Schisandrin B Suppresses Colon Cancer Growth by Inducing Cell Cycle Arrest and Apoptosis: Molecular Mechanism and Therapeutic Potential.

Colon cancer is among the most lethal and prevalent malignant tumors in the world, and the lack of effective therapies highlights the need for novel therapeutic approaches. Schisandrin B (Sch B), a lignan extracted from the fruit ofSchisandra chinensis, has been reported for its anticancer properties. However, to date, no studies have been done to characterize the exact molecular mechanisms underlying the antitumorigenic effects of Sch B in colon cancer. This study aimed to explore the antitumorigenic effects of Sch B in colon cancer and to understand the underlying therapeutic mechanism. A comprehensive analysis of the molecular mechanism underlying the antitumorigenic effects of Sch B on human colon cancer cells was performed using a combination of Raman spectroscopy, RNA-seq, computational docking, and molecular biological experiments. The in vivo efficacy was evaluated by a mouse xenograft model. Sch B reduced cell proliferation and triggered apoptosis in human colon cancer cell lines. Raman spectroscopy, computational, RNA-seq, and molecular and cellular studies revealed that Sch B activated unfolded protein responses by interacting with CHOP and upregulating CHOP, which thereby induced apoptosis. CHOP knockdown alleviated the Sch B-induced reduction in cell viability and apoptosis. Sch B reduced colon tumor growth in vivo. Our findings demonstrated that Sch B induced apoptosis and inhibited cell proliferation and tumor growth in vitro and in vivo. These results provided an essential background for clinical trials examining the effects of Sch B in patients with colon cancer.

Enhanced chemotherapeutic efficacy of docetaxel in human lung cancer cell line via GLUT1 inhibitor.

The dose-dependent adverse effects of anticancer agents need new methods with lesser toxicity. The objective of the current research was to evaluate the efficacy of GLUT1 inhibitor, as an inhibitor of glucose consumption in cancer cells, in augmenting the efficiency of docetaxel with respect to cytotoxicity and apoptosis. Cell cytotoxicity was assessed by using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. Annexin V/PI double staining was employed to evaluate apoptosis percentage. Quantitative real-time polymerase chain reaction (RT-PCR) analysis was accomplished to detect the expression of genes involved in the apoptosis pathway. The IC50 values for docetaxel and BAY-876 were 3.7 ± 0.81 and 34.1 ± 3.4 nM, respectively. The severity of synergistic mutual effects of these agents on each other was calculated by synergy finder application. It showed that the percentage of apoptotic cells following co-administration of docetaxel and BAY-876 increased to 48.1 ± 2.8%. In comparison without GLUT1 co-administration, the combined therapy decreased significantly the transcriptome levels of the Bcl-2 and Ki-67 and a remarkable increase in the level of the Bax as proapoptotic protein(p < 0.05). Co-treatment of BAY-876 and docetaxel depicted a synergistic effect which was calculated using the synergy finder highest single agent (HSA) method (HSA synergy score: 28.055). These findings recommend that the combination of GLUT-1 inhibitor and docetaxel can be considered as a promising therapeutic approach for the treatment of patients with lung cancer.

Blockade of TGF-ßR improves the efficacy of doxorubicin by modulating the tumor cell motility and affecting the immune cells in a melanoma model.

TGF-ß contributes to drug resistance and the invasiveness of tumor cells and weakens the anti-tumor immune responses. The present study aimed at examining the efficacy of the combination of SB431542, as a specific inhibitor of TGF-ßR, and doxorubicin in controlling the melanoma tumor in mice. The impact of the combination of the doxorubicin and SB431542 on the cell growth, apoptosis, migration, and invasiveness of B16-F10 cells was examined. Besides, the B16-F10 tumor was induced in C57BL/6 mice, and the effects of the mentioned treatment on the tumor volume, survival, and the exhaustion state of T cells were evaluated. Although the combination of doxorubicin and SB431542 did not exhibit synergism in the inhibition of cell growth and apoptosis induction, it efficiently prohibited the migration and the epithelial to mesenchymal transition of B16-F10 cells, and the combination of doxorubicin and SB431542 caused an increase in mRNA levels of E-cadherin and, on the other hand, led to a decline in the expression of Vimentin. Tumor volume and the survival of tumor-bearing mice were efficiently controlled by the combination therapy. This treatment also eventuated in a decrease in the percentage of PD-L1+, TCD4+, and TCD8+ cells as indicators of exhausted T cells within the spleens of tumor-bearing mice. Blockade of TGF-ßR also propelled the RAW 264.7 cells towards an anti-tumor M1 macrophage phenotype. The inhibition of TGF-ßR demonstrated a potential to increase the efficacy of doxorubicin chemotherapy by the means of affecting cellular motility and restoring the anti-tumor immune responses.

Zoledronic acid-loaded lipidic nanoparticles enhance apoptosis and attenuate invasiveness by inhibiting epithelial to mesenchymal transition (EMT) in HepG2 cancer cells.

The aim of this study was to evaluate the potential of zoledronic acid (ZOL)-loaded lipidic nanoparticles (ZOL-NLCs) in enhancing the efficiency of paclitaxel (Pac) in the context of cytotoxicity, apoptosis, and invasiveness of HepG2 hepatocellular carcinoma cells. ZOL-NLCs were characterized in terms of zeta potential, particle size, and scanning electron microscope (SEM) as well as cell internalization. To measure the anti-proliferative effects of ZOL-NLCs, annexin-V/PI and MTT assays were employed. Real-time PCR and western blot analysis were performed to identify the molecular mechanisms underlying the apoptosis in response to the studied conditions. Furthermore, the transwell migration assay was applied to clarify the role of applied formulations on the invasiveness of HepG2 cells. Our results demonstrated that the optimized ZOL had an average particle size of 105 ± 6 nm with a nearly narrow size distribution. The IC50 values for ZOL and ZOL-NLCs were 90 ± 3.1 and 54.6 ± 2.4 µM, respectively. The population of apoptotic cells was increased from 17 ± 2% to 27 ± 4% (p < 0.05) in response to treatment with ZOL-NLCs. ZOL-loaded nanoparticles triggered the mRNA expression of Bax as pro-apoptotic marker and E-cadherin as epithelial one along with a decrease in mesenchymal marker, N-cadherin, and Bcl-xl as an anti-apoptotic marker in HepG2 cells. These outcomes were consistent with western blot analysis of protein expressions. Besides, ZOL-incorporated lipidic nanoparticles reduced the migration of HepG2 cells significantly. Our data suggest that the formulation of ZOL into lipidic nanoparticles can be considered a potential therapeutic approach that can enhance the efficacy of Pac chemotherapy.

Up-down regulation of HIF-1α in cancer progression.

Hypoxia induicible factor-1 alpha (HIF-1α) is a key transcription factor in cancer progression and target therapy in cancer. HIF-1α acts differently depending on presence or absence of Oxygen. In an oxygen-immersed environment, HIF-1α completely deactivated and destroyed by the ubiquitin proteasome pathway (UPP). In contrast, in the oxygen-free environment, it escapes destruction and enters to the nucleus of cells then upregulates many genes involved in cancer progression. Overexpressed HIF-1α and downstream genes support cancer progression through various mechanisms including angiogenesis, proliferation and survival of cells, metabolism reprogramming, invasion and metastasis, cancer stem cell maintenance, induction of genetic instability, and treatment resistance. HIF-1α can be provoked by signaling pathways unrelated to hypoxia during cancer progression. Therefore, cancer development and progression can be modulated by targeting HIF-1α and its downstream signaling molecules. In this regard, HIF-1α inhibitors which are categorized into the agents that regulate HIF-1α in gene, mRNA and protein levels used as an efficient way in cancer treatment. Also, HIF-1α expression can be negatively affected by the agents suppressing the activation of mTOR, PI3k/Akt and MAPK pathways.

Sensitization of A-549 lung cancer cells to Cisplatin by Quinacrine-loaded lipidic nanoparticles via suppressing Nrf2 mediated defense mechanism.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is believed to be responsible for the control mechanisms of cellular defense response and master regulator of antioxidant system by adjustment of endogenous antioxidants, phase II detoxifying enzymes and transporters, so inhibition of Nrf2 could be considered molecule target to overcome drug resistance and cancer progression. By harnessing liposome as an advanced nanoparticles transporter, we formulated Quinacrine known as nrf2 inhibitor into nano-carrier, and sensitized A-549 lung tumor cells to Cisplatin. The aim of this work was to prepare liposome nano-carriers to enhance the bioavailability of Quinacrine and to improve passive targeting in A549 cells. Quinacrine formulation into liposome exposed a mean particle size of 80±5 nm in passive targeting and 110±3 after decoration with chitosan oligosaccharides (COS), respectively. The highest amount of cell death (p<0.05) occurred with the co-incubation of the A549 cells with new formulation and Cisplatin. Additionally, Quinacrine-loaded liposomes declined Nrf2 expression more than Quinacrine alone (p<0.05). Correspondingly, the expression of Nrf2 downstream genes, MRP1, Trx, and bcl2 decreased significantly. Taking all the data into consideration, liposomes containing Quinacrine could ameliorate the effectiveness of Cisplatin by raising the permeability of cancer cells to the abovementioned chemical treatment and might be then given as a candidate to boost the therapeutic protocols in cancer patients.

Formulation of Stattic as STAT3 inhibitor in nanostructured lipid carriers (NLCs) enhances efficacy of doxorubicin in melanoma cancer cells.

Nowadays, nanoparticle-based combination therapy has been emerging as huge innovation in cancer treatment. Here, we studied the effect of Stattic (STAT3 inhibitor) loaded in nanostructured lipid carriers (NLCs) on enhancing the efficacy, cytotoxicity, and induction of apoptosis of doxorubicin in B16F10 mouse melanoma cancer cell. The evaluation of Stattic-loaded NLCs has been done in terms of zeta potential, particle size, scanning electron microscope (SEM), and cellular uptake. MTT assay was applied to evaluate the cell proliferation. Apoptotic cell death and identification of early and late apoptosis were assessed by DAPI staining and Annexin V/PI staining, respectively. Real-time RT-PCR was applied to measure the effects of doxorubicin and/or Stattic on key apoptotic genes such as Bad, Survivin, HIF1, and STAT3. The Stattic formulated into NLCs shown mean particle size of 56 ± 7 nm which was confirmed by SEM. The IC50 values for Stattic and doxorubicin were 2.95 ± 0.52 µM and 1.21 ± 0.36 µM, respectively. Stattic-loaded NLCs diminished percent of cell proliferation from 68 ± 6.8 to 54 ± 3.7% (p < 0.05). Combinational treatment of the cells with Stattic-loaded nanoparticles and doxorubicin give rise to a significant increase in the percentage of apoptosis (p < 0.05). The study of gene expression profile has shown a remarkable decrease in anti-apoptotic gene, Survivin, along with smooth decline in HIF1 as angiogenesis intermediator and increase in Bad mRNA levels. Our results recommend that NLCs as novel technology have potent strategy to augment efficacy of current chemotherapeutic agent in melanoma cancer cells.

Application of ɑ-Tocotrienol-Loaded Biocompatible Precirol in Attenuation of Doxorubicin Dose-Dependent Behavior in HUH-7 Hepatocarcinoma Cell Line.

Tumor-targeted nanoparticle delivery system has been known as a substitute and capable achievement in cancer treatment compared to conventional methods. In this study, we examined potential application of ɑ-tocotrienol-Precirol formulation to enhance efficiency of doxorubicin (DOX) in induction of apoptosis in HUH-7 hepatocarcinoma cells. ɑ-tocotrienol-loaded nanoparticles were characterized at the point of zeta potential, particle size, scanning electron microscope (SEM), and cell internalization. To evaluate antiproliferative effects of formulation, apoptosis, cell cycle procedure, flow cytometry, and MTT assays were employed. Optimum size of the ɑ-tocotrienol formulation revealed narrow size distribution with mean average of 78 ± 3 nm. IC50 values for ɑ-tocotrienol and ɑ-tocotrienol-nano structured lipid carriers after 24 h were 15 ± 0.6 and 10 ± 0.03 µM, respectively. After incubation of cells with ɑ-tocotrienol-loaded careers, the rate of cell proliferation decreased from 53 ± 6.1 to 34 ± 7.1% (P < 0.05). A significant improvement in the apoptosis percentage was revealed after treatment of the HUH-7 cell line with DOX and ɑ-tocotrienol careers (P < 0.05). Gene expression results demonstrated a marked decrease in survivin and increase in Bid and Bax levels. Our findings suggest that ɑ-tocotrienol-loaded nanoparticles elevate DOX efficacy in HUH-7 hepatocarcinoma cell.

Sensitization of MDA-MBA231 breast cancer cell to docetaxel by myricetin loaded into biocompatible lipid nanoparticles via sub-G1 cell cycle arrest mechanism.

The harmful dose-dependent side effects of chemotherapy drugs have caused the discovery of novel perspective to evaluate chemotherapy protocols. In this study, the potential application of Compritol was investigated as a major scaffold into nanostructured lipid careers to highlight myricetin efficiency in treatment of breast cancer cells along with codelivery of docetaxel (DXT). Characterization of myricetin-loaded NLCs was carried out by measuring the particle size and zeta potential, using the scanning electron microscopy. MTT, DAPI staining, flow cytometric, and RT-PCR (real-time) assays were used to recognize novel formulation behavior on cell cytotoxicity as well as recognizing molecular mechanism of formulation concerning apoptosis phenomenon. Myricetin-loaded NLCs reduced the cell viability from 50 ± 2.3 to 40 ± 1.3% (p < 0.05). Percentage of apoptosis improved with combination treatment of myricetin-loaded NLCs and DXT in the MDA-MBA231 breast cancer cells. Expression of antiapoptotic genes (survivin, Cyclin B1, and Mcl1) indicated a significant reduction in factor along with increment in proapoptotic factor Bax and Bid mRNA rates. Overall, our results represented that the NLC delivery system could be a promising strategy to enhance the effect of anticancer agents such as DXT on breast cancer.

Identification of Nrf2/STAT3 axis in induction of apoptosis through sub-G 1 cell cycle arrest mechanism in HT-29 colon cancer cells.

We investigated the role of stattic as an adjuvant molecule to increase the cytotoxicity of 5-fluorouracil (5-FU) through specific inhibition of molecular targets, signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid 2-related factor 2 (Nrf2) in HT-29 colon cancer cells. Cytotoxicity and apoptotic effects were investigated by methylthiazolyldiphenyl-​tetrazolium bromide assay and flow cytometry analysis, respectively. Real-time polymerase chain reaction was applied to assess the messenger RNA (mRNA) level of STAT3, Nrf2, and apoptotic genes including Bax, Bcl-xl, and Bcl-2. The antitumor effect of 5-FU in combination with stattic induced synergistic effect in HT-29 cells with combination indexes (CIs) 0.49. Flow cytometric results related to apoptotic confirmed that there was up to 40% increase in the population of apoptotic cells in HT-29 colon cancer cells incubated with 5-FU and stattic compared with control groups. Our data from gene expression determined a substantial diminish in the mRNA levels of the Nrf2 and antiapoptotic gene Bcl-2 along with a noticeable increase in the level of the proapoptotic Bax in HT-29 colon cells that underwent cotreatment with 5-FU and stattic (P < 0.05). Moreover, the results exhibited that stattic can be used as adjuvant chemotherapy besides the 5-FU. This therapeutic approach in colon cancer could mediate 5-FU chemoresistance via modulating therapeutic targets (ie, STAT3 and Nrf2 pathways) and decreased 5-FU-related adverse effects.

Adjuvant therapy with stattic enriches the anti-proliferative effect of doxorubicin in human ZR-75-1 breast cancer cells via arresting cell cycle and inducing apoptosis.

Adjuvant therapy with novel and effective component has been presented as a contrivance in breast cancer treatment versus the conventional methods. The current research was done to evaluate the implement of stattic, specific STAT3 inhibitor on the anti-proliferative and apoptotic behavior of doxorubicin on ZR-75-1 breast cancer cells. Cell viability was investigated by MTT assay, the percentage of apoptosis by DAPI staining, and Annexin V. Real Time-PCR was applied to find out the correlation between mechanistic roles of the STAT3 pathway and apoptotic signal in the modulation of Bcl-2 and Bax gene expressions axis. The IC50 values for doxorubicin and stattic were 2.5 ± 0.18 µM and 3.5 ± 0.28 µM, respectively. Combination index (CI) value for ZR-75-1 breast cancer was 0.72, which indicated a strong synergistic effect. Incubation of the cells with a combination of stattic and doxorubicin revealed a significant increase in growth inhibitory effect of doxorubicin with more than 50% decrease in proliferation rate and a two-fold increase in the percentage of apoptotic cells. Assessment of gene expression levels demonstrated a visible decrease in antiapoptotic Bcl-2 and Bcl-xl accompanied by an increase in pro-apoptotic Bax mRNA levels (p < 0.05). Taken together, our results show that combination of a STAT3 inhibitor and doxorubicin can be figured out as a promising approach for dealing of patients with breast cancers.

Fabrication of all-trans-retinoic acid-loaded biocompatible precirol: A strategy for escaping dose-dependent side effects of doxorubicin.

BACKGROUND: Drug delivery-based nanoparticles have been emerged to be an alternative and efficient approach to cancer therapy compared to conventional systems. Here, we investigated the role of all-trans retinoic acid (ATRA) formulated with precirol in increasing doxorubicin (Dox) induced apoptosis and cell cycle arrest in MDA-MB-231 breast cancer cells. METHODS: ATRA-loaded Nano structured lipid carriers (NLCs) were evaluated in terms of particle size, zeta potential, Fourier transforms infrared spectroscopy (FTIR), cell internalization, and scanning electron microscope (SEM). To understand molecular mechanism of apoptosis and cell cycle progression flow cytometric assay, MTT and DAPI staining was applied. Real time (RT)-PCR analysis was employed to investigate the expression of apoptosis related genes, including Survivin, Bcl-2 and Bax. RESULTS: The optimized ATRA formulation exhibited average particle size of 95±5nm with nearly narrow size distribution. The IC50 values for ATRA and doxorubicin were 48±0.4µM and 0.81±0.02µM, respectively. ATRA-loaded NLCs decreased percentage of cell proliferation from 51±7.2% to 36±4.1% (p <0.05). Co-treatment of the MDA-MB-231 cells with ATRA formulation and doxorubicin caused two-fold increase in the percentage of apoptosis (p<0.05). The results from gene expression exhibited a significant decrease in survivin along with increase at Bax mRNA levels accompanied by a slight increase in Bax/Bcl-2 ratio. CONCLUSION: Our results propose that ATRA encapsulated in precirol as a biocompatible compound augments the efficacy of Dox in cancer therapy.

Vitamin D-Loaded Nanostructured Lipid Carrier (NLC): A New Strategy for Enhancing Efficacy of Doxorubicin in Breast Cancer Treatment.

The dangerous dose-dependent side effects of anticancer agents triggered the finding of new approaches for elevated chemotherapy efficacy. This study investigated the potential application of nanostructured lipid careers (NLCs) in increasing vitamin D3 (VitD) effectiveness in breast cancer cell (MCF-7) in concurrent administration with doxorubicin (Dox). VitD-loaded NLCs were characterized by particle size, zeta potential, Fourier transform infrared spectroscopy, and scanning electron microscope. Cytotoxicity and molecular effects of formulation were evaluated by MTT, DAPI staining, flow cytometry, and real-time quantitative PCR assays. The formulation revealed mean particle size of 87±5 nm with a polydispersity index of 0.24 confirmed by SEM images. The IC50 values for VitD and Dox were 1.3 ± 0.04 and 0.65 ± 0.05 µM, respectively. VitD-loaded NLCs decreased the percentage of cell proliferation from 49 ± 7.2% to 37 ± 5.1% (P < 0.05). Cotreatment of the cells with VitD-loaded NLCs and Dox caused over a twofold increase in the percentage of apoptosis (P < 0.05). Gene expression profile demonstrated a significant decrease in antiapoptotic factor survivin along with increase in proapoptotic factor Bax mRNA levels. Overall, our results introduced the NLC technology as a novel strategy to elevate the efficacy of chemotherapeutics in breast cancer.

Combined Treatment with Stattic and Docetaxel Alters the Bax/Bcl-2 Gene Expression Ratio in Human Prostate Cancer Cells

Docetaxel, recognized as a stabilizing microtubule agent, is frequently administrated as a first line treatment for prostate cancers. Due to high side effects of monotherapy, however, combinations with novel adjuvants have emerged as an alternative strategy in cancer therapy protocols. Here, we investigated the combined effects of stattic and docetaxel on the DU145 prostate cancer cell line. Cytotoxicity was evaluated by MTT assay. To understand molecular mechanisms of stattic action, apoptotic related genes including Bcl-2, Mcl-1, Survivin and Bax were evaluated by real-time RT-PCR. Alteration in the expression of pro-apoptotic Bax and anti-apoptotic Bcl-2 genes and Bax/Bcl-2 ratio were investigated via the 2ΔΔCT method. The IC50 values for docetaxel and stattic were 3.7 ± 0.9 nM and 4.6±0.8 µM, respectively. Evaluation of key gene expression levels revealed a noticeable decrease in antiapoptotic Bcl-2 and Mcl-1 along with an increase in pro-apoptotic Bax mRNA levels (p<0.05). Our results suggest that combination of a STAT3 inhibitor with doctaxel can be considered as a potent strategy for induction of apoptosis via increasing Bax mRNA expression.

Dermal delivery of doxorubicin-loaded solid lipid nanoparticles for the treatment of skin cancer.

OBJECTIVE: Dermal delivery of Doxorubicin (Dox) would be an ideal way in maximising drug efficiency against skin cancer accompanying with minimising side effects. We investigated the potential of Dox-loaded Solid lipid nanoparticles (SLNs) for topical delivery against skin cancer. METHODS: In vitro and in vivo cytotoxicity of optimised formulation were evaluated on murine melanoma (B16F10) cells by MTT assay and melanoma induced Balb/C mice, respectively. Animal study followed by histological analysis. RESULTS: Optimised formulation showed mean particle size and encapsulation efficiency (EE) of 92 nm and 86% w/w (0.86% w/w value of encapsulated Dox in the lipid matrix), respectively. FTIR experiment confirmed drug-lipid interaction interpreting the observed high EE value for Dox. In vitro and in vivo results indicated the superiority of cytotoxic performance of Dox-loaded SLN compared to Dox solution. CONCLUSION: Our findings may open the possibilities for the topical delivery of Dox to the skin cancerous tissues.

Sustained release of melatonin: A novel approach in elevating efficacy of tamoxifen in breast cancer treatment.

BACKGROUND: Finding advanced anti-cancer agents with selective toxicity in tumor tissues is the goal of anticancer delivery systems. This study investigated potential application of nanostructured lipid carriers (NLCs) in increasing melatonin induced cytotoxicity and apoptosis in MCF-7 breast cancer cells. METHODS: Melatonin-loaded NLCs were characterized for particle size, zeta potential, Fourier transforms infrared spectroscopy, differential scanning calorimetry, cellular uptake, and scanning electron microscope (SEM). Anti-proliferative and apoptotic effects of new formulation were evaluated by MTT and flow cytometric assays, respectively. Gene expression of apoptotic markers including survivin, Bcl-2 and Bid were examined by Real time quantitative PCR. RESULTS: The optimized formulation of NLCs revealed mean particle size of 71±5nm with nearly narrow size distribution. The formulation exhibited an acceptable stability during four months in terms of size and lack of drug release. The IC50 values for melatonin and tamoxifen were 1.3±0.4mM and 30.7±5.2µM, respectively. Melatonin loaded NLCs decreased percentage of cell proliferation from 55±7.2% to 40±4.1% (p<0.05). Co-treatment of the cells with melatonin loaded nanoparticles and tamoxifen caused two fold increase in the percentage of apoptosis (p<0.05). Evaluation of gene expression profile demonstrated a marked decrease in anti-apoptotic survivin with increase in pro-apoptotic Bid mRNA levels. CONCLUSION: Taken together, our results suggest NLC technology as a promising delivery system, which elevates the efficacy of chemotherapeutics in breast cancer cells.

Six family of homeobox genes and related mechanisms in tumorigenesis protocols.

In recent years, the homeobox gene superfamily has been introduced as a master regulator in downstream target genes related to cell development and proliferation. An indispensable role of this family involved in organogenesis development has been widely demonstrated since expression of Six family led to a distinct increase in development of various organs. These functions of Six family genes are primarily based on structure as well as regulatory role in response to external or internal stimuli. In addition to these roles, mutation or aberrant expression of Six family plays a fundamental role in initiation of carcinogenesis, a multistep process including transformation, proliferation, angiogenesis, migration, and metastasis. This suggests that the Six superfamily members can be considered as novel target molecules to inhibit tumor growth and progression. This review focuses on the structure, function, and mechanisms of the Six family in cancer processes and possible strategies to apply these family members for diagnostic, prognostic, and therapeutic purposes.

The role of Six1 signaling in paclitaxel-dependent apoptosis in MCF-7 cell line.

The resistance of cancer cells to chemotherapeutic agents represents the main problem in cancer treatment. Despite intensive research, mechanisms of resistance have not yet been fully elucidated. Six1 signaling has an important role in the expansion of progenitor cell populations during early embryogenesis. Six1 gene overexpression has been strongly associated with aggressiveness, invasiveness, and poor prognosis of different cancers. In this study, we investigated the role of Six1 signaling in resistance of MCF-7 breast cancer cells to taxanes. We first established in vitro paclitaxel-resistant MCF-7 breast cancer cells. Morphological modifications in paclitaxel-resistant cells were examined via light microscopic images and fluorescence-activated cell sorting analysis. Applying quantitative real-time polymerase chain reaction, we measured Six1, B-cell lymphoma/leukemia(BCL-2), BAX, and P53 mRNA expression levels in both non-resistant and resistant cells. Resistant cells were developed from the parent MCF-7 cells by applying increasing concentrations of paclitaxel up to 64 nM. The inhibitory concentration 50% value in resistant cells increased from 3.5 ± 0.03 to 511 ± 10.22 nM (p = 0.015). In paclitaxel-resistant cells, there was a significant increase in Six1 and BCL-2 mRNA levels (p = 0.0007) with a marked decrease in pro-apoptotic Bax mRNA expression level (p = 0.03); however, there was no significant change in P53 expression (p = 0.025). Our results suggest that identifying cancer patients with high Six1 expression and then inhibition of Six1 signaling can improve the efficiency of chemotherapeutic agents in the induction of apoptosis.

Co-delivery with nano-quercetin enhances doxorubicin-mediated cytotoxicity against MCF-7 cells.

Quercetin, the plant-derived phenolic compounds, plays a pivotal role in controlling hemostasis, by having potent antioxidant and free-radical scavenging properties. This flavonoid in combination with chemotherapeutic drugs improves the efficacy of these agents in induction of apoptosis in cancer cells. This study investigated the role of nano-quercetin (phytosome) in doxorubicin-induced apoptosis. Nanoparticles were characterized for particle size, zeta potential, scanning electron microscopy (SEM) and differential scanning calorimetric assessments. Anti-proliferative effect of formulations was evaluated by MTT assay. mRNA expression levels of target genes were measured by real time RT-PCR. The mean size of nanoparticles was 85 ± 2 nm with nearly narrow size distribution which was confirmed by SEM analysis. Our results showed that co-treatment of MCF-7 breast cancer cells with nano-quercetin and doxorubicin increased the percentage of apoptosis from 40.11 ± 7.72-58 ± 7.13 (p < 0.05). Furthermore, mRNA expression levels for downstream genes including NQO1 and MRP1 showed a marked decrease (p < 0.05). Taken together, our results suggest that phytosome technology can elevate the efficacy of chemotherapeutics by increasing the permeability of tumor cells to chemical agents. Our findings introduce a novel phytosome-dependent strategy to improve delivery of doxorubicin to the breast cancerous tissues.

Folate-Targeted Nanostructured Lipid Carriers (NLCs) Enhance (Letrozol) Efficacy in MCF-7 Breast Cancer Cells

Objective: Targeted-drug-delivery based lipid nanoparticles has emerged as a new and effective approach in cancer chemotherapy. Here, we investigated the ability of folate-modified nanostructured lipid carriers (NLCs) to enhance letrozol (LTZ) efficacy in MCF-7 breast cancer cells. Methods: New formulations were evaluated regarding to particle size and scanning electron microscope (SEM) features. Anti-proliferative effects of LTZ loaded nanoparticles were examined by MTT assay. To understand molecular mechanisms of apoptosis and cell cycle progression, flow cytometric assays were applied. Results: Optimum size of nanoparticles was obtained in mean average of 98 ± 7 nm with a poly dispersity index (PDI) of 0.165. The IC50 value was achieved for LTZ was 2.2 ± 0.2 µM. Folate-NLC-LTZ increased the percentage of apoptotic cells from 24.6% to 42.2% compared LTZ alone (p<0.05). Furthermore, LTZ loaded folate targeted NLCs caused marked accumulation of cells in the subG1 phase. Conclusion: Taken together, our results concluded that folate targeted LTZ can be considered as potential delivery system which may overcome limitations of clinical application of LTZ and improve drug efficacy in tumor tissue.