Inhibited Cell Growth Research Articles

Enhancing efficacy of the MEK inhibitor trametinib with paclitaxel in KRAS -mutated colorectal cancer.

KRAS is frequently mutated in the tumors of patients with metastatic colorectal cancer (mCRC) and thus represents a valid target for therapy. However, the strategies of targeting KRAS directly and targeting the downstream effector mitogen-activated protein kinase kinase (MEK) via monotherapies have shown limited efficacy. Thus, there is a strong need for novel, effective combination therapies to improve MEK-inhibitor efficacy in patients with KRAS -mutated mCRC. Our objective was to identify novel drug combinations that enhance MEK-inhibitor efficacy in patients with KRAS -mutated mCRC. In this study, we performed unbiased high-throughput screening (HTS) to identify drugs that enhance the efficacy of MEK inhibitors in vitro , and we validated the efficacy of the drugs in vivo . HTS was performed using 3-dimensional CRC spheroids. Trametinib, the anchor drug, was probed with 2 clinically ready libraries of 252 drugs to identify effective drug combinations. The effects of the drug combinations on CRC cell proliferation and apoptosis were further validated using cell growth assays, flow cytometry, and biochemical assays. Proteomic and immunostaining studies were performed to determine the effects of the drugs on molecular signaling and cell division. The effects of the drug combinations were examined in vivo using CRC patient-derived xenografts. HTS identified paclitaxel as being synergistic with trametinib. In vitro validation showed that, compared with monotherapies, this drug combination demonstrated strong inhibition of cell growth, reduced colony formation, and enhanced apoptosis in multiple KRAS -mutated CRC cell lines. Mechanistically, combining trametinib with paclitaxel led to alterations in signaling mediators that block cell cycle progression and increases in microtubule stability that resulted in significantly higher defects in the mitosis. Finally, the combination of trametinib with paclitaxel exhibited significant inhibition of tumor growth in several KRAS -mutant patient-derived xenograft mouse models. Our data provide evidence supporting clinical trials of trametinib with paclitaxel as a novel therapeutic option for patients with KRAS -mutated, metastatic CRC.

Synthesis and Biological Evaluation of Novel Furopyridone Derivatives as Potent Cytotoxic Agents against Esophageal Cancer.

Cancer continues to be a major global health issue, ranking among the top causes of death worldwide. To develop novel antitumor agents, this study focused on the synthesis of a series of 21 novel furanopyridinone derivatives through structural modifications and functional enhancements. The in vitro anti-tumor activities of these compounds were investigated through the cytotoxicity against KYSE70 and KYSE150 and led to the identification of compound 4c as the most potent compound. At a concentration of 20 µg/mL, compound 4c demonstrated a remarkable 99% inhibition of KYSE70 and KYSE150 cell growth after 48 h. IC50 was 0.655 µg/mL after 24 h. Additionally, potential anti-tumor cellular mechanisms were explored through molecular docking, which was used to predict the binding mode of 4c with METAP2 and EGFR, suggesting that the C=O part of the pyridone moiety likely played a crucial role in binding. This study provided valuable insights and guidance for the development of novel anticancer drugs with novel structural scaffolds.

Enhanced anti-tumor and anti-metastatic activity of quercetin using pH-sensitive Alginate@ZIF-8 nanocomposites:in vitroandin vivostudy.

Quercetin (Qc) possesses anti-cancer properties, such as cell signaling, growth suppression, pro-apoptotic, anti-proliferative, and antioxidant effects. In this study, we developed an alginate-modified ZIF-8 (Alg@ZIF-8) to enhance the anti-tumor efficacy of Qc. The developed alginate-modified quercetin-loaded ZIF-8 (Alg@Qc@ZIF-8) was characterized using scanning electron microscope (SEM), dynamic light scattering (DLS), fourier transform infrared spectroscopy Thermogravimetric analysis, Brunauer-Emmett-Teller, and x-ray diffraction. The drug release pattern was evaluated at pH 5.4 and 7.4. The cytotoxicity of nanoparticles was assessed on the 4T1 cell line. Finally, the anti-tumor activity of Alg@Qc@ZIF-8 was evaluated in 4T1 tumor-bearing mice. SEM showed that the nanoparticles were spherical with a diameter of mainly below 50 nm. The DLS showed that the developed nanoparticles' hydrodynamic diameter, zeta potential, and polydispersity index were 154.9 ± 7.25 nm, -23.8 ± 5.33 mV, and 0.381 ± 0.09, respectively. The drug loading capacity was 10.40 ± 0.02%. Alg@Qc@ZIF-8 exhibited pH sensitivity, releasing more Qc at pH 5.4 (about 3.62 times) than at pH 7.4 after 24 h. Furthermore, the IC50value of Alg@Qc@ZIF-8 on the 4T1 cell line was 2.16 times lower than net Qc. Importantly, in tumor-bearing mice, Alg@Qc@ZIF-8 demonstrated enhanced inhibitory effects on tumor growth and lung metastasis compared to net Qc. Considering thein vitroandin vivooutcomes, Alg@Qc@ZIF-8 might hold great potential for effective breast cancer management.

Undescribed Amaryllidaceae Alkaloids from Zephyranthes citrina and Their Cytotoxicity.

This phytochemical study presents the isolation of eight alkaloids from Zephyranthes citrina Baker. The structures of the new alkaloids, zephycitrine (1) and 6-oxonarcissidine (2), were established by analysis of spectroscopic and spectrometric data. Processing the EtOH extract under acid-base conditions yielded the unreported isolation artifacts 3 and 4. This work also provides analytical data for alkaloids not properly described in the literature (5 and 6). The hippeastidine/zephyranine scaffolds in derivatives 3, 4, and 8-10 are also thoroughly discussed. Furthermore, a cytotoxicity screening of 25 Amaryllidaceae alkaloids isolated from Z. citrina was performed. Only the known alkaloids haemanthamine (12), haemanthidine (13), and lycorine (27) showed significant cell growth inhibition.

FUT6 Suppresses the Proliferation, Migration, Invasion, and Epithelial-Mesenchymal Transition of Esophageal Carcinoma Cells via the Epidermal Growth Factor Receptor/Extracellular Signal-Regulated Kinase Signaling Pathway.

Esophageal cancer (ESCA) is a high-incidence disease worldwide, of which the 5-year survival rate remains dismal since the cellular basis of ESCA remains largely unclear. Herein, we attempted to examine the manifestation of fucosyltransferase-6 (FUT6) in ESCA and the associated mechanisms. The GSE161533 dataset was used to analyze a crucial gene in ESCA. The expression of FUT6 was investigated in normal esophageal epithelial cells and ESCA cell lines. Following FUT6 knockdown or overexpression, cell proliferation, migration, invasion, and levels of epithelial–mesenchymal transition (EMT)-related and epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) signaling pathway-related proteins were evaluated using CCK-8, Transwell, and Western blotting with antibodies against EGFR, p-EGFR, E-cadherin, Vimentin, N-cadherin, ERK1/2, and p-ERK1/2), respectively. EGF was administered to stimulate the EGFR/ERK signaling pathway, followed by the assessment of cellular activity. Database analysis revealed that FUT6 was downregulated in the ESCA cells. Our study indicated that FUT6 is suppressed in various ESCA cell lines. Moreover, cell proliferation, invasion, migration, and EMT-related protein levels were conspicuously enhanced or restrained by FUT6 disruption or overexpression. FUT6 overexpression suppressed the malignant activities of the cells when stimulated by EGF, including inhibition of cell growth, movement, invasion, and EMT advancement, as well the reduction the levels of EGFR/ERK pathway proteins. In conclusion, FUT6 can suppress the EGFR/ERK signaling pathway activated by EGF, leading to the potential attenuation of ESCA cell proliferation, invasion, migration, and EMT.

Programming DNA Nanoassemblies into Polyvalent Lysosomal Degraders for Potent Degradation of Pathogenic Membrane Proteins.

Lysosome-targeting chimera (LYTAC) shows great promise for protein-based therapeutics by targeted degradation of disease-associated membrane or extracellular proteins, yet its efficiency is constrained by the limited binding affinity between LYTAC reagents and designated proteins. Here, we established a programmable and multivalent LYTAC system by tandem assembly of DNA into a high-affinity protein degrader, a heterodimer aptamer nanostructure targeting both pathogenic membrane protein and lysosome-targeting receptor (insulin-like growth factor 2 receptor, IGF2R) with adjustable spatial distribution or organization pattern. The DNA-based multivalent LYTACs showed enhanced efficacy in removing immune-checkpoint protein programmable death-ligand 1 (PD-L1) and vascular endothelial growth factor receptor 2 (VEGFR2) in tumor cell membrane that respectively motivated a significant increase in T cell activity and a potent effect on cancer cell growth inhibition. With high programmability and versatility, this multivalent LYTAC system holds considerable promise for realizing protein therapeutics with enhanced activity.

RETRACTION:Increased expression of LGI1 gene triggers growth inhibition and apoptosis of neuroblastoma cells.

N. Gabellini, V. Masola, S. Quartesan, B. Oselladore, C. Nobile, R. Michelucci, M. Curtarello, C. Parolin, and G. Palù, Journal of Cellular Physiology 207, no. 3 (2006): 711-721. https://doi.org/10.1002/jcp.20627. The above article, published online on 03 March 2006, in Wiley Online Library (wileyonlinelibrary.com), and has been retracted by agreement between the journal Editor-in-Chief, Robert Heath; and Wiley Periodicals LLC. A third party reported that the GAPDH blots in Figure 1 and Figure 6 showed evidence of image manipulation. An investigation by the publisher found evidence of duplication, resizing, and splicing between Figures 1B and 6B as well as evidence of splicing in Figures 1A and 6A. The authors did not respond to an inquiry by the publisher and a request for original data. The retraction has been agreed to because the results presented in the article can no longer be considered reliable.

Synthesis and Molecular Dynamic Simulation of Novel Cationic and Non-cationic Pyrimidine Derivatives as Potential G-quadruplex-ligands.

Drug resistance has been a problem in cancer chemotherapy, which often causes shortterm effectiveness. Further, the literature indicates that telomere G-quadruplex could be a promising anti-cancer target. We synthesized and characterized two new pyrimidine derivatives as ligands for G-quadruplex DNA. The interaction of novel non-cationic and cationic pyrimidine derivatives (3a, b) with G-quadruplex DNA (1k8p and 3qsc) was explored by circular dichroism (CD) and ultraviolet-visible spectroscopy and polyacrylamide gel electrophoresis (PAGE) methods. The antiproliferative activity of desired compounds was evaluated by the MTT assay. Apoptosis induction was assessed by Propidium iodide (P.I.) staining and flow cytometry. Computational molecular modeling (CMM) and molecular dynamics simulation (MD) were studied on the complexes of 1k8p and 3qsc with the compounds. The van der Waals, electrostatic, polar solvation, solventaccessible surface area (SASA), and binding energies were calculated and analyzed. The experimental results confirmed that both compounds 3a and 3b interacted with 1k8p and 3qsc and exerted cytotoxic and proapoptotic effects on cancer cells. The number of hydrogen bonds and the RMSD values increased in the presence of the ligands, indicating stronger binding and suggesting increased structural dynamics. The electrostatic contribution to binding energy was higher for the cationic pyrimidine 3b, indicating more negative binding energies. Both experimental and MD results confirmed that 3b was more prone to form a complex with DNA G-quadruplex (1k8p and 3qsc), inhibit cell growth, and induce apoptosis, compared to the non-cationic pyrimidine 3a.

Targeting delivery of mifepristone to endometrial dysfunctional macrophages for endometriosis therapy

Endometriosis seriously affects 6–10 % of reproductive women globally and poses significant clinical challenges. The process of ectopic endometrial cell colonization shares similarities with cancer, and a dysfunctional immune microenvironment, characterized by non-classically polarized macrophages, plays a critical role in the progression of endometriosis. In this study, a targeted nano delivery system (BSA@Mif NPs) was developed using bovine serum albumin (BSA) as the carrier of mifepristone. The BSA@Mif NPs were utilized to selectively target M2 macrophages highly enriched in ectopic endometrial tissue via the SPARC receptor. This targeting strategy increases drug concentration at ectopic lesions while minimizing its distribution to normal tissue, thereby reducing side effects. In vitro studies demonstrated that BSA@Mif NPs not only enhanced the cellular uptake of M2-type macrophages and ectopic endometrial cells but also improved the cytotoxic effect of mifepristone on ectopic endometrial cells. Furthermore, the BSA@Mif NPs effectively induced immunogenic cell death (ICD) in ectopic endometrial cells and repolarized M2-type macrophages toward the M1 phenotype, resulting in a synergistic inhibition of ectopic endometrial cell growth. In vivo experiments revealed that BSA@Mif NPs exhibited significant therapeutic efficacy in endometriosis-bearing mice by increasing drug accumulation in the endometriotic tissues and modulating the immune microenvironment. This targeted biomimetic delivery strategy presents a promising approach for the development of endometriosis-specific therapies based on existing drugs. Statement of significanceMacrophages play an essential role in immune dysfunctional microenvironment promoting the occurrence and progression of endometriosis and can be a crucial target for developing immune microenvironment regulation strategies for the unmet long-term management of endometriosis. The albumin nanoparticles constructed based on SPARC overexpression in macrophages and endometrial cells and albumin biosafety can achieve the targeted therapy of endometriosis by increasing the passive- and active-mediated drug accumulation in ectopic endometrium and remodeling the immune microenvironment based on macrophage regulation. This study has the following implications: i) overcoming the inherent shortcomings of clinical drugs by nanotechnology is an alternative way of developing medication; ii) developing microenvironment modulation strategies based on macrophage regulation for endometriosis management is feasible.

Identification of sanguinarine as c-MYC transcription inhibitor through enhancing the G-quadruplex-NM23-H2 interactions

c-MYC is a proto-oncogene ubiquitously overexpressed in various cancers. The formation of G-quadruplex (G4) structures within the c-MYC promoter region can regulate its transcription by interfering with protein binding. Consequently, small molecules targeting c-MYC G4 have emerged as promising anticancer agents. Herein, we report that sanguinarine (SG) and its analogs exhibit a high affinity for c-MYC G4 and potently modulate G4-protein interactions within a natural product library. Notably, SG uniquely enhances NM23-H2 binding to c-MYC G4, both in vitro and in cellular contexts, leading to c-MYC transcriptional repression and subsequent inhibition of cancer cell growth in an NM23-H2-dependent manner. Mechanistic studies and molecular modeling suggest that SG binds to the c-MYC G4/NM23-H2 interface, acting as an orthosteric stabilizer of the DNA-protein complex and preventing c-MYC transcription. Our findings identify SG as a potent c-MYC transcription inhibitor and provide a novel strategy for developing G4-targeting anticancer therapeutics through modulation of G4-protein interactions.

CircZMYM2 plays a pivotal role in osteosarcoma by regulating the translation of NACA and ARPC1B

Osteosarcoma (OS) is a primary malignant bone tumor in children and young adults because of its intertumoral heterogeneity and absence of molecular targets. This study aimed to elucidate the role of circular RNA in the pathogenesis of OS. Using bioinformatics analysis and OS clinical samples, we found that hsa_circ_0029634 formed during the splicing process of Zinc finger MYM-type containing 2 (circZMYM2) was highly expressed in OS tissues. Nuclear cap-binding protein subunit 2 regulated circZMYM2 bio-generation by binding to flanking sequences of ZMYM2 transcripts. In addition, knockdown circZMYM2 inhibited cell growth and metastasis in OS cell lines in vitro and inhibited tumor growth in vivo. Mechanistically, circZMYM2 competitively bound to FXR1 to regulate the translation of NACA and ARPC1B. CircZMYM2 may be a crucial regulator of OS tumorigenesis and a potential diagnostic and therapeutic biomarker for OS patients.

Bioactive secondary metabolites from an endophytic fungus Aspergillus sp. CCH-1E from Catharanthus roseus

This study focused on the bioactive secondary metabolites of an endophytic fungus Aspergillus sp. CCH-1E from Catharanthus roseus. The secondary metabolites from Aspergillus sp. CCH-1E were isolated by using various chromatographic methods [such as normal-phase and reversed-phase chromatography and high-performance liquid chromatography(HPLC)], and their structures were identified by various spectroscopic methods [e.g., ultraviolet(UV) spectroscopy, infrared(IR) spectroscopy, nuclear magnetic resonance(NMR) spectroscopy, and high-resolution electrospray ionization mass spectrometry(HR-ESI-MS)]. Twelve compounds were yielded and identified from Aspergillus sp. CCH-1E, which are chermesinone H(1), chermesinone I(2), chermesinone B(3), 8,11-didehydrochermesinone B(4), chermesinone C(5), chermesinone A(6), chevalone B(7), barbacenic acid(8), 3,6,8-trihydroxy-3,5,7-trimethyl-3,4-dihydroisocoumarin(9), 5-hydroxy-2-methoxy-7-methyl-1,4-naphthoquinone(10), 1-hydroxy-6,8-dimethoxy-3-methylanthracene-9,10-dione(11), and 7-drimen-9α,11,12-triol(12). Among them, compounds 1 and 2 are new compounds. The growth inhibition effects of all compounds were evaluated against non-small cell lung cancer cell lines A549 and NCI-H1650, as well as human cervical cancer cell line HeLa by using methylthiazolyldiphenyl-tetrazolium bromide(MTT). Compound 7 significantly inhibited the growth of three tumor cells with the IC_(50) values of 1.22-2.43 μmol·L~(-1), respectively. Compounds 1-6 showed moderate cell growth inhibition with the IC_(50) values of 16.24-35.28 μmol·L~(-1).

Formulation and in-vitro anticancer activity of nilotinib immediate release and ibrutinib sustained release pellets

Background: Blood cancer is a significant contributor to mortality rates worldwide, and its prevalence is projected to rise on a global scale. This trend places considerable strain on healthcare systems and necessitates the expedited development of innovative treatments by pharmaceutical firms to remain competitive. Conventional pellets produce rapid plasma drug levels, but they might cause side effects, decrease effectiveness, and lead to poor therapeutic management. Ibrutinib and Nilotinib are employed to treat leukemia patients. Methodology: The current research aims to formulate, characterize, and anticancer effect of Nilotinib immediate release (NIR) and Ibrutinib sustained release (ISR) seal sugar-coated pellets. Micrometric properties estimated the characterization of the drug pellets, and surface morphology was estimated using scanning electron microscopy. Drug excipient compatibility studies, stability studies, and in-vitro drug release were accessed. Result & Discussion: The results of pellet formulations FNI-1 to FNI-5 showed that FNI-5 formulations showed 100±6.0 µm size and possessed excellent mechanical strength for giving pellets a good self-life; also, due to the higher drug content up to 99%, FNI-5 was the best suited for pellet formulation and because NIR showed 99.18 ± 2.12 drug release at 2h and ISR 99.03±3.74% up to 12h so that anticancer concentration maintained for prolonged period. The standard dose for cytotoxicity against the THP-1 cell line of Nilotinib was found to be 200 mg, and the maintenance oral dose of Ibrutinib was 140mg, with four times the intake of the drug up to 560 mg. In an in vitro study in FNI-5 (final formulation), the dose of Ibrutinib was reduced to 420 mg. Conclusion: A synergistic effect of Ibrutinib and nilotinib drugs was observed in the inhibition of cancer cell growth, with an IC50 value of 4.585 µg/mL

N6-methyladenosine enhances the expression of TGF-β-SMAD signaling family to inhibit cell growth and promote cell metastasis

TGF-β-SMAD signaling pathway plays an important role in the progression of various cancers. However, posttranscriptional regulation such as N6-methyladenosine (m6A) of TGF-β-SMAD signaling axis remains incompletely understood. Here, we reveal that insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) is low expression as well as associated with poor prognosis in clear cell renal cell carcinoma (ccRCC) patients and inhibits proliferation as well as promotes metastasis of ccRCC cells. Mechanistically, IGF2BP2 systematically regulates TGF-β-SMAD signaling family, including TGF-β1/2, TGF-βR1/2 and SMAD2/3/4, through mediating their mRNA stability in an m6A-dependent manner. Furthermore, the functional effects of IGF2BP2 on ccRCC cells is mediated by TGF-β-SMAD signaling downstream effector SMAD4, which is identified three m6A sites in 5′UTR and CDS. Our study establishes IGF2BP2-TGF-β-SMAD axis as a new regulatory effector in ccRCC, providing new insights for developing novel therapeutic strategies.

SZ-685C inhibits the growth of non-functioning pituitary adenoma by down-regulating miR-340-3p and inducing autophagy

BackgroundSZ-685C, an anthracycline compound derived from the mangrove endophytic fungus Halorosellinia sp. (No. 1403) collected from the South China Sea, has shown strong anticancer activities. Non-functioning pituitary adenomas (NFPAs) are a type of tumor that can be challenging to manage clinically and have a significant unmet medical need. Our research has found that SZ-685C showed an inhibitory effect on the viability, migration ability, and proliferation ability of a human non-functioning pituitary tumor-derived folliculostellate (PDFS) cell line. MethodsSZ-685C was prepared and purified from the mangrove endophytic fungus No. 1403. PDFS cells were exposed to SZ-685C, and the effect of SZ-685C on PDFS cells was evaluated. RNA sequencing was used to analyze the miRNA expression profile in PDFS cells of the control group and SZ-685C-treated group. Quantitative polymerase chain reaction (qPCR) was performed to verify the expression of selected miR-340-3p. The effects of SZ-685C on PDFS cells after overexpression of miR-340-3p were evaluated. Dual-luciferase reporter assays showed PPP1CB is a direct target of miR-340-3p. Finally, the action pathway of the selected miR-340-3p was predicted and evaluated through bioinformatics analysis. ResultsSZ-685C reduced cell viability in PDFS cells, accompanied by inhibition of migration ability and proliferation ability. The IC50 value for 24 h is 9.144 ± 0.991 μM, and for 48 h is 4.635 ± 0.551 μM. SZ-685C increased the protein levels of Beclin 1, the ratio of LC3-II to LC3-I, and LAMP-1, and down-regulated p62. MiRNA sequencing and further validation showed that miR-340-3p significantly decreased in PDFS cells treated with SZ-685C. After overexpression of miR-340-3p, the inhibition of viability, migration ability, proliferation ability, and autophagy-promoting effect of SZ-685C on PDFS cells were weakened. SZ-685C caused a decrease in PPP1CB expression and activation of the ERK pathway in PDFS cells, and this trend was reversed after overexpression of miR-340-3p. ConclusionsSZ-685C downregulates the expression of miR-340-3p in PDFS cells, thereby reducing the expression of PPP1CB and activating the ERK pathway to promote autophagic cell death, leading to inhibition of PDFS cell growth.

Nanosized Porphyrin-Containing Covalent Organic Polymer to Enhance Ferroptosis in Photodynamic Treatment of Tumor Cells via Glutathione Depletion.

A porphyrin-containing nanoscale covalent organic polymer (COP) was fabricated from 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and cystamine via an acylation reaction. On the one hand, TCPP can induce tumor cell death by laser irradiation. Due to the presence of disulfide bonds of cystamine which can react with glutathione, it exhibits depletion of glutathione and accumulation of peroxides in tumor cells. Ultimately by the hyaluronic acid to encapsulate the COP to get S-COP@HA, the nanoparticle with a size of 168.6 nm also exhibits good tumor accumulation and biosafety. Significant inhibition of tumor cell growth was observed after two consecutive doses of S-COP@HA at relatively low laser densities. This combination therapy was proved to reduce the level of reduced glutathione in tumor cells, where ferroptosis occurs after photodynamic treatment. Overall, this study presents a potent, good therapeutic option for the effective enhancement of photodynamic therapy by glutathione depletion.

Development of novel imipridone derivatives with potent anti-cancer activities as human caseinolytic peptidase P (hClpP) activators

Based on a clinically staged small molecular hClpP activator ONC201, a class of imipridone derivatives was designed and synthesized. These compounds were evaluated in a protease hydrolytic assay, as well as cell growth inhibition assays in three cancer cell lines, MIA PACA-2, HCT116, and MV4-11. A number of compounds that can more potently activate hClpP and more effectively inhibit cell growth in the three cancer cell lines than ONC201 were identified. The most potent compound, ZYZ-17, activated hClpP with an EC50 value of 0.24 µM and inhibited the growth of the three cancer cell lines with IC50 values of less than 10 nM. Mechanism studies for ZYZ-17 revealed that it potently activates cellular hClpP, efficiently induces the degradation of hClpP substrates, and robustly induces apoptosis in the three cancer cell lines. Furthermore, ZYZ-17 demonstrated a promising pharmacokinetic (PK) profile and exhibited highly potent in vivo antitumor activity in a pancreatic cancer MIA PACA-2 xenograft model in BALB/c nude mice.

A Non-Canonical p75HER2 Signaling Pathway Underlying Trastuzumab Action and Resistance in Breast Cancer.

Overexpression of HER2 occurs in 25% of breast cancer. Targeting HER2 has proven to be an effective therapeutic strategy for HER2-positive breast cancer. While trastuzumab is the most commonly used HER2 targeting agent, which has significantly improved outcomes, the overall response rate is low. To develop novel therapies to boost trastuzumab efficacy, it is critical to identify the mechanisms underlying trastuzumab action and resistance. We recently showed that the inhibition of breast cancer cell growth by trastuzumab is not through the inhibition of HER2 canonical signaling. Here we report the identification of a novel non-canonical HER2 signaling pathway and its interference by trastuzumab. We showed that HER2 signaled through a non-canonical pathway, regulated intramembrane proteolysis (RIP). In this pathway, HER2 is first cleaved by metalloprotease ADAM10 to produce an extracellular domain (ECD) that is released and the p95HER2 that contains the transmembrane domain (TM) and intracellular domain (ICD). p95HER2, if further cleaved by an intramembrane protease, γ-secretase, produced a soluble ICD p75HER2 with nuclear localization signal (NLS). p75HER2 is phosphorylated and translocated to the nucleus. Nuclear p75HER2 promotes cell proliferation. Trastuzumab targets this non-canonical HER2 pathway via inhibition of the proteolytic cleavage of HER2 by both ADAM10 and γ-secretase. However, p75HER2 pathway also confers resistance to trastuzumab once aberrantly activated. Combination of trastuzumab with ADAM10 and γ-secretase inhibitors completely blocks p75HER2 production in both BT474 and SKBR3 cells. We concluded that HER2 signals through the RIP signaling pathway that promotes cell proliferation and is targeted by trastuzumab. The aberrant HER2 RIP signaling confers resistance to trastuzumab that could be overcome by the application of inhibitors to ADAM10 and γ-secretase.

The effect of ribociclib on the expression levels of miR-141 and CDK4/6-USP51 signaling pathway genes in MCF-7 and MDA-MB-231 cells.

Patients with breast cancer, especially triple-negative breast cancer, have a poor prognosis. There is still no effective treatment for this disease. Due to resistance to traditional treatments such as chemotherapy and radiation therapy, there is a need to discover novel treatment strategies to treat this disease. Ribociclib is a selective CDK4/6 inhibitor. Approximately 20% of patients with HR+ breast cancer developed primary resistance to CDK4/6 inhibitors, and more than 30% experienced secondary resistance. Since most patients experience resistance during CDK4/6 inhibitor treatment, managing this disease is becoming more challenging. Many malignant tumors abnormally express microRNA (miR)-141, which participates in several cellular processes, including drug resistance, proliferation, epithelial-mesenchymal transition, migration, and invasion. In the present study, we cultured MDA-MB-231 and MCF-7 cells in DMEM-F12 medium. By performing MTT assay we determined the cytotoxic effects of ribociclib on breast cancer cells, as well as determining the IC50 of it. Then, we treated the cells with ribociclib at two time points: 24 h and 72 h. After that, RNA was isolated and reverse transcribed to cDNA. Finally, we performed qRT‒PCR to evaluate how ribociclib affects the expression level of desired genes. We found that ribociclib can inhibit cell growth in a dose- and time-dependent manner. We examined the mRNA expression of 4 genes. After ribociclib treatment, the mRNA expression of CDK6 and MYH10 decreased (p < 0.01, p < 0.05). The mRNA expression of CDON increased (p<0.05), but no significant changes were observed in ZEB1 mRNA expression. Furthermore, the qRT‒PCR results for miR-141 showed that the expression of miR-141 increased (p<0.01) after 72 h of treatment with ribociclib.

Apoptosis-Cell Cycle-Autophagy Molecular Mechanisms Network in Heterogeneous Aggressive Phenotype Prostate Hyperplasia Primary Cell Cultures Have a Prognostic Role.

Our study highlights the apoptosis, cell cycle, DNA ploidy, and autophagy molecular mechanisms network to identify prostate pathogenesis and its prognostic role. Caspase 3/7 expressions, cell cycle, adhesion glycoproteins, autophagy, nuclear shrinkage, and oxidative stress by flow-cytometry analysis are used to study the BPH microenvironment's heterogeneity. A high late apoptosis expression by caspases 3/7 activity represents an unfavorable prognostic biomarker, a dependent predictor factor for cell adhesion, growth inhibition by arrest in the G2/M phase, and oxidative stress processes network. The heterogeneous aggressive phenotype prostate adenoma primary cell cultures present a high S-phase category (>12%), with an increased risk of death or recurrence due to aneuploid status presence, representing an unfavorable prognostic biomarker, a dependent predictor factor for caspase 3/7 activity (late apoptosis and necrosis), and cell growth inhibition (G2/M arrest)-linked mechanisms. Increased integrin levels in heterogenous BPH cultures suggest epithelial-mesenchymal transition (EMT) that maintains an aggressive phenotype by escaping cell apoptosis, leading to the cell proliferation necessary in prostate cancer (PCa) development. As predictor biomarkers, the biological mechanisms network involved in apoptosis, the cell cycle, and autophagy help to establish patient prognostic survival or target cancer therapy development.