LHRH-Conjugated Drugs as Targeted Therapeutic Agents for the Specific Targeting and Localized Treatment of Triple Negative Breast Cancer

A review on endoplasmic reticulum-dependent anti-breast cancer activity of herbal drugs: possible challenges and opportunities

Breast cancer (BC) is a major cause of cancer-related mortality across the globe and is especially highly prevalent in females. Based on the poor outcomes and several limitations of present management approaches in BC, there is an urgent need to focus and explore an alternate target and possible drug candidates against the target in the management of BC. The accumulation of misfolded proteins and subsequent activation of unfolded protein response (UPR) alters the homeostasis of endoplasmic reticulum (ER) lumen that ultimately causes oxidative stress in ER. The UPR activates stress-detecting proteins such as IRE1α, PERK, and ATF6, these proteins sometimes may lead to the activation of pro-apoptotic signaling pathways in cancerous cells. The ER stress-dependent antitumor activity could be achieved either through suppressing the adaptive UPR to make cells susceptible to ER stress or by causing chronic ER stress that may lead to triggering of pro-apoptotic signaling pathways. Several herbal drugs trigger ER-dependent apoptosis in BC cells. Therefore, this review discussed the role of fifty-two herbal drugs and their active constituents, focusing on disrupting the balance of the ER within cancer cells. Further, several challenges and opportunities have also been discussed in ER-dependent management in BC.Breast cancer (BC) is a major cause of cancer-related mortality across the globe and is especially highly prevalent in females. Based on the poor outcomes and several limitations of present management approaches in BC, there is an urgent need to focus and explore an alternate target and possible drug candidates against the target in the management of BC. The accumulation of misfolded proteins and subsequent activation of unfolded protein response (UPR) alters the homeostasis of endoplasmic reticulum (ER) lumen that ultimately causes oxidative stress in ER. The UPR activates stress-detecting proteins such as IRE1α, PERK, and ATF6, these proteins sometimes may lead to the activation of pro-apoptotic signaling pathways in cancerous cells. The ER stress-dependent antitumor activity could be achieved either through suppressing the adaptive UPR to make cells susceptible to ER stress or by causing chronic ER stress that may lead to triggering of pro-apoptotic signaling pathways. Several herbal drugs trigger ER-dependent apoptosis in BC cells. Therefore, this review discussed the role of fifty-two herbal drugs and their active constituents, focusing on disrupting the balance of the ER within cancer cells. Further, several challenges and opportunities have also been discussed in ER-dependent management in BC.

Lipid-Based Nanocarrier by Targeting with LHRH Peptide: A Promising Approach for Prostate Cancer Radio-Imaging and Therapy

Prostate cancer is a prevalently detected malignancy with a dismal prognosis. Luteinizing-hormone-releasing-hormone (LHRH) receptors are overexpressed in such cancer cells, to which the LHRH-decapeptide can specifically bind. A lipid-polyethylene glycol-conjugated new LHRH-decapeptide analogue (D-P-HLH) was synthesized and characterized. D-P-HLH-coated and anticancer drug doxorubicin (DX)-loaded solid lipid nanoparticles (F-DX-SLN) were formulated by the cold homogenization technique and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, differential scanning calorimetry, dynamic light scattering, electron microscopy, entrapment efficiency, and drug-release profile studies. F-DX-SLN allows site-specific DX delivery by reducing the side effects of chemotherapy. Cancer cells could precisely take up F-DX-SLN by targeting specific receptors, boosting the cytotoxicity at the tumor site. The efficacy of F-DX-SLN on PC3/SKBR3 cells by the MTT assay revealed that F-DX-SLN was more cytotoxic than DX and/or DX-SLN. Flow cytometry and confocal microscopic studies further support F-DX-SLNs' increased intracellular absorption capability in targeting LHRH overexpressed cancer cells. F-DX-SLN ensured high apoptotic potential, noticeably larger mitochondrial transmembrane depolarization action, as well as the activation of caspases, a longer half-life, and greater plasma concentration. F-DX-SLN/DX-SLN was radiolabeled with technetium-99m; scintigraphic imaging studies established its tumor selectivity in PC3 tumor-bearing nude mice. The efficacy of the formulations in cancer treatment, in vivo therapeutic efficacy tests, and histopathological studies were also conducted. Results clearly indicate that F-DX-SLN exhibits sustained and superior targeted administration of anticancer drugs, thus opening up the possibility of a drug delivery system with precise control and targeting effects. F-DX-SLN could also provide a nanotheranostic approach with improved efficacy for prostate cancer therapy.

Luteinizing Hormone-Releasing Hormone (LHRH)-Conjugated Cancer Drug Delivery from Magnetite Nanoparticle-Modified Microporous Poly-Di-Methyl-Siloxane (PDMS) Systems for the Targeted Treatment of Triple Negative Breast Cancer Cells

This study presents LHRH conjugated drug delivery via a magnetite nanoparticle-modified microporous Poly-Di-Methyl-Siloxane (PDMS) system for the targeted suppression of triple-negative breast cancer cells. First, the MNP-modified PDMS devices are fabricated before loading with targeted and untargeted cancer drugs. The release kinetics from the devices are then studied before fitting the results to the Korsmeyer-Peppas model. Cell viability and cytotoxicity assessments are then presented using results from the Alamar blue assay. Apoptosis induction is then elucidated using flow cytometry. The in vitro drug release studies demonstrated a sustained and controlled release of unconjugated drugs (Prodigiosin and paclitaxel) and conjugated drugs [LHRH conjugated paclitaxel (PTX+LHRH) and LHRH-conjugated prodigiosin (PG+LHRH)] from the magnetite nanoparticle modified microporous PDMS devices for 30 days at 37 °C, 41 °C, and 44 °C. At 24, 48, 72, and 96 h, the groups loaded with conjugated drugs (PG+LHRH and PTX+LHRH) had a significantly higher (p < 0.05) percentage cell growth inhibition than the groups loaded with unconjugated drugs (PG and PTX). Additionally, throughout the study, the MNP+PDMS (without drug) group exhibited a steady rise in the percentage of cell growth inhibition. The flow cytometry results revealed a high incidence of early and late-stage apoptosis. The implications of the results are discussed for the development of biomedical devices for the localized and targeted release of cancer drugs that can prevent cancer recurrence following tumor resection.

Use of Drug Sensitisers to Improve Therapeutic Index in Cancer

The clinical management of malignant tumours is challenging, often leading to severe adverse effects and death. Drug resistance (DR) antagonises the effectiveness of treatments, and increasing drug dosage can worsen the therapeutic index (TI). Current efforts to overcome DR predominantly involve the use of drug combinations, including applying multiple anti-cancerous drugs, employing drug sensitisers, which are chemical agents that enhance pharmacokinetics (PK), including the targeting of cellular pathways and regulating pertinent membrane transporters. While combining multiple compounds may lead to drug-drug interactions (DDI) or polypharmacy effect, the use of drug sensitisers permits rapid attainment of effective treatment dosages at the disease site to prevent early DR and minimise side effects and will reduce the chance of DDI as lower drug doses are required. This review highlights the essential use of TI in evaluating drug dosage for cancer treatment and discusses the lack of a unified standard for TI within the field. Commonly used benefit-risk assessment criteria are summarised, and the critical exploration of the current use of TI in the pharmaceutical industrial sector is included. Specifically, this review leads to the discussion of drug sensitisers to facilitate improved ratios of effective dose to toxic dose directly in humans. The combination of drug and sensitiser molecules might see additional benefits to rekindle those drugs that failed late-stage clinical trials by the removal of detrimental off-target activities through the use of lower drug doses. Drug combinations and employing drug sensitisers are potential means to combat DR. The evolution of drug combinations and polypharmacy on TI are reviewed. Notably, the novel binary weapon approach is introduced as a new opportunity to improve TI. This review emphasises the urgent need for a criterion to systematically evaluate drug safety and efficiency for practical implementation in the field.

In-vivo studies of targeted and localized cancer drug release from microporous poly-di-methyl-siloxane (PDMS) devices for the treatment of triple negative breast cancer

Triple-negative breast cancer (TNBC) treatment is challenging and frequently characterized by an aggressive phenotype and low prognosis in comparison to other subtypes. This paper presents fabricated implantable drug-loaded microporous poly-di-methyl-siloxane (PDMS) devices for the delivery of targeted therapeutic agents [Luteinizing Hormone-Releasing Hormone conjugated paclitaxel (PTX-LHRH) and Luteinizing Hormone-Releasing Hormone conjugated prodigiosin (PG-LHRH)] for the treatment and possible prevention of triple-negative cancer recurrence. In vitro assessment using the Alamar blue assay demonstrated a significant reduction (p < 0.05) in percentage of cell growth in a time-dependent manner in the groups treated with PG, PG-LHRH, PTX, and PTX-LHRH. Subcutaneous triple-negative xenograft breast tumors were then induced in athymic female nude mice that were four weeks old. Two weeks later, the tumors were surgically but partially removed, and the device implanted. Mice were observed for tumor regrowth and organ toxicity. The animal study revealed that there was no tumor regrowth, six weeks post-treatment, when the LHRH targeted drugs (LHRH-PTX and LHRH-PGS) were used for the treatment. The possible cytotoxic effects of the released drugs on the liver, kidney, and lung are assessed using quantitative biochemical assay from blood samples of the treatment groups. Ex vivo histopathological results from organ tissues showed that the targeted cancer drugs released from the implantable drug-loaded device did not induce any adverse effect on the liver, kidneys, or lungs, based on the results of qualitative toxicity studies. The implications of the results are discussed for the targeted and localized treatment of triple negative breast cancer.

Therapeutic dosing and targeting efficacy of Pt-Mal-LHRH towards triple negative breast cancer

OBJECTIVE

Pt-Mal-LHRH is a newly synthesized chemotherapeutic agent that was designed to selectively target the luteinizing hormone-releasing hormone (LHRH) receptor expressed by triple negative breast cancer (TNBC). The aim of this study was to evaluate the therapeutic dosing, tumor reduction efficacy, and selective distribution of Pt-Mal-LHRH in-vivo.

METHODS AND RESULTS

LHRH tissue expression levels in-vivo were investigated using western blotting and LHRH was found to be increased in reproductive tissues (mammary, ovary, uterus). Further, Pt-Mal-LHRH was found to have increased TNBC tumor tissue platinum accumulation compared to carboplatin by inductively coupled plasma mass spectrometry analysis. The platinum family, compound carboplatin, was selected for comparison due to its similar chemical structure and molar equivalent doses were evaluated. Moreover, in-vivo distribution data indicated selective targeting of Pt-Mal-LHRH by enhanced reproductive tissue accumulation compared to carboplatin. Further, TNBC tumor growth was found to be significantly attenuated by Pt-Mal-LHRH compared to carboplatin in both the 4T1 and MDA-MB-231 tumor models. There was a significant reduction in tumor volume in the 4T1 tumor across Pt-Mal-LHRH doses (2.5-20 mg/kg/wk) and in the MDA-MB-231 tumor at the dose of 10 mg/kg/wk in models conducted by an independent contract testing laboratory.

CONCLUSION

Our data indicates Pt-Mal-LHRH is a targeting chemotherapeutic agent towards the LHRH receptor and reduces TNBC tumor growth in-vivo. This study supports drug conjugation design models using the LHRH hormone for chemotherapeutic delivery as Pt-Mal-LHRH was found to be a more selective and efficacious than carboplatin. Further examination of Pt-Mal-LHRH is warranted for its clinical use in TNBCs, along with, other reproductive cancers overexpressing the LHRH receptor.

Targeted drug-loaded PLGA-PCL microspheres for specific and localized treatment of triple negative breast cancer

The paper presents the results of the experimental and analytical study of targeted drug-loaded polymer-based microspheres made from blend polymer of polylactic-co-glycolic acid and polycaprolactone (PLGA-PCL) for targeted and localized cancer drug delivery. In vitro sustained release with detailed thermodynamically driven drug release kinetics, over a period of three months using encapsulated targeted drugs (prodigiosin-EphA2 or paclitaxel-EphA2) and control drugs [Prodigiosin (PGS), and paclitaxel (PTX)] were studied. Results from in vitro study showed a sustained and localized drug release that is well-characterized by non-Fickian Korsmeyer-Peppas kinetics model over the range of temperatures of 37 °C (body temperature), 41 °C, and 44 °C (hyperthermic temperatures). The in vitro alamar blue, and flow cytometry assays in the presence of the different drug-loaded polymer formulations resulted to cell death and cytotoxicity that was evidence through cell inhibition and late apoptosis on triple negative breast cancer (TNBC) cells (MDA-MB 231). In vivo studies carried out on groups of 4-week-old athymic nude mice that were induced with subcutaneous TNBC, showed that the localized release of the EphA2-conjugated drugs was effective in complete elimination of residual tumor after local surgical resection. Finally, ex vivo histopathological analysis carried out on the euthanized mice revealed no cytotoxicity and absence of breast cancer metastases in the liver, kidney, and lungs 12 weeks after treatment. The implications of the results are then discussed for the development of encapsulated EphA2-conjugated drugs formulation in the specific targeting, localized, and sustain drug release for the elimination of local recurred TNBC tumors after surgical resection.

Engineering BinB Pore-Forming Toxin for Selective Killing of Breast Cancer Cells

Breast cancer is one of the most common cancers in women worldwide. Conventional cancer chemotherapy always has adverse side effects on the patient's healthy tissues. Consequently, combining pore-forming toxins with cell-targeting peptides (CTPs) is a promising anticancer strategy for selectively destroying cancer cells. Here, we aim to improve the target specificity of the BinB toxin produced from Lysinibacillus sphaericus (Ls) by fusing a luteinizing hormone-releasing hormone (LHRH) peptide to its pore-forming domain (BinB_C) to target MCF-7 breast cancer cells as opposed to human fibroblast cells (Hs68). The results showed that LHRH-BinB_C inhibited MCF-7 cell proliferation in a dose-dependent manner while leaving Hs68 cells unaffected. BinB_C, at any concentration tested, did not affect the proliferation of MCF-7 or Hs68 cells. In addition, the LHRH-BinB_C toxin caused the efflux of the cytoplasmic enzyme lactate dehydrogenase (LDH), demonstrating the efficacy of the LHRH peptide in directing the BinB_C toxin to damage the plasma membranes of MCF-7 cancer cells. LHRH-BinB_C also caused MCF-7 cell apoptosis by activating caspase-8. In addition, LHRH-BinB_C was predominantly observed on the cell surface of MCF-7 and Hs68 cells, without colocalization with mitochondria. Overall, our findings suggest that LHRH-BinB_C could be investigated further as a potential cancer therapeutic agent.

LHRH conjugated gold nanoparticles assisted efficient ovarian cancer targeting evaluated via spectral photon-counting CT imaging: a proof-of-concept research

Emerging multifunctional nanoparticulate formulations take advantage of nano-meter scale size and surface chemistry to work as a therapeutic delivery agent and a diagnostic tool for non-invasive real-time monitoring using imaging technologies. Here, we evaluate the selective uptake of 18 nm and 80 nm sized gold nanoparticles (AuNPs) by SKOV3 (4 times higher) ovarian cancer (OC) cells (compared to OVCAR5) in vitro, quantified by inductively coupled plasma (ICP) and MARS spectral photon-counting CT imaging (MARS SPCCT). Based on in vitro analysis, pristine AuNPs (18 nm) and surface modified AuNPs (18 nm) were chosen as a contrast agent for MARS SPCCT. The chemical analysis by FTIR spectroscopy confirmed the luteinizing hormone-releasing hormone (LHRH) conjugation to the AuNPs surface. For the first time, LHRH conjugated AuNPs were used for in vitro and selective in vivo OC targeting. The ICP-MS analysis confirmed preferential uptake of LHRH modified AuNPs by organs residing in the abdominal cavity with OC nodules (pancreas: 0.46 ng mg^-1, mesentery: 0.89 ng mg^-1, ovary: 1.43 ng mg^-1, and abdominal wall: 2.12 ng mg^-1) whereas the MARS SPCCT analysis suggested scattered accumulation of metal around the abdominal cavity. Therefore, the study showed the exciting potential of LHRH conjugated AuNPs to target ovarian cancer and also as a potential contrast agent for novel SPCCT imaging technology.

Learn from antibody–drug conjugates: consideration in the future construction of peptide-drug conjugates for cancer therapy

Cancer is one of the leading causes of death worldwide due to high heterogeneity. Although chemotherapy remains the mainstay of cancer therapy, non-selective toxicity and drug resistance of mono-chemotherapy incur broad criticisms. Subsequently, various combination strategies have been developed to improve clinical efficacy, also known as cocktail therapy. However, conventional “cocktail administration” is just passable, due to the potential toxicities to normal tissues and unsatisfactory synergistic effects, especially for the combined drugs with different pharmacokinetic properties. The drug conjugates through coupling the conventional chemotherapeutics to a carrier (such as antibody and peptide) provide an alternative strategy to improve therapeutic efficacy and simultaneously reduce the unspecific toxicities, by virtue of the advantages of highly specific targeting ability and potent killing effect. Although 14 antibody–drug conjugates (ADCs) have been approved worldwide and more are being investigated in clinical trials so far, several limitations have been disclosed during clinical application. Compared with ADCs, peptide-drug conjugates (PDCs) possess several advantages, including easy industrial synthesis, low cost, high tissue penetration and fast clearance. So far, only a handful of PDCs have been approved, highlighting tremendous development potential. Herein, we discuss the progress and pitfalls in the development of ADCs and underline what can learn from ADCs for the better construction of PDCs in the future.

Prodigiosin from Serratia Marcescens in Cockroach Inhibits the Proliferation of Hepatocellular Carcinoma Cells through Endoplasmic Reticulum Stress-Induced Apoptosis

Hepatocellular carcinoma (HCC) is the most common primary liver malignant tumor, and the targeted therapy for HCC is very limited. Our previous study demonstrated that prodigiosin(PG), a secondary metabolite from Serratia marcescens found in the intestinal flora of cockroaches, inhibits the proliferation of HCC and increases the expression of CHOP, a marker protein for endoplasmic reticulum stress (ERS)-mediated apoptosis, in a dose-dependent manner. However, the mechanisms underlying the activity of PG in vivo and in vitro are unclear. This study explored the molecular mechanisms of PG-induced ERS against liver cancer in vitro and in vivo. The apoptosis of hepatocellular carcinoma cells induced by PG through endoplasmic reticulum stress was observed by flow cytometry, colony formation assay, cell viability assay, immunoblot analysis, and TUNEL assay. The localization of PG in cells was observed using laser confocal fluorescence microscopy. Flow cytometry was used to detect the intracellular Ca2+ concentration after PG treatment. We found that PG could promote apoptosis and inhibit the proliferation of HCC. It was localized in the endoplasmic reticulum of HepG2 cells, where it induces the release of Ca2+. PG also upregulated the expression of key unfolded response proteins, including PERK, IRE1α, Bip, and CHOP, and related apoptotic proteins, including caspase3, caspase9, and Bax, but down-regulated the expression of anti-apoptotic protein Bcl-2 in liver cancer. Alleviating ERS reversed the above phenomenon. PG had no obvious negative effects on the functioning of the liver, kidney, and other main organs in nude mice, but the growth of liver cancer cells was inhibited by inducing ERS in vivo. The findings of this study showed that PG promotes apoptosis of HCC by inducing ERS.

Enhancing the therapeutic efficacy of nanoparticles for cancer treatment using versatile targeted strategies

Poor targeting of therapeutics leading to severe adverse effects on normal tissues is considered one of the obstacles in cancer therapy. To help overcome this, nanoscale drug delivery systems have provided an alternative avenue for improving the therapeutic potential of various agents and bioactive molecules through the enhanced permeability and retention (EPR) effect. Nanosystems with cancer-targeted ligands can achieve effective delivery to the tumor cells utilizing cell surface-specific receptors, the tumor vasculature and antigens with high accuracy and affinity. Additionally, stimuli-responsive nanoplatforms have also been considered as a promising and effective targeting strategy against tumors, as these nanoplatforms maintain their stealth feature under normal conditions, but upon homing in on cancerous lesions or their microenvironment, are responsive and release their cargoes. In this review, we comprehensively summarize the field of active targeting drug delivery systems and a number of stimuli-responsive release studies in the context of emerging nanoplatform development, and also discuss how this knowledge can contribute to further improvements in clinical practice.

Triptorelin-functionalized PEG-coated biosynthesized gold nanoparticles: Effects of receptor-ligand interactions on adhesion to triple negative breast cancer cells

This paper presents the results of an experimental and computational study of the adhesion of triptorelin-conjugated PEG-coated biosynthesized gold nanoparticles (GNP-PEG-TRP) to triple-negative breast cancer (TNBC) cells. The adhesion is studied at the nanoscale using a combination of atomic force microscopy (AFM) experiments and molecular dynamics (MD) simulations. The AFM measurements showed that the triptorelin-functionalized gold nanoparticles (GNP-TRP and GNP-PEG-TRP) have higher adhesion to triple-negative breast cancer cells (TNBC) than non-tumorigenic breast cells. The increased adhesion of GNP-TRP and GNP-PEG-TRP to TNBC is also attributed to the overexpression of LHRH receptors on the surfaces of both TNBC. Finally, the molecular dynamics model reveals insights into the effects of receptor density, molecular configuration, and receptor-ligand docking characteristics on the interactions of triptorelin-functionalized PEG-coated gold nanoparticles with TNBC. A three to nine-fold increase in the adhesion is predicted between triptorelin-functionalized PEG-coated gold nanoparticles and TNBC cells. The implications of the results are then discussed for the specific targeting of TNBC.

Stimuli-responsive, dual-function prodrug encapsulated in hyaluronic acid micelles to overcome doxorubicin resistance

Multidrug resistance (MDR) is the main challenge faced by cancer chemotherapy. Drug-conjugate offers a promising strategy for breast cancer therapy. In this regard, we developed a DNVM multifunctional drug delivery system by crosslinking doxorubicin (DOX) and vitamin E succinate (VES) with a pH-sensitive hydrazone bond and then encapsulated the DOX-NN-VES prodrug into pH-sensitive hyaluronic acid-2-(octadecyloxy)-1,3-dioxan-5-amine (HOD) micelles. DOX resistant MCF-7/ADR cell were adopted as a model to study the capability and mechanism of MDR reversal. DNVM exhibited much higher cytotoxicity and cell uptake efficiency compared with that of acid-insensitive DOX-VES loaded HOD micelles (DVSM) and DOX loaded HOD micelles (DOXM), indicating the better capacity of DNVM for the reversal of MDR. Moreover, DNVM prevented drug efflux more effectively, inhibited the expression of P-gp, induced excessive production of reactive oxygen species and affected the expression of apoptosis-related proteins. In vivo experiments showed that DNVM significantly inhibited the tumor growth with no obvious changes in the body weight of MCF-7/ADR cells-bearing nude mice. The results suggested that the "double gain" DNVM can synergistically enhance the efficacy of chemotherapeutics for DOX resistant tumor cells and has the potential to overcome tumor MDR. STATEMENT OF SIGNIFICANCE: A dual-functional pH-sensitive doxorubicin - vitamin E succinate prodrug was developed and loaded into tumor microenvironment-sensitive hyaluronic acid-2-(octadecyloxy)-1,3-dioxan-5-amine micelle system (DNVM) for sequencing stimuli-release and overcoming doxorubicin resistance. The "double gain" DNVM can synergistically enhance the efficacy of chemotherapeutics for doxorubicin resistant tumor cells and has the potential to overcome tumor multiple drug resistance.

Plant Derived Bioactive Compounds, Their Anti-Cancer Effects and In Silico Approaches as an Alternative Target Treatment Strategy for Breast Cancer: An Updated Overview

Cancer is one of the most common malignant diseases that occur worldwide, among which breast cancer is the second leading cause of death in women. The subtypes are associated with differences in the outcome and were selected for treatments according to the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor. Triple-negative breast cancer, one of the subtypes of breast cancer, is difficult to treat and can even lead to death. If breast cancer is not treated during the initial stages, it may spread to nearby organs, a process called metastasis, through the blood or lymph system. For in vitro studies, MCF-7, MDA-MB-231, MDA-MB-468, and T47B are the most commonly used breast cancer cell lines. Clinically, chemotherapy and radiotherapy are usually expensive and can also cause side effects. To overcome these issues, medicinal plants could be the best alternative for chemotherapeutic drugs with fewer side effects and cost-effectiveness. Furthermore, the genes involved in breast cancer can be regulated and synergized with signaling molecules to suppress the proliferation of breast cancer cells. In addition, nanoparticles encapsulating (nano-encapsulation) medicinal plant extracts showed a significant reduction in the apoptotic and cytotoxic activities of breast cancer cells. This present review mainly speculates an overview of the native medicinal plant derived anti-cancerous compounds with its efficiency, types and pathways involved in breast cancer along with its genes, the mechanism of breast cancer brain metastasis, chemoresistivity and its mechanism, bioinformatics approaches which could be an effective alternative for drug discovery.

Receptor-Mediated Targeted Delivery of Surface-ModifiedNanomedicine in Breast Cancer: Recent Update and Challenges

Breast cancer therapeutic intervention continues to be ambiguous owing to the lack of strategies for targeted transport and receptor-mediated uptake of drugs by cancer cells. In addition to this, sporadic tumor microenvironment, prominent restrictions with conventional chemotherapy, and multidrug-resistant mechanisms of breast cancer cells possess a big challenge to even otherwise optimal and efficacious breast cancer treatment strategies. Surface-modified nanomedicines can expedite the cellular uptake and delivery of drug-loaded nanoparticulate constructs through binding with specific receptors overexpressed aberrantly on the tumor cell. The present review elucidates the interesting yet challenging concept of targeted delivery approaches by exploiting different types of nanoparticulate systems with multiple targeting ligands to target overexpressed receptors of breast cancer cells. The therapeutic efficacy of these novel approaches in preclinical models is also comprehensively discussed in this review. It is concluded from critical analysis of related literature that insight into the translational gap between laboratories and clinical settings would provide the possible future directions to plug the loopholes in the process of development of these receptor-targeted nanomedicines for the treatment of breast cancer.

Microbial transglutaminase nanoflowers as an alternative nanomedicine for breast cancer theranostics

Breast cancer is the most common malignancy among women. With the aim of decreasing the toxicity of conventional breast cancer treatments, an alternative that could provide appropriate and effective drug utilization was envisioned. Thus, we contemplated and compared the in vitro effects of microbial transglutaminase nanoflowers (MTGase NFs) on breast cancer cells (MCF-7). Transglutaminase is an important regulatory enzyme acting as a site-specific cross-linker for proteins. With the versatility of MTGase facilitating the nanoflower formation by acting as molecular glue, it was demonstrated to have anti-cancer properties. The rational drug design based on a transglutaminase enzyme-assisted approach led to the uniform shape of petals in these nanoflowers, which had the capacity to act directly as an anti-cancer drug. Herein, we report the anti-cancer characteristics portrayed by enzymatic MTGase NFs, which are biocompatible in nature. This study demonstrated the prognostic and therapeutic significance of MTGase NFs as a nano-drug in breast cancer treatment. The results on MCF-7 cells showed a significantly improved in vitro therapeutic efficacy. MTGase NFs were able to exhibit inhibitory effects on cell viability (IC₅₀-8.23 μg ml⁻¹) within 24 h of dosage. To further substantiate its superior anti-proliferative role, the clonogenic potential was measured to be 62.8%, along with migratory inhibition of cells (3.76-fold change). Drastic perturbations were induced (4.61-fold increase in G0/G1 phase arrest), pointed towards apoptotic induction with a 58.9% effect. These results validated the role of MTGase NFs possessing a cytotoxic nature in mitigating breast cancer. Thus, MTGase bestows distinct functionality towards therapeutic nano-modality, i.e., nanoflowers, which shows promise in cancer treatment.

Development of a novel therapeutic nano-modality in the form of enzymatic transglutaminase nanoflowers; endowed with anti-cancerous action against breast cancers.

Recent advances in active targeting of nanomaterials for anticancer drug delivery

One of the challenges in cancer chemotherapy is the low target to non-target ratio of therapeutic agents which incur severe adverse effect on the healthy tissues. In this regard, nanomaterials have tremendous potential for impacting cancer therapy by altering the toxicity profile of the drug. Some of the striking advantages provided by the nanocarriers mediated targeted drug delivery are relatively high build-up of drug concentration at the tumor site, improved drug content in the formulation and enhanced colloidal stability. Further, nanocarriers with tumor-specific moieties can be targeted to the cancer cell through cell surface receptors, tumor antigens and tumor vasculatures with high affinity and accuracy. Moreover, it overcomes the bottleneck of aimless drug biodistribution, undesired toxicity and heavy dosage of administration. This review discusses the recent developments in active targeting of nanomaterials for anticancer drug delivery through cancer cell surface targeting, organelle specific targeting and tumor microenvironment targeting strategies. Special emphasis has been given towards cancer cell surface and organelle specific targeting as delivery of anticancer drugs through these routes have made paradigm change in cancer management. Further, the current challenges and future prospects of nanocarriers mediated active drug targeting are also demonstrated.

Fatty acid synthase as a feasible biomarker for triple negative breast cancer stem cell subpopulation cultured on electrospun scaffolds

There is no targeted therapy for triple negative breast cancer (TNBC), which presents an aggressive profile and poor prognosis. Recent studies noticed the feasibility of breast cancer stem cells (BCSCs), a small population responsible for tumor initiation and relapse, to become a novel target for TNBC treatments. However, new cell culture supports need to be standardized since traditional two-dimensional (2D) surfaces do not maintain the stemness state of cells. Hence, three-dimensional (3D) scaffolds represent an alternative to study in vitro cell behavior without inducing cell differentiation. In this work, electrospun polycaprolactone scaffolds were used to enrich BCSC subpopulation of MDA-MB-231 and MDA-MB-468 TNBC cells, confirmed by the upregulation of several stemness markers and the existence of an epithelial-to-mesenchymal transition within 3D culture. Moreover, 3D-cultured cells displayed a shift from MAPK to PI3K/AKT/mTOR signaling pathways, accompanied by an enhanced EGFR and HER2 activation, especially at early cell culture times. Lastly, the fatty acid synthase (FASN), a lipogenic enzyme overexpressed in several carcinomas, was found to be hyperactivated in stemness-enriched samples. Its pharmacological inhibition led to stemness diminishment, overcoming the BCSC expansion achieved in 3D culture. Therefore, FASN may represent a novel target for BCSC niche in TNBC samples.

PLGA-CS-PEG Microparticles for Controlled Drug Delivery in the Treatment of Triple Negative Breast Cancer Cells

In this study, we explore the development of controlled PLGA-CS-PEG microspheres, which are used to encapsulate model anticancer drugs (prodigiosin (PGS) or paclitaxel (PTX)) for controlled breast cancer treatment. The PLGA microspheres are blended with hydrophilic polymers (chitosan and polyethylene glycol) in the presence of polyvinyl alcohol (PVA) that were synthesized via a water-oil-water (W/O/W) solvent evaporation technique. Chitosan (CS) and polyethylene glycol (PEG) were used as surface-modifying additives to improve the biocompatibility and reduce the adsorption of plasma proteins onto the microsphere surfaces. These PLGA-CS-PEG microspheres are loaded with varying concentrations (5 and 8 mg/mL) of PGS or PTX, respectively. Scanning electron microscopy (SEM) revealed the morphological properties while Fourier transform infrared spectroscopy (FTIR) was used to elucidate the functional groups of drug-loaded PLGA-CS-PEG microparticles. A thirty-day, in vitro, encapsulated drug (PGS or PTX) release was carried out at 37 °C, which corresponds to human body temperature, and at 41 °C and 44 °C, which correspond to hyperthermic temperatures. The thermodynamics and kinetics of in vitro drug release were also elucidated using a combination of mathematical models and the experimental results. The exponents of the Korsmeyer–Peppas model showed that the kinetics of drug release was well characterized by anomalous non-Fickian drug release. Endothermic and nonspontaneous processes are also associated with the thermodynamics of drug release. Finally, the controlled in vitro release of cancer drugs (PGS and PTX) is shown to decrease the viability of MDA-MB-231 cells. The implications of the results are discussed for the development of drug-encapsulated PLGA-CS-PEG microparticles for the controlled release of cancer drugs in treatment of triple negative breast cancer.

Cell cycle arrest-mediated cell death by morin in MDA-MB-231 triple-negative breast cancer cells

BACKGROUND

Morin, a flavonoid extracted from Moraceace family and exhibits several pharmacological activities including anti-cancer activity. Although the anticancer activity of morin in breast cancer was estimated in some investigations, the pharmaceutical mechanism has not been fully elucidated. Therefore, we investigated to unveil the detail signaling pathway in morin-treated in MDA-MB-231 triple-negative breast cancer cells.

METHODS

The cytotoxicity of morin in MDA-MB-231 cells was confirmed by sulforhodamine B (SRB) assay and colony formation assay. Flow cytometry was performed to examine the cell cycle and cell death patterns and the protein expression and phosphorylation were detected by western blotting.

RESULTS

Our results showed that morin inhibited MDA-MB-231 cells proliferation in time and concentration-dependent manner. Morphological changes were observed when treated with various concentration of morin in MDA-MB-231 cells. In regard to protein expression, morin induced the phosphorylation of ERK and p-H2A.X and decreased the level of DNA repair markers, RAD51 and survivin. In addition, flow cytometry showed S and G2/M arrest by morin that was associated with the decrease in the protein expression of cyclin A2 and cyclin B1 and upregulation of p21. Interestingly, annexin V/PI staining result clearly showed that morin induced cell death without apoptosis. Furthermore, attenuated FoxM1 by morin was co-related with cell cycle regulators including p21, cyclin A2 and cyclin B1.

CONCLUSION

Taken together, our study indicates that morin-induced cell death of MDA-MB-231 is caused by sustained cell cycle arrest via the induction of p21 expression by activation of ERK and repression of FOXM1 signaling pathways.

In vitro studies of Annona muricata L. extract-loaded electrospun scaffolds for localized treatment of breast cancer

This paper presents in vitro studies of the sustained release of Annona muricata leaf extracts (AME) from hybrid electrospun fibers for breast cancer treatment. Electrospun hybrid scaffolds were fabricated from crude AME extracts, poly(lactic-co-glycolic acid)/gelatin (PLGA/Ge) and pluronic F127. The physicochemical properties of the AME extract and scaffolds were studied. The antiproliferative effects of the scaffolds were also assessed on breast cancer (MCF-7 and MDA-MB-231) and non-tumorigenic breast (MCF10A) cell lines. Scanning electron microscope micrographs revealed a random network of micro- and submicron fibers. In vitro drug release profiles, governed by quasi-Fickian diffusion at pH 7.4 and non-Fickian super case II at pH 6.7, showed initial burst AME release from the PLGA/Ge-AME and PLGA/Ge-F127/AME fibers at pH 7.4, and burst release from PLGA/Ge-F127/AME (not observed from PLGA/Ge-AME) at pH 6.7. Then, a slower, sustained release of the remaining AME from the fibers, attributed to the onset of degradation of the PLGA/Ge backbone, was observed for the next 72 hr. The cumulative release of AME was 89.33 ± 0.73% (PLGA/Ge-AME) and 51.17 ± 7.96% (PLGA/Ge-F127/AME) at pH 7.4, and 9.27 ± 2.3% and 73.5 ± 4.5%, respectively, at pH 6.7. Pluronic F127 addition increased the drug loading capacity and prolonged the sustained AME release from the fibers. The released AME significantly inhibited the in vitro growth of the breast cancer cells more than the non-tumorigenic cells, due to the induction of apoptosis, providing evidence for using pluronic F127-containing electrospun fibers for sustained and localized AME delivery to breast cancer cells.

Hyaluronic Acid-Functionalized Hollow Mesoporous Silica Nanoparticles as pH-Sensitive Nanocarriers for Cancer Chemo-Photodynamic Therapy

Hollow mesoporous silica nanoparticles (HMSNs) served as nanocarriers for transporting doxorubicin hydrochloride (DOX) and indocyanine green (ICG) and were incorporated into a pH-sensitive targeted drug delivery system (DDS). Boronate ester bonds were employed to link HMSNs and dopamine-modified hyaluronic acid (DA-HA), which acted as both the "gatekeeper" and targeting agents (HMSNs-B-HA). Well-dispersed HMSNs-B-HA with a diameter of about 170 nm was successfully constructed. The conclusion was drawn from the in vitro drug release experiment that ICG and DOX (ID) co-loaded nanoparticles (ID@HMSNs-B-HA) with high drug loading efficiency could sustain drug release under acidic conditions. More importantly, in vitro cell experiments perfectly showed that ID@HMSNs-B-HA could well inhibit murine mammary carcinoma (4T1) cells via chemotherapy combined with photodynamic therapy and accurately target 4 T1 cells. In summary, all test results sufficiently demonstrated that the prepared ID@HMSNs-B-HA was a promising nano-DDS for cancer photodynamic combined with chemotherapy.

Nonmechanical parfocal and autofocus features based on wave propagation distribution in lensfree holographic microscopy

Performing long-term cell observations is a non-trivial task for conventional optical microscopy, since it is usually not compatible with environments of an incubator and its temperature and humidity requirements. Lensless holographic microscopy, being entirely based on semiconductor chips without lenses and without any moving parts, has proven to be a very interesting alternative to conventional microscopy. Here, we report on the integration of a computational parfocal feature, which operates based on wave propagation distribution analysis, to perform a fast autofocusing process. This unique non-mechanical focusing approach was implemented to keep the imaged object staying in-focus during continuous long-term and real-time recordings. A light-emitting diode (LED) combined with pinhole setup was used to realize a point light source, leading to a resolution down to 2.76 μm. Our approach delivers not only in-focus sharp images of dynamic cells, but also three-dimensional (3D) information on their (x, y, z)-positions. System reliability tests were conducted inside a sealed incubator to monitor cultures of three different biological living cells (i.e., MIN6, neuroblastoma (SH-SY5Y), and Prorocentrum minimum). Altogether, this autofocusing framework enables new opportunities for highly integrated microscopic imaging and dynamic tracking of moving objects in harsh environments with large sample areas.

Synthesis of Radiolabeled Technetium- and Rhenium-Luteinizing Hormone-Releasing Hormone (99mTc/Re-Acdien-LHRH) Conjugates for Targeted Detection of Breast Cancer Cells Overexpressing the LHRH Receptor

Currently, ^186/188Re and ^99mTc are widely used radionuclides for cancer detection and diagnosis. New advancements in modalities and targeting strategies of radiopharmaceuticals will provide an opportunity to enhance imagery and detection of smaller colonies of cancer cells while lowering false-positive diagnoses. To understand the chemistry of agents derived from fac-[^99mTc(CO)₃(H₂O)₃]⁺ species, the nonradioactive [Re(CO)₃(H₂O)₃]⁺ analogue was used. We have designed and synthesized Re-Acdien-LHRH, Re-Acdien-peg-LHRH, and a radiolabeled ^99mTc-Acdien-LHRH (rhenium- and technetium-luteinizing hormone-releasing hormone) conjugates using a tridentate linker to detect cancers overexpressing the LHRH receptor. Re-Acdien-LHRH and Re-Acdien-peg-LHRH were synthesized from non-PEGylated and PEGylated LHRH-Acdien, respectively. Cellular uptake of the compounds ^99mTc-Acdien-LHRH, Re-Acdien-LHRH, and Re-Acdien-peg-LHRH was found to be significantly enhanced compared to that of untargeted ^99mTc alone and unlabeled [Re(CO)₃(H₂O)₃]⁺. In addition, the conjugate compounds showed no difference in cellular toxicity compared to untargeted ^99mTc alone or unlabeled [Re(CO)₃(H₂O)₃]⁺. Further, a competition assay using LHRH indicated selective targeting of Re-Acdien-peg-LHRH toward the LHRH receptor (p < 0.05) compared to that of [Re(CO)₃(H₂O)₃]⁺ alone. Together, our data show the design paradigm and synthesis of targeting radionuclides using the LHRH peptide. Our data suggests that utilizing the LHRH peptide can lead to selective targeting and diagnosis of breast cancers expressing the LHRH receptor.

Drug-encapsulated blend of PLGA-PEG microspheres: in vitro and in vivo study of the effects of localized/targeted drug delivery on the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is more aggressive and difficult to treat using conventional bulk chemotherapy that is often associated with increased toxicity and side effects. In this study, we encapsulated targeted drugs [A bacteria-synthesized anticancer drug (prodigiosin) and paclitaxel] using single solvent evaporation technique with a blend of FDA-approved poly lactic-co-glycolic acid-polyethylene glycol (PLGA_PEG) polymer microspheres. These drugs were functionalized with Luteinizing Hormone-Releasing hormone (LHRH) ligands whose receptors are shown to overexpressed on surfaces of TNBC. The physicochemical, structural, morphological and thermal properties of the drug-loaded microspheres were then characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Nuclear Magnetic Resonance Spectroscopy (NMR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Results obtained from in vitro kinetics drug release at human body temperature (37 °C) and hyperthermic temperatures (41 and 44 °C) reveal a non-Fickian sustained drug release that is well-characterized by Korsmeyer-Peppas model with thermodynamically non-spontaneous release of drug. Clearly, the in vitro and in vivo drug release from conjugated drug-loaded microspheres (PLGA-PEG_PGS-LHRH, PLGA-PEG_PTX-LHRH) is shown to result in greater reductions of cell/tissue viability in the treatment of TNBC. The in vivo animal studies also showed that all the drug-loaded PLGA-PEG microspheres for the localized and targeted treatment of TNBC did not caused any noticeable toxicity and thus significantly extended the survival of the treated mice post tumor resection. The implications of this work are discussed for developing targeted drug systems to treat and prevent local recurred triple negative breast tumors after surgical resection.