The spindle checkpoint, aneuploidy, and cancer

The Impact of Pdcd4, a Translation Inhibitor, on Drug Resistance

Programmed cell death 4 (Pdcd4) is a tumor suppressor, which has been demonstrated to efficiently suppress tumorigenesis. Biochemically, Pdcd4 binds with translation initiation factor 4A and represses protein translation. Beyond its role in tumor suppression, growing evidence suggests that Pdcd4 enhances the chemosensitivity of several anticancer drugs. To date, numerous translational targets of Pdcd4 have been identified. These targets govern important signal transduction pathways, and their attenuation may improve chemosensitivity or overcome drug resistance. This review will discuss the signal transduction pathways regulated by Pdcd4 and the potential mechanisms through which Pdcd4 enhances chemosensitivity or counteracts drug resistance.

Activation of the PERK/eIF2α axis is a pivotal prerequisite of taxanes to cancer cell apoptosis and renders synergism to overcome paclitaxel resistance in breast cancer cells

BACKGROUND

Microtubule polymerization is usually considered as the upstream of apoptotic cell death induced by taxanes, but recently published studies provide more insights into the mechanisms responsible for the antineoplastic effect of taxanes. In this study, we figure out the role of the stress-related PERK/eIF2α axis in tumor cell death upon taxane treatment along with paclitaxel resistance.

METHODS

Utilizing immunoblot assay, the activation status of PERK-eIF2α signaling was detected in a panel of cancer cell lines after the treatment of taxanes. The causal role of PERK-eIF2α signaling in the cancer cell apoptosis induced by taxanes was examined via pharmacological and genetic inhibitions of PERK. The relationship between microtubule polymerization and PERK-eIF2α activation was explored by immunofluorescent and immunoblotting assays. Eventaually, the combined therapeutic effect of paclitaxel (PTX) and CCT020312, a PERK agonist, was investigated in PTX-resistant breast cancer cells in vitro and in vivo.

RESULTS

PERK-eIF2α axis was dramatically activated by taxanes in several cancer cell types. Pharmacological or genetic inhibition of PERK efficiently impaired taxane-induced apoptotic cell death, independent of the cellular microtubule polymerization status. Moreover, PTX was able to activate the PERK/eIF2α axis in a very low concentration without triggering microtubule polymerization. In PTX-resistant breast cancer cells, the PERK/eIF2α axis was attenuated in comparison with the PTX-sensitive counterparts. Reactivation of the PERK/eIF2α axis in the PTX-resistant breast cancer cells with PERK agonist sensitized them to PTX in vitro. Combination treatment of the xenografted PTX-resistant breast tumors with PERK agonist and PTX validated the synergic effect of PTX and PERK activation in vivo.

CONCLUSION

Activation of the PERK/eIF2α axis is a pivotal prerequisite of taxanes to initiate cancer cell apoptosis, which is independent of the well-known microtubule polymerization-dependent manner. Simultaneous activation of PERK-eIF2α signaling would be a promising therapeutic strategy to overcome PTX resistance in breast cancer or other cancers.

The crosstalk between non-coding RNAs and cell-cycle events: A new frontier in cancer therapy

The cell cycle comprises sequential events during which a cell duplicates its genome and divides it into two daughter cells. This process is tightly regulated to ensure that the daughter cell receives identical copied chromosomal DNA and that any errors in the DNA during replication are correctly repaired. Cyclins and their enzyme partners, cyclin-dependent kinases (CDKs), are critical regulators of G- to M-phase transitions during the cell cycle. Mitogenic signals induce the formation of the cyclin/CDK complexes, resulting in phosphorylation and activation of the CDKs. Once activated, cyclin/CDK complexes phosphorylate specific substrates that drive the cell cycle forward. The sequential activation and inactivation of cyclin-CDK complexes are tightly controlled by activating and inactivating phosphorylation events induced by cell-cycle proteins. The non-coding RNAs (ncRNAs), which do not code for proteins, regulate cell-cycle proteins at the transcriptional and translational levels, thereby controlling their expression at different cell-cycle phases. Deregulation of ncRNAs can cause abnormal expression patterns of cell-cycle-regulating proteins, resulting in abnormalities in cell-cycle regulation and cancer development. This review explores how ncRNA dysregulation can disrupt cell division balance and discusses potential therapeutic approaches targeting these ncRNAs to control cell-cycle events in cancer treatment.

The yin and yang of chromosomal instability in prostate cancer

Metastatic prostate cancer remains an incurable lethal disease. Studies indicate that prostate cancer accumulates genomic changes during disease progression and displays the highest levels of chromosomal instability (CIN) across all types of metastatic tumours. CIN, which refers to ongoing chromosomal DNA gain or loss during mitosis, and derived aneuploidy, are known to be associated with increased tumour heterogeneity, metastasis and therapy resistance in many tumour types. Paradoxically, high CIN levels are also proposed to be detrimental to tumour cell survival, suggesting that cancer cells must develop adaptive mechanisms to ensure their survival. In the context of prostate cancer, studies indicate that CIN has a key role in disease progression and might also offer a therapeutic vulnerability that can be pharmacologically targeted. Thus, a comprehensive evaluation of the causes and consequences of CIN in prostate cancer, its contribution to aggressive advanced disease and a better understanding of the acquired CIN tolerance mechanisms can translate into new tumour classifications, biomarker development and therapeutic strategies.

Chronic spindle assembly checkpoint activation causes myelosuppression and gastrointestinal atrophy

Interference with microtubule dynamics in mitosis activates the spindle assembly checkpoint (SAC) to prevent chromosome segregation errors. The SAC induces mitotic arrest by inhibiting the anaphase-promoting complex (APC) via the mitotic checkpoint complex (MCC). The MCC component MAD2 neutralizes the critical APC cofactor, CDC20, preventing exit from mitosis. Extended mitotic arrest can promote mitochondrial apoptosis and caspase activation. However, the impact of mitotic cell death on tissue homeostasis in vivo is ill-defined. By conditional MAD2 overexpression, we observe that chronic SAC activation triggers bone marrow aplasia and intestinal atrophy in mice. While myelosuppression can be compensated for, gastrointestinal atrophy is detrimental. Remarkably, deletion of pro-apoptotic Bim/Bcl2l11 prevents gastrointestinal syndrome, while neither loss of Noxa/Pmaip or co-deletion of Bid and Puma/Bbc3 has such a protective effect, identifying BIM as rate-limiting apoptosis effector in mitotic cell death of the gastrointestinal epithelium. In contrast, only overexpression of anti-apoptotic BCL2, but none of the BH3-only protein deficiencies mentioned above, can mitigate myelosuppression. Our findings highlight tissue and cell-type-specific survival dependencies in response to SAC perturbation in vivo.

Potential molecular mechanisms of Huangqin Tang for liver cancer treatment by network pharmacology and molecular dynamics simulations

OBJECTIVE

This study aims to investigate the mechanism of Huangqin Tang in treating liver cancer.

METHODS

Active ingredients and corresponding targets of Huangqin Tang were obtained from the Traditional Chinese Medicine Systems Pharmacology Database. Differentially expressed genes in liver cancer were identified from mRNA expression data. A protein-protein interaction (PPI) network was constructed using differentially expressed genes and Huangqin Tang targets. Random walk with restart (RWR) analysis was performed on the PPI network. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were conducted. A drug-active ingredient-gene interaction network was established, and molecular docking and molecular dynamics simulations were performed. Finally, the stability of binding between CDK1 and oroxylin was tested according to cellular thermal shift assay (CETSA).

RESULTS

160 active ingredients, 239 targets, and 1093 differentially expressed genes were identified. RWR analysis identified 10 potential targets for liver cancer. Enrichment analysis revealed protein kinase regulator activity and Steroid hormone biosynthesis as significant pathways. Molecular docking suggested a stable complex between oroxylin A and CDK1. CETSA demonstrated that the combination of oroxylin A and CDK1 increased the stability of CDK1, and the combination efficiency was high.

CONCLUSION

Huangqin Tang may treat liver cancer by targeting CDK1 with oroxylin A. Protein kinase regulator activity and Steroid hormone biosynthesis pathways may play a role in liver cancer treatment with Huangqin Tang. This study provides insight into the mechanistic basis of Huangqin Tang for liver cancer treatment.

Engineering small-molecule and protein drugs for targeting bone tumors

Bone cancer is common and severe. Both primary (e.g., osteosarcoma, Ewing sarcoma) and secondary (e.g., metastatic) bone cancers lead to significant health problems and death. Currently, treatments such as chemotherapy, hormone therapy, and radiation therapy are used to treat bone cancer, but they often only shrink or slow tumor growth and do not eliminate cancer completely. The bone microenvironment contributes unique signals that influence cancer growth, immunogenicity, and metastasis. Traditional cancer therapies have limited effectiveness due to off-target effects and poor distribution on bones. As a result, therapies with improved specificity and efficacy for treating bone tumors are highly needed. One of the most promising strategies involves the targeted delivery of pharmaceutical agents to the site of bone cancer by introduction of bone-targeting moieties, such as bisphosphonates or oligopeptides. These moieties have high affinities to the bone hydroxyapatite matrix, a structure found exclusively in skeletal tissue, and can enhance the targeting ability and efficacy of anticancer drugs when combating bone tumors. This review focuses on the engineering of small molecules and proteins with bone-targeting moieties for the treatment of bone tumors.

Spindle component 25 predicts the prognosis and the immunotherapy response of cancers: a pan-cancer analysis

Spindle component 25 (SPC25) is one of the four proteins that make up the nuclear division cycle 80 (NDC80) complex, the other three components being Ndc80p, Nuf2p, and spindle component 24. Deregulation of the components of this complex can lead to uncontrolled proliferation and reduced apoptosis. However, the prognostic and immunotherapeutic value of SPC25 in pan-cancer remains unclear. Data from the UCSC Xena, TIMER2.0, and TCGA were analyzed to investigate the overall differential expression of SPC25 across multiple cancer types. The survival prognosis, clinical features, and genetic changes of SPC25 were also evaluated. Finally, the relationship between SPC25 and immunotherapy response was further explored through Gene Set Enrichment Analysis, tumor microenvironment, and immune cell infiltration. The transcription and protein expression of SPC25 were significantly increased in most cancer types and had prognostic value for the survival of certain cancer patients such as ACC, CESC, KIRC, KIRP, LIHC, LUAD, MESO, STAD, THYM, and UCEC. In some cancer types, SPC25 expression was also markedly correlated with the TMB, MSI, and clinical characteristics. Gene Set Enrichment Analysis showed that SPC25 was significantly associated with immune-related pathways. In addition, it was also confirmed that the expression level of SPC25 was strongly correlated with immune cell infiltration, immune checkpoint genes, immune regulatory genes, Ferroptosis-related genes, Cuproptosis-related genes, and lactate metabolism-related genes. This study comprehensively explored the potential value of SPC25 as a prognostic and immunotherapeutic marker for pan-cancer, providing new direction and evidence for cancer therapy.

Redox modulation of oxidatively-induced DNA damage by ascorbate enhances both in vitro and ex-vivo DNA damage formation and cell death in melanoma cells

Elevated genomic instability in cancer cells suggests a possible model-scenario for their selective killing via the therapeutic delivery of well-defined levels of further DNA damage. To examine this scenario, this study investigated the potential for redox modulation of oxidatively-induced DNA damage by ascorbate in malignant melanoma (MM) cancer cells, to selectively enhance both DNA damage and MM cell killing. DNA damage was assessed by Comet and ɣH2AX assays, intracellular oxidising species by dichlorofluorescein fluorescence, a key antioxidant enzymatic defence by assessment of catalase activity and cell survival was determined by clonogenic assay. Comet revealed that MM cells had higher endogenous DNA damage levels than normal keratinocytes (HaCaT cells); this correlated MM cells having higher intracellular oxidising species and lower catalase activity, and ranked with MM cell melanin pigmentation. Comet also showed MM cells more sensitive towards the DNA damaging effects of exogenous H2O2, and that ascorbate further enhanced this H2O2-induced damage in MM cells; again, with MM cell sensitivity to induced damage ranking with degree of cell pigmentation. Furthermore, cell survival data indicated that ascorbate enhanced H2O2-induced clonogenic cell death selectively in MM cells whilst protecting HaCaT cells. Finally, we show that ascorbate serves to enhance the oxidising effects of the MM therapeutic drug Elesclomol in both established MM cells in vitro and primary cell cultures ex vivo. Together, these results suggest that ascorbate selectively enhances DNA damage and cell-killing in MM cells. This raises the option of incorporating ascorbate into clinical oxidative therapies to treat MM.

Drivers of cancer metastasis - Arise early and remain present

Cancer and its metastases arise from mutations of genes, drivers that promote a tumor's growth. Analyses of driver events provide insights into cancer cell history and may lead to a better understanding of oncogenesis. We reviewed 27 metastatic research studies, including pan-cancer studies, individual cancer studies, and phylogenetic analyses, and summarized our current knowledge of metastatic drivers. All of the analyzed studies had a high level of consistency of driver mutations between primary tumors and metastasis, indicating that most drivers appear early in cancer progression and are maintained in metastatic cells. Additionally, we reviewed data from around 50,000 metastatic cancer patients and compiled a list of genes altered in metastatic lesions. We performed Gene Ontology analysis and confirmed that the most significantly enriched processes in metastatic lesions were the epigenetic regulation of gene expression, signal transduction, cell cycle, programmed cell death, DNA damage, hypoxia and EMT. In this review, we explore the most recent discoveries regarding genetic factors in the advancement of cancer, specifically those that drive metastasis.

Distinct characteristics of the DNA damage response in mammalian oocytes

DNA damage is a critical threat that poses significant challenges to all cells. To address this issue, cells have evolved a sophisticated molecular and cellular process known as the DNA damage response (DDR). Among the various cell types, mammalian oocytes, which remain dormant in the ovary for extended periods, are particularly susceptible to DNA damage. The occurrence of DNA damage in oocytes can result in genetic abnormalities, potentially leading to infertility, birth defects, and even abortion. Therefore, understanding how oocytes detect and repair DNA damage is of paramount importance in maintaining oocyte quality and preserving fertility. Although the fundamental concept of the DDR is conserved across various cell types, an emerging body of evidence reveals striking distinctions in the DDR between mammalian oocytes and somatic cells. In this review, we highlight the distinctive characteristics of the DDR in oocytes and discuss the clinical implications of DNA damage in oocytes.

TTK/MPS1 inhibitor OSU-13 targets the mitotic checkpoint and is a potential therapeutic strategy for myeloma

Despite substantial recent advances in treatment, multiple myeloma (MM) remains an incurable disease, with a shortage of treatment options for patients with high-risk disease, warranting the need for novel therapeutic targets and treatment approaches. Threonine and tyrosine kinase (TTK), also known as monopolar spindle 1 (MPS1), is a kinase essential for the mitotic spindle checkpoint whose expression correlates to unfavorable prognosis in several cancers. Here, we report the importance of TTK in MM, and the effects of the TTK inhibitor OSU-13. Elevated TTK expression correlated with amplification/ gain of 1q21 and decreased overall and event-free survival in MM. Treatment with OSU-13 inhibited TTK activity efficiently and selectively at a similar concentration range to other TTK inhibitor clinical candidates. OSU-13 reduced proliferation and viability of primary human MM cells and cell lines, especially those with high 1q21 copy numbers, and triggered apoptosis through caspase 3 and 7 activation. In addition, OSU-13 induced DNA damage and severe defects in chromosome alignment and segregation, generating aneuploidy. In vivo, OSU-13 decreased tumor growth in mice with NCI-H929 xenografts. Collectively, our findings reveal that inhibiting TTK with OSU-13 is a potential therapeutic strategy for MM, particularly for a subset of high-risk patients with poor outcome.

Drug Screening Using Normal Cell and Cancer Cell Mixture in an Automated 3D Cell Culture System

Three-dimensional (3D) cell culture creates a more physiologically relevant environment for enhanced drug screening capabilities using microcarriers. An automated 3D system that integrates robotic manipulators, liquid handling systems, sensors, and environment control systems has the capacity to handle multiple samples in parallel, perform repetitive tasks, and provide real-time monitoring and analysis. This chapter describes a potential 3D cell culture drug screening model by combining renal proximal tubule cells as a representative normal cell line with cancer cell lines. This combination is subjected to drug screening to evaluate the drug's efficacy in suppressing cancer cells while minimizing impact on normal cells with the added benefit of having the ability to separate the two cell types by magnetic isolation for high content screens including mass spectrometry-based proteomics. This study presents advancements in 3D cell culture techniques, emphasizing the importance of automation and the potential of microcarriers in drug screening and disease modeling.

Unlocking the synthetic approaches and clinical application of approved small-molecule drugs for gastrointestinal cancer treatment: A comprehensive exploration

Gastrointestinal (GI) cancers encompass a group of malignancies affecting the digestive system, including the stomach, esophagus, liver, colon, rectum and pancreas. These cancers represent a significant global health burden, necessitating effective treatment strategies. Small-molecule drugs have emerged as crucial therapeutic options in the fight against GI cancers due to their oral bioavailability, targeted mechanisms of action, and well-established safety profiles. The review then elucidates the clinical applications and synthetic methods of clinically approved small-molecule drugs for the treatment of GI cancer, shedding light on their mechanisms of action and their potential in mitigating GI cancer progression. The review also discusses future prospects and the evolving landscape of small-molecule drug development in GI oncology, highlighting the potential for personalized medicine. In summary, this review provides valuable insights into cutting-edge strategies for harnessing clinically approved small-molecule drugs to combat GI cancer effectively.

Single-cell multi-omics sequencing reveals chromosome copy number inconsistency between trophectoderm and inner cell mass in human reconstituted embryos after spindle transfer

STUDY QUESTION

Is the chromosome copy number of the trophectoderm (TE) of a human reconstituted embryos after spindle transfer (ST) representative of the inner cell mass (ICM)?

SUMMARY ANSWER

Single-cell multi-omics sequencing revealed that ST blastocysts have a higher proportion of cell lineages exhibiting intermediate mosaicism than conventional ICSI blastocysts, and that the TE of ST blastocysts does not represent the chromosome copy number of ICM.

WHAT IS KNOWN ALREADY

Preimplantation genetic testing for aneuploidy (PGT-A) assumes that TE biopsies are representative of the ICM, but the TE and ICM originate from different cell lineages, and concordance between TE and ICM is not well-studied, especially in ST embryos.

STUDY DESIGN, SIZE, DURATION

We recruited 30 infertile women who received treatment at our clinic and obtained 45 usable blastocysts (22 from conventional ICSI and 23 reconstituted embryos after ST). We performed single-cell multi-omics sequencing on all blastocysts to predict and verify copy number variations (CNVs) in each cell. We determined the chromosome copy number of each embryo by analysing the proportion of abnormal cells in each blastocyst. We used the Bland-Altman concordance and the Kappa test to evaluate the concordance between TE and ICM in the both groups.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at a public tertiary hospital in China, where all the embryo operations, including oocytes retrieval, ST, and ICSI, were performed in the embryo laboratory. We utilized single-cell multi-omics sequencing technology at the Biomedical Pioneering Innovation Center, School of Life Sciences, Peking University, to analyse the blastocysts. Transcriptome sequencing was used to predict the CNV of each cell through bioinformatics analysis, and the results were validated using the DNA methylation library of each cell to confirm chromosomal normalcy. We conducted statistical analysis and graphical plotting using R 4.2.1, SPSS 27, and GraphPad Prism 9.3.

MAIN RESULTS AND THE ROLE OF CHANCE

Mean age of the volunteers, the blastocyst morphology, and the developmental ratewere similar in ST and ICSI groups. The blastocysts in the ST group had some additional chromosomal types that were prone to variations beyond those enriched in the blastocysts of the ICSI group. Finally, both Bland-Altman concordance test and kappa concordancetest showed good chromosomal concordance between TE and ICM in the ICSI blastocysts (kappa = 0.659, P < 0.05), but not in ST blastocysts (P = 1.000), suggesting that the TE in reconstituted embryos is not representative of ICM. Gene functional annotation (GO and KEGG analyses) suggests that there may be new or additional pathways for CNV generation in ST embryos compared to ICSI embryos.

LIMITATIONS, REASONS FOR CAUTION

This study was mainly limited by the small sample size and the limitations of single-cell multi-omics sequencing technology. To select eligible single cells, some cells of the embryos were eliminated or not labelled, resulting in a loss of information about them. The findings of this study are innovative and exploratory. A larger sample size of human embryos (especially ST embryos) and more accurate molecular genetics techniques for detecting CNV in single cells are needed to validate our results.

WIDER IMPLICATIONS OF THE FINDINGS

Our study justifies the routine clinical use of PGT-A in ICSI blastocysts, as we found that the TE is a good substitute for ICM in predicting chromosomal abnormalities. While PGT-A is not entirely accurate, our data demonstrate good clinical feasibility. This trial was able to provide correct genetic counselling to patients regarding the reliability of PGT-A. Regarding ST blastocysts, the increased mosaicism rate and the inability of the TE to represent the chromosomal copy number of the ICM are both biological characteristics that differentiate them from ICSI blastocysts. Currently, ST is not used clinically on a large scale to produce blastocysts. However, if ST becomes more widely used in the future, our study will be the first to demonstrate that the use of PGT-A in ST blastocysts may not be as accurate as PGT-A for ICSI blastocysts.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by grants from the National Key R&D Program of China (2018YFA0107601) and the National Key R&D Program of China (2018YFC1003003). The authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Chrysin attenuates paclitaxel-induced hepatorenal toxicity in rats by suppressing oxidative damage, inflammation, and apoptosis

AIMS

Paclitaxel (Pax) is a chemotherapeutic drug from the taxane family that is used in the treatment of human cancer, including ovarian, breast, and non-small cell lung carcinoma. Chrysin (CR) has antioxidant, anti-inflammatory, anti-apoptotic, anti-diabetic, and anti-carcinogenic properties, as well as hepatoprotective and renoprotective activities. In the present study, we evaluated the protective effect of CR against Pax-induced hepatorenal toxicity on inflammation, apoptosis, antioxidant levels, oxidative DNA damage, and histopathology in rats.

MATERIAL AND METHODS

Thirty-five male Sprague-Dawley rats were divided into five groups (n = 7): Group I (normal control), Group II (CR alone at a dose of 50 mg/kg), Group III (Pax at a dose of 2 mg/kg), Group IV (Pax+CR 25), and Group V (Pax+CR 50). The expressions of apoptotic (Bax and Bcl-2) and antioxidant genes (SOD1, CAT, GPx3, and GST) were evaluated using RT-PCR from paraffin sections. Caspase 3, KIM-1, NF-kB, COX-2, and 8-OHdG were also determined by immunohistochemical examination.

KEY FINDINGS

The results revealed that Pax exposure caused hepatic and renal damage in rats, which was indicated by a significant elevation of caspase 3, Bax, KIM-1, NF-kB, COX-2, and 8-OHdG. However, there was a marked downregulation in the expressions of the Bcl-2, SOD1, CAT, GPx3, and GST genes. In contrast, rats given CR in combination showed better gene expression, histological structure, and immunohistochemical staining results.

SIGNIFICANCE

Consequently, CR exhibited the ability to reduce oxidative DNA damage, exert anti-apoptotic and anti-inflammatory properties, and mitigate the toxic effects of Pax-induced hepatorenal toxicity.

Pleiotropy of autism-associated chromatin regulators

Gene ontology analyses of high-confidence autism spectrum disorder (ASD) risk genes highlight chromatin regulation and synaptic function as major contributors to pathobiology. Our recent functional work in vivo has additionally implicated tubulin biology and cellular proliferation. As many chromatin regulators, including the ASD risk genes ADNP and CHD3, are known to directly regulate both tubulins and histones, we studied the five chromatin regulators most strongly associated with ASD (ADNP, CHD8, CHD2, POGZ and KMT5B) specifically with respect to tubulin biology. We observe that all five localize to microtubules of the mitotic spindle in vitro in human cells and in vivo in Xenopus. Investigation of CHD2 provides evidence that mutations present in individuals with ASD cause a range of microtubule-related phenotypes, including disrupted localization of the protein at mitotic spindles, cell cycle stalling, DNA damage and cell death. Lastly, we observe that ASD genetic risk is significantly enriched among tubulin-associated proteins, suggesting broader relevance. Together, these results provide additional evidence that the role of tubulin biology and cellular proliferation in ASD warrants further investigation and highlight the pitfalls of relying solely on annotated gene functions in the search for pathological mechanisms.

Chromosomal instability and its effect on cell lines

BACKGROUND

Cancer cell lines are invaluable model systems for biomedical research because they provide an almost unlimited supply of biological materials. However, there is considerable skepticism regarding the reproducibility of data derived from these in vitro models.

RECENT FINDINGS

Chromosomal instability (CIN) is one of the primary issues associated with cell lines, which can cause genetic heterogeneity and unstable cell properties within a cell population. Many of these problems can be avoided with some precautions. Here we review the underlying causes of CIN, including merotelic attachment, telomere dysfunction, DNA damage response defects, mitotic checkpoint defects and cell cycle disturbances.

CONCLUSION

In this review we summarize studies highlighting the consequences of CIN in various cell lines and provide suggestions on monitoring and controlling CIN during cell culture.

The critical role of circular RNAs in drug resistance in gastrointestinal cancers

Nowadays, drug resistance (DR) in gastrointestinal (GI) cancers, as the main reason for cancer-related mortality worldwide, has become a serious problem in the management of patients. Several mechanisms have been proposed for resistance to anticancer drugs, including altered transport and metabolism of drugs, mutation of drug targets, altered DNA repair system, inhibited apoptosis and autophagy, cancer stem cells, tumor heterogeneity, and epithelial-mesenchymal transition. Compelling evidence has revealed that genetic and epigenetic factors are strongly linked to DR. Non-coding RNA (ncRNA) interferences are the most crucial epigenetic alterations explored so far, and among these ncRNAs, circular RNAs (circRNAs) are the most emerging members known to have unique properties. Due to the absence of 5' and 3' ends in these novel RNAs, the two ends are covalently bonded together and are generated from pre-mRNA in a process known as back-splicing, which makes them more stable than other RNAs. As far as the unique structure and function of circRNAs is concerned, they are implicated in proliferation, migration, invasion, angiogenesis, metastasis, and DR. A clear understanding of the molecular mechanisms responsible for circRNAs-mediated DR in the GI cancers will open a new window to the management of GI cancers. Hence, in the present review, we will describe briefly the biogenesis, multiple features, and different biological functions of circRNAs. Then, we will summarize current mechanisms of DR, and finally, discuss molecular mechanisms through which circRNAs regulate DR development in esophageal cancer, pancreatic cancer, gastric cancer, colorectal cancer, and hepatocellular carcinoma.

Polyploid giant cancer cells and cancer progression

Polyploid giant cancer cells (PGCCs) are an important feature of cellular atypia, the detailed mechanisms of their formation and function remain unclear. PGCCs were previously thought to be derived from repeated mitosis/cytokinesis failure, with no intrinsic ability to proliferate and divide. However, recently, PGCCs have been confirmed to have cancer stem cell (CSC)-like characteristics, and generate progeny cells through asymmetric division, which express epithelial-mesenchymal transition-related markers to promote invasion and migration. The formation of PGCCs can be attributed to multiple stimulating factors, including hypoxia, chemotherapeutic reagents, and radiation, can induce the formation of PGCCs, by regulating the cell cycle and cell fusion-related protein expression. The properties of CSCs suggest that PGCCs can be induced to differentiate into non-tumor cells, and produce erythrocytes composed of embryonic hemoglobin, which have a high affinity for oxygen, and thereby allow PGCCs survival from the severe hypoxia. The number of PGCCs is associated with metastasis, chemoradiotherapy resistance, and recurrence of malignant tumors. Targeting relevant proteins or signaling pathways related with the formation and transdifferentiation of adipose tissue and cartilage in PGCCs may provide new strategies for solid tumor therapy.

Analysis of the potential role of fission yeast PP2A in spindle assembly checkpoint inactivation

As a surveillance mechanism, the activated spindle assembly checkpoint (SAC) potently inhibits the E3 ubiquitin ligase APC/C (anaphase-promoting complex/cyclosome) to ensure accurate chromosome segregation. Although the protein phosphatase 2A (PP2A) has been proposed to be both, directly and indirectly, involved in spindle assembly checkpoint inactivation in mammalian cells, whether it is similarly operating in the fission yeast Schizosaccharomycer pombe has never been demonstrated. Here, we investigated whether fission yeast PP2A is involved in SAC silencing by following the rate of cyclin B (Cdc13) destruction at SPBs during the recovery phase in nda3-KM311 cells released from the inhibition of APC/C by the activated spindle checkpoint. The timing of the SAC inactivation is only slightly delayed when two B56 regulatory subunits (Par1 and Par2) of fission yeast PP2A are absent. Overproduction of individual PP2A subunits either globally in the nda3-KM311 arrest-and-release system or locally in the synthetic spindle checkpoint activation system only slightly suppresses the SAC silencing defects in PP1 deletion (dis2Δ) cells. Our study thus demonstrates that the fission yeast PP2A is not a key regulator actively involved in SAC inactivation.

Englerin A Rewires Phosphosignaling via Hsp27 Hyperphosphorylation to Induce Cytotoxicity in Renal Cancer Cells

Englerin A (EA) is a small-molecule natural product with selective cytotoxicity against renal cancer cells. EA has been shown to induce apoptosis and cell death through cell-cycle arrest and/or insulin signaling pathways. However, its biological mode of action or targets in renal cancer remains enigmatic. In this study, we employed advanced mass spectrometry-based phosphoproteomics approaches to identify EA's functional roles in renal cancer. We identified 10,940 phosphorylation sites, of which 706 sites exhibited EA-dependent phosphorylation changes. Integrated analysis of motifs and interaction networks suggested activation of stress-activated kinases including p38 upon EA treatment. Of note, a downstream target of p38, Hsp27, was found to be hyperphosphorylated on multiple sites upon EA treatment. Among these, a novel site Ser65 on Hsp27, which was further validated by targeted proteomics, was shown to be crucial for EA-induced cytotoxicity in renal cancer cells. Taken together, these data reveal the complex signaling cascade that is induced upon EA treatment and importantly provide insights into its effects on downstream molecular signaling.

Phosphorylation of MAD2 at Ser195 Promotes Spindle Checkpoint Defects and Sensitizes Cancer Cells to Radiotherapy in ATM Deficient Cells

The spindle assembly checkpoint (SAC) is a critical monitoring device in mitosis for the maintenance of genomic stability. Specifically, the SAC complex comprises several factors, including Mad1, Mad2, and Bub1. Ataxia-telangiectasia mutated (ATM) kinase, the crucial regulator in DNA damage response (DDR), also plays a critical role in mitosis by regulating Mad1 dimerization and SAC. Here, we further demonstrated that ATM negatively regulates the phosphorylation of Mad2, another critical component of the SAC, which is also involved in DDR. Mechanistically, we found that phosphorylation of Mad2 is aberrantly increased in ATM-deficient cells. Point-mutation analysis further revealed that Serine 195 mainly mediated Mad2 phosphorylation upon ATM ablation. Functionally, the phosphorylation of Mad2 causes decreased DNA damage repair capacity and is related to the resistance to cancer cell radiotherapy. Altogether, this study unveils the key regulatory role of Mad2 phosphorylation in checkpoint defects and DNA damage repair in ATM-deficient cells.

TORC1 inactivation promotes APC/C-dependent mitotic slippage in yeast and human cells

Unsatisfied kinetochore-microtubule attachment activates the spindle assembly checkpoint to inhibit the metaphase-anaphase transition. However, some cells eventually override mitotic arrest by mitotic slippage. Here, we show that inactivation of TORC1 kinase elicits mitotic slippage in budding yeast and human cells. Yeast mitotic slippage was accompanied with aberrant aspects, such as degradation of the nucleolar protein Net1, release of phosphatase Cdc14, and anaphase-promoting complex/cyclosome (APC/C)-Cdh1-dependent degradation of securin and cyclin B in metaphase. This mitotic slippage caused chromosome instability. In human cells, mammalian TORC1 (mTORC1) inactivation also invoked mitotic slippage, indicating that TORC1 inactivation-induced mitotic slippage is conserved from yeast to mammalian cells. However, the invoked mitotic slippage in human cells was not dependent on APC/C-Cdh1. This study revealed an unexpected involvement of TORC1 in mitosis and provides information on undesirable side effects of the use of TORC1 inhibitors as immunosuppressants and anti-tumor drugs.

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Yeast TORC1 inhibition promotes Net1 degradation and Cdc14 release

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Yeast TORC1 inhibition invokes mitotic slippage in an APC/C-Cdh1-dependent manner

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Human mTORC1 inhibition also elicits mitotic slippage

Targeting Cell Cycle Checkpoint Kinases to Overcome Intrinsic Radioresistance in Brain Tumor Cells

Simple Summary

As cell cycle checkpoint mechanisms maintain genomic integrity, the inhibition of enzymes involved in these control mechanisms may increase the sensitivity of the cells to DNA damaging treatments. In this review, we summarize the knowledge in the field of brain tumor treatment with radiation therapy and cell cycle checkpoint inhibition via targeting ATM, ATR, CHK1, CHK2, and WEE1 kinases.

Abstract

Radiation therapy is an important part of the standard of care treatment of brain tumors. However, the efficacy of radiation therapy is limited by the radioresistance of tumor cells, a phenomenon held responsible for the dismal prognosis of the most aggressive brain tumor types. A promising approach to radiosensitization of tumors is the inhibition of cell cycle checkpoint control responsible for cell cycle progression and the maintenance of genomic integrity. Inhibition of the kinases involved in these control mechanisms can abolish cell cycle checkpoints and DNA damage repair and thus increase the sensitivity of tumor cells to radiation and chemotherapy. Here, we discuss preclinical progress in molecular targeting of ATM, ATR, CHK1, CHK2, and WEE1, checkpoint kinases in the treatment of brain tumors, and review current clinical phase I-II trials.

Knockout of caspase-7 gene improves the expression of recombinant protein in CHO cell line through the cell cycle arrest in G2/M phase

Background

Chinese hamster ovary cell line has been used routinely as a bioproduction factory of numerous biopharmaceuticals. So far, various engineering strategies have been recruited to improve the production efficiency of this cell line such as apoptosis engineering. Previously, it is reported that the caspase-7 deficiency in CHO cells reduces the cell proliferation rate. But the effect of this reduction on the CHO cell productivity remained unclear. Hence, in the study at hand the effect of caspase-7 deficiency was assessed on the cell growth, viability and protein expression. In addition, the enzymatic activity of caspase-3 was investigated in the absence of caspase-7.

Results

Findings showed that in the absence of caspase-7, both cell growth and cell viability were decreased. Cell cycle analysis illustrated that the CHO knockout (CHO-KO) cells experienced a cell cycle arrest in G2/M phase. This cell cycle arrest resulted in a 1.7-fold increase in the expression of luciferase in CHO-KO cells compared to parenteral cells. Furthermore, in the apoptotic situation the enzymatic activity of caspase-3 in CHO-KO cells was approximately 3 times more than CHO-K1 cells.

Conclusions

These findings represented that; however, caspase-7 deficiency reduces the cell proliferation rate but the resulted cell cycle arrest leads to the enhancement of recombinant protein expression. Moreover, increasing in the caspase-3 enzymatic activity compensates the absence of caspase-7 in the caspase cascade of apoptosis.

Bioinformatics Analysis of Prognostic Value of SPC24 in ccRCC and Pan-Cancer

Purpose

Clear cell renal cell carcinoma (ccRCC) is one of the most common diseases in the world, with high morbidity and mortality. Recent studies have revealed the important role of SPC24, a subunit of the Ndc80 complex, in the occurrence and development of carcinoma. However, the latent effect of SPC24 in the progress of ccRCC remains to be further explored. The intent of this research is to investigate whether SPC24 can be used as an index to predict the progression of ccRCC and to explore its relationship with the immune microenvironment and pan-cancer.

Materials and Methods

Based on data from public databases, we determined the expression level and clinical value of SPC24 in ccRCC and human pan-cancer. RT-qPCR analysis was carried out to detect the expression level of SPC24 in the OSRC/786O (human ccRCC cells) cell lines and HK2 (human normal kidney cells) cell line. The signal transduction pathways activated by different levels of SPC24 expression were explored by Gene Set Enrichment Analysis (GSEA), and the CIBERSORT algorithm was applied to analyze the relationship between infiltrating immune cells and SPC24 expression in ccRCC and pan-cancer tissues.

Results

SPC24 is overexpressed in ccRCC and several types of tumors, which is associated with poor prognosis. GSEA and CIBERSORT algorithms suggested that the high expression group of SPC24 enriched various pathways including immune-related pathways, and the several infiltrated immunocytes were related to the expression of SPC24.

Conclusion

Our study revealed that SPC24 is a prognostic factor in ccRCC related to immunomodulation and has generalized value in pan-cancer.

The Hippo Signaling Pathway in Cancer: A Cell Cycle Perspective

Simple Summary

Cancer is increasingly viewed as a cell cycle disease in that the dysregulation of the cell cycle machinery is a common feature in cancer. The Hippo signaling pathway consists of a core kinase cascade as well as extended regulators, which together control organ size and tissue homeostasis. The aberrant expression of cell cycle regulators and/or Hippo pathway components contributes to cancer development, and for this reason, we specifically focus on delineating the roles of the Hippo pathway in the cell cycle. Improving our understanding of the Hippo pathway from a cell cycle perspective could be used as a powerful weapon in the cancer battlefield.

Abstract

Cell cycle progression is an elaborate process that requires stringent control for normal cellular function. Defects in cell cycle control, however, contribute to genomic instability and have become a characteristic phenomenon in cancers. Over the years, advancement in the understanding of disrupted cell cycle regulation in tumors has led to the development of powerful anti-cancer drugs. Therefore, an in-depth exploration of cell cycle dysregulation in cancers could provide therapeutic avenues for cancer treatment. The Hippo pathway is an evolutionarily conserved regulator network that controls organ size, and its dysregulation is implicated in various types of cancers. Although the role of the Hippo pathway in oncogenesis has been widely investigated, its role in cell cycle regulation has not been comprehensively scrutinized. Here, we specifically focus on delineating the involvement of the Hippo pathway in cell cycle regulation. To that end, we first compare the structural as well as functional conservation of the core Hippo pathway in yeasts, flies, and mammals. Then, we detail the multi-faceted aspects in which the core components of the mammalian Hippo pathway and their regulators affect the cell cycle, particularly with regard to the regulation of E2F activity, the G1 tetraploidy checkpoint, DNA synthesis, DNA damage checkpoint, centrosome dynamics, and mitosis. Finally, we briefly discuss how a collective understanding of cell cycle regulation and the Hippo pathway could be weaponized in combating cancer.

Identification of novel biomarkers in breast cancer via integrated bioinformatics analysis and experimental validation

Breast cancer (BC), an extremely aggressive malignant tumor, causes a large number of deaths worldwide. In this study, we pooled profile datasets from three cohorts to illuminate the underlying key genes and pathways of BC. Expression profiles GSE42568, GSE45827, and GSE124646, including 244 BC tissues and 28 normal breast tissues, were integrated and analyzed. Differentially expressed genes (DEGs) were screened out based on these three datasets. Functional analysis including Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway were performed using The Database for Annotation, Visualization and Integrated Discovery (DAVID). Moreover, Cytoscape with Search Tool for the Retrieval of Interacting Genes (STRING) and Molecular Complex Detection (MCODE) plugin were utilized to visualize protein protein interaction (PPI) of these DEGs. The module with the highest connectivity of gene interactions was selected for further analysis. All of these hub genes had a significantly worse prognosis in BC by survival analysis. Additionally, four genes (CDK1, CDC20, AURKA, and MCM4) dramatically were enriched in oocyte meiosis and cell cycle pathways through re-analysis of DAVID. Moreover, the mRNA and protein levels of CDK1, CDC20, AURKA, and MCM4 were significantly increased in BC patients. In addition, knockdown of CDK1 and CDC20 by small interfering RNA remarkably suppressed cell migration and invasion in MCF-7 and MDA-MB-231 cells. In conclusion, our results suggested that CDK1, CDC20, AURKA, and MCM4 were reliable biomarkers of BC via bioinformatics analysis and experimental validation and may act as prospective targets for BC diagnosis and treatment.

Increased SPC24 in prostatic diseases and diagnostic value of SPC24 and its interacting partners in prostate cancer

SPC24 is a crucial component of the mitotic checkpoint machinery in tumorigenesis. High levels of SPC24 have been found in various cancers, including breast cancer, lung cancer, liver cancer, osteosarcoma and thyroid cancer. However, to the best of our knowledge, the impact of SPC24 on prostate cancer (PCa) and other prostate diseases remains unclear. In the present study expression of global SPC24 messenger RNA (mRNA) was assessed in a subset of patients with PCa included in The Cancer Genome Atlas (TCGA) database. Increased levels of SPC24 expression were found in PCa patients >60 years old compared to patients <60 and increased SPC24 expression was also associated with higher levels of prostate specific antigen (P<0.05) and lymph node metastasis (P<0.05). Higher levels of SPC24 expression were associated with negative outcomes in PCa patients (P<0.05). Furthermore, in Chinese patients with prostatitis, benign prostatic hypertrophy (BPH) and PCa, SPC24 was expressed at significantly higher levels than that in adjacent/normal tissues, as assessed by reverse transcription-quantitative polymerase chain reaction, immunohistochemistry and western blotting. High expression of SPC24 was associated with high Gleason stages (IV and V; P<0.05). Further analysis, based on Gene Ontology and pathway functional enrichment analysis, suggested that nuclear division cycle 80 (NDC80), an SPC24 protein interaction partner, and mitotic spindle checkpoint serine/threonine-protein kinase BUB1 (BUB1), a core subunit of the spindle assembly checkpoint, may be associated with SPC24 in PCa development. Finally, using binary logistic regression, algorithms combining the receiver operating characteristic between SPC24 and BUB1 or NDC80 indicated that a combination of these markers may provide better PCa diagnosis ability than other PCa diagnosis markers. Taken together, these findings suggest that SPC24 may be a promising prostate disease biomarker.

Polyploid mitosis and depolyploidization promote chromosomal instability and tumor progression in a Notch-induced tumor model

Ploidy variation is a cancer hallmark and is frequently associated with poor prognosis in high-grade cancers. Using a Drosophila solid-tumor model where oncogenic Notch drives tumorigenesis in a transition-zone microenvironment in the salivary gland imaginal ring, we find that the tumor-initiating cells normally undergo endoreplication to become polyploid. Upregulation of Notch signaling, however, induces these polyploid transition-zone cells to re-enter mitosis and undergo tumorigenesis. Growth and progression of the transition-zone tumor are fueled by a combination of polyploid mitosis, endoreplication, and depolyploidization. Both polyploid mitosis and depolyploidization are error prone, resulting in chromosomal copy-number variation and polyaneuploidy. Comparative RNA-seq and epistasis analysis reveal that the DNA-damage response genes, also active during meiosis, are upregulated in these tumors and are required for the ploidy-reduction division. Together, these findings suggest that polyploidy and associated cell-cycle variants are critical for increased tumor-cell heterogeneity and genome instability during cancer progression.

The Involvement of Ubiquitination Machinery in Cell Cycle Regulation and Cancer Progression

The cell cycle is a collection of events by which cellular components such as genetic materials and cytoplasmic components are accurately divided into two daughter cells. The cell cycle transition is primarily driven by the activation of cyclin-dependent kinases (CDKs), which activities are regulated by the ubiquitin-mediated proteolysis of key regulators such as cyclins, CDK inhibitors (CKIs), other kinases and phosphatases. Thus, the ubiquitin-proteasome system (UPS) plays a pivotal role in the regulation of the cell cycle progression via recognition, interaction, and ubiquitination or deubiquitination of key proteins. The illegitimate degradation of tumor suppressor or abnormally high accumulation of oncoproteins often results in deregulation of cell proliferation, genomic instability, and cancer occurrence. In this review, we demonstrate the diversity and complexity of the regulation of UPS machinery of the cell cycle. A profound understanding of the ubiquitination machinery will provide new insights into the regulation of the cell cycle transition, cancer treatment, and the development of anti-cancer drugs.

Molecular Mechanisms of Chemotherapy Resistance in Head and Neck Cancers

Chemotherapy resistance is a huge barrier for head and neck cancer (HNC) patients and therefore requires close attention to understand its underlay mechanisms for effective strategies. In this review, we first summarize the molecular mechanisms of chemotherapy resistance that occur during the treatment with cisplatin, 5-fluorouracil, and docetaxel/paclitaxel, including DNA/RNA damage repair, drug efflux, apoptosis inhibition, and epidermal growth factor receptor/focal adhesion kinase/nuclear factor-κB activation. Next, we describe the potential approaches to combining conventional therapies with previous cancer treatments such as immunotherapy, which may improve the treatment outcomes and prolong the survival of HNC patients. Overall, by parsing the reported molecular mechanisms of chemotherapy resistance within HNC patient’s tumors, we can improve the prediction of chemotherapeutic responsiveness, and reveal new therapeutic targets for the future.

Matrix Metalloproteinase-9-Responsive Surface Charge-Reversible Nanocarrier to Enhance Endocytosis as Efficient Targeted Delivery System for Cancer Diagnosis and Therapy

Nanoparticles, that can be enriched in the tumor microenvironment and deliver the payloads into cancer cells, are desirable carriers for theranostic agents in cancer diagnosis and treatment. However, efficient targeted delivery and enhanced endocytosis for probes and drugs in theranostics are still major challenges. Here, a nanoparticle, which is capable of charge reversal from negative to positive in response to matrix metalloproteinase 9 (MMP9) in tumor microenvironment is reported. This nanoparticle is based on a novel charge reversible amphiphilic molecule consisting of hydrophobic oleic acid, MMP9-cleavable peptide, and glutamate-rich segment (named as OMPE). The OMPE-modified cationic liposome forms an intelligent anionic nanohybrid (O-NP) with enhanced endocytosis through surface charge reversal in response to MMP9 in vitro. Successfully, O-NP nanohybrid performs preferential accumulation and enhances the endocytosis in MMP9-expressing xenografted tumors in mouse models, which improve the sensitivity of diagnosis agents and the antitumor effects of drugs in vivo by overcoming their low solubility and/or nonspecific enrichment. These results indicate that O-NP can be a promising delivery platform for cancer diagnosis and therapy.

A five-m6A regulatory gene signature is a prognostic biomarker in lung adenocarcinoma patients

We analyzed the prognostic value of N6-methyladenosine (m6A) regulatory genes in lung adenocarcinoma (LADC) and their association with tumor immunity and immunotherapy response. Seventeen of 20 m6A regulatory genes were differentially expressed in LDAC tissue samples from the TCGA and GEO databases. We developed a five-m6A regulatory gene prognostic signature based on univariate and Lasso Cox regression analysis. Western blot analysis confirmed that the five prognostic m6A regulatory proteins were highly expressed in LADC tissues. We constructed a nomogram with five-m6A regulatory gene prognostic risk signature and AJCC stages. ROC curves and calibration curves showed that the nomogram was well calibrated and accurately distinguished high-risk and low-risk LADC patients. Weighted gene co-expression analysis showed significant correlation between prognostic risk signature genes and the turquoise module enriched with cell cycle genes. The high-risk LADC patients showed significantly higher PD-L1 levels, increased tumor mutational burden, and a lower proportion of CD8+ T cells in the tumor tissues and improved response to immune checkpoint blockade therapy. These findings show that this five-m6A regulatory gene signature is a prognostic biomarker in LADC and that immune checkpoint blockade is a potential therapeutic option for high-risk LADC patients.

DNA damage response and repair in osteosarcoma: Defects, regulation and therapeutic implications

Osteosarcoma (OS) is the most common primary bone malignancy in children and adolescents which has the survival rate of 20% in its advanced stages. Osteosarcomas are mostly resistance to our common treatments. DNA damage response (DDR) is a specialized multistep process containing abundant proteins which are necessary for the survival of any cell and organism. DDR machinery detects a diversity of DNA lesions and inhibits the cell cycle progression if these lesions are not repairable. DDR is involved in aging, age-related diseases, and cancer. In recent years, DDR inhibitors have gained the attention of researches due to their potentials in offering novel therapeutic targets and improving the response of many cancers to either chemo- or radio-therapy. In this regard, we tried to gather a great body of evidence about the role of DDR ingredients in osteosarcoma's initiation/progression, prognosis, and treatment.

The long noncoding RNA CRYBG3 induces aneuploidy by interfering with spindle assembly checkpoint via direct binding with Bub3

Aneuploidy is a hallmark of genomic instability that leads to tumor initiation, progression, and metastasis. CDC20, Bub1, and Bub3 form the mitosis checkpoint complex (MCC) that binds the anaphase-promoting complex or cyclosome (APC/C), a crucial factor of the spindle assembly checkpoint (SAC), to ensure the bi-directional attachment and proper segregation of all sister chromosomes. However, just how MCC is regulated to ensure normal mitosis during cellular division remains unclear. In the present study, we demonstrated that LNC CRYBG3, an ionizing radiation-inducible long noncoding RNA, directly binds with Bub3 and interrupts its interaction with CDC20 to result in aneuploidy. The 261-317 (S3) residual of the LNC CRYBG3 sequence is critical for its interaction with Bub3 protein. Overexpression of LNC CRYBG3 leads to aneuploidy and promotes tumorigenesis and metastasis of lung cancer cells, implying that LNC CRYBG3 is a novel oncogene. These findings provide a novel mechanistic basis for the pathogenesis of NSCLC after exposure to ionizing radiation as well as a potential target for the diagnosis, treatment, and prognosis of an often fatal disease.

Combinational treatment of gap junction enhancers and paclitaxel attenuates mammary tumor growth

A class of substituted quinolines (PQs) acts as a gap junction enhancer with the ability to increase the gap junctional intercellular communication in breast cancer cells. This study examined the effect of a combinational treatment of PQs and the antineoplastic drug paclitaxel in a xenograft animal model. Mice were implanted with estradiol-17ß (1.7 mg/pellet) before the injection of 1 × 10 T47D breast cancer cells subcutaneously into the inguinal region of mammary fat pad. Animals were treated intraperitoneally with DMSO (control), paclitaxel (10 mg/kg), PQ (25 mg/kg), or a combinational treatment of paclitaxel and PQ. There was no significant difference between the paclitaxel-treated animals and the control group after seven injections of treatment for 2 weeks. All mice treated with PQ had a significant decrease in mammary tumor growth. The combinational treatment of paclitaxel and PQ1 or PQ7 showed a reduction in tumor growth by 2.3- and 2.2-fold, respectively, compared to paclitaxel alone after seven treatments every 2 days. Molecular analysis indicated a significant increase of gap junction proteins and caspase signaling in PQ and paclitaxel-treated tissues compared to control. Furthermore, there is evidence of an upregulation of Cyclin D1 expression in paclitaxel-treated tumors compared to control, suggesting that the neoplastic cells were highly proliferative and nonresponsive to the paclitaxel alone. We have showed for the first time an increase in the efficacy of antineoplastic drugs via the enhancement of gap junctions with PQs, a specific class of gap junction enhancers.

Delivery of Protein Kinase A by CRISPRMAX and Its Effects on Breast Cancer Stem-Like Properties

Protein kinase A (PKA) activation has recently been reported to inhibit epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) ability, which is considered to be responsible for chemoresistance and tumor recurrence in patients. While current studies mainly focus on gene manipulation of the EMT process, the direct delivery of PKA enzymes to cancer cells has never been investigated. Here, we utilize the commercial Lipofectamine CRISPRMAX reagent to directly deliver PKAs to breast cancer cells and evaluate its effects on EMT regulation. We optimized the delivery parameters with fluorescent-labeled bovine serum albumin, and successfully delivered fluorescent PKAs through CRISPRMAX into breast cancer cells. Then, we evaluated the biological effects by immunofluorescence, flow cytometry, mammosphere assay, and chemoresistance assay. Our data showed the expression of EMT-related markers, α-smooth muscle actin and N-cadherin, was downregulated after CRISPRMAX-PKA treatment. Although the CD44+/CD24- population did not change considerably, the size of mammospheres significantly decreased. In paclitaxel and doxorubicin chemoresistance assays, we noticed PKA delivery significantly inhibited paclitaxel resistance rather than doxorubicin resistance. Taken together, these results suggest our direct enzyme delivery can be a potential strategy for inhibiting EMT/CSC-associated traits, providing a safer approach and having more clinical translational efficacy than gene manipulation. This strategy will also facilitate the direct testing of other target enzymes/proteins on their biological functions.

Paclitaxel Ameliorates Palmitate-Induced Injury in Mouse Podocytes

Background

Palmitate, a common saturated free fatty acid, is increased in patients with diabetic nephropathy (DN). Excessive palmitate in kidney is known to cause proteinuria and fibrosis. Several studies have demonstrated that paclitaxel has anti-fibrotic and anti-inflammatory effects on kidney disease. However, whether paclitaxel can relieve podocyte injury is unclear.

Material/Methods

Immortalized mouse podocytes were used as an in vitro system. Palmitate was used to induce podocyte injury. Podocytes were divided into 4 groups: bovine serum albumin, palmitate, palmitate+1 nM paclitaxel, and palmitate+5 nM paclitaxel. The effects of paclitaxel on palmitate-induced podocyte injury were analyzed by western blot and real-time PCR. Intracellular reactive oxygen species (ROS) generation and podocyte cytoskeletons were analyzed using CM-H2DCF-DA and phalloidin staining.

Results

Paclitaxel restored downregulated expression of nephrin and synaptopodin and upregulated VEGF expression after injury induced by palmitate. Remarkably, palmitate-induced actin cytoskeleton rearrangement in podocytes was repaired by paclitaxel. Four endoplasmic reticulum stress markers, ATF-6α, Bip, CHOP, and spliced xBP1, were significantly increased in palmitate-treated podocytes compared with control podocytes. Such increases were decreased by paclitaxel treatment. Palmitate-induced ROS generation was ameliorated by paclitaxel. Elevated Nox4 expression was also improved by paclitaxel. Paclitaxel alleviated the expression levels of the antioxidant molecules, Nrf-2, HO-1, SOD-1, and SOD-2. The paclitaxel effects were accompanied by inhibition of the inflammatory cytokines, MCP-1, TNF-α, TNF-R2, and TLR4, as well as attenuation of the apoptosis markers, Bax, Bcl-2, and Caspase-3. Furthermore, paclitaxel suppressed the palmitate-induced fibrosis molecules, fibronectin and TGF-β1.

Conclusions

This study suggests that paclitaxel could be a therapeutic agent for treating palmitate-induced podocyte injury in DN.

Identification of key genes and biological pathways in lung adenocarcinoma via bioinformatics analysis

Lung adenocarcinoma (LUAD) accounts for the majority of cancer-related deaths worldwide. Our study identified key LUAD genes and their potential mechanism via bioinformatics analysis of public datasets. GSE10799, GSE40791, and GSE27262 microarray datasets were retrieved from the Gene Expression Omnibus (GEO) database. The RobustRankAggreg package was used to perform a meta-analysis, and 50 upregulated genes and 87 downregulated genes overlapped in three datasets. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the Database for Annotation, Visualization, and Integrated Discovery (DAVID). Furthermore, protein-protein interaction (PPI) networks of the differentially expressed genes (DEGs) were built by the Search Tool for the Retrieval of Interacting Genes (STRING) and 22 core genes were identified by Molecular Complex Detection (MCODE) and visualized with Cytoscape. Subsequently, these core genes were analyzed by the Kaplan-Meier Plotter and Gene Expression Profiling Interactive Analysis (GEPIA). The results showed that all 22 genes were significantly associated with reduced survival rates. For GEPIA, the expression of only one gene was not significantly different between LUAD tissues and normal tissues. A KEGG pathway enrichment reanalysis of the 21 genes identified five key genes (CCNB1, BUB1B, CDC20, TTK, and MAD2L1) in the cell cycle pathway. Finally, the Comparative Toxicogenomics Database (CTD) website was used to explore the relationship between these key genes and certain drugs. Based on the bioinformatics analysis, five key genes were identified in LUAD, and drugs closely associated these genes can provide clues for the treatment and prognosis of LUAD.

The ubiquitous transcriptional protein ZNF143 activates a diversity of genes while assisting to organize chromatin structure

Zinc Finger Protein 143 (ZNF143) is a pervasive C2H2 zinc-finger transcriptional activator protein regulating the efficiency of eukaryotic promoter regions. ZNF143 is able to activate transcription at both protein coding genes and small RNA genes transcribed by either RNA polymerase II or RNA polymerase III. Target genes regulated by ZNF143 are involved in an array of different cellular processes including both cancer and development. Although a key player in regulating eukaryotic genes, the molecular mechanism by with ZNF143 binds and activates genes transcribed by two different polymerases is still relatively unknown. In addition to its role as a transcriptional regulator, recent genomics experiments have implicated ZNF143 as a potential co-factor involved in chromatin looping and establishing higher order structure within the genome. This review focuses primarily on possible activation mechanisms of promoters by ZNF143, with less emphasis on the role of ZNF143 in cancer and development, and its function in establishing higher order chromatin contacts within the genome.

Expression of miR-34a is a sensitive biomarker for exposure to genotoxic agents in human lymphoblastoid TK6 cells

miR-34a has been identified as a tumor suppressor microRNA (miRNA) involved in the P53 network. Its expression levels correlate to carcinogenesis, which are generally lower in tumor tissue and higher in response to DNA damage. In this study, the response of miR-34a from exposure to genotoxic agents in human lymphoblastoid TK6 cells was evaluated to assess whether the expression of this miRNA could be used as an early indicator for genotoxic damage in mammalian cells. TK6 cells were treated with seven genotoxic agents with different mode-of-actions (cisplatin, N-ethyl-N-nitrosourea, etoposide, mitomycin C, methyl methanesulphonate, taxol, and X-ray radiation) and a non-genetic toxin (usnic acid) at different concentrations for four hours (except for X-rays) and the expression levels of miR-34a were measured 24 h after the beginning of the treatments. The expression levels of miR-34a were significantly increased by these genetic toxins in a dose-dependent manner, while no significant change in miRNA expression was found in the usnic acid-treated cells. These results suggest that miR-34a can respond to genotoxic insults sensitively; thus, miR-34a expression has the potential to be used to evaluate genotoxicity of agents.

Exploiting aneuploidy-imposed stresses and coping mechanisms to battle cancer

Aneuploidy, an irregular number of chromosomes in cells, is a hallmark feature of cancer. Aneuploidy results from chromosomal instability (CIN) and occurs in almost 90% of all tumours. While many cancers display an ongoing CIN phenotype, cells can also be aneuploid without displaying CIN. CIN drives tumour evolution as ongoing chromosomal missegregation will yield a progeny of cells with variable aneuploid karyotypes. The resulting aneuploidy is initially toxic to cells because it leads to proteotoxic and metabolic stress, cell cycle arrest, cell death, immune cell activation and further genomic instability. In order to overcome these aneuploidy-imposed stresses and adopt a malignant fate, aneuploid cancer cells must develop aneuploidy-tolerating mechanisms to cope with CIN. Aneuploidy-coping mechanisms can thus be considered as promising therapeutic targets. However, before such therapies can make it into the clinic, we first need to better understand the molecular mechanisms that are activated upon aneuploidization and the coping mechanisms that are selected for in aneuploid cancer cells. In this review, we discuss the key biological responses to aneuploidization, some of the recently uncovered aneuploidy-coping mechanisms and some strategies to exploit these in cancer therapy.

A novel taxane, difluorovinyl-ortataxel, effectively overcomes paclitaxel-resistance in breast cancer cells

Paclitaxel (PTX) is widely used to treat breast and ovarian cancers, but innate and acquired resistance often compromises its applications. The objective of this study was to screen new-generation taxanes for their efficiency against both PTX-sensitive and PTX-resistant breast cancer cells. From twelve compounds, difluorovinyl-ortataxel (DFV-OTX) displayed potent cytotoxic activities against both PTX-sensitive and PTX-resistant breast cancer cells. Moreover, DFV-OTX effectively induced tubulin/microtubule polymerization and G2/M phase arrest, leading to apoptosis in both PTX-sensitive and PTX-resistant cancer cells. Molecular docking analysis showed that DFV-OTX possesses unique hydrogen-bonding and van der Waals interactions with β-tubulin. LC-MS/MS analysis also demonstrated that the intracellular drug amount of DFV-OTX was lower than that of PTX, which would be critical to overcome PTX-resistance. Furthermore, DFV-OTX exhibited clear efficacy in the MCF-7R and MDA-MB-231R tumor xenografts in mouse models. Taken together, our results demonstrate that the novel taxane, DFV-OTX, can effectively overcome PTX-resistance in MDA-MB-231R cells, wherein the drug resistance was attributed to ABCB1/ABCG2 upregulation and a distinct mode of action in MCF-7R cells. Our results strongly indicate that DFV-OTX is a promising chemotherapeutic agent for the treatment of PTX-resistant cancers.

Anti-PSMA monoclonal antibody increases the toxicity of paclitaxel carried by carbon nanotubes

Multiple-wall carbon nanotubes (CNTs) were functionalized with polyethyleneimine in order to incorporate paclitaxel (PTX), the first line chemotherapeutic agent for prostate cancer. These particles were then covered with antibodies for the prostate-specific membrane antigen (PSMA), to address them to prostate cancer cells. LNCaP prostate cancer cells (PSMA⁺), HCT-116 and CaCo-2 colon cancer cells (PSMA^-), as well as human peripheral monocytes and lymphocytes (PSMA^-), were in vitro exposed to fluorescent CNT composites. The interaction/adherence of those composites to target cells was analyzed by fluorescence microscopy and flow cytometry, showing a diffuse interaction of CNTs and CNT-PTX with all cell types. Analysis of cytotoxicity revealed that both prostate (PSMA⁺) and colorectal cancer cells (PSMA^-) were more susceptible to PTX complexed with CNTs than to pure PTX or CNTs alone, while the incorporation of anti-PSMA (CNT-PTX-PSMA) improved the toxicity on LNCaP cells but not on PSMA^- targets. No toxicity was observed in human monocytes and lymphocytes but composites induced phenotypical changes in monocytes. Our results demonstrate the feasibility of using anti-PSMA antibody to address drug-loaded CNT to cancer cells as a strategy for improving the effectiveness of antineoplastic agents.

Protein Complex NDC80: Properties, Functions, and Possible Role in Pathophysiology of Cell Division

Mitotic division maintains genetic identity of any multicellular organism throughout an entire lifetime. Each time a parent cell divides, chromosomes are equally distributed between the daughter cells due to the action of mitotic spindle. Mitotic spindle is formed by the microtubules that represent dynamic polymers of tubulin protein. Spindle microtubules are attached end-on to kinetochores - large multi-protein complexes on chromosomes. This review focuses on the four-subunit NDC80 complex, one of the most important kinetochore elements that plays a major role in the attachment of assembling/disassembling microtubule ends to the chromosomes. Here, we summarize published data on the structure, properties, and regulation of the NDC80 complex and discuss possible relationship between changes in the expression of genes coding for the NDC80 complex components, mitotic disorders, and oncogenesis with special emphasis on the diagnostic and therapeutic potential of NDC80.

CSAG1 maintains the integrity of the mitotic centrosome in cells with defective p53

Centrosomes focus microtubules to promote mitotic spindle bipolarity, a critical requirement for balanced chromosome segregation. Comprehensive understanding of centrosome function and regulation requires a complete inventory of components. While many centrosome components have been identified, others yet remain undiscovered. We have used a bioinformatics approach, based on 'guilt by association' expression to identify novel mitotic components among the large group of predicted human proteins that have yet to be functionally characterized. Here, we identify chondrosarcoma-associated gene 1 protein (CSAG1) in maintaining centrosome integrity during mitosis. Depletion of CSAG1 disrupts centrosomes and leads to multipolar spindles, particularly in cells with compromised p53 function. Thus, CSAG1 may reflect a class of 'mitotic addiction' genes, whose expression is more essential in transformed cells.

Absence of the TRIP13 c.1060C>T Mutation in Wilms Tumor Patients From Pakistan

BACKGROUND AND AIM

Wilms tumor (WT) is the most common childhood malignant renal tumor. Germline mutations in several WT predisposition genes have been identified. However, the fundamental cause of most WT patients remains unexplained. Recently, a founder mutation, c.1060C>T (p. Arg254X) in a mitotic spindle checkpoint gene, TRIP13, was reported in 5 unrelated children with WT from the United Kingdom, of Pakistani descent from Azad Kashmir region. This observation suggests other children with WT in Pakistan may also harbor this mutation. We conducted the first study to assess the contribution of TRIP13 c.1060C>T mutation to WT in Pakistan.

MATERIALS AND METHODS

Constitutional genomic DNA from 68 Pakistani individuals including unrelated WT cases (n=26) and one (n=10) or both (n=32) of their parent(s) were screened for the TRIP13 c.1060C>T mutation using DNA sequence analysis. We also included positive controls in the analyses.

RESULTS

The median age of WT diagnosis was 3.0 years (range, 0.75 to 10). The TRIP13 c.1060C>T mutation was not found in any WT patient (n=26) or their parents (n=42). Twenty-four patients (92.4%) presented with unilateral tumor and 2 patients (7.7%) were diagnosed with synchronous bilateral WT. Thirteen patients (50%) reported parental consanguinity. Thirteen patients (50.0%) belonged to the Punjabi ethnicity and 1 patient (3.8%) had a Kashmiri background. Four patients (16.7%) reported a family history of WT or other malignancies. The predominant histologic subtype was stromal (46.2%). The majority of patients presented with >5 cm of tumor size (81%). None of the patients had a personal or family history of congenital anomalies, or associated genetic syndromes.

CONCLUSIONS

Our findings suggest that TRIP13 c.1060C>T mutation may be infrequent in Pakistani WT cases. Further evaluation of this mutation in a large number of WT patients of Kashmiri heritage and various ethnic backgrounds from Pakistan is warranted.