Thymidine decreases the DNA damage and apoptosis caused by tumor-treating fields in cancer cell lines

Tumor-treating fields in cancer therapy: advances of cellular and molecular mechanisms

Tumor-Treating Fields (TTFields) use intermediate-frequency and low-intensity electric fields to inhibit tumor cells. However, their mechanisms are still not well understood. This article reviews their key antitumor mechanisms at the cellular and molecular levels, including inhibition of proliferation, induction of death, disturbance of migration, and activation of the immune system. The multifaceted biological effects in combination with other cancer treatments are also summarized. The deep insight into their mechanism will help develop more potential antitumor treatments.

Anti-cancer mechanisms of action of therapeutic alternating electric fields (tumor treating fields [TTFields])

Despite improved survival outcomes across many cancer types, the prognosis remains grim for certain solid organ cancers including glioblastoma and pancreatic cancer. Invariably in these cancers, the control achieved by time-limited interventions such as traditional surgical resection, radiation therapy, and chemotherapy is short-lived. A new form of anti-cancer therapy called therapeutic alternating electric fields (AEFs) or tumor treating fields (TTFields) has been shown, either by itself or in combination with chemotherapy, to have anti-cancer effects that translate to improved survival outcomes in patients. Although the pre-clinical and clinical data are promising, the mechanisms of TTFields are not fully elucidated. Many investigations are underway to better understand how and why TTFields is able to selectively kill cancer cells and impede their proliferation. The purpose of this review is to summarize and discuss the reported mechanisms of action of TTFields from pre-clinical studies (both in vitro and in vivo). An improved understanding of how TTFields works will guide strategies focused on the timing and combination of TTFields with other therapies, to further improve survival outcomes in patients with solid organ cancers.

NAPRT, but Not NAMPT, Provides Additional Support for NAD Synthesis in Esophageal Precancerous Lesions

It is hypothesized that esophageal precancerous lesions (EPLs) have a surge requirement for coenzyme I (NAD). The purpose of this study is to clarify the key control points of NAD synthesis in developing EPL by detecting related markers and the gene polymorphism of NAD synthesis and metabolism. This case-control study was conducted in Huai'an, China. In total, 100 healthy controls and 100 EPL cases matched by villages, gender, and age (±2 years) were included. The levels of plasma niacin and nicotinamide, and the protein concentration of NAMPT, NAPRT, and PARP-1 were quantitatively analyzed. PARP-1 gene polymorphism was detected to determine if the cases differed genetically in NAD synthesis. The levels of plasma niacin and nicotinamide and the concentrations of NAMPT were not related to the risk of EPL, but the over-expressions of NAPRT (p = 0.014, 0.001, and 0.016, respectively) and PARP-1 (p for trend = 0.021) were associated with the increased EPL risk. The frequency distribution of APRP-1 genotypes was found to not differ between the two groups, while the EPL group showed an increased frequency of the variant C allele. NAPRT, but not NAMPT, was found to be responsible for the stress of excess NAD synthesis in EPL. Focusing on the development of NAPRT inhibitors may be beneficial to prevent and control ESCC.

The schemes, mechanisms and molecular pathway changes of Tumor Treating Fields (TTFields) alone or in combination with radiotherapy and chemotherapy

Tumor Treating Fields (TTFields) is a physical therapy that uses moderate frequency (100-300 kHz) and low-intensity (1-3 V/cm) alternating electric fields to inhibit tumors. Currently, the Food and Drug Administration approves TTFields for treating recurrent or newly diagnosed glioblastoma (GBM) and malignant pleural mesothelioma (MPM). The classical mechanism of TTFields is mitotic inhibition by hindering the formation of tubulin and spindle. In addition, TTFields inhibits cell proliferation, invasion, migration and induces cell death, such as apoptosis, autophagy, pyroptosis, and cell cycle arrest. Meanwhile, it regulates immune function and changes the permeability of the nuclear membrane, cell membrane, and blood-brain barrier. Based on the current researches on TTFields in various tumors, this review comprehensively summarizes the in-vitro effects, changes in pathways and molecules corresponding to relevant parameters of TTFields (frequency, intensity, and duration). In addition, radiotherapy and chemotherapy are common tumor treatments. Thus, we also pay attention to the sequence and dose when TTFields combined with radiotherapy or chemotherapy. TTFields has inhibitory effects in a variety of tumors. The study of TTFields mechanism is conducive to subsequent research. How to combine common tumor therapy such as radiotherapy and chemotherapy to obtain the maximum benefit is also a problem that's worthy of our attention.