Tumor Xenografts Research Articles

BRD9 promotes the malignant phenotype of thyroid cancer by activating the MAPK/ERK pathway

Thyroid cancer is one of the most common endocrine gland malignancies in China. During gene transcription, the bromodomain and extraterminal domain (BET) proteins perform epigenome interpretation tasks. Bromodomain-containing protein 9 (BRD9) is one of the BET family members. Increasing evidence has implicated that BRD9 plays significant roles in multiple malignancies. However, its role in thyroid cancer is still not fully understood. In this research, our results demonstrated that high expression of BRD9 can facilitate the malignant phenotype of thyroid cancer cell lines, while low expression of BRD9 can impede the malignant phenotype of thyroid cancer cell lines. Pharmacologically, I-BRD9 treatment inhibits the proliferation and promotes the rate of apoptosis in thyroid cancer cell lines. Moreover, our results also revealed that BRD9 promoted xenograft tumor growth. In addition, our study showed that the expression of mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) pathway-related proteins was decreased in BRD9 knockdown thyroid cancer cells, such as Raf, ERK, p-ERK, c-Fos, and c-Myc, which could be significantly reversed by overexpressing the BRD9 in different thyroid cancer cells. After the specific inhibitor of ERK (SCH772984) was applied to thyroid cancer cells (BCPAP cells) overexpressing the BRD9 gene, the results suggested that SCH772984 reverses the high expression of MAPK/ERK pathway-associated protein in BCPAP cells (over-expression BRD9 cells). In conclusion, this study demonstrated that BRD9 was highly expressed in serum and malignant tumor tissues of thyroid cancer patients and further promoted the development of the malignant phenotype of thyroid cancer by activating the MAPK/ERK signaling pathway.

Metformin Induces Apoptosis and Ferroptosis of Ovarian Cancer Cells Under Energy Stress Conditions

As ovarian cancer progresses, increased glucose use causes a glucose shortage in the tumor microenvironment. Therefore, it is crucial to find drugs that can effectively kill cancer cells in this energy stress setting. Here, we propose an effective therapeutic strategy that combines nutrient restriction with metformin to combat tumors. This study investigated the effects of metformin on ovarian cancer cells under energy stress conditions, mimicking the nutrient-deprived tumor microenvironment. We revealed that Metformin (10 mM) significantly reduced cell viability and proliferation under glucose deprivation conditions. Furthermore, it enhanced apoptosis and ferroptosis, as demonstrated by alterations in apoptotic protein expression and elevated levels of lipid reactive oxygen species (ROS), malondialdehyde (MDA), lipid peroxidation (LPO), and Fe2+. Transcriptional profiling revealed significant alterations in genes related to iron homeostasis and oxidative phosphorylation. Moreover, Metformin was found to induce mitochondrial dysfunction without affecting mitochondrial DNA or the expression of enzymes in the tricarboxylic acid (TCA) cycle, resulting in decreased ATP production and compromised activities of the respiratory chain complexes. The direct interaction between metformin and the NDUFB4 subunit in mitochondrial complex I was corroborated through the application of cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DARTS) assays. In vivo, the combination of metformin and fasting cycles significantly inhibited SKOV3 cell-derived xenograft tumors in immunodeficient mice. Altogether, we have demonstrated that Metformin potentiates apoptosis and ferroptosis in ovarian cancer cells under energy stress conditions by targeting the NDUFB4 subunit of mitochondrial complex I, thus laying the groundwork for clinical testing. This study, though limited to cellular and animal levels, provides valuable insights into the therapeutic potential of metformin in ovarian cancer treatment.

SLC25A1 promotes lymph node metastasis of esophageal squamous cell carcinoma by regulating lipid metabolism.

Solute carrier family 25 member 1 (SLC25A1) affects lipid metabolism and energy regulation in multiple types of tumor cell, affecting their proliferation and survival. To the best of our knowledge, however, the impact of SLC25A1 on the proliferation and survival of esophageal squamous cell carcinoma (ESCC) cells has yet to be explored. Here, SLC25A1 expression was detected in ESCC tissues and cell lines. SLC25A1 was silenced or blocked by lentivirus transfection or 2‑[(4‑chloro‑3‑nitrophenyl)sulfonylamino]benzoic acid in ESCC cells. To evaluate the impact of SLC25A1 on in vivo and in vitro proliferation, invasion and migration of ESCC cells, Cell Counting‑Kit, wound healing, colony formation, Transwell, EdU, flow cytometry, tumor xenograft in nude mice, lipid metabolism and energy metabolism detection assays were performed. Reverse transcription‑quantitative PCR and western blot analysis were performed to determine expression of downstream molecules and pathway proteins following the silencing and blockade of SLC25A1. SLC25A1 was significantly overexpressed in ESCC tissue and cell lines. The targeted silencing of SLC25A1 or inhibition of its protein led to a significant decrease in proliferative, invasive and migratory capabilities of ESCC cells, accompanied by increased apoptosis. Additionally, silencing of the SLC25A1 gene significantly inhibited xenograft tumor growth in vivo. The present results indicate that knockdown or blockade of SLC25A1 can significantly impede the malignant biological behavior of ESCC.

PPARα-mediated lipid metabolism reprogramming supports anti-EGFR therapy resistance in head and neck squamous cell carcinoma

Anti-epidermal growth factor receptor (EGFR) therapy (cetuximab) shows a limited clinical benefit for patients with locally advanced or recurrent/metastatic head and neck squamous cell carcinoma (HNSCC), due to the frequent occurrence of secondary resistance mechanisms. Here we report that cetuximab-resistant HNSCC cells display a peroxisome proliferator-activated receptor alpha (PPARα)-mediated lipid metabolism reprogramming, with increased fatty acid uptake and oxidation capacities, while glycolysis is not modified. This metabolic shift makes cetuximab-resistant HNSCC cells particularly sensitive to a pharmacological inhibition of either carnitine palmitoyltransferase 1A (CPT1A) or PPARα in 3D spheroids and tumor xenografts in mice. Importantly, the PPARα-related gene signature, in human clinical datasets, correlates with lower response to anti-EGFR therapy and poor survival in HNSCC patients, thereby validating its clinical relevance. This study points out lipid metabolism rewiring as a non-genetic resistance-causing mechanism in HNSCC that may be therapeutically targeted to overcome acquired resistance to anti-EGFR therapy.

Gamma-Tocotrienol Inhibits Proliferation and Growth of HSD17B4-Overexpressing HepG2 Liver Cancer Cells.

Hydroxysteroid 17-beta dehydrogenase 4 (HSD17B4) is involved in the progression of hepatocellular carcinoma (HCC). This study aimed to investigate the inhibitory effect of gamma-tocotrienol (γ-T3) on the proliferation and growth of HSD17B4-overexpressing HepG2 cells. HepG2 cells were transfected with empty or HSD17B4-overexpressing plasmids, followed by vitamin E (VE) or γ-T3 treatment. MTS assay, Western blotting, qRT-PCR, and flow cytometry were employed to assess cell proliferation, protein expression, mRNA levels, and apoptosis. HSD17B4 interaction with γ-T3 was assessed by quantifying γ-T3 in the collected precipitate of HSD17B4 using anti-flag magnetic beads. Tumor xenografts were established in NSG mice, and tumor growth was monitored. HSD17B4 overexpression significantly promoted HepG2 cell proliferation, which was effectively counteracted by VE or γ-T3 treatment in a dose-dependent manner. VE and γ-T3 did not exert their effects through direct regulation of HSD17B4 expression. Instead, γ-T3 was found to interact with HSD17B4, inhibiting its activity in catalyzing the conversion of estradiol (E2) into estrone. Moreover, γ-T3 treatment led to a reduction in cyclin D1 expression and suppressed key proliferation signaling pathways, such as ERK, MEK, AKT, and STAT3. Additionally, γ-T3 promoted apoptosis in HSD17B4-overexpressing HepG2 cells. In an in vivo model, γ-T3 effectively reduced the growth of HepG2 xenograft tumors. In conclusion, our study demonstrates that γ-T3 exhibits potent anti-proliferative and anti-tumor effects against HepG2 cells overexpressing HSD17B4. These findings highlight the therapeutic potential of γ-T3 in HCC treatment and suggest its role in targeting HSD17B4-associated pathways to inhibit tumor growth and enhance apoptosis.

Triptolide's impact on ACER1 signaling: Inducing autophagy for triple-negative breast cancer suppression.

Given the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2) in triple-negative breast cancer (TNBC) cells, the efficacy of targeted therapies is limited. In this study, we uncovered that triptolide (TP) effectively suppresses the migration and invasiveness of MDA-MB-231 cells by activating autophagic pathways. Western blotting analysis revealed that TP significantly reduced the expression levels of p62 protein, while simultaneously markedly increasing the expression levels of LC3B-II, BNIP3, BNIP3L, ATG5, and ULK1 proteins, strongly suggesting an enhancement of autophagic activity in the cells. Based on PCR array screening, we identified the ACER1 gene as exhibiting notable expression alterations post-TP treatment. Overexpression of ACER1 gene enhanced the TP-induced apoptosis in MDA-MB-231 cells and augmented the regulation of autophagy-related proteins p62 and LC3B-II, leading to an increase in autophagosome numbers and a marked reduction in cellular migration and invasiveness. Conversely, ACER1 gene knockdown reversed these effects. In vivo experiments demonstrated that TP effectively inhibits the growth of MDA-MB-231 xenograft tumors, concurrently upregulating ACER1 and LC3B-II expression in tumor tissues, while p62 protein levels were notably decreased. Hematoxylin and eosin (H&E) staining results indicated no evident toxicity in liver and kidney tissues of BALB/c mice at a TP dose of 0.4 mg/kg. This study, for the first time, elucidates a novel mechanism by which TP inhibits TNBC through an autophagic process mediated by ACER1.

Pleiotropic Anti-Cancer Activities of Novel Non-Covalent Thioredoxin Reductase Inhibitors Against Triple Negative Breast Cancer

Mounting evidence shows that tumor growth and progression rely on thioredoxin reductase 1 (TXNRD1)-mediated detoxification of oxidative stress that results from deregulated metabolism and mitogenic signaling in tumors. TXNRD1 levels are significant higher in triple negative breast cancer (TNBC) compared to normal tissue, making TXNRD1 a compelling TNBC therapeutic target. Despite the many attempts to generate TXNRD1 inhibitors, all known and reported compounds inhibiting TXNRD1 are problematic; they interact with TXNRD1 irreversibly and non-specifically resulting in numerous adverse side effects. Recently, a series of breakthrough studies identified a novel regulatory site, the ‘doorstop pocket’, in Schistosoma mansoni thioredoxin glutathione reductase, a TXNRD-like enzyme and an established drug target for the human parasitic infection, schistosomiasis. This discovery underpins the development of new first-in-class non-covalent inhibitors for this family of enzymes.Our data show that novel non-covalent TXNRD inhibitors (TXNRD(i)s) are potent dose-dependent inhibitors of viability in cellular models of TNBC. TXNRD(i)s attenuate several aggressive cancer phenotypes such as, clonogenic survival, mammosphere forming efficiency, invasion, and TXNRD-related gene expression in TNBC cells. TXNRD(i)s engage and inhibit TXNRD1 in live TNBC cells and xenograft tumors, thus supporting the mechanism of action at a cellular level. More importantly, TXNRD(i)s attenuated tumor growth in a preclinical MDA-MB-231 TNBC xenograft mouse model. Although additional optimization for TXNRD(i)s’ potency is warranted, these results may open a new avenue for the development of novel small molecule therapeutics for TNBC.

SUMO modified ETV1 promotes M2-polarized tumor-associated macrophage infiltration and cancer progression by facilitating CCL2 transcription in esophageal squamous cell carcinoma cells.

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors with a high metastasis rate and a poor prognosis. ETS variant transcription factor 1 (ETV1) plays an important role in multiple malignancies. However, its function in ESCC progression and tumor microenvironment (TME) remains to be explored. In this study, we characterized the role of ETV1 in ESCC process and TME. Gene expression and immune infiltration in ESCC samples from the Cancer Genome Atlas (TCGA) were analyzed. The expression of ETV1 in clinical samples was detected by real-time PCR, western blot and immunohistochemistry staining. Cell growth was detected by CCK-8 and colony formation assays. Macrophage phenotypes were determined using flow cytometry. Immunofluorescence double staining was used to detect the tumor-associated macrophage (TAM) infiltration. The tumor volume was recorded and weighed. Transcriptional activity was measured using dual-luciferase assay, chromatin immunoprecipitation (ChIP) assay and DNA pull-down assay. In this study, through analysis of ESCC samples from TCGA database and the clinic, we noticed that ETV1 was highly expressed in ESCC tumor tissues and was associated with TAM infiltration. Overexpression of ETV1 promoted ESCC cell proliferation in vitro and xenograft tumor growth in nude mice, while ETV1 knockdown elicited the opposite effects. Furthermore, ETV1 upregulation in tumor tissues was found to drive M2 macrophage infiltration both in vitro (transwell assays) and in vivo (xenograft tumor models). C-C motif chemokine ligand 2 (CCL2), a key factor inducing M2 macrophage polarization, was also found to be elevated in ESCC tumor tissues. Mechanism study demonstrated that ETV1 facilitated M2 macrophage infiltration via the transcriptional modulation of CCL2. In addition, the cause of the changes in ETV1 activity and expression was investigated. The E2 small ubiquitin-like modifier (SUMO) binding enzyme UBC9 increased ETV1 activity and expression, indicating the presence of SUMO modification in ETV1. Our data deciphered the mechanism of ETV1-mediated M2 macrophage infiltration in the TME of ESCC, which has important implications for the development of novel prognostic and therapeutic targets to optimize current therapies against ESCC.

Expression of Lymphoid Enhancer-Binding Factor 1 in Cancer-Associated Fibroblasts Mediates Tumor Growth and Transdifferentiation Toward Squamous Cell Carcinoma in Human Breast Cancer.

Cancer-associated fibroblasts (CAFs) play a significant role in human breast cancer as a major stromal component. While their role in promoting cancer proliferation and malignancy through interaction with cancer cells in the tumor microenvironment is known, the exact mechanisms behind this interaction are not fully understood. Our study reveals that lymphoid enhancer-binding factor 1 (LEF1), a central transcription factor for Wnt/β-catenin signaling, is expressed in experimentally generated tumor-promoting CAFs (exp-CAFs) as well as in CAFs from breast cancer patients, particularly those with a poor prognosis. Notably, LEF1-expressing CAFs are prevalent in the stroma of squamous cell carcinoma (SCC), an aggressive metaplastic breast cancer subtype with a limited understanding of its development. To investigate the functional importance of LEF1 expression in CAFs, we depleted LEF1 in the exp-CAFs and subcutaneously implanted them along with breast ductal carcinoma MCF10DCIS.com cells into immunodeficient mice. Depleting LEF1 resulted in reduced xenograft tumor growth, accompanied by decreased cancer-cell proliferation and angiogenesis in the tumors. Additionally, we observed a significant reduction in the expression of SCC markers p40 (ΔNp63) and cytokeratin 5/6 in the xenograft tumors when LEF1 was depleted in the exp-CAFs. Furthermore, we identified 13 genes, none of which are established downstream genes of the Wnt/β-catenin pathway, that exhibit expression patterns similar to LFE1 in our cultured fibroblasts. In summary, our findings suggest that LEF1 expression contributes to the tumor-promoting abilities of breast CAFs and that LEF1-expressing CAFs may drive transdifferentiation toward SCC, possibly through a pathway independent of the canonical Wnt/β-catenin signaling.

AGX101: A TM4SF1-directed tubulin inhibitor conjugate in ongoing first-in-human trial including GI cancers.

829 Background: TM4SF1 (Transmembrane-4 L-Six-Family-Member-1) is an endothelial marker with critical roles in angiogenesis, as well as a tumor cell antigen that contributes significantly to invasion and metastasis. TM4SF1 is upregulated 20-fold in angiogenic tumor vascular endothelium compared to normal vasculature endothelium and exhibits a unique nuclear internalization pathway. AGX101 is a novel tubulin inhibitor conjugate specifically directed against TM4SF1, delivering a potent maytansinoid payload directly to the nucleus of cells within the tumor microenvironment. Delivery to both the vascular and tumor cell compartments of the tumor results in three mechanisms of action (MoAs): (1) activation of tumor immune surveillance, (2) tumor blood supply deprivation, and (3) direct tumor cell killing. Methods: TM4SF1 expression was assessed using immunohistochemistry. Safety and pharmacokinetics of AGX101 were evaluated in non-human primates (NHP), with escalating doses to determine the highest non-severely toxic dose (HNSTD). Efficacy studies were also conducted in mouse models, enabling assessment of the minimum effective dose (MED) needed to engage each of the three MoAs. The combination of HNSTD and MED enables calculation of a therapeutic index (TI). The potential for synergy with immune checkpoint inhibitors (ICIs) was also investigated. A first-in-human study of AGX101 in patients with advanced solid tumors with the primary objective of safety and dose-limiting toxicities (DLTs) has initiated. Results: Notable cancers with high TM4SF1 scoring intensity include pancreatic adenocarcinoma, hepatocellular carcinoma, cholangiocarcinoma, and gastric cancer. In esophageal cancer, 20% of patients have a TM4SF1 copy number amplification, and these have worse prognosis. In NHP, AGX101 exhibited a favorable safety profile. In preclinical efficacy studies, monotherapy demonstrated robust efficacy through each of the three MoAs in syngeneic models in mice including CT26 colon carcinoma, and human tumor xenograft models including MIA PaCa-2 pancreatic cancer. Measured by exposure, TI was large. In syngeneic mouse models including CT26, the effects of ICIs were potentiated, suggesting a potential synergistic approach in cancer therapy. The first two dose levels of AGX101 monotherapy in humans has cleared without DLTs. Three patients with pancreatic adenocarcinoma have been treated thus far. Conclusions: AGX101, targeting the TM4SF1 antigen, represents a promising new approach in cancer therapy. The preclinical data suggest that AGX101 could provide a significant therapeutic benefit by novel and differentiated mechanisms of action, namely selectively targeting the tumor vasculature and potentiating immune-based therapies. Further clinical development of AGX101 is ongoing and initial outcome data will become available by the conference. Clinical trial information: NCT06440005 .

Acquired vulnerability against EGF receptor inhibition in gastric cancer promoted by class I histone deacetylase inhibitor entinostat.

Histone deacetylase inhibitors (HDACi) have shown promising preclinical activity in gastric cancer cells; unfortunately, however, these could not be confirmed in clinical trials. This highlights the need for the identification of underlying reasons, which may also provide the basis for possible combination therapies. Here, we delineated the effects of HDACi on components of EGFR signalling in gastric cancer cells. We investigated entinostat effects on EGFR and amphiregulin (AREG) expression in various cell line- and primary patient tumor-based in vitro, ex vivo and in vivo models, on the mRNA and protein level. Based on these results, a combined entinostat plus EGFR inhibitor erlotinib treatment in vitro and in vivo was studied. Proteomics analyses in gastric cancer cells treated with entinostat revealed a marked upregulation of EGFR in the majority of cell lines and an even more robust induction of the EGFR ligand AREG. This was confirmed in a panel of different cell lines in vitro, in tumor tissue-slice cultures ex vivo and in cell line- or patient-derived tumor xenografts in mice. Since previous studies in other tumor entities showed a downregulation of EGFR by HDACi, our findings thus indicate essential differences in the adaptive response of gastric carcinoma cells. Moreover, our results provided the basis for combined entinostat + EGFR inhibitor (erlotinib) treatment, and indeed we demonstrate synergistic effects in combination therapy studies. Our findings establish the profound upregulation of the EGFR/AREG axis by entinostat as starting point for a rational combination therapy in gastric carcinoma.

EMC2 suppresses ferroptosis via regulating TFRC in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an epithelial malignancy with poorly understood underlying molecular mechanisms. Ferroptosis, a form of programmed cell death, is not fully elucidated in NPC. We conducted quantitative proteomics to detect dysregulated proteins in NPC tissues. The levels of endoplasmic reticulum membrane protein complex 2 (EMC2) in NPC tissue microarrays were evaluated by immunohistochemistry, and the prognostic value of EMC2 was analyzed in NPC patients. The role of EMC2 in ferroptosis and carcinogenesis was determined through in vitro and in vivo experiments. Quantitative proteomics, protease inhibition, ubiquitin detection, and rescue experiments were performed to explore the mechanism of EMC2-regulated ferroptosis. Significantly upregulated EMC2 was detected in NPC, and it was closely related to the characteristics of tumor progression. Elevated EMC2 was obviously correlated with poor survival in patients with NPC. EMC2 knockdown promoted ferroptosis, inhibiting cell viability, migration, and invasion, and enhancing the efficacy of cisplatin in NPC cells. Conversely, EMC2 overexpression contributed to ferroptosis repression, malignant progression, and reduced the efficacy of cisplatin. In addition, EMC2 knockdown suppressed xenograft tumor growth and enhanced ferroptosis in nude mice. Mechanistically, we identified transferrin receptor (TFRC) as a critical downstream protein. EMC2 interacted with TFRC and promoted its ubiquitin-proteasomal degradation. EMC2 regulated ferroptosis by mediating the level of TFRC. EMC2 suppresses ferroptosis and promotes tumor progression, and the EMC2-TFRC axis is a novel ferroptosis regulatory pathway. EMC2 is a potentially biomarker and therapeutic target for NPC.

Design, synthesis, and biological evaluation of N1-(2-(adamantan-1-yl)-1H-indol-5-yl)-N2-(substituent)-1,2-dicarboxamides as anticancer agents targeting Nur77-mediated endoplasmic reticulum stress.

Targeting endoplasmic reticulum (ER) stress-induced apoptosis has attracted considerable research interest in anti-cancer drug development. Nur77 is a potential therapeutic target in many cancers and several Nur77 modulators have recently been identified as effective anticancer agents by activating ER stress. As an ongoing work, this study reports a new series of novel N1-(2-(adamantan-1-yl)-1H-indol-5-yl)-N2-(substituent)-1,2-dicarboxamides as potent Nur77 modulators that cause ER stress-induced apoptosis. Among this new series, most compounds show improved cytotoxicity against liver cancer (HepG2 and Huh7) and breast cancer (MCF-7 and MDA-MB-231) cell lines. The representative analog 15h dramatically induces Nur77 expression and cell apoptosis, showing excellent growth inhibition of HepG2 and MCF-7 cells (IC50<5.0μM). Mechanistically, 15h binds (KD=0.477μM) and activates Nur77-mediated ER stress through the PERK-ATF4 and IRE1 signaling pathways, thereby inducing cell apoptosis. In vivo, 15h treatment strongly suppresses HepG2 xenograft tumor growth (tumor shrink by 54.06%). In summary, we synthesize a series of novel indole derivatives, among which 15h has significantly improved pharmacological activity against various cancer cells. We further identify 15h as a novel ligand of Nur77, which may serve a therapeutic lead for developing new cancer therapy.

Bcl‑xL‑specific BH3 mimetic A‑1331852 suppresses proliferation of fluorouracil‑resistant colorectal cancer cells by inducing apoptosis.

BH3 mimetics are small‑molecule inhibitors of the antiapoptotic Bcl‑2 family and have therapeutic efficacy against hematological malignancies. BH3 mimetic A‑1331852 suppresses colorectal cancer cell proliferation. Progressive resistance to the widely used anticancer agent fluorouracil (5‑FU) is a key reason for colorectal cancer recurrence; therefore, the present study tested if A‑1331852 can suppress the proliferation of 5‑FU‑resistant colorectal cancer cells. A 5‑FU‑resistant colorectal cancer cell line was derived from HCT116 cells and compared with the parental line. Expression levels of the antiapoptotic Bcl‑2 proteins Bcl‑xL and myeloid cell leukemia 1 (Mcl‑1) were determined via western blotting, proliferation in the presence of 5‑FU and following small interfering (si)RNA‑mediated Bcl‑xL or Mcl‑1 knockdown was assessed by WST‑1 assay and sensitivity to A‑1331852‑induced apoptosis was assessed via western blotting and DNA fragmentation assay. In addition, a xenograft mouse model of 5‑FU‑resistant colorectal cancer was established via subcutaneous inoculation of 5‑FU‑resistant HCT116 cells to examine the in vivo antitumor efficacy of A‑1331852. Compared with the parental line, 5‑FU‑resistant cells overexpressed Bcl‑xL. Knockdown of Bcl‑xL by siRNA and treatment with A‑1331852 suppressed proliferation and induced the apoptosis of both 5‑FU‑resistant and parental HCT116 cells, but the potency of both effects was stronger in 5‑FU‑resistant than parental HCT116 cells. Furthermore, A‑1331852 suppressed the growth of xenograft tumors derived from 5‑FU‑resistant cells by inducing apoptosis. Overall, the present findings suggested that Bcl‑xL upregulation contributes to 5‑FU resistance of colorectal cancer and targeted inhibition by A‑1331852 may be an effective treatment strategy.

USP34 regulates PIN1-cGAS-STING axis-dependent ferroptosis in cervical cancer via SUMOylation.

Cervical cancer is a prevalent form of cancer in women, and the inhibition of ferroptosis has been shown to promote the progression of cervical cancer tumours. This study aimed to investigate the role of PIN1 in regulating ferroptosis in cervical cancer, focusing on its ability to modulate the cGAS-STING pathway and the potential involvement of USP34 as an upstream regulator of PIN1. PIN1-overexpressing and PIN1-knockdown cell lines were constructed. In addition to activating p-STING via PIN1 knockdown and inhibiting p-STING via PIN1 overexpression, cell activity was evaluated via CCK8, EdU, transwell and flow cytometry assays. The expression of USP34, PIN1, cGAS, p-STING, and STING was analysed through qRT-PCR and immunofluorescence. Western blot analysis was used to detect the regulatory effects of USP34, PIN1, cGAS, p-STING, and STING, as well as SUMOylation. Ferroptosis was detected by ROS immunofluorescence, the mitochondrial membrane potential, and mitochondrial electron microscopy. Furthermore, PIN1-knockdown cells were used to construct xenograft tumours in BALB/c male nude mice, and the relevant verification experiments were performed in vivo. PIN1 can increase the proliferation and invasion of cervical cancer cells by significantly inhibiting ferroptosis. The mechanism by which PIN1 promotes cancer is inhibition of the cGAS-STING pathway. Additionally, we found that USP34 could increase the expression of PIN1 via SUMOylation in cervical cancer cells. This study confirmed that USP34 could upregulate PIN1 expression and SUMOylation, thereby inhibiting ferroptosis by suppressing the cGAS-STING pathway and in turn promoting the progression of cervical cancer.

Construction and characterization of a novel secreted MsC-CAR-T cell in solid tumors

The CD47-SIRPα signaling has been acknowledged as a significant immune checkpoint and CD47 blocking has been proved as a potential therapeutic strategy for the treatment of solid tumor. However, the potential application of CAR-T cells secreted antibody fragment simultaneously in solid tumor is rarely explored. In this study, we searched bioinformatic databases and investigated the characteristics of CD47 in solid tumors. Then we consulted bioinformatic databases to design, optimize and construct a novel MsC-CAR which could target MAGE-A1 and self-secrete CD47-scFv. The engineering T cells containing MsC-CAR were transfected, verified and characterized. The tumor-inhibitory role of MsC-CART cells was further determined in vitro and in vivo. The results showed that MsC-CARs were successfully constructed and MsC1-CARs demonstrated the preferable features of recognizing MAGE-A1 and secreting CD47-scFv. Engineering T cells transfecting with MsC1-CAR (MsC1-CART cells) exerted the prominent tumor-inhibitory effectiveness, both in different cancer cell lines and LUAD xenograft tumors. The present data highlighted that MsC1-CART cells elaborately combined the adoptive cellular immunotherapy and immune checkpoint inhibitor therapy, may represent a new direction for the treatment of MAGE-A1 positive solid tumors.

Effect of tRF-28-ZJ47D112Z4DZ on the pathogenesis of gastric cancer through targeting cyclin D1/CDK4 and its early diagnostic value.

475 Background: Gastric cancer exhibits high incidence and mortality rates worldwide. Current research on gastric cancer aims to discover stable and effective early diagnostic markers, as well as uncover the disease's pathogenesis. tRNA-derived fragment (tRF) is a newly discovered regulatory non-coding RNA, which plays an important role in tumor diagnosis and treatment. Methods: This study, through transcriptome sequencing and MINTBase v2.0 database, screened out a new molecule tRF-28-ZJ47D112Z4DZ (tRF-28) related to gastric cancer. An absolute quantitative method was established to quantify the level of tRF-28 in plasma. ROC curve, survival curve, Cox regression model were constructed, and clinicopathological factors were collected to analyze the diagnostic value of tRF-28. "Overexpression" and "knockdown" tRF-28 gastric cancer cell models and xenograft tumor models were established to study the effects of tRF-28 on cell proliferation. Using bioinformatics, qRT-PCR, Western blot, dual luciferase reporter gene, fluorescence in situ hybridization, RNA binding protein immunoprecipitation assay, rescue experiment and immunohistochemistry to study the regulatory role of tRF-28 by binding to the 3'UTR of CCND1. Results: This study clarified the tRF-28 levels in the plasma of healthy individuals, and gastric benign and malignant lesions, providing a new candidate biomarker for the early diagnosis of gastric cancer. Through upregulating and downregulating the level of tRF-28 in gastric cancer cells, it was revealed that tRF-28 inhibits the proliferation of gastric cancer cells in vivo and in vitro by regulating key proteins such as Cyclin D1, CDK4, Rb, and p-Rb. In studying specific molecular mechanisms, tRF-28 and CCND1 were co-located in the cytoplasm. tRF-28 combines with Ago2 protein to form a complex and plays a role in silencing the target gene CCND1 in the cytoplasm. The rescue experiments revealed that silencing the target gene CCND1 can reverse the carcinogenesis effect of tRF-28 inhibitors, clarifying the biological functions of tRF-28 by regulating CCND1. Conclusions: Based on a series of research findings, we elucidated that tRF-28 form a complex with Ago2 protein, binding to the 3' UTR of CCND1 to downregulate Cyclin D1, CDK4, and other critical proteins, thereby inhibiting the proliferation of gastric cancer cells. Our study aims to offer new insights into identifying potential early diagnostic markers and therapeutic targets for gastric cancer.

Increased phosphorylation of AMPKα1 S485 in colorectal cancer and identification of PKCα as a responsible kinase.

The present study attempts to examine the biological effect of phosphorylation of AMPKα1 S485 and identify the responsible kinase in colon cancer cells. Thus, our results showed that S485 phosphorylation was increased in colorectal cancer specimens as compared with adjacent normal tissues, which was inversely correlated to phosphorylation of T172. Our study further revealed that phosphorylation of S485 on AMPKα1 plays a promoting role in cell proliferation, colony formation, migration and growth of Xenograft tumor. Furthermore, we identified PKCα as a kinase specific for phosphorylation of S485. First, under the basal condition, S485 phosphorylation was blunted by Gö6983, a pan PKC inhibitor, but not by Akt inhibitor, MK2206, although the latter countered off the insulin-stimulated phosphorylation. Second, the phosphorylation was enhanced by PMA and attenuated by sgRNA for PKCα, but not by PKCγ and PKCδ, neither by siRNA for Akt1. Third, the phosphorylation was suppressed by shRNA for PLCγ1. Fourth, the phosphorylation was enhanced by ectopically expressing a constitutively active mutant of PKCα, but not PKCγ. Finally, the increase of S485 phosphorylation by high glucose or palmitic acid was almost completely abolished by Gö6983. Altogether, our data reinforced the tumor suppressive function of AMPK and demonstrated that PKCα is a major kinase responsible for phosphorylation of S485, which contributes to one of the mechanisms underlying the regulation of AMPK in cancer cells in response to nutritional conditions.

Estrogen Promotes the Proliferation and Migration of Endometrial Cancer Through the GPER-Mediated NOTCH Pathway.

This study aims to investigate the expression of GPER in EC, assess the impact of estrogen on the proliferation and migration of EC via GPER, and examine the potential role of GPER in mediating the NOTCH pathway to influence EC proliferation and migration. The expression of GPER and its correlation with clinicopathological features were investigated using clinical data. Cell proliferation was assessed through MTT and EdU assays, while cell migration ability was evaluated using wound healing and transwell assays. Western blot analysis was conducted to detect proteins associated with the GPER and NOTCH signaling pathways. Additionally, xenograft tumor models were established to investigate the potential role of estrogen in mediating the NOTCH pathway via GPER. The results demonstrated a significant upregulation of GPER expression in EC, which was associated with clinical stage and metastasis. In vitro experiments provided evidence that estrogen promotes EC cell proliferation and metastasis by enhancing the expression levels of GPER, Notch1, and Hes-1 proteins. Conversely, knocking down or suppressing GPER effectively reverses these effects. Furthermore, treatment with JAG-1, an agonist for the NOTCH pathway, counteracts si-GPER's inhibitory impact on both proliferation and migration abilities of EC cells while increasing Notch1 and Hes-1 protein expression levels; however, it does not alter GPER expression. In vivo experiments have substantiated that estrogen facilitates EC proliferation via the GPER-mediated NOTCH pathway.

High expression of ARPC1B promotes the proliferation and apoptosis of clear cell renal cell carcinoma cells, leading to a poor prognosis.

ARPC1B has been identified as a key regulator of malignant biological behavior in various tumors. However, its specific role in clear cell renal cell carcinoma (ccRCC) remains poorly understood. This study aims to evaluate the influence of ARPC1B on the prognosis and disease progression in ccRCC patients. Multi-omics data and clinical information from public databases were analyzed to determine the associations between ARPC1B and prognosis, clinical features, immune microenvironment, and drug sensitivity in ccRCC. Co-expression and gene set enrichment analyses were conducted to elucidate the potential role of ARPC1B in ccRCC pathogenesis. Functional assays, including RT-qPCR, CCK8 assays, colony formation assays, immunofluorescence, immunohistochemistry, and xenograft tumor formation in nude mice, were performed to assess ARPC1B's impact on cell proliferation and apoptosis. Flow cytometry and Western blotting were further employed to investigate the underlying molecular mechanisms of ARPC1B in ccRCC. ARPC1B expression was significantly elevated in ccRCC and associated with an unfavorable prognosis. Both independent and meta-analyses confirmed that ARPC1B is an independent prognostic risk factor in ccRCC. Furthermore, ARPC1B expression significantly correlated with the immune microenvironment and drug sensitivity. In vitro, experiments demonstrated that ARPC1B knockdown suppressed ccRCC cell proliferation and induced apoptosis through the BAX-Bcl-2/c-caspase3/c-PARP axis, which was further validated by in vivo studies. ARPC1B overexpression is associated with poor prognosis, altered immune status, and drug sensitivity in ccRCC. Furthermore, ARPC1B promotes the malignant behavior of ccRCC cells and holds potential as a prognostic biomarker and therapeutic target for ccRCC.