The interplay of the circadian clock and metabolic tumorigenesis

PCK1 inhibits cGAS-STING activation by consumption of GTP to promote tumor immune evasion

Hypoxia induces immunosuppressive phenotypes in tumor cells even in the presence of cytosolic DNA accumulation. The mechanisms by which tumor cells suppress hypoxia-induced cGAS-STING activation for immune evasion remain largely unclear. Here, we demonstrate that hypoxic stimulation induces JNK1/2-mediated S151 phosphorylation of phosphoenolpyruvate carboxykinase 1 (PCK1), a rate-limiting enzyme in gluconeogenesis. This phosphorylation triggers the interaction between PCK1 and cGAS. The PCK1 associated with cGAS competitively consumes GTP, a substrate shared by both PCK1 and cGAS. Consequently, PCK1 inhibits GTP-dependent cGAS activation and subsequent STING-promoted immune cell infiltration and activation in the tumor microenvironment, leading to promoted tumor growth in mice. The blockade of PCK1 function, in combination with anti-PD-1 antibody treatment, exhibits an additive therapeutic effect on tumor growth. Additionally, PCK1 S151 phosphorylation is inversely correlated with cGAS-STING activation in human breast cancer specimens and patient survival. These findings reveal a novel regulation of cGAS-STING pathway and uncover the metabolic control of immune response in tumor cells.

Integrating cancer medicine into metabolic rhythms

Circadian rhythms are cell-intrinsic time-keeping mechanisms that allow organisms to adapt to 24-h environmental changes, ensuring coordinated physiological functions by aligning internal metabolic oscillations with external timing cues. Disruption of daily metabolic rhythms is associated with pathological events such as cancer development, yet the mechanisms by which perturbed metabolic rhythms contribute to tumorigenesis remain unclear. Herein we review how circadian clocks drive balanced rhythmic metabolism which in turn governs physiological functions of locomotor, immune, and neuroendocrine systems. Misaligned metabolic rhythms cause pathological states which further drive cancer initiation, progression, and metastasis. Restoring the balance of metabolic rhythms with chemical, hormonal, and behavioral interventions serves as a promising strategy for cancer therapy.

Little strokes fell big oaks: The use of weak magnetic fields and reactive oxygen species to fight cancer

The increase in early-stage cancers, particularly gastrointestinal, breast and kidney cancers, has been linked to lifestyle changes such as consumption of processed foods and physical inactivity, which contribute to obesity and diabetes - major cancer risk factors. Conventional treatments such as chemotherapy and radiation often lead to severe long-term side effects, including secondary cancers and tissue damage, highlighting the need for new, safer and more effective therapies, especially for young patients. Weak electromagnetic fields (WEMF) offer a promising non-invasive approach to cancer treatment. While WEMF have been used therapeutically for musculoskeletal disorders for decades, their role in oncology is still emerging. WEMFs affect multiple cellular processes through mechanisms such as the radical pair mechanism (RPM), which alters reactive oxygen species (ROS) levels, mitochondrial function, and glycolysis, among others. This review explores the potential of WEMF in conjunction with reactive oxygen species as a cancer therapy, highlighting WEMFs selective targeting of cancer cells and its non-ionizing nature, which could reduce collateral damage compared to conventional treatments. In addition, synchronization of WEMF with circadian rhythms may further enhance its therapeutic efficacy, as has been demonstrated in other cancer therapies.

The role of circadian rhythm regulator PERs in oxidative stress, immunity, and cancer development

The complex interaction between circadian rhythms and physiological functions is essential for maintaining human health. At the heart of this interaction lies the PERIOD proteins (PERs), pivotal to the circadian clock, influencing the timing of physiological and behavioral processes and impacting oxidative stress, immune functionality, and tumorigenesis. PER1 orchestrates the cooperation of the enzyme GPX1, modulating mitochondrial dynamics in sync with daily rhythms and oxidative stress, thus regulating the mechanisms managing energy substrates. PERs in innate immune cells modulate the temporal patterns of NF-κB and TNF-α activities, as well as the response to LPS-induced toxic shock, initiating inflammatory responses that escalate into chronic inflammatory conditions. Crucially, PERs modulate cancer cell behaviors including proliferation, apoptosis, and migration by influencing the levels of cell cycle proteins and stimulating the expression of oncogenes c-Myc and MDM2. PER2/3, as antagonists in cancer stem cell biology, play important roles in differentiating cancer stem cells and in maintaining their stemness. Importantly, the expression of Pers serve as a significant factor for early cancer diagnosis and prognosis. This review delves into the link between circadian rhythm regulator PERs, disruptions in circadian rhythm, and oncogenesis. We examine the evidence that highlights how dysfunctions in PERs activities initiate cancer development, aid tumor growth, and modify cancer cell metabolism through pathways involved in oxidative stress and immune system. Comprehending these connections opens new pathways for the development of circadian rhythm-based therapeutic strategies, with the aims of boosting immune responses and enhancing cancer treatments.

Entry of ZSWIM4 to the nucleus is crucial for its inhibition of KIT and BMAL1 in gastrointestinal stromal tumors

BACKGROUND

Zinc finger SWIM-type containing 4 (ZSWIM4) is a zinc finger protein with its function largely uncharacterized. In this study, we aimed to investigate the role of ZSWIM4 in gastrointestinal stromal tumors (GISTs).

RESULTS

We found that ZSWIM4 expression is inhibited by the predominantly mutated protein KIT in GISTs, while conversely, ZSWIM4 inhibits KIT expression and downstream signaling. Consistent with the observation, ZSWIM4 inhibited GIST cell survival and proliferation in vitro. RNA sequencing of GISTs from KITV558A/WT mice and KITV558A/WT/ZSWIM4-/- mice showed that loss of ZSWIM4 expression increases the expression of circadian clock pathway member BMAL1 which contributes to GIST cell survival and proliferation. In addition, we found that KIT signaling increases the distribution of ZSWIM4 in the nucleus of GIST cells, and which is important for its inhibition of KIT and BMAL1. In agreement with the results in vitro, the in vivo studies showed that ZSWIM4 deficiency increases the tumorigenesis of GISTs in KITV558A/WT mice.

CONCLUSIONS

Taken together, our results revealed that the entry of ZSWIM4 to the nucleus is important for its inhibition of KIT and BMAL1, ultimately attenuating GIST tumorigenesis. The results provide a novel insight in the understanding of signal transduction in GISTs and lay strong theoretical basis for the advancement of GIST treatment.