Growth Arrest In Cancer Cells Research Articles

Targeting telomerase with MST-312 leads to downregulation of CCND1, MDM2, MYC, and HSP90AA1 and induce apoptosis in Jurkat cell line.

Acute lymphoblastic leukemia is a challenging disease to treat, especially in older adults who are most commonly diagnosed and have a high risk of relapse, even with current treatment options. MST-312, targets the RNA component of telomerase, inhibiting its activity and leading to growth arrest and telomere shortening in cancer cells. This study aimed to investigate the effects of MST-312 on apoptosis rates and the expression of telomerase target genes, CCND1, MDM2, MYC, and HSP90AA1, in Jurkat cell line. Jurkat cell line was cultured and treated with various concentrations of MST-312(0 µM, 0.5 µM, 1 µM, 2 µM, and 4 µM). The optimal concentration of MST-312 was determined using MTT assay. Flow cytometry was employed to evaluate the apoptosis induced by MST-312 treatment. The expression levels of the target genes were measured using real-time polymerase chain reaction before and after the treatment with MST-312. P-value < 0.05 was considered statistically significant. The percentages of apoptotic cells after 48 h, as determined by flow cytometry analysis, were 30.32%, 52.35%, 57.60%, and 68.82%, respectively, compared to the control group which was 4.6%. The expression levels of all genes, including CCND1, MDM2, MYC, and HSP90AA1, were decreased compared to the control group. The results showed that MST-312 induced dose- and time-dependent apoptosis and downregulated the expression of CCND1, MDM2, MYC, and HSP90AA1in Jurkat cell line.

In vitro studies of the combination between berberine chloride and a Copper(II) complex against Triple negative breast cancer

In this study, the copper(II) complex [Cu(chromoneTSC)Cl2]•0·.5H2O•0.0625C2H5OH (where chromoneTSC = (E)-N-Ethyl-2-((4-oxo-4H-chromen-3-yl)methylene)-hydrazinecarbothioamide) was synthesized and characterized; then used to carry out in vitro studies in combination with berberine chloride (BBC). The ligand and complex were characterized by elemental analysis, FTIR and NMR (1H and 13C) spectroscopy, and conductivity measurements. The cytotoxic effect was analyzed by using the CCK-8 viability assay in cancer MDA-MB-231 VIM RFP and non-cancer MCF-10A cell lines. The IC50 values for the complex and BBC were 21.2 ± 1.6 and 48.3 ± 2.4 μM, respectively at 24 h incubation, while the IC50 value of the combination treatment was 9.3 ± 1.5 in cancer cells. The co-treatment group significantly increased the number of cells in G2 phase, indicating the growth arrest of cancer cells. Moreover, the combination group showed induction of both intrinsic and extrinsic apoptotic pathways. There was also a study on the effect of the combination treatment on receptor-interacting serine/threonine-protein kinase 3 (RIPK3) and mixed lineage kinase domain-like pseudokinase (MLKL) as biomarkers of necroptosis. The results showed activation of necroptosis after treatment with the combination of the copper complex and BBC via the activation of RIPK3–MLKL pathway.

ATXN3 functions as a tumor suppressor through potentiating galectin-9-mediated apoptosis in human colon adenocarcinoma

While the deubiquitinase ATXN3 has been implicated as a potential oncogene in various types of human cancers, its role in colon adenocarcinoma remains understudied. Surprisingly, our findings demonstrate that ATXN3 exerts an anti-tumor effect in human colon cancers through potentiating Galectin-9-induced apoptosis. CRISPR-mediated ATXN3 deletion unexpectedly intensified colon cancer growth both in vitro and in xenograft colon cancers. At the molecular level, we identified ATXN3 as a bona fide deubiquitinase specifically targeting Galectin-9, as ATXN3 interacted with and inhibited Galectin-9 ubiquitination. Consequently, targeted ATXN3 ablation resulted in reduced Galectin-9 protein expression, thereby diminishing Galectin-9-induced colon cancer apoptosis and cell growth arrest. The ectopic expression of Galectin-9 fully reversed the growth of ATXN3-null colon cancer in mice. Furthermore, immunohistochemistry staining revealed a significant reduction in both ATXN3 and Galectin-9 protein expression, along with a positive correlation between them in human colon cancer. Our study identifies the first Galectin-9-specific deubiquitinase and unveils a tumor-suppressive role of ATXN3 in human colon cancer.

Abstract 424: FDX2-KO induces global down-regulation of iron-sulfur cluster-containing proteins and senescence-like growth arrest or death in ovarian cancer cells

Abstract Iron-Sulfur clusters (Fe-S) are synthetized in mainly mitochondria and binds to various proteins (Fe-S proteins). Fe-S proteins play important roles in various cellular functions including energy metabolism, nucleic acid synthesis or redox homeostasis. However, roles of Fe-S clusters in cancer cells are not fully understood. Here, we report that loss of Fe-S biosynthesis causes proliferation arrest with DNA-damage response or cell death depend on TP53 status in ovarian cancer (OVC) cells. CRISPR-screening of all metabolism-related genes identified that Fe-S biosynthesis is essential for OVC proliferation. We chose one of the Fe-S biosynthesis factors, FDX2, and developed a cell line that can maintain FDX2 expression doxycycline (Dox) -dependently. In these cells, FDX2-loss induced irreversible growth arrest. FDX2-KO cells also showed enlarged and flatten morphology, up-regulation of SASP factors, and DNA damage through p53/p21 pathway activation. These were all senescence like phenotypes. To know these mechanisms, we performed proteome analysis and found that FDX2-loss caused global but differential post-transcriptional down-regulation of Fe-S proteins, in turn perturbing mitochondrial respiration, iron-regulation and redox homeostasis. These results all associated with DNA damage. Furthermore, we found that FDX2-KO induced caspase dependent cell death in TP53-KO condition instead of growth arrests. These results suggest that Fe-S cluster biosynthesis is significant in OVC proliferation and fate of FDX2-KO cells depends on TP53 status (senescence or cell death). FDX2 or Fe-S biosynthesis may be a new therapeutic target of OVC. Citation Format: Shuko Miyahara, Mai Ohuchi, Miyuki Nomura, Kayoko Hayashi, Muneaki Shimada, Nobuo Yaegashi, Nobuhiro Tanuma. FDX2-KO induces global down-regulation of iron-sulfur cluster-containing proteins and senescence-like growth arrest or death in ovarian cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 424.

Abstract 4185: Neutralizing human IFN-β combined with anti-human PD-L1 and anti-human CTLA-4 treatment increased control of endometrial tumor growth in a novel HLA-A matched BLT humanized mice

Abstract High concentrations of type I interferon can induce growth arrest and apoptosis in cancer cells upon acute exposure, while low concentrations of the same can provide significant pro-survival benefits upon chronic exposure. In vitro data show the dependence of cancer cells on self-generated IFN-I leads to their demise if the IFN-β gene is disrupted, but they manage to persist when provided with IFN-β from an external source. Importantly, murine models show that inhibition of myeloid-associated INF-β can limit tumor growth. As blockage of type I interferon can also restore the CD8+ T cell function after chronic viral infection, we sought to determine the effects of neutralizing anti-human IFN-β antibody 7859 (N-anti-IFN-β) when added to T-cell directed immunotherapy in BLT humanized mice implanted with HLA-A matched human endometrial cancer PDX specimens. Specifically, we tested the combination of immunotherapy with N-anti-IFN-β combined with anti-human PD-L1 and anti-human CTLA-4. N-anti-IFN-β was first characterized for neutralizing activity to confirm specific neutralization of IFNβ and not human IFN-β. HLA-A matched genotyped CD34 stem cells and thymus (BLT humanized mice) and clinical endometrial tumors (PDX) were joined in BLT humanized mice before infusions with N-anti-IFN-β with or without anti-human PD-L1 and anti-human CTLA-4, anti-human PD-L1 and anti-human CTLA-4 alone, and IgG control antibodies intraperitoneally twice per week over three weeks. Tumor sizes were measured weekly and weighted at the end of the study. Human leukocytes infiltrating PDX were assessed by IHC and flow cytometry. Leukocyte subset activation, exhaustion, and tumor-specific T-cell function were measured. Anti-human PD-L1 and anti-human CTLA-4 reduced tumor growth by 82.9% (p&amp;lt;0.0001), but quickly increased the T cell exhaustion markers PD-1 and LAG3. The addition of N-anti-IFN-β to immunotherapy significantly decreased the tumor growth rate by 96.2% (p&amp;lt;0.0001) also significantly different from immunotherapy alone (p=0.0009) N-anti-IFN-β monotherapy reduced tumor growth rate by 42.4% (p=0.0032). While there was an increase in infiltrating CD4 and CD8 T-cells in combination therapy, reductions in expression of PD-1 and LAG3 were observed when compared to immunotherapy or N-IFN-β groups alone Analysis was done with Prism software. The use of a novel HLA-A matched BLT humanized mice with human tumor PDX model shows that neutralization of IFN-β can increase the T-cell anti-tumor activity and tumor repression of immunotherapy with anti-human PD-L1 and anti-human CTLA-4 treatment. Citation Format: Zhe Yuan, Guorui Zu, Xiao Sun, Emmanouil Papasavvas, Lily Lu, Joel Cassel, Peter L. Lutes, Mark Cadungog, Joseph Salvino, Luis J. Montaner. Neutralizing human IFN-β combined with anti-human PD-L1 and anti-human CTLA-4 treatment increased control of endometrial tumor growth in a novel HLA-A matched BLT humanized mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4185.

Peptide mimetic NC114 induces growth arrest by preventing PKCδ activation and FOXM1 nuclear translocation in colorectal cancer cells.

The peptide mimetic, NC114, is a promising anticancer compound that specifically kills colorectal cancer cells without affecting normal colon epithelial cells. In our previous study, we observed that NC114 inhibited the Wnt/β-catenin pathway, with significant downregulation of both Ser 675-phosphorylated β-catenin and its target genes, cyclin D1 and survivin. However, the molecular mechanism responsible for its cytotoxic effect has not yet been fully characterized. In the present study, we demonstrated that NC114 prevented cell cycle progression from S to G2/M phase by downregulating cell cycle-related gene expression, and also induced growth arrest in SW480 and HCT-116 colorectal cancer cells. A novel covariation network analysis combined with transcriptome analysis revealed a series of signaling cascades affected by NC114 treatment, and identified protein kinase C-δ (PKCδ) and forkhead box protein M1 (FOXM1) as important regulatory factors for NC114-induced growth arrest. NC114 treatment inhibits the activation of PKCδ and its kinase activity, which suppresses MEK/ERK signaling. Attenuated MEK/ERK signaling then results in a reduction in FOXM1 phosphorylation and subsequent nuclear translocation of FOXM1 and β-catenin. Consequently, formation of a T-cell factor-4 (TCF4)/β-catenin transcription complex in the nucleus is inhibited and transcription of its target genes, such as cell cycle-related genes, is downregulated. The efficacy of NC114 on tumor growth was confirmed in a xenograft model. Collectively, elucidation of the mechanism by which NC114 induces growth arrest in colorectal cancer cells should provide a novel therapeutic strategy for colorectal cancer treatment.

Aurora Kinase B‐Instruct Release of AZD1152‐HQPA from Hydrogel to Enhance Cervical Cancer Suppression

AbstractAurora kinase B (AURKB) is an attractive and potential molecular target for cervical cancer therapy. To date, a variety of AURKB inhibitors are developed to suppress cervical tumors. Nevertheless, direct use of these small molecule inhibitors may cause severe side effects to patients, limiting their further clinical applications. Herein, a rationally designed hydrogelator Nap‐Phe‐Phe‐Arg‐Arg‐Lys‐Ser‐OH (S) is employed to co‐assemble AZD1152‐HQPA (AZD, an AURKB inhibitor) to develop an AURKB‐responsive hydrogel Gel S/AZD for enhanced cervical tumor suppression. Upon AURKB activation, hydrogelator S in Gel S/AZD evolves into its hydrophilic phosphate Nap‐Phe‐Phe‐Arg‐Arg‐Lys‐Ser(H2PO3)‐OH (Sp), triggering the disassembly of Gel S/AZD to release AZD in a sustained manner. Cell assays reveal that AURKB‐responsive release of AZD from Gel S/AZD potently induces the growth arrest and apoptosis of cervical cancer cells by downregulating the expression level of AURKB downstream protein phospho‐histone H3 (pH3). In vivo studies demonstrate that compared with free AZD, Gel S/AZD shows a superior tumor suppressive effect in orthotropic cervical tumor models. It is envisioned that the Gel S/AZD might be applied in clinic cervical cancer treatment in the near future.

A multi-omics integrative approach unravels novel genes and pathways associated with senescence escape after targeted therapy in NRAS mutant melanoma

Therapy Induced Senescence (TIS) leads to sustained growth arrest of cancer cells. The associated cytostasis has been shown to be reversible and cells escaping senescence further enhance the aggressiveness of cancers. Chemicals specifically targeting senescent cells, so-called senolytics, constitute a promising avenue for improved cancer treatment in combination with targeted therapies. Understanding how cancer cells evade senescence is needed to optimise the clinical benefits of this therapeutic approach. Here we characterised the response of three different NRAS mutant melanoma cell lines to a combination of CDK4/6 and MEK inhibitors over 33 days. Transcriptomic data show that all cell lines trigger a senescence programme coupled with strong induction of interferons. Kinome profiling revealed the activation of Receptor Tyrosine Kinases (RTKs) and enriched downstream signaling of neurotrophin, ErbB and insulin pathways. Characterisation of the miRNA interactome associates miR-211-5p with resistant phenotypes. Finally, iCell-based integration of bulk and single-cell RNA-seq data identifies biological processes perturbed during senescence and predicts 90 new genes involved in its escape. Overall, our data associate insulin signaling with persistence of a senescent phenotype and suggest a new role for interferon gamma in senescence escape through the induction of EMT and the activation of ERK5 signaling.

Breast cancer cell growth arrest and chemopreventive effects of Passiflora edulis Sims (Passifloraceae) ethanolic leaves extract on a rat model of mammary carcinoma.

Despite various prevention and treatment measures, the incidence and mortality due to breast cancer has been increasing globally. Passiflora edulis Sims is a plant used for the treatment of various diseases in traditional medicine, including cancers. To assess the anti-breast cancer activity of the ethanolic extract of P. edulis leaves in vitro and in vivo. In vitro, the cell growth and proliferation were determined based on the MTT and BrdU assays. The flow cytometry was used to analyze the cell death mechanism while, cell migration, cell adhesion and chemotaxis were assayed for anti-metastatic potential. In vivo, 56 female Wistar rats aged 45-50 days (∼75g) were exposed to 7,12-dimethylbenz(a)anthracene-DMBA except the normal group. Negative control group (DMBA) received solvent dilution throughout the study; standards groups (tamoxifen - 3.3mg/kg BW and letrozole - 1mg/kg BW) as well as P. edulis leaves ethanolic extract groups (50, 100 and 200mg/kg) treated for 20 weeks. Tumor incidence, tumor burden and volume, CA 15-3 serum' level, antioxidant, inflammatory status and histopathology were assessed. P. edulis extract showed a significant and concentration-dependent inhibition of MCF-7 and MDA-MB 231cells growth at 100μg/mL. It inhibited cell proliferation and clones' formation and induced apoptosis in MDA-MB 231cells. The migration of cell into the zone freed of cells and the number of invading cells after the 48 and 72h were significantly diminished while, it increased their adherence to collagen and fibronectin extracellular matrix as does Doxorubicin. In vivo, all rats in the DMBA group exhibited a significant (p < 0.001) increase in tumor volume, tumor burden and grade (adenocarcinoma of SBR III) and pro-inflammatory cytokine levels (TNF-α, INF-γ, IL-6 and IL-12). P. edulis extract at all tested doses significantly inhibited the DMBA-induced increase in tumor incidence, tumor burden and grade (SBR I) as well as pro-inflammatory cytokines. Moreover, it increased enzymatic and non-enzymatic antioxidants (SOD, catalase, and GSH) and decreased MDA levels although a greater effect was observed with Tamoxifen and Letrozole. P. edulis has medium content on polyphenols, flavonoids and tannins. P. edulis has chemo-preventive effects against DMBA-induced breast cancer in rats probably through its antioxidative, anti-inflammatory and apoptosis-inducing potentials.

Saw Palmetto may fight prostate cancer.

Saw Palmetto may fight prostate cancer.

Suppressing cancer by damaging cancer cell DNA using LED irradiation.

High-energy irradiation eliminates cancer cells by destroying their genetic components. However, there are several side effects from doing this, such as fatigue, dermatitis, and hair loss, which remain obstacles to this treatment. Here, we propose a moderate method that uses low-energy white light from a light-emitting diode (LED) to selectively inhibit cancer cell proliferation without affecting normal cells. The association between LED irradiation and cancer cell growth arrest was evaluated based on cell proliferation, viability, and apoptotic activity. Immunofluorescence, polymerase chain reaction, and western blotting were performed in vitro and in vivo to identify the metabolism related to the inhibition of HeLa cell proliferation. LED irradiation aggravated the defective p53 signaling pathway and induced cell growth arrest in cancer cells. Consequently, cancer cell apoptosis was induced by the increased DNA damage. Additionally, LED irradiation inhibited the proliferation of cancer cells by suppressing the MAPK pathway. Furthermore, the suppression of cancer growth by the regulation of p53 and MAPK was observed in cancer-bearing mice irradiated with LED. Our findings suggest that LED irradiation can suppress cancer cell activity and may contribute to preventing the proliferation of cancer cells after medical surgery without causing side effects.

UTP11 deficiency suppresses cancer development via nucleolar stress and ferroptosis

The eukaryotic ribosome is essential for cancer cell survival. Perturbation of ribosome biogenesis induces nucleolar stress or ribosomal stress, which restrains cancer growth, as rapidly proliferating cancer cells need more active ribosome biogenesis. In this study, we found that UTP11 plays an important role in the biosynthesis of 18S ribosomal RNAs (rRNA) by binding to the pre-rRNA processing factor, MPP10. UTP11 is overexpressed in human cancers and associated with poor prognoses. Interestingly, depletion of UTP11 inhibits cancer cell growth in vitro and in vivo through p53-depedednt and -independent mechanisms, whereas UTP11 overexpression promotes cancer cell growth and progression. On the one hand, the ablation of UTP11 impedes 18S rRNA biosynthesis to trigger nucleolar stress, thereby preventing MDM2-mediated p53 ubiquitination and degradation through ribosomal proteins, RPL5 and RPL11. On the other hand, UTP11 deficiency represses the expression of SLC7A11 by promoting the decay of NRF2 mRNA, resulting in reduced levels of glutathione (GSH) and enhanced ferroptosis. Altogether, our study uncovers a critical role for UTP11 in maintaining cancer cell survival and growth, as depleting UTP11 leads to p53-dependent cancer cell growth arrest and p53-independent ferroptosis.

Abstract 1421: Targeting ASPM suppresses the tumorigenicity of human hepatocellular carcinoma cells via ASPM-TPX2 axis disruption and result in increased chromosome segregation error

Abstract Aneuploidy and chromosomal instability (CIN) are common abnormalities in human cancer, might arise from a lesion in the chromosome segregation machinery. CIN has a tumour suppressive role because of excessive genomic damage and subsequent apoptosis or other forms of cell death. Therefore, induced massive chromosome instability and led to cellular death in cancer cells can be one of the most successful strategies for cancer therapy. ASPM is a critical regulator of cell-cycle progression, DNA damage and genome stability. In our previous work, we showed that ASPM was often overexpressed in human HCC and associated with tumor malignance progression and poor prognosis. However, the molecular roles of ASPM in the liver cancer cells still unclear. In this study, our results indicated that targeting ASPM caused a rising impaired chromosomal instability resulting in multinuclearity, mitosis progression prolong, increased multicentrosomes, chromosome segregation error and led to chromosome numbers variation in liver cancer cells. Finally, ASPM inhibition led to cell cycle progression arrest and apoptosis in liver cancer cells. Moreover, in vitro tumor spheroid assay and in vivo xenografts mouse model showed a therapeutic opportunity. Our results indicated the effect of ASPM silencing was led to chromosome segregation error in liver cancer cell. In mechanism analysis, the TPX2 was similar binary expression with ASPM in HCC and as downstream target. In our previous work, targeting TPX2 suppresses the tumorigenesis of hepatocellular carcinoma cells resulting in arrested mitotic phase progression and increased genomic instability. However, silenced ASPM or TPX2 both led to deregulated cyclin B2 protein expression. These results indicated ASPM-TPX2-Cyclin B2 axis was co-expression and TPX2-Cyclin B2 should be the potential downstream targets of ASPM. Moreover, in this study, ASPM was interacted with TPX2 and co-localized at mitotic spindle pore. Overexpression of EGFP-TPX2 was semi-restored the cell fitness caused by ASPM inhibition in liver cancer cells. Taken together, our results indicated that ASPM play important roles in cell proliferation, tumorigenesis and cell cycle progression in HCC cells. These results suggested a new insight into the mechanism of ASPM depletion through deregulated TPX2 and result in Cyclin B2 protein downregulation and contributed to cancer cell growth arrest, chromosome instability and cell death in hepatocellular carcinoma. Citation Format: Hung-Wei Pan, Zhong-Zhe Lin, Guan-Jin Huang. Targeting ASPM suppresses the tumorigenicity of human hepatocellular carcinoma cells via ASPM-TPX2 axis disruption and result in increased chromosome segregation error [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1421.

ROS mediated apoptosis and cell cycle arrest in human lung adenocarcinoma cell line by silver nanoparticles synthesized using Swietenia macrophylla seed extract

Cancer is considered one of the most dreaded diseases around the world. Researchers have been exploring innovative anticancer medicines to expand the number of therapy options and generate less toxic and more effective medications that can stimulate apoptosis and growth arrest in cancer cells. Biosynthesis of silver nanoparticles has piqued attention due to the use of plant secondary metabolites that does not aid only in the synthesis process but provide biological properties and an eco-friendly approach. In the present study, Silver nanoparticles were synthesized from ethanol seed extract of Swietenia macrophylla and their antiproliferative mechanism against human lung adenocarcinoma (A549) cell line was evaluated. Biosynthesized Silver nanoparticles from ethanol seed extract of S. macrophylla (SM-AgNPs) were confirmed by the change of color and an absorption peak of the UV–visible spectra at 453 nm. The SM-AgNPs were further characterized by Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy coupled with Energy dispersive spectroscopy, High-resolution transmission electron microscopy, and zeta potential. The SM-AgNPs were further investigated against A549 cells for their anticancer activity. The findings revealed that SM-AgNPs exhibited concentration-dependent cytotoxicity with an IC50 value of 7.54 ± 0.07 μg/mL in A549 cells. The production of oxidative stress by the generation of reactive oxygen species by SM-AgNPs may cause the mitochondrial membrane to become sensitized, triggering the apoptosis pathway, damaging the DNA and changing the nuclear morphology, and also halting the cell cycle in A549 cells at the S-phase during cell cycle analyses. Overall, these findings reveal that biogenic SM-AgNPs can induce ROS-mediated apoptosis in A549 cells, possessing the anticancer effect.

Psymberin, a marine-derived natural product, induces cancer cell growth arrest and protein translation inhibition.

Colorectal cancer (CRC) is the third most prevalent form of cancer in the United States and results in over 50,000 deaths per year. Treatments for metastatic CRC are limited, and therefore there is an unmet clinical need for more effective therapies. In our prior work, we coupled high-throughput chemical screens with patient-derived models of cancer to identify new potential therapeutic targets for CRC. However, this pipeline is limited by (1) the use of cell lines that do not appropriately recapitulate the tumor microenvironment, and (2) the use of patient-derived xenografts (PDXs), which are time-consuming and costly for validation of drug efficacy. To overcome these limitations, we have turned to patient-derived organoids. Organoids are increasingly being accepted as a "standard" preclinical model that recapitulates tumor microenvironment cross-talk in a rapid, cost-effective platform. In the present work, we employed a library of natural products, intermediates, and drug-like compounds for which full synthesis has been demonstrated. Using this compound library, we performed a high-throughput screen on multiple low-passage cancer cell lines to identify potential treatments. The top candidate, psymberin, was further validated, with a focus on CRC cell lines and organoids. Mechanistic and genomics analyses pinpointed protein translation inhibition as a mechanism of action of psymberin. These findings suggest the potential of psymberin as a novel therapy for the treatment of CRC.

BCL6 is regulated by the MAPK/ELK1 axis and promotes KRAS-driven lung cancer.

Mutational activation of KRAS is a common oncogenic event in lung cancer, yet effective therapies are still lacking. Here, we identify B cell lymphoma 6 (BCL6) as a lynchpin in KRAS-driven lung cancer. BCL6 expression was increased upon KRAS activation in lung tumor tissue in mice and was positively correlated with the expression of KRAS-GTP, the active form of KRAS, in various human cancer cell lines. Moreover, BCL6 was highly expressed in human KRAS-mutant lung adenocarcinomas and was associated with poor patient survival. Mechanistically, the MAPK/ERK/ELK1 signaling axis downstream of mutant KRAS directly regulated BCL6 expression. BCL6 maintained the global expression of prereplication complex components; therefore, BCL6 inhibition induced stalling of the replication fork, leading to DNA damage and growth arrest in KRAS-mutant lung cancer cells. Importantly, BCL6-specific knockout in lungs significantly reduced the tumor burden and mortality in the LSL-KrasG12D/+ lung cancer mouse model. Likewise, pharmacological inhibition of BCL6 significantly impeded the growth of KRAS-mutant lung cancer cells both in vitro and in vivo. In summary, our findings reveal a crucial role of BCL6 in promoting KRAS-addicted lung cancer and suggest BCL6 as a therapeutic target for the treatment of this intractable disease.

Pharmacological targeting of CBP/p300 drives a redox/autophagy axis leading to senescence-induced growth arrest in non-small cell lung cancer cells

p300/CBP histone acetyltransferases (HAT) are critical transcription coactivators involved in multiple cellular activities. They act at multiple levels in non-small cell lung carcinoma (NSCLC) and appear, therefore, as promising druggable targets. Herein, we investigated the biological effects of A-485, the first selective (potent) drug-like HAT catalytic inhibitor of p300/CBP, in human NSCLC cell lines. A-485 treatment specifically reduced p300/CBP-mediated histone acetylation marks and caused growth arrest of lung cancer cells via activation of the autophagic pathway. Indeed, A-485 growth-arrested cells displayed phenotypic markers of cell senescence and failed to form colonies. Notably, disruption of autophagy by genetic and pharmacological approaches triggered apoptotic cell death. Mechanistically, A-485-induced senescence occurred through the accumulation of reactive oxygen species (ROS), which in turn resulted in DNA damage and activation of the autophagic pathway. Interestingly, ROS scavengers were able to revert senescence phenotype and restore cell viability, suggesting that ROS production had a key role in upstream events leading to growth arrest commitment. Altogether, our data provide new insights into the biological effects of the A-485 and uncover the importance of the autophagic/apoptotic response to design a new combinatorial anticancer strategy.

Benzimidazole-linked pyrazolo[1,5-a]pyrimidine conjugates: synthesis and detail evaluation as potential anticancer agents.

A library of benzimidazole briged pyrazolo[1,5-a]pyrimidine (6a-q) was designed, synthesized and subjected for evaluation for cytotoxic potential. Antiproliferative activity, ranging from 3.1-51.5μM, was observed against a panel of cancer cell lines which included MCF-7 (breast cancer), A549 (lung cancer), HeLa (cervical cancer) and SiHa (cervical cancer). Among them, 6k, 6l, 6n and 6o have shown significant cytotoxicity and were investigated further to study their probable mechanism of action against MCF-7 cell line. Accumulation of cells at sub-G1 phase was observed in flow cytometric analysis. The detachment of cells from substratum and membrane blebbing seen under bright field microscopy supports the ability of these conjugates to induce apoptosis. Immunostaining and western blot analysis showed EGFR, p-EGFR, STAT3, and p-STAT3 significant downregulation. Western blot analysis demonstrated an elevated level of apoptotic proteins such as p53, p21, Bax, whereas a decrease in the antiapoptotic protein Bcl-2 and procaspase-9, confirming the ability of these conjugates to trigger cell death by apoptosis. EGFR kinase assay confirms the specific activity of conjugates. Molecular docking simulation study disclosed that these molecules fit well in ATP-binding pocket of EGFR. The analysis of docking poses and the atomic interactions of different conjugates rationalize the structural-activity relationship in this series. Benzimidazole-linked pyrazolo[1,5-a]pyrimidine conjugates were synthesized and evaluated for their anticancer potential. All the conjugates have significant anticancer potential. Further mechanistic studies revealed that these conjugates arrest cancer cell growth by EGFR/STAT3 inhibition.

Effects of Metformin as Add-On Therapy against Glioblastoma: An Old Medicine for Novel Oncology Therapeutics.

Simple SummaryGlioblastoma is the most common and malignant primary brain tumor, with a median survival of around 14 months. The aggressiveness of glioblastoma is due to intense cell proliferation, angiogenesis, invasiveness, genetic instability, resistance to therapies and high frequency of relapses. These features render glioblastoma almost incurable, considered an extreme therapeutic challenge. In the last few decades, it has been observed a reduced cancer incidence in diabetic patients treated with metformin, an oral hypoglycemic drug. The reported ability of metformin to arrest cancer cell growth in in vitro and in vivo experimental tumor models, have suggested the possibility to reconsider metformin as an anti-cancer add-on therapy, but further investigations about molecular mechanisms and optimal therapeutic regimens are needed. Here, we tested the efficacy of metformin against primary glioblastoma endothelial cells, responsible for tumor angiogenesis, invasiveness and resistance to therapy, reporting promising results and advancing a novel target of metformin, the “sphingolipid rheostat”.Background: Glioblastoma is the most aggressive primary brain malignancy in adults, with a poor prognosis of about 14 months. Recent evidence ascribed to metformin (MET), an antihyperglycemic drug, the potential to reduce cancer incidence and progression, but the molecular mechanisms underlying these effects need to be better investigated. Methods: Here, we tested the efficacy of MET on n = 10 primary glioblastoma endothelial cells (GECs), by viability and proliferation tests, as MTT and Live/Dead assays, apoptosis tests, as annexin V assay and caspase 3/7 activity, functional tests as tube-like structure formation and migration assay and by mRNA and protein expression performed by quantitative real-time PCR analysis (qRT-PCR) and Western Blot, respectively. Results: Data resulting revealed a time- and μ-dependent ability of MET to decrease cell viability and proliferation, increasing pro-apoptotic mechanisms mediated by caspases 3/7. Also, MET impacted GEC functionality with a significant decrease of angiogenesis and invasiveness potential. Mechanistically, MET was able to interfere with sphingolipid metabolism, weakening the oncopromoter signaling promoted by sphingosine-1-phosphate (S1P) and shifting the balance toward the production of the pro-apoptotic ceramide. Conclusions: These observations ascribed to MET the potential to serve as add-on therapy against glioblastoma, suggesting a repurposing of an old, totally safe and tolerable drug for novel oncology therapeutics.

Sorafenib, rapamycin, and venetoclax attenuate doxorubicin-induced senescence and promote apoptosis in HCT116 cells

Emerging evidence has shown that the therapy-induced senescent growth arrest in cancer cells is of durable nature whereby a subset of cells can reinstate proliferative capacity. Promising new drugs named senolytics selectively target senescent cells and commit them into apoptosis. Accordingly, senolytics have been proposed as adjuvant cancer treatment to cull senescent tumor cells, and thus, screening for agents that exhibit senolytic properties is highly warranted. Our study aimed to investigate three agents, sorafenib, rapamycin, and venetoclax for their senolytic potential in doxorubicin-induced senescence in HCT116 cells. HCT116 cells were treated with one of the three agents, sorafenib (5 µM), rapamycin (100 nM), or venetoclax (10 µM), in the absence or presence of doxorubicin (1 µM). Senescence was evaluated using microscopy-based and flow cytometry-based Senescence-associated-β-galactosidase staining (SA-β-gal), while apoptosis was assessed using annexin V-FITC/PI, and Muse caspase-3/-7 activity assays. We screened for potential genes through which the three drugs exerted senolytic-like action using the Human Cancer Pathway Finder PCR array. The three agents reduced doxorubicin-induced senescent cell subpopulations and significantly enhanced the apoptotic effect of doxorubicin compared with those treated only with doxorubicin. The senescence genes IGFBP5 and BMI1 and the apoptosis genes CASP7 and CASP9 emerged as candidate genes through which the three drugs exhibited senolytic-like properties. These results suggest that the attenuation of doxorubicin-induced senescence might have shifted HCT116 cells to apoptosis by exposure to the tested pharmacological agents. Our work argues for the use of senolytics to reduce senescence-mediated resistance in tumor cells and to enhance chemotherapy efficacy.