Cyclin D1 degradation is sufficient to induce G1 cell cycle arrest despite constitutive expression of cyclin E2 in ovarian cancer cells

Enhancing Therapeutic Response and Overcoming Resistance to Checkpoint Inhibitors in Ovarian Cancer through Cell Cycle Regulation

Tumor cells invade normal surrounding tissues through continuous division. In this study, we hypothesized that cell cycle regulation changes the immune efficacy of ovarian cancer. To investigate this hypothesis, a Förster resonance energy transfer (FRET) sensor was constructed to characterize the cell activity in real time. Cell shrinkage caused by apoptosis induces the aggregation of proteins on the cell membrane, leading to variations in the fluorescence lifetime of FRET sensors. Moreover, we tracked cell activity across various cycles following co-culture with an immune checkpoint inhibitor. Consequently, we assessed how cell cycle regulation influences immunotherapy in a tumor mouse model. This approach, which involves inhibiting typical cell cycle processes, markedly enhances the effectiveness of immunotherapy. Our findings suggest that modulating the cycle progression of cancer cells may represent a promising approach to enhance the immune response of ovarian cancer cells and the efficacy of immunotherapy based on immune checkpoint inhibitors.

α-synuclein regulates Cyclin D1 to promote abnormal initiation of the cell cycle and induce apoptosis in dopamine neurons

The etiology of Parkinson's disease (PD) is characterized by the death of dopamine neurons in the substantia nigra pars compacta, while misfolding and abnormal aggregation of α-synuclein (α-syn) are core pathological features. Previous studies have suggested that damage to dopamine neurons may be related to cell cycle dysregulation, but the specific mechanisms remain unclear. In this study, a PD mouse model was induced by stereotactic injection of α-syn into the nucleus, and treated with the cell cycle inhibitor, roscovitine (Rosc). The results demonstrated that Rosc improved behavioral disorders caused by α-syn, increased TH protein expression, inhibited α-syn and p-α-syn protein expression, and reduced the expression levels of G1/S phase cell cycle genes Cyclin D1, Cyclin E, CDK2, CDK4, E2F and pRB. Additionally, Rosc decreased Bax and Caspase-3 expression caused by α-syn, while increasing Bcl-2 protein expression. Meanwhile, we observed that α-syn can influence neuronal cell autophagy by decreasing the expression level of Beclin 1 and increasing the expression level of P62. However, Rosc can improve this phenomenon. In a cell model induced by α-syn in dopamine neuron injury cells, knockdown of Cyclin D1 led to similar results as those observed in animal experiments: Knocking down Cyclin D1 improved the abnormal initiation of the cell cycle caused by α-syn and regulated cellular autophagy, resulting in a reduction of apoptosis in dopamine neurons. In summary, exogenous α-syn can lead to the accumulation of α-syn and phosphorylated α-syn in dopamine neurons, increase key factors of the G1/S phase cell cycle such as Cyclin D1, and regulate downstream related indicators, causing the cell cycle to restart and leading to apoptosis of dopamine neurons. This exacerbates PD symptoms. However, knockdown of Cyclin D1 inhibits the progression of the cell cycle and can reverse this situation. These findings suggest that a Cyclin D inhibitor may be a novel therapeutic target for treating PD.

Manipulation of metabolic responses enhances SHetA2 efficacy without toxicity in cervical cancer cell lines and xenografts

OBJECTIVE

The high frequency of cervical cancer recurrence after primary therapy necessitates alternative treatments. High-risk human papillomavirus (HR-HPV) causes cervical cancer and it's continued presence supports elevated metabolism, proliferation and survival of cancer cells. The low-to-no toxicity new investigational drug, SHetA2, counteracts high-risk human papillomavirus (HR-HPV) effects on cell proliferation and survival in cervical cancer cells and xenograft tumors by disrupting heat shock protein 70 chaperone protection of oncogenic proteins. Our objective was to study the involvement of metabolism in SHetA2 effects on cervical cancer cells and tumors.

METHODS

SHetA2-mediated proteomic and metabolic effects were measured in HR-HPV-positive CaSKi and SiHa and HR-HPV-negative C-33 A cervical cancer cell lines. Combined treatment with 2-deoxyglucose (2-DG) was evaluated in cell culture and SiHa xenografts.

RESULTS

SHetA2 inhibited oxidative phosphorylation (OxPhos) and altered levels of proteins involved in metabolism, protein synthesis, and DNA replication and repair. Cervical cancer cells responded by elevating glycolysis. Inhibition of the glycolytic responses using galactose media or 2-DG increased SHetA2 sensitivity of two HR-HPV-positive, but not an HR-HPV-negative cervical cancer cell line. Interaction of 2-DG and SHetA2 was synergistic in HR-HPV positive cell lines in association with augmentation of SHetA2 ATP reduction, but not SHetA2 DNA damage induction. These results were verified in a SiHa xenograft tumor model without evidence of toxicity.

CONCLUSIONS

Compensatory glycolysis counteracts OxPhos inhibition in SHetA2-treated HR-HPV-positive cervical cancer cell lines. Prevention of compensatory glycolysis with 2-DG or another glycolysis inhibitor has the potential to improve SHetA2 therapy without toxicity.

Pharmacodynamics of Cyclin D1 Degradation in Ovarian Cancer Xenografts with Repeated Oral SHetA2 Dosing

SHetA2 is a promising, orally active small molecule with anticancer properties that target heat shock proteins. In this study, we aimed to investigate the pharmacodynamic (PD) effects of SHetA2 using preclinical in vitro and in vivo models of ovarian cancer and establish a physiologically based pharmacokinetic (PBPK)/PD model to describe their relationships with SHetA2 concentrations in mice. We found that daily oral administration of 60 mg/kg SHetA2 for 7 days resulted in consistent plasma PK and tissue distribution, achieving tumor drug concentrations required for growth inhibition in ovarian cancer cell lines. SHetA2 effectively induced cyclin D1 degradation in cancer cells in a dose-dependent manner, with up to 70% reduction observed and an IC50 of 4~5 µM. We identified cyclin D1 as a potential PD marker for SHetA2, based on a well-correlated time profile with SHetA2 PK. Additionally, we examined circulating levels of ccK18 as a non-invasive PD marker for SHetA2-induced apoptotic activity and found it unsuitable due to high variability. Using a PBPK/PD model, we depicted SHetA2 levels and their promoting effects on cyclin D1 degradation in tumors following multiple oral doses. The model suggested that twice-daily dosing regimens would be effective for sustained reduction in cyclin D1 protein. Our study provides valuable insights into the PK/PD of SHetA2, facilitating future clinical trial designs and dosing schedules.

Synergistic anti-proliferative and apoptotic effect of NVP-BEZ235 and curcumin on human SH-SY5Y neuroblastoma cells

Neuroblastoma, a tumor of the sympathetic nervous system, is one of the most common tumors found in children. Most patients develop resistance to therapy and show poor prognosis, thus there is a need of novel therapeutic agents for the treatment of neuroblastoma. NVP-BEZ235 is a dual Phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) kinase inhibitor that induces apoptosis and suppresses the growth of cancer. Curcumin acts as an anticancer agent in certain cancers. This study investigated the synergetic effect of NVP-BEZ235 and curcumin against neuroblastoma SH-SY5Y cell line. In the current study, the synergic effect of NVP-BEZ235 and curcumin in SH-SY5Y was examined in terms of the cell growth by cell viability and colony forming assay, cell cycle and apoptotic cell death by flow cytometry and mRNA expression levels by quantitative Real Time Polymerase Chain Reaction (qRT-PCR). Curcumin, NVP-BEZ235 or a combination of both, showed cytotoxicity in a dose and time dependent manner in SH-SY5Y cells. 10 µM curcumin and 200 nM NVP-BEZ235 were chosen as combination therapy, as the combination index showed synergism. Colony forming assay showed decrease in cell growth in combination group. The cell cycle distribution for combination group demonstrated a decrease in G0/G1 phase at 48 h. Annexin V showed an anticancer effect in combination group when compared to control group. Moreover, qRT-PCR results showed a significant increase in caspase 3, caspase 7, Bax and p53 genes, while a decrease in Bcl-2 gene expression levels. These findings suggest that combination therapy of NVP-BEZ235 and curcumin may be a promising therapeutic candidate for treatment of neuroblastoma.

Nonivamide inhibits proliferation of human corneal epithelial cells by inducing cell cycle arrest and oxidative stress

Nonivamide, an agonist of transient receptor potential vanilloid type 1 (TRPV1), is widely used as a riot control agent, police incapacitant spray and pesticide. Although generally considered non-fatal, eye discomfort and even ocular injuries caused by such products are common. Little research has been conducted on the effects of nonivamide on corneal epithelial cells. Cell viability, impedance, flow cytometry, western blotting, and real-time fluorescence analyses were performed to investigate the effects of nonivamide on human corneal epithelial cells (HCE-T cells). We found that nonivamide impaired proliferation at subtoxic doses (100 μM and 200 μM) in HCE-T cells. Next, we described the mechanisms of action of nonivamide. Nonivamide caused cell cycle arrest by increasing p21 and decreasing cyclin D1. TRPV1 was activated by nonivamide, leading to an influx of Ca2+. Enhanced Ca2+ influx partially contributed to oxidative stress. Mitochondrial membrane potential (MMP) also decreased. All combined stress resulted in the inhibition of cell proliferation in HCE-T cells. In summary, nonivamide inhibited the proliferation of HCE-T cells at sub-toxic doses by inducing cell cycle arrest and oxidative stress. Our data demonstrate the corneal toxicity of nonivamide and explain the mechanisms underlying nonivamide-induced corneal injury.

Combined doxorubicin and arctigenin treatment induce cell cycle arrest-associated cell death by promoting doxorubicin uptake in doxorubicin-resistant breast cancer cells

Chemotherapy failure is often caused by drug resistance, for which no effective treatment strategy has been established. Many studies have been undertaken with the aim of overcoming drug resistance using natural products. Arctigenin (ATG), a natural product, has been investigated for its anti-cancer effects in HER2-overexpressing, ER-positive, and triple-negative breast cancer cells. We investigated the efficacy of ATG against self-established doxorubicin (DOX)-resistant breast cancer cells (MCF-DR and MDA-DR cells) derived from MCF-7 and MDA-MB-231 cells, respectively. ATG was found to increase DOX intracellular levels by downregulating multidrug Resistance 1 (MDR1) mRNA expression in DOX-resistant cells. In addition, combined treatment with DOX and ATG (DOX/ATG) reduced the viability of and colony formation by DOX-resistant cells. DOX/ATG also significantly induced G2/M cell cycle arrest by suppressing the Cyclin D1/CDK4/RB pathways and suppressed the expressions of MDR1 and Cyclin D1 by inhibiting the Mitogen-activated protein kinase (MAPK)/Activating protein-1 (AP-1) signaling pathways. Furthermore, DOX/ATG induced DNA damage and attenuated the expressions of RAD51 and Ku80. However, PARP1 (Poly [ADP-ribose] polymerase1) cleavage and AIF (Apoptosis-inducing factor) induced apoptosis did not occur despite DNA damage-induced cell death. Rather, flow cytometry showed that DOX/ATG caused necrosis. In summary, DOX/ATG increased intracellular DOX levels by inhibiting MDR1 and inducing G2/M arrest by inhibiting the Cyclin D1/CDK4/RB pathways and causing necrosis by damaging DNA. Our results suggest that ATG might be used as an adjuvant to enhance the efficacy of DOX in DOX-resistant breast cancer.

Epithelial tissue confinement inhibits cell growth and leads to volume-reducing divisions

Cell proliferation is a central process in tissue development, homeostasis, and disease, yet how proliferation is regulated in the tissue context remains poorly understood. Here, we introduce a quantitative framework to elucidate how tissue growth dynamics regulate cell proliferation. Using MDCK epithelial monolayers, we show that a limiting rate of tissue expansion creates confinement that suppresses cell growth; however, this confinement does not directly affect the cell cycle. This leads to uncoupling between rates of cell growth and division in epithelia and, thereby, reduces cell volume. Division becomes arrested at a minimal cell volume, which is consistent across diverse epithelia in vivo. Here, the nucleus approaches the minimum volume capable of packaging the genome. Loss of cyclin D1-dependent cell-volume regulation results in an abnormally high nuclear-to-cytoplasmic volume ratio and DNA damage. Overall, we demonstrate how epithelial proliferation is regulated by the interplay between tissue confinement and cell-volume regulation.

Urolithin B loaded in cerium oxide nanoparticles enhances the anti-glioblastoma effects of free urolithin B in vitro

Glioblastoma multiforme (GBM) is the most aggressive kind of malignant primary brain tumor in humans. Given the limitation of Conventional therapeutic strategy, the development of nanotechnology and natural product therapy seems to be an effective method enhancing the prognosis of GBM patients. In this research, cell viability, mRNA expressions of various apoptosis-related genes apoptosis, and generation of reactive oxygen species (ROS) in human U-87 malignant GBM cell line (U87) treated with Urolithin B (UB) and CeO₂-UB. Unlike CeO₂-NPs, both UB and CeO₂-UB caused a dose-dependent decrease in the viability of U87 cells. The half-maximal inhibitory concentration values of UB and CeO₂-UB were 315 and 250 μM after 24 h, respectively. Moreover, CeO₂-UB exerted significantly higher effects on U87 viability, P53 expression, and ROS generation. Furthermore, UB and CeO2-UB increased the accumulation of U87 cells in the SUB-G1 population, decreased the expression of cyclin D1, and increased the Bax/Bcl2 ratio expression. Collectively, these data indicate that CeO₂-UB exhibited more substantial anti-GBM effects than UB. Although further in vivo investigations are needed, these results proposed that CeO₂-NPs could be utilized as a potential novel anti-GBM agent after further studies.

Do Aging and Parity Affect VEGF-A/VEGFR Content and Signaling in the Ovary?-A Mouse Model Study

In this study, the effects of aging and parity on VEGF-A/VEGFR protein content and signaling in the mice ovaries were determined. The research group consisted of nulliparous (virgins, V) and multiparous (M) mice during late-reproductive (L, 9-12 months) and post-reproductive (P, 15-18 months) stages. Whilst ovarian VEGFR1 and VEGFR2 remained unchanged in all the experimental groups (LM, LV, PM, PV), protein content of VEGF-A and phosphorylated VEGFR2 significantly decreased only in PM ovaries. VEGF-A/VEGFR2-dependent activation of ERK1/2, p38, as well as protein content of cyclin D1, cyclin E1, and Cdc25A were then assessed. In ovaries of LV and LM, all of these downstream effectors were maintained at a comparable low/undetectable level. Conversely, the decrease recorded in PM ovaries did not occur in the PV group, in which the significant increase of kinases and cyclins, as well phosphorylation levels mirrored the trend of the pro-angiogenic markers. Altogether, the present results demonstrated that, in mice, ovarian VEGF-A/VEGFR2 protein content and downstream signaling can be modulated in an age- and parity-dependent manner. Moreover, the lowest levels of pro-angiogenic and cell cycle progression markers detected in PM mouse ovaries sustains the hypothesis that parity could exert a protective role by downregulating the protein content of key mediators of pathological angiogenesis.

Comparative oncology reveals DNMT3B as a molecular vulnerability in undifferentiated pleomorphic sarcoma

PURPOSE

Undifferentiated pleomorphic sarcoma (UPS), an aggressive subtype of soft-tissue sarcoma (STS), is exceedingly rare in humans and lacks effective, well-tolerated therapies. In contrast, STS are relatively common in canine companion animals. Thus, incorporation of veterinary patients into studies of UPS offers an exciting opportunity to develop novel therapeutic strategies for this rare human disease. Genome-wide studies have demonstrated that UPS is characterized by aberrant patterns of DNA methylation. However, the mechanisms and impact of this epigenetic modification on UPS biology and clinical behavior are poorly understood.

METHODS

DNA methylation in mammalian cells is catalyzed by the canonical DNA methyltransferases DNMT1, DNMT3A and DNMT3B. Therefore, we leveraged cell lines and tissue specimens from human and canine patients, together with an orthotopic murine model, to probe the functional and clinical significance of DNMTs in UPS.

RESULTS

We found that the DNA methyltransferase DNMT3B is overexpressed in UPS relative to normal mesenchymal tissues and is associated with a poor prognosis. Consistent with these findings, genetic DNMT3B depletion strongly inhibited UPS cell proliferation and tumor progression. However, existing hypomethylating agents, including the clinically approved drug 5-aza-2'-deoxycytidine (DAC) and the DNMT3B-inhibiting tool compound nanaomycin A, were ineffective in UPS due to cellular uptake and toxicity issues.

CONCLUSIONS

DNMT3B represents a promising molecular susceptibility in UPS, but further development of DNMT3B-targeting strategies for these patients is required.

Therapeutic Potential of Plant Oxylipins

For immobile plants, the main means of protection against adverse environmental factors is the biosynthesis of various secondary (specialized) metabolites. The extreme diversity and high biological activity of these metabolites determine the researchers' interest in plants as a source of therapeutic agents. Oxylipins, oxygenated derivatives of fatty acids, are particularly promising in this regard. Plant oxylipins, which are characterized by a diversity of chemical structures, can exert protective and therapeutic properties in animal cells. While the therapeutic potential of some classes of plant oxylipins, such as jasmonates and acetylenic oxylipins, has been analyzed thoroughly, other oxylipins are barely studied in this regard. Here, we present a comprehensive overview of the therapeutic potential of all major classes of plant oxylipins, including derivatives of acetylenic fatty acids, jasmonates, six- and nine-carbon aldehydes, oxy-, epoxy-, and hydroxy-derivatives of fatty acids, as well as spontaneously formed phytoprostanes and phytofurans. The presented analysis will provide an impetus for further research investigating the beneficial properties of these secondary metabolites and bringing them closer to practical applications.

Identification of a novel pyridine derivative with inhibitory activity against ovarian cancer progression in vivo and in vitro

Ovarian cancer is the second leading cause of death of female gynecological malignant tumor patients worldwide. Although surgery and chemotherapy have achieved dramatic achievement, the mortality remains high, resulting in the demand for new specific drug discovery. Disrupting ovarian cancer growth via histone deacetylase (HDAC) inhibition is a strategy for cancer therapy or prevention. In this work, we synthesized a novel pyridine derivative named compound H42 and investigated its anti-cancer activity in vivo and in vitro. We found that compound H42 inhibited ovarian cancer cell proliferation with IC50 values of 0.87 μM (SKOV3) and 5.4 μM (A2780). Further studies confirmed that compound H42 induced apoptosis, intracellular ROS production, and DNA damage. Moreover, compound H42 downregulated the expression of histone deacetylase 6 (HDAC6) with a distinct increase in the acetylation of α-tubulin and heat shock protein 90 (HSP90), followed by the degradation of cyclin D1, resulting in cell cycle arrest at the G0/G1 phase. Importantly, ectopic expression of HDAC6 induced deacetylation of HSP90 and α-tubulin, while HDAC6 knockdown upregulated the acetylation of HSP90 and α-tubulin. However, in the nude xenograft mouse study, compound H42 treatment can inhibit ovarian cancer growth without obvious toxicity. These findings indicated that compound H42 inhibited ovarian cancer cell proliferation through inducing cell cycle arrest at the G0/G1 phase via regulating HDAC6-mediated acetylation, suggesting compound H42 could serve as a lead compound for further development of ovarian cancer therapeutic agents.

Cyclin D3 restricts SARS-CoV-2 envelope incorporation into virions and interferes with viral spread

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents a great threat to human health. The interplay between the virus and host plays a crucial role in successful virus replication and transmission. Understanding host-virus interactions are essential for the development of new COVID-19 treatment strategies. Here, we show that SARS-CoV-2 infection triggers redistribution of cyclin D1 and cyclin D3 from the nucleus to the cytoplasm, followed by proteasomal degradation. No changes to other cyclins or cyclin-dependent kinases were observed. Further, cyclin D depletion was independent of SARS-CoV-2-mediated cell cycle arrest in the early S phase or S/G2/M phase. Cyclin D3 knockdown by small-interfering RNA specifically enhanced progeny virus titres in supernatants. Finally, cyclin D3 co-immunoprecipitated with SARS-CoV-2 envelope (E) and membrane (M) proteins. We propose that cyclin D3 impairs the efficient incorporation of envelope protein into virions during assembly and is depleted during SARS-CoV-2 infection to restore efficient assembly and release of newly produced virions.

Regulation of CyR61 expression and release by 3-mercaptopyruvate sulfurtransferase in colon cancer cells

Cysteine-rich angiogenic inducer 61 (CYR61, also termed CCN family member 1 or CCN1), is a matricellular protein encoded by the CYR61 gene. This protein has been implicated in the regulation of various cancer-associated processes including tumor growth, angiogenesis, tumor cell adhesion, migration, and invasion as well as the regulation of anticancer drug resistance. Hydrogen sulfide (H₂S) is a gaseous endogenous biological mediator, involved in the regulation of cellular bioenergetics, angiogenesis, invasion, and chemotherapeutic resistance in several types of cancer. H₂S is produced by three enzymes: cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST). The current studies were set up to investigate if CBS or 3-MST regulates CyR61 in colon cancer cells in the context of the regulation of proliferation, migration, and survival. The study mainly utilized HCT116 cells, in which two of the principal H₂S-producing enzymes, CBS and 3-MST, are highly expressed. The H₂S donor GYY4137 and the polysulfide donor Na₂S₃ activated the CyR61 promoter in a concentration-dependent fashion. Aminooxyacetic acid (AOAA), a pharmacological inhibitor of CBS as well as HMPSNE: 2-[(4-hydroxy-6- methylpyrimidin-2-yl)sulfanyl]-1-(naphthalen-1-yl)ethan-1-one, a pharmacological inhibitor of 3-MST inhibited CyR61 mRNA expression. This effect was more pronounced in response to HMPSNE than to AOAA and occurred through the modulation of S1PR via ATF1 and CREB. CyR61 was found to play an active, but relatively minor role in maintaining colon cell proliferation. HMPSNE markedly suppressed the secretion/release of CyR61 from the colon cancer cells. Moreover, HMPSNE promoted colon cancer cell apoptosis; endogenously produced CyR61 was found to counteract this effect, at least in part via RhoA activation. Taken together, we conclude that the upregulation of 3-MST in cancer cells exerts cytoprotective effects and confers the cancer cells a more aggressive phenotype - at least in part via the modulation of CyR61 expression and release.

Why is Mortalin a Potential Therapeutic Target for Cancer?

Cancer is one of the leading causes of death worldwide, accounting for nearly 10 million deaths in 2020. Therefore, cancer therapy is a priority research field to explore the biology of the disease and identify novel targets for the development of better treatment strategies. Mortalin is a member of the heat shock 70 kDa protein family. It is enriched in several types of cancer and contributes to carcinogenesis in various ways, including inactivation of the tumor suppressor p53, deregulation of apoptosis, induction of epithelial–mesenchymal transition, and enhancement of cancer stemness. It has been studied extensively as a therapeutic target for cancer treatment, and several types of anti-mortalin molecules have been discovered that effectively suppress the tumor cell growth. In this review, we 1) provide a comprehensive sketch of the role of mortalin in tumor biology; 2) discuss various anti-mortalin molecules, including natural compounds, synthetic small molecules, peptides, antibodies, and nucleic acids, that have shown potential for cancer treatment in laboratory studies; and 3) provide future perspectives in cancer treatment.

SHetA2 Attack on Mortalin and Colleagues in Cancer Therapy and Prevention

Heat Shock Proteins of the 70-kDa family (HSP70s) do not cause cancer by themselves, but instead protect cells as they transform into cancer. These molecular chaperones bind numerous client proteins and utilize ATP hydrolysis to facilitate proper protein folding, formation of functional complexes and cellular localizations, or degradation of irreparably damaged proteins. Their transient upregulation by stressful situations avoids induction of programmed cell death. Continued upregulation of the mortalin, heat shock cognate (hsc70) and glucose regulated protein 78 (Grp78) support cancer development and progression by supporting pro-proliferative and metabolic functions and repressing pro-death functions of oncoproteins and tumor suppressor proteins. This review describes the discovery and development of a lead anti-cancer compound, sulfur heteroarotinoid A2 (SHetA2, NSC726189), which was originally developed to bind retinoic acid receptors, but was subsequently found to work independently of these receptors. The discovery and validation of mortalin, hsc70 and Grp78 as SHetA2 target proteins is summarized. The documented and hypothesized roles of these HSP70 proteins and their clients in the mechanism of SHetA2 inhibition of cancer without toxicity are discussed. Use of this mechanistic data to evaluate drug action in a cancer clinical trial and develop synergistic drug combinations is explained. Knowledge needed to optimize SHetA2 analogs for use in cancer therapy and prevention is proposed as future directions.

Leaf extract of Osbeckia octandra induces apoptosis in oral squamous cell carcinoma cells

Background

Osbeckia octandra is a plant endemic to Sri Lanka and is used in ethnomedicine for treating various diseases. However, the anti-cancer properties of O. octandra are yet to be fully investigated. In the present study, we evaluated the anti-cancer effects of O. octandra on oral cancer cells.

Methods

Human oral cancer cell lines (HSC2, YD10B, YD38, YD9, and YD32) were used in this study. BrdU incorporation, cell cycle and annexin-V/PI staining were all evaluated using flow cytometry to determine the extent to which O. octandra leaf extract inhibits cell proliferation and induces apoptosis. Cell viability and reactive oxygen species (ROS) were also measured in order to investigate the anti-cancer effects of O. octandra extracts. Western blotting was performed to detect cell cycle related protein such as cyclin d1 and cdk4, and to detect apoptosis-related proteins such as Bcl-2, Bcl-X_L, Bax, Caspase-9, Cleaved caspase-3, Fas, Caspase-8, and Bid.

Results

Leaf extract of O. octandra reduced oral squamous cell carcinoma (OSCC) cell viability in a dose-dependent manner. Leaf extract of O. octandra has non-toxic in normal keratinocytes. Also, O. octandra extract interrupted the DNA replication via G1 phase arrests, and this effect was independent of ROS generation. In the apoptosis-related experiments, the population of annexin V-positive cells increased upon treatment with O. octandra extract. Furthermore, the expression of anti-apoptotic protein (Bcl-2 and Bcl-xL) was decreased, whereas the expression of cleaved caspase-3 protein was increased in O. octandra-treated OSCC cells.

Conclusions

The results suggest that a leaf extract of O. octandra inhibited the proliferation of OSCC cells through G₁ phase arrest and interrupting DNA replication. The leaf extract of O. octandra could trigger the apoptotic response via caspase 3 activation in OSCC cells. These results suggest that O. octandra has the potential to be developed as an alternative medicine for treating OSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03505-4.

AZD5153 reverses palbociclib resistance in ovarian cancer by inhibiting cell cycle-related proteins and the MAPK/PI3K-AKT pathway

The CDK4/6 inhibitor, palbociclib has recently entered clinic-trial stage for breast cancer treatment. However, translating its efficacy to other solid tumors has been challenging, especially for aggressive solid tumors. We found that the effect of palbociclib as a single agent was limited due to primary and acquired resistance in multiple ovarian cancer (OC) models. Among these, patient-derived organoid and xenograft models are two most representative models of drug responsiveness in patients with OC. In preclinical models, this study demonstrated that activated MAPK/PI3K-AKT pathway and cell cycle-related proteins induced the resistance to palbociclib, which was overcome by the addition of the bromodomain protein 4 (BRD4) inhibitor AZD5153. Moreover, this study revealed that AZD5153 and palbociclib had a synergistic lethal effect on inducing the cell cycle arrest and increasing apoptosis, even in RB-deficient cell lines. Based on these results, it is anticipated that this class of drugs, including AZD5153, which inhibit the cell cycle-related protein and MAPK/PI3K-AKT pathway, will exhibit synergistic effects with palbociclib in OC.

Carfilzomib: A Promising Proteasome Inhibitor for the Treatment of Relapsed and Refractory Multiple Myeloma

The proteasome is crucial for the degradation of intracellular proteins and plays an important role in mediating a number of cell survival and progression events by controlling the levels of key regulatory proteins such as cyclins and caspases in both normal and tumor cells. However, compared to normal cells, cancer cells are more dependent on the ubiquitin proteasome pathway (UPP) due to the accumulation of proteins in response to uncontrolled gene transcription, allowing proteasome to become a potent therapeutic target for human cancers such as multiple myeloma (MM). Up to date, three proteasome inhibitors namely bortezomib (2003), carfilzomib (2012) and ixazomib (2015) have been approved by the US Food and Drug Administration (FDA) for the treatment of patients with relapsed and/or refractory MM. This review mainly focuses on the biochemical properties, mechanism of action, toxicity profile and pivotal clinical trials related to carfilzomib, a second-generation proteasome inhibitor that binds irreversibly with proteasome to overcome the major toxicities and resistance associated with bortezomib.

Screening and identification of key genes in imatinib-resistant chronic myelogenous leukemia cells: a bioinformatics study

BACKGROUND

Chronic myelogenous leukemia (CML) is one of the most common cancers in the world. Imatinib is one of the most effective therapeutic strategies to inhibit the BCR-ABL tyrosine Kinase in patients with CML, but resistance is increasingly encountered.

MATERIAL AND METHODS

Microarray data GSE7114, GSE92624 and GSE97562 were downloaded and analyzed from Gene Expression Omnibus (GEO) to identify the candidate genes in the imatinib-resistant CML cells. The differentially expressed genes (DEGs) were appraised, and the protein-protein interaction (PPI) network was created by using STRING and Cytoscape.

RESULTS

We screened a total of 217 DEGs, including 151 upregulated genes and 66 downregulated genes. The enriched functions and pathways of genes include insulin-like growth factor I binding, cysteine-type endopeptidase inhibitor activity involved in apoptotic process, cell adhesion, positive regulation of nitric oxide biosynthetic process and hematopoietic cell lineage. Nine hub genes were appraised and Gene Ontology enrichment analysis revealed that these genes are mainly enriched in cell cycle, peptidase inhibitor activity and cell division. Several genes such as BIRC5, CCNE2 and MCM4 were identified in survival analysis and these genes alteration are significantly associated with worse overall survival and disease-free survival.

CONCLUSIONS

These genes have the potential to become surrogate markers for a clinical evaluation of imatinib-resistant CML patients. Our results provide potential target genes for diagnosis and treatment of imatinib-resistant CML patients.

Interleukin-32θ Triggers Cellular Senescence and Reduces Sensitivity to Doxorubicin-Mediated Cytotoxicity in MDA-MB-231 Cells

The recently discovered interleukin (IL)- 32 isoform IL-32θ exerts anti-metastatic effects in the breast tumor microenvironment. However, the involvement of IL-32θ in breast cancer cell proliferation is not yet fully understood; therefore, the current study aimed to determine how IL-32θ affects cancer cell growth and evaluated the responses of IL-32θ-expressing cells to other cancer therapy. We compared the functions of IL-32θ in triple-negative breast cancer MDA-MB-231 cells that stably express IL-32θ, with MDA-MB-231 cells transfected with a mock vector. Slower growth was observed in cells expressing IL-32θ than in control cells, and changes were noted in nuclear morphology, mitotic division, and nucleolar size between the two groups of cells. Interleukin-32θ significantly reduced the colony-forming ability of MDA-MB-231 cells and induced permanent cell cycle arrest at the G1 phase. Long-term IL-32θ accumulation triggered permanent senescence and chromosomal instability in MDA-MB-231 cells. Genotoxic drug doxorubicin (DR) reduced the viability of MDA-MB-231 cells not expressing IL-32θ more than in cells expressing IL-32θ. Overall, these findings suggest that IL-32θ exerts antiproliferative effects in breast cancer cells and initiates senescence, which may cause DR resistance. Therefore, targeting IL-32θ in combination with DR treatment may not be suitable for treating metastatic breast cancer.

MiR-377-3p inhibits atherosclerosis-associated vascular smooth muscle cell proliferation and migration via targeting neuropilin2

Vascular smooth muscle cell (VSMC) proliferation and migration are vital to atherosclerosis (AS) development and plaque rupture. MicroRNA-377-3p (miR-377-3p) has been reported to inhibit AS in apolipoprotein E knockout (ApoE^−/−) mice. Herein, the mechanism underlying the effect of miR-377-3p on alleviating AS is explored. In vivo experiments, ApoE^−/− mice were fed with high-fat diet (HFD) to induce AS and treated with miR-377-3p agomir or negative control agomir (agomir-NC) on week 0, 2, 4, 6, 8, 10 after HFD feeding. MiR-377-3p was found to restore HFD-induced AS lesions and expressions of matrix metalloproteinase (MMP)-2, MMP-9, α-smooth muscle actin (α-actin) and calponin. In in vitro experiments, human VSMCs were tranfected with miR-377-3p agomir or agomir-NC, followed by treatment with oxidized low-density lipoprotein (ox-LDL). MiR-377-3p was observed to significantly inhibit ox-LDL-induced VSMC proliferation characterized by inhibited cell viability, expressions of proliferating cell nuclear antigen (PCNA), cyclin D1 and cyclin E and cell cycle transition from G₁ to S phase accompanied with less 5-Ethynyl-2′-deoxyuridine (EdU)-positive cells. Furthermore, MiR-377-3p significantly inhibited ox-LDL-induced VSMC migration characterized by inhibited wound closure and decreased relative VSMC migration. Besides, neuropilin2 (NRP2) was verified as a target of miR-377-3p. MiR-377-3p was observed to inhibit NRP2 expressions in vivo and in vitro. Moreover, miR-377-3p significantly inhibited MMP-2 and MMP-9 expressions in human VSMCs. Additionally, miR-377-3p-induced inhibition of VSMC proliferation and migration could be attenuated by NRP2 overexpression. These results indicated that miR-377-3p inhibited VSMC proliferation and migration via targeting NRP2. The present study provides an underlying mechanism for miR-377-3p-based AS therapy.

Curcumin promotes cell cycle arrest and apoptosis of acute myeloid leukemia cells by inactivating AKT

Curcumin, a phytochemical from rhizomes of the plant Curcuma longa, has been reported to exert potential anticancer properties in various cancer types, including acute myeloid leukemia (AML). However, the underlying mechanism remains poorly understood. The present study demonstrated that curcumin had a stronger cytotoxic activity against AML cells compared with three other types of phytochemicals (epigallocatechin gallate, genistein and resveratrol). Protein phosphorylation profiling using an antibody array identified that curcumin treatment increased the phosphorylation levels of 14 proteins and decreased those of four proteins. A protein‑protein interaction network was constructed using the STRING database, in which AKT was identified as a hub protein with the highest connectivity (PRAS40, 4E‑BP1, P70S6K, RAF‑1 and p27). Western blotting results indicated that curcumin dose‑dependently suppressed the phosphorylation of AKT, PRAS40, 4E‑BP1, P70S6K, RAF‑1 and p27 in AML cell lines (ML‑2 and OCI‑AML5). It was also demonstrated that curcumin regulated the cell cycle‑ and apoptosis‑related proteins (cyclin D1, p21, Bcl2, cleaved‑caspase‑3 and cleaved‑PARP), leading to cell cycle arrest and apoptosis in both ML‑2 and OCI‑AML5 cells. These effects of curcumin were enhanced by the AKT inhibitor afuresertib but were suppressed by the AKT activator SC‑79, indicating that curcumin functions via AKT. In the AML xenograft mouse model, curcumin and afuresertib synergistically suppressed the engraftment, proliferation and survival of AML cells. Collectively, the present study demonstrated that curcumin exerted anti‑AML roles by inactivating AKT and these findings may aid in the treatment of AML.

The role of glycogen synthase kinase 3 (GSK3) in cancer with emphasis on ovarian cancer development and progression: A comprehensive review

Glycogen synthase kinase 3 (GSK3) is a monomeric serine-threonine kinase discovered in 1980 in a rat skeletal muscle. It has been involved in various cellular processes including embryogenesis, immune response, inflammation, apoptosis, autophagy, wound healing, neurodegeneration, and carcinogenesis. GSK3 exists in two different isoforms, GSK3α and GSK3β, both containing seven antiparallel beta-plates, a short linking part and an alpha helix, but coded by different genes and variously expressed in human tissues. In the current review, we comprehensively appraise the current literature on the role of GSK3 in various cancers with emphasis on ovarian carcinoma. Our findings indicate that the role of GSK3 in ovarian cancer development cannot be decisively determined as the currently available data support both prooncogenic and tumor-suppressive effects. Likewise, the clinical impact of GSK3 expression on ovarian cancer patients and its potential therapeutic implications are also limited. Further studies are needed to fully elucidate the pathophysiological and clinical implications of GSK3 activity in ovarian cancer.

TRIM47 Promotes the Development of Glioma by Ubiquitination and Degradation of FOXO1

Objective

To investigate the effect of TRIM47 on glioma cells and further explore its underlying molecular mechanisms.

Methods

Mouse xenograft model was used in this study. The mRNA expression of TRIM47 was detected by qRT-PCR. The cell viability and proliferation activity was detected by MTT assay and colony formation assay. The migration and invasion of glioma cells were determined by Transwell assay. The protein levels of TRIM47, FOXO1, CyclinD1, C-myc, MMP-2 and TIMP-1 were assessed by Western-blotting. The interaction between TRIM47 and FOXO1 was measured by Co-immunoprecipitation (Co-IP) assay.

Results

In glioma tissues and cells, TRIM47 was significantly up-regulated. Silencing the expression of TRIM47 inhibited the cell viability and proliferation of cells A172 and U251, as well as their ability to invade and migrate. Among them, the expression levels of C-myc and CyclinD1 also decreased, and MMP-2 was down-regulated and TIMP-1 was up-regulated. Similarly, in vivo model, tumor volume and weight also decreased after TRIM47 knockout. Further research showed that TRIM47 inhibited FOXO1 expression by ubiquitination and degradation of FOXO1, thereby promoting glioma growth and progression.

Conclusion

In our study, we confirmed functional role of the TRIM47-FOXO1 axis in the progression of gliomas and provided a potential target for glioma treatment.

Tweaking EMT and MDR dynamics to constrain triple-negative breast cancer invasiveness by EGFR and Wnt/β-catenin signaling regulation

PURPOSE

Due to a lack of effective targeted therapies, patients with metastatic triple-negative breast cancer (TNBC) have poor clinical outcomes. Epithelial to mesenchymal transition (EMT) is known to contribute to cancer progression, invasiveness and multidrug resistance (MDR). There is a strong correlation between various drug efflux mechanisms, cancer stem cells and tumor microenvironments, which in turn is synchronized by complex signaling crosstalk between EMT and MDR. We hypothesize that combining these regulatory connections with targeted combinatorial therapies may be an effective approach to annihilate the progression/metastasis of TNBC.

METHODS

AlamarBlue assays were used to depict TNBC cell viability, whereas flow cytometry was used to detect apoptotic cell populations, reactive-oxygen species (ROS) levels as well as mitochondrial depolarization. qRT-PCR, Western blotting and confocal microscopy were used to provide molecular-level information of the genes and proteins involved.

RESULTS

Our initial analyses showed that targeting EGFR by either erlotinib (EGFR inhibitor) or lapatinib (EGFR/HER-2 inhibitor) alone was ineffective against TNBC. Interestingly, we subsequently found that a low dose of lapatinib did act as a substrate rather than as an inhibitor facilitating EMT and MDR, leading to metastasis. Additional gene expression studies indicated that co-targeting the EGFR and Wnt/β-catenin pathways with lapatinib and XAV939 (a tankyrase inhibitor) promoted mesenchymal to epithelial transition (MET). Application of these inhibitors led to a 5.62-fold increase in the epithelial marker E-cadherin and a 3.33-fold decrease in the stemness marker EpCAM, with concomitant 1.5-fold and 3.22-fold reductions in the ABC transporters ABCB1 and ABCG2, respectively. These co-targeting effects resulted in overcoming EMT and MDR, which in turn was highlighted by reduced levels of pEGFR, pAKT, pMAPK, pSTAT-3, pGSK-3β and β-catenin.

CONCLUSIONS

Our data indicate that the synergistic action of targeting both the EGFR and Wnt/β-catenin signaling pathways in TNBC cells may open up new avenues for combatting this disease.

BCL-2 Inhibitor Venetoclax Induces Autophagy-Associated Cell Death, Cell Cycle Arrest, and Apoptosis in Human Breast Cancer Cells

Introduction

Venetoclax (VCX) is a selective BCL-2 inhibitor approved for the treatment of leukemia and lymphoma. However, the mechanisms of anti-cancer effect of VCX either as a monotherapy or in combination with other chemotherapeutic agents against breast cancer need investigation.

Methods

Breast cancer cell lines with different molecular subtypes (MDA-MB-231, MCF-7, and SKBR-3) were treated with different concentrations of VCX for indicated time points. The expression of cell proliferative, apoptotic, and autophagy genes was determined by qRT-PCR and Western blot analyses. In addition, the percentage of MDA-MB-231 cells underwent apoptosis, expressed higher oxidative stress levels, and the changes in the cell cycle phases were determined by flow cytometry.

Results

Treatment of human breast cancer cells with increasing concentrations of VCX caused a significant decrease in cells growth and proliferation. This effect was associated with a significant increase in the percentage of apoptotic MDA-MB-231 cells and in the expression of the apoptotic genes, caspase 3, caspase 7, and BAX, with inhibition of anti-apoptotic gene, BCL-2 levels. Induction of apoptosis by VCX treatment induced cell cycle arrest at G0/G1 phase with inhibition of cell proliferator genes, cyclin D1 and E2F1. Furthermore, VCX treatment increased the formation of reactive oxygen species and the expression level of autophagy markers, Beclin 1 and LC3-II. Importantly, these cellular changes by VCX increased the chemo-sensitivity of MDA-MB-231 cells to doxorubicin.

Discussion

The present study explores the molecular mechanisms of VCX-mediated inhibitory effects on the growth and proliferation of TNBC MDA-MB-231 cells through the induction of apoptosis, cell cycle arrest, and autophagy. The study also explores the role of BCL-2 as a novel targeted therapy for breast cancer.

Identification of key genes of hesperidin in inhibition of breast cancer stem cells by functional network analysis

Breast cancer therapy with classical chemotherapy is unable to eradicate breast cancer stem cells (BCSCs). Loss of p53 function causes growth and differentiation in cancer stem cells (CSCs); therefore, p53-targeted compounds can be developed for BCSCs-targeted drugs. Previously, hesperidin (HES), a citrus flavonoid, showed anticancer activities and increased efficacy of chemotherapy in several types of cancer in vitro and in vivo. This study was aimed to explore the key protein and molecular mechanism of hesperidin in the inhibition of BCSCs using bioinformatics and in vitro study. Bioinformatics analysis revealed about 75 potential therapeutic target proteins of HES in BCSCs (TH), in which TP53 was the only direct target protein (DTP) with a high degree score. Furthermore, the results of GO enrichment analysis showed that TH was taken part in the biological process of regulation of apoptosis and cell cycle. The KEGG pathway enrichment analysis also showed that TH is involved in several pathways, including cell cycle, p53 signaling pathway. In vitro experiment results showed that HES inhibited cell proliferation, mammosphere, and a colony formation, and migration in on MCF-7 3D cells (mammospheres). HES induced G0/G1 cell cycle arrest and apoptosis in MCF-7 cells 3D. In addition, HES treatment reduced the mRNA level of p21 but increased the mRNA level of cyclin D1 and p53 in the mammosphere. HES inhibits BCSCs in mammospheres. More importantly, this study highlighted p53 as a key protein in inhibition of BCSCs by HES. Future studies on the molecular mechanism are needed to validate the results of this study.

A novel indenone derivative selectively induces senescence in MDA-MB-231 (breast adenocarcinoma) cells

Triple-negative breast cancer is the most aggressive form of breast cancer with limited intervention options. Moreover, a number of belligerent therapeutic strategies adopted to treat such aggressive forms of cancer have demonstrated detrimental side effects. This necessitates exploration of targeted chemotherapeutics. We assessed the efficacy of a novel indenone derivative (nID) [(±)-N-(2-(-5-methoxy-1-oxo-3-(2-oxo-2-phenylethyl)-2,3-dihydro-1H-inden-2-yl)ethyl)-4-methylbenzenesulfonamide], synthesized by a novel internal nucleophile-assisted palladium-catalyzed hydration-olefin insertion cascade; against triple-negative breast cancer cells (MDA-MB-231). On 24 h treatment, the nID caused decline in the viability of MDA-MB-231 and MDA-MB-468 cells, but did not significantly (P < 0.05) affect WRL-68 (epithelial-like) cells. In fact, the nID demonstrated augmentation of p53 expression, and consequent p53-dependent senescence in both MDA-MB-231 and MDA-MB-468 cells, but not in WRL-68 cells. The breast cancer cells also exhibited reduced proliferation, downregulated p65/NF-κB and survivin, along with augmented p21Cip1/WAF1 expression, on treatment with the nID. This ensued cell cycle arrest at G1 stage, which might have driven the MDA-MB-231 cells to senescence. We observed a selectivity of the nID to target MDA-MB-231 cells, whereas WRL-68 cells did not show any considerable effect. The results underscored that the nID has potential to be developed into a cancer therapeutic.

Citrus hystrix Extracts Protect Human Neuronal Cells against High Glucose-Induced Senescence

Citrus hystrix (CH) is a beneficial plant utilized in traditional folk medicine to relieve various health ailments. The antisenescent mechanisms of CH extracts were investigated using human neuroblastoma cells (SH-SY5Y). Phytochemical contents and antioxidant activities of CH extracts were analyzed using a gas chromatograph–mass spectrometer (GC-MS), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) assay and 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assay. Effects of CH extracts on high glucose-induced cytotoxicity, reactive oxygen species (ROS) generation, cell cycle arrest and cell cycle-associated proteins were assessed using a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium (MTT) assay, non-fluorescent 2′, 7′-dichloro-dihydrofluorescein diacetate (H₂DCFDA) assay, flow cytometer and Western blot. The extracts protected neuronal senescence by inhibiting ROS generation. CH extracts induced cell cycle progression by releasing senescent cells from the G1 phase arrest. As the Western blot confirmed, the mechanism involved in cell cycle progression was associated with the downregulation of cyclin D1, phospho-cell division cycle 2 (pcdc2) and phospho-Retinoblastoma (pRb) proteins. Furthermore, the Western blot showed that extracts increased Surtuin 1 (SIRT1) expression by increasing the phosphorylation of Glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Collectively, CH extracts could protect high glucose-induced human neuronal senescence by inducing cell cycle progression and up-regulation of SIRT1, thus leading to the improvement of the neuronal cell functions.

The proteasome as a druggable target with multiple therapeutic potentialities: Cutting and non-cutting edges

Ubiquitin Proteasome System (UPS) is an adaptable and finely tuned system that sustains proteostasis network under a large variety of physiopathological conditions. Its dysregulation is often associated with the onset and progression of human diseases; hence, UPS modulation has emerged as a promising new avenue for the development of treatments of several relevant pathologies, such as cancer and neurodegeneration. The clinical interest in proteasome inhibition has considerably increased after the FDA approval in 2003 of bortezomib for relapsed/refractory multiple myeloma, which is now used in the front-line setting. Thereafter, two other proteasome inhibitors (carfilzomib and ixazomib), designed to overcome resistance to bortezomib, have been approved for treatment-experienced patients, and a variety of novel inhibitors are currently under preclinical and clinical investigation not only for haematological malignancies but also for solid tumours. However, since UPS collapse leads to toxic misfolded proteins accumulation, proteasome is attracting even more interest as a target for the care of neurodegenerative diseases, which are sustained by UPS impairment. Thus, conceptually, proteasome activation represents an innovative and largely unexplored target for drug development. According to a multidisciplinary approach, spanning from chemistry, biochemistry, molecular biology to pharmacology, this review will summarize the most recent available literature regarding different aspects of proteasome biology, focusing on structure, function and regulation of proteasome in physiological and pathological processes, mostly cancer and neurodegenerative diseases, connecting biochemical features and clinical studies of proteasome targeting drugs.

Antiproliferative Effects of Monoclonal Antibodies against (Pro)Renin Receptor in Pancreatic Ductal Adenocarcinoma

We previously reported that silencing of the PRR gene, which encodes the (pro)renin receptor [(P)RR], significantly reduced Wnt/β-catenin-dependent development of pancreatic ductal adenocarcinoma (PDAC). Here, we examined the effects of a panel of blocking mAbs directed against the (P)RR extracellular domain on proliferation of the human PDAC cell lines PK-1 and PANC-1 in vitro and in vivo We observed that four rat anti-(P)RR mAbs induced accumulation of cells in the G₀-G₁-phase of the cell cycle and significantly reduced proliferation in vitro concomitant with an attenuation of Wnt/β-catenin signaling. Systemic administration of the anti-(P)RR mAbs to nude mice bearing subcutaneous PK-1 xenografts significantly decreased tumor expression of active β-catenin and the proliferation marker Ki-67, and reduced tumor growth. In contrast, treatment with the handle region peptide of (pro)renin did not inhibit tumor growth in vitro or in vivo, indicating that the effects of the anti-(P)RR mAbs were independent of the renin-angiotensin system. These data indicate that mAbs against human (P)RR can suppress PDAC cell proliferation by hindering activation of the Wnt/β-catenin signaling pathway. Thus, mAb-mediated (P)RR blockade could be an attractive therapeutic strategy for PDAC.

Complementary Targeting of Rb Phosphorylation and Growth in Cervical Cancer Cell Cultures and a Xenograft Mouse Model by SHetA2 and Palbociclib

Cervical cancer is caused by high-risk human papillomavirus (HPV) types and treated with conventional chemotherapy with surgery and/or radiation. HPV E6 and E7 proteins increase phosphorylation of retinoblastoma (Rb) by cyclin D1/cyclin dependent kinase (CDK)4/6 complexes. We hypothesized that cyclin D1 degradation by the SHetA2 drug in combination with palbociclib inhibition of CDK4/6 activity synergistically reduces phosphorylated Rb (phospho-Rb) and inhibits cervical cancer growth. The effects of these drugs, alone, and in combination, were evaluated in SiHa and CaSki HPV-positive and C33A HPV-negative cervical cancer cell lines using cell culture, western blots and ELISA, and in a SiHa xenograft model. Endpoints were compared by isobolograms, ANOVA, and Chi-Square. In all cell lines, combination indexes documented synergistic interaction of SHetA2 and palbociclib in association SHetA2 reduction of cyclin D1 and phospho-Rb, palbociclib reduction of phospho-Rb, and enhanced phospho-Rb reduction upon drug combination. Both drugs significantly reduced phospho-Rb and growth of SiHa xenograft tumors as single agents and acted additively when combined, with no evidence of toxicity. Dilated CD31-negative blood vessels adjacent to, or within, areas of necrosis and apoptosis were observed in all drug-treated tumors. These results justify development of the SHetA2 and palbociclib combination for targeting phospho-Rb in cervical cancer treatment.

Antibiotic tigecycline inhibits cell proliferation, migration and invasion via down-regulating CCNE2 in pancreatic ductal adenocarcinoma

Recently, many researches have reported that antibiotic tigecycline has significant effect on cancer treatment. However, biomedical functions and molecular mechanisms of tigecycline in human pancreatic ductal adenocarcinoma (PDAC) remain unclear. In the current study, we tried to assess the effect of tigecycline in PDAC cells. AsPC‐1 and HPAC cells were treated with indicated concentrations of tigecycline for indicated time, and then, MTT, BrdU and soft agar assay were used to test cell proliferation. The effect of tigecycline on cell cycle and cellular apoptosis was tested by cytometry. Migration and invasion were detected by wound healing assay and transwell migration/invasion assay. Expressions of cell cycle‐related and migration/invasion‐related protein were determined by using Western blot. The results revealed that tigecycline observably suppressed cell proliferation by inducing cell cycle arrest at G0/G1 phase and blocked cell migration/invasion via holding back the epithelial‐mesenchymal transition (EMT) process in PDAC. In addition, tigecycline also remarkably blocked tumorigenecity in vivo. Furthermore, the effects of tigecycline alone or combined with gemcitabine in vitro or on PDAC xenografts were also performed. The results showed that tigecycline enhanced the chemosensitivity of PDAC cells to gemcitabine. Interestingly, we found CCNE2 expression was declined distinctly after tigecycline treatment. Then, CCNE2 was overexpressed to rescue tigecycline‐induced effect. The results showed that CCNE2 overexpression significantly rescued tigecycline‐inhibited cell proliferation and migration/invasion. Collectively, we showed that tigecycline inhibits cell proliferation, migration and invasion via down‐regulating CCNE2, and tigecycline might be used as a potential drug for PDAC treatment alone or combined with gemcitabine.

Vaginal Suppositories Containing SHetA2 to Treat Cervical Dysplasia: Pharmacokinetics of Daily Doses and Preliminary Safety Profile

SHetA2 is a new drug with potential to treat cervical dysplasia, but only 0.02% of the dose is absorbed into the cervix after oral administration. By contrast, 23.9% of the dose is absorbed into the cervix after vaginal administration. This study determines the pharmacokinetic and pharmacodynamic parameters after daily vaginal doses of SHetA2 in suppositories and assesses its safety. Daily dosed mice maintained therapeutic concentrations of SHetA2 in the cervix for 65 h. The steady-state area under the curve concentration versus time (AUC_cervix) after the last dose was similar to that after a single dose indicating that there was no drug accumulation in the cervix. By contrast, the maximum drug concentration (C_max-cervix) was smaller in the daily dosed group (52.19 μg/g) than after a single dose (121.84 μg/g), whereas the half-life (t_1/2-cervix) was also shorter in the daily dosed group (9.94 h) than after a single dose (23.32 h). Notably, daily vaginal doses of SHetA2 reduced the levels of cyclin D1 (the pharmacodynamic endpoint) to a larger extent (∼45%) than after the administration of a single dose (∼26%). No adverse effects were observed in the mice for the duration of the study; thus, daily vaginal doses of SHetA2 appear to be safe.

Wogonin inhibits cell cycle progression by activating the glycogen synthase kinase-3 beta in hepatocellular carcinoma

BACKGROUND

Wogonin has been reported to exhibit various biological activities such as anti-inflammation, anti-microbial, and anti-tumor. Previous studies have demonstrated that wogonin could down-regulate Cyclin D1 activity on multiple cancers. However, the related mechanisms have not been fully elucidated so far.

PURPOSE

The aim of the current study was to explore whether wogonin can suppress hepatocellular carcinoma (HCC) progression and the mechanism of wogonin in inhibiting Cyclin D1 expression.

METHODS

Herein, we assessed the anti-tumor activity of wogonin against hepatocellular carcinoma (HCC) by MTT assay, clonogenic assay, cell cycle analysis and orthotopic xenograft mouse models. Western blot, immunofluoscence assay, co-immunoprecipitation assay, docking program, surface plasmon resonance, site-directed mutagenesis assay and immunohistochemical assay were performed for exploring the underlying mechanisms of wogonin-induced growth inhibition in HCC.

RESULTS

Our results showed that non-toxic dosage of wogonin (10, 20 µM) could inhibit cells proliferation and suppress cells cycle progression in MHCC97L and HepG2 cell. Moreover, the findings from the western blot and immunofluoscence assay confirmed the inhibition action of wogonin (10, 20 µM) on Cyclin D1 expression in MHCC97L cells, and wogonin (10, 20 µM) pre-treatment was capable of promoting Cyclin D1 ubiquitination and degradation in MHCC97L cell. In addition, wogonin promoted phosphorylation of Cyclin D1 on threonine-286 site, the mutation of threonine-286 to alanine-286A blocked Cyclin D1 proteolysis induced by wogonin. Wogonin-promoted Cyclin D1 phosphorylation and subsequent proteolysis may associate with the activation of GSK3beta in cancer cells. The phosphorylated form of GSK3beta (active form) expression was significantly increased after wogonin (20 µM) exposure. Molecular docking study and Biacore SPR analysis of GSK3beta mutant further validated the high-affinity wogonin binding site on GSK3beta. Moreover, in vivo studies further confirmed that phospho-GSK3beta Tyr216 was over-expressed in HCC specimens after wogonin treatment while the amount of Cyclin D1 was significantly decreased.

CONCLUSION

In summary, our data reveal a novel molecular mechanism by which wogonin induces HCC cells cycle arrest and suppresses tumor proliferation.

Physiologically Based Pharmacokinetic Modeling and Tissue Distribution Characteristics of SHetA2 in Tumor-Bearing Mice

The orally available novel small molecule SHetA2 is the lead sulfur-containing heteroarotinoid that selectively inhibits cancer cells over normal cells, and is currently under clinical development for anticancer treatment and cancer prevention. The objective of this study was to assess and characterize the tissue distribution of SHetA2 in tumor-bearing mice by developing a physiologically based pharmacokinetic (PBPK) model. An orthotopic SKOV3 ovarian cancer xenograft mouse model was used to most accurately mimic the ovarian cancer tumor microenvironment in the peritoneal cavity. SHetA2 concentrations in plasma and 14 different tissues were measured at various time points after a single intravenous dose of 10 mg/kg and oral dose of 60 mg/kg, and these data were used to develop a whole-body PBPK model. SHetA2 exhibited a multi-exponential plasma concentration decline with an elimination half-life of 4.5 h. Rapid and extensive tissue distribution, which was best described by a perfusion rate-limited model, was observed with the tissue-to-plasma partition coefficients (k_p = 1.4-21.2). The PBPK modeling estimated the systemic clearance (76.4 mL/h) from circulation as a main elimination pathway of SHetA2. It also indicated that the amount absorbed into intestine was the major determining factor for the oral bioavailability (22.3%), while the first-pass loss from liver and intestine contributed minimally (< 1%). Our results provide an insight into SHetA2 tissue distribution characteristics. The developed PBPK model can be used to predict the drug exposure at tumors or local sites of action for different dosing regimens and scaled up to humans to correlate with efficacy.

Vitamin C supplementation had no side effect in non-cancer, but had anticancer properties in ovarian cancer cells

Vitamin C (Vit C) has been widely used in the treatment and prevention of cancer. Nevertheless, the clinical results are still inconclusive. Using non-cancer (HOSEpiC) and cancer OVCAR-3 cells cultured in basal medium or in ovarian cancer-associated fibroblast (CAF)-supplemented medium, we estimated the dose-dependent effect of Vit C on sodium-ascorbate co-transporters (SVCT1, SVCT2) and glucose transporter (GLUT1) protein expression. Additionally, the action of Vit C on cell proliferation (alamarBlue), membrane permeability (LDH assay), caspase3 activity, the selected cell cycle and apoptosis pathway, poly(ADP-ribose) polymerase-1 (PARP) protein expression, and reactive oxygen species (ROS) activity was determined. We showed different effects of Vit C on the expression of the co-transporter in non-cancer and cancer cells. In non-cancer cells, Vit C, at a pharmacological concentration, increased SVCT2 and decreased GLUT1, while the opposite effect was noted in cancer cells. In cancer cells, Vit C, in a pharmacological dose, decreased cell proliferation through an inhibitory effect on cyclin-dependent kinase 2 (CDK2) (4.4-fold; p < 0.01), mainly due to the stimulatory effect on the expression of cyclin-dependent kinase (CDK) inhibitors, such as p21 and p53 (3.2- and 2.8-fold, respectively; p < 0.001), but not caspase pathway. The tumour microenvironment caused inefficiency of the lower doses of Vit C in ovarian cancer cells. At a pharmacological dose of 1 mM, Vit C decreased PARP expression (1.5-fold; p < 0.05). We suggest that it's nontoxic effects on non-cancer cells may be an indicator of its prophylactic use, while in a pharmacological dose Vit C should be considered a possible adjunctive drug in ovarian cancer. However, it is necessary to consider the effect of the CAF.

Novel ovarian cancer maintenance therapy targeted at mortalin and mutant p53

Current ovarian cancer maintenance therapy is limited by toxicity and no proven impact on overall survival. To study a maintenance strategy targeted at missense mutant p53, we hypothesized that the release of mutant p53 from mortalin inhibition by the SHetA2 drug combined with reactivation of mutant p53 with the PRIMA-1^MET drug inhibits growth and tumor establishment synergistically in a mutant-p53 dependent manner. The Cancer Genome Atlas (TCGA) data and serous ovarian tumors were evaluated for TP53 and HSPA9/mortalin status. SHetA2 and PRIMA-1^MET were tested in ovarian cancer cell lines and fallopian tube secretory epithelial cells using isobolograms, fluorescent cytometry, Western blots and ELISAs. Drugs were administered to mice after peritoneal injection of MESOV mutant p53 ovarian cancer cells and prior to tumor establishment, which was evaluated by logistic regression. Fifty-eight percent of TP53 mutations were missense and there were no mortalin mutations in TCGA high-grade serous ovarian cancers. Mortalin levels were sequentially increased in serous benign, borderline and carcinoma tumors. SHetA2 caused p53 nuclear and mitochondrial accumulation in cancer, but not in healthy, cells. Endogenous or exogenous mutant p53 increased SHetA2 resistance. PRIMA-1^MET decreased this resistance and interacted synergistically with SHetA2 in mutant and wild type p53-expressing cell lines in association with elevated reactive oxygen species/ATP ratios. Tumor-free rates in animals were 0% (controls), 25% (PRIMA1^MET ), 42% (SHetA2) and 67% (combination). SHetA2 (p = 0.004) and PRIMA1^MET (p = 0.048) functioned additively in preventing tumor development with no observed toxicity. These results justify the development of SHetA2 and PRIMA-1^MET alone and in combination for ovarian cancer maintenance therapy.

Enantiomer of the novel flexible heteroarotinoid, SL-1-09, blocks cell cycle progression in breast cancer cells

Flexible heteroarotinoids (Flex-Hets) are compounds with promising anti-cancer activities. SHetA2, a first-generation Flex-Het, has been shown to inhibit the growth of cervical, head and neck, kidney, lung, ovarian, prostate, and breast cancers. However, SHetA2's high lipophilicity, limited selectivity, low oral bioavailability, and complicated synthesis has led to the development of second-generation compounds, such as 1-(1-(naphthalen-1-yl)ethyl)-3-(4-nitrophenyl) thiourea or SL-1-09. Results from our lab show that SL-1-09 exhibits anti-cancer activities against ERα+ and ERα- breast cancer cells at micromolar concentrations. SL-1-09 is a mixture of two enantiomers, R and S. The objective of this study was to further analyze these enantiomers to determine their individual anti-cancer activities. Cell cycle analysis demonstrated that the percentage of cells in S-phase is reduced significantly when breast cancer cell lines MCF-7, T47D and MDA-MB-453 cells are treated with 5.0 μM of the S enantiomer. Consistent with this finding, treatment of these cells with the S enantiomer resulted in lower expression levels of cell cycle proteins. Overall, our data indicate that the S enantiomer shows greater growth inhibitory effects than the R form against ERα+ (MCF7 and T47D) and ERα- (MDA-MB-453) breast cancer cells, suggesting that the activity observed in SL-1-09 is most likely due to the ability of the S enantiomer to block cell cycle progression.

NK007 helps in mitigating paclitaxel resistance through p38MAPK activation and HK2 degradation in ovarian cancer

Ovarian cancer resistance to available medicines is a huge challenge in dire need of a solution, which makes its recurrence and mortality rate further exacerbated. A promising approach to overcome chemoresistance is drug screening from natural products. Here, we report that NK007, a (±)-tylophorine malate isolated from the Asclepiadaceae family, selectively inhibited the proliferation of A2780 and A2780 (Taxol) cells and migration of paclitaxel-sensitive and -resistant ovarian cancer cells. Interestingly, the decline of cell viability, including cell multiplication, clonality, and migration capacity was independent on cell apoptosis. At the molecular level, NK007 considerably induced G1/S arrest and upregulated the expression of phospho-p38 mitogen-activated protein kinase (p-p38MAPK). In addition, hexokinase 2 (HK2) protein degradation was considerably elevated in the presence of NK007, which resulted in the reduction of oxygen consumption rate and extracellular acidification rate. Altogether, our results indicate that NK007, an analog of tylophorine, can overcome paclitaxel (PTX) resistance through p38MAPK activation and HK2 degradation. As an effective, alternative antiresistance agent, NK007 exhibits a promising potential to treat PTX-resistant ovarian cancer.

MicroRNA-139 is a predictor of prostate cancer recurrence and inhibits growth and migration of prostate cancer cells through cell cycle arrest and targeting IGF1R and AXL

BACKGROUND

We previously identified a panel of five microRNAs (miRNAs) associated with biochemical recurrence and metastasis following prostatectomy from prostate cancer patients using next-generation sequencing-based whole miRNome sequencing and quantitative polymerase chain reaction-based validation analysis. In this study, we examined the mechanism of action of miR-139-5p, one of the downregulated miRNAs identified in the panel.

METHODS

Using a cohort of 585 patients treated with radical prostatectomy, we examined the prognostic significance of miR-139 (dichotomized around the median) using the Kaplan-Meier method and Cox proportional hazard models. We validated these results using The Cancer Genome Atlas (TCGA) data. We created cell lines that overexpressed miR-139 to confirm its targets as well as examine pathways through which miR-139 may function using cell-based assays.

RESULTS

Low miR-139 expression was significantly associated with a variety of prognostic factors in prostate cancer, including Gleason score, pathologic stage, margin positivity, and lymph node status. MiR-139 expression was associated with prognosis: the cumulative incidence of biochemical recurrence and metastasis were significantly lower among patients with high miR-139 expression (P = .0004 and .038, respectively). Validation in the TCGA data set showed a significant association between dichotomized miR-139 expression and biochemical recurrence (odds ratio, 0.52; 95% confidence interval, 0.33-0.82). Overexpression of miR-139 in prostate cancer cells led to a significant reduction in cell proliferation and migration compared with control cells, with cells arrested in G2 of cell cycle. IGF1R and AXL were identified as potential targets of miR-139 based on multiple miRNA-binding sites in 3'-untranslated regions of both the genes and their association with prostate cancer growth pathways. Luciferase assays verified AXL and IGF1R as direct targets of miR-139. Furthermore, immunoblotting of prostate cancer cells demonstrated IGF1R and AXL protein expression were inhibited by miR-139 treatment, which was reversed by the addition of miR-139 antagomir. Examination of the molecular mechanism of growth inhibition by miR-139 revealed the downregulation of activated AKT and cyclin D1, with upregulation of the CDK inhibitor p21.

CONCLUSIONS

miR-139 is associated with improved prognosis in patients with localized prostate cancer, which may be mediated through downregulation of IGF1R and/or AXL and associated signaling pathway components.

Ivermectin induces apoptosis of porcine trophectoderm and uterine luminal epithelial cells through loss of mitochondrial membrane potential, mitochondrial calcium ion overload, and reactive oxygen species generation

Ivermectin is a pesticide that has been used for over 30 years in livestock. Although there are a number of studies on the therapeutic potential of ivermectin, little is known about the effects of the drug during the early stage of pregnancy. In this study, we investigated the detrimental effects of ivermectin on porcine trophectoderm (pTr) and uterine luminal epithelial (pLE) cells. Ivermectin not only inhibited the proliferation of both cells via the regulation of cell cycle-associated genes, but also induced apoptosis in pTr and pLE cells. We also verified its effect on mitochondrial dysfunction as shown by loss of mitochondrial membrane potential, mitochondrial Ca²⁺ overload, and reactive oxygen species (ROS) generation in pTr and pLE cells. As a mechanistic approach, we evaluated ivermectin-mediated cell signaling interactions including PI3K, AKT and MAPK pathways. Overall, our results suggest that constant exposure to and accumulation of ivermectin may cause abnormal fetal morphogenesis and placentation during the early stages of pregnancy. Our results may further provide a comprehensive understanding of the detrimental effects of ivermectin during pregnancy and will contribute to the establishment of a complete safety profile for ivermectin and its association with environmental pollution and public health in humans and livestock.

DNA damage response and repair in ovarian cancer: Potential targets for therapeutic strategies

Ovarian cancer is among the most lethal gynecologic malignancies with a poor survival prognosis. The current therapeutic strategies involve surgery and chemotherapy. Research is now focused on novel agents especially those targeting DNA damage response (DDR) pathways. Understanding the DDR process in ovarian cancer necessitates having a detailed knowledge on a series of signaling mediators at the cellular and molecular levels. The complexity of the DDR process in ovarian cancer and how this process works in metastatic conditions is comprehensively reviewed. For evaluating the efficacy of therapeutic agents targeting DNA damage in ovarian cancer, we will discuss the components of this system including DDR sensors, DDR transducers, DDR mediators, and DDR effectors. The constituent pathways include DNA repair machinery, cell cycle checkpoints, and apoptotic pathways. We also will assess the potential of active mediators involved in the DDR process such as therapeutic and prognostic candidates that may facilitate future studies.

Development and validation of a reverse phase HPLC method for SHetA2, a novel anti-cancer drug, in mouse biological samples

SHetA2 is a flexible heteroarotinoid that has the potential to prevent and treat lung, ovarian and cervical cancer without significant toxicity. A simple and reliable high performance liquid chromatographic (HPLC) method was developed to determine SHetA2 concentrations in the lungs, reproductive organs and plasma of mice. SHetA2 was extracted from these biological matrices by solid phase and liquid-liquid extraction in the presence of 4% H₃PO₄ and acetonitrile followed by filtration through a Captiva^® filtration plate. Drug concentrations in the filtrates were quantified by a Waters HPLC Alliance system coupled with XBridge^® C₁₈ column, guard column and UV detection at 361 nm. The mobile phase consisted of methanol and 0.25 N sodium acetate buffer (80:20, v/v) at pH: 3. SHetA2 was eluted after 5.35 and 6.14 min for tissues and plasma, respectively. Recovery of SHetA2 from biological samples was more than 95% of the spiked amount in tissues and more than 80% of the spiked amount in plasma. The limit of detection (LOD) was 0.005 μg/mL and the limit of quantitation (LOQ) was 0.025 μg/mL, which were 280 and 56 times lower than the predicted therapeutic concentration of SHetA2, respectively. The method was suitable to quantify SHetA2 concentrations in biological matrices from animal studies administering the drug by the vaginal, pulmonary and oral routes that had the purpose of determining the pharmacokinetic parameters of drug disposition. The HPLC method developed meets the ICH Harmonized Tripartite Guideline of a reliable, sensitive, reproducible and accurate method to be used in the determination of drug concentrations in biological samples.

Estrogen Receptor Beta (ERβ) Mediated-CyclinD1 Degradation via Autophagy Plays an Anti-Proliferation Role in Colon Cells

Dysfunction of autophagic degradation machinery causes tumorigenesis, including colorectal cancer (CRC). Overexpression of CyclinD1 in CRC has been reported. Recent evidence also suggests that ERβ deficiency is related to the pathogenesis of CRC. Very little is known, however, about the detailed molecular mechanisms underlying the relationship among ERβ, autophagy, and CyclinD1 in CRC. Here, results showed that ERβ played an anti-proliferation role in HCT116 through impairing cell cycle but not apoptosis. Additionally, CyclinD1 accumulation was increased in response to chloroquine (CQ) or in MEF Atg7 knockout cells. Further, ERβ could inhibit the mammalian target of rapamycin (mTOR) or activate Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNIP3) to promote autophagy in HCT116. In summary, these results indicate that ERβ-mediated CyclinD1 degradation can inhibit colon cancer cell growth via autophagy.

Novel flexible heteroarotinoid, SL-1-39, inhibits HER2-positive breast cancer cell proliferation by promoting lysosomal degradation of HER2

SL-1-39 [1-(4-chloro-3-methylphenyl)-3-(4-nitrophenyl)thiourea] is a new flexible heteroarotinoid (Flex-Het) analog derived from the parental compound, SHetA2, previously shown to inhibit cell growth across multiple cancer types. The current study aims to determine growth inhibitory effects of SL-1-39 across the different subtypes of breast cancer cells and delineate its molecular mechanism. Our results demonstrate that while SL-1-39 blocks cell proliferation of all breast cancer subtypes tested, it has the highest efficacy against HER2+ breast cancer cells. Molecular analyses suggest that SL-1-39 prevents S phase progression of HER2+ breast cancer cells (SKBR3 and MDA-MB-453), which is consistent with reduced expression of key cell-cycle regulators at both the protein and transcriptional levels. SL-1-39 treatment also decreases the protein levels of HER2 and pHER2 as well as its downstream effectors, pMAPK and pAKT. Reduction of HER2 and pHER2 at the protein level is attributed to increased lysosomal degradation of total HER2 levels. This is the first study to show that a flexible heteroarotinoid analog modulates the HER2 signaling pathway through lysosomal degradation, and thus further warrants the development of SL-1-39 as a therapeutic option for HER2+ breast cancer.