Statins are active in acute lymphoblastic leukaemia (ALL): a therapy that may treat ALL and prevent avascular necrosis

Leveraging altered lipid metabolism in treating B cell malignancies

B cell malignancies, comprising over 80 heterogeneous blood cancers, pose significant prognostic challenges due to intricate oncogenic signaling. Emerging evidence emphasizes the pivotal role of disrupted lipid metabolism in the development of these malignancies. Variations in lipid species, such as phospholipids, cholesterol, sphingolipids, and fatty acids, are widespread across B cell malignancies, contributing to uncontrolled cell proliferation and survival. Phospholipids play a crucial role in initial signaling cascades leading to B cell activation and malignant transformation through constitutive B cell receptor (BCR) signaling. Dysregulated cholesterol and sphingolipid homeostasis support lipid raft integrity, crucial for propagating oncogenic signals. Sphingolipids impact malignant B cell stemness, proliferation, and survival, while glycosphingolipids in lipid rafts modulate BCR activation. Additionally, cancer cells enhance fatty acid-related processes to meet heightened metabolic demands. In obese individuals, the obesity-derived lipids and adipokines surrounding adipocytes rewire lipid metabolism in malignant B cells, evading cytotoxic therapies. Genetic drivers such as MYC translocations also intrinsically alter lipid metabolism in malignant B cells. In summary, intrinsic and extrinsic factors converge to reprogram lipid metabolism, fostering aggressive phenotypes in B cell malignancies. Therefore, targeting altered lipid metabolism has translational potential for improving risk stratification and clinical management of diverse B cell malignancy subtypes.

CCR9 overexpression promotes T-ALL progression by enhancing cholesterol biosynthesis

Introduction: T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy of the lymphoid progenitor cells, contributing to ∼ 20% of the total ALL cases, with a higher prevalence in adults than children. Despite the important role of human T-ALL cell lines in understanding the pathobiology of the disease, a detailed comparison of the tumorigenic potentials of two commonly used T-ALL cell lines, MOLT4 and JURKAT cells, is still lacking. Methodology: In the present study, NOD-Prkdc scid IL2rgd ull (NTG) mice were intravenously injected with MOLT4, JURKAT cells, and PBS as a control. The leukemiac cell homing/infiltration into the bone marrow, blood, liver and spleen was investigated for bioluminescence imaging, flow cytometry, and immunohistochemistry staining. Gene expression profiling of the two cell lines was performed via RNA-seq to identify the differentially expressed genes (DEGs). CCR9 identified as a DEG, was further screened for its role in invasion and metastasis in both cell lines in vitro. Moreover, a JURKAT cell line with overexpressed CCR9 (Jurkat-OeCCR9) was investigated for T-ALL formation in the NTG mice as compared to the GFP control. Jurkat-OeCCR9 cells were then subjected to transcriptome analysis to identify the genes and pathways associated with the upregulation of CCR9 leading to enhanced tumirogenesis. The DEGs of the CCR9-associated upregulation were validated both at mRNA and protein levels. Simvastatin was used to assess the effect of cholesterol biosynthesis inhibition on the aggressiveness of T-ALL cells. Results: Comparison of the leukemogenic potentials of the two T-ALL cell lines showed the relatively higher leukemogenic potential of MOLT4 cells, characterized by their enhanced tissue infiltration in NOD-PrkdcscidIL2rgdull (NTG) mice. Transcriptmoe analysis of the two cell lines revealed numerous DEGs, including CCR9, enriched in vital signaling pathways associated with growth and proliferation. Notably, the upregulation of CCR9 also promoted the tissue infiltration of JURKAT cells in vitro and in NTG mice. Transcriptome analysis revealed that CCR9 overexpression facilitated cholesterol production by upregulating the expression of the transcriptional factor SREBF2, and the downstream genes: MSMO1, MVD, HMGCS1, and HMGCR, which was then corroborated at the protein levels. Notably, simvastatin treatment reduced the migration of the CCR9-overexpressing JURKAT cells, suggesting the importance of cholesterol in T-ALL progression. Conclusions: This study highlights the distinct tumorigenic potentials of two T-ALL cell lines and reveals CCR9-regulated enhanced cholesterol biosynthesis in T-ALL.

Genome-wide CRISPR screens identify ferroptosis as a novel therapeutic vulnerability in acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most frequent cancer diagnosed in children. Despite the great progress achieved over the last 40 years, with cure rates now exceeding 85%, refractory or relapsed ALL still exhibit a dismal prognosis. This poor outcome reflects the lack of treatment options specifically targeting relapsed or refractory ALL. In order to address this gap, we performed whole-genome CRISPR/Cas drop-out screens on a panel of seven B-ALL cell lines. Our results demonstrate that while there was a significant overlap in gene essentiality between ALL cell lines and other cancer types survival of ALL cell lines was dependent on several unique metabolic pathways, including an exquisite sensitivity to GPX4 depletion and ferroptosis induction. Detailed molecular analysis of B-ALL cells suggest that they are primed to undergo ferroptosis as they exhibit high steady-state oxidative stress potential, a low buffering capacity, and a disabled GPX4-independent secondary lipid peroxidation detoxification pathway. Finally, we validated the sensitivity of BALL to ferroptosis induction using patient-derived B-ALL samples.

Pitavastatin Is Anti-Leukemic in a Bone Marrow Microenvironment Model of B-Lineage Acute Lymphoblastic Leukemia

Simple Summary

Chemoresistance after chemotherapy is a negative prognostic indicator for B-cell acute lymphoblastic leukemia (ALL), necessitating the search for novel therapies. By growing ALL cells together with bone marrow stromal cells, we developed a chemoresistant ALL model. Using this model, we found that the lipid lowering drug pitavastatin had antileukemic activity in this chemoresistant co-culture model. Our data suggests that pitavastatin may be a novel treatment option for repurposing in chemoresistant, relapse ALL.

Abstract

The lack of complete therapeutic success in the treatment of B-cell acute lymphoblastic leukemia (ALL) has been attributed, in part, to a subset of cells within the bone marrow microenvironment that are drug resistant. Recently, the cholesterol synthesis inhibitor, pitavastatin (PIT), was shown to be active in acute myeloid leukemia, prompting us to evaluate it in our in vitro co-culture model, which supports a chemo-resistant ALL population. We used phospho-protein profiling to evaluate the use of lipid metabolic active compounds in these chemo-resistant cells, due to the up-regulation of multiple active survival signals. In a co-culture with stromal cells, a shift towards anabolic processes occurred, which was further confirmed by assays showing increased lipid content. The treatment of REH leukemia cells with pitavastatin in the co-culture model resulted in significantly higher leukemic cell death than exposure to the standard-of-care chemotherapeutic agent, cytarabine (Ara-C). Our data demonstrates the use of pitavastatin as a possible alternative treatment strategy to improve patient outcomes in chemo-resistant, relapsed ALL.

Bisphosphonate Combination Therapy in the Management of Postchemotherapy Avascular Necrosis of the Femoral Head in Adolescents and Young Adults: A Retrospective Study From India

Purpose

With improved survival after chemotherapy for acute lymphoblastic leukemia (ALL), it is imperative to maintain good quality of life as part of the management of post-therapy adverse effects. Avascular necrosis of the femoral head (AVNFH) is one such adverse effect. A need exists for a therapy that ameliorates discomfort, provides a productive life, is cost effective, and is joint preservative. We conducted the current study to evaluate the response to bisphosphonate in the nonsurgical management of AVNFH in adolescents and young adults (AYA) who receive treatment for ALL.

Materials and Methods

This is a retrospective study of 20 AYA patients—34 affected hips—who received zolendronic acid 5 mg intravenously each year along with oral alendronate 70 mg weekly for 3 years. Clinical evaluation was performed by using the Visual Analog Scale and the Harris Hip Score. Radiographs were used to classify the Ficat-Arlet stage, monitor radiologic collapse, and evaluate the rate of progression.

Results

Pain relief with a drop in the Visual Analog Scale score was observed at a mean duration of 5.2 weeks (range, 3 weeks to 11 weeks) after the start of therapy. Radiologic progression by one grade was observed in 12 hips (35.3%), and only one hip (2.94%) showed progression by two grades. At a mean follow-up of 50.3 months, 31 affected hips (91.1%) had a satisfactory clinical outcome and had not required any surgical intervention. The proportion of hips that required total hip arthroplasty were 0%, 5%, and 22.2% in Ficat-Arlet stage I, II, and III, respectively.

Conclusion

The combination of intravenous zolendronic acid and oral alendronate provides a pragmatic solution for the management of AVNFH after therapy for ALL in AYA patients. This therapy is safe, effective, and well tolerated.

The Roles of Cholesterol and Its Metabolites in Normal and Malignant Hematopoiesis

Hematopoiesis is sustained throughout life by hematopoietic stem cells (HSCs) that are capable of self-renewal and differentiation into hematopoietic progenitor cells (HPCs). There is accumulating evidence that cholesterol homeostasis is an important factor in the regulation of hematopoiesis. Increased cholesterol levels are known to promote proliferation and mobilization of HSCs, while hypercholesterolemia is associated with expansion of myeloid cells in the peripheral blood and links hematopoiesis with cardiovascular disease. Cholesterol is a precursor to steroid hormones, oxysterols, and bile acids. Among steroid hormones, 17β-estradiol (E2) induces HSC division and E2-estrogen receptor α (ERα) signaling causes sexual dimorphism of HSC division rate. Oxysterols are oxygenated derivatives of cholesterol and key substrates for bile acid synthesis and are considered to be bioactive lipids, and recent studies have begun to reveal their important roles in the hematopoietic and immune systems. 27-Hydroxycholesterol (27HC) acts as an endogenous selective estrogen receptor modulator and induces ERα-dependent HSC mobilization and extramedullary hematopoiesis. 7α,25-dihydroxycholesterol (7α,25HC) acts as a ligand for Epstein-Barr virus-induced gene 2 (EBI2) and directs migration of B cells in the spleen during the adaptive immune response. Bile acids serve as chemical chaperones and alleviate endoplasmic reticulum stress in HSCs. Cholesterol metabolism is dysregulated in hematologic malignancies, and statins, which inhibit de novo cholesterol synthesis, have cytotoxic effects in malignant hematopoietic cells. In this review, recent advances in our understanding of the roles of cholesterol and its metabolites as signaling molecules in the regulation of hematopoiesis and hematologic malignancies are summarized.

Combination statin and chemotherapy inhibits proliferation and cytotoxicity of an aggressive natural killer cell leukemia

Background

Aggressive natural killer cell leukemia is a devastating disease, with an average patient survival time of less than 2 months following diagnosis. Due to P-glycoprotein-mediated resistance of the tumor cells most forms of chemotherapy are of limited efficacy, therefore new treatment strategies are needed. Statin drugs have recently been found to inhibit the growth of various tumor cell types.

Methods

We investigated the effects of statin drug-mediated mevalonate pathway inhibition on cell proliferation, tumor-induced cytotoxicity, cell cycle progression and ERK MAP kinase signal transduction pathway activation. Flow cytometry was used to perform the cytotoxicity and cell cycle analyses and Western blotting was used to investigate ERK MAP kinase activation. Statistical significance was assessed by Student’s t-test.

Results

Fluvastatin and atorvastatin were found to inhibit cell growth and tumor-induced cytotoxicity. These effects were reversed by the addition of mevalonate, signifying that the impact of the drugs were on the mevalonate pathway. Both drugs affected cell cycle progression by causing a significant increase in the percentage of cells in the G0/G1 phase and a reduction in the S phase and the G2/M phases of the cell cycle. Low concentrations of statin drugs were able to abrogate ERK MAP kinase pathway activation, which is typically constitutively activated in aggressive natural killer cell leukemias and important in tumor-mediated cytotoxicity. Addition of statins to chemotherapy caused enhanced inhibition of cell growth and cytotoxicity, compared to either agent alone; a combination therapy that could conceivably benefit some patients.

Conclusions

These investigations suggest that inhibiting the mevalonate pathway might provide a more effective therapy against this deadly disease when combined with chemotherapy. Given that millions of people are currently taking statin drugs to lower cholesterol levels, the risk profile for statin drugs and their side effects are well-known. Our studies suggest that it may be beneficial to explore statin-chemotherapy combination in the treatment of aggressive natural killer cell leukemias.

The impact of high total cholesterol and high low-density lipoprotein on avascular necrosis of the femoral head in low-energy femoral neck fractures

Background

Avascular necrosis of the femoral head (AVNFH) typically constitutes 5 to 15% of all complications of low-energy femoral neck fractures, and due to an increasingly ageing population and a rising prevalence of femoral neck fractures, the number of patients who develop AVNFH is increasing. However, there is no consensus regarding the relationship between blood lipid abnormalities and postoperative AVNFH. The purpose of this retrospective study was to investigate the relationship between blood lipid abnormalities and AVNFH following the femoral neck fracture operation among an elderly population.

Methods

A retrospective, comparative study was performed at our institution. Between June 2005 and November 2009, 653 elderly patients (653 hips) with low-energy femoral neck fractures underwent closed reduction and internal fixation with cancellous screws (Smith and Nephew, Memphis, Tennessee). Follow-up occurred at 1, 6, 12, 18, 24, 30, and 36 months after surgery. Logistic multi-factor regression analysis was used to assess the risk factors of AVNFH and to determine the effect of blood lipid levels on AVNFH development. Inclusion and exclusion criteria were predetermined to focus on isolated freshly closed femoral neck fractures in the elderly population. The primary outcome was the blood lipid levels. The secondary outcome was the logistic multi-factor regression analysis.

Results

A total of 325 elderly patients with low-energy femoral neck fractures (AVNFH, n = 160; control, n = 165) were assessed. In the AVNFH group, the average TC, TG, LDL, and Apo-B values were 7.11 ± 3.16 mmol/L, 2.15 ± 0.89 mmol/L, 4.49 ± 1.38 mmol/L, and 79.69 ± 17.29 mg/dL, respectively; all of which were significantly higher than the values in the control group. Logistic multi-factor regression analysis showed that both TC and LDL were the independent factors influencing the postoperative AVNFH within femoral neck fractures.

Conclusions

This evidence indicates that AVNFH was significantly associated with blood lipid abnormalities in elderly patients with low-energy femoral neck fractures. The findings of this pilot trial justify a larger study to determine whether the result is more generally applicable to a broader population.

Leukemia cells display lower levels of intracellular cholesterol irrespective of the exogenous cholesterol availability

BACKGROUND

Different types of cancer cells are previously shown to accumulate intracellular cholesterol. However, the data on intracellular cholesterol levels in leukemia cells provide contradictory evidence. Various previous works indicate either increase, decrease or no difference in total cholesterol levels between leukemia cells and healthy peripheral blood mononuclear cells (PBMCs).

METHODS

We studied the intracellular cholesterol levels in acute myeloid leukemia (AML) and acute lymphocytic leukemia (ALL) cells and compared with that in PBMCs from the healthy subjects.

RESULTS

We observed that the PBMCs from AML (n=7) and ALL (n=7) patients displayed significantly lower intracellular levels of total cholesterol in comparison to PBMCs from the healthy subjects (n=26). Consistent with the patient data the ALL (CCRF-CEM and MOLT-3) and AML (KG-1 and THP-1) cell lines also displayed significantly lower intracellular levels of total cholesterol. We confirmed this observation using multiple methodological approaches. Both ALL and AML cell lines also displayed significantly lower levels of free cholesterol and cholesteryl ester contents in comparison to normal hematopoietic cells. We observed that >90% of the total cholesterol in leukemia cells as well as in normal PBMCs was present in the form of cholesteryl esters. It was also observed that the lower levels of cholesterol in leukemia cells are not affected by exogenous cholesterol availability.

CONCLUSIONS

Present study provides convincing evidence to prove that the cellular free cholesterol and cholesteryl ester content is significantly reduced in leukemia cells in comparison to normal hematopoietic cells in circulation. Moreover, it was shown that the lower levels of cholesterol in leukemia cells are not affected by exogenous cholesterol availability.

HMG-CoA reductase inhibitors as adjuvant treatment for hematologic malignancies: what is the current evidence?

Statins have been shown to possess properties that go beyond their lipid-lowering effects. These agents act on the mevalonate pathway and inhibit synthesis of cholesterol, geranylgeranyl pyrophosphate, and farnesyl pyrophosphate, which are necessary for posttranslational modification of the Rho, Rac, and Ras superfamily of proteins. Early phase studies have demonstrated that this modulation of cellular signaling can ultimately exert pro-apoptotic, anti-angiogenic, and immunomodulatory effects, and might even restore chemosensitivity in several hematologic cancers. Nonetheless, these promising preclinical results have not yet migrated from the bench to the bedside as their effectiveness as adjuvant agents in hematologic malignancies is currently uncertain. In the present review, we summarize the existing evidence stemming from preclinical and clinical studies pertaining to the use of statins as adjuvant therapies in hematologic malignancies, and discuss the new insights gained from the ongoing translational research.

Development of an evidence-based clinical guideline for age-appropriate screening, prevention, and management of bone abnormalities in children post-hematopoietic stem cell transplant

Musculoskeletal complaints, pain, and weakness are common among children post-hematopoietic stem cell transplant (HSCT). Bone abnormalities include decreased bone mineral density and avascular necrosis, both affecting ambulation and quality of life for survivors. Several risk factors for both disorders among adults have been described along with suggested interventions. However, similar recommendations for screening and management of bone abnormalities among children and adolescents post-HSCT are not clearly defined. A review of the literature using PubMed, CINAHL, National Guideline Clearinghouse, and Cochrane Collection databases identified a paucity of reports specific to the management of bone abnormalities in children and adolescents post-HSCT. Although guidelines for evaluation of bone health in pediatric patients with cancer exist, none specifically address early screening and prevention. The purpose of this article is to provide a review of the literature on current evidence for age appropriate screening, prevention, and management of bone abnormalities in children post-HSCT and to present a clinical guideline for bone abnormalities in children post-HSCT used in a hospital-based outpatient center.