Apoptosis of non-small-cell lung cancer cell lines after paclitaxel treatment involves the BH3-only proapoptotic protein Bim

KRAS mutants confer platinum resistance by regulating ALKBH5 posttranslational modifications in lung cancer

Constitutively active mutations of KRAS are prevalent in non-small cell lung cancer (NSCLC). However, the relationship between these mutations and resistance to platinum-based chemotherapy and the underlying mechanisms remain elusive. In this study, we demonstrate that KRAS mutants confer resistance to platinum in NSCLC. Mechanistically, KRAS mutants mediate platinum resistance in NSCLC cells by activating ERK/JNK signaling, which inhibits AlkB homolog 5 (ALKBH5) N6-methyladenosine (m6A) demethylase activity by regulating posttranslational modifications (PTMs) of ALKBH5. Consequently, the KRAS mutant leads to a global increase in m6A methylation of mRNAs, particularly damage-specific DNA-binding protein 2 (DDB2) and XPC, which are essential for nucleotide excision repair. This methylation stabilized the mRNA of these 2 genes, thus enhancing NSCLC cells' capability to repair platinum-induced DNA damage and avoid apoptosis, thereby contributing to drug resistance. Furthermore, blocking KRAS-mutant-induced m6A methylation, either by overexpressing a SUMOylation-deficient mutant of ALKBH5 or by inhibiting methyltransferase-like 3 (METTL3) pharmacologically, significantly sensitizes KRAS-mutant NSCLC cells to platinum drugs in vitro and in vivo. Collectively, our study uncovers a mechanism that mediates KRAS-mutant-induced chemoresistance in NSCLC cells by activating DNA repair through the modulation of the ERK/JNK/ALKBH5 PTM-induced m6A modification in DNA damage repair-related genes.

Exploring the potential of gemcitabine-metal-organic frameworks in combating pancreatic cancer under ketogenic conditions

BACKGROUND

Inadequate treatment responses, chemotherapy resistance, significant heterogeneity, and lengthy treatment durations create an urgent need for new pancreatic cancer therapies. This study aims to investigate the effectiveness of gemcitabine-loaded nanoparticles enclosed in an organo-metallic framework under ketogenic conditions in inhibiting the growth of MIA-PaCa-2 cells.

METHODS

Gemcitabine was encapsulated in Metal-organic frameworks (MOFs) and its morphology and size distribution were examined using transmission electron microscopy (TEM) and Dynamic light scattering (DLS) with further characterization including FTIR analysis. Various drug groups were established to evaluate their influences on cell cytotoxicity, apoptosis rate, cell cycle distribution, levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), and cell migration.

RESULTS

The gemcitabine-MOF was thoroughly analyzed to determine its size, morphology, and chemical composition, confirming its successful preparation. The treatment results showed an increase in the number of apoptotic cells following gemcitabine-MOF treatment, which was found to be associated with cell cycle arrest in the sub-G1 phase. Moreover, these treatments also resulted in reduced cell migration, decreased activity of antioxidant enzymes (SOD, GPx), and increased accumulation of MDA. Additionally, when exposed to ketogenic conditions (where beta-hydroxybutyrate is present in a glucose-limited medium), there was a further increase in cell cycle arrest, accompanied by a more pronounced decrease in SOD and GPx activity, as well as decreased migration.

CONCLUSION

The use of metal-organic framework to encapsulate gemcitabine yielded notable pro-apoptotic effects in MIA-PaCa-2 cells with which ketogenic conditions had a synergistic effect that can hold promise for improving therapeutic options.

Acetylation of FOXO1 activates Bim expression involved in CVB3 induced cardiomyocyte apoptosis

Viral myocarditis (VMC) is the major reason for sudden cardiac death among both children and young adults. Of these, coxsackievirus B3 (CVB3) is the most common causative agent of myocarditis. Recently, the role of signaling pathways in the pathogenesis of VMC has been evaluated in several studies, which has provided a new perspective on identifying potential therapeutic targets for this hitherto incurable disease. In the present study, in vivo and in vitro experiments showed that CVB3 infection leads to increased Bim expression and triggers apoptosis. In addition, by knocking down Bim using RNAi, we further confirmed the biological function of Bim in apoptosis induced by CVB3 infection. We additionally found that Bim and forkhead box O1 class (FOXO1) inhibition significantly increased the viability of CVB3-infected cells while blocking viral replication and viral release. Moreover, CVB3-induced Bim expression was directly dependent on FOXO1 acetylation, which is catalyzed by the co-regulation of CBP and SirTs. Furthermore, the acetylation of FOXO1 was an important step in Bim activation and apoptosis induced by CVB3 infection. The findings of this study suggest that CVB3 infection induces apoptosis through the FOXO1 acetylation-Bim pathway, thus providing new insights for developing potential therapeutic targets for enteroviral myocarditis.

Apoptotic signaling pathways in bone metastatic lung cancer: a comprehensive analysis

This review provides a comprehensive analysis of apoptotic signaling pathways in the context of bone metastatic lung cancer, emphasizing the intricate molecular mechanisms and microenvironmental influences. Beginning with an overview of apoptosis in cancer, the paper explores the specific molecular characteristics of bone metastatic lung cancer, highlighting alterations in apoptotic pathways. Focused discussions delve into key apoptotic signaling pathways, including the intrinsic and extrinsic pathways, and the roles of critical molecular players such as Bcl-2 family proteins and caspases. Microenvironmental factors, such as the tumor microenvironment, extracellular matrix interactions, and immune cell involvement, are examined in depth. The review also addresses experimental approaches and techniques employed in studying apoptotic signaling, paving the way for a discussion on current therapeutic strategies, their limitations, and future prospects. This synthesis contributes a holistic understanding of apoptosis in bone metastatic lung cancer, offering insights for potential therapeutic advancements.

Elemene Injection Overcomes Paclitaxel Resistance in Breast Cancer through AR/RUNX1 Signal: Network Pharmacology and Experimental Validation

BACKGROUND

Paclitaxel (PTX) is a cornerstone chemotherapy for Breast Cancer (BC), yet its impact is limited by emerging resistance. Elemene Injection (EI) has shown potential in overcoming chemotherapy resistance. However, the efficacy by which EI restores PTX sensitivity in BC and the implicated molecular mechanism remain uncharted.

METHODS

Network pharmacology and bioinformatic analysis were conducted to investigate the targets and mechanisms of EI in overcoming PTX resistance. A paclitaxel-resistant MCF-7 cell line (MCF-7PR) was established. The efficacy of EI and/or PTX in inhibiting cell viability was evaluated using sulforhodamine B assay, while cell proliferation was assessed using EdU staining. Furthermore, protein and gene expression analysis was performed through Western blotting and qPCR.

RESULTS

The EI containing three active components exhibited a multifaceted impact by targeting an extensive repertoire of 122 potential molecular targets. By intersecting with 761 differentially expressed genes, we successfully identified 9 genes that displayed a direct association with resistance to PTX in BC, presenting promising potential as therapeutic targets for the EI to effectively counteract PTX resistance. Enrichment analysis indicated a significant correlation between these identified targets and critical biological processes, particularly DNA damage response and cell cycle regulation. This correlation was further substantiated through meticulous analysis of single-cell datasets. Molecular docking analysis revealed robust binding affinities between the active components of the EI and the identified molecular targets. Subsequently, in vitro experiments unequivocally demonstrated the dose- and time-dependent inhibitory effects of the EI on both PTX-resistant and sensitive BC cell lines, effectively mitigating the resistance phenotype associated with PTX administration. Furthermore, our findings have indicated EI to effectively suppress the protein expression levels of AR and RUNX1 in MCF-7 and MCF-7PR cells under PTX treatment, as well as downregulate the mRNA expression levels of stem-like properties' markers, KLF4 and OCT4, in these cell lines.

CONCLUSION

Elemene Injection (EI) application has exhibited a significant capability to mitigate PTX resistance in BC, which has been achieved through targeted suppression of the AR/RUNX1 axis, revealing a key strategy to overcome chemotherapeutic resistance.

Regulation of Protein-Induced Apoptosis and Autophagy in Human Hepatocytes Treated with Metformin and Paclitaxel In Silico and In Vitro

Metformin and paclitaxel therapy offer promising outcomes in the treatment of liver cancer. Combining paclitaxel with metformin enhances treatment effectiveness and mitigates the adverse effects associated with paclitaxel alone. This study explored the anticancer properties of metformin and paclitaxel in HepG2 liver cancer cells, MCF-7 breast cancer cells, and HCT116 colon cancer cells. The results demonstrated that the combination of these agents exhibited a lower IC50 in the tested cell lines compared to paclitaxel monotherapy. Notably, treating the HepG2 cell line with this combination led to a reduction in the G0/G1 phase and an increase in the S and G2/M phases, ultimately triggering early apoptosis. To further investigate the interaction between the cellular proteins with paclitaxel and metformin, an in silico study was conducted using proteins chosen from a protein data bank (PDB). Among the proteins studied, AMPK-α, EGFRK, and FKBP12-mTOR exhibited the highest binding free energy, with values of -11.01, -10.59, and -15.63 kcal/mol, respectively, indicating strong inhibitory or enhancing effects on these proteins. When HepG2 cells were exposed to both paclitaxel and metformin, there was an upregulation in the gene expression of AMPK-α, a key regulator of the energy balance in cancer growth, as well as apoptotic markers such as p53 and caspase-3, along with autophagic markers including beclin1 and ATG4A. This combination therapy of metformin and paclitaxel exhibited significant potential as a treatment option for HepG2 liver cancer. In summary, the combination of metformin and paclitaxel not only enhances treatment efficacy but also reduces side effects. It induces cell cycle alterations and apoptosis and modulates key cellular proteins involved in cancer growth, making it a promising therapy for HepG2 liver cancer.

Synergetic effect of high dose rate radiations (10× FFF/2400 MU/min/10 MV x-rays) and paclitaxel selectively eliminates melanoma cells

BACKGROUND

Melanoma is one of the most aggressive cancers, with 1.6% of total cancer deaths in the United States. In recent years treatment options for metastatic melanoma have been improved by the FDA approval of new therapeutic agents. However, these inhibitors-based therapies are non-specific and have severe toxicities, including hyperkeratosis, photosensitivity, hepatitis, arthralgia, and fatigue.

AIMS

The aim of this study is to determine the synthetic lethal effect (paclitaxel and radiations) on melanoma cells and reduce the total radiation doses by increasing the dose rates up to 2400 MU/min.

METHODS AND RESULTS

We previously reported a radiation treatment (10 MV x-rays, 10X-FFF, dose rate 2400MU/min, low total dose 0.5 Gy) that kills melanoma cells with 80% survival of normal HEM in vitro. In this study, we extended the radiation cycle up to four and included paclitaxel treatment to study the synthetic lethal effect on melanoma and two other normal primary cells, HDF and HEK. Cells were treated with paclitaxel prior to the radiation at a dose rate of 400 and 2400 MU/min with a total radiation dose of only 0.5 Gy. Mitochondrial respiration assay, DNA damage assay, and colony formation assays were performed to study apoptosis and cell death induction. Four days of consequent radiation treatment with paclitaxel significantly reduces the survival of melanoma cells by inducing apoptosis and mitochondrial damage. After treatment, excessive DNA damage in melanoma cells leads to an increase in the expression of pro-apoptotic genes (Caspase-3) and a decrease in the expression of DNA repair gene (PARP1) and anti-apoptotic gene (Bcl-2) to activate the apoptosis pathway. The combination of paclitaxel and radiation reduces the survival of melanoma cells colonies compared to radiation alone.

CONCLUSION

Our study indicates that radiations with paclitaxel have a potential synthetic lethal effect on melanoma cells and can be developed as a melanoma therapy without toxicities or harmful effects on normal primary skin cells.

Effect of intraperitoneal docetaxel on ovarian function in mice

Taxanes are important chemotherapeutic agents used to manage breast cancer and gynaecological malignancies. However, ovarian toxicity induced by the taxane docetaxel (DOC) is of great concern. We investigated DOC-induced toxicity in the ovaries of female CD1 strain mice. The mice were divided into control (saline), DOC-5 (5 mg/kg DOC), and DOC-10 (10 mg/kg DOC) groups and administered saline or DOC on the first day of the study and two weeks later. Two weeks after the second dose, the ovaries were removed for analysis after inducing superovulation. Ovary weight, the number of secondary follicles, and the total number of follicles were reduced after DOC administration. Additionally, the expression levels of caspase-3 and the pro-apoptotic protein Bcl-2 interacting mediator of cell death (BIM) increased. Our findings suggest that high-dose DOC induces damage to growing follicles; however, it may not affect primordial follicles.Impact statementWhat is already known on this subject? Docetaxel (DOC) is one of the most effective chemotherapeutic agents used to manage various cancers. Some in-vitro studies have examined paclitaxel-induced ovarian toxicity; however, limited research on DOC is available.What do the results of this study add? We investigated DOC-induced ovarian toxicity in female CD1 strain mice at 5 mg/kg and 10 mg/kg. We found that DOC reduced ovary weight, the number of secondary follicles, and the total number of follicles, with the higher dose having a higher effect.What are the implications of these findings for clinical practice and/or further research? We believe that our study makes a significant contribution to the knowledge about the effect of DOC on ovarian function.

Targeting the mitochondria in chronic respiratory diseases

Mitochondria are one of the basic essential components for eukaryotic life survival. It is also the source of respiratory ATP. Recently published studies have demonstrated that mitochondria may have more roles to play aside from energy production. There is an increasing body of evidence which suggest that mitochondrial activities involved in normal and pathological states contribute to significant impact to the lung airway morphology and epithelial function in respiratory diseases such as asthma, COPD, and lung cancer. This review summarizes the pathophysiological pathways involved in asthma, COPD, lung cancer and highlights potential treatment strategies that target the malfunctioning mitochondria in such ailments. Mitochondria are responsive to environmental stimuli such as infection, tobacco smoke, and inflammation, which are essential in the pathogenesis of respiratory diseases. They may affect mitochondrial shape, protein production and ultimately cause dysfunction. The impairment of mitochondrial function has downstream impact on the cytosolic components, calcium control, response towards oxidative stress, regulation of genes and proteins and metabolic activities. Several novel compounds and alternative medicines that target mitochondria in asthma and chronic lung diseases have been discussed here. Moreover, mitochondrial enzymes or proteins that may serve as excellent therapeutic targets in COPD are also covered. The role of mitochondria in respiratory diseases is gaining much attention and mitochondria-based treatment strategies and personalized medicine targeting the mitochondria may materialize in the near future. Nevertheless, more in-depth studies are urgently needed to validate the advantages and efficacy of drugs that affect mitochondria in pathological states.

The Effect of Nano Albumin Combined with Paclitaxel on Drug Resistance of Breast Cancer Through Regulating ATP Binding Cassette Subfamily B Member 1 (ABCB1)

The paclitaxel is a common-used chemotherapy drug and its combination with nano albumin reduces drug side effect. However, whether nab-paclitaxel affects drug resistance of breast cancer remains unclear. This study intends to discuss the mechanism of drug resistance induced by nab-paclitaxel. The drug resistance of MCF-7/nab-paclitaxel in MCF-7 cell and cell proliferation was detected by MTT along with analysis of ABCB1 expression, cell cycle, and apoptosis. There was stronger drug resistance of nab-paclitaxel in the MCF-7/nab-paclitaxel cell group through be adopted with different concentration of nab-paclitaxel at the 0th hour, 24th hour and 48th hour. There was remarkable abnormal expression of the ABCB1 in the MCF-7/nab-paclitaxel cell group. The si-ABCB1 could release the quantity of the MCF-7/nab-paclitaxel cell blocked at S period. And the si-ABCB1 could reduce the expression of cyclin D1 and CDK2 in the MCF-7/nab-paclitaxel cell notably. But the expression level of p21 was increased when there was high concentration of si-ABCB1. The si-ABCB1 could increase the quantity of the MCF-7/nab-paclitaxel cell at the later period of cell apoptosis notably. The rat’s tumor growth was delayed obviously at the MCF-7/nabpaclitaxel cell group treated by si-ABCB1. But the inhibiting effect of the MCF-7/nab-paclitaxel cell on tumor growth was less. There was stronger drug resistance of cell for the nano albumin combined with paclitaxel. The function of cell proliferation in breast cancer was restrained by the nano albumin combined with paclitaxel mainly through inducing the expression of ABCB1, adjusting the growth of cell cycle and the expression of P21/BCL-2 protein.

XIST: A Meaningful Long Noncoding RNA in NSCLC Process

BACKGROUND

A number of studies have proposed that lncRNA XIST plays a role in the development and chemosensitivity of NSCLC. Besides, XIST may become a potential therapeutic target for NSCLC patients. The aim of this review is to reveal the biological functions and exact mechanisms of XIST in NSCLC.

METHODS

In this review, relevant researches involving the relationship between XIST and NSCLC are collected through systematic retrieval of PubMed.

RESULTS

XIST is an oncogene in NSCLC and is abnormally upregulated in NSCLC tissues. Considerable evidence has shown that XIST plays a critical role in the proliferation, invasion, migration, apoptosis and chemosensitivity of NSCLC cells. XIST mainly functions as a ceRNA in the NSCLC process, while XIST also functions at transcriptional levels.

CONCLUSION

LncRNA XIST has the potential to become a novel biomolecular marker of NSCLC and a therapeutic target for NSCLC.

Intrinsically Connected: Therapeutically Targeting the Cathepsin Proteases and the Bcl-2 Family of Protein Substrates as Co-regulators of Apoptosis

Taken with the growing importance of cathepsin-mediated substrate proteolysis in tumor biology and progression, the focus and emphasis placed on therapeutic design and development is coming into fruition. Underpinning this approach is the invariable progression from the direction of fully characterizing cathepsin protease members and their substrate targets, towards targeting such an interaction with tangible therapeutics. The two groups of such substrates that have gained much attention over the years are the pro- and anti- apoptotic protein intermediates from the extrinsic and intrinsic signaling arms of the apoptosis pathway. As proteins that are central to determining cellular fate, some of them present themselves as very favorable candidates for therapeutic targeting. However, considering that both anti- and pro- apoptotic signaling intermediates have been reported to be downstream substrates for certain activated cathepsin proteases, therapeutic targeting approaches based on greater selectivity do need to be given greater consideration. Herein, we review the relationships shared by the cathepsin proteases and the Bcl-2 homology domain proteins, in the context of how the topical approach of adopting 'BH3-mimetics' can be explored further in modulating the relationship between the anti- and pro- apoptotic signaling intermediates from the intrinsic apoptosis pathway and their upstream cathepsin protease regulators. Based on this, we highlight important future considerations for improved therapeutic design.

Utidelone inhibits growth of colorectal cancer cells through ROS/JNK signaling pathway

Utidelone (UTD1), a novel microtubule stabilizing agent, is an epothilone B analogue which was produced by genetic engineering. UTD1 has exhibited broad antitumor activity in multiple solid tumors. However, its activity and mechanism in colorectal cancer (CRC) remain to be studied. In this study, UTD1 dramatically inhibited CRC cell proliferation (with 0.38 µg/ml, 0.77 µg/ml IC50 in RKO and HCT116, respectively) in vitro. Immunofluorescence staining showed that UTD1 induced the formation of microtubule bundling and asters in RKO cells. Flow cytometry analysis demonstrated that UTD1 induced cell cycle to arrest in G2/M phase, subsequent apoptosis. Significantly, UTD1 exhibited stronger effect on inducing apoptosis than paclitaxel and 5-FU, especially in HCT15 cells which is ABCB1 high-expression. UTD1 exposure cleaved caspase-3 and poly ADP-ribose polymerase (PARP), decreased mitochondrial membrane potential, released cytochrome c, increased the production of active oxygen and activated c-Jun N-terminal kinase (JNK), suggesting ROS/JNK pathway was involved in this process. Moreover, UTD1 inhibited tumor growth and was more effective and safer compared with paclitaxel and 5-FU in RKO xenograft in nude mice. Taken together, our findings first indicate that UDT1 inhibits tumor growth in CRC xenograft model and may be a promising agent for CRC treatment.

Clinical significance of BIM deletion polymorphism in chemoradiotherapy for non-small cell lung cancer

The standard treatment for locally advanced non‐small cell lung cancer (NSCLC) is chemoradiotherapy (CRT) followed by anti‐programmed cell death‐ligand 1 (anti‐PD‐L1) treatment. BIM deletion polymorphism induces the suppression of apoptosis resulting from epidermal growth factor (EGFR)‐tyrosine kinase inhibitors in EGFR‐mutated NSCLC patients. We aimed to examine the effects of BIM polymorphism on CRT and anti‐PD‐L1/PD‐1 treatment in NSCLC patients. In this retrospective study of 1312 patients with unresectable NSCLC treated at Higashi‐Hiroshima Medical Center and Hiroshima University Hospital between April 1994 and October 2019, we enrolled those who underwent CRT or chemotherapy using carboplatin + paclitaxel or cisplatin + vinorelbine, or anti‐PD‐L1/PD‐1 treatment. Of 1312 patients, 88, 80, and 74 underwent CRT, chemotherapy, and anti‐PD‐L1/PD‐1 treatment, respectively, and 17.0%, 15.2% and 17.6% of these patients showed BIM polymorphism. Among patients receiving CRT, the progression‐free survival was significantly shorter in those with BIM deletion than in those without. In the multivariate analyses, BIM polymorphism was an independent factor of poor anti‐tumor effects. These results were not observed in the chemotherapy and anti‐PD‐L1/PD‐1 treatment groups. In in vitro experiments, BIM expression suppression using small interfering RNA in NSCLC cell lines showed a significantly suppressed anti‐tumor effect and apoptosis after irradiation but not chemotherapy. In conclusion, we showed that BIM polymorphism was a poor‐predictive factor for anti‐tumor effects in NSCLC patients who underwent CRT, specifically radiotherapy. In the implementation of CRT in patients with BIM polymorphism, we should consider subsequent treatment, keeping in mind that CRT may be insufficient.

PRKCQ inhibition enhances chemosensitivity of triple-negative breast cancer by regulating Bim

BACKGROUND

Protein kinase C theta, (PRKCQ/PKCθ) is a serine/threonine kinase that is highly expressed in a subset of triple-negative breast cancers (TNBC) and promotes their growth, anoikis resistance, epithelial-mesenchymal transition (EMT), and invasion. Here, we show that PRKCQ regulates the sensitivity of TNBC cells to apoptosis triggered by standard-of-care chemotherapy by regulating levels of pro-apoptotic Bim.

METHODS

To determine the effects of PRKCQ expression on chemotherapy-induced apoptosis, shRNA and cDNA vectors were used to modulate the PRKCQ expression in MCF-10A breast epithelial cells or triple-negative breast cancer cells (MDA-MB231Luc, HCC1806). A novel PRKCQ small-molecule inhibitor, 17k, was used to inhibit kinase activity. Viability and apoptosis of cells treated with PRKCQ cDNA/shRNA/inhibitor +/-chemotherapy were measured. Expression levels of Bcl2 family members were assessed.

RESULTS

Enhanced expression of PRKCQ is sufficient to suppress apoptosis triggered by paclitaxel or doxorubicin treatment. Downregulation of PRKCQ also enhanced the apoptosis of chemotherapy-treated TNBC cells. Regulation of chemotherapy sensitivity by PRKCQ mechanistically occurs via regulation of levels of Bim, a pro-apoptotic Bcl2 family member; suppression of Bim prevents the enhanced apoptosis observed with combined PRKCQ downregulation and chemotherapy treatment. Regulation of Bim and chemotherapy sensitivity is significantly dependent on PRKCQ kinase activity; overexpression of a catalytically inactive PRKCQ does not suppress Bim or chemotherapy-associated apoptosis. Furthermore, PRKCQ kinase inhibitor treatment suppressed growth, increased anoikis and Bim expression, and enhanced apoptosis of chemotherapy-treated TNBC cells, phenocopying the effects of PRKCQ downregulation.

CONCLUSIONS

These studies support PRKCQ inhibition as an attractive therapeutic strategy and complement to chemotherapy to inhibit the growth and survival of TNBC cells.

A High-Throughput Image Cytometry Method for the Formation, Morphometric, and Viability Analysis of Drug-Treated Mammospheres

The nonadherent mammosphere assay has been commonly used to investigate cancer stem cell activities in breast cancers that have the ability to form tumorspheres and maintain tumor growth. The sphere formation step is critical, in that it enables the construction of the mammosphere models for downstream assays. The mammosphere assay has also been used to assess the effects of drug treatment on the tumorspheres formed from primary cancer cells or cell lines. Traditionally, the mammosphere formation has been evaluated by standard microscopy systems that required external software for additional analyses. However, this method can be time-consuming and low-throughput, thus impractical for high-throughput characterization of mammosphere models and screening for potential therapeutic cancer drugs. To overcome these challenges, we developed a plate-based high-throughput method to rapidly analyze mammospheres in whole wells using the Celigo Image Cytometer. The method is employed to characterize mammosphere formation and morphology for adherent and nonadherent propagation of four breast cancer cell lines (MCF7, MDA-MB-436, MDA-MB-231, and SKBR3). Next, the dose-dependent effects of four small molecule drugs (doxorubicin, paclitaxel, 8-quinolinol, and salinomycin) are characterized based on sphere formation and viability stained with calcein AM and propidium iodide. We observed growth and morphometric differences between adherent and nonadherent propagation of the four cell lines. Furthermore, drug treatments induced various effects on mammosphere formation, morphology, and viability. The proposed image cytometry method provides a useful tool suitable for high-throughput characterization and analysis of mammospheres, which can improve assay efficiency when investigating the formation capabilities and drug-induced cytotoxicity effects.

Microtubule-targeting agents and their impact on cancer treatment

Microtubule-targeting agents (MTAs) constitute a diverse group of chemical compounds that bind to microtubules and affect their properties and function. Disruption of microtubules induces various cellular responses often leading to cell cycle arrest or cell death, the most common effect of MTAs. MTAs have found a plethora of practical applications in weed control, as fungicides and antiparasitics, and particularly in cancer treatment. Here we summarize the current knowledge of MTAs, the mechanisms of action and their role in cancer treatment. We further outline the potential use of MTAs in anti-metastatic therapy based on inhibition of cancer cell migration and invasiveness. The two main problems associated with cancer therapy by MTAs are high systemic toxicity and development of resistance. Toxic side effects of MTAs can be, at least partly, eliminated by conjugation of the drugs with various carriers. Moreover, some of the novel MTAs overcome the resistance mediated by both multidrug resistance transporters as well as overexpression of specific β-tubulin types. In anti-metastatic therapy, MTAs should be combined with other drugs to target all modes of cancer cell invasion.

The microtubule targeting agents eribulin and paclitaxel activate similar signaling pathways and induce cell death predominantly in a caspase-independent manner

Microtubule-targeting agents (MTAs) are the most effective chemotherapeutics used in cancer therapy to date, but their clinical use is often hampered by the acquisition of resistance. Thereby, elucidation of the molecular signaling pathways activated by novel FDA-approved MTAs such as eribulin is important for future therapeutic applications. In contrast to several reports, we show here that regardless of the presence of caspase-3, clinically relevant concentrations of eribulin and the classical MTA paclitaxel predominantly induce caspase-independent cell death in MCF-7 breast carcinoma cells. On the molecular level, several key proteins involved in apoptosis such as p53, Plk1, caspase-2, and Bim as well as the two MAPKs ERK and JNK were activated by both compounds to a similar extent. However, none of them proved to be important for eribulin- and paclitaxel-induced cytotoxicity, as their siRNA-mediated knockdown or inactivation by small molecule inhibitors did not alter cell death rates. In contrast, knockdown of the anti-apoptotic Bcl-2 protein, which becomes heavily phosphorylated at Ser70 during MTA treatment, resulted surprisingly in a reduction of MTA-mediated cell death. This phenomenon can be most likely explained by our observation that the absence of Bcl-2 slowed down cell cycle progression resulting in fewer cells entering mitosis, thereby delaying the mitotic capability of these MTAs to induce cell death. Taken together, although eribulin and paclitaxel disturb the mitotic spindle differently, they exhibit no functional differences in downstream molecular cell death signaling in MCF-7 breast cancer cells.

Concomitant genetic alterations having greater impact on the clinical benefit of EGFR-TKIs in EGFR-mutant advanced NSCLC than BIM deletion polymorphism

BACKGROUND

In previous studies, the predictive role of BIM deletion polymorphism with respect to responses to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has been controversial. The potential reasons for these inconsistent findings were unknown.

METHODS

Data from CTONG0901 clinical trial and medical records of Guangdong Lung Cancer Institute (GLCI) were retrospectively pooled. A total of 194 and 141 EGFR-mutant non-small cell lung cancer (NSCLC) patients treated with first- and second-generation EGFR-TKIs were examined in the CTONG0901 and GLCI cohorts, respectively. Sixty-eight patients were treated with third-generation EGFR-TKIs in the GLCI cohort. The BIM gene status was examined by next-generation sequencing.

RESULTS

The frequency of BIM deletion polymorphism was 11.3% and 17.0% in CTONG0901 and GLCI cohorts, respectively. For first- and second-generation EGFR-TKIs in CTONG0901 cohort, objective response (ORR) was 54.5% in BIM deletion group versus 56.4% in wild-type BIM group (P = .87); disease control rate (DCR) was 90.9% versus 88.4% (P = 1.00); progression-free survival (PFS) was 10.5 versus 11.2 months (P = .59); and overall survival (OS) was 20.5 versus 20.5 months (P = .73). In GLCI cohort, ORR was 54.2% versus 60.7% (P = .55); DCR was 91.7% versus 96.6% (P = .27); PFS was 10.1 versus 11.6 months (P = .63); and OS was 58.5 versus 45.0 months (P = .93). For third-generation EGFR-TKIs, ORR was 18.2% versus 63.2% (P = .02); DCR was 81.8% versus 96.5%, (P = .12); PFS was 5.8 versus 9.0 months (P = .13); and OS was 30.0 versus 24.8 months (P = .85). Cox regression analysis showed that concomitant genetic alterations could adversely affect the response to EGFR-TKIs, but not BIM deletion.

CONCLUSIONS

The presence of BIM deletion showed no relation to an impaired response to first-, second-, and third-generation EGFR-TKIs in NSCLC patients. The factors influencing the response of EGFR-TKIs were concomitant genetic alterations, but not BIM deletion.

Topological properties and in vitro identification of essential nodes of the Paclitaxel and Vincristine interactomes in PC-3 cells

Background

Microtubule-targeting agents (MTAs) disrupt microtubule dynamics, thereby inducing apoptosis via mitochondrial pathway activation through the modulation in the expression of the Bcl-2 family.

Methods

To describe topological features of the MTAs networks associated to intrinsic apoptosis induction in p53-null prostate cancer cells, we predicted and compared the interactomes and topological properties of Paclitaxel and Vincristine, and thus, the essential nodes corresponding with the pro- and anti-apoptotic proteins and their kinetics were subjected to experimental analysis in PC-3 cell line.

Results

The essential nodes of the apoptotic pathways, TP53, and CASP3, were identified in both, Paclitaxel and Vincristine networks, but the intrinsic pathway markers BCL2, BAX, and BCL2L1 were identified as hub nodes only in the Paclitaxel network. An in vitro analysis demonstrated an increase in BimEL and the cleaved-caspase-3 proteins in PC-3 cells exposed to both treatments. Immunoprecipitation analysis showed that treatments induced the releasing of Bax from the anti-apoptotic complex with Bcl-2 protein and the role of BimEL as a de-repressor from sequestering complexes, in addition, new protein complexes were identified between BimEL or Bcl-2 and cleaved-caspase-3, contributing data to the Vincristine network for p53-null cells in response to MTAs.

Conclusion

The differences in sensitivities, protein profiles, and protein complex kinetics observed between the drugs confirmed that the selectivity and stimulation of the apoptotic system vary depending on the cell's genotype, the drug used and its exposure period.

Trastuzumab in combination with paclitaxel enhances antitumor activity by promoting apoptosis in human epidermal growth factor receptor 2-positive trastuzumab-resistant gastric cancer xenograft models

Trastuzumab, a humanized anti-human epidermal growth factor receptor 2 antibody drug, is the first-line therapy for human epidermal growth factor receptor 2-positive breast and gastric cancer. For breast cancer, the benefit of continuous treatment with trastuzumab after it becomes refractory to first-line therapy has been demonstrated. However, it is unclear whether trastuzumab can show similar efficacy as a second-line treatment for gastric cancer. Here, we report that trastuzumab in combination with paclitaxel exhibits increased antitumor efficacy even for trastuzumab-resistant xenografted tumors. We derived the trastuzumab-resistant models from previously established human epidermal growth factor receptor 2-positive gastric cancer patient-derived cells. Human epidermal growth factor receptor 2 expression, PIK3CA mutation, and phosphatase and tensin homolog expression in these resistant models was equivalent to those in the trastuzumab-sensitive parental model, whereas cyclin-dependent kinase inhibitors, such as p16, p15, and p21, were downregulated. Trastuzumab in combination with paclitaxel enhanced antitumor activity in both the sensitive and resistant models. In the trastuzumab-sensitive model, the combination of trastuzumab and paclitaxel resulted in suppression of the AKT-p27-retinoblastoma protein pathway and induction of apoptosis. Although this combination did not suppress retinoblastoma protein phosphorylation in the trastuzumab-resistant model, it did markedly decrease epidermal growth factor receptor and human epidermal growth factor receptor 2 phosphorylation and further enhance paclitaxel-mediated apoptosis. These results suggested that trastuzumab in combination with paclitaxel can still exert more potent antitumor efficacy than each agent alone in trastuzumab-resistant models, providing evidence that trastuzumab remains beneficial in the treatment of trastuzumab-resistant tumors.

Cellular demolition: Proteins as molecular players of programmed cell death

Apoptosis, a well-characterized and regulated cell death programme in eukaryotes plays a fundamental role in developing or later-life periods to dispose of unwanted cells to maintain typical tissue architecture, homeostasis in a spatiotemporal manner. This silent cellular death occurs without affecting any neighboring cells/tissue and avoids triggering of immunological response. Furthermore, diminished forms of apoptosis result in cancer and autoimmune diseases, whereas unregulated apoptosis may also lead to the development of a myriad of neurodegenerative diseases. Unraveling the mechanistic events in depth will provide new insights into understanding physiological control of apoptosis, pathological consequences of abnormal apoptosis and development of novel therapeutics for diseases. Here we provide a brief overview of molecular players of programmed cell death with discussion on the role of caspases, modifications, ubiquitylation in apoptosis, removal of the apoptotic body and its relevance to diseases.

Penfluridol overcomes paclitaxel resistance in metastatic breast cancer

Paclitaxel is a first line chemotherapeutic agent for the patients with metastatic breast cancer. But inherited or acquired resistance to paclitaxel leads to poor response rates in a majority of these patients. To identify mechanisms of paclitaxel resistance, we developed paclitaxel resistant breast cancer cell lines, MCF-7 and 4T1 by continuous exposure to paclitaxel for several months. Western blot analysis showed increased expression of HER2 and β-catenin pathway in resistant cell lines as compared to parent cells. Hence, we hypothesized that HER2/β-catenin mediates paclitaxel resistance in breast cancer and suppression of HER2/β-catenin signaling could overcome paclitaxel resistance. Our data showed that penfluridol (PFL) treatment significantly reduced the survival of paclitaxel-resistant cells. Western blot analysis revealed that PFL treatment suppressed HER2, as well as, β-catenin pathway. In vivo data confirmed that PFL significantly potentiated tumor growth suppressive effects of paclitaxel in an orthotropic breast cancer model. In addition, tumors from paclitaxel and PFL-treated mice showed reduced HER2 and β-catenin expression, along with increased apoptosis. Taken together our results demonstrate a novel role of HER2/β-catenin in paclitaxel resistance and open up new avenues for application of PFL as a therapeutic option for overcoming paclitaxel resistance.

Resistance to anti-microtubule drug-induced cell death is determined by regulation of BimEL expression

Anti-microtubule agents are frequently used as anticancer therapeutics. Cell death induced by these agents is considered to be due to sustained mitotic arrest caused by the activation of spindle assembly checkpoint (SAC). However, some cell types are resistant to mitotic cell death. Cells' ability to escape mitotic arrest (mitotic slippage) is thought to be a major mechanism contributing to this resistance. Here, we show that resistance to cell death induced by anti-mitotic agents is not linked to cells' capacity to undergo mitotic slippage as generally believed but is dependent on the state of BimEL regulation during mitosis. While transcriptional repression of BimEL in the mitotic death-resistant cells involves polycomb repressive complex 2 (PRC2)-mediated histone trimethylation, the BimEL protein is destabilized by cullin 1/4A-βTrCP-dependent degradation involving activation of cullin 1/4A by neddylation. These results imply that pharmacological augmentation of BimEL activity in anti-microtubule drug-resistant tumors may have important therapeutic implications.

Microtubule network as a potential candidate for targeting by gold nanoparticle-assisted photothermal therapy

Photothermal therapy is achieving ever-increasing attention as a promising method for killing cancer cells. Although, gold nanoparticles are regarded as one of the most effective photothermal therapy agents, the mechanisms underlying their action have to be addressed. Moreover, studies have showed that gold nanoparticles induce apoptosis in treated cultures. Hence, in this study, we investigated the interaction of folic acid functionalized gold nanoparticles and gold-shelled Fe₃O₄ nanoparticles with microtubule and microtubule associated protein tau in order to introduce intracellular targets of these nanoparticles and provide a holistic view about the mechanism of action of gold nanoparticles used in photothermal therapy. Various spectroscopic methods were used to find gold nanoparticles interaction with Tubulin and Tau. Our results indicated that these gold nanoparticles interact with both Tau and Tubulin and their affinity increases as temperature rises. Also, the results illustrated that quenching mechanism for gold nanoparticles interaction with Tubulin and Tau was static. The hydrophobic interaction was determined as driving force for gold nanoparticles binding to Tubulin and Tau. Moreover, it was showed that both type of gold nanoparticles stabilize microtubule polymers. These results suggest Tau and Tubulin as intracellular target of gold nanoparticles and propose that microtubule network is at the heart of apoptosis mechanisms initiated by photothermal therapy.

A systematic review and meta-analysis of individual patient data on the impact of the BIM deletion polymorphism on treatment outcomes in epidermal growth factor receptor mutant lung cancer

BACKGROUND

A germline deletion in the BIM (BCL2L11) gene has been shown to impair the apoptotic response to tyrosine kinase inhibitors (TKIs) in vitro but its association with poor outcomes in TKI-treated non-small cell lung cancer (NSCLC) patients remains unclear. We conducted a systematic review and meta-analysis on both aggregate and individual patient data to address this issue.

RESULTS

In an aggregate data meta-analysis (n = 1429), the BIM deletion was associated with inferior PFS (HR = 1.51, 95%CI = 1.06-2.13, P = 0.02). Using individual patient data (n = 1200), we found a significant interaction between the deletion and ethnicity. Amongst non-Koreans, the deletion was an independent predictor of shorter PFS (Chinese: HR = 1.607, 95%CI = 1.251-2.065, P = 0.0002; Japanese: HR = 2.636, 95%CI = 1.603-4.335, P = 0.0001), and OS (HR = 1.457, 95% CI = 1.063-1.997, P = 0.019). In Kaplan-Meier analyses, the BIM deletion was associated with shorter survival in non-Koreans (PFS: 8.0 months v 11.1 months, P < 0.0005; OS: 25.7 v 30.0 months, P = 0.042). In Koreans, the BIM deletion was not predictive of PFS or OS.

MATERIALS AND METHODS

10 published and 3 unpublished studies that reported survival outcomes in NSCLC patients stratified according to BIM deletion were identified from PubMed and Embase. Summary risk estimates were calculated from aggregate patient data using a random-effects model. For individual patient data, Kaplan-Meier analyses were supported by multivariate Cox regression to estimate hazard ratios (HRs) for PFS and OS.

CONCLUSIONS

In selected populations, the BIM deletion is a significant predictor of shorter PFS and OS on EGFR-TKIs. Further studies to determine its effect on response to other BIM-dependent therapeutic agents are needed, so that alternative treatment strategies may be devised.

MiR-144-3p promotes the tumor growth and metastasis of papillary thyroid carcinoma by targeting paired box gene 8

Background

Paired box gene 8 (PAX8) is expressed in and indispensable to thyroid development. MiR-144-3p is found dys-regulated in cancers, and it can block the expression of target gens. This study sought to understand the effect of MiR-144-3p in papillary thyroid carcinoma (PTC) as well as the associated mechanisms.

Materials and methods

Real-time PCR, immunohistochemical and Western blot assays were performed to examine the expression of target miRNA and/or genes. CCK-8 and flow cytometry analysis was used to respectively test cell growth, cell cycle progression and apoptosis. Luciferase reporter assay was performed to find out whether miR-144-3p could bind to the 3′ untranslated region of PAX8 or not.

Results

We found that PAX8 decreased in PTC, while miR-144-3p increased in PTC. Over-expression of miR-144-3p promoted the cell viability and cell cycle progression. The expressions of cell-cycle-related genes, cyclin D1, cyclin-dependent kinase 2 and CDC25A were modulated by miR-144-3p. Meanwhile, the presence or absence of miR-144-3p both affected epithelial-mesenchymal transition of PTC by regulating the expression of E-cadherin, N-cadherin and vimentin. Moreover, PAX8 may be a potential direct target of miR-144-3p. Mechanically, the activation of extracellular signal–regulated kinases 1/2, Akt and c-Jun N-terminal kinases may be associated with the tumor-promoting effect of miR-144-3p. In addition, the blockage of miR-144-3p forced the anti-tumor effect delivered by X-ray exposure or paclitaxel.

Conclusion

MiR-144-3p promoted the growth of tumor and the metastasis of PTC by targeting PAX 8. The study provided promising prognosis markers and valuable treatment strategy for PTC.

Gene and MicroRNA Perturbations of Cellular Response to Pemetrexed Implicate Biological Networks and Enable Imputation of Response in Lung Adenocarcinoma

Pemetrexed is indicated for non-small cell lung carcinoma and mesothelioma, but often has limited efficacy due to drug resistance. To probe the molecular mechanisms underlying chemotherapeutic response, we performed mRNA and microRNA (miRNA) expression profiling of pemetrexed treated and untreated lymphoblastoid cell lines (LCLs) and applied a hierarchical Bayesian method. We identified genetic variation associated with gene expression in human lung tissue for the most significant differentially expressed genes (Benjamini-Hochberg [BH] adjusted p < 0.05) using the Genotype-Tissue Expression data and found evidence for their clinical relevance using integrated molecular profiling and lung adenocarcinoma survival data from The Cancer Genome Atlas project. We identified 39 miRNAs with significant differential expression (BH adjusted p < 0.05) in LCLs. We developed a gene expression based imputation model of drug sensitivity, quantified its prediction performance, and found a significant correlation of the imputed phenotype generated from expression data with survival time in lung adenocarcinoma patients. Differentially expressed genes (MTHFD2 and SUFU) that are putative targets of differentially expressed miRNAs also showed differential perturbation in A549 fusion lung tumor cells with further replication in A549 cells. Our study suggests pemetrexed may be used in combination with agents that target miRNAs to increase its cytotoxicity.

BCL-2 family proteins: changing partners in the dance towards death

The BCL-2 family of proteins controls cell death primarily by direct binding interactions that regulate mitochondrial outer membrane permeabilization (MOMP) leading to the irreversible release of intermembrane space proteins, subsequent caspase activation and apoptosis. The affinities and relative abundance of the BCL-2 family proteins dictate the predominate interactions between anti-apoptotic and pro-apoptotic BCL-2 family proteins that regulate MOMP. We highlight the core mechanisms of BCL-2 family regulation of MOMP with an emphasis on how the interactions between the BCL-2 family proteins govern cell fate. We address the critical importance of both the concentration and affinities of BCL-2 family proteins and show how differences in either can greatly change the outcome. Further, we explain the importance of using full-length BCL-2 family proteins (versus truncated versions or peptides) to parse out the core mechanisms of MOMP regulation by the BCL-2 family. Finally, we discuss how post-translational modifications and differing intracellular localizations alter the mechanisms of apoptosis regulation by BCL-2 family proteins. Successful therapeutic intervention of MOMP regulation in human disease requires an understanding of the factors that mediate the major binding interactions between BCL-2 family proteins in cells.

Chemodrug delivery using integrin-targeted PLGA-Chitosan nanoparticle for lung cancer therapy

In this study, we report the efficacy of RGD (arginine-glycine-aspartic acid) peptide-modified polylactic acid-co-glycolic acid (PLGA)-Chitosan nanoparticle (CSNP) for integrin α_vβ₃ receptor targeted paclitaxel (PTX) delivery in lung cancer cells and its impact on normal cells. RGD peptide-modified chitosan was synthesized and then coated onto PTX-PLGA nanoparticles prepared by emulsion-solvent evaporation. PTX-PLGA-CSNP-RGD displayed favorable physicochemical properties for a targeted drug delivery system. The PTX-PLGA-CSNP-RGD system showed increased uptake via integrin receptor mediated endocytosis, triggered enhanced apoptosis, and induced G2/M cell cycle arrest and more overall cytotoxicity than its non-targeted counterpart in cancer cells. PTX-PLGA-CSNP-RGD showed less toxicity in lung fibroblasts than in cancer cells, may be attributed to low drug sensitivity, nevertheless the study invited close attention to their transient overexpression of integrin α_vβ₃ and cautioned against corresponding uptake of toxic drugs, if any at all. Whereas, normal human bronchial epithelial (NHBE) cells with poor integrin α_vβ₃ expression showed negligible toxicity to PTX-PLGA-CSNP-RGD, at equivalent drug concentrations used in cancer cells. Further, the nanoparticle demonstrated its capacity in targeted delivery of Cisplatin (CDDP), a drug having physicochemical properties different to PTX. Taken together, our study demonstrates that PLGA-CSNP-RGD is a promising nanoplatform for integrin targeted chemotherapeutic delivery to lung cancer.

Inhibition of Bcl-xL sensitizes cells to mitotic blockers, but not mitotic drivers

Cell fate in response to an aberrant mitosis is governed by two competing networks: the spindle assembly checkpoint (SAC) and the intrinsic apoptosis pathway. The mechanistic interplay between these two networks is obscured by functional redundancy and the ability of cells to die either in mitosis or in the subsequent interphase. By coupling time-lapse microscopy with selective pharmacological agents, we systematically probe pro-survival Bcl-xL in response to various mitotic perturbations. Concentration matrices show that BH3-mimetic-mediated inhibition of Bcl-xL synergises with perturbations that induce an SAC-mediated mitotic block, including drugs that dampen microtubule dynamics, and inhibitors targeting kinesins and kinases required for spindle assembly. By contrast, Bcl-xL inhibition does not synergize with drugs which drive cells through an aberrant mitosis by overriding the SAC. This differential effect, which is explained by compensatory Mcl-1 function, provides opportunities for patient stratification and combination treatments in the context of cancer chemotherapy.

BAK is a predictive and prognostic biomarker for the therapeutic effect of docetaxel treatment in patients with advanced gastric cancer

BACKGROUND

Preoperative chemotherapy is a promising strategy for downstaging advanced gastric cancer before radical resection, although severe adverse events can occur and clinical outcomes are often unsatisfactory. To identify predictive biomarkers of drug sensitivity, we used a well-designed functional apoptosis assay and assessed the correlations between chemosensitivity and clinical outcomes.

METHODS

Drug sensitivity to docetaxel, cisplatin, and 5-fluorouracil was examined in 11 gastric cancer cell lines. BCL2-homology domain 3 (BH3) profiling was performed and assessed for correlations with drug sensitivity. Immunohistochemical staining of clinical gastric cancer specimens was performed before preoperative chemotherapy, and correlations with histopathological responses and clinical outcomes were assessed.

RESULTS

BIM (BCL2L11)-BH3 profiling results correlated with docetaxel sensitivity and BAK protein expression, whose knockdown caused docetaxel resistance. The BAK expression indexes of 69 gastric cancer specimens before preoperative chemotherapy (including docetaxel treatment) were determined by multiplying numerical values describing the degrees of BAK positivity and staining intensity observed. Patients whose specimens showed good chemotherapeutic histopathological responses had higher BAK indexes than those with poor responses. Patients with BAK index values ≥3 showed improved progression-free survival (HR, 2.664; 95 % CI, 1.352-5.248; P = 0.005) and overall survival (HR, 3.390; 95 % CI, 1.549-7.422; P = 0.002).

CONCLUSIONS

BH3 profiling clearly showed that BIM expression, which depends on BAK expression, correlated with docetaxel sensitivity. BAK expression in gastric cancer is thus predictive of chemotherapeutic responses to docetaxel and clinical prognosis in patients treated with preoperative chemotherapy.

Impact of the Bim Deletion Polymorphism on Survival Among Patients With Completely Resected Non-Small-Cell Lung Carcinoma

Purpose

A deletion polymorphism of the Bim gene has been reported to be a prognostic factor for patients with non–small-cell lung cancer (NSCLC) treated with epidermal growth factor receptor-tyrosine kinase inhibitors in the Asian population. We investigated the impact of the Bim deletion polymorphism on survival among patients with completely resected NSCLC.

Patients and Methods

The Bim polymorphism was detected by polymerase chain reaction analysis. We measured overall survival (OS) and recurrence-free survival rates in 411 patients and postrecurrence survival (PRS) in 94 patients who experienced recurrence and received additional anticancer therapy.

Results

The Bim deletion polymorphism was detected in 61 patients (14.8%). OS rates were significantly lower for patients with the Bim deletion polymorphism than for those with the wild-type sequence. On multivariable analysis, the Bim deletion polymorphism was identified as an independent prognostic factor for OS (hazard ratio, 1.98; 95% CI, 1.17 to 3.36; P = .011). Among the 94 patients who experienced recurrence and were treated with anticancer therapy, patients with the Bim deletion polymorphism showed significantly poorer PRS than those with the wild-type sequence (median, 9.8 months v 26.9 months, respectively; P < .001). Multivariable analysis revealed that the Bim deletion polymorphism was an independent predictor of PRS (hazard ratio, 3.36; 95% CI, 1.75 to 6.47; P < .001). This trend remained apparent in subgroup analyses stratified by EGFR status, histology, and therapeutic modality.

Conclusion

The Bim deletion polymorphism is a novel indicator of shortened PRS among patients with recurrent NSCLC treated with anticancer therapy in the Asian population.

Inhibition of FOXO1 by small interfering RNA enhances proliferation and inhibits apoptosis of papillary thyroid carcinoma cells via Akt/FOXO1/Bim pathway

Forkhead box protein O1 (FOXO1) is a multifunctional transcription factor of the forkhead family. It may function as a tumor suppressor through its ability to regulate cellular events, including cell proliferation, apoptosis, and cell cycle control. As reported, FOXO1 is downregulated in papillary thyroid carcinoma (PTC). However, the function of FOXO1 in human PTC remains unclear. In this study, we investigated the function and underlying regulatory mechanisms of FOXO1 in PTC cells. PTC cell lines K1 and TPC1 were transiently transfected with FOXO1 small interfering RNA (siRNA) and negative control RNA. Successful transfection was confirmed by RT-qPCR and Western blot analysis. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell proliferation assays, colony formation assays, apoptosis, and cell cycle assays were used to explore the potential function of FOXO1 in the PTC cell lines. We found that downregulation of FOXO1 promoted cellular proliferation, enhanced clonogenesis, and inhibited cellular apoptosis. However, the cell cycle was not markedly affected by FOXO1 siRNA. Furthermore, Bim, a downstream target of the Akt/FOXO1 signaling pathway, was downregulated at both mRNA and protein levels in cells transfected with FOXO1 siRNA. Collectively, these results indicate that FOXO1 may play an important role in inhibiting PTC development by regulating cellular proliferation, growth, and apoptosis. FOXO1 expression is a potentially useful biomarker for human PTC. Moreover, tumorigenesis of PTC may be associated with repression of the Akt/FOXO1/Bim signaling pathway.

Targeting the Mitotic Catastrophe Signaling Pathway in Cancer

Mitotic catastrophe, as defined in 2012 by the International Nomenclature Committee on Cell Death, is a bona fide intrinsic oncosuppressive mechanism that senses mitotic failure and responds by driving a cell to an irreversible antiproliferative fate of death or senescence. Thus, failed mitotic catastrophe can promote the unrestrained growth of defective cells, thereby representing a major gateway to tumour development. Furthermore, the activation of mitotic catastrophe offers significant therapeutic advantage which has been exploited in the action of conventional and targeted anticancer agents. Yet, despite its importance in tumour prevention and treatment, the molecular mechanism of mitotic catastrophe is not well understood. A better understanding of the signals that determine cell fate following failed or defective mitosis will reveal new opportunities to selectively target and enhance the programme for therapeutic benefit and reveal biomarkers to predict patient response. This review is focused on the molecular mechanism of mitotic catastrophe induction and signalling and highlights current strategies to exploit the process in cancer therapy.

High Bak Expression Is Associated with a Favorable Prognosis in Breast Cancer and Sensitizes Breast Cancer Cells to Paclitaxel

Breast cancer has become the leading cause of cancer-related death among women. A large number of patients become resistant to drug chemotherapy. Paclitaxel (Taxol) is an effective chemotherapeutic agent used to treat cancer patients. Taxol has been widely used in human malignancies including breast cancer because it can stabilize microtubules resulting in cell death by causing an arrest during the G2/M phase of the cell cycle. Pro-apoptotic Bcl-2 antagonist killer 1 (Bak) plays an important role in Taxol-induced apoptosis in breast cancer. In our present study, we investigated the expression of the Bak protein and clinicopathological correlations in a large sample of breast cancer tissues by immunohistochemistry. We found that the percentage of high scores of Bak expression in breast cancer was significantly lower than that of the non-cancerous breast control tissue. In addition, lower Bak expression was positively associated with the clinical TNM stage of breast cancer with a significant decrease in overall survival compared with those with higher Bak expression especially in the Luminal and HER2 subtypes. Importantly, higher Bak expression predicted a favorable clinical outcome in the cases treated with Taxol indicated by a higher overall survival than that of patients with lower Bak expression especially in Luminal and HER2 subtypes. Furthermore, these results were confirmed in vitro since overexpression of Bak sensitized breast cancer cells to Taxol by inhibiting proliferation and promoting apoptosis; in contrast, downregulation of Bak through siRNA transfection inhibited Taxol induced-apoptosis. Therefore, our results demonstrate that Bak acts as a sensitive biomarker and favorable prognostic factor for Taxol treatment in breast cancer. The restoration of Bak expression would be therapeutically beneficial for Taxol resistant breast cancer patients.

Regulation of Bim in Health and Disease

The BH3-only Bim protein is a major determinant for initiating the intrinsic apoptotic pathway under both physiological and pathophysiological conditions. Tight regulation of its expression and activity at the transcriptional, translational and post-translational levels together with the induction of alternatively spliced isoforms with different pro-apoptotic potential, ensure timely activation of Bim. Under physiological conditions, Bim is essential for shaping immune responses where its absence promotes autoimmunity, while too early Bim induction eliminates cytotoxic T cells prematurely, resulting in chronic inflammation and tumor progression. Enhanced Bim induction in neurons causes neurodegenerative disorders including Alzheimer's, Parkinson's and Huntington's diseases. Moreover, type I diabetes is promoted by genetically predisposed elevation of Bim in β-cells. On the contrary, cancer cells have developed mechanisms that suppress Bim expression necessary for tumor progression and metastasis. This review focuses on the intricate network regulating Bim activity and its involvement in physiological and pathophysiological processes.

Bcl-2-like protein 11 deletion polymorphism predicts survival in advanced non-small-cell lung cancer

INTRODUCTION

Germline Bcl-2-like protein 11 (BIM) deletion polymorphism in Asian is a poor predictive factor for treatment outcomes to tyrosine kinase inhibitors (TKIs) in malignancies. We explored the impact of BIM deletion polymorphism on treatment outcome of advanced non-small-cell lung cancer (NSCLC).

METHODS

We prospectively collected tissue samples, blood, and clinical data from two cohorts of advanced NSCLC patients. BIM deletion polymorphism was correlated with overall survival (OS) and progression-free survival (PFS) to epidermal growth factor receptor (EGFR) TKIs and chemotherapy treatment.

RESULTS

BIM deletion polymorphism was detected in blood of 16.2% (33 of 204) patients. The PFS to first-line EGFR-TKIs in 153 patients were 8.6 and 4.6 months for patients with wild-type BIM and BIM deletion polymorphism, respectively (p = 0.004). Among 120 patients who received chemotherapies, the PFS to chemotherapies were 5.6 and 3.5 months for patients with wild-type BIM and BIM deletion polymorphism, respectively (p = 0.050). The OS of all 204 patients was 24.8 and 16.8 months for patients with wild-type BIM and BIM deletion polymorphism, respectively (p = 0.005). Multivariate analyses suggested that BIM deletion polymorphism was an independent predictor for shorter PFS to EGFR-TKIs (hazard ratio [HR] 2.15, p = 0.002), PFS to chemotherapy (HR 2.40, p = 0.016), and OS (HR 1.65, p = 0.039).

CONCLUSIONS

BIM deletion polymorphism predicts shorter PFS to EGFR-TKIs and OS in advanced NSCLC.

Trametinib with or without vemurafenib in BRAF mutated non-small cell lung cancer

V-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF) mutated lung cancer is relatively aggressive and is resistant to currently available therapies. In a recent phase II study for patients with BRAF-V600E non-small cell lung cancer (NSCLC), BRAF V600E inhibitor demonstrated evidence of activity, but 30% of this selected group progressed while on treatment, suggesting a need for developing alternative strategies. We tested two different options to enhance the efficacy of vemurafenib (BRAF V600E inhibitor) in BRAF mutated NSCLC. The first option was the addition of erlotinib to vemurafenib to see whether the combination provided synergy. The second was to induce MEK inhibition (downstream of RAF) with trametinib (MEK inhibitor). We found that the combination of vemurafenib and erlotinib was not synergistic to the inhibition of p-ERK signaling in BRAF-V600E cells. Vemurafenib caused significant apoptosis, G1 arrest and upregulation of BIM in BRAF-V600 cells. Trametinib was effective as a single agent in BRAF mutated cells, either V600E or non-V600E. Finally, the combination of vemurafenib and trametinib caused a small but significant increase in apoptosis as well as a significant upregulation of BIM when compared to either single agent. Thus, hinting at the possibility of utilizing a combinational approach for the management of this group of patients. Importantly, trametinib alone caused upregulation of p-AKT in BRAF non-V600 mutated cells, while this effect was nullified with the combination. This finding suggests that, the combination of a MEK inhibitor with a BRAF inhibitor will be more efficacious in the clinical setting for patients with BRAF mutated NSCLC.

Organelle-specific initiation of cell death

In a majority of pathophysiological settings, cell death is not accidental - it is controlled by a complex molecular apparatus. Such a system operates like a computer: it receives several inputs that inform on the current state of the cell and the extracellular microenvironment, integrates them and generates an output. Thus, depending on a network of signals generated at specific subcellular sites, cells can respond to stress by attemptinwg to recover homeostasis or by activating molecular cascades that lead to cell death by apoptosis or necrosis. Here, we discuss the mechanisms whereby cellular compartments - including the nucleus, mitochondria, plasma membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, cytoskeleton and cytosol - sense homeostatic perturbations and translate them into a cell-death-initiating signal.

Analysis of BIM (BCL-2 like 11 gene) deletion polymorphism in Chinese non-small cell lung cancer patients

BACKGROUND

Drug resistance significantly weakens the efficacy of cancer treatment, and the BIM (also known as the BCL2L11 gene) deletion polymorphism has been identified as a potential biomarker for drug resistance. In this retrospective study, we included a total of 290 patients with advanced non-small cell lung cancer (NSCLC) who received treatment with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) and chemotherapy.

METHODS

The BIM deletion polymorphism of each patient was detected by polymerase chain reaction. EGFR mutations were detected by denaturing high-performance liquid chromatography methods and the amplification refractory mutation system.

RESULTS

The BIM deletion polymorphism was detected in 45/290 (15.5%) Chinese NSCLC patients. No associations were observed between the BIM deletion and clinic-pathologic characteristics of patients. The BIM deletion polymorphism was predictive of shorter progression-free survival in Chinese patients with EGFR-mutant adenocarcinoma and who were treated with EGFR-TKIs (7.30 vs. 9.53 months, P = 0.034). Additionally, we found that the BIM deletion polymorphism was an effective predictor of short progression-free survival in individuals with EGFR-mutant NSCLC and treated with chemotherapy containing pemetrexed (3.32 vs. 5.30, P = 0.012) or second-/beyond-line chemotherapy containing taxanes (1.53 vs. 2.61 months, P = 0.025). The BIM deletion was not correlated with overall survival.

CONCLUSION

The BIM deletion polymorphism occurs in 15.5% of Chinese NSCLC patients, and is a biomarker for resistance to TKIs and chemotherapy. However, BIM deletion was not a decisive factor in overall survival.

Overexpression of heat shock protein 27 (HSP27) increases gemcitabine sensitivity in pancreatic cancer cells through S-phase arrest and apoptosis

We previously established a role for HSP27 as a predictive marker for therapeutic response towards gemcitabine in pancreatic cancer. Here, we investigate the underlying mechanisms of HSP27-mediated gemcitabine sensitivity. Utilizing a pancreatic cancer cell model with stable HSP27 overexpression, cell cycle arrest and apoptosis induction were analysed by flow cytometry, nuclear staining, immunoblotting and mitochondrial staining. Drug sensitivity studies were performed by proliferation assays. Hyperthermia was simulated using mild heat shock at 41.8°C. Upon gemcitabine treatment, HSP27-overexpressing cells displayed an early S-phase arrest subsequently followed by a strongly increased sub-G1 fraction. Apoptosis was characterized by PARP-, CASPASE 3-, CASPASE 8-, CASPASE 9- and BIM- activation along with a mitochondrial membrane potential loss. It was reversible through chemical caspase inhibition. Importantly, gemcitabine sensitivity and PARP cleavage were also elicited by heat shock-induced HSP27 overexpression, although to a smaller extent, in a panel of pancreatic cancer cell lines. Finally, HSP27-overexpressing pancreatic cancer cells displayed an increased sensitivity also towards death receptor-targeting agents, suggesting another pro-apoptotic role of HSP27 along the extrinsic apoptosis pathway. Taken together, in contrast to the well-established anti-apoptotic properties of HSP27 in cancer, our study reveals novel pro-apoptotic functions of HSP27—mediated through both the intrinsic and the extrinsic apoptotic pathways—at least in pancreatic cancer cells. HSP27 could represent a predictive marker of therapeutic response towards specific drug classes in pancreatic cancer and provides a novel molecular rationale for current clinical trials applying the combination of gemcitabine with regional hyperthermia in pancreatic cancer patients.

Genome-wide siRNA screen reveals coupling between mitotic apoptosis and adaptation

The antimitotic anti-cancer drugs, including taxol, perturb spindle dynamics, and induce prolonged, spindle checkpoint-dependent mitotic arrest in cancer cells. These cells then either undergo apoptosis triggered by the intrinsic mitochondrial pathway or exit mitosis without proper cell division in an adaptation pathway. Using a genome-wide small interfering RNA (siRNA) screen in taxol-treated HeLa cells, we systematically identify components of the mitotic apoptosis and adaptation pathways. We show that the Mad2 inhibitor p31(comet) actively promotes mitotic adaptation through cyclin B1 degradation and has a minor separate function in suppressing apoptosis. Conversely, the pro-apoptotic Bcl2 family member, Noxa, is a critical initiator of mitotic cell death. Unexpectedly, the upstream components of the mitochondrial apoptosis pathway and the mitochondrial fission protein Drp1 contribute to mitotic adaption. Our results reveal crosstalk between the apoptosis and adaptation pathways during mitotic arrest.

API5 confers tumoral immune escape through FGF2-dependent cell survival pathway

Identifying immune escape mechanisms used by tumors may define strategies to sensitize them to immunotherapies to which they are otherwise resistant. In this study, we show that the antiapoptotic gene API5 acts as an immune escape gene in tumors by rendering them resistant to apoptosis triggered by tumor antigen-specific T cells. Its RNAi-mediated silencing in tumor cells expressing high levels of API5 restored antigen-specific immune sensitivity. Conversely, introducing API5 into API5(low) cells conferred immune resistance. Mechanistic investigations revealed that API5 mediated resistance by upregulating FGF2 signaling through a FGFR1/PKCδ/ERK effector pathway that triggered degradation of the proapoptotic molecule BIM. Blockade of FGF2, PKCδ, or ERK phenocopied the effect of API5 silencing in tumor cells expressing high levels of API5 to either murine or human antigen-specific T cells. Our results identify a novel mechanism of immune escape that can be inhibited to potentiate the efficacy of targeted active immunotherapies.

Naringin mitigates erythrocytes aging induced by paclitaxel: an in vitro study

In this study, the protective role of naringin (NAR) against paclitaxel (PTX)-induced erythrocytes aging has been investigated using human erythrocyte as an in vitro model. Erythrocytes were incubated with PTX in the presence and absence of NAR. Incubation of erythrocytes with PTX resulted in increased protein carbonyl content and malondialdehyde and hemolysis percentage compared with control. Furthermore, a significant increase in the ratios of glutathione peroxidase/glutathione reductase, superoxide dismutase/glutathione peroxidase, and superoxide dismutase/catalase in PTX-treated cells was observed, compared with control cells. In contrast, reduced glutathione/oxidized glutathione ratio and glucose-6-phosphate dehydrogenase activity were decreased upon PTX treatment. The simultaneous incubation of erythrocytes with PTX and NAR restored these variables to values similar to those of control erythrocytes. These results suggest that NAR inhibited PTX-induced aging by lessening the PTX-induced oxidative stress.

Bcl-2-enhanced efficacy of microtubule-targeting chemotherapy through Bim overexpression: implications for cancer treatment

Bcl-2 is commonly overexpressed in tumors, where it is often associated with unfavorable outcome. However, it has also been linked to a favorable sensitivity to microtubule-targeting agents (MTAs). We show that Bcl-2-overexpressing lung and breast cancer cells were more sensitive to both paclitaxel and vinorelbine. Bcl-2 over-expression also significantly potentiated in vivo efficacy of paclitaxel, in terms of tumor volume decrease and survival benefits, in models of nude mice bearing lung cancer xenografts. To further investigate this favorable effect of Bcl-2, a genomic approach was taken. It revealed that Bcl-2 overexpression induced up-regulation of the proapoptotic protein Bim in lung cancer cells and that, conversely, Bcl-2 silencing decreased Bim expression level. A gene regulation study implicated the transcription factor Forkhead box-containing protein, class O3a in Bim up-regulation. Lastly, we show that Bim was responsible for MTA-triggered lung cancer cell death through a dynamin-related protein 1-mediated mitochondrial fragmentation. The Bcl-2-governed Bim induction evidence offers for the first time an explanation for the favorable higher sensitivity to treatment shown by Bcl-2-overexpressing cells. We suggest that Bim could be a powerful predictive factor for tumor response to MTA chemotherapy. Our data also give new insight into some failures in the efficacy of therapies targeted against Bcl-2.

Inhibition of cancer cell proliferation and apoptosis-inducing activity of fungal taxol and its precursor baccatin III purified from endophytic Fusarium solani

Background

Taxol (generic name paclitaxel), a plant-derived antineoplastic agent, used widely against breast, ovarian and lung cancer, was originally isolated from the bark of the Pacific yew, Taxus brevifolia. The limited supply of the drug has prompted efforts to find alternative sources, such as chemical synthesis, tissue and cell cultures of the Taxus species both of which are expensive and yield low levels. Fermentation processes with microorganisms would be the methods of choice to lower the costs and increase yields. Previously we have reported that F. solani isolated from T. celebica produced taxol and its precursor baccatin III in liquid grown cultures J Biosci 33:259-67, 2008. This study was performed to evaluate the inhibition of proliferation and induction of apoptosis of cancer cell lines by the fungal taxol and fungal baccatin III of F. solani isolated from T. celebica.

Methods

Cell lines such as HeLa, HepG2, Jurkat, Ovcar3 and T47D were cultured individually and treated with fungal taxol, baccatin III with or without caspase inhibitors according to experimental requirements. Their efficacy on apoptotic induction was examined.

Results

Both fungal taxol and baccatin III inhibited cell proliferation of a number of cancer cell lines with IC₅₀ ranging from 0.005 to 0.2 μM for fungal taxol and 2 to 5 μM for fungal baccatin III. They also induced apoptosis in JR4-Jurkat cells with a possible involvement of anti-apoptotic Bcl2 and loss in mitochondrial membrane potential, and was unaffected by inhibitors of caspase-9,-2 or -3 but was prevented in presence of caspase-10 inhibitor. DNA fragmentation was also observed in cells treated with fungal taxol and baccatin III.

Conclusions

The cytotoxic activity exhibited by fungal taxol and baccatin III involves the same mechanism, dependent on caspase-10 and membrane potential loss of mitochondria, with taxol having far greater cytotoxic potential.

Mitosis and apoptosis: how is the balance set?

Anti-mitotic agents are used extensively during cancer chemotherapy. These agents target microtubules and thus block mitotic progression by activating the spindle assembly checkpoint. Following a prolonged mitotic arrest, cells either die in mitosis via apoptosis, or exit mitosis without dividing and survive, a process known as slippage. What dictates the balance between these two fates is unclear, but recent advances highlight the importance of the pro-survival Bcl2 family, with Mcl1 degradation emerging as a key determinant of mitotic cell fate. Here we review these advances, with a view towards identifying how the balance between apoptosis and slippage can be tipped in favour of death. This in turn may open up new opportunities to sensitize cancer cells to anti-mitotic agents.