Nuclear Transport Factor 2 (NTF2) suppresses WM983B metastatic melanoma by modifying cell migration, metastasis, and gene expression

Nuclear growth and import can be uncoupled

What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while import is required for nuclear growth, nuclear growth and import can be uncoupled when chromatin structure is manipulated. Nuclei treated with micrococcal nuclease to fragment DNA grew slowly despite exhibiting little to no change in import rates. Nuclei assembled around axolotl chromatin with 20-fold more DNA than Xenopus grew larger but imported more slowly. Treating nuclei with reagents known to alter histone methylation or acetylation caused nuclei to grow less while still importing to a similar extent or to grow larger without significantly increasing import. Nuclear growth but not import was increased in live sea urchin embryos treated with the DNA methylator N-nitrosodimethylamine. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, we observed that nuclear blebs expanded preferentially at sites of high chromatin density and lamin addition, whereas small Benzonase-treated nuclei lacking DNA exhibited reduced lamin incorporation into the nuclear envelope. In summary, we report experimental conditions where nuclear import is not sufficient to drive nuclear growth, hypothesizing that this uncoupling is a result of altered chromatin structure.

Native top-down proteomics reveals EGFR-ERα signaling crosstalk in breast cancer cells dissociates NUTF2 dimers to modulate ERα signaling and cell growth

Oligomerization of proteins and their modified forms (proteoforms) produces functional protein complexes 1,2. Complexoforms are complexes that consist of the same set of proteins with different proteoforms 3. The ability to characterize these assemblies within cells is critical to understanding the molecular mechanisms involved in disease and to designing effective drugs. An outstanding biological question is how proteoforms drive function and oligomerization of complexoforms. However, tools to define endogenous proteoform-proteoform/ligand interactions are scarce 4. Here, we present a native top-down proteomics (nTDP) strategy that combines size-exclusion chromatography, nano liquid-chromatography in direct infusion mode, field asymmetric ion mobility spectrometry, and multistage mass spectrometry to identify protein assemblies (≤70 kDa) in breast cancer cells and in cells that overexpress EGFR, a resistance model of estrogen receptor-α (ER-α) targeted therapies. By identifying ~104 complexoforms from 17 protein complexes, our nTDP approach revealed several molecular features of the breast cancer proteome, including EGFR-induced dissociation of nuclear transport factor 2 (NUTF2) assemblies that modulate ER activity. Our findings show that the K4 and K55 posttranslational modification sites discovered with nTDP differentially impact the effects of NUTF2 on the inhibition of the ER signaling pathway. By characterizing endogenous proteoform-proteoform/ligand interactions, we reveal the molecular diversity of complexoforms, which allows us to propose a model for ER drug discovery in the context of designing effective inhibitors to selectively bind and disrupt the actions of targeted ER complexoforms.

The biological significance of cuproptosis-key gene MTF1 in pan-cancer and its inhibitory effects on ROS-mediated cell death of liver hepatocellular carcinoma

Metal regulatory transcription factor 1 (MTF1) has been reported to be correlated with several human diseases, especially like cancers. Exploring the underlying mechanisms and biological functions of MTF1 could provide novel strategies for clinical diagnosis and therapy of cancers. In this study, we conducted the comprehensive analysis to evaluate the profiles of MTF1 in pan-cancer. For example, TIMER2.0, TNMplot and GEPIA2.0 were employed to analyze the expression values of MTF1 in pan-cancer. The methylation levels of MTF1 were evaluated via UALCAN and DiseaseMeth version 2.0 databases. The mutation profiles of MTF1 in pan-cancers were analyzed using cBioPortal. GEPIA2.0, Kaplan-Meier plotter and cBioPortal were also used to explore the roles of MTF1 in cancer prognosis. We found that high MTF1 expression was related to poor prognosis of liver hepatocellular carcinoma (LIHC) and brain lower grade glioma (LGG). Also, high expression level of MTF1 was associated with good prognosis of kidney renal clear cell carcinoma (KIRC), lung cancer, ovarian cancer and breast cancer. We investigated the genetic alteration and methylation levels of MTF1 between the primary tumor and normal tissues. The relationship between MTF1 expression and several immune cells was analyzed, including T cell CD8 + and dendritic cells (DC). Mechanically, MTF1-interacted molecules might participate in the regulation of metabolism-related pathways, such as peptidyl-serine phosphorylation, negative regulation of cellular amide metabolic process and peptidyl-threonine phosphorylation. Single cell sequencing indicated that MTF1 was associated with angiogenesis, DNA repair and cell invasion. In addition, in vitro experiment indicated knockdown of MTF1 resulted in the suppressed cell proliferation, increased reactive oxygen species (ROS) and promoted cell death in LIHC cells HepG2 and Huh7. Taken together, this pan-cancer analysis of MTF1 has implicated that MTF1 could play an essential role in the progression of various human cancers.

Nuclear growth and import can be uncoupled

What drives nuclear growth? Studying nuclei assembled in Xenopus egg extract and focusing on importin α/β-mediated nuclear import, we show that, while nuclear growth depends on nuclear import, nuclear growth and import can be uncoupled. Nuclei containing fragmented DNA grew slowly despite exhibiting normal import rates, suggesting nuclear import itself is insufficient to drive nuclear growth. Nuclei containing more DNA grew larger but imported more slowly. Altering chromatin modifications caused nuclei to grow less while still importing to the same extent or to grow larger without increasing nuclear import. Increasing heterochromatin in vivo in sea urchin embryos increased nuclear growth but not import. These data suggest that nuclear import is not the primary driving force for nuclear growth. Instead, live imaging showed that nuclear growth preferentially occurred at sites of high chromatin density and lamin addition, whereas small nuclei lacking DNA exhibited less lamin incorporation. Our hypothesized model is that lamin incorporation and nuclear growth are driven by chromatin mechanical properties, which depend on and can be tuned by nuclear import.

Epidemiology, management, and treatment outcomes of metastatic spinal melanoma

Metastatic spinal melanoma is a rare and aggressive disease process with poor prognosis. We review the literature on metastatic spinal melanoma, focusing on its epidemiology, management, and treatment outcomes. Demographics of metastatic spinal melanoma are similar to those for cutaneous melanoma, and cutaneous primary tumors tend to be most common. Decompressive surgical intervention and radiotherapy have traditionally been considered mainstays of treatment, and stereotactic radiosurgery has emerged as a promising approach in the operative management of metastatic spinal melanoma. While survival outcomes for metastatic spinal melanoma remain poor, they have improved in recent years with the advent of immune checkpoint inhibition, used in conjunction with surgery and radiotherapy. New treatment options remain under investigation, especially for patients with disease refractory to immunotherapy. We additionally explore several of these promising future directions. Nevertheless, further investigation of treatment outcomes, ideally incorporating high-quality prospective data from randomized controlled trials, is needed to identify optimal management of metastatic spinal melanoma.

Regulation of organelle size and organization during development

During early embryogenesis, as cells divide in the developing embryo, the size of intracellular organelles generally decreases to scale with the decrease in overall cell size. Organelle size scaling is thought to be important to establish and maintain proper cellular function, and defective scaling may lead to impaired development and disease. However, how the cell regulates organelle size and organization are largely unanswered questions. In this review, we summarize the process of size scaling at both the cell and organelle levels and discuss recently discovered mechanisms that regulate this process during early embryogenesis. In addition, we describe how some recently developed techniques and Xenopus as an animal model can be used to investigate the underlying mechanisms of size regulation and to uncover the significance of proper organelle size scaling and organization.