance, and compare it with other predictive models. The prognostic factors considered included tumour number, maximum tumor diameter, Edmondson-Steiner (ES) grade, Microvascular invasion (MVI) grade, Ki67, age, sex, hepatitis B surface antigen, cirrhosis, Alpha-fetoprotein (AFP), Albumin-bilirubin (ALBI) grade, Childpugh grade, body mass index (BMI), Neutrophil-lymphocyte ratio (NLR), Platelet-to-lymphocyte ratio (PLR).

RESULTS

The endpoint of the study was overall survival. The median overall survival was 36 (95%CI: 34.0-38.0) months, with 1-year, 2-year and 3-year survival rates being 96.3%, 84.0% and 75.3%, respectively. Tumour number, MVI grade, and BMI was incorporated into the model, which had good differentiation and accuracy. Internal validation (enhanced bootstrap) suggested that Harrell's C statistic is 0.72. The model consistently outperforms other currently available models.

CONCLUSION

This model may be an easy-to-use tool for screening patients suitable for PA-TACE treatment and guiding the selection of clinical protocols. But further research and external validation are required.

The role of HIF in angiogenesis, lymphangiogenesis, and tumor microenvironment in urological cancers

Typically associated with solid tumors, hypoxia contributes to tumor angiogenesis and lymphangiogenesis through various molecular mechanisms. Accumulating studies indicate that hypoxia-inducible factor is the key transcription factor coordinating endothelial cells to respond to hypoxia in urological cancers, mainly renal cell carcinoma, prostate cancer, and bladder cancer. Moreover, it has been suggested that tumor hypoxia in tumor microenvironment simultaneously recruits stromal cells to suppress immune activities. This review summarizes the mechanisms by which HIF regulates tumorigenesis and elaborates on the associations between HIF and angiogenesis, lymphangiogenesis, and tumor microenvironment in urological cancers.

Engineered Lipidic Nanomaterials Inspired by Sphingomyelin Metabolism for Cancer Therapy

Sphingomyelin (SM) and its metabolites are crucial regulators of tumor cell growth, differentiation, senescence, and programmed cell death. With the rise in lipid-based nanomaterials, engineered lipidic nanomaterials inspired by SM metabolism, corresponding lipid targeting, and signaling activation have made fascinating advances in cancer therapeutic processes. In this review, we first described the specific pathways of SM metabolism and the roles of their associated bioactive molecules in mediating cell survival or death. We next summarized the advantages and specific applications of SM metabolism-based lipidic nanomaterials in specific cancer therapies. Finally, we discussed the challenges and perspectives of this emerging and promising SM metabolism-based nanomaterials research area.

Targeting Sphingosine 1-Phosphate Metabolism as a Therapeutic Avenue for Prostate Cancer

Prostate cancer (PC) is the second most common cancer in men worldwide. More than 65% of men diagnosed with PC are above 65. Patients with localized PC show high long-term survival, however with the disease progression into a metastatic form, it becomes incurable, even after strong radio- and/or chemotherapy. Sphingosine 1-phosphate (S1P) is a bioactive lipid that participates in all the steps of oncogenesis including tumor cell proliferation, survival, migration, invasion, and metastatic spread. The S1P-producing enzymes sphingosine kinases 1 and 2 (SK1 and SK2), and the S1P degrading enzyme S1P lyase (SPL), have been shown to be highly implicated in the onset, development, and therapy resistance of PC during the last 20 years. In this review, the most important studies demonstrating the role of S1P and S1P metabolic partners in PC are discussed. The different in vitro, ex vivo, and in vivo models of PC that were used to demonstrate the implication of S1P metabolism are especially highlighted. Furthermore, the most efficient molecules targeting S1P metabolism that are under preclinical and clinical development for curing PC are summarized. Finally, the possibility of targeting S1P metabolism alone or combined with other therapies in the foreseeable future as an alternative option for PC patients is discussed. Research Strategy: PubMed from INSB was used for article research. First, key words "prostate & sphingosine" were used and 144 articles were found. We also realized other combinations of key words as "prostate cancer bone metastasis" and "prostate cancer treatment". We used the most recent reviews to illustrate prostate cancer topic and sphingolipid metabolism overview topic.

Cross-Regulation of the Cellular Redox System, Oxygen, and Sphingolipid Signalling

Redox-active mediators are now appreciated as powerful molecules to regulate cellular dynamics such as viability, proliferation, migration, cell contraction, and relaxation, as well as gene expression under physiological and pathophysiological conditions. These molecules include the various reactive oxygen species (ROS), and the gasotransmitters nitric oxide (NO∙), carbon monoxide (CO), and hydrogen sulfide (H2S). For each of these molecules, direct targets have been identified which transmit the signal from the cellular redox state to a cellular response. Besides these redox mediators, various sphingolipid species have turned out as highly bioactive with strong signalling potential. Recent data suggest that there is a cross-regulation existing between the redox mediators and sphingolipid molecules that have a fundamental impact on a cell’s fate and organ function. This review will summarize the effects of the different redox-active mediators on sphingolipid signalling and metabolism, and the impact of this cross-talk on pathophysiological processes. The relevance of therapeutic approaches will be highlighted.

Sphingolipids and impaired hypoxic stress responses in Huntington disease

Huntington disease (HD) is a debilitating, currently incurable disease. Protein aggregation and metabolic deficits are pathological hallmarks but their link to neurodegeneration and symptoms remains debated. Here, we summarize alterations in the levels of different sphingolipids in an attempt to characterize sphingolipid patterns specific to HD, an additional molecular hallmark of the disease. Based on the crucial role of sphingolipids in maintaining cellular homeostasis, the dynamic regulation of sphingolipids upon insults and their involvement in cellular stress responses, we hypothesize that maladaptations or blunted adaptations, especially following cellular stress due to reduced oxygen supply (hypoxia) contribute to the development of pathology in HD. We review how sphingolipids shape cellular energy metabolism and control proteostasis and suggest how these functions may fail in HD and in combination with additional insults. Finally, we evaluate the potential of improving cellular resilience in HD by conditioning approaches (improving the efficiency of cellular stress responses) and the role of sphingolipids therein. Sphingolipid metabolism is crucial for cellular homeostasis and for adaptations following cellular stress, including hypoxia. Inadequate cellular management of hypoxic stress likely contributes to HD progression, and sphingolipids are potential mediators. Targeting sphingolipids and the hypoxic stress response are novel treatment strategies for HD.

Lipids as Targets for Renal Cell Carcinoma Therapy

Kidney cancer is among the top ten most common cancers to date. Within the kidney, renal cell carcinoma (RCC) is the most common solid lesion occurring. While various risk factors are suspected, including unhealthy lifestyle, age, and ethnicity, genetic mutations seem to be a key risk factor. In particular, mutations in the von Hippel-Lindau gene (Vhl) have attracted a lot of interest since this gene regulates the hypoxia inducible transcription factors HIF-1α and HIF-2α, which in turn drive the transcription of many genes that are important for renal cancer growth and progression, including genes involved in lipid metabolism and signaling. Recent data suggest that HIF-1/2 are themselves regulated by bioactive lipids which make the connection between lipids and renal cancer obvious. This review will summarize the effects and contributions of the different classes of bioactive lipids, including sphingolipids, glycosphingolipids, eicosanoids, free fatty acids, cannabinoids, and cholesterol to renal carcinoma progression. Novel pharmacological strategies interfering with lipid signaling to treat renal cancer will be highlighted.

Phase I study of opaganib, an oral sphingosine kinase 2-specific inhibitor, in relapsed and/or refractory multiple myeloma

Multiple myeloma (MM) remains an incurable disease and there is an unmet medical need for novel therapeutic drugs that do not share similar mechanisms of action with currently available agents. Sphingosine kinase 2 (SK2) is an innovative molecular target for anticancer therapy. We previously reported that treatment with SK2 inhibitor opaganib inhibited myeloma tumor growth in vitro and in vivo in a mouse xenograft model. In the current study, we performed a phase I study of opaganib in patients with relapsed/refractory multiple myeloma (RRMM). Thirteen patients with RRMM previously treated with immunomodulatory agents and proteasome inhibitors were enrolled and treated with single-agent opaganib at three oral dosing regimens (250 mg BID, 500 mg BID, or 750 mg BID, 28 days as a cycle). Safety and maximal tolerated dose (MTD) were determined. Pharmacokinetics, pharmacodynamics, and correlative studies were also performed. Opaganib was well tolerated up to a dose of 750 mg BID. The most common possibly related adverse event (AE) was decreased neutrophil counts. There were no serious AEs considered to be related to opaganib. MTD was determined as at least 750 mg BID. On an intent-to-treat basis, one patient (7.7%) in the 500 mg BID dose cohort showed a very good partial response, and one other patient (7.7%) achieved stable disease for 3 months. SK2 is an innovative molecular target for antimyeloma therapy. The first-in-class SK2 inhibitor opaganib is generally safe for administration to RRMM patients, and has potential therapeutic activity in these patients. Clinicaltrials.gov: NCT02757326.

Therapeutic effect of postoperative adjuvant transcatheter arterial chemoembolization based on the neutrophil-to-lymphocyte ratio

Aim

To evaluate the feasibility of the preoperative neutrophil-to-lymphocyte ratio (NLR) as an index to guide postoperative adjuvant transcatheter arterial chemoembolization (PA-TACE) in patients with liver cancer.

Methods

We recruited a total of 166 patients with liver cancer who underwent surgery alone or surgery plus PA-TACE between January 2013 and June 2017 and compared the 1, 2, and 3-year recurrence-free survival (RFS) and overall survival (OS) between patients with high and low NLRs, surgery and surgery plus PA-TACE groups, and relevant subgroups using the Kaplan-Meier method. We also evaluated the independent factors affecting the prognosis of liver cancer after surgery using a Cox risk ratio model and correlation between NLR levels and high-risk recurrence factors of liver cancer with logistic regression analysis.

Results

The 1, 2, and 3-year RFS rates were all significantly higher in the low-NLR group compared to the high-NLR group (P < 0.05). However, the 1, 2, and 3-year OS rates were similar in the low- and high-NLR groups (P > 0.05). After propensity score matching, the 1, 2, and 3-year RFS and OS rates were significantly better in patients treated with surgery plus PA-TACE compared with surgery alone (P < 0.05). The 1, 2, and 3-year RFS and OS rates were also significantly better in the surgery plus PA-TACE subgroup compared with the surgery-alone subgroup in the high-NLR group (P < 0.05), but there was no significant difference in RFS or OS between the surgery plus PA-TACE and surgery-alone subgroups at 1, 2, and 3 years in the low-NLR group (P > 0.05). Multivariate analysis in the high-NLR group showed that a poorly differentiated or undifferentiated tumor was an independent risk factor for postoperative RFS. Multiple tumors were an independent risk factor for postoperative OS (P < 0.05), while PA-TACE was an independent protective factor for postoperative RFS and OS (P < 0.05). In the low-NLR group, AFP > 400 µg/L was an independent risk factor for postoperative OS (P < 0.05). Multivariate logistic regression indicated that patients with a maximum tumor diameter of >5 cm were at increased risk of having high NLR levels compared to patients with a maximum tumor diameter of <5 cm (P < 0.05).

Conclusion

PA-TACE can improve the prognosis of patients with a high preoperative NLR (≥2.5), but has no obvious benefit in patients with low preoperative NLR (<2.5). This may provide a reference for clinical selection of PA-TACE.

TIDE: adjuvant tislelizumab plus donafenib combined with transarterial chemoembolization for high-risk hepatocellular carcinoma after surgery: protocol for a prospective, single-arm, phase II trial

Background

The high recurrence rate of hepatocellular carcinoma (HCC) after surgery negatively affects the prognosis of patients. There is currently no widely accepted adjuvant therapy strategy for patients with HCC. A clinical study of effective adjuvant therapy is still needed.

Methods

In this prospective, single-arm, phase II clinical trial, an adjuvant regimen of donafenib plus tislelizumab combined with transarterial chemoembolization (TACE) will be used to treat enrolled HCC patients after surgery. Briefly, patients newly diagnosed with HCC by pathological examination who underwent curative resection and had a single tumor more than 5 cm in diameter with microvascular invasion as detected by pathological examination are eligible. The primary endpoint of the study is the recurrence-free survival (RFS) rate at 3 years, and secondary endpoints are the overall survival (OS) rate and the incidence of adverse events (AEs). The planned sample size, 32 patients, was calculated to permit the accumulation of sufficient RFS events in 3 years to achieve 90% power for the RFS primary endpoint.

Discussion

Vascular endothelial growth factor (VEGF) and programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathways regulate the relevant immunosuppressive mechanisms of HCC recurrence. Our trial will evaluate the clinical benefit of adding donafenib plus tislelizumab to TACE in patients with early-stage HCC and a high risk of recurrence.

Clinical trial registration

www.chictr.org.cn, identifier ChiCTR2200063003.

Hypoxia-inducible factor 1-alpha is a driving mechanism linking chronic obstructive pulmonary disease to lung cancer

Patients with chronic obstructive pulmonary disease (COPD), irrespective of their smoking history, are more likely to develop lung cancer than the general population. This is mainly because COPD is characterized by chronic persistent inflammation and hypoxia, which are the risk factors for lung cancer. However, the mechanisms underlying this observation are still unknown. Hypoxia-inducible factor 1-alpha (HIF-1α) plays an important role in the crosstalk that exists between inflammation and hypoxia. Furthermore, HIF-1α is the main regulator of somatic adaptation to hypoxia and is highly expressed in hypoxic environments. In this review, we discuss the molecular aspects of the crosstalk between hypoxia and inflammation, showing that HIF-1α is an important signaling pathway that drives COPD progression to lung cancer. Here, we also provide an overview of HIF-1α and its principal regulatory mechanisms, briefly describe HIF-1α-targeted therapy in lung cancer, and summarize substances that may be used to target HIF-1α at the level of COPD-induced inflammation.

SPHK/HIF-1α Signaling Pathway Has a Critical Role in Chrysin-Induced Anticancer Activity in Hypoxia-Induced PC-3 Cells

Hypoxia, a typical feature of locally advanced solid tumors including prostate cancer, is a critical contributor to tumor progression and causes resistance to therapy. In this study, we investigated the effects of chrysin on tumor progression in hypoxic PC-3 cells. Chrysin exerted a significant inhibitory effect on 3D cell growth under normoxic and hypoxic conditions. It also decreased the hypoxia-induced vasculogenic mimicry and attenuated the expression of HIF-1α and VE-cadherin. Chrysin inhibited HIF-1α accumulation in a concentration- and time-dependent manner in hypoxic PC-3 cells, while also suppressing the expression of HIF-1α by inhibiting SPHK-1 in both CoCl₂ and hypoxic PC-3 cells. At high concentrations of chrysin, there was a greater increase in apoptosis in the hypoxic cells compared to that in normoxic cells, which was accompanied by sub-G1 phase arrest. Chrysin-induced apoptosis inhibited VEGF and Bcl-2 and induced the cleavage of PARP and caspase-3. SPHK-1 knockdown induced apoptosis and inhibited epithelial–mesenchymal transition. Consistent with the in vitro data, 50 mg/kg of chrysin suppressed the tumor growth of PC-3 xenografts by 80.4% compared to that in the untreated control group. The immunohistochemistry of tumor tissues revealed decreased Ki-67, HIF-1α, and VEGF expression in the chrysin-treated group compared to an untreated control. Western blotting data for tumor tissues showed that chrysin treatment decreased SPHK-1, HIF-1α, and PARP expression while inducing caspase-3 cleavage. Overall, our findings suggest that chrysin exerts anti-tumor activity by inhibiting SPHK-1/HIF-1α signaling and thus represents a potent chemotherapeutic agent for hypoxia, which promotes cancer progression and is related to poor prognoses in prostate cancer patients.

Sphk1 and Sphk2 Differentially Regulate Erythropoietin Synthesis in Mouse Renal Interstitial Fibroblast-like Cells

Erythropoietin (Epo) is a crucial hormone regulating red blood cell number and consequently the hematocrit. Epo is mainly produced in the kidney by interstitial fibroblast-like cells. Previously, we have shown that in cultures of the immortalized mouse renal fibroblast-like cell line FAIK F3-5, sphingosine 1-phosphate (S1P), by activating S1P₁ and S1P₃ receptors, can stabilize hypoxia-inducible factor (HIF)-2α and upregulate Epo mRNA and protein synthesis. In this study, we have addressed the role of intracellular iS1P derived from sphingosine kinases (Sphk) 1 and 2 on Epo synthesis in F3-5 cells and in mouse primary cultures of renal fibroblasts. We show that stable knockdown of Sphk2 in F3-5 cells increases HIF-2α protein and Epo mRNA and protein levels, while Sphk1 knockdown leads to a reduction of hypoxia-stimulated HIF-2α and Epo protein. A similar effect was obtained using primary cultures of renal fibroblasts isolated from wildtype mice, Sphk1−/−, or Sphk2−/− mice. Furthermore, selective Sphk2 inhibitors mimicked the effect of genetic Sphk2 depletion and also upregulated HIF-2α and Epo protein levels. The combined blockade of Sphk1 and Sphk2, using Sphk2−/− renal fibroblasts treated with the Sphk1 inhibitor PF543, resulted in reduced HIF-2α and Epo compared to the untreated Sphk2−/− cells. Exogenous sphingosine (Sph) enhanced HIF-2α and Epo, and this was abolished by the combined treatment with the selective S1P₁ and S1P₃ antagonists NIBR-0213 and TY52156, suggesting that Sph was taken up by cells and converted to iS1P and exported to then act in an autocrine manner through S1P₁ and S1P₃. The upregulation of HIF-2α and Epo synthesis by Sphk2 knockdown was confirmed in the human hepatoma cell line Hep3B, which is well-established to upregulate Epo production under hypoxia. In summary, these data show that sphingolipids have diverse effects on Epo synthesis. While accumulation of intracellular Sph reduces Epo synthesis, iS1P will be exported to act through S1P₁₊₃ to enhance Epo synthesis. Furthermore, these data suggest that selective inhibition of Sphk2 is an attractive new option to enhance Epo synthesis and thereby to reduce anemia development in chronic kidney disease.

The Specific Role of Reactive Astrocytes in Stroke

Astrocytes are essential in maintaining normal brain functions such as blood brain barrier (BBB) homeostasis and synapse formation as the most abundant cell type in the central nervous system (CNS). After the stroke, astrocytes are known as reactive astrocytes (RAs) because they are stimulated by various damage-associated molecular patterns (DAMPs) and cytokines, resulting in significant changes in their reactivity, gene expression, and functional characteristics. RAs perform multiple functions after stroke. The inflammatory response of RAs may aggravate neuro-inflammation and release toxic factors to exert neurological damage. However, RAs also reduce excitotoxicity and release neurotrophies to promote neuroprotection. Furthermore, RAs contribute to angiogenesis and axonal remodeling to promote neurological recovery. Therefore, RAs' biphasic roles and mechanisms make them an effective target for functional recovery after the stroke. In this review, we summarized the dynamic functional changes and internal molecular mechanisms of RAs, as well as their therapeutic potential and strategies, in order to comprehensively understand the role of RAs in the outcome of stroke disease and provide a new direction for the clinical treatment of stroke.

ALKBH5 Regulates SPHK1-Dependent Endothelial Cell Angiogenesis Following Ischemic Stress

Background

Endothelial cells dysfunction has been reported in many heart diseases including acute myocardial infarction, and atherosclerosis. The molecular mechanism for endothelial dysfunction in the heart is still not clearly understood. We aimed to study the role of m⁶A RNA demethylase alkB homolog 5 (ALKBH5) in ECs angiogenesis during ischemic injury.

Methods and Results

ECs were treated with ischemic insults (lipopolysaccharide and 1% hypoxia) to determine the role of ALKBH5 in ECs angiogenesis. siRNA mediated ALKBH5 gene silencing was used for examining the loss of function. In this study, we report that ALKBH5 levels are upregulated following ischemia and are associated with maintaining ischemia-induced ECs angiogenesis. To decipher the mechanism of action, we found that ALKBH5 is required to maintain eNOS phosphorylation and SPHK1 protein levels. ALKBH5 silencing alone or with ischemic stress significantly increased SPHK1 m⁶A mRNA methylation. In contrast, METTL3 (RNA methyltransferase) overexpression resulted in the reduced expression of SPHK1.

Conclusion

We reported that ALKBH5 helps in the maintenance of angiogenesis in endothelial cells following acute ischemic stress via reduced SPHK1 m⁶A methylation and downstream eNOS-AKT signaling.

Sphingosine Kinase-1 Is Overexpressed and Correlates with Hypoxia in Osteosarcoma: Relationship with Clinicopathological Parameters

The Sphingosine kinase-1/Sphingosine 1-Phosphate (SphK1/S1P) signaling pathway is overexpressed in various cancers, and is instrumental for the adaptation to hypoxia in a number of solid tumor models, but no data are available in osteosarcoma. Here we report that SphK1 and the S1P₁ receptor are involved in HIF-1α accumulation in hypoxic osteosarcoma cells. FTY720 (Fingolimod), which targets SphK1 and S1P_1, prevented HIF-1α accumulation, and also inhibited cell proliferation in both normoxia and hypoxia unlike conventional chemotherapy. In human biopsies, a significant increase of SphK1 activity was observed in cancer compared with normal bones. In all sets of TMA samples (130 cases of osteosarcoma), immunohistochemical analysis showed the hypoxic marker GLUT-1, SphK1 and S1P₁ were expressed in tumors. SphK1 correlated with the GLUT-1 suggesting that SphK1 is overexpressed and correlates with intratumoral hypoxia. No correlation was found between GLUT-1 or SphK1 and response to chemotherapy, but a statistical difference was found with increased S1P₁ expression in patients with poor response in long bone osteosarcomas. Importantly, multivariate analyses showed that GLUT-1 was associated with an increased risk of death in flat bone, whereas SphK1 and S1P₁ were associated with an increased risk of death in long bones.

Melatonin and Prostate Cancer: Anti-tumor Roles and Therapeutic Application

Melatonin is an endogenous indoleamine that has been shown to inhibit tumor growth in laboratory models of prostate cancer. Prostate cancer risk has additionally been associated with exogenous factors that interfere with normal pineal secretory activity, including aging, poor sleep, and artificial light at night. Therefore, we aim to expand on the important epidemiological evidence, and to review how melatonin can impede prostate cancer. More specifically, we describe the currently known mechanisms of melatonin-mediated oncostasis in prostate cancer, including those that relate to the indolamine's ability to modulate metabolic activity, cell cycle progression and proliferation, androgen signaling, angiogenesis, metastasis, immunity and oxidative cell status, apoptosis, genomic stability, neuroendocrine differentiation, and the circadian rhythm. The outlined evidence underscores the need for clinical trials to determine the efficacy of supplemental, adjunct, and adjuvant melatonin therapy for the prevention and treatment of prostate cancer.

Meta-Analysis of Postoperative Adjuvant Hepatic Artery Infusion Chemotherapy Versus Surgical Resection Alone for Hepatocellular Carcinoma

BACKGROUND

To systematically identify the long-term efficacy of postoperative adjuvant hepatic artery infusion chemotherapy (HAIC) for patients with hepatocellular carcinoma (HCC).

METHODS

PubMed, MedLine, Embase, the Cochrane Library, and Web of Science were searched to collect the eligible studies up to March 31, 2021, that compared the surgical resection (SR) versus SR+HAIC for HCC patients. The endpoints were overall survival (OS) rates and disease-free survival (DFS) rates, and the effect size was determined by hazard ratio (HR) with 95% CI.

RESULTS

A total of 12 studies (two randomized controlled trials (RCTs) and 10 non-RCTs) including 1,333 patients were eligible for this meta-analysis. The pooled results showed that OS and DFS rates in the SR+HAIC group were both better than those in the SR alone group (HR = 0.56, 95% CI = 0.41-0.77, p < 0.001; HR = 0.66, 95% CI = 0.55-0.78, p < 0.001, respectively). Furthermore, the subgroup analysis showed that patients would benefit from SR+HAIC regardless of chemotherapy regimens and courses (all p < 0.05), and patients with microvascular or macrovascular invasion would also benefit more from SR+HAIC in terms of OS and DFS (all p < 0.05).

CONCLUSION

Postoperative adjuvant HAIC could improve the long-term prognosis of HCC patients, especially for those with microvascular or macrovascular invasion, regardless of chemotherapy regimens and courses, but it deserves further validation.

Anti-Cancer Activity of Phytochemicals Targeting Hypoxia-Inducible Factor-1 Alpha

Hypoxia-inducible factor-1 alpha (HIF-1α) is overexpressed in cancer, leading to a poor prognosis in patients. Diverse cellular factors are able to regulate HIF-1α expression in hypoxia and even in non-hypoxic conditions, affecting its progression and malignant characteristics by regulating the expression of the HIF-1α target genes that are involved in cell survival, angiogenesis, metabolism, therapeutic resistance, et cetera. Numerous studies have exhibited the anti-cancer effect of HIF-1α inhibition itself and the augmentation of anti-cancer treatment efficacy by interfering with HIF-1α-mediated signaling. The anti-cancer effect of plant-derived phytochemicals has been evaluated, and they have been found to possess significant therapeutic potentials against numerous cancer types. A better understanding of phytochemicals is indispensable for establishing advanced strategies for cancer therapy. This article reviews the anti-cancer effect of phytochemicals in connection with HIF-1α regulation.

S1P Stimulates Erythropoietin Production in Mouse Renal Interstitial Fibroblasts by S1P1 and S1P3 Receptor Activation and HIF-2α Stabilization

Erythropoietin (Epo) is the critical hormone for erythropoiesis. In adults, Epo is mainly produced by a subset of interstitial fibroblasts in the kidney, with minor amounts being produced in the liver and the brain. In this study, we used the immortalized renal interstitial fibroblast cell line FAIK F3-5 to investigate the ability of the bioactive sphingolipid sphingosine 1-phosphate (S1P) to stimulate Epo production and to reveal the mechanism involved. Stimulation of cells with exogenous S1P under normoxic conditions (21% O₂) led to a dose-dependent increase in Epo mRNA and protein levels and subsequent release of Epo into the medium. S1P also enhanced the stabilization of HIF-2α, a key transcription factor for Epo expression. S1P-stimulated Epo mRNA and protein expression was abolished by HIF-2α mRNA knockdown or by the HIF-2 inhibitor compound 2. Furthermore, the approved S1P receptor modulator FTY720, and its active form FTY720-phosphate, both exerted a similar effect on Epo expression as S1P. The effect of S1P on Epo was antagonized by the selective S1P₁ and S1P₃ antagonists NIBR-0213 and TY-52156, but not by the S1P₂ antagonist JTE-013. Moreover, inhibitors of the classical MAPK/ERK, the p38-MAPK, and inhibitors of protein kinase (PK) C and D all blocked the effect of S1P on Epo expression. Finally, the S1P and FTY720 effects were recapitulated in the Epo-producing human neuroblastoma cell line Kelly, suggesting that S1P receptor-dependent Epo synthesis is of general relevance and not species-specific. In summary, these data suggest that, in renal interstitial fibroblasts, which are the primary source of plasma Epo, S1P_{1 and 3} receptor activation upregulates Epo under normoxic conditions. This may have a therapeutic impact on disease situations such as chronic kidney disease, where Epo production is impaired, causing anemia, but it may also have therapeutic value as Epo can mediate additional tissue-protective effects in various organs.

Macrophage Motility in Wound Healing Is Regulated by HIF-1α via S1P Signaling

Accumulating evidence indicates that the molecular pathways mediating wound healing induce cell migration and localization of cytokines to sites of injury. Macrophages are immune cells that sense and actively respond to disturbances in tissue homeostasis by initiating, and subsequently resolving, inflammation. Hypoxic conditions generated at a wound site also strongly recruit macrophages and affect their function. Hypoxia inducible factor (HIF)-1α is a transcription factor that contributes to both glycolysis and the induction of inflammatory genes, while also being critical for macrophage activation. For the latter, HIF-1α regulates sphingosine 1-phosphate (S1P) to affect the migration, activation, differentiation, and polarization of macrophages. Recently, S1P and HIF-1α have received much attention, and various studies have been performed to investigate their roles in initiating and resolving inflammation via macrophages. It is hypothesized that the HIF-1α/S1P/S1P receptor axis is an important determinant of macrophage function under inflammatory conditions and during disease pathogenesis. Therefore, in this review, biological regulation of monocytes/macrophages in response to circulating HIF-1α is summarized, including signaling by S1P/S1P receptors, which have essential roles in wound healing.

A prospective trial of abiraterone acetate plus prednisone in Black and White men with metastatic castrate-resistant prostate cancer

BACKGROUND

Retrospective analyses of randomized trials suggest that Black men with metastatic castration-resistant prostate cancer (mCRPC) have longer survival than White men. The authors conducted a prospective study of abiraterone acetate plus prednisone to explore outcomes by race.

METHODS

This race-stratified, multicenter study estimated radiographic progression-free survival (rPFS) in Black and White men with mCRPC. Secondary end points included prostate-specific antigen (PSA) kinetics, overall survival (OS), and safety. Exploratory analysis included genome-wide genotyping to identify single nucleotide polymorphisms associated with progression in a model incorporating genetic ancestry. One hundred patients self-identified as White (n = 50) or Black (n = 50) were enrolled. Eligibility criteria were modified to facilitate the enrollment of individual Black patients.

RESULTS

The median rPFS for Black and White patients was 16.6 and 16.8 months, respectively; their times to PSA progression (TTP) were 16.6 and 11.5 months, respectively; and their OS was 35.9 and 35.7 months, respectively. Estimated rates of PSA decline by ≥50% in Black and White patients were 74% and 66%, respectively; and PSA declines to <0.2 ng/mL were 26% and 10%, respectively. Rates of grade 3 and 4 hypertension, hypokalemia, and hyperglycemia were higher in Black men.

CONCLUSIONS

Multicenter prospective studies by race are feasible in men with mCRPC but require less restrictive eligibility. Despite higher comorbidity rates, Black patients demonstrated rPFS and OS similar to those of White patients and trended toward greater TTP and PSA declines, consistent with retrospective reports. Importantly, Black men may have higher side-effect rates than White men. This exploratory genome-wide analysis of TTP identified a possible candidate marker of ancestry-dependent treatment outcomes.

3D Collagen Hydrogel Promotes In Vitro Langerhans Islets Vascularization through ad-MVFs Angiogenic Activity

Adipose derived microvascular fragments (ad-MVFs) consist of effective vascularization units able to reassemble into efficient microvascular networks. Because of their content in stem cells and related angiogenic activity, ad-MVFs represent an interesting tool for applications in regenerative medicine. Here we show that gentle dissociation of rat adipose tissue provides a mixture of ad-MVFs with a length distribution ranging from 33–955 μm that are able to maintain their original morphology. The isolated units of ad-MVFs that resulted were able to activate transcriptional switching toward angiogenesis, forming tubes, branches, and entire capillary networks when cultured in 3D collagen type-I hydrogel. The proper involvement of metalloproteases (MMP2/MMP9) and serine proteases in basal lamina and extracellular matrix ECM degradation during the angiogenesis were concurrently assessed by the evaluation of alpha-smooth muscle actin (αSMA) expression. These results suggest that collagen type-I hydrogel provides an adequate 3D environment supporting the activation of the vascularization process. As a proof of concept, we exploited 3D collagen hydrogel for the setting of ad-MVF–islet of Langerhans coculture to improve the islets vascularization. Our results suggest potential employment of the proposed in vitro system for regenerative medicine applications, such as the improving of the islet of Langerhans engraftment before transplantation.

Cancer Cell Metabolism in Hypoxia: Role of HIF-1 as Key Regulator and Therapeutic Target

In order to meet the high energy demand, a metabolic reprogramming occurs in cancer cells. Its role is crucial in promoting tumor survival. Among the substrates in demand, oxygen is fundamental for bioenergetics. Nevertheless, tumor microenvironment is frequently characterized by low-oxygen conditions. Hypoxia-inducible factor 1 (HIF-1) is a pivotal modulator of the metabolic reprogramming which takes place in hypoxic cancer cells. In the hub of cellular bioenergetics, mitochondria are key players in regulating cellular energy. Therefore, a close crosstalk between mitochondria and HIF-1 underlies the metabolic and functional changes of cancer cells. Noteworthy, HIF-1 represents a promising target for novel cancer therapeutics. In this review, we summarize the molecular mechanisms underlying the interplay between HIF-1 and energetic metabolism, with a focus on mitochondria, of hypoxic cancer cells.

Cellular and Molecular Mechanisms of Pristimerin in Cancer Therapy: Recent Advances

Seeking an efficient and safe approach to eliminate tumors is a common goal of medical fields. Over these years, traditional Chinese medicine has attracted growing attention in cancer treatment due to its long history. Pristimerin is a naturally occurring quinone methide triterpenoid used in traditional Chinese medicine to treat various cancers. Recent studies have identified alterations in cellular events and molecular signaling targets of cancer cells under pristimerin treatment. Pristimerin induces cell cycle arrest, apoptosis, and autophagy to exhibit anti-proliferation effects against tumors. Pristimerin also inhibits the invasion, migration, and metastasis of tumor cells via affecting cell adhesion, cytoskeleton, epithelial-mesenchymal transition, cancer stem cells, and angiogenesis. Molecular factors and pathways are associated with the anti-cancer activities of pristimerin. Furthermore, pristimerin reverses multidrug resistance of cancer cells and exerts synergizing effects with other chemotherapeutic drugs. This review aims to discuss the anti-cancer potentials of pristimerin, emphasizing multi-targeted biological and molecular regulations in cancers. Further investigations and clinical trials are warranted to understand the advantages and disadvantages of pristimerin treatment much better.

HIF-1α controls palatal wound healing by regulating macrophage motility via S1P/S1P1 signaling axis

OBJECTIVES

To investigate the role of hypoxia-inducible factor 1α (HIF-1α) signaling, the expression profile of M1 and M2 macrophages, and the role of the sphingosine 1-phosphate (S1P)/S1P receptor system in palatal wound healing of heterozygous HIF-1α-deficient (HIF-1α HET) mice.

MATERIALS AND METHODS

HIF-1α HET and wild-type (WT) littermates underwent palatal tissue excision at the mid-hard palate. Histological analysis, immunostaining, real-time PCR, Western blotting (WB), and cellular migration assays were performed to analyze wound closure and macrophage infiltration.

RESULTS

DMOG pretreatment showed an acceleration of palatal wound closure in WT mice. In contrast, the delayed palatal wound closure was observed in HIF-1α HET mice with diminished production of Col1a1, MCP-1, and MIP-1α, compared with WT mice. Decreased infiltration of M1 macrophage (F4/80⁺ TNF-α⁺ , F4/80⁺ iNOS⁺ ) and M2 macrophage (F4/80⁺ Arginase-1⁺ , F4/80⁺ CD163⁺ ) was observed. The numbers of F4/80⁺ S1P₁ ⁺ macrophages of HIF-1α HET wounded tissues were significantly lower compared with WT tissues. S1P treatment of bone marrow macrophages (BMMs) significantly upregulated expression of S1P₁ in WT mice compared with HIF-1α HET. Phosphorylation of MAPK rapidly decreased in BMMs of HIF-1α HET mice than in BMMs of WT mice by S1P stimulation. Moreover, S1P enhanced HIF-1α expression via S1P₁ receptors to affect macrophage migration.

CONCLUSIONS

HIF-1α deficiency aggravates M1 and M2 macrophage infiltration and controls macrophage motility via S1P/S1P₁ signaling. These results suggest that HIF-1α signaling may contribute to the regulation of palatal wound healing.

Characterization of human bone marrow niches with metabolome and transcriptome profiling

Bone marrow (BM) niches are special microenvironments that work in harmony with each other for the regulation and maintenance of hematopoiesis. Niche investigations have thus far been limited to various model organisms and animal studies; therefore, little is known about different niches in healthy humans. In this study, a special harvesting method for the collection of BM from two different anatomical regions in the iliac crest of humans was used to investigate the presence of different niches in BM. Additionally, metabolomic and transcriptomic profiles were compiled using comparative 'omics' technologies, and the main cellular pathways and corresponding transcripts and metabolites were identified. As a result, we found that the energy metabolism between the regions was different. This study provides basic broad data for regenerative medicine in terms of the design of the appropriate microenvironment for in vitro hematopoietic niche modeling, and identifies the normal reference values that can be compared in hematological disease.

Evaluation of the Therapeutic Effect of Adjuvant Transcatheter Arterial Chemoembolization Based on Ki67 After Hepatocellular Carcinoma Surgery

Background and aims

This study aimed to determine the relationship between Ki67 expression and the efficacy of postoperative adjuvant transcatheter arterial chemoembolization (PA-TACE) in patients with hepatocellular carcinoma.

Methods

The Kaplan-Meier method was used to analyze the recurrence-free survival (RFS) and overall survival (OS) rates between the sub-groups in the ki67 low expression group and the ki67 high expression group and analyze the relationship between the expression of Ki67 and the efficacy of TACE.

Results

After PSM, there was no significant difference in the RFS and OS between the surgery + TACE and surgery subgroups after 1, 2, or 3 years (RFS: 63.9%, 55.6%, and 42.9% vs. 83.3%, 63.9%, and 55.6%, respectively, P = 0.279; OS: 91.7%, 83.3%, and 74.3% vs. 91.7%, 88.9%, and 71.4%, respectively, P = 0.890) in the Ki67 low-expression group. The RFS and OS were higher in the surgery + TACE subgroup than the surgery subgroup after 1, 2, and 3 years (RFS: 80.0%, 77.5%, and 69.2% vs. 53.5%, 39.5%, and 32.6%, respectively, P<0.001; OS: 97.5%, 85.0%, and 79.5% vs. 79.1%, 48.8%, and 42.9%, respectively, P = 0.001) in the Ki67 high expression group. The RFS was higher in the Ki67 high-expression subgroup than the low-expression subgroup after 1, 2, and 3 years, and OS had no significant difference (RFS: 80.0%, 79.5%, and 69.2% vs. 67.4%, 56.5%, and 46.7%, respectively, P = 0.035; OS: 97.5%, 85.0%, and 79.5% vs. 93.5%, 82.6%, and 75.6%, respectively, P = 0.665) in the surgery + TACE group.

Conclusions

For patients with hepatocellular carcinoma and high expression of Ki67 (Ki67≥20%), adjuvant hepatic artery chemoembolization after radical liver tumor resection effectively reduced the probability of tumor recurrence after surgery and prolonged the OS of patients. High Ki67 expression during the post-operative follow-up evaluation of hepatocellular carcinoma patients is an indicator for adjuvant TACE therapy.

Oxidative stress increases 1-deoxysphingolipid levels in chronic kidney disease

Chronic kidney disease (CKD) leads to deep changes in lipid metabolism and obvious dyslipidemia. The dysregulation of lipid metabolism in turn results in CKD progression and the complications of cardiovascular diseases. To obtain a profound insight into the associated dyslipidemia in CKD, we performed lipidomic analysis to measure lipid metabolites in the serum from a rat 5/6 nephrectomy (5/6 Nx) model of CKD as well as in the serum from CKD patients. HK-2 cells were also used to examine oxidative stress-induced sphingolipid changes. Totally 182 lipid species were identified in 5/6 Nx rats. We found glycerolipids, total free fatty acids, and sphingolipids levels were significantly upregulated in 5/6 Nx rats. The atypical sphingolipids, 1-deoxysphingolipids, were significantly altered in both CKD animals and human CKD patients. The levels of 1-deoxysphingolipids directly relevant to the level of oxidative stress in vivo and in vitro. These results demonstrate that 1-deoxysphingolipid levels are increased in CKD and this increase directly correlates with increased kidney oxidative stress.

Sphingolipids as multifaceted mediators in ovarian cancer

Ovarian cancer is the most lethal gynaecological malignancy. It is commonly diagnosed at advanced stage when it has metastasised to the abdominal cavity and treatment becomes very challenging. While current standard therapy involving debulking surgery and platinum + taxane-based chemotherapy is associated with high response rates initially, the large majority of patients relapse and ultimately succumb to chemotherapy-resistant disease. In order to improve survival novel strategies for early detection and therapeutics against treatment-refractory disease are urgently needed. A promising new target against ovarian cancer is the sphingolipid pathway which is commonly hijacked in cancer to support cell proliferation and survival and has been shown to promote chemoresistance and metastasis in a wide range of malignant neoplasms. In particular, the sphingosine kinase 1-sphingosine 1-phosphate receptor 1 axis has been shown to be altered in ovarian cancer in multiple ways and therefore represents an attractive therapeutic target. Here we review the roles of sphingolipids in ovarian cancer progression, metastasis and chemoresistance, highlighting novel strategies to target this pathway that represent potential avenues to improve patient survival.

Sphingosine 1-phosphate in sepsis and beyond: Its role in disease tolerance and host defense and the impact of carrier molecules

Sphingosine 1-phosphate (S1P) is an important immune modulator responsible for physiological cellular responses like lymphocyte development and function, positioning and emigration of T and B cells and cytokine secretion. Recent reports indicate that S1P does not only regulate immunity, but can also protect the function of organs by inducing disease tolerance. S1P also influences the replication of certain pathogens, and sphingolipids are also involved in pathogen recognition and killing. Certain carrier molecules for S1P like serum albumin and high density lipoproteins contribute to the regulation of S1P effects. They are able to associate with S1P and modulate its signaling properties. Similar to S1P, both carrier molecules are also decreased in sepsis patients and likely contribute to sepsis pathology and severity. In this review, we will introduce the concept of disease tolerance and the involvement of S1P. We will also discuss the contribution of S1P and its precursor sphingosine to host defense mechanisms against pathogens. Finally, we will summarize current data demonstrating the influence of carrier molecules for differential S1P signaling. The presented data may lead to new strategies for the prevention and containment of sepsis.

Sphingosine kinase 1 contributes to doxorubicin resistance and glycolysis in osteosarcoma

Osteosarcoma (OS) is one of the most common and aggressive malignancies in children and adolescents worldwide. Sphingosine kinase 1 (SphK1) has recently been reported to serve a role in OS progression. The present study aimed to investigate the role of SphK1 in the development of chemoresistance and glycolysis in OS cell lines. SphK1 expression levels in OS cell lines (U2OS, MG63 and SaoS2) were analyzed using western blotting and reverse transcription-quantitative PCR (RT-qPCR). A cell survival assay was conducted to determine doxorubicin-resistance in OS cells, and glycolysis was also evaluated. SphK1 expression was increased in the U2OS and SaoS2 cell lines, and both cell lines were more resistant to doxorubicin when compared with the MG63 cell line. SphK1 knockdown or overexpression altered doxorubicin resistance and the viability of OS cell lines. In addition, hypoxia inducible factor-1α (HIF-1α) expression was positively associated with SphK1 expression, and partly mediated SphK1-induced effects on doxorubicin resistance and glycolysis. The present study suggested that SphK1 participated in the development of doxorubicin resistance and contributed to glycolysis in OS cells by regulating HIF-1α expression. However, further studies investigating the application of SphK1 associated therapies for patients with OS are required.

A systematic review and meta-analysis of adjuvant transarterial chemoembolization after curative resection for patients with hepatocellular carcinoma

BACKGROUND

The aim of this study was to systematically evaluate and determine those patients with hepatocellular carcinoma (HCC) that would benefit from the administration of postoperative adjuvant transarterial chemoembolization (PA-TACE).

METHODS

PubMed, Embase and Cochrane Library were searched for randomized controlled trials (RCTs) and observational studies up to July 30, 2019. The outcome of Overall survival (OS) and disease-free survival (DFS) were extracted and converted to hazard ratios (HRs) with 95% confidence intervals (95%CIs).

RESULTS

A total of 40 studies (10 RCTs and 30 non-RCTs) involving 11,165 patients were included. Overall, PA-TACE was associated with an increased OS [HR, 0.71 (95% CI, 0.65-0.77); P < 0.001] and DFS [HR, 0.73 (95% CI, 0.66-0.80); P < 0.001]. Subgroup analysis in patients with microvascular invasion (MVI), tumor diameter >5 cm or multinodular tumors demonstrated that PA-TACE improved OS and DFS. In patients without MVI, PA-TACE showed no improvement in OS [HR, 1.14 (95% CI, 0.85-1.53); P = 0.370], and resulted in worse DFS than curative resection alone [HR, 1.20 (95% CI, 1.03-1.39); P = 0.002].

CONCLUSION

This meta-analysis indicated that PA-TACE was beneficial in patients with HCC who were at high risk of postoperative recurrence including tumor diameter >5 cm, multinodular tumors and MVI-positive. In patients with tumor diameter ≤5 cm, single tumor or MVI-negative. PA-TACE does not appear to improve outcomes and may potentially promote postoperative recurrence in certain patients.

Relationship between Sphk1/S1P and microRNAs in human cancers

Sphingosine kinases type 1 (SphK1) is a key enzyme in the phosphorylation of sphingosine to sphingosine 1-phosphate (S1P). Different abnormalities in SphK1 functions may correspond with poor prognosis in various cancers. Additionally, upregulated SphK1/S1P could promote cancer cell proliferation, angiogenesis, mobility, invasion, and metastasis. MicroRNAs as conserved small noncoding RNAs play major roles in cancer initiation, progression, metastasis, etc. Their posttranscriptionally mechanisms could affect the development of cancer growth or tumorigenesis suppression. The growing number of studies has described that various microRNAs can be regulated by SphK1, and its expression level can also be regulated by microRNAs. In this review, the relationship of SphK1 and microRNA functions and their interaction in human malignancies have been discussed. Based on them novel treatment strategies can be introduced.

The therapeutic value of SC66 in human renal cell carcinoma cells

The PI3K-AKT-mTOR cascade is required for renal cell carcinoma (RCC) progression. SC66 is novel AKT inhibitor. We found that SC66 inhibited viability, proliferation, migration and invasion of RCC cell lines (786-O and A498) and patient-derived primary RCC cells. Although SC66blocked AKT-mTORC1/2 activation in RCC cells, it remained cytotoxic in AKT-inhibited/-silenced RCC cells. In RCC cells, SC66 cytotoxicity appears to occur via reactive oxygen species (ROS) production, sphingosine kinase 1inhibition, ceramide accumulation and JNK activation, independent of AKT inhibition. The ROS scavenger N-acetylcysteine, the JNK inhibitor (JNKi) and the anti-ceramide sphingolipid sphingosine-1-phosphate all attenuated SC66-induced cytotoxicity in 786-O cells. In vivo, oral administration of SC66 potently inhibited subcutaneous 786-O xenograft growth in SCID mice. AKT-mTOR inhibition, SphK1 inhibition, ceramide accumulation and JNK activation were detected in SC66-treated 786-O xenograft tumors, indicating that SC66 inhibits RCC cell progression through AKT-dependent and AKT-independent mechanisms.

Preclinical validation of Alpha-Enolase (ENO1) as a novel immunometabolic target in multiple myeloma

Bone marrow plasmacytoid dendritic cells (pDCs) in patients with multiple myeloma (MM) promote tumor growth, survival, drug resistance, and immune suppression. Understanding the molecular signaling crosstalk among the tumor cells, pDCs and immune cells will identify novel therapeutic approaches to enhance anti-MM immunity. Using oligonucleotide arrays, we found that pDC-MM interactions induce metabolic enzyme Alpha-Enolase (ENO1) in both pDCs and MM cells. Analysis of MM patient gene expression profiling database showed that ENO1 expression inversely correlates with overall survival. Protein expression analysis showed that ENO1 is expressed in pDC and MM cells; and importantly, that pDC-MM coculture further increases ENO1 expression in both MM cells and pDCs. Using our coculture models of patient autologous pDC-T-NK-MM cells, we examined whether targeting ENO1 can enhance anti-MM immunity. Biochemical inhibition of ENO1 with ENO1 inhibitor (ENO1i) activates pDCs, as well as increases pDC-induced MM-specific CD8⁺ CTL and NK cell activity against autologous tumor cells. Combination of ENO1i and anti-PD-L1 Ab or HDAC6i ACY-241 enhances autologous MM-specific CD8⁺ CTL activity. Our preclinical data therefore provide the basis for novel immune-based therapeutic approaches targeting ENO1, alone or in combination with anti-PD-L1 Ab or ACY241, to restore anti-MM immunity, enhance MM cytotoxicity, and improve patient outcome.

Sphingosine-1-Phosphate in the Tumor Microenvironment: A Signaling Hub Regulating Cancer Hallmarks

As a key hub of malignant properties, the cancer microenvironment plays a crucial role intimately connected to tumor properties. Accumulating evidence supports that the lysophospholipid sphingosine-1-phosphate acts as a key signal in the cancer extracellular milieu. In this review, we have a particular focus on glioblastoma, representative of a highly aggressive and deleterious neoplasm in humans. First, we highlight recent advances and emerging concepts for how tumor cells and different recruited normal cells contribute to the sphingosine-1-phosphate enrichment in the cancer microenvironment. Then, we describe and discuss how sphingosine-1-phosphate signaling contributes to favor cancer hallmarks including enhancement of proliferation, stemness, invasion, death resistance, angiogenesis, immune evasion and, possibly, aberrant metabolism. We also discuss the potential of how sphingosine-1-phosphate control mechanisms are coordinated across distinct cancer microenvironments. Further progress in understanding the role of S1P signaling in cancer will depend crucially on increasing knowledge of its participation in the tumor microenvironment.

S1P Signaling in the Tumor Microenvironment

Sphingosine-1-phosphate (S1P), together with other phosphosphingolipids, has been found to regulate complex cellular function in the tumor microenvironment (TME) where it acts as a signaling molecule that participates in cell-cell communication. S1P, through intracellular and extracellular signaling, was found to promote tumor growth, angiogenesis, chemoresistance, and metastasis; it also regulates anticancer immune response, modulates inflammation, and promotes angiogenesis. Interestingly, cancer cells are capable of releasing S1P and thus modifying the behavior of the TME components in a way that contributes to tumor growth and progression. Therefore, S1P is considered an important therapeutic target, and several anticancer therapies targeting S1P signaling are being developed and tested in clinics.

Sphingolipids in Obesity and Correlated Co-Morbidities: The Contribution of Gender, Age and Environment

This paper reviews our present knowledge on the contribution of ceramide (Cer), sphingomyelin (SM), dihydroceramide (DhCer) and sphingosine-1-phosphate (S1P) in obesity and related co-morbidities. Specifically, in this paper, we address the role of acyl chain composition in bodily fluids for monitoring obesity in males and females, in aging persons and in situations of environmental hypoxia adaptation. After a brief introduction on sphingolipid synthesis and compartmentalization, the node of detection methods has been critically revised as the node of the use of animal models. The latter do not recapitulate the human condition, making it difficult to compare levels of sphingolipids found in animal tissues and human bodily fluids, and thus, to find definitive conclusions. In human subjects, the search for putative biomarkers has to be performed on easily accessible material, such as serum. The serum “sphingolipidome” profile indicates that attention should be focused on specific acyl chains associated with obesity, per se, since total Cer and SM levels coupled with dyslipidemia and vitamin D deficiency can be confounding factors. Furthermore, exposure to hypoxia indicates a relationship between dyslipidemia, obesity, oxygen level and aerobic/anaerobic metabolism, thus, opening new research avenues in the role of sphingolipids.

mTOR signalling and cellular metabolism are mutual determinants in cancer

Oncogenic signalling and metabolic alterations are interrelated in cancer cells. mTOR, which is frequently activated in cancer, controls cell growth and metabolism. mTOR signalling regulates amino acid, glucose, nucleotide, fatty acid and lipid metabolism. Conversely, metabolic inputs, such as amino acids, activate mTOR. In this Review, we discuss how mTOR signalling rewires cancer cell metabolism and delineate how changes in metabolism, in turn, sustain mTOR signalling and tumorigenicity. Several drugs are being developed to perturb cancer cell metabolism. However, their efficacy as stand-alone therapies, similar to mTOR inhibitors, is limited. Here, we discuss how the interdependence of mTOR signalling and metabolism can be exploited for cancer therapy.

The sphingosine kinase-1/sphingosine-1-phosphate axis in cancer: Potential target for anticancer therapy

Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate (S1P), play many important roles in cellular activities. Ceramide and sphingosine inhibit cell proliferation and induce cell apoptosis while S1P has the opposite effect. Maintaining a metabolic balance of sphingolipids is essential for growth and development of cells. Sphingosine kinase (SPHK) is an important regulator for keeping this balance. It controls the level of S1P and plays important roles in proliferation, migration, and invasion of cancer cells and tumor angiogenesis. There are two isoenzymes of sphingosine kinase, SPHK1 and SPHK2. SPHK1 is ubiquitously expressed in most cancers where it promotes survival and proliferation, while SPHK2 is restricted to only certain tissues and its functions are not well characterized. SPHK1 is currently considered as a novel target for the treatment of cancers. Targeting SPHK1 would provide new strategies for cancer treatment and improve the prognosis of cancer patients. Here we review and summarize the current research findings on the SPHK1-S1P axis in cancer from many aspects including structure, expression, regulation, mechanism, and potential inhibitors.

Metabolic adaptation of cancer and immune cells mediated by hypoxia-inducible factors

Cancer cells are characterized by high metabolic demand. The substrates in demand include oxygen, glucose, glutamine and lipids. Oxygen serves as a key substrate in cellular metabolism and bioenergetics. Hypoxia or low oxygen abundance is a common feature of the tumor microenvironment that occurs due to an imbalance in supply and demand. Many of the metabolic responses to hypoxia in both cancer cells and stromal cells are orchestrated by hypoxia-inducible factors (HIFs). In this review we summarize our current understanding of how HIFs modulate the metabolism of hypoxic cancer cells and immune cells, and how altered metabolism plays a role in cancer progression.

Sphingolipids and Redox Signaling in Renal Regulation and Chronic Kidney Diseases

Significance: Sphingolipids play critical roles in the membrane biology and intracellular signaling events that influence cellular behavior and function. Our review focuses on the cellular mechanisms and functional relevance of the cross talk between sphingolipids and redox signaling, which may be critically implicated in the pathogenesis of different renal diseases. Recent Advances: Reactive oxygen species (ROS) and sphingolipids can regulate cellular redox homeostasis through the regulation of NADPH oxidase, mitochondrial integrity, nitric oxide synthase (NOS), and antioxidant enzymes. Over the last two decades, there have been significant advancements in the field of sphingolipid research, and it was in 2010 for the first time that sphingolipid receptor modulator was exploited as a therapeutic in humans. The cross talk of sphingolipids with redox signaling pathways becomes an important mechanism in the development of many different diseases such as renal diseases. Critical Issues: The critical issues to be addressed in this review are how sphingolipids interact with the redox signaling pathway to regulate renal function and even result in chronic kidney diseases. Ceramide, sphingosine, and sphingosine-1-phosphate (S1P) as main signaling sphingolipids are discussed in more detail. Future Directions: Although sphingolipids and ROS may mediate or modulate cellular responses to physiological and pathological stimuli, more translational studies and mechanistic pursuit in a tissue- or cell-specific way are needed to enhance our understanding of this important topic and to develop effective therapeutic strategies to treat diseases associated with redox signaling and sphingolipid cross talk. Antioxid. Redox Signal. 28, 1008-1026.

Postoperative adjuvant TACE for patients of hepatocellular carcinoma in AJCC stage I: friend or foe? a propensity score analysis

BACKGROUND

Although the transcatheter arterial chemoembolization (TACE) was demonstrated to be an alternative treatment of hepatocellular carcinoma with favorable oncological effect, the benefit of postoperative adjuvant TACE was still controversial. The aim of this study was to evaluate the effect of postoperative TACE in hepatocellular carcinoma.

RESULTS

The 1, 3, and 5-year overall and disease-free survival rates were comparable between Surgery+TACE and Surgery groups. In subgroup analysis, tumor size (≥ 5 cm) was detrimental to disease-free survival (p = 0.028) and an inferior tendency of overall survival was presented. Besides, repeated TACE for patients contributed to a poor disease-free survival (p = 0.005). While, postoperative adjuvant TACE improved the overall survival in patients with high preoperative alpha-fetoprotein or positive pathologically (p = 0.039 and p = 0.045).

MATERIALS AND METHODS

The data were collected from consecutive patients between January 2010 and September 2014. After propensity score matching, baseline characteristics, overall and disease-free survival were compared between two groups. Subsequently, univariate and subgroup analysis were carried on.

CONCLUSIONS

Our study indicated that single postoperative adjuvant TACE was beneficial for selected patients of stage I with tumor less than 5 cm, or high preoperative alpha-fetoprotein in serum or positive of alpha-fetoprotein pathologically.

Identification and characterization of the druggable kinase targets of olmesartan and its analogues from a systematic kinase-chemical interaction profile in atherosclerosis

Olmesartan (OL) is the pharmacologically active metabolite of Olmesartan medoxomil (OM), an FDA-approved angiotensin II receptor antagonist for administrating cardiovascular diseases. The drug has been found to have potential effects on diverse protein kinase signaling involved in the pathogenesis of atherosclerosis, either by directly inhibiting the hub kinases or by indirectly modulating marginal members in the signaling pathways. In the present study, we computationally model the kinase-chemical Interaction Profile between six OL-related chemicals (i.e. OL, OM, Valsartan [VL], Losartan [LS], Candesartan [CD] and Telmisartan [TL]) and 23 human protein kinases in atherosclerosis. The profile is analyzed systematically at molecular level to identify unexpected kinase targets for OL. There is a good consistence between co-citation frequency and affinity scoring for the chemical association with kinase candidates; the OL and its analogs VL and LS exhibit a similar binding profile to the atherosclerosis kinase spectrum. It is suggested that the Ser/Thr-specific kinases PI3Kα and ROCK1 are potential druggable targets of OL for atherosclerosis therapy. As a paradigm, kinase assays reveal that the inhibitory potency of OL and Y-27632 (positive control) on ROCK1 is determined at micromolar level, while the OM (negative control) possesses no detectable activity for the kinase.