bims-ectoca 2024-02-18 papers

Issue of 2024‒02‒18
four papers selected by
Ankita Daiya, BITS Pilani

Mol Oncol. 2024 Feb 15.

TPX2 overexpression promotes sensitivity to dasatinib in breast cancer by activating YAP transcriptional signaling.

Carlos Marugán, Natalia Sanz-Gómez, Beatriz Ortigosa, Ana Monfort-Vengut, Cristina Bertinetti, Ana Teijo, Marta González, Alicia Alonso de la Vega, María José Lallena, Gema Moreno-Bueno, Guillermo de Cárcer.

Chromosomal instability (CIN) is a hallmark of cancer aggressiveness, providing genetic plasticity and tumor heterogeneity that allows the tumor to evolve and adapt to stress conditions. CIN is considered a cancer therapeutic biomarker because healthy cells do not exhibit CIN. Despite recent efforts to identify therapeutic strategies related to CIN, the results obtained have been very limited. CIN is characterized by a genetic signature where a collection of genes, mostly mitotic regulators, are overexpressed in CIN-positive tumors, providing aggressiveness and poor prognosis. We attempted to identify new therapeutic strategies related to CIN genes by performing a drug screen, using cells that individually express CIN-associated genes in an inducible manner. We find that the overexpression of targeting protein for Xklp2 (TPX2) enhances sensitivity to the proto-oncogene c-Src (SRC) inhibitor dasatinib due to activation of the Yes-associated protein 1 (YAP) pathway. Furthermore, using breast cancer data from The Cancer Genome Atlas (TCGA) and a cohort of cancer-derived patient samples, we find that both TPX2 overexpression and YAP activation are present in a significant percentage of cancer tumor samples and are associated with poor prognosis; therefore, they are putative biomarkers for selection for dasatinib therapy.

Keywords: Hippo-YAP/TAZ; SFK kinases; TPX2; chromosomal instability; dasatinib; mitosis

DOI: https://doi.org/10.1002/1878-0261.13602

J Cancer. 2024 ;15(5): 1287-1298

Lnc-CLSTN2-1:1 Promotes Osteosarcoma Progression by Disrupting Redox Balance through PI3K/AKT Signaling Pathway.

Hao Lin, Xinjian Wei, Junhong Ye, Jiaxian Chen, Jing Huang, Tingrui Wu, Zhenju Chen, Yuming Zeng, Lijiao Peng.

Objective: Most patients with osteosarcoma (OS) have an extremely poor prognosis. The primary purpose of this investigation was to explore the biological effect of Lnc-CLSTN2-1:1 on OS and the potential processes involved. Materials and procedures: We selected differentially overexpressed Lnc-CLSTN2-1:1 from our laboratory's existing RNA sequence analysis data (fibroblast osteoblast (hFOB 1.19) and three osteosarcoma cell lines (HOS, MG63, and U2OS) as the research object. Next, we detected Lnc-CLSTN2-1:1 in the osteosarcoma HOS cell line and fibroblast cells using qRT-PCR. We evaluated cell proliferation ability using EdU incorporation test, CCK-8 test, and cell clone formation; cell invasion and migration were assessed using the Transwell test, while flow cytometry examined cell cycle, apoptosis, and reactive oxygen species (ROS); Subsequently, the activity changes of selenase (GPx) glutathione peroxidase and (TrxR) thioredoxin reductase were detected. In addition, changes in related proteins were analyzed through Western blotting. Results: The expression of Lnc-CLSTN2-1:1 in osteosarcoma cells was significantly increased. The proliferation, invasion, and migration of osteosarcoma cells were significantly inhibited by knockdown of the expression of Lnc-CLSTN2-1:1, and the cell cycle-related signaling pathway PI3K/AKT/GSK-3β/cycinD1 was also inhibited. However, insulin-like growth factor-1 (igf-1) could reverse this process. In addition, we examined the activity of two selenophenases (TrxR and GPx) and the changes of ROS before and after Lnc-CLSTN2-1:1 knockdown. The results showed that both TrxR and GPx activities were reduced after Lnc-CLSTN2-1:1 knockdown, resulting in the inhibition of antioxidant stress levels, while intracellular ROS levels were high, which eventually caused killing effects on tumor cells due to the imbalance between oxidative stress and antioxidant stress. Conclusion: Our results showed that Lnc-CLSTN2-1:1 enhanced anti-oxidative stress TrxR and GPx selenoprotein activities through the PI3K/AKT signaling pathway while counteracting the loss of reactive oxygen species ROS produced by mitochondria to osteosarcoma cells, which protected osteosarcoma cells and thus promoted the proliferation and metastatic ability of OS.

Keywords: GPx; ROS; TrxR; long non-coding RNA; osteosarcoma

DOI: https://doi.org/10.7150/jca.91579

J Cell Biochem. 2024 Feb 12.

Mechanotransduction and epigenetic modulations of chromatin: Role of mechanical signals in gene regulation.

Jagdish Mishra, Subhajit Chakraborty, Niharika, Ankan Roy, Soumen Manna, Tirthankar Baral, Piyasa Nandi, Samir K Patra.

Mechanical forces may be generated within a cell due to tissue stiffness, cytoskeletal reorganization, and the changes (even subtle) in the cell's physical surroundings. These changes of forces impose a mechanical tension within the intracellular protein network (both cytosolic and nuclear). Mechanical tension could be released by a series of protein-protein interactions often facilitated by membrane lipids, lectins and sugar molecules and thus generate a type of signal to drive cellular processes, including cell differentiation, polarity, growth, adhesion, movement, and survival. Recent experimental data have accentuated the molecular mechanism of this mechanical signal transduction pathway, dubbed mechanotransduction. Mechanosensitive proteins in the cell's plasma membrane discern the physical forces and channel the information to the cell interior. Cells respond to the message by altering their cytoskeletal arrangement and directly transmitting the signal to the nucleus through the connection of the cytoskeleton and nucleoskeleton before the information despatched to the nucleus by biochemical signaling pathways. Nuclear transmission of the force leads to the activation of chromatin modifiers and modulation of the epigenetic landscape, inducing chromatin reorganization and gene expression regulation; by the time chemical messengers (transcription factors) arrive into the nucleus. While significant research has been done on the role of mechanotransduction in tumor development and cancer progression/metastasis, the mechanistic basis of force-activated carcinogenesis is still enigmatic. Here, in this review, we have discussed the various cues and molecular connections to better comprehend the cellular mechanotransduction pathway, and we also explored the detailed role of some of the multiple players (proteins and macromolecular complexes) involved in mechanotransduction. Thus, we have described an avenue: how mechanical stress directs the epigenetic modifiers to modulate the epigenome of the cells and how aberrant stress leads to the cancer phenotype.

Keywords: ECM; cancer; chromatin; cytoskeleton; epigenetics; mechanotransduction; nucleoskeleton

DOI: https://doi.org/10.1002/jcb.30531

Nucleic Acids Res. 2024 Feb 16. pii: gkae119. [Epub ahead of print]

Mor Angel, Eden Fleshler, Mohammad Khaled Atrash, Noa Kinor, Jennifer I C Benichou, Yaron Shav-Tal.

Stress granules (SGs) are cytoplasmic assemblies formed under various stress conditions as a consequence of translation arrest. SGs contain RNA-binding proteins, ribosomal subunits and messenger RNAs (mRNAs). It is well known that mRNAs contribute to SG formation; however, the connection between SG assembly and nuclear processes that involve mRNAs is not well established. Here, we examine the effects of inhibiting mRNA transcription, splicing and export on the assembly of SGs and the related cytoplasmic P body (PB). We demonstrate that inhibition of mRNA transcription, splicing and export reduces the formation of canonical SGs in a eukaryotic initiation factor 2α phosphorylation-independent manner, and alters PB size and quantity. We find that the splicing inhibitor madrasin promotes the assembly of stress-like granules. We show that the addition of synthetic mRNAs directly to the cytoplasm is sufficient for SG assembly, and that the assembly of these SGs requires the activation of stress-associated protein synthesis pathways. Moreover, we show that adding an excess of mRNA to cells that do not have active splicing, and therefore have low levels of cytoplasmic mRNAs, promotes SG formation under stress conditions. These findings emphasize the importance of the cytoplasmic abundance of newly transcribed mRNAs in the assembly of SGs.

DOI: https://doi.org/10.1093/nar/gkae119