Increased Lipogenesis Is Important for Hexavalent Chromium-Transformed Lung Cells and Xenograft Tumor Growth

Hexavalent chromium, Cr(VI), is a known carcinogen and environmental health concern. It has been established that reactive oxygen species, genomic instability, and DNA damage repair deficiency are important contributors to the Cr(VI)-induced carcinogenesis mechanism. However, some hallmarks of cancer remain under-researched regarding the mechanism behind Cr(VI)-induced carcinogenesis. Increased lipogenesis is important to carcinogenesis and tumorigenesis in multiple types of cancers, yet the role increased lipogenesis has in Cr(VI) carcinogenesis is unclear. We report here that Cr(VI)-induced transformation of three human lung cell lines (BEAS-2B, BEP2D, and WTHBF-6) resulted in increased lipogenesis (palmitic acid levels), and Cr(VI)-transformed cells had an increased expression of key lipogenesis proteins (ATP citrate lyase [ACLY], acetyl-CoA carboxylase [ACC1], and fatty acid synthase [FASN]). We also determined that the Cr(VI)-transformed cells did not exhibit an increase in fatty acid oxidation or lipid droplets compared to their passage-matched control cells. Additionally, we observed increases in ACLY, ACC1, and FASN in lung tumor tissue compared with normal-adjacent lung tissue (in chromate workers that died of chromate-induced tumors). Next, using a known FASN inhibitor (C75), we treated Cr(VI)-transformed BEAS-2B with this inhibitor and measured cell growth, FASN protein expression, and growth in soft agar. We observed that FASN inhibition results in a decreased protein expression, decreased cell growth, and the inhibition of colony growth in soft agar. Next, using shRNA to knock down the FASN protein in Cr(VI)-transformed BEAS-2B cells, we saw a decrease in FASN protein expression and a loss of the xenograft tumor development of Cr(VI)-transformed BEAS-2B cells. These results demonstrate that FASN is important for Cr(VI)-transformed cell growth and cancer properties. In conclusion, these data show that Cr(VI)-transformation in vitro caused an increase in lipogenesis, and that this increase is vital for Cr(VI)-transformed cells.

Recent advancements in nanomedicine based lipid metabolism for tumour immunotherapy

Therapy on lipid metabolism is emerging as a groundbreaking cancer treatment, offering the unprecedented opportunity to effectively treat and in several cases. Tumorigenesis is inextricably linked to lipid metabolism. In this regard, the features of lipid metabolism include lipid synthesis, decomposition, metabolism and lipid storage and mobilisation from intracellular lipid droplets. Most importantly, the regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects. Different cancers and immune cells have different dependence on lipid metabolism, playing a pivotal role in differentiation and function of immune cells. However, what lies before the immunotherapy targeting lipid metabolism is side effects of systemic toxicity and defects of individual drugs, which strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies. This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells and their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.HighlightsThe regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects.Preparations of focusing lipid metabolism have side effects of systemic toxicity and defects of individual drugs. It strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies.This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells as well as their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.

Physiological and pathological roles of lipogenesis

Lipids are essential metabolites, which function as energy sources, structural components and signalling mediators. Most cells are able to convert carbohydrates into fatty acids, which are often converted into neutral lipids for storage in the form of lipid droplets. Accumulating evidence suggests that lipogenesis plays a crucial role not only in metabolic tissues for systemic energy homoeostasis but also in immune and nervous systems for their proliferation, differentiation and even pathophysiological roles. Thus, excessive or insufficient lipogenesis is closely associated with aberrations in lipid homoeostasis, potentially leading to pathological consequences, such as dyslipidaemia, diabetes, fatty liver, autoimmune diseases, neurodegenerative diseases and cancers. For systemic energy homoeostasis, multiple enzymes involved in lipogenesis are tightly controlled by transcriptional and post-translational modifications. In this Review, we discuss recent findings regarding the regulatory mechanisms, physiological roles and pathological importance of lipogenesis in multiple tissues such as adipose tissue and the liver, as well as the immune and nervous systems. Furthermore, we briefly introduce the therapeutic implications of lipogenesis modulation.

Impact of genetic variants involved in the lipid metabolism pathway on progression free survival in patients receiving bevacizumab-based chemotherapy in metastatic colorectal cancer: a retrospective analysis of FIRE-3 and MAVERICC trials

BACKGROUND

Antiangiogenic drug (AAD)-triggered oxygen and nutrient depletion through suppression of angiogenesis switches glucose-dependent to lipid-dependent metabolism. Blocking fatty acid oxidation can enhance AAD-mediated anti-tumor effects in colorectal cancer (CRC). Therefore, we hypothesised that genetic variants in the lipid metabolism pathway may predict clinical outcomes [overall response rate (ORR), overall survival (OS) and progression-free survival (PFS)] in metastatic CRC (mCRC) patients receiving bevacizumab-based first-line treatment.

METHODS

Genomic DNA from blood samples of patients enrolled in FIRE-3 (a global, randomised, open-label, phase 3 trial, between 2007-6-23 and 2012-9-19, discovery cohort: FOLFIRI/bevacizumab arm, n = 107; control cohort: FOLFIRI/cetuximab arm, n = 129) and MAVERICC (a global, randomised, open-label, phase II study, between 2011-8 and 2015-7, in United States, Canada, Estonia, Ireland, Switzerland, Norway, and Portugal. Validation cohort: FOLFIRI/bevacizumab arm, n = 163) trials, was genotyped using the OncoArray-500 K beadchip panel. The impact on OS and PFS of 17 selected SNPs in 7 genes involved in the lipid metabolism pathway (CD36, FABP4, LPCAT1/2, CPT1A, FASN, ACACA) was analysed using Kaplan-Meier curves, the log-rank test for univariate analyses and likelihood ratio tests of Cox proportional hazards regression parameters for multivariable analyses. ORR and SNP associations were evaluated using Chi-square or Fisher's exact tests.

FINDINGS

In the discovery cohort, patients with FASN rs4485435 any C allele (n = 21) showed significantly shorter PFS (median PFS: 8.69 vs 13.48 months) compared to carriers of G/G (n = 62) in multivariable (HR = 2.87; 95%CI 1.4-5.9; p = 0.00675) analysis. These data were confirmed in the validation cohort in multivariable analysis (HR = 2.07, 95%CI: 1.15-3.74; p = 0.02), but no association was observed in the cetuximab cohort of FIRE-3. In the comparison of bevacizumab vs cetuximab arm in FIRE-3, a significant interaction was shown with FASN rs4485435 (p = 0.017) on PFS.

INTERPRETATION

Our study demonstrates for the first time, to our knowledge, that FASN polymorphisms may predict outcome of bevacizumab-based treatment in patients with mCRC. These findings support a possible role of the lipid metabolism pathway in contributing to resistance to anti-VEGF treatment.

FUNDING

This work was supported by the National Cancer Institute [P30CA 014089 to H.-J.L.], Gloria Borges WunderGlo Foundation, Dhont Family Foundation, Victoria and Philip Wilson Research Fund, San Pedro Peninsula Cancer Guild, Ming Hsieh Research Fund, Eddie Mahoney Memorial Research Fund, Shanghai Sailing Program (22YF1407000), China National Postdoctoral Program for Innovative Talents (BX20220084), China Postdoctoral Science Foundation (2022M710768), National Natural Science Foundation of China (82202892).

Fc receptor-like 1, 3, and 6 variants are associated with rheumatoid arthritis risk in the Chinese Han population

BACKGROUND

Rheumatoid arthritis (RA) is the most common autoimmune system diseases in our world. More studies in recent years have shown that FCRL gene polymorphisms is closely related to autoimmune diseases. It is suggested that genetic factors play a crucial role in the pathogenesis of this disease. In this study, we aimed to investigate the relationship between FCRL1 rs2050568, FCRL3 rs2317230 and FCRL6 rs58240276 polymorphisms and RA risk in the Chinese Han population. 506 with RA patients and 509 healthy controls were recruited in this study, and the single nucleotide polymorphisms (SNPs) was successfully genotyped using the Agena MassARRAY platform. Odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjusting for age and gender were conducted to assess these SNPs polymorphisms and RA risk. The multifactor dimensionality reduction (MDR) method was conducted to analyze SNP-SNP interaction.

RESULTS

Our results revealed that there no significant association was observed between the allele and genotype frequencies among these SNPs and RA risk (all p > 0.05). Straified analysis by age and gender, the results confirmed that FCRL1 rs2050568 T/T genotype enhanced the risk of RA in females (p = 0.014). The G/T - T/T genotype of FCRL3 rs2317230 was correlated with a decreased RA risk in males (p = 0.021). We also observed that the C/T-T/T genotype of FCRL6 rs58240276 was increased the risk of RA in the group at age >  54 years (p = 0.016). In addition, FCRL1 rs2050568-TT, FCRL6 rs58240276-TT and FCRL1 rs2050568-TT, FCRL3 rs2317230-TT, FCRL6 rs58240276-TT are the best models for multi-site MDR analysis (p < 0.05), and the two best models mentioned above and classes RA have the most significant correlation.

CONCLUSIONS

Our study demonstrated that FCRL1 rs2050568, FCRL3 rs2317230, and FCRL6 rs58240276 polymorphisms were correlated with RA susceptibility in the Chinese Han population.

Alterations of Lipid Metabolism in Cancer: Implications in Prognosis and Treatment

Cancer remains the second leading cause of mortality worldwide. In the course of this multistage and multifactorial disease, a set of alterations takes place, with genetic and environmental factors modulating tumorigenesis and disease progression. Metabolic alterations of tumors are well-recognized and are considered as one of the hallmarks of cancer. Cancer cells adapt their metabolic competences in order to efficiently supply their novel demands of energy to sustain cell proliferation and metastasis. At present, there is a growing interest in understanding the metabolic switch that occurs during tumorigenesis. Together with the Warburg effect and the increased glutaminolysis, lipid metabolism has emerged as essential for tumor development and progression. Indeed, several investigations have demonstrated the consequences of lipid metabolism alterations in cell migration, invasion, and angiogenesis, three basic steps occurring during metastasis. In addition, obesity and associated metabolic alterations have been shown to augment the risk of cancer and to worsen its prognosis. Consequently, an extensive collection of tumorigenic steps has been shown to be modulated by lipid metabolism, not only affecting the growth of primary tumors, but also mediating progression and metastasis. Besides, key enzymes involved in lipid-metabolic pathways have been associated with cancer survival and have been proposed as prognosis biomarkers of cancer. In this review, we will analyze the impact of obesity and related tumor microenviroment alterations as modifiable risk factors in cancer, focusing on the lipid alterations co-occurring during tumorigenesis. The value of precision technologies and its application to target lipid metabolism in cancer will also be discussed. The degree to which lipid alterations, together with current therapies and intake of specific dietary components, affect risk of cancer is now under investigation, and innovative therapeutic or preventive applications must be explored.

The vital role of ATP citrate lyase in chronic diseases

Chronic or non-communicable diseases are the leading cause of death worldwide; they usually result in long-term illnesses and demand long-term care. Despite advances in molecular therapeutics, specific biomarkers and targets for the treatment of these diseases are required. The dysregulation of de novo lipogenesis has been found to play an essential role in cell metabolism and is associated with the development and progression of many chronic diseases; this confirms the link between obesity and various chronic diseases. The main enzyme in this pathway-ATP-citrate lyase (ACLY), a lipogenic enzyme-catalyzes the critical reaction linking cellular glucose catabolism and lipogenesis. Increasing lines of evidence suggest that the modulation of ACLY expression correlates with the development and progressions of various chronic diseases such as neurodegenerative diseases, cardiovascular diseases, diabetes, obesity, inflammation, and cancer. Recent studies suggest that the inhibition of ACLY activity modulates the glycolysis and lipogenesis processes and stimulates normal physiological functions. This comprehensive review aimed to critically evaluate the role of ACLY in the development and progression of different diseases and the effects of its downregulation in the prevention and treatment of these diseases.

COL6A3 polymorphisms were associated with lung cancer risk in a Chinese population

Background

Lung cancer is one of the leading cause of cancer-related death in the world. Recently, many clinical researches have reported that COL6A3 had strong role in many diseases. The aim of this study was to evaluate the association between single nucleotide polymorphisms (SNPs) in COL6A3 and lung cancer susceptibility.

Method

Eight variants in COL6A3 were genotyped in a Chinese Han population including 510 cases and 495 controls using Agena MassARRAY. Genetic models and haplotype analyses were used to calculate the association between COL6A3 SNPs and lung cancer risk. And we assessed the relative risk by the odds ratio (OR) and 95% confidence interval (CI).

Results

In our results, we observed that rs115510139 was linked to an increased risk of lung cancer in the codominant (adjusted OR = 1.61, 95%CI: 1.14–2.27, p = 0.007), dominant (adjusted OR = 1.36, 95%CI: 1.02–1.83, p = 0.037), recessive (adjusted OR = 1.41, 95%CI: 1.07–1.85, p = 0.015), and log-additive (adjusted OR = 1.27, 95%CI: 1.07–1.51, p = 0.006) models. After gender stratification analysis, we found that rs115510139, rs3736341 and rs12052971 were significant in males but were non-significant in females. Rs115510139 also can increase the risk of lung cancer in the population of age less than 61 years. When analyzed for the association with lung squamous carcinoma, rs13032404, rs115510139 and rs3736341 were related to the risk of lung cancer.

Conclusions

Our findings indicated potential associations between COL6A3 polymorphisms and lung cancer risk, which may contribute to the identification of lung cancer patients in a Chinese population.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1114-y) contains supplementary material, which is available to authorized users.

Pleiotrophin, a target of miR-384, promotes proliferation, metastasis and lipogenesis in HBV-related hepatocellular carcinoma

Hepatitis B virus (HBV) infection plays a crucial role and is a major cause of hepatocellular carcinoma (HCC) in China. microRNAs (miRNAs) have emerged as key players in hepatic steatosis and carcinogenesis. We found that down-regulation of miR-384 expression was a common event in HCC, especially HBV-related HCC. However, the possible function of miR-384 in HBV-related HCC remains unclear. The oncogene pleiotrophin (PTN) was a target of miR-384. HBx inhibited miR-384, increasing PTN expression. The PTN receptor N-syndecan was highly expressed in HCC. PTN induced by HBx acted as a growth factor via N-syndecan on hepatocytes and further promoted cell proliferation, metastasis and lipogenesis. PTN up-regulated sterol regulatory element-binding protein 1c (SREBP-1c) through the N-syndecan/PI3K/Akt/mTORC1 pathway and the expression of lipogenic genes, including fatty acid synthesis (FAS). PTN-mediated de novo lipid synthesis played an important role in HCC proliferation and metastasis. PI3K/AKT and an mTORC1 inhibitor diminished PTN-induced proliferation, metastasis and lipogenesis. Taken together, these data strongly suggest that the dysregulation of miR-384 could play a crucial role in HBV related to HCC, and the target gene of miR-384, PTN, represents a new potential therapeutic target for the prevention of hepatic steatosis and further progression to HCC after chronic HBV infection.

Targeting ATP-Citrate Lyase in Hyperlipidemia and Metabolic Disorders

Chronic overnutrition and a sedentary lifestyle promote imbalances in metabolism, often manifesting as risk factors for life-threating diseases such as atherosclerotic cardiovascular disease (ASCVD) and nonalcoholic fatty liver disease (NAFLD). Nucleocytosolic acetyl-coenzyme A (CoA) has emerged as a central signaling node used to coordinate metabolic adaptations in response to a changing nutritional status. ATP-citrate lyase (ACL) is the enzyme primarily responsible for the production of extramitochondrial acetyl-CoA and is thus strategically positioned at the intersection of nutrient catabolism and lipid biosynthesis. Here, we discuss recent findings from preclinical studies, as well as Mendelian and clinical randomized trials, demonstrating the importance of ACL activity in metabolism, and supporting its inhibition as a potential therapeutic approach to treating ASCVD, NAFLD, and other metabolic disorders.

ATP-citrate lyase: genetics, molecular biology and therapeutic target for dyslipidemia

PURPOSE OF REVIEW

ATP-citrate lyase (ACLY) has re-emerged as a drug target for LDL cholesterol (LDL-C) lowering. We review ACLY as a therapeutic strategy, its genetics, its molecular and cellular biology, and also its inhibition.

RECENT FINDINGS

ACLY is a critical enzyme linking glucose catabolism to lipogenesis by providing acetyl-CoA from mitochondrial citrate for fatty acid and cholesterol biosynthesis. Human genetic variants have been associated with enhanced growth and survival of several cancers, and with attenuated plasma triglyceride responses to dietary fish oil. In mice, liver-specific Acly deficiency protects from hepatic steatosis and dyslipidemia, whereas adipose tissue-specific Acly deletion has no phenotype, supporting therapeutic inhibition of ACLY. A lipid-regulating compound, bempedoic acid, was discovered to potently inhibit ACLY, and in animal models, it prevents dyslipidemia and attenuates atherosclerosis. Phase 2 clinical trials revealed that bempedoic acid effectively lowers LDL-C as monotherapy, combined with ezetimibe, added to statin therapy and in statin-intolerant hypercholesterolemic patients.

SUMMARY

The efficacy of bempedoic acid as an LDL-C-lowering agent has validated ACLY inhibition as a therapeutic strategy. Positive results of phase 3 patient studies, together with long-term cardiovascular disease outcome trials, are required to establish ACLY as a major new target in cardiovascular medicine.

Polymorphisms in genes of the de novo lipogenesis pathway and overall survival of hepatocellular carcinoma patients undergoing transarterial chemoembolization

Aberrant expression of genes in de novo lipogenesis (DNL) pathway were associated with various cancers, including hepatocellular carcinoma (HCC). Single nucleotide polymorphisms (SNPs) of DNL genes have been reported to be associated with prognosis of some malignancies. However, the effects of SNPs in DNL genes on overall survival of HCC patients receiving transarterial chemoembolization (TACE) treatment are still unknown. In present study, nine SNPs in three genes (ACLY, ACACA and FASN) in DNL pathway were genotyped using the Sequenom iPLEX genotyping system in a hospital-based cohort with 419 HCC patients treated with TACE, and their associations with HCC overall survival were evaluated by Cox proportional hazard regression analysis under three genetic models (additive, dominant and recessive). Although we did not find any significant results in total analysis (all p>0.05), our stratified data showed that SNP rs9912300 in ACLY gene was significantly associated with overall survival of HCC patients with lower AFP level and SNP rs11871275 in ACACA gene was significantly associated with overall survival of HCC patients with higher AFP level. We further identified the significant interactions between AFP level and SNP rs9912300 or rs11871275 in the joint analysis. Conclusively, our data suggest that genetic variations in genes of DNL pathway may be a potential biomarker for predicting clinical outcome of HCC patients treated with TACE.