Cytoplasmic Localization Isoform of Cyclin Y Enhanced the Metastatic Ability of Lung Cancer via Regulating Tropomyosin 4

Cyclin Y interacts with Chk1 to activate RRM2/STAT3 signaling and promotes radioresistance in non-small cell lung cancer

Radioresistance is one of the main reasons for the recurrence and metastasis of non-small cell lung cancer. Cyclin Y has been implicated in various cellular processes such as cell growth, proliferation, autophagy, and tumor progression. However, the function and regulatory mechanism of Cyclin Y in lung cancer radioresistance remain poorly understood. In this study, we find that Cyclin Y is overexpressed in non-small cell lung cancer and correlates with poor prognosis. Furthermore, knockdown of Cyclin Y results in inhibited cell growth and proliferation, increases DNA damage, impairs DNA damage repair, and enhances radiosensitivity in vitro and in vivo. Mechanistically, we uncover that Cyclin Y interacts with Chk1 and positively regulate both the mRNA and protein levels of RRM2, resulting in increased STAT3 phosphorylation. Rescue experiments confirm that the effects of Cyclin Y on lung cancer are mediated partially by RRM2. Collectively, we reveal for the first time that Cyclin Y promotes lung cancer radioresistance by binding to Chk1 to activate RRM2/STAT3 signaling, indicating that targeting Cyclin Y may be a promising strategy for enhancing the efficacy of radiotherapy in the treatment of non-small cell lung cancer.

Methylation-modulated PFTK1 regulates gefitinib resistance via Wnt/β-catenin signaling in EGFR mutant non-small-cell lung cancer cells

Inevitable gefitinib resistance is the biggest bottleneck in current treatment and the mechanisms are not fully understood. Here, we observe that PFTK1 (also named CDK14) is significantly enhanced in NSCLC with gefitinib resistance. And the upregulation of PFTK1 is negatively associated with progression-free survival (PFS) in NSCLC patients who receive gefitinib treatment. Further study suggests that gefitinib can critically accelerate PFTK1 through suppressing its promoter methylation in a DNMT3B-dependent manner. Gain and loss of function assays demonstrate that desregulation of PFTK1 significantly enhances gefitinib resistance in NSCLC. PFTK1 interacts with LRP6 and activates Wnt/β-catenin signaling to attenuate gefitinib-induced cellular apoptosis. Moreover, FMF-04-159-2, a specific covalent inhibitor of PFTK1, can reverse the effect of PFTK1 on gefitinib resistance in vitro and in vivo. Consequently, these findings shed new light on the mechanism underlying gefitinib resistance, and suggest PFTK1 as a target for gefitinib treatment in NSCLC.

Research Advances in the Role of the Tropomyosin Family in Cancer

Cancer is one of the most difficult diseases for human beings to overcome. Its development is closely related to a variety of factors, and its specific mechanisms have been a hot research topic in the field of scientific research. The tropomyosin family (Tpm) is a group of proteins closely related to the cytoskeleton and actin, and recent studies have shown that they play an important role in various cancers, participating in a variety of biological activities, including cell proliferation, invasion, and migration, and have been used as biomarkers for various cancers. The purpose of this review is to explore the research progress of the Tpm family in tumorigenesis development, focusing on the molecular pathways associated with them and their relevant activities involved in tumors. PubMed and Web of Science databases were searched for relevant studies on the role of Tpms in tumorigenesis and development and the activities of Tpms involved in tumors. Data from the literature suggest that the Tpm family is involved in tumor cell proliferation and growth, tumor cell invasion and migration, tumor angiogenesis, tumor cell apoptosis, and immune infiltration of the tumor microenvironment, among other correlations. It can be used as a potential biomarker for early diagnosis, follow-up, and therapeutic response of some tumors. The Tpm family is involved in cancer in a close relationship with miRNAs and LncRNAs. Tpms are involved in tumor tissue invasion and migration as a key link. On this basis, TPM is frequently used as a biomarker for various cancers. However, the specific molecular mechanism of its involvement in cancer progression has not been explained clearly, which remains an important direction for future research.

Cytoskeleton remodeling mediated by circRNA-YBX1 phase separation suppresses the metastasis of liver cancer

Metastasis, especially intrahepatic, is a major challenge for hepatocellular carcinoma (HCC) treatment. Cytoskeleton remodeling has been identified as a vital process mediating intrahepatic spreading. Previously, we reported that HCC tumor adhesion and invasion were modulated by circular RNA (circRNA), which has emerged as an important regulator of various cellular processes and has been implicated in cancer progression. Here, we uncovered a nuclear circRNA, circASH2, which is preferentially lost in HCC tissues and inhibits HCC metastasis by altering tumor cytoskeleton structure. Tropomyosin 4 (TPM4), a critical binding protein of actin, turned out to be the major target of circASH2 and was posttranscriptionally suppressed. Such regulation is based on messenger RNA (mRNA)/precursormRNA splicing and degradation process. Furthermore, liquid-liquid phase separation of nuclear Y-box binding protein 1 (YBX1) enhanced by circASH2 augments TPM4 transcripts decay. Together, our data have revealed a tumor-suppressive circRNA and, more importantly, uncovered a fine regulation mechanism for HCC progression.

The role of cyclin Y in normal and pathological cells

The family protein of cyclins, as well as cyclin-dependent kinases (CDKs) cooperating with them, are broadly researched, as a matter of their dysfunction may lead to tumor transformation. Cyclins are defined as key regulators that have a controlling function of the mammalian nuclear cell divides. Cyclin Y (CCNY) is a recently characterized member of the cyclin family and was first identified from the human testis cDNA library. It is an actin-binding protein acting through decreased actin dynamics at a steady state and during glycine-induced long-term potentiation (LTP) and involves the inhibition of cofilin activation. What is more, CCNY is a positive regulatory subunit of the CDK14/PFTK1 complexes affected by the activation of the Wnt signaling pathway in the G2/M phase by recruiting CDK14/PFTK1 to the plasma membrane and promoting phosphorylation of LRP6. The expression of CCNY has been significantly mentioned within the cell migration and invasion activity both in vivo and in vitro. The aim of this review is evaluation of the expression of CCNY in the physiology processes and compare the expression of this protein in cancer cells, taking into account the impact of the level of expression on tumor progression.