CUX1 Enhances Pancreatic Cancer Formation by Synergizing with KRAS and Inducing MEK/ERK-Dependent Proliferation

FRA1 controls acinar cell plasticity during murine KrasG12D-induced pancreatic acinar to ductal metaplasia

Acinar cells have been proposed as a cell-of-origin for pancreatic ductal adenocarcinoma (PDAC) after undergoing acinar-to-ductal metaplasia (ADM). ADM can be triggered by pancreatitis, causing acinar cells to de-differentiate to a ductal-like state. We identify FRA1 (gene name Fosl1) as the most active transcription factor during KrasG12D acute pancreatitis-mediated injury, and we have elucidated a functional role of FRA1 by generating an acinar-specific Fosl1 knockout mouse expressing KrasG12D. Using a gene regulatory network and pseudotime trajectory inferred from single-nuclei ATAC-seq and bulk RNA sequencing (RNA-seq), we hypothesized a regulatory model of the acinar-ADM-pancreatic intraepithelial neoplasia (PanIN) continuum and experimentally validated that Fosl1 knockout mice are delayed in the onset of ADM and neoplastic transformation. Our study also identifies that pro-inflammatory cytokines, such as granulocyte colony stimulating factor (G-CSF), can regulate FRA1 activity to modulate ADM. Our findings identify that FRA1 is a mediator of acinar cell plasticity and is critical for acinar cell de-differentiation and transformation.

p110CUX1 promotes acute myeloid leukemia progression via regulating pyridoxal phosphatase expression and activating PI3K/AKT/mTOR signaling pathway

As an evolutionarily conserved transcription factor, Cut-like homeobox 1 (CUX1) plays crucial roles in embryonic and nervous system development, cell differentiation, and DNA damage repair. One of its major isoforms, p110CUX1, exhibits stable DNA binding capabilities and contributes to the regulation of cell cycle progression, proliferation, migration, and invasion. While p110CUX1 has been implicated in the progression of various malignant tumors, its involvement in acute myeloid leukemia (AML) remains uncertain. This study aims to elucidate the role of p110CUX1 in AML. Our findings reveal heightened expression levels of both p110CUX1 and pyridoxal phosphatase (PDXP) in AML cell lines. Overexpression of p110CUX1 promotes AML cell proliferation while inhibiting apoptosis and differentiation, whereas knockdown of PDXP yields contrasting effects. Mechanistically, p110CUX1 appears to facilitate AML development by upregulating PDXP expression and activating the PI3K/AKT/mTOR signaling pathway. Animal experimental corroborate the pro-AML effect of p110CUX1. These results provide experimental evidence supporting the involvement of the p110CUX1-PDXP-PI3K/AKT/mTOR axis in AML progression. Hence, targeting p110CUX1 may hold promise as a therapeutic strategy for AML.

B3GNT5 is a novel marker correlated with malignant phenotype and poor outcome in pancreatic cancer

Pancreatic cancer (PC) is one of the most lethal malignancies and new therapeutic strategies are urgently needed. β1,3-N-acetylglucosaminyltransferase V (B3GNT5) may be a potential option for cancer treatment, but its role in PC remains unknown. In this study, we first demonstrated through bioinformatics analysis that B3GNT5 was high expression in PC and predicted poor prognosis. We further constructed B3GNT5 overexpression or knockdown cell lines by employing lentivirus packaging techniques and confirmed that B3GNT5 could promote tumor cell viability and autonomous growth using cultured cells and vivo xenograft models. In addition, we found that knockdown of B3GNT5 in PC cells inhibited cell migration, invasion, and angiogenesis, as well as stemness of cancer stem cells and enhanced chemotherapy sensitivity to gemcitabine. Mechanistically, overexpression of the transcription factor STAT5B in PC cells enhanced the transcriptional activity of the B3GNT5 promoter. Our work confirmed a tumor-promotive role of B3GNT5 in PC pathogenesis.

CUX1 attenuates the apoptosis of renal tubular epithelial cells induced by contrast media through activating the PI3K/AKT signaling pathway

OBJECTIVE

Contrast media (CM) is a commonly applied drug in medical examination and surgery. However, contrast-induced acute kidney injury (CIAKI) poses a severe threat to human life and health. Notably, the CUT-like homeobox 1 (CUX1) gene shows protective effects in a variety of cells. Therefore, the objective of this study was to provide a new target for the treatment of CIAKI through exploring the role and possible molecular mechanism of CUX1 in CIAKI.

METHOD

Blood samples were collected from 20 patients with CIAKI and healthy volunteers. Human kidney 2 (HK-2) cells were incubated with 200 mg/mL iohexol for 6 h to establish a contrast-induced injury model of HK-2 cells. Subsequently, qRT-PCR was used to detect the relative mRNA expression of CUX1; CCK-8 and flow cytometry to assess the proliferation and apoptosis of HK-2 cells; the levels of IL(interleukin)-1β, tumor necrosis factor alpha (TNF-α) and malondialdehyde (MDA) in cells and lactate dehydrogenase (LDH) activity in cell culture supernatant were detect; and western blot to observe the expression levels of CUX1 and the PI3K/AKT signaling pathway related proteins [phosphorylated phosphoinositide 3-kinase (p-PI3K), PI3K, phosphorylated Akt (p-AKT), AKT].

RESULTS

CUX1 expression was significantly downregulated in blood samples of patients with CIAKI and contrast-induced HK-2 cells. Contrast media (CM; iohexol) treatment significantly reduced the proliferation of HK-2 cells, promoted apoptosis, stimulated inflammation and oxidative stress that caused cell damage. CUX1 overexpression alleviated cell damage by significantly improving the proliferation level of HK-2 cells induced by CM, inhibiting cell apoptosis, and reducing the level of LDH in culture supernatant and the expression of IL-1β, TNF-α and MDA in cells. CM treatment significantly inhibited the activity of PI3K/AKT signaling pathway activity. Nevertheless, up-regulating CUX1 could activate the PI3K/AKT signaling pathway activity in HK-2 cells induced by CM.

CONCLUSION

CUX1 promotes cell proliferation, inhibits apoptosis, and reduces inflammation and oxidative stress in CM-induced HK-2 cells to alleviate CM-induced damage. The mechanism of CUX1 may be correlated with activation of the PI3K/AKT signaling pathway.

p200CUX1-regulated BMP8B inhibits the progression of acute myeloid leukemia via the MAPK signaling pathway

The full-length p200CUX1 protein encoded by the homology frame CUT-like protein (CUX1) plays an important role in tumors as a pro-oncogene or oncogene. However, its role and mechanism in acute myeloid leukemia remain unknown. p200CUX1 regulates several pathways, including the MAPK signaling pathway. Our data showed that p200CUX1 is lowly expressed in THP1 and U937 AML cell lines. Lentiviral overexpression of p200CUX1 reduced proliferation and promoted apoptosis and G0/G1 phase blockade, correlating with MAPK pathway suppression. Additionally, p200CUX1 regulated the expression of bone morphogenetic protein 8B (BMP8B), which is overexpressed in AML. Overexpression of p200CUX1 downregulated BMP8B expression and inhibited the MAPK pathway. Furthermore, BMP8B knockdown inhibited AML cell proliferation, enhanced apoptosis and the sensitivity of ATRA-induced cell differentiation, and blocked G0/G1 transition. Our findings demonstrate the pivotal function of the p200CUX1-BMP8B-MAPK axis in maintaining the viability of AML cells. Consequently, targeting p200CUX1 could represent a viable strategy in AML therapy.

GABRP Promotes the Metastasis of Pancreatic Cancer by Activation of the MEK/ERK Signaling Pathway

Pancreatic cancer remains the common cancer with the worst prognosis because of its late diagnosis and extensive metastasis. This study aimed to investigate the effects of GABRP on pancreatic cancer metastasis and the molecular mechanism. The expression of GABRP was measured using the quantitative real-time PCR and western blot. The biological behaviors of cancer cells were assessed using the cell counting kit-8, Transwell assay, and western blot. The regulation of GABRP on the MEK/ERK pathway was detected by western blot. The results indicated that GABRP was overexpressed in pancreatic cancer tissues and cells. Knockdown of GABRP suppressed cell viability, invasion, migration, and epithelial-mesenchymal transition (EMT), whereas GABRP overexpression facilitated these biological behaviors. Inactivation of the MEK/ERK pathway reversed the effects on cellular processes induced by GABRP. Moreover, silencing of GABRP inhibited tumor growth. In conclusion, GABRP promoted the progression of pancreatic cancer by facilitating cell metastasis and tumor growth via activating the MEK/ERK pathway. The findings suggest that GABRP has the potential to be a therapeutic target for the metastatic pancreatic cancer.

Cut homeodomain transcription factor is a novel regulator of growth and morphogenesis of cortex glia niche around neural cells

Cortex glia in Drosophila central nervous system form a niche around neural cells for necessary signals to establish cross talk with their surroundings. These cells grow and expand their thin processes around neural cell bodies. Although essential for the development and function of the nervous system, how these cells make extensive and intricate connected networks remains largely unknown. In this study, we show that Cut, a homeodomain transcription factor, directly regulates the fate of the cortex glia, impacting neural stem cell (NSC) homeostasis. Focusing on the thoracic ventral nerve cord, we found that Cut is required for the normal growth and development of cortex glia and timely increase in DNA content through endocycle to later divide via acytokinetic mitosis. Knockdown of Cut in cortex glia significantly reduces the growth of cellular processes, the network around NSCs, and their progeny's cell bodies. Conversely, overexpression of Cut induces overall growth of the main processes at the expense of side ones. Whereas the Cut knockdown slows down the timely increase of DNA, the Cut overexpression results in a significant increase in nuclear size and volume and a 3-fold increase in DNA content of cortex glia. Further, we note that constitutively high Cut also interfered with nuclei separation during acytokinetic mitosis. Since the cortex glia form syncytial networks around neural cells, the finding identifies Cut as a novel regulator of glial growth and variant cell cycles to support a functional nervous system.

Molecular subtyping and characterization of clear cell renal cell carcinoma by tumor differentiation trajectories

Previous bulk RNA sequencing or whole genome sequencing on clear cell renal cell carcinoma (ccRCC) subtyping mainly focused on ccRCC cell origin or the complex tumor microenvironment (TME). Based on the single-cell RNA sequencing (scRNA-seq) data of 11 primary ccRCC specimens, cancer stem-cell-like subsets could be differentiated into five trajectories, whereby we further classified ccRCC cells into three groups with diverse molecular features. These three ccRCC subgroups showed significantly different outcomes and potential targets to tyrosine kinase inhibitors (TKIs) or immune checkpoint inhibitors (ICIs). Tumor cells in three differentiation directions exhibited distinct interactions with other subsets in the ccRCC niches. The subtyping model was examined through immunohistochemistry staining in our ccRCC cohort and validated the same classification effect as the public patients. All these findings help gain a deeper understanding about the pathogenesis of ccRCC and provide useful clues for optimizing therapeutic schemes based on the molecular subtype analysis.

Activation of ERK1/2 by MOS and TPL2 leads to dasatinib resistance in chronic myeloid leukaemia cells

The development of BCR::ABL1 tyrosine kinase inhibitors (TKIs), such as dasatinib, has dramatically improved survival in cases of chronic myeloid leukaemia (CML). However, the development of resistance to BCR::ABL1 TKIs is a clinical problem. BCR::ABL1 TKI resistance is known to have BCR::ABL1-dependent or BCR::ABL1-independent mechanisms, but the mechanism of BCR::ABL1 independence is not well understood. In the present study, we investigated the mechanism of BCR::ABL1-independent dasatinib resistance. The expression and activation level of genes or proteins were evaluated using array CGH, real time PCR, or western blot analysis. Gene expression was modulated using siRNA-mediated knockdown. Cell survival was assessed by using trypan blue dye method. We found that dasatinib-resistant K562/DR and KU812/DR cells did not harbour a BCR::ABL1 mutation but had elevated expression and/or activation of MOS, TPL2 and ERK1/2. In addition, MOS siRNA, TPL2 siRNA and trametinib resensitized dasatinib-resistant cells to dasatinib. Moreover, expression levels of MOS in dasatinib non-responder patients with CML were higher than those in dasatinib responders, and the expression of TPL2 tended to increase in dasatinib non-responder patients compared with that in responder patients. Our results indicate that activation of ERK1/2 by elevated MOS and TPL2 expression is involved in dasatinib resistance, and inhibition of these proteins overcomes dasatinib resistance. Therefore, MOS, TPL2 and ERK1/2 inhibitors may be therapeutically useful for treating BCR::ABL1-independent dasatinib-resistant CML.