Hypoxia-induced SHMT2 protein lactylation facilitates glycolysis and stemness of esophageal cancer cells

Hypoxia promotes non-small cell lung cancer cell stemness, migration, and invasion via promoting glycolysis by lactylation of SOX9

BACKGROUND

Lung cancer is the deadliest form of malignancy and the most common subtype is non-small cell lung cancer (NSCLC). Hypoxia is a typical feature of solid tumor microenvironment. In the current study, we clarified the effects of hypoxia on stemness and metastasis and the molecular mechanism.

METHODS

The biological functions were assessed using the sphere formation assay, Transwell assay, and XF96 extracellular flux analyzer. The protein levels were detected by western blot. The lactylation modification was assessed by western blot and immunoprecipitation. The role of SOX9 in vivo was explored using a xenografted tumor model.

RESULTS

We observed that hypoxia promoted sphere formation, migration, invasion, glucose consumption, lactate production, glycolysis, and global lactylation. Inhibition of glycolysis suppressed cell stemness, migration, invasion, and lactylation. Moreover, hypoxia increased the levels of SOX9 and lactylation of SOX9, whereas inhibition of glycolysis reversed the increase. Additionally, knockdown of SOX9 abrogated the promotion of cell stemness, migration, and invasion. In tumor-bearing mice, overexpression of SOX9 promoted tumor growth, and inhibition of glycolysis suppressed tumor growth.

CONCLUSION

Hypoxia induced the lactylation of SOX9 to promote stemness, migration, and invasion via promoting glycolysis. The findings suggested that targeting hypoxia may be an effective way for NSCLC treatment and reveal a new mechanism of hypoxia in NSCLC.

Lactate-mediated lactylation in human health and diseases: Progress and remaining challenges

BACKGROUND

Lactate was once considered as metabolic waste for a long time. In 2019, Professor Zhao Yingming's team from the University of Chicago found that lactate could also be used as a substrate to induce histone lactylation and regulate gene expression. Since then, researchers have discovered that lactate-mediated lactylation play important regulatory roles in various physiological and pathological processes.

AIM OF REVIEW

In this review, we aim to discuss the roles and mechanisms of lactylation in human health and diseases, as well as the effects of lactylation on proteins and metabolic modulators targeting lactylation.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In this work, we emphasize the crucial regulatory roles of lactylation in the development of numerous physiological and pathological processes. Of relevance, we discuss the current issues and challenges pertaining to lactylation. This review provides directions and a theoretical basis for future research and clinical translation of lactylation.

Hypoxia exposure induces lactylation of Axin1 protein to promote glycolysis of esophageal carcinoma cells

The hypoxic microenvironment in esophageal carcinoma is an important factor promoting the rapid progression of malignant tumor. This study was to investigate the lactylation of Axin1 on glycolysis in esophageal carcinoma cells under hypoxia exposure. Hypoxia treatment increases pan lysine lactylation (pan-kla) levels of both TE1 and EC109 cells. Meanwhile, ECAR, glucose consumption and lactate production were also upregulated in both TE1 and EC109 cells. The expression of embryonic stem cell transcription factors NANOG and SOX2 were enhanced in the hypoxia-treated cells. Axin1 overexpression partly reverses the induction effects of hypoxia treatment in TE1 and EC109 cells. Moreover, lactylation of Axin1 protein at K147 induced by hypoxia treatment promotes ubiquitination modification of Axin1 protein to promote glycolysis and cell stemness of TE1 and EC109 cells. Mutant Axin1 can inhibit ECAR, glucose uptake, lactate secretion, and cell stemness in TE1 and EC109 cells under normal or hypoxia conditions. Meanwhile, mutant Axin1 further enhanced the effects of 2-DG on inhibiting glycolysis and cell stemness. Overexpression of Axin1 also inhibited tumor growth in vivo, and was related to suppressing glycolysis. In conclusion, hypoxia treatment promoted the glycolysis and cell stemness of esophageal carcinoma cells, and increased the lactylation of Axin1 protein. Overexpression of Axin1 functioned as a glycolysis inhibitor, and suppressed the effects of hypoxia exposure in vitro and inhibited tumor growth in vivo. Mechanically, hypoxia induces the lactylation of Axin1 protein and promotes the ubiquitination of Axin1 to degrade the protein, thereby exercising its anti-glycolytic function.

Ferroptosis: principles and significance in health and disease

Ferroptosis, an iron-dependent form of cell death characterized by uncontrolled lipid peroxidation, is governed by molecular networks involving diverse molecules and organelles. Since its recognition as a non-apoptotic cell death pathway in 2012, ferroptosis has emerged as a crucial mechanism in numerous physiological and pathological contexts, leading to significant therapeutic advancements across a wide range of diseases. This review summarizes the fundamental molecular mechanisms and regulatory pathways underlying ferroptosis, including both GPX4-dependent and -independent antioxidant mechanisms. Additionally, we examine the involvement of ferroptosis in various pathological conditions, including cancer, neurodegenerative diseases, sepsis, ischemia-reperfusion injury, autoimmune disorders, and metabolic disorders. Specifically, we explore the role of ferroptosis in response to chemotherapy, radiotherapy, immunotherapy, nanotherapy, and targeted therapy. Furthermore, we discuss pharmacological strategies for modulating ferroptosis and potential biomarkers for monitoring this process. Lastly, we elucidate the interplay between ferroptosis and other forms of regulated cell death. Such insights hold promise for advancing our understanding of ferroptosis in the context of human health and disease.

Dichloroacetate for Cancer Treatment: Some Facts and Many Doubts

Rarely has a chemical elicited as much controversy as dichloroacetate (DCA). DCA was initially considered a dangerous toxic industrial waste product, then a potential treatment for lactic acidosis. However, the main controversies started in 2008 when DCA was found to have anti-cancer effects on experimental animals. These publications showed contradictory results in vivo and in vitro such that a thorough consideration of this compound's in cancer is merited. Despite 50 years of experimentation, DCA's future in therapeutics is uncertain. Without adequate clinical trials and health authorities' approval, DCA has been introduced in off-label cancer treatments in alternative medicine clinics in Canada, Germany, and other European countries. The lack of well-planned clinical trials and its use by people without medical training has discouraged consideration by the scientific community. There are few thorough clinical studies of DCA, and many publications are individual case reports. Case reports of DCA's benefits against cancer have been increasing recently. Furthermore, it has been shown that DCA synergizes with conventional treatments and other repurposable drugs. Beyond the classic DCA target, pyruvate dehydrogenase kinase, new target molecules have also been recently discovered. These findings have renewed interest in DCA. This paper explores whether existing evidence justifies further research on DCA for cancer treatment and it explores the role DCA may play in it.

Hypoxia-associated autophagy flux dysregulation in human cancers

A general feature of cancer is hypoxia, determined as low oxygen levels. Low oxygen levels may cause cells to alter in ways that contribute to tumor growth and resistance to treatment. Hypoxia leads to variations in cancer cell metabolism, angiogenesis and metastasis. Furthermore, a hypoxic tumor microenvironment might induce immunosuppression. Moreover, hypoxia has the potential to impact cellular processes, such as autophagy. Autophagy refers to the catabolic process by which damaged organelles and toxic macromolecules are broken down. The abnormal activation of autophagy has been extensively recorded in human tumors and it serves as a regulator of cell growth, spread to other parts of the body, and resistance to treatment. There is a correlation between hypoxia and autophagy in human malignancies. Hypoxia can regulate the activity of AMPK, mTOR, Beclin-1, and ATGs to govern autophagy in human malignancies. Furthermore, HIF-1α, serving as an indicator of low oxygen levels, controls the process of autophagy. Hypoxia-induced autophagy has a crucial role in regulating the growth, spread, and resistance to treatment in human malignancies. Hypoxia-induced regulation of autophagy can impact other mechanisms of cell death, such as apoptosis. Chemoresistance and radioresistance have become significant challenges in recent years. Hypoxia-mediated autophagy plays a crucial role in determining the response to these therapeutic treatments.