Inhibition of KIF20A enhances the immunotherapeutic effect of hepatocellular carcinoma by enhancing c-Myc ubiquitination.

Immune therapy has significantly improved the prognosis of hepatocellular carcinoma (HCC) patients, yet its efficacy remains limited, underscoring the urgency to identify new therapeutic targets and biomarkers. Here, we investigated the pathological and physiological roles of KIF20A and assess its potential in enhancing HCC treatment efficacy when combined with PD-1 inhibitors. We initially assess KIF20A's oncogenic function using liver-specific KIF20A knockout (Kif20a CKO) mouse models and orthotopic xenografts. Subsequently, we establish a regulatory axis involving KIF20A, FBXW7, and c-Myc, validated through construction of c-Myc splicing mutants. Large-scale clinical immunohistochemistry (IHC) analyses confirm the pathological relevance of the KIF20A-FBXW7-c-Myc axis in HCC. We demonstrate that KIF20A overexpression correlates with poor prognosis in HCC by competitively inhibiting FBXW7-mediated degradation of c-Myc, thereby promoting glycolysis and enhancing tumor proliferation. Conversely, KIF20A downregulation suppresses these effects, impairing tumor growth through c-Myc downregulation. Notably, KIF20A inhibition attenuates c-Myc-induced MMR expression, associated with improved prognosis in HCC patients receiving PD-1 inhibitor therapy. Furthermore, in Kif20a CKO HCC mouse models, we observe synergistic effects between Kif20a knockout and anti-PD-1 antibodies, significantly enhancing immunotherapeutic efficacy against HCC. Our findings suggest that targeting the KIF20A-c-Myc axis could identify HCC patients likely to benefit from anti-PD-1 therapy. In conclusion, we propose that combining KIF20A inhibitors with anti-PD-1 treatment represents a promising therapeutic strategy for HCC, offering new avenues for clinical development and patient stratification.

A positive feedback loop between PFKP and c-Myc drives head and neck squamous cell carcinoma progression.

BACKGROUND: The aberrant expression of phosphofructokinase-platelet (PFKP) plays a crucial role in the development of various human cancers by modifying diverse biological functions. However, the precise molecular mechanisms underlying the role of PFKP in head and neck squamous cell carcinoma (HNSCC) are not fully elucidated. METHODS: We assessed the expression levels of PFKP and c-Myc in tumor and adjacent normal tissues from 120 HNSCC patients. A series of in vitro and in vivo experiments were performed to explore the impact of the feedback loop between PFKP and c-Myc on HNSCC progression. Additionally, we explored the therapeutic effects of targeting PFKP and c-Myc in HNSCC using Patient-Derived Organoids (PDO), Cell Line-Derived Xenografts, and Patients-Derived Xenografts. RESULTS: Our findings indicated that PFKP is frequently upregulated in HNSCC tissues and cell lines, correlating with poor prognosis. Our in vitro and in vivo experiments demonstrate that elevated PFKP facilitates cell proliferation, angiogenesis, and metastasis in HNSCC. Mechanistically, PFKP increases the ERK-mediated stability of c-Myc, thereby driving progression of HNSCC. Moreover, c-Myc stimulates PFKP expression at the transcriptional level, thus forming a positive feedback loop between PFKP and c-Myc. Additionally, our multiple models demonstrate that co-targeting PFKP and c-Myc triggers synergistic anti-tumor effects in HNSCC. CONCLUSION: Our study demonstrates the critical role of the PFKP/c-Myc positive feedback loop in driving HNSCC progression and suggests that simultaneously targeting PFKP and c-Myc may be a novel and effective therapeutic strategy for HNSCC.

DSG2 and c-MYC Interact to Regulate the Expression of ADAM17 and Promote the Development of Cervical Cancer.

Purpose: To explore the effect of DSG2 on the growth of cervical cancer cells and its possible regulatory mechanism. Methods: The expression levels and survival prognosis of DSG2 and ADAM17 in cervical squamous cell carcinoma tissues and adjacent normal tissues were analyzed by bioinformatics. CCK-8 assay, colony formation assay and Transwell assay were used to detect the effects of DSG2 on the proliferative activity, colony formation ability and migration ability of SiHa and Hela cells. The effect of DSG 2 on the level of ADAM17 transcription and translation was detected by qPCR and Western blot experiments. The interaction between DSG2 and c-MYC was detected by immunocoprecipitation. c-MYC inhibitors were used in HeLa cells overexpressing DSG2 to analyze the effects of DSG2 and c-MYC on proliferation, colony formation and migration of Hela cells, as well as the regulation of ADAM17 expression. Results: DSG2 was highly expressed in cervical squamous cell carcinoma compared with normal tissues (P<0.05), and high DSG2 expression suggested poor overall survival (P<0.05). After DSG2 knockdown, the proliferative activity, colony formation and migration ability of SiHa and Hela cells were significantly decreased (P<0.05). Compared with adjacent normal tissues, ADAM17 was highly expressed in cervical squamous cell carcinoma (P<0.05), and high ADAM17 expression suggested poor overall survival in cervical cancer patients (P<0.05). The results of immunocoprecipitation showed the interaction between DSG2 and c-MYC. Compared with DSG2 overexpression group, DSG2 overexpression combined with c-MYC inhibition group significantly decreased cell proliferation, migration and ADAM17 expression (P < 0.05). Conclusion: DSG2 is highly expressed in cervical cancer, and inhibition of DSG2 expression can reduce the proliferation and migration ability of cervical cancer cells, which may be related to the regulation of ADAM17 expression through c-MYC interaction.

Polyamine and EIF5A hypusination downstream of c-Myc confers targeted therapy resistance in BRAF mutant melanoma.

BACKGROUND: BRAF inhibitors are widely employed in the treatment of melanoma with the BRAF V600E mutation. However, the development of resistance compromises their therapeutic efficacy. Diverse genomic and transcriptomic alterations are found in BRAF inhibitor resistant melanoma, posing a pressing need for convergent, druggable target that reverse therapy resistant tumor with different resistance mechanisms. METHODS: CRISPR-Cas9 screens were performed to identify novel target gene whose inhibition selectively targets A375VR, a BRAF V600E mutant cell line with acquired resistance to vemurafenib. Various in vitro and in vivo assays, including cell competition assay, water soluble tetrazolium (WST) assay, live-dead assay and xenograft assay were performed to confirm synergistic cell death. Liquid Chromatography-Mass Spectrometry analyses quantified polyamine biosynthesis and changes in proteome in vemurafenib resistant melanoma. EIF5A hypusination dependent protein translation and subsequent changes in mitochondrial biogenesis and activity were assayed by O-propargyl-puromycin labeling assay, mitotracker, mitoSOX labeling and seahorse assay. Bioinformatics analyses were used to identify the association of polyamine biosynthesis with BRAF inhibitor resistance and poor prognosis in melanoma patient cohorts. RESULTS: We elucidate the role of polyamine biosynthesis and its regulatory mechanisms in promoting BRAF inhibitor resistance. Leveraging CRISPR-Cas9 screens, we identify AMD1 (S-adenosylmethionine decarboxylase 1), a critical enzyme for polyamine biosynthesis, as a druggable target whose inhibition reduces vemurafenib resistance. Metabolomic and proteomic analyses reveal that polyamine biosynthesis is upregulated in vemurafenib-resistant cancer, resulting in enhanced EIF5A hypusination, translation of mitochondrial proteins and oxidative phosphorylation. We also identify that sustained c-Myc levels in vemurafenib-resistant cancer are responsible for elevated polyamine biosynthesis. Inhibition of polyamine biosynthesis or c-Myc reversed vemurafenib resistance both in vitro cell line models and in vivo in a xenograft model. Polyamine biosynthesis signature is associated with poor prognosis and shorter progression free survival after BRAF/MAPK inhibitor treatment in melanoma cohorts, highlighting the clinical relevance of our findings. CONCLUSIONS: Our findings delineate the molecular mechanisms involving polyamine-EIF5A hypusination-mitochondrial respiration pathway conferring BRAF inhibitor resistance in melanoma. These targets will serve as effective therapeutic targets that can maximize the therapeutic efficacy of existing BRAF inhibitors.

C-MYC-activated lncRNA SNHG20 accelerates the proliferation of diffuse large B cell lymphoma via USP14-mediated deubiquitination of ß-catenin.

BACKGROUND: Long noncoding RNAs (lncRNAs) are implicated in the initiation and progression of diffuse large B-cell lymphoma (DLBCL). Small nucleolar RNA host gene 20 (SNHG20) has been recognized as a critical lncRNA in multiple human cancers. However, the role of SNHG20 and its underlying mechanism in DLBCL are still unclear. METHODS: The expression levels of SNHG20, c-MYC, ß-catenin, and ubiquitin-specific peptidase 14 (USP14) were measured by reverse transcription-quantitative polymerase chain reaction (RT‒qPCR) and immunoblotting. Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU) incorporation, and flow cytometry assays were used to assess the proliferation and apoptosis of DLBCL cells. The transcriptional regulation of SNHG20 by c-MYC was confirmed by a luciferase reporter assay and RNA immunoprecipitation. The interaction between USP14 and ß-catenin was demonstrated using coimmunoprecipitation. A subcutaneous xenograft model was constructed to determine the role of SNHG20 in vivo. RESULTS: In the present study, we found that SNHG20 expression was upregulated in DLBCL cell lines and tissues compared to their normal counterparts. SNHG20 knockdown prominently reduced the proliferation and induced the apoptosis of U2932 and OCI-LY3 cells. However, SNHG20 overexpression increased the proliferation and apoptosis resistance of DLBCL cells. Mechanistically, the expression of SNHG20 was positively regulated by c-MYC in DLBCL cells. C-MYC directly bound to the promoter of SNHG20 to activate its transcription. SNHG20 was expressed mainly in the cytosol in DLBCL cells. SNHG20 silencing did not impact USP14 expression but markedly decreased the level of ß-catenin, the substrate of USP14, in DLBCL cells. USP14 overexpression increased the ß-catenin level, and this increase was attenuated by SNHG20 knockdown. Treatment with the proteasome inhibitor MG132 abolished SNHG20 knockdown-induced ß-catenin downregulation. Moreover, SNHG20 silencing reduced the half-life but increased the ubiquitination of ß-catenin in DLBCL cells. SNHG20 knockdown weakened the interaction between both endogenous and exogenous USP14 and ß-catenin. In turn, SNHG20 overexpression increased the c-MYC level, and this increase was attenuated by ß-catenin knockdown. Importantly, ß-catenin knockdown attenuated the SNHG20-mediated increase in DLBCL cell proliferation in vitro and tumour growth in vivo. CONCLUSIONS: Taken together, our results suggested that c-MYC-activated SNHG20 accelerated the proliferation and increased the apoptosis resistance of DLBCL cells via USP14-mediated deubiquitination of ß-catenin. The c-MYC/SNHG20 positive feedback loop may be a new target for anti-DLBCL treatment.

Anti-Leukemic Effects of Small Molecule Inhibitor of c-Myc (10058-F4) on Chronic Myeloid Leukemia Cells.

BACKGROUND: As one of the main molecules in BCR-ABL signaling, c-Myc acts as a pivotal key in disease progression and disruption of long-term remission in patients with CML. OBJECTIVES: To clarify the effects of c-Myc inhibition in CML, we examined the anti-tumor property of a well-known small molecule inhibitor of c-Myc 10058-F4 on K562 cell line. METHODS: This experimental study was conducted in K562 cell line for evaluation of cytotoxic activity of 10058-F4 using Trypan blue and MTT assays. Flow cytometry and Quantitative RT-PCR analysis were also conducted to determine its mechanism of action. Additionally, Annexin/PI staining was performed for apoptosis assessment. RESULTS: The results of Trypan blue and MTT assay demonstrated that inhibition of c-Myc, as shown by suppression of c-Myc expression and its associated genes PP2A, CIP2A, and hTERT, could decrease viability and metabolic activity of K562 cells, respectively. Moreover, a robust elevation in cell population in G1-phase coupled with up-regulation of p21 and p27 expression shows that 10058-F4 could hamper cell proliferation, at least partly, through induction of G1 arrest. Accordingly, we found that 10058-F4 induced apoptosis via increasing Bax and Bad; In contrast, no significant alterations were observed NF-KB pathway-targeted anti-apoptotic genes in the mRNA levels. Notably, disruption of the NF-κB pathway with bortezomib as a common proteasome inhibitor sensitized K562 cells to the cytotoxic effect of 10058-F4, substantiating the fact that the NF-κB axis functions probably attenuate the K562 cells sensitivity to c-Myc inhibition. CONCLUSIONS: It can be concluded from the results of this study that inhibition of c-Myc induces anti-neoplastic effects on CML-derived K562 cells as well as increases the efficacy of imatinib. For further insight into the safety and effectiveness of 10058-F4 in CML, in vivo studies will be required.

GINS1 promotes the initiation and progression of bladder cancer by activating the AKT/mTOR/c-Myc signaling pathway.

Bladder cancer(BC) is one of the most prevalent cancers in the urinary tract, with high recurrence and fatality rates. Research indicates that go-ichi-ni-san complex subunit 1 (GINS1) crucially influences cancer progression by regulating DNA replication through cell cycle modulation. Thus, suppressing the active proliferation of cells in tumor tissues may require silencing GINS1. However, the consequences of GINS1 in bladder cancer aren't to be determined. In this paper, we examine the role and mechanism of GINS1 in the development of bladder cancer. GINS1 expression levels and prognostic relevance in bladder cancer were validated using Western blotting, immunohistochemistry, and Kaplan-Meier survival analysis. The influence of GINS1 on bladder cancer was investigated using a variety of approaches, including cell transfection, cell counts, transwell migrations, colony formation, and flow cytometry. Immunohistochemistry studies demonstrate that GINS1 expression is increased in bladder cancer tissues. GINS1 silencing resulted in an arrest of the cell cycle at the phase of G0/G1, which inhibited BC cell growth both in vitro and in vivo. GINS1 knockdown also hindered the AKT/mTOR pathway. Furthermore, increased GINS1 expression affects the cell cycle and stimulates the AKT/mTOR pathway, allowing BC to develop more quickly. Consequently, GINS1 occurs as a latent therapeutic target, particularly for individuals with BC.

Transcriptional Up-Regulation of FBXW7 by KCa1.1 K+ Channel Inhibition through the Nrf2 Signaling Pathway in Human Prostate Cancer LNCaP Cell Spheroid Model.

The tumor suppressor gene F-box and WD repeat domain-containing (FBXW) 7 reduces cancer stemness properties by promoting the protein degradation of pluripotent stem cell markers. We recently demonstrated the transcriptional repression of FBXW7 by the three-dimensional (3D) spheroid formation of several cancer cells. In the present study, we found that the transcriptional activity of FBXW7 was promoted by the inhibition of the Ca2+-activated K+ channel, KCa1.1, in a 3D spheroid model of human prostate cancer LNCaP cells through the Akt-Nrf2 signaling pathway. The transcriptional activity of FBXW7 was reduced by the siRNA-mediated inhibition of the CCAAT-enhancer-binding protein C/EBP δ (CEBPD) after the transfection of miR223 mimics in the LNCaP spheroid model, suggesting the transcriptional regulation of FBXW7 through the Akt-Nrf2-CEBPD-miR223 transcriptional axis in the LNCaP spheroid model. Furthermore, the KCa1.1 inhibition-induced activation of FBXW7 reduced (1) KCa1.1 activity and protein levels in the plasma membrane and (2) the protein level of the cancer stem cell (CSC) markers, c-Myc, which is a molecule degraded by FBXW7, in the LNCaP spheroid model, indicating that KCa1.1 inhibition-induced FBXW7 activation suppressed CSC conversion in KCa1.1-positive cancer cells.

Pirfenidone Reverts Global DNA Hypomethylation, Promoting DNMT1/UHRF/PCNA Coupling Complex in Experimental Hepatocarcinoma.

Hepatocellular carcinoma (HCC) development is associated with altered modifications in DNA methylation, changing transcriptional regulation. Emerging evidence indicates that DNA methyltransferase 1 (DNMT1) plays a key role in the carcinogenesis process. This study aimed to investigate how pirfenidone (PFD) modifies this pathway and the effect generated by the association between c-Myc expression and DNMT1 activation. Rats F344 were used for HCC development using 50 mg/kg of diethylnitrosamine (DEN) and 25 mg/kg of 2-Acetylaminofluorene (2-AAF). The HCC/PFD group received simultaneous doses of 300 mg/kg of PFD. All treatments lasted 12 weeks. On the other hand, HepG2 cells were used to evaluate the effects of PFD in restoring DNA methylation in the presence of the inhibitor 5-Aza. Histopathological, biochemical, immunohistochemical, and western blot analysis were carried out and our findings showed that PFD treatment reduced the amount and size of tumors along with decreased Glipican-3, ß-catenin, and c-Myc expression in nuclear fractions. Also, this treatment improved lipid metabolism by modulating PPARγ and SREBP1 signaling. Interestingly, PFD augmented DNMT1 and DNMT3a protein expression, which restores global methylation, both in our in vivo and in vitro models. In conclusion, our results suggest that PFD could slow down HCC development by controlling DNA methylation.

Mechanisms Underlying the Development of Murine T-Cell Lymphoblastic Lymphoma/Leukemia Induced by Total-Body Irradiation.

Exposure to ionizing radiation is associated with an increased risk of hematologic malignancies in myeloid and lymphoid lineages in humans and experimental mice. Given that substantial evidence links radiation exposure with the risk of hematologic malignancies, it is imperative to deeply understand the mechanisms underlying cellular and molecular changes during the latency period between radiation exposure and the emergence of fully transformed malignant cells. One experimental model widely used in the field of radiation and cancer biology to study hematologic malignancies induced by radiation exposure is mouse models of radiation-induced thymic lymphoma. Murine radiation-induced thymic lymphoma is primarily driven by aberrant activation of Notch signaling, which occurs frequently in human precursor T-cell lymphoblastic lymphoma (T-LBL) and T-cell lymphoblastic leukemia (T-ALL). Here, we summarize the literature elucidating cell-autonomous and non-cell-autonomous mechanisms underlying cancer initiation, progression, and malignant transformation in the thymus following total-body irradiation (TBI) in mice.

Interplay between mTOR and Purine Metabolism Enzymes and Its Relevant Role in Cancer.

Tumor cells reprogram their metabolism to meet the increased demand for nucleotides and other molecules necessary for growth and proliferation. In fact, cancer cells are characterized by an increased "de novo" synthesis of purine nucleotides. Therefore, it is not surprising that specific enzymes of purine metabolism are the targets of drugs as antineoplastic agents, and a better knowledge of the mechanisms underlying their regulation would be of great help in finding new therapeutic approaches. The mammalian target of the rapamycin (mTOR) signaling pathway, which is often activated in cancer cells, promotes anabolic processes and is a major regulator of cell growth and division. Among the numerous effects exerted by mTOR, noteworthy is its empowerment of the "de novo" synthesis of nucleotides, accomplished by supporting the formation of purinosomes, and by increasing the availability of necessary precursors, such as one-carbon formyl group, bicarbonate and 5-phosphoribosyl-1-pyrophosphate. In this review, we highlight the connection between purine and mitochondrial metabolism, and the bidirectional relation between mTOR signaling and purine synthesis pathways.

[Amplifiation of the c-MYC gene in acinar prostate adenocarcinoma. Morphogenic comparisons]. / Amplifikatsiya gena c-MYC pri atsinarnoi adenokartsinome prostaty. Morfogeneticheskie sopostavleniya.

OBJECTIVE: The purpose of this work was to evaluate c-MYC gene amplification in the substrate of prostate acinar adenocarcinoma at various Gleason scores and various stages of the disease, taking into account the morphological characteristics of the tumor. MATERIAL AND METHODS: The number of cases in the study was 82, including the control group - 12 cases. Morphological assessment included: determination of the total Gleason score, grading group, assessment of lymphovascular/perineural invasion, and architectural characteristics of the tumor. Gene amplification was assessed by FISH using the c-MYC (8q24)/SE8 probe. RESULTS: In all cases of the study group, amplification of the c-MYC gene was detected in the tumor, with a significant difference from the control group (p<0.05). When assessing cases with 4-6 fold copies of the gene, significant differences were established between patients with stages II and III of the disease and stage IV (10.0 and 13.5 versus 30.0) (p<0.05). Cluster amplification of the c-MYC gene was detected with equal frequency in groups of patients with stages III and IV of the disease, while in stage II of the disease, the event almost did not occur (p<0.05). A significant increase in the level of c-MYC gene amplification was found in groups with advanced stages of the disease (p<0.02). Non-cluster amplification significantly distinguishes T4M0 and T4M1 stage patients from the rest with a significant increase in the score (p<0.05). In the metastatic stage of the disease, there was an increase c-MYC gene amplification compared to the non-metastatic stage (p<0.02). The copy number of the c-MYC gene was significantly higher in cases with perineural and lymphovascular invasion, as well as in cases of cribriform tumor organization (p<0.05). CONCLUSION: Amplification of the c-MYC gene in prostate tumor cells is associated with advanced stages of the disease (T4M0 and T4M1) with an increase in the copy number of the gene during the metastatic stage of the process. It was found that increased amplification of the c-MYC gene distinguishes groups of patients whose tumors exhibit perineural and lymphovascular invasion, as well as a cribriform pattern of tumor organization.

The mechanism of RGS5 regulating gastric cancer mismatch repair protein.

The incidence and mortality rates of gastric cancer (GC) remain alarmingly high worldwide, imposing a substantial healthcare burden. In this study, we utilized data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A 4-gene prognostic model was developed to predict patient prognosis, and its accuracy was validated across multiple datasets. Patients with a low-risk score exhibited improved prognosis, elevated tumor mutation burden, heightened sensitivity to both immunotherapy and conventional chemotherapy. Notably, our investigation revealed that the key gene RGS5 positively modulates the expression of mismatch repair proteins via c-Myc. Furthermore, co-immunoprecipitation (COIP) assays demonstrated the interaction between RGS5 and c-Myc. Additionally, we confirmed that RGS5 regulates c-Myc through the ubiquitin-proteasome pathway. Moreover, RGS5 was identified as a positive regulator of PD-L1 expression and exhibited a negative correlation with the majority of immune cells. These findings underscore the potential of RGS5 as a novel biomarker and therapeutic target in the context of GC.

Implications of c-Myc in the pathogenesis and treatment efficacy of urological cancers.

Urological cancers, including prostate, bladder, and renal cancers, are significant causes of death and negatively impact the quality of life for patients. The development and progression of these cancers are linked to the dysregulation of molecular pathways. c-Myc, recognized as an oncogene, exhibits abnormal levels in various types of tumors, and current evidence supports the therapeutic targeting of c-Myc in cancer treatment. This review aims to elucidate the role of c-Myc in driving the progression of urological cancers. c-Myc functions to enhance tumorigenesis and has been documented to increase growth and metastasis in prostate, bladder, and renal cancers. Furthermore, the dysregulation of c-Myc can result in a diminished response to therapy in these cancers. Non-coding RNAs, ß-catenin, and XIAP are among the regulators of c-Myc in urological cancers. Targeting and suppressing c-Myc therapeutically for the treatment of these cancers has been explored. Additionally, the expression level of c-Myc may serve as a prognostic factor in clinical settings.

Collaboration of Hprt/K-RAS/c-Myc mutation in the oncogenesis of T-lymphocytic leukemia: a comparative study.

Aim: Leukemia is a malignant clonal illness stem from the mutations of hematopoietic cells. Acute lymphoblastic leukemia is one of the utmost prevalent kinds of leukemia, is brought on by atypical lymphoid progenitor cell division in the bone marrow. Materials & methods: A comparative study between, titanium Nanoparticle-loaded doxorubicin or cisplatin and lactoferrin-loaded doxorubicin or cisplatin, on 7,12-dimethylbenz[a]-anthracene (DMBA)-induced leukemia was investigated and confirming the hypothesis that messenger RNA of Hprt/K-RAS/c-Myc/SAT-2/P53/JAK-2 is a forthcoming signaling pathways in leukemia. Results: A significant alteration in Hprt, K-RAS, C-Myc, P53, JAK-2 and SAT-2 genes was observed post DMBA intoxication the aforementioned Nanodrugs modulated these signaling pathways. Conclusion: The carrier-loaded drugs triggered cytotoxicity of cancer cells via enhancing drug efficacy and bio-availability.

Leukemia is the abnormal growth of white blood cells that is responsible for fighting infection. Cisplatin and doxorubicin are commonly used anticancer drugs that can combat leukemic cells however they faced some problems of poor solubility and toxicity to normal cells. Thus we designed nanodrugs as Ti-NPs-cisplatin or DOX and lactoferrin-cisplatin or DOX and compared them with DOX and cisplatin and studied their impact on DMBA-induced leukemia in rat models. Monitoring apoptotic and cell survival genes was performed. Treatment with the nanodrugs could be promising in targeting cancer cells and improving drug bio-availability thus inducing cancer cell death.

Titanium dioxide nanostructure-loaded Adriamycin surmounts resistance in breast cancer therapy: ABCA/P53/C-myc crosstalk.

Aim: To clarify the alternation of gene expression responsible for resistance of Adriamycin (ADR) in rats, in addition to investigation of a novel promising drug-delivery system using titanium dioxide nanoparticles loaded with ADR (TiO2-ADR). Method: Breast cancer was induced in female Sprague-Dawley rats, followed by treatment with ADR (5 mg/kg) or TiO2-ADR (2 mg/kg) for 1 month. Results: Significant improvements in both zinc and calcium levels were observed with TiO2-ADR treatment. Gene expression of ATP-binding cassette transporter membrane proteins (ABCA1 & ABCG1), P53 and Jak-2 showed a significant reduction and overexpression of the C-myc in breast cancer-induced rats. TiO2-ADR demonstrated a notable ability to upregulate these genes. Conclusion: TiO2-ADR could be a promising drug-delivery system for breast cancer therapy.

The current study aimed to investigate a novel and promising drug-delivery system to overcome the resistance problem by loading Adriamycin (ADR) into titanium dioxide nanoparticles (TiO₂). The study also aimed to clarify the changes in gene expression responsible for the development of ADR resistance, in a rat model. First, animals were divided into four groups of ten each. Breast cancer was induced in female Sprague-Dawley rats by administering two doses of DMBA (50 and 25 mg/kg), followed by treatment with ADR at a dose of 5 mg/kg for 1 month, or TiO₂-ADR at a dose of 2 mg/kg for 1 month. Biochemical and molecular analyses were conducted. Zinc and calcium levels were found to significantly decrease after cancer induction. Treatment with ADR alone or in combination with TiO₂ showed a significant improvement in both mineral levels, with the TiO₂-ADR group showing superior results. Gene expression of ATP-binding cassette transporter membrane proteins (ABCA1 & ABCG1), P53 and Jak-2 showed a significant decrease after DMBA-induced breast cancer. However, both the ADR- and TiO₂-ADR-treated groups showed a notable increase in gene expression, with the TiO₂-ADR group showing the highest increase. On the other hand, there was a significant overexpression of the C-myc gene after DMBA-induced breast cancer. However, both ADR and TiO₂-ADR treatments resulted in a notable decrease in C-myc gene expression. Based on the data, TiO₂-ADR could be a promising drug-delivery system for breast cancer therapy.

In silico and in vivo analysis reveal impact of c-Myc tag in FMC63 scFv-CD19 protein interface and CAR-T cell efficacy.

Anti-CD19 CAR-T cell therapy represents a breakthrough in the treatment of B-cell malignancies, and it is expected that this therapy modality will soon cover a range of solid tumors as well. Therefore, a universal cheap and sensitive method to detect CAR expression is of foremost importance. One possibility is the use of epitope tags such as c-Myc, HA or FLAG tags attached to the CAR extracellular domain, however, it is important to determine whether these tags can influence binding of the CAR with its target molecule. Here, we conducted in-silico structural modelling of an FMC63-based anti-CD19 single-chain variable fragment (scFv) with and without a c-Myc peptide tag added to the N-terminus portion and performed molecular dynamics simulation of the scFv with the CD19 target. We show that the c-Myc tag presence in the N-terminus portion does not affect the scFv's structural equilibrium and grants more stability to the scFv. However, intermolecular interaction potential (IIP) analysis reveals that the tag can approximate the complementarity-determining regions (CDRs) present in the scFv and cause steric impediment, potentially disturbing interaction with the CD19 protein. We then tested this possibility with CAR-T cells generated from human donors in a Nalm-6 leukemia model, showing that CAR-T cells with the c-Myc tag have overall worse antitumor activity, which was also observed when the tag was added to the C-terminus position. Ultimately, our results suggest that tag addition is an important aspect of CAR design and can influence CAR-T cell function, therefore its use should be carefully considered.

Gene expression profiling of p53 and c-myc in HTLV-1 positive blood donors in Congo.

OBJECTIVES: The HTLV-1 infection persists for life, remaining as asymptomatic viral reservoirs in most patients, ensuring the chain of transmission, but around 4% develop adult T-cell leukemia/lymphoma (ATLL). HTLV-1 is an oncogenic retrovirus that transforms CD4+ T lymphocytes and deregulates the lymphoproliferative pathways that contribute to the development of ATLL. To achieve cell transformation, most oncogenic retroviruses use proto-oncogene capture transduction, with proviral integration disrupting the expression of tumor suppressors or proto-oncogenes. THE AIM: We conducted this study on the prevalence of HTLV-1 infection in blood donors to expand the HTLV-1 database, assess the risk of transmission via blood products, as well as evaluate the risk of persistent infection or development of neoplastic diseases in HTLV-1 carriers. MATERIALS AND METHODS: This is a cross-sectional study of blood donors of all categories. For this study, 265 blood donors were recruited at the Centre National de Transfusion Sanguine in Brazzaville. After testing for HTLV-1 antibodies by ELISA, proviral DNA was extracted from all ELISA-positive samples for detection by nested PCR, followed by RT qPCR using specific primers p53 and c-myc for gene expression. RESULTS: 20/265 were positive for anti-HTLV-1 antibody, 5 donors were positive for proviral DNA. The prevalence of HTLV-1 was 1.8%. All HTLV-1-positive donors were male (1.8%), with a positive correlation (p = 0.05); the 1.1% of positive donors were regular, with the majority aged between 31 and 45 years (1.5%), and concubine donors were the most frequent (1.1%). All samples showed normal expression of the p53 and c-myc genes. CONCLUSION: The prevalence, though low, remains a serious problem. No abnormal p53 or c-myc gene expression was detected in HTLV-1-positive donors, which could mean that none of the T lymphocytes in these donors had been transformed by HTLV-1.

SIRT4 Has an Anti-Cancer Role in Cervical Cancer by Inhibiting Glutamine Metabolism via the MEK/ERK/C-Myc Axis.

BACKGROUND/AIM: Glutamine metabolism is crucial in cell proliferation, aging, and apoptosis across various cancer types. Existing research indicates that Sirtuin 4 (SIRT4), primarily located in mitochondria, modulates this process. This study aimed to clarify the regulatory relationship between SIRT4 and glutamine metabolism in cervical cancer. MATERIALS AND METHODS: SIRT4 mRNA levels and their clinical correlation to cervical cancer were analyzed using the UALCAN database. Immunohistochemistry (IHC) was performed to assess SIRT4 protein expression in tissue samples from cervical cancer patients. Transient transfection was employed to create Hela and Siha cell lines with overexpressed SIRT4, mitogen-activated extracellular signal-regulated kinase (MEK), and glutaminase 1 (GLS1). The impact on cellular functions was studied using MTT, soft agar, transwell, and western blotting assays. Glutamate and ATP levels were also measured to evaluate metabolic changes. RESULTS: Low levels of SIRT4 mRNA in cervical cancer tissues correlated with tumor metastasis and poor survival rates. Overexpression of SIRT4 led to suppressed cell proliferation, colony growth, and motility, along with significant down-regulation of GLS expression, a key contributor to glutamine metabolism. Additionally, SIRT4 overexpression resulted in the inactivation of the MEK/ERK/c-myc signaling pathway, while overexpression of MEK reversed these effects. Notably, the inhibitory effects of SIRT4 on cell proliferation, colony formation, migration, and invasion in Hela and Siha cells were significantly attenuated following GLS1 overexpression. CONCLUSION: SIRT4 acts as an anti-cancer agent in cervical cancer by inhibiting glutamine metabolism through the MEK/ERK/c-myc signaling pathway, providing a novel sight for cervical cancer therapy.

Reduced Malignancy of Super Methotrexate-resistant Osteosarcoma Cells With Dihydrofolate Reductase Amplification Despite Paradoxical Gain of Oncogenic PI3K/AKT/mTOR and c-MYC expression.

BACKGROUND/AIM: Methotrexate (MTX) resistance in osteosarcoma leads to a very poor prognosis. In the present study, in order to further understand the basis and ramifications of MTX resistance in osteosarcoma, we selected an osteosarcoma cell line that has a 5,500-fold-increased MTX IC50 Materials and Methods: The super MTX-resistant 143B osteosarcoma cells (143B-MTXSR) were selected from MTX-sensitive parental human 143B osteosarcoma cells (143B-P) by continuous culture with step-wise increased amounts of MTX. To compare the malignancy of 143B-MTXSR and 143B-P, colony-formation capacity was compared with clonogenic assays on plastic and in soft agar. In addition, tumor growth was compared with orthotopic xenograft mouse models of osteosarcoma. Expression of dihydrofolate reductase (DHFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), and myelocytomatosis oncogene (MYC) was examined with western immunoblotting and compared in 143B-MTXSR and 143B-P cells. RESULTS: 143B-MTXSR had a 5,500-fold increase in the MTX IC50 compared to the parental 143B-P cells. Expression of DHFR was increased 10-fold in 143B-MTXSR compared to 143B-P (p<0.01). 143B-MTXSR cells had reduced colony-formation capacity on plastic (p=0.032) and in soft agar (p<0.01) compared to 143B-P and reduced tumor growth in orthotopic xenograft mouse models (p<0.001). These results demonstrate that 143B-MTXSR had reduced malignancy. 143B-MTXSR also showed an increased expression of PI3K (p<0.01), phosphorylated (activated) AKT (p=0.031), phosphorylated mTOR (p=0.043), and c-MYC (p=0.024) compared to 143B-P. CONCLUSION: The present study demonstrates that the increased expression of DHFR, PI3K/AKT/mTOR and c-MYC appears to be linked to super MTX resistance and, paradoxically, to reduced malignancy. The present results suggest that DHFR may be a powerful tumor suppressor when highly amplified.