Novel Drug Delivery Approaches for the Localized Treatment of Cervical Cancer

Cervical cancer (CC) is the fourth leading cancer type in females globally. Being an ailment of the birth canal, primitive treatment strategies, including surgery, radiation, or laser therapy, bring along the risk of infertility, neonate mortality, premature parturition, etc. Systemic chemotherapy led to systemic toxicity. Therefore, delivering a smaller cargo of therapeutics to the local site is more beneficial in terms of efficacy as well as safety. Due to the regeneration of cervicovaginal mucus, conventional dosage forms come with the limitations of leaking, the requirement of repeated administration, and compromised vaginal retention. Therefore, these days novel strategies are being investigated with the ability to combat the limitations of conventional formulations. Novel carriers can be engineered to manipulate bioadhesive properties and sustained release patterns can be obtained thus leading to the maintenance of actives at therapeutic level locally for a longer period. Other than the purpose of CC treatment, these delivery systems also have been designed as postoperative care where a certain dose of antitumor agent will be maintained in the cervix postsurgical removal of the tumor. Herein, the most explored localized delivery systems for the treatment of CC, namely, nanofibers, nanoparticles, in situ gel, liposome, and hydrogel, have been discussed in detail. These carriers have exceptional properties that have been further modified with the aid of a wide range of polymers in order to serve the required purpose of therapeutic effect, safety, and stability. Further, the safety of these delivery systems toward vital organs has also been discussed.

Long-Term Survival and Induction of Operational Tolerance to Murine Islet Allografts by Co-Transplanting Cyclosporine A Microparticles and CTLA4-Ig

One strategy to prevent islet rejection is to create a favorable immune-protective local environment at the transplant site. Herein, we utilize localized cyclosporine A (CsA) delivery to islet grafts via poly(lactic-co-glycolic acid) (PLGA) microparticles to attenuate allograft rejection. CsA-eluting PLGA microparticles were prepared using a single emulsion (oil-in-water) solvent evaporation technique. CsA microparticles alone significantly delayed islet allograft rejection compared to islets alone (p < 0.05). Over 50% (6/11) of recipients receiving CsA microparticles and short-term cytotoxic T lymphocyte-associated antigen 4-Ig (CTLA4-Ig) therapy displayed prolonged allograft survival for 214 days, compared to 25% (2/8) receiving CTLA4-Ig alone. CsA microparticles alone and CsA microparticles + CTLA4-Ig islet allografts exhibited reduced T-cell (CD4+ and CD8+ cells, p < 0.001) and macrophage (CD68+ cells, p < 0.001) infiltration compared to islets alone. We observed the reduced mRNA expression of proinflammatory cytokines (IL-6, IL-10, INF-γ, and TNF-α; p < 0.05) and chemokines (CCL2, CCL5, CCL22, and CXCL10; p < 0.05) in CsA microparticles + CTLA4-Ig allografts compared to islets alone. Long-term islet allografts contained insulin+ and intra-graft FoxP3+ T regulatory cells. The rapid rejection of third-party skin grafts (C3H) in islet allograft recipients suggests that CsA microparticles + CTLA4-Ig therapy induced operational tolerance. This study demonstrates that localized CsA drug delivery plus short-course systemic immunosuppression promotes an immune protective transplant niche for allogeneic islets.

Localized Drug Delivery Systems: An Update on Treatment Options for Head and Neck Squamous Cell Carcinomas

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers in the world, with surgery, radiotherapy, chemotherapy, and immunotherapy being the primary treatment modalities. The treatment for HNSCC has evolved over time, due to which the prognosis has improved drastically. Despite the varied treatment options, major challenges persist. HNSCC chemotherapeutic and immunotherapeutic drugs are usually administered systemically, which could affect the patient's quality of life due to the associated side effects. Moreover, the systemic administration of salivary stimulating agents for the treatment of radiation-induced xerostomia is associated with toxicities. Localized drug delivery systems (LDDS) are gaining importance, as they have the potential to provide non-invasive, patient-friendly alternatives to cancer therapy with reduced dose-limiting toxicities. LDDSs involve directly delivering a drug to the tissue or organ affected by the disease. Some of the common localized routes of administration include the transdermal and transmucosal drug delivery system (DDSs). This review will attempt to explore the different treatment options using LDDSs for the treatment of HNSCC and radiotherapy-induced damage and their potential to provide a better experience for patients, as well as the obstacles that need to be addressed to render them successful.

A biopolymeric mesh enriched with PLGA microparticles loaded with AT101 for localized Glioblastoma treatment

Current treatment strategies for glioblastoma (GBM) including surgical resection and adjuvant radio/chemotherapy result in a limited progression-free survival time of patients due to rapidly occurring tumor recurrences. The urgent need for more effective treatments has led to the development of different approaches for localized drug delivery systems (DDS) offering the advantages of reduced systemic side effects. A promising candidate for the treatment of GBMs is AT101, the R-(-)-enantiomer of gossypol due to its ability to induce apoptosis or trigger autophagic cells death in tumor cells. Here, we present an alginate-based drug-releasing mesh ladened with AT101-loaded PLGA microspheres (AT101-GlioMesh). The AT101-loaded PLGA microspheres were fabricated using an oil-in-water emulsion solvent evaporation method obtaining a high encapsulation efficiency. The drug-loaded microspheres enabled the release of AT101 over several days at the tumor site. The cytotoxic effect of the AT101-loaded mesh was evaluated using two different GBM cell lines. Strikingly, encapsulation of AT101 in PLGA-microparticles and subsequent embedding in GlioMesh resulted in a sustained delivery and more efficient cytotoxic effect of AT101 on both GBM cell lines. Thus, such a DDS holds promise for GBM therapy likely by preventing the development of tumor recurrences.

Recent Advancements in Metallic Drug-Eluting Implants

Over the past decade, metallic drug-eluting implants have gained significance in orthopedic and dental applications for controlled drug release, specifically for preventing infection associated with implants. Recent studies showed that metallic implants loaded with drugs were substituted for conventional bare metal implants to achieve sustained and controlled drug release, resulting in a desired local therapeutic concentration. A number of secondary features can be provided by the incorporated active molecules, including the promotion of osteoconduction and angiogenesis, the inhibition of bacterial invasion, and the modulation of host body reaction. This paper reviews recent trends in the development of the metallic drug-eluting implants with various drug delivery systems in the past three years. There are various types of drug-eluting implants that have been developed to meet this purpose, depending on the drug or agents that have been loaded on them. These include anti-inflammatory drugs, antibiotics agents, growth factors, and anti-resorptive drugs.

Localized, on-demand, sustained drug delivery from biopolymer-based materials

INTRODUCTION

Local drug delivery facilitiates higher concentrations of drug molecules at or near the treatment site to enhance treatment efficiency and reduce drug toxicity and other systemic side effects. However, local drug delivery systems face challenges in terms of encapsulation, delivery, and controlled release of therapeutics.

AREAS COVERED

We provide an overview of naturally derived biopolymer-based drug delivery systems for localized, sustained, and on-demand treatment. We introduce the advantages and limitations of these systems for drug encapsulation, delivery, and local release, as well as recent applications.

EXPERT OPINION

Naturally derived biopolymers like cellulose, silk fibroin, chitosan, alginate, hyaluronic acid, and gelatin are good candidates for localized drug delivery because they are readily chemically modified, biocompatible, biodegradable (with the generation of metabolically compatible degradation products), and can be processed in aqueous and ambient environments to maintain the bioactivity of various therapeutics. The tradeoff between the effective treatment dosage and the response by local healthy tissue should be balanced during the design of these delivery systems. Future directions will be focused on strategies to design tunable and controlled biodegradation rates, as well as to explore commercial utility in substituting biopolymer-based systems for currently utilized synthetic polymers for implants for drug delivery.

Synthesis of a novel monofilament bioabsorbable suture for biomedical applications

In this research, a novel bioabsorbable suture that is, monofilament and capable of localized drug delivery, was developed from a combination of natural biopolymers that where not previously applied for this purpose. The optimized suture formulation comprised of sodium alginate (6% wt/vol), pectin (0.1% wt/vol), and gelatin (3% wt/vol), in the presence of glycerol (4% vol/vol) which served as a plasticizer. The monofilament bioabsorbable sutures where synthesized via in situ ionic crosslinking in a barium chloride solution (2% wt/vol). The resulting suture was characterized in terms of mechanical properties, morphology, swelling, degradation, drug release, and biocompatibility, in addition to Fourier-transform infrared (FTIR) spectroscopy, Powder X-ray Diffraction (PXRD) and Differential Scanning Calorimetry (DSC) analysis. The drug loaded and non-drug loaded sutures had a maximum breaking strength of 4.18 and 4.08 N, in the straight configuration and 2.44 N and 2.59 N in the knot configuration, respectively. FTIR spectrum of crosslinked sutures depicted Δ9 cm^-1 downward shift for the carboxyl stretching band which was indicative of ionic interactions between barium ions and sodium alginate. In vitro analysis revealed continued drug release for 7 days and gradual degradation by means of surface erosion, which was completed by day 28. Biocompatibility studies revealed excellent hemocompatibility and no cytotoxicity. These results suggest that the newly developed bioabsorbable suture meets the basic requirements of a suture material and provides a viable alternative to the synthetic polymer sutures that are currently on the market.

Exploring potential formulation strategies for chemoprevention of breast cancer: a localized delivery perspective

This review focuses on the various formulation approaches that have been explored to achieve localized delivery in breast cancer. The rationale behind the necessity of localized drug delivery has been extensively reviewed. The review also emphasizes the various possible routes for achieving localized drug delivery. Particularly, different types of nanoplatforms like lipid-based drug carriers, polymeric particles, hydrogels, drug conjugates and other formulation strategies like microneedles and drug-eluting implants, which have been used to increase tumor retention and subsequently halt tumor progression, have been deliberated here. In addition, the significant challenges that may be encountered in the delivery of anticancer drugs and the aspects that require careful evaluation for effective localized delivery of chemotherapeutic agents have been discussed.

Diabetic Neuropathy Pain Management: A Global Challenge

BACKGROUND

Painful Diabetic Neuropathy (PDN) is a devastating condition affecting one in three people with diabetes.

INTRODUCTION

Keeping in mind the unceasingly escalating prevalence of diabetes mellitus worldwide, the number of PDN patients is also expected to rise with a reduced quality of life in patients and a staggering increase in healthcare costs. Despite relentless efforts and continuous research, the commercially available medications for relieving diabetic neuropathy pain are only partially effective with substantial side effects. This is, in part, due to our partial awareness of the underlying complexities causing PDN. The pathogenesis of PDN remains elusive because of the difficulty in obtaining damaged nerve samples and the absence of non-invasive methods to investigate the pathogenesis at different stages of disease progression. The purpose of this review was to describe pathogenesis, clinical manifestations and treatment options for PDN.

METHODS

The keywords relevant to the scope of this paper were put in electronic databases (PubMed and Google Scholar) to fetch the relevant data. The data were then analyzed and compiled.

RESULTS

A simplified overview of PDN for researchers new to the field has been provided in an attempt to clarify common confusions. The changes in skin structure and functions in response to diabetes, diabetic neuropathy and painful diabetic neuropathy are also discussed. The unavailability of an efficacious pain reliever for PDN stresses on the need for identifying the microenvironmental factors that are altered in PDN and manipulate them to tailor targeted theranostics.

CONCLUSION

In the end, we proposed to consider the altered skin structure, function and microenvironmental factors in the diabetic population for devising smart, targeted, stimuli-responsive treatment options to attain maximum pain relief with minimum side effects.

Injectable Thermosensitive Hydrogel Containing Erlotinib-Loaded Hollow Mesoporous Silica Nanoparticles as a Localized Drug Delivery System for NSCLC Therapy

Erlotinib (ERT), oral administration agents, is one of the most pivotal targeted drugs in the treatment of non-small cell lung cancer (NSCLC); however, its poor solubility, low oral bioavailability, and capricious toxicity limit broader clinical applications. In this paper, a novel injectable matrix is prepared based on hollow mesoporous silica nanoparticles (HMSNs) and thermosensitive poly(d,l-lactide)-poly(ethylene glycol)-poly(d,l-lactide) (PDLLA-PEG-PDLLA, PLEL) hydrogel to encapsulate and localize the sustained release of ERT for improved efficacy against NSCLC. The test-tube-inversion method shows that this ERT-loaded hydrogel composite (ERT@HMSNs/gel) presents as an injectable flowing solution under room temperature and transfers into a physically crosslinked non-flowing gel structure at physiological temperature.The ERT@HMSNs/gel composite shows a much longer intratumoral and peritumoral drug retention by in vivo imaging study. Notably, this injectable drug delivery system (DDS) provides an impressive balance between antitumor efficacy and systemic safety in a mice xenograft model. The novel ERT loaded HMSNs/gel system may be a promising candidate for the in situ treatment of NSCLC. Moreover, this study provides a prospective platform for the design and fabrication of a nano-scaled delivery system for localized anticancer therapies.

DoE Based Optimization and Development of Spray-Dried Chitosan-Coated Alginate Microparticles Loaded with Cisplatin for the Treatment of Cervical Cancer

BACKGROUND

The existing parenteral treatment of cervical cancer has high toxicity and poor distribution of drugs at the targeted site.

PURPOSE

To formulate localized mucoadhesive cisplatin loaded microparticles based formulation to treat cervical cancer so that enhanced therapeutics benefits with low toxicity could be achieved.

METHODS

Cisplatin loaded chitosan coated spray-dried microparticles were prepared by ionotropic gelation technique and optimized by Central Composite Design. The spray-dried uncoated and chitosan- coated microparticles were characterized for various parameters (Particle size, Morphology, Drug entrapment efficiency). In vitro drug release study was carried out in simulated vaginal fluids by dialysis membrane method. Ex vivo studies were carried out to evaluate the cytotoxic potential of the developed formulation by the MTT assay. A drug permeability study was performed by Franz diffusion cell using the vaginal tissue of Swiss Albino Mice.

RESULTS

All in vitro characterization parameters were found to be optimum. The in vitro release studies indicated a controlled release following the Higuchi model. The chitosan-coated microparticles were found to be more cytotoxic than uncoated microparticles and plain cisplatin solution. The chitosan-coated microparticles were found to be more permeable than uncoated microparticles. Finally, in vivo tumor regression and histopathological studies confirmed the significant decrease in tumor volume at different time intervals.

CONCLUSION

Thus, it can be concluded that mucoadhesive spray-dried microparticles could provide a favorable approach for localized delivery of the anticancer drug via vaginal route against cervical cancer with its enhanced effectiveness.

Peritumoral implantation of hydrogel-containing nanoparticles and losartan for enhanced nanoparticle penetration and antitumor effect

Background and purpose

Nanoparticle-loaded hydrogels – localized drug delivery devices containing a combination of therapeutic nanoparticles and implantable hydrogel – have been recipients of increased focus and interest for cancer treatment. However, it is difficult for the released nanoparticles to penetrate deeply into tumors because of the dense collagen network in the tumor extracellular matrix, which greatly limits their antitumor effect. We hypothesized that the implantation of a hydrogel loaded with both nanoparticles and losartan (Los) might enhance penetration because Los has been proven to effectively reduce collagen levels in various tumors. Herein, we developed a nanoparticle/Los-loaded hydrogel system and evaluated the intratumoral distribution and anticancer effect after peritumoral implantation of nanoparticles.

Methods

Fluorescent polystyrene nanoparticles (FPNPs, size ~100 nm) and Los were simultaneously encapsulated in a polyethylene glycol (PEG) hydrogel to form the FPNP/Los-loaded hydrogel. After peritumoral implantation in 4T1 tumor-bearing mice for 2 weeks, intratumoral distributions of FPNPs and collagen level were determined. Based on the results, liposomal doxorubicin (Doxil, ~100 nm) was subsequently substituted for FPNPs in the hydrogel. The cellular uptake and cytotoxicity of the Doxil/Los-loaded hydrogel were studied, and the in vivo antitumor efficacy after peritumoral implantation was evaluated.

Results

Compared with a standard FPNP-loaded hydrogel, the FPNP/Los-loaded hydrogel resulted in enhanced penetration and reduced collagen levels after implantation. Thereafter, the potential of a Doxil/Los-loaded hydrogel for cancer treatment was studied. Doxorubicin was released from the hydrogel and induced effective cytotoxicity against 4T1 cells. The Doxil/Los-loaded hydrogel showed synergistic antitumor effects in 4T1 tumor-bearing mice and was more effective at tumor inhibition than the Doxil-loaded hydrogel.

Conclusion

This study provides a proof of principle that the implantation of nanoparticles/Los-loaded hydrogel can increase the intratumoral distribution and antitumor efficacy of nanoparticles, owing to collagen depletion by Los. Future studies may build on this strategy for enhanced tumor penetration of nanoparticles.

Multifunctional Electrospun Nanofibers for Enhancing Localized Cancer Treatment

Localized cancer treatment is one of the most effective strategies in clinical destruction of solid tumors at early stages as it can minimize the side effects of cancer therapeutics. Electrospun nanofibers have been demonstrated as a promising implantable platform in localized cancer treatment, enabling the on-site delivery of therapeutic components and minimizing side effects to normal tissues. This Review discusses the recent cutting-edge research with regard to electrospun nanofibers used for various therapeutic approaches, including gene therapy, chemotherapy, photodynamic therapy, thermal therapy, and combination therapy, in enhancing localized cancer treatment. Furthermore, it extensively analyzes the current challenges and potential breakthroughs in utilizing this novel platform for clinical transition in localized cancer treatment.

Nanogel-Incorporated Injectable Hydrogel for Synergistic Therapy Based on Sequential Local Delivery of Combretastatin-A4 Phosphate (CA4P) and Doxorubicin (DOX)

Drug combination therapies employing dual-drug delivery systems offer an effective approach to reduce disadvantages of single-drug therapy, such as high dose and easy generation of drug resistance. Herein, a dual-drug delivery system based on nanogel-incorporated injectable hydrogel (NHG) was designed for sequential local delivery of combretastatin-A4 phosphate (CA4P) and doxorubicin (DOX) for antiangiogenesis and anticancer combination therapy. The injectable hydrogel was prepared for loading and quick release of hydrophilic drug CA4P, while the pH and redox stimuli-responsive nanohydrogels were incorporated into the injectable hydrogel by pH-responsive boronate ester bond for sustained long-term DOX delivery. The dual-drug-loaded NHG system released CA4P and DOX sequentially and exhibited high inhibitory activities on the cancer cell proliferation in vitro. It displayed superior therapeutic efficacy in vivo with only one single injection. Immunohistochemistry analyses suggested a synergistic therapeutic effect through tumor vascular collapse caused by CA4P and tumor cell apoptosis induced by DOX. The combination therapy of antiangiogenic and cytotoxic drugs using NHG delivery system offers a promising approach for improved cancer therapeutic efficacy. The nanogel-embedded injectable hydrogel can be employed as a universal drug carrier for local dual-drug delivery with sequential release behaviors by simple injection.

Intraperitoneal chemotherapy for ovarian cancer using sustained-release implantable devices

INTRODUCTION

Epithelial ovarian cancer (EOC) remains to be the most lethal of all gynecological malignancies mainly due to its asymptomatic nature. The late stages are manifested with predominant metastases confined to the peritoneal cavity. Although there has been a substantial progress in the treatment avenue with different therapeutic interventions, the overall survival rate of patients remain poor due to relapse and drug resistance.

AREAS COVERED

The pharmacokinetic advantages offered by intraperitoneal (IP) chemotherapy due to peritoneal-plasma barrier can be potentially exploited for EOC relapse treatment. The ability to retain high concentrations of chemo-drugs with high AUC peritoneum/plasma for prolonged durations in the peritoneal cavity can be utilized effectively through the clinical adoption of drug delivery systems (DDSs) which obviates the need for indwelling catheters. The metronomic dosing strategy could enhance anti-tumor efficacy with a continuous, low dose of chemo-drugs providing minimal systemic toxicity.

EXPERT OPINION

The development of a feasible, non-catheter based, IP DDS, retaining the peritoneal-drug levels, with less systemic levels could offer significant survival advantages as a patient-compliant therapeutic strategy. Suturable-implantable devices based on metronomic dosing, eluting drug in a sustained manner at low doses, could be implanted surgically post-debulking for treatment of refractory EOC patients.

Quorum-sensing Salmonella selectively trigger protein expression within tumors

Salmonella that secrete anticancer proteins have the potential to eliminate tumors, but nonspecific expression causes damage to healthy tissue. We hypothesize that Salmonella, integrated with a density-dependent switch, would only express proteins in tightly packed colonies within tumors. To test this hypothesis, we cloned the lux quorum-sensing (QS) system and a GFP reporter into nonpathogenic Salmonella. Fluorescence and bacterial density were measured in culture and in a tumor-on-a-chip device to determine the critical density necessary to initiate expression. QS Salmonella were injected into 4T1 tumor-bearing mice to quantify GFP expression in vivo using immunofluorescence. At densities below 0.6 × 10(10) cfu/g in tumors, less than 3% of QS Salmonella expressed GFP. Above densities of 4.2 × 10(10) cfu/g, QS Salmonella had similar expression levels to constitutive controls. GFP expression by QS colonies was dependent upon the distance to neighboring bacteria. No colonies expressed GFP when the average distance to neighbors was greater than 155 µm. Calculations of autoinducer concentrations showed that expression was sigmoidally dependent on density and inversely dependent on average radial distance. Based on bacterial counts from excised tissue, the liver density (0.0079 × 10(10) cfu/g) was less than the critical density (0.11 × 10(10) cfu/g) necessary to initiate expression. QS Salmonella are a promising tool for cancer treatment that will target drugs to tumors while preventing damage to healthy tissue.

An implantable active-targeting micelle-in-nanofiber device for efficient and safe cancer therapy

Nanocarriers have attracted broad attention in cancer therapy because of their ability to carry drugs preferentially into cancer tissue, but their application is still limited due to the systemic toxicity and low delivery efficacy of intravenously delivered chemotherapeutics. In this study, we develop a localized drug delivery device with combination of an active-targeting micellar system and implantable polymeric nanofibers. This device is achieved first by the formation of hydrophobic doxorubicin (Dox)-encapsulated active-targeting micelles assembled from a folate-conjugated PCL-PEG copolymer. Then, fabrication of the core-shell polymeric nanofibers is achieved with coaxial electrospinning in which the core region consists of a mixture of poly(vinyl alcohol) and the micelles and the outer shell layer consists of cross-linked gelatin. In contrast to the systematic administration of therapeutics via repeatedly intravenous injections of micelles, this implantable device has these capacities of greatly reducing the drug dose, the frequency of administration and side effect of chemotherapeutic agents while maintaining highly therapeutic efficacy against artificial solid tumors. This micelle-based nanofiber device can be developed toward the next generation of nanomedicine for efficient and safe cancer therapy.

Steroid-eluting sinus implant for in-office treatment of recurrent polyposis: a pharmacokinetic study

BACKGROUND

Long-term use of systemic glucocorticoid therapy has been associated with hypothalamic-pituitary-adrenal axis suppression and other systemic adverse events. This pharmacokinetic study evaluated the systemic safety and performance of a bioabsorbable sinus implant that gradually releases 1350 μg of mometasone furoate directly to the sinus mucosa.

METHODS

A prospective, single-center study treating 5 adult patients with recurrent polyposis after bilateral total ethmoidectomy. Each patient received 2 steroid-releasing implants in-office under local/topical anesthesia. Plasma concentrations of mometasone furoate and cortisol were determined before placement and through 30-day follow-up, which also included endoscopic grading and patient-reported outcomes.

RESULTS

Five patients (mean age 46.2 ± 9.2 standard deviation [SD] years; 60% male) underwent successful placement in all 10 ethmoid sinuses. There were no serious adverse events. The plasma concentrations of mometasone furoate were generally below the lower limit of quantification (LLOQ) of the assay (30 pg/mL). Cortisol concentrations at follow-up ranged from 3.9 to 5.7 mg/dL compared to 4.7 mg/dL at baseline. At 1 month, there was a significant improvement in bilateral polyp grade (p = 0.037), nasal obstruction score (p = 0.002), and 22-item Sino-Nasal Outcome Test (SNOT-22) (p = 0.010) compared to baseline.

CONCLUSION

The reported 100% placement success, negligible systemic exposure to mometasone furoate released over time, lack of adrenal suppression, and the absence of serious adverse events suggest that the implant provides a valid and safe option for the in-office treatment of recurrent polyposis. Randomized, controlled, blinded clinical studies are underway to provide further evidence of safety and efficacy.

Identification of Staphylococcus aureus α-hemolysin as a protein drug that is secreted by anticancer bacteria and rapidly kills cancer cells

Targeted bacterial delivery of anticancer proteins has the ability to overcome therapeutic resistance in tumors that limits the efficacy of chemotherapeutics. The ability of bacteria to specifically target tumors allows for delivery of aggressive proteins that directly kill cancer cells and cannot be administered systemically. However, few proteins have been tested for this purpose. To identify effective molecules, we systematically sorted proteins that have been shown to cause mammalian cell death. The genes for five proteins were selected and cloned into Escherichia coli and Salmonella. Supernatant from cultures of the transformed bacteria was applied to flasks of MCF-7 mammary carcinoma cells to identify proteins that (1) were expressed, (2) secreted, and (3) rapidly killed cancer cells. Time-lapse images were taken to visualize mammalian cell morphology. Of the investigated proteins, α-hemolysin from Staphylococcus aureus (SAH) was the most promising because it was secreted, caused trauma to cellular membranes, and induced oncosis in 18 min. After exposure for 6 h, SAH decreased cell viability by 90%. In comparison, the positive control, Pseudomonas aeruginosa exotoxin A (PEA), required 11 days to achieve a similar effect, when administered at 3,000 times its LC50 . The maximum death rate induced by SAH was calculated to be a reduction in cell viability of 7.1% per min, which was 200-fold faster than the PEA control. Two proteins, Dermonecrotic Toxin and Phospholipase C were active when extracted from the bacterial cytoplasm but were not secreted. This investigation revealed for the first time SAH as a potent anticancer drug for delivery by bacteria because of its ability to be secreted in a fully functional form and aggressively kill cancer cells.