Key genes and molecular mechanisms related to Paclitaxel Resistance

Paclitaxel is commonly used to treat breast, ovarian, lung, esophageal, gastric, pancreatic cancer, and neck cancer cells. Cancer recurrence is observed in patients treated with paclitaxel due to paclitaxel resistance emergence. Resistant mechanisms are observed in cancer cells treated with paclitaxel, docetaxel, and cabazitaxel including changes in the target molecule β-tubulin of mitosis, molecular mechanisms that activate efflux drug out of the cells, and alterations in regulatory proteins of apoptosis. This review discusses new molecular mechanisms of taxane resistance, such as overexpression of genes like the multidrug resistance genes and EDIL3, ABCB1, MRP1, and TRAG-3/CSAG2 genes. Moreover, significant lncRNAs are detected in paclitaxel resistance, such as lncRNA H19 and cross-resistance between taxanes. This review contributed to discovering new treatment strategies for taxane resistance and increasing the responsiveness of cancer cells toward chemotherapeutic drugs.

Differential Sensitivity to Ionizing Radiation in Gemcitabine-Resistant and Paclitaxel-Resistant Pancreatic Cancer Cells

PURPOSE

Chemoresistance remains a major challenge in treating pancreatic ductal adenocarcinoma (PDAC). Although chemoradiation has proven effective in other tumor types, such as head and neck squamous cell carcinoma, its role in PDAC and effect on acquired chemoresistance have yet to be fully explored. In this study, we investigated the sensitivity of gemcitabine-resistant (GR) and paclitaxel-resistant (PR) PDAC cells to ionizing radiation (IR) and their underlying mechanisms.

METHODS AND MATERIALS

GR and PR clones were generated from PANC-1, PATU-T, and SUIT2-007 pancreatic cancer cell lines. Cell survival after radiation was assessed using clonogenic assay, sulforhodamine B assay, apoptosis, and spheroid growth by bioluminescence. Radiation-induced DNA damage was assessed using Western blot, extra-long polymerase chain reaction, reactive oxygen species production, and immunofluorescence. Autophagy and modulation of the Hippo signaling pathway were investigated using proteomics, Western blot, immunofluorescence, and reverse-transcription quantitative polymerase chain reaction.

RESULTS

In both 2- and 3-dimensional settings, PR cells were more sensitive to IR and showed decreased β-globin amplification, indicating more DNA damage accumulation compared with GR or wild-type cells after 24 hours. Proteomic analysis of PR PATU-T cells revealed that the protein MST4, a kinase involved in autophagy and the Hippo signaling pathway, was highly downregulated. A differential association was found between autophagy and radiation treatment depending on the cell model. Interestingly, increased yes-associated protein nuclear localization and downstream Hippo signaling pathway target gene expression were observed in response to IR.

CONCLUSIONS

This was the first study investigating the potential of IR in targeting PDAC cells with acquired chemoresistance. Our results demonstrate that PR cells exhibit enhanced sensitivity to IR due to greater accumulation of DNA damage. Additionally, depending on the specific cellular context, radiation-induced modulation of autophagy and the Hippo signaling pathway emerged as potential underlying mechanisms, findings with potential to inform personalized treatment strategies for patients with acquired chemoresistance.

An Adaptable Nanoprobe Integrated with Quantitative T1 -Mapping MRI for Accurate Differential Diagnosis of Multidrug-Resistant Lung Cancer

Multidrug resistance (MDR) is one of the major factors causing failure of non-small-cell lung cancer (NSCLC) chemotherapy. Real-time and accurate differentiation between drug-resistant and sensitive NSCLC is of primary importance for guiding the subsequent treatments and improving the therapeutic outcome. However, there is no effective method to provide such an accurate differentiation. This study creates an innovative strategy of integrating H2 O2 -responsive nanoprobes with the quantitative T1 -mapping magnetic resonance imaging (MRI) technique to achieve an accurate differential diagnosis between drug-resistant and sensitive NSCLC in light of differences in H2 O2 content in the tumor microenvironment (TME). The result demonstrates that the synthesized MIL-53(Fe)@MnO2 nanocomposites possess an excellent capability of shortening the cancer longitudinal relaxation time (T1 ) when meeting H2 O2 in TME. T1 -mapping MRI could sensitively detect this T1 variation (about 2.6-fold that of T1-weighted imaging (T1 WI)) to accurately differentiate the H2 O2 content between drug-resistant and sensitive NSCLC. In addition, the quantitative data provided by the T1 -mapping MRI dedicates correct comparison across imaging tests and is more reliable than T1 WI, thus giving it a chance for precise assessment of the anti-cancer effect. This innovative strategy of merging TME adaptable nanoprobes with the quantitative MRI technique provides a new approach for the precise diagnosis of multidrug-resistant NSCLC.

Chitosan-encapsulated naringenin promotes ROS mediated through the activation of executioner caspase-3

We previously reported that chitosan nanoparticle-encapsulated Naringenin (CS-NPs/NAR) could scavenge free radicals at lower doses and be cytotoxic to cancer cells. The current study continues to focus on the mechanism behind CS-NPs/NAR-induced breast cancer cell (MDA-MB-231) death. MDA-MB-231 cells were treated with higher concentrations (100, 200, and 200 µg) of Chitosan nanoparticles (CS-NPs), naringenin (NAR), and chitosan-encapsulated naringenin (CS-NPs/NAR). The cell viability, proliferation, and oxidative stress parameters, such as nitric oxide [NO], xanthine oxidase (XOD), and xanthine dehydrogenase (XDH) levels, were analyzed. ROS levels were determined through DCFDA analysis. MTT-based cell cytotoxicity and BrdU cell proliferation analysis depicted the cytotoxicity effects (37% and 29% for 24 and 48 h) and exhibited a reduction in the proliferation of MDA-MB-231 by CS-NPs/NAR. A significant increase in NO content, XOD, a decrease in XDH, and an increase in ROS levels were observed upon treatment with CS-NPs/NAR. Fluorescent images suggested the increase in the ROS level upon treatment with CS-NPs/NAR in cancer cells, and the results suggested that it could induce apoptosis. Further, to confirm this, the activity of caspase-3 was analyzed through western blotting, and the result suggested that the higher concentration of CS-NPs/NAR has increased the activation of procaspase3 when compared to free NAR. Hence, the current investigation concludes that high doses of CS-NPs/NAR induce and increase oxidative stress and so increased activation of procaspase3 may lead to cancer cell apoptosis and reduction in cell proliferation.

Autophagy in cancer resistance to paclitaxel: Development of combination strategies

Paclitaxel, a compound naturally occurring in yew, is a commonly used drug for the treatment of different types of cancer. Unfortunately, frequent cancer cell resistance significantly decreases its anticancer effectivity. The main reason for the resistance development is the paclitaxel-induced phenomenon of cytoprotective autophagy occurring by different mechanisms of action in dependence on a cell type and possibly even leading to metastases. Paclitaxel also induces autophagy in cancer stem cells, which greatly contributes to tumor resistance development. Paclitaxel anticancer effectivity can be predicted by the presence of several autophagy-related molecular markers, such as tumor necrosis factor superfamily member 13 in triple-negative breast cancer or cystine/glutamate transporter encoded by the SLC7A11 gene in ovarian cancer. Nevertheless, the undesired effects of paclitaxel-induced autophagy can be eliminated by paclitaxel co-administration with autophagy inhibitors, such as chloroquine. Interestingly, in certain cases, it is worthy of potentiating autophagy by paclitaxel combination with autophagy inducers, for instance, apatinib. A modern strategy in anticancer research is also to encapsulate chemotherapeutics into nanoparticle carriers or develop their novel derivatives with improved anticancer properties. Hence, in this review article, we summarize not only the current knowledge of paclitaxel-induced autophagy and its role in cancer resistance but mainly the possible drug combinations based on paclitaxel and their administration in nanoparticle-based formulations as well as paclitaxel analogs with autophagy-modulating properties.

Azithromycin Protects Retinal Glia Against Oxidative Stress-Induced Morphological Changes, Inflammation, and Cell Death

The reactivity of retinal glia in response to oxidative stress has a significant effect on retinal pathobiology. The reactive glia change their morphology and secret cytokines and neurotoxic factors in response to oxidative stress associated with retinal neurovascular degeneration. Therefore, pharmacological intervention to protect glial health against oxidative stress is crucial for maintaining homeostasis and the normal function of the retina. In this study, we explored the effect of azithromycin, a macrolide antibiotic with antioxidant, immunomodulatory, anti-inflammatory, and neuroprotective properties against oxidative stress-induced morphological changes, inflammation, and cell death in retinal microglia and Müller glia. Oxidative stress was induced by H₂O₂, and the intracellular oxidative stress was measured by DCFDA and DHE staining. The change in morphological characteristics such as the surface area, perimeter, and circularity was calculated using ImageJ software. Inflammation was measured by enzyme-linked immunosorbent assays for TNF-α, IL-1β, and IL-6. Reactive gliosis was characterized by anti-GFAP immunostaining. Cell death was measured by MTT assay, acridine orange/propidium iodide, and trypan blue staining. Pretreatment of azithromycin inhibits H₂O₂-induced oxidative stress in microglial (BV-2) and Müller glial (MIO-M1) cells. We observed that azithromycin inhibits oxidative stress-induced morphological changes, including the cell surface area, circularity, and perimeter in BV-2 and MIO-M1 cells. It also inhibits inflammation and cell death in both the glial cells. Azithromycin could be used as a pharmacological intervention on maintaining retinal glial health during oxidative stress.

Acquisition of paclitaxel resistance modulates the biological traits of gastric cancer AGS cells and facilitates epithelial to mesenchymal transition and angiogenesis

PURPOSE

This study aims to develop a paclitaxel (PTX)-resistant gastric cancer AGS cells (AGS-R) and evaluate the mechanisms of drug resistance.

METHODS

AGS cells were successively treated with increasing PTX concentrations. Cross-resistance of established AGS-R, the molecular patterns of cell survival, evasion of apoptosis, epithelial-mesenchymal transition (EMT), and the angiogenic potential were evaluated.

RESULTS

AGS-R was induced within six months of PTX exposure. Extension of the treatment resulted in PTX-resistance beyond clinical levels. The established AGS-R showed resistance to vincristine and doxorubicin but not cisplatin. Upon induction of resistance, the expressions of MDR-1 (P < 0.001) and MRP-1 (P < 0.01) genes and proteins significantly increased. AGS-R cells had elevated levels of BCL-2, pro-CASP3, cleaved-NOTCH1, HES1, HEY1, NF-κB, PI3K, p-AKT, HIF-1α, Cyclin A, and B1 as compared with parental cells (at least P < 0.01). The protein levels of BAX, CASP3, P53, and P21 (at least P < 0.01) as well as intracellular ROS (P < 0.001) were reduced in AGS-R. A relative arrest at the G2/M phase (15.8 ± 0.75 vs. 26.7 ± 1.67) of the cell cycle and enrichment of AGS-R cells for CD44 marker (9 ± 0.6 vs. 1 ± 0.8) (P < 0.001) were detected by flow cytometry. While the E-cadherin expression was reduced (P < 0.001), the protein levels of Vimentin, N-cadherin, SLUG, and SNAIL were increased (at least P < 0.05). The angiogenic activity and release of VEGF and MMP2/9 were increased in AGS-R cells relative to the AGS line (P < 0.001).

CONCLUSION

AGS-R cells could bypass chemotherapy stress by expressing the genes coding for efflux pumps and altering some key signaling in favor of survival, EMT, and angiogenesis.

Paclitaxel Resistance Modulated by the Interaction between TRPS1 and AF178030.2 in Triple-Negative Breast Cancer

Paclitaxel is a chemotherapeutic agent that acts as an inhibitor of cellular mitosis and has been widely used in the treatment of triple-negative breast cancer (TNBC). However, paclitaxel resistance is one of the major reasons that contribute to the high failure rates of chemotherapy and the relapse of TNBC. Accumulating studies have demonstrated that long noncoding RNA (lncRNA) plays a role in the paclitaxel resistance and positively correlated with progression and metastasis of breast cancers. In the present study, microarray expression profile analysis of lncRNA was performed between paclitaxel-resistant TNBC cell line MDA-MB-231 and their parental cells. After verification with quantitative PCR, we identified that AF178030.2, an orphan lncRNA, was significantly upregulated in paclitaxel-resistant TNBC cells. Overexpression of AF178030.2 greatly attenuated the sensitivity of TNBC to paclitaxel, whereas knockdown of AF178030.2 enhanced the sensitivity of TNBC cells to paclitaxel. Furthermore, bioinformatic analysis and RNA binding protein immunoprecipitation assay reveal that AF178030.2 can directly bind with trichorhinophalangeal syndrome-1 (TRPS1), an oncogene in breast cancer, and downregulate its expression in paclitaxel-resistant TNBC cells. TRPS1 overexpression effectively increased the sensitivity of paclitaxel-resistant TNBC cells to paclitaxel. Taking together, high AF178030.2 expression contributed to paclitaxel resistance in TNBC through TRPS1 and poor clinical outcomes, which may provide a new treatment strategy for paclitaxel-resistant TNBC patients.

Caryophyllene Oxide, the Active Compound Isolated from Leaves of Hymenaea courbaril L. (Fabaceae) with Antiproliferative and Apoptotic Effects on PC-3 Androgen-Independent Prostate Cancer Cell Line

Cancer treatment frequently carries side effects, therefore, the search for new selective and effective molecules is indispensable. Hymenaea courbaril L. has been used in traditional medicine in South America to treat several diseases, including prostate cancer. Leaves’ extracts from different polarities were evaluated using the 3-(4,5-methyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) cell viability assay to determine the cytotoxicity in prostate p53-null cells, followed by bio-guided fractionations to obtain the most cytotoxic fraction considering the selectivity index. The most cytotoxic fraction was analyzed by GC/MS to identify the active compounds. The majority compound, caryophyllene oxide, induced early and late apoptosis, depolarized the mitochondrial membrane, leading to several morphological changes and shifts in apoptotic proteins, and caspases were evidenced. Depolarization of the mitochondrial membrane releases the pro-apoptotic protein Bax from Bcl-xL. The apoptosis process is caspase-7 activation-dependent. Caryophyllene oxide is a safe anti-proliferative agent against PC-3 cells, inducing apoptosis with low toxicity towards normal cells.

A novel design of microfluidic platform for metronomic combinatorial chemotherapy drug screening based on 3D tumor spheroid model

For treating cancer at various stages, chemotherapy drugs administered in combination provide better treatment results with lower side effects compared to single-drug therapy. However, finding the potential drug combinations has been challenging due to the large numbers of possible combinations from approved drugs and the failure of in vitro 2D well plate-based cancer models. 3D spheroid-based high-throughput microfluidic platforms recapitulate some of the important features of native tumor tissue and offer a promising alternative to evaluate the combinatory effects of the drugs. This study develops a novel polydimethylsiloxane (PDMS) based microfluidic design with a dynamic environment and strategically placed U-shaped wells for testing all seven possible combinations (three single-drug treatments, three pairwise combinations, treatment with all three drugs) of three chemotherapy drugs (Paclitaxel, Vinorelbine, and Etoposide) on lung tumor spheroids. The design of U-shaped wells has been validated with computational results. Firstly, we test all combinations of drugs on the conventional well plate in static conditions with 3D tumor spheroids. Based on static drug testing results, we show a proof-of-concept by testing the most effective drug combination on the microfluidic device in a dynamic environment. The concentration of the drugs used in combination falls below the maximum tolerated dose (MTD) of the individual drugs, towards low dose metronomic (LDM) chemotherapy. LDM combinatorial chemotherapy identified in this study can potentially lower toxicity and provide better treatment results in cancer patients. The device can be further used to culture patient-specific tumor spheroids and identify synergistic drug combinations for personalized medicine.

Nanotherapeutic approaches to target mitochondria in cancer

Treatment of cancer cells exemplifies a difficult test in the light of challenges associated with the nature of cancer cells and the severe side effects too. After making a large number of trials using both traditional and advanced therapies (immunotherapy and hormone therapy), approaches to design new therapies have reached a saturation level. However, nanotechnology-based approaches exhibit higher efficacy and great potential to bypass many of such therapeutic limitations. Because of their higher target specificity, the use of nanoparticles offers incredible potential in cancer therapeutics. Mitochondria, acting as a factory of energy production in cells, reveal an important role in the death as well as the survival of cells. Because of its significant involvement in the proliferation of cancer cells, it is being regarded as an important target for cancer therapeutics. Numerous studies reveal that nanotechnology-based approaches to directly target the mitochondria may help in improving the survival rate of cancer patients. In the current study, we have detailed the significance of mitochondria in the development of cancer phenotype, as well as indicated it as the potential targets for cancer therapy. Our study further highlights the importance of different nanoparticle-based approaches to target mitochondria of cancer cells and the associated outcomes of different studies. Though, nanotechnology-based approaches to target mitochondria of cancer cells demonstrate a potential and efficient way in cancer therapeutics. Yet, further study is needed to overcome the linked limitations.

Platinum drugs and taxanes: can we overcome resistance?

Cancer therapy is aimed at the elimination of tumor cells and acts via the cessation of cell proliferation and induction of cell death. Many research publications discussing the mechanisms of anticancer drugs use the terms "cell death" and "apoptosis" interchangeably, given that apoptotic pathways are the most common components of the action of targeted and cytotoxic compounds. However, there is sound evidence suggesting that other mechanisms of drug-induced cell death, such as necroptosis, ferroptosis, autophagy, etc. may significantly contribute to the fate of cancer cells. Molecular cross-talks between apoptotic and nonapoptotic death pathways underlie the successes and the failures of therapeutic interventions. Here we discuss the nuances of the antitumor action of two groups of the widely used anticancer drugs, i.e., platinum salts and taxane derivatives. The available data suggest that intelligent interference with the choice of cell death pathways may open novel opportunities for cancer treatment.

Extra- and Intracellular Monitoring of TGF-β Using Single Immunoplasmonic Nanoprobes

Transforming growth factor-β (TGF-β) is a well-known disease-related biomarker associated with fibrotic diseases, and initiation and progression of cancer in many organs. Therefore, quantitative and sensitive detection of TGF-β and similar biomarkers is crucial for patient treatment in the early stages of diagnosis. In many studies, the detection of TGF-β, an important profibrotic and cancer promoting cytokine, has been generally conducted by fluorescence or absorbance-based immunoassays. However, conventional methods for detecting TGF-β have problems including use of time-consuming sample pretreatment steps and multiple reagents for signal amplification and difficulty in real-time detection from living cells. Herein, we present a plasmon-based immunoassay for TGF-β using antibody-conjugated single gold nanoparticles that act as optically excellent intracellular and extracellular detection probes that do not require additional signal amplification. To detect TGF-β sensitively and selectively, we exploited the localized surface plasmon resonance (LSPR) property of antibody-conjugated plasmonic gold nanoparticles at a single particle level. By measuring the LSPR spectral shifts of the single plasmonic nanoprobes, TGF-β can be detected down to the picomolar level, which is comparable with the conventional methods but without significant interference from other proteins. The optimized plasmonic nanoprobes were applied to quantify and monitor the extracellular TGF-β level secreted from the cells under stress conditions, such as cancer, and exposure to toxic environments. Owing to the ease of cellular internalization of the nanoprobes, we directly image and detect increases in intracellular TGF-β levels in living cells under the given stress conditions without cell lysis. We envision that this strategy of using individual nanoparticles as sensors to monitor protein biomarkers in living cells could be applied for various biological assays and diagnosis.

Functionality of receptor targeted zinc-insulin quantum clusters in skin tissue augmentation and bioimaging

Quantum clusters with target specificity are suitable for tissue-specific imaging. In the present work, amorphous zinc insulin quantum clusters (IZnQCs) had been synthesised to promote and monitor wound recovery. Easy synthesis, biocompatibility, stability, enhanced quantum yield, and solubility made the cluster suitable for preclinical/clinical exploration. Zn²⁺ is known for its binding to insulin hexamer. Here we report the reformation of the structure in a quantum cluster form in the presence of Zn²⁺. The formation of IZnQCs was confirmed by the change in zeta potential from -25.6 mV to -17.9 mV and also the formation of protein metal interaction was confirmed in FTIR bands at 450, 480, and 613 cm^-1 for Zn-O, Zn-N, and Zn-S, respectively. HRTEM-EDS and SAED data analysis showed an amorphous nature of the cluster. The binding of IZnQCs to the cells has been confirmed using confocal microscopy. IZnQCs showed a synergistic effect in wound recovery than insulin or Zn²⁺ alone. Further due to high fluorescence this recovery process can be monitored under an appropriate setup. Wound healing promotional activity, target specificity, and fluorescence properties make the IZnQCs ideal to use for bioimaging along with promoting and monitoring of wound recovery agent.

Biomedical Evaluation of Lansium parasiticum Extract-Protected Silver Nanoparticles Against Haemonchus contortus, a Parasitic Worm

Here we show the novel anti-helminthic potential of Lansium parasiticum aqueous extract-protected silver nanoparticles (LAgNPs) against albendazole-resistant gastrointestinal parasite Haemonchus contortus. LAgNPs showed LD₅₀ values of 65.6 ± 32.8 nM (12 h), 139.6 ± 39.9 nM (12 h), and 64.3 ± 8.5 nM (24 h) against adult male, female, and L3 larvae, respectively. LAgNPs was also quite effective in inhibiting egg hatching, with an IC₅₀ value of 144.4 ± 3.1 nM at 48 h of exposure. Exposure to LAgNPs generated oxidative stress and mediated physical damage in the worms' tissue. A sharp increase in reactive oxygen species and nitric oxide synthase levels was prominent due to LAgNPs' exposure. In response to oxidative stress, a sharp increase of stress-responsive enzymes' activity, like catalase, superoxide dismutase, and glutathione peroxidase activity, along with the concentration of glutathione, was observed in worm tissue, which indicated a LAgNP-responsive alteration of metabolism. The results give rise to the opportunity for the development of alternative treatment for drug-resistant parasitic worms.

Mechanisms of docetaxel resistance in prostate cancer: The key role played by miRNAs

One of the main problems with the treatment of metastatic prostate cancer is that, despite an initial positive response, the majority of patients develop resistance and progress. In particular, the resistance to docetaxel, the gold standard therapy for metastatic prostate cancer since 2010, represents one of the main factors responsible for the failure of prostate cancer therapy. According to the present knowledge, different processes contribute to the appearance of docetaxel resistance and non-coding RNA seems to play a relevant role in them. In this review, a comprehensive overview of the miRNA network involved in docetaxel resistance is described, highlighting the pathway/s affected by their activity.

Cuminaldehyde induces oxidative stress-mediated physical damage and death of Haemonchus contortus

Cuminaldehyde (CA), a monoterpenoid, preset in many plant sources including cumin, induces reactive oxygen-related damage and death in Haemonchus contortus, a parasitic worm with an LD50, values of 127.3 ± 7.5, 184.5 ± 12.1 and 104.1 ± 7.9 μg/mL for an adult female, adult male worms (12 h) and L3 larvae, respectively (24 h). Fifty percent of inhibition of egg hatching (IC50) was obtained at 142.4 ± 11.4 μg/mL after 48 h of exposure. Scanning electron microscopy revealed physical damage to the anterior and posterior ends, intestinal, ovarian, and esophageal regions of the warms on exposure to ca. The exposure of worms to CA also led to a systemic increase in reactive oxygen species (ROS) within 3 h. The better activity was seen with CA compared to standard antihelminthic drug albendazole (Alb). 74 μg/mL CA showed 2.3 fold more increase of catalase (CAT), 0.61 fold increase of superoxide dismutase (SOD), 3.3 fold increase of glutathione peroxidase (GPx) activity and 17.5 fold increase of glutathione (GSH) activity in comparison with Alb (500 μg/mL) for the same time of exposure (3 h). A firm increase of (2.9 fold) was also observed in nitric oxide synthase (NOS) activity within 12 h of exposure with CA (74 μg/mL) in comparison with Alb. Therefore the preclinical potential of CA is much higher than widely used antihelminthic drug Alb. The results open new opportunities to explore CA as a new active antihelminthic molecule.

Low dose HSP90 inhibition with AUY922 blunts rapid evolution of metastatic and drug resistant phenotypes induced by TGF-β and paclitaxel in A549 cells

OBJECTIVES

Despite advances in cancer treatment, drug resistance and metastasis continue to contribute to treatment failure. Since drug resistance and metastasis in cancer are features that often occur toward the late stages in the disease after withstanding numerous selective pressures, they may rely on a shared adaptive mechanism in order to persist. The heat shock response is one of the most well conserved adaptive responses to cellular stress found in nature. A major player in the heat shock response is HSP90, with some studies suggesting that it can facilitate the molecular evolution of drug resistance and metastasis in cancer. Non-small cell lung cancers (NSCLCs) are strongly associated with drug resistance and metastasis either at the time of diagnosis or early in the treatment process.

MATERIALS AND METHODS

We explored the role of HSP90 in the evolution of metastatic and drug resistant features in NSCLC by treating A549 cells with AUY922, a clinically relevant HSP90 inhibitor, and inducing metastatic and drug resistant phenotypes via treatment with TGF-β and paclitaxel, respectively. We measured phenotypic plasticity in E-Cadherin, a marker for epithelial to mesenchymal transition and two ABC transporters associated with drug resistant lung cancers.

RESULTS

We found that metastatic and efflux dependent drug resistant features negatively correlated with AUY922 treatment. We followed our results with functional assays relevant to metastasis and ABC transporters to confirm our results. Specifically we found the expression of E-cadherin was significantly increased in A549 cultures pretreated with AUY922 prior to exposure to paclitaxel, while expression of the drug transporters ABCB1 and ABCC1 was significantly reduced under similar conditions.

CONCLUSION

Together our data indicates that HSP90 inhibition with AUY922 can limit the acquisition of metastatic and drug resistant phenotypes in A549 cells at low, clinically appropriate doses.

Herbometallic nano-drug inducing metastatic growth inhibition in breast cancer through intracellular energy depletion

Cancer cells need extensive energy supply for their uncontrolled cell division and metastasis which is exclusively dependent on neighboring cells, especially adipocytes. Herein, we have introduced a novel herbometallic nano-drug, Heerak Bhasma nanoparticle (HBNP) from natural resources showing high potential in the reduction of energy supply thereby promoting cell death in breast cancer cells. Inductively coupled plasma optical emission spectra (ICP-OES), atomic absorption spectra (AAS), Raman spectra, X-ray diffraction analyses confirmed the physicochemical properties of HBNP. The differential light scattering (DLS) and field emission scanning electron microscope (FESEM) analyzed the cell-permeable size of HBNP, whereas, cell viability assay confirmed the non-toxic effect. Seahorse energy efflux assay, apoptotic cell quantification, ROS, mitochondrial membrane potential, in vivo oxidative stress etc. were measured using standard protocol. The notable changes in cancer energy metabolism investigated by cellular Mito and Glyco-stress analyses confirmed the HBNP induced intracellular energy depletion. Also, a significant reduction in mitochondrial membrane potential and subsequently, extensive reactive oxygen species (ROS) generations were observed in presence of HBNP followed by the induction of cell apoptosis. The cell invasion and wound healing assay followed by reduced expression both protein (MMP 2, MMP 9) and cytokine (IL6, IL10) had signified the effectiveness of HBNP against cancer metastasis. In addition, HBNP also showed an excellent antitumor activity in vivo followed by developing healing characteristics due to oxidative stress. All these findings strongly suggest that HBNP has the potential to be the new cancer therapeutic. A schematic phenomenon represents the overall HBNP mediated anticancer activity via limitation of both fatty acid uptake and energy metabolism.

ATG5 knockout promotes paclitaxel sensitivity in drug-resistant cells via induction of necrotic cell death

Autophagy regulators are often effective as potential cancer therapeutic agents. Here, we investigated paclitaxel sensitivity in cells with knockout (KO) of ATG5 gene. The ATG5 KO in multidrug resistant v-Ha-ras-transformed NIH 3T3 cells (Ras-NIH 3T3/Mdr) was generated using the CRISPR/Cas9 technology. The qPCR and LC3 immunoblot confirmed knockout of the gene and protein of ATG5, respectively. The ATG5 KO restored the sensitivity of Ras-NIH 3T3/Mdr cells to paclitaxel. Interestingly, ATG5 overexpression restored autophagy function in ATG5 KO cells, but failed to rescue paclitaxel resistance. These results raise the possibility that low level of resistance to paclitaxel in ATG5 KO cells may be related to other roles of ATG5 independent of its function in autophagy. The ATG5 KO significantly induced a G2/M arrest in cell cycle progression. Additionally, ATG5 KO caused necrosis of a high proportion of cells after paclitaxel treatment. These data suggest that the difference in sensitivity to paclitaxel between ATG5 KO and their parental MDR cells may result from the disparity in the proportions of necrotic cells in both populations. Thus, our results demonstrate that the ATG5 KO in paclitaxel resistant cells leads to a marked G2/M arrest and sensitizes cells to paclitaxel-induced necrosis.

Exploiting Cancer Cells Metabolic Adaptability to Enhance Therapy Response in Cancer

Despite all the progresses developed in prevention and new treatment approaches, cancer is the second leading cause of death worldwide, being chemoresistance a pivotal barrier in cancer management. Cancer cells present several mechanisms of drug resistance/tolerance and recently, growing evidence have been supporting a role of metabolism reprograming per se as a driver of chemoresistance. In fact, cancer cells display several adaptive mechanisms that allow the emergency of chemoresistance, revealing cancer as a disease that adapts and evolve along with the treatment. Therefore, clinical protocols that take into account the adaptive potential of cancer cells should be more effective than the current traditional standard protocols on the fighting against cancer.In here, some of the recent findings on the role of metabolism reprograming in cancer chemoresistance emergence will be discussed, as the potential evolutionary strategies that could unable these adaptations, hence allowing to prevent the emergency of treatment resistance, changing cancer outcome.

Cellular Interactome Dynamics during Paclitaxel Treatment

Cell-cycle inhibitors, including paclitaxel, are among the most widely used and effective cancer therapies. However, several challenges limit the success of paclitaxel, including drug resistance and toxic side effects. Paclitaxel is thought to act primarily by stabilizing microtubules, locking cells in a mitotic state. However, the resulting cytotoxicity and tumor shrinkage rates observed cannot be fully explained by this mechanism alone. Here we apply quantitative chemical cross-linking with mass spectrometry analysis to paclitaxel-treated cells. Our results provide large-scale measurements of relative protein levels and, perhaps more importantly, changes to protein conformations and interactions that occur upon paclitaxel treatment. Drug concentration-dependent changes are revealed in known drug targets including tubulins, as well as many other proteins and protein complexes involved in apoptotic signaling and cellular homeostasis. As such, this study provides insight into systems-level changes to protein structures and interactions that occur with paclitaxel treatment.

Long non-coding RNA ENST00000500843 is downregulated and promotes chemoresistance to paclitaxel in lung adenocarcinoma

Adenocarcinoma is one of the most common pathological types of human lung cancer and has the highest incidence and mortality rates worldwide. Resistance to paclitaxel (PTX), the standard chemotherapy agent for treatment of lung adenocarcinoma, is a major clinical obstacle. Sensitive markers are urgently required for the diagnosis and characterization of lung cancer, as well as to manage drug resistance. Previous studies have described the activity of long non-coding RNAs (lncRNAs) in human lung cancer and chemotherapy resistance. In previous studies, lncRNA ENST00000500843 was identified to be downregulated in PTX-resistant A549 human lung cancer cells. However, the roles of this lncRNA in the development of lung adenocarcinoma and its mechanism in PTX resistance, to the best of our knowledge, have not been described. In the present study, 56 pairs of lung adenocarcinoma and normal adjacent tissue samples were collected. Reverse transcription-quantitative PCR revealed that the expression levels of lncRNA ENST00000500843 were lower in lung adenocarcinoma tissues and PTX-resistant A549 cells when compared with normal adjacent tissues and A549 cells. Decreased expression levels of lncRNA ENST00000500843 in lung adenocarcinoma tissues were associated with tumor diameter, the degree of pathological differentiation and metastasis of lymph nodes. Additionally, patients with low expression levels of ENST00000500843 exhibited poorer overall survival and progression-free survival rates. Furthermore, the present study demonstrated that knockdown of lncRNA ENST00000500843 with small interfering RNA decreased the likelihood of apoptosis in A549 cells and promoted resistance to PTX. This indicated that lncRNA ENST00000500843 may be a useful diagnostic marker of lung cancer and a good prognostic marker for resistance to treatment with PTX.

Paclitaxel-encapsulated core–shell nanoparticle of cetyl alcohol for active targeted delivery through oral route

Aim: Paclitaxel (PTX) has no clinically available oral formulations. Cetyl alcohol is metabolized by alcohol dehydrogenase and aldehyde dehydrogenase that are overexpressed in cancer cells. So, PTX-encapsulated core–shell nanoparticle of cetyl alcohol (PaxSLN) could target the cancer cells through oral route. Materials & methods: PaxSLN was synthesized using microemulsion template. Efficiency of PaxSLN was evaluated by ALDEFLUOR™, multicellular tumor spheroid formation inhibition assays and CT26 colorectal carcinoma animal model. Pharmacokinetics and biodistribution studies were done in Sprague Dawley rats. Results: PTX was encapsulated at the core of approximately 78 nm PaxSLN. PaxSLN targeted aldehyde dehydrogenase overexpressing cells. Its oral bioavailability was approximately 95% and chemotherapeutic efficacy was better than Taxol® and nab-PTX. Conclusion: A novel oral nanoformulation of PTX was developed.

Essential roles of mitochondrial and heme function in lung cancer bioenergetics and tumorigenesis

Contrary to Warburg’s hypothesis, mitochondrial oxidative phosphorylation (OXPHOS) contributes significantly to fueling cancer cells. Several recent studies have demonstrated that radiotherapy-resistant and chemotherapy-resistant cancer cells depend on OXPHOS for survival and progression. Several cancers exhibit an increased risk in association with heme intake. Mitochondria are widely known to carry out oxidative phosphorylation. In addition, mitochondria are also involved in heme synthesis. Heme serves as a prosthetic group for several proteins that constitute the complexes of mitochondrial electron transport chain. Therefore, heme plays a pivotal role in OXPHOS and oxygen consumption. Further, lung cancer cells exhibit heme accumulation and require heme for proliferation and invasion in vitro. Abnormalities in mitochondrial biogenesis and mutations are implicated in cancer. This review delves into mitochondrial OXPHOS and lesser explored area of heme metabolism in lung cancer.

Hypoxia and Noncoding RNAs in Taxane Resistance

Taxanes are chemotherapeutic drugs employed in the clinic to treat a variety of malignancies. Despite their overall efficacy, cancer cells often display resistance to taxanes. Therefore, new strategies to increase the effectiveness of taxane-based chemotherapeutics are urgently needed. Multiple molecular players are linked to taxane resistance; these include efflux pumps, DNA repair mechanisms, and hypoxia-related pathways. In addition, emerging evidence indicates that both non-coding RNAs and epigenetic effectors might also be implicated in taxane resistance. Here we focus on the causes of taxane resistance, with the aim to envisage an integrated model of the 'taxane resistance phenome'. This model could help the development of novel therapeutic strategies to treat taxane-resistant neoplasms.

Overcoming resistance to mitochondrial apoptosis by BZML-induced mitotic catastrophe is enhanced by inhibition of autophagy in A549/Taxol cells

OBJECTIVES

Our previous in vitro study showed that 5-(3, 4, 5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl) imidazol (BZML) is a novel colchicine binding site inhibitor with potent anti-cancer activity against apoptosis resistance in A549/Taxol cells through mitotic catastrophe (MC). However, the mechanisms underlying apoptosis resistance in A549/Taxol cells remain unknown. To clarify these mechanisms, in the present study, we investigated the molecular mechanisms of apoptosis and autophagy, which are closely associated with MC in BZML-treated A549 and A549/Taxol cells.

METHODS

Xenograft NSCLC models induced by A549 and A549/Taxol cells were used to evaluate the efficacy of BZML in vivo. The activation of the mitochondrial apoptotic pathway was assessed using JC-1 staining, Annexin V-FITC/PI double-staining, a caspase-9 fluorescence metric assay kit and western blot. The different functional forms of autophagy were distinguished by determining the impact of autophagy inhibition on drug sensitivity.

RESULTS

Our data showed that BZML also exhibited desirable anti-cancer activity against drug-resistant NSCLC in vivo. Moreover, BZML caused ROS generation and MMP loss followed by the release of cytochrome c from mitochondria to cytosol in both A549 and A549/Taxol cells. However, the ROS-mediated apoptotic pathway involving the mitochondria that is induced by BZML was only fully activated in A549 cells but not in A549/Taxol cells. Importantly, we found that autophagy acted as a non-protective type of autophagy during BZML-induced apoptosis in A549 cells, whereas it acted as a type of cytoprotective autophagy against BZML-induced MC in A549/Taxol cells.

CONCLUSIONS

Our data suggest that the anti-apoptosis property of A549/Taxol cells originates from a defect in activation of the mitochondrial apoptotic pathway, and autophagy inhibitors can potentiate BZML-induced MC to overcome resistance to mitochondrial apoptosis.