Upregulation of SCD1 by ErbB2 via LDHA promotes breast cancer cell migration and invasion

Unlocking the lipid code: SREBPs as key drivers in gastrointestinal tumour metabolism

In recent years, metabolic reprogramming has emerged as a significant breakthrough in elucidating the onset and progression of gastrointestinal (GI) malignancies. As central regulatory hubs for lipid metabolism, sterol regulatory element binding proteins (SREBPs) integrate dietary metabolic signals and carcinogenic stimuli through subtype-specific mechanisms, thereby promoting malignant tumour phenotypes. In this review, we first present the molecular background, structural characteristics, and posttranscriptional regulatory networks associated with SREBPs. We subsequently describe a systematic analysis of the distinct activation patterns of SREBPs in liver, gastric, colorectal, and other gastrointestinal cancers. Furthermore, we explore targeted intervention strategies for different SREBP subtypes, including small molecule inhibitors (such as fatostatin, which inhibits SREBP cleavage), natural compounds (such as berberine, which modulates the AMPK/mTOR pathway), and statin-mediated inhibition of the mevalonic acid pathway. These strategies may enhance tumour cell sensitivity to chemotherapeutic agents (such as 5-FU, gezil, and tabine) and improve the response to synergistic chemoradiotherapy by reversing adaptive metabolic resistance driven by the tumour microenvironment. Through this review, we hope to provide new insights into precise interventions targeting various subtypes of the SREBP molecule.

VIRMA-Mediated the m6A Methylation of SCD Facilitates Wilms' Tumor Progression via AMPK Pathway

Wilms' tumor (WT) is the most prevalent renal cancer in children. Numerous studies have shown that vir-like n6-methyladenosine (m6A) methyltransferase-associated protein (VIRMA), a necessary component and the largest methyltransferase, contributes to the advancement of multiple cancers. However, its function has not been characterized in WT. Hence, we examined the potential role of VIRMA in WT by analyzing its effect on the m6A modification of stearoyl-CoA desaturase (SCD). We utilized bioinformatics to narrow 12 differentially expressed (DE) genes in WT to a single gene. The expressions of SCD and VIRMA were analyzed via quantitative real-time PCR and western blotting. The influence of SCD on the malignancy attributes of WT cells and adenosine 5'-monophosphate-activated protein kinase (AMPK) signaling was assessed through Cell counting Kit-8, Ethynyl-2'-deoxyuridine, transwell, and western blotting assays. The specific interactions between SCD and VIRMA were confirmed through methylated RNA immunoprecipitation, western blotting, and RNA stability assays, followed by rescue experiments to show underlying mechanisms. The SCD expression was found to be elevated in WT samples. Furthermore, its silencing mitigated the malignant characteristics of WT cells while increasing the protein levels of key AMPK signaling molecules. Moreover, VIRMA was also upregulated in WT samples and demonstrated a positive association with SCD expression. The relative enrichment of SCD m6A, its protein, and its mRNA stability were enhanced in VIRMA-overexpressed WT cells. Mechanically, VIRMA overexpression accelerated the malignant phenotypes of WT cells by interacting with SCD. Overall, the results demonstrate that VIRMA-mediated m6A methylation of SCD promotes WT progression by modulating the AMPK pathway.

CircSCD1 inhibits ferroptosis in breast Cancer through stabilizing SCD1 protein via deubiquitinase OTUB1

Breast cancer is the leading cause of cancer-related death in women worldwide, and its developmental mechanisms involve complex factors. Recent studies have shown that ferroptosis is closely related to the occurrence and progression of breast cancer. However, the role of circular RNAs (circRNAs) in regulating ferroptosis in breast cancer remains unclear. In this study, we investigated the regulatory role of circSCD1 (hsa_circ_0019512) in breast cancer. We examined the expression of circSCD1 in breast cancer cell lines and explored its impact on cell viability and colony formation. We also evaluated the involvement of circSCD1 in ferroptosis by measuring the levels of malondialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), and intracellular iron. In vivo xenograft experiments were performed to confirm the role of circSCD1 in promoting tumor growth and inhibiting ferroptosis.Furthermore, we investigated the mechanism by which circSCD1 regulates SCD1 protein stability through ubiquitination and identified the interaction between circSCD1 and the deubiquitinase OTUB1. Our results showed that circSCD1 was upregulated in breast cancer cell lines and promoted cell viability and colony formation. Knockdown of circSCD1 increased MDA and ROS levels, decreased GSH levels, and enhanced ferroptosis in breast cancer cells. In vivo, circSCD1 knockdown significantly reduced tumor size and weight, while its overexpression enhanced tumor growth. Mechanistically, circSCD1 interacted with OTUB1 to inhibit the ubiquitination and degradation of SCD1 protein, thereby stabilizing its expression. Rescue experiments demonstrated that SCD1 overexpression partially reversed the effects of circSCD1 knockdown on cell proliferation and ferroptosis. Our findings suggest that circSCD1 plays a crucial role in promoting breast cancer cell growth and inhibiting ferroptosis by regulating SCD1 protein stability. Targeting the circSCD1/OTUB1/SCD1 axis may provide a potential therapeutic strategy for breast cancer treatment.

Lipid metabolic reprograming: the unsung hero in breast cancer progression and tumor microenvironment

Aberrant lipid metabolism is a well-recognized hallmark of cancer. Notably, breast cancer (BC) arises from a lipid-rich microenvironment and depends significantly on lipid metabolic reprogramming to fulfill its developmental requirements. In this review, we revisit the pivotal role of lipid metabolism in BC, underscoring its impact on the progression and tumor microenvironment. Firstly, we delineate the overall landscape of lipid metabolism in BC, highlighting its roles in tumor progression and patient prognosis. Given that lipids can also act as signaling molecules, we next describe the lipid signaling exchanges between BC cells and other cellular components in the tumor microenvironment. Additionally, we summarize the therapeutic potential of targeting lipid metabolism from the aspects of lipid metabolism processes, lipid-related transcription factors and immunotherapy in BC. Finally, we discuss the possibilities and problems associated with clinical applications of lipid‑targeted therapy in BC, and propose new research directions with advances in spatiotemporal multi-omics.

Targeting Dysregulated Lipid Metabolism in Cancer with Pharmacological Inhibitors

Metabolic plasticity is recognised as a hallmark of cancer cells, enabling adaptation to microenvironmental changes throughout tumour progression. A dysregulated lipid metabolism plays a pivotal role in promoting oncogenesis. Oncogenic signalling pathways, such as PI3K/AKT/mTOR, JAK/STAT, Hippo, and NF-kB, intersect with the lipid metabolism to drive tumour progression. Furthermore, altered lipid signalling in the tumour microenvironment contributes to immune dysfunction, exacerbating oncogenesis. This review examines the role of lipid metabolism in tumour initiation, invasion, metastasis, and cancer stem cell maintenance. We highlight cybernetic networks in lipid metabolism to uncover avenues for cancer diagnostics, prognostics, and therapeutics.

The lipid metabolism remodeling: A hurdle in breast cancer therapy

Lipids, as one of the three primary energy sources, provide energy for all cellular life activities. Lipids are also known to be involved in the formation of cell membranes and play an important role as signaling molecules in the intracellular and microenvironment. Tumor cells actively or passively remodel lipid metabolism, using the function of lipids in various important cellular life activities to evade therapeutic attack. Breast cancer has become the leading cause of cancer-related deaths in women, which is partly due to therapeutic resistance. It is necessary to fully elucidate the formation and mechanisms of chemoresistance to improve breast cancer patient survival rates. Altered lipid metabolism has been observed in breast cancer with therapeutic resistance, indicating that targeting lipid reprogramming is a promising anticancer strategy.

Lipid metabolic vulnerabilities of multiple myeloma

Multiple myeloma (MM) is the second most common hematological malignancy worldwide, characterized by abnormal proliferation of malignant plasma cells within a tumor-permissive bone marrow microenvironment. Metabolic dysfunctions are emerging as key determinants in the pathobiology of MM. In this review, we highlight the metabolic features of MM, showing how alterations in various lipid pathways, mainly involving fatty acids, cholesterol and sphingolipids, affect the growth, survival and drug responsiveness of MM cells, as well as their cross-talk with other cellular components of the tumor microenvironment. These findings will provide a new path to understanding the mechanisms underlying how lipid vulnerabilities may arise and affect the phenotype of malignant plasma cells, highlighting novel druggable pathways with a significant impact on the management of MM.

ErbB2-upregulated HK1 and HK2 promote breast cancer cell proliferation, migration and invasion

ErbB2 is overexpressed in 15-20% of breast cancer, which is associated with malignancy and poor prognosis. We previously reported that ErbB2 supports malignant progression of breast cancer by upregulating lactate dehydrogenase A (LDHA), an important enzyme in glycolysis. However, whether ErbB2 promotes breast cancer progression through other glycolytic enzymes remains unclear. Hexokinase 1 (HK1) and hexokinase 2 (HK2) are the first rate-limiting enzymes of glycolysis and both of them are increased in breast cancer. Here, we aim to investigate whether ErbB2 upregulates HK1 and HK2 and the role of HK1 and HK2 in the malignant progression of ErbB2-overexpressing breast cancer. In current study, we found that the mRNA level of ErbB2 was positively correlated with that of HK1 and HK2, respectively. Moreover, ErbB2 upregulated the protein levels of HK1 and HK2 in breast cancer cells. We also found that both siHK1 and siHK2 significantly inhibited the proliferation, migration and invasion of ErbB2-overexpressing breast cancer cells. Taken together, our findings suggested that ErbB2 promoted the malignant progression of breast cancer cells by upregulating HK1 and HK2, and HK1 and HK2 might serve as promising therapeutic targets for ErbB2-overexpressing breast cancer.