Exosomes released by breast cancer cells under mild hyperthermic stress possess immunogenic potential and modulate polarization in vitro in macrophages.

Macrophages play a dual role in tumor initiation and progression, with both tumor-promoting and tumor-suppressive effects; hence, it is essential to understand the distinct responses of macrophages to tumor progression and therapy. Mild hyperthermia has gained importance as a therapeutic regimen against cancer due to its immunogenic nature, efficacy, and potential synergy with other therapies, yet the response of macrophages to molecular signals from hyperthermic cancer cells has not yet been clearly defined. Due to limited response rate of breast cancer to conventional therapeutics the development, and understanding of alternative therapies like hyperthermia is pertinent. In order to determine conditions corresponding to mild thermal dose, cytotoxicity of different hyperthermic temperatures and treatment durations were tested in normal murine macrophages and breast cancer cell lines. Examination of exosome release in hyperthermia-treated cancer cells revealed enhanced efflux and a larger size of exosomes released under hyperthermic stress. Exposure of naïve murine macrophages to exosomes released from 4T1 and EMT-6 cells posthyperthermia treatment, led to an increased expression of specific macrophage activation markers. Further, exosomes released by hyperthermia-treated cancer cells had increased content of heat shock protein 70 (Hsp70). Together, these results suggest a potential immunogenic role for exosomes released from cancer cells treated with mild hyperthermia.

Dual drug loaded liposome bearing apigenin and 5-Fluorouracil for synergistic therapeutic efficacy in colorectal cancer.

Multidrug-based combinatorial therapeutic regiments which target multiple pathways simultaneously are being utilized as a therapeutic strategy of choice due to reduction in toxicity profile and enhancement of therapeutic index of the individual drugs. 5-Fluorouracil is a clinically approved drug which has limited response rate in the realm of colorectal cancer amelioration, hence our study aims to improve its efficacy by aiming the simultaneous delivery of 5-Flurouracil and apigenin which is naturally occurring flavone abundantly present in fruit and vegetables through a single liposome to combat and control colorectal cancer effectively in-vitro and in-vivo. The liposomal nanocarrier bearing the anti-tumorigenic agent apigenin was designed in this study in order to improve the bioavailability of the flavone while at the same time achieve combinatorial drug regime with 5- Fluorouracil. This study reports the synthesis and production of a relatively robust dual drug-loaded liposomal formulation by modified thin film hydration method which substantially entraps both the drugs. Even though there have been reports of the combinatorial regimen involving apigenin and 5-Flurouracil our study reports the optimal molar ratio for effective synergistic therapeutic application of this drug combination to alleviate colorectal cancer. The cytotoxicity and cellular effects of individual, combinatorial free drugs and their liposomal counterparts tested against two human colon cancer cell lines revealed significantly higher cytotoxicity of the dual-drug liposomes. The dual-drug liposomes demonstrated enhanced inhibition of angiogenesis, better reduction in cell proliferation and increased apoptotic potential. Cell signaling studies indicating a significant upregulation of pAMPK and activity against downstream targets by dual drug liposomes suggested its role in the reversal of Warburg effect. The formulation was tested in a preclinical setting in nude mice tumor xenograft model and was found to have greater anti-neoplastic and anti-tumorigenic effect. The study indicated that the increased chemotherapeutic potential in vivo was due to the passive targeting achieved by the liposomal drug loaded nano-carrier and the synergistic effect of apigenin in 5-Fluorouracil treatment offers a new attractive alternative to enhance the therapeutic potency of drugs and paves way for potential clinical applications.

Second generation liposomal cancer therapeutics: transition from laboratory to clinic.

Recent innovations and developments in nanotechnology have revolutionized cancer therapeutics. Engineered nanomaterials are the current workhorses in the emerging field of cancer nano-therapeutics. Lipid vesicles bearing anti-tumor drugs have turned out to be a clinically feasible and promising nano-therapeutic approach to treat cancer. Efficient entrapment of therapeutics, biocompatibility, biodegradability, low systemic toxicity, low immunogenicity and ability to bypass multidrug resistance mechanisms has made liposomes a versatile drug/gene delivery system in cancer chemotherapy. The present review attempts to explore the recent key advances in liposomal research and the vast arsenal of liposomal formulations currently being utilized in treatment and diagnosis of cancer.

Poly(styrene-co-maleic acid)-based pH-sensitive liposomes mediate cytosolic delivery of drugs for enhanced cancer chemotherapy.

pH-responsive polymers render liposomes pH-sensitive and facilitate the intracellular release of encapsulated payload by fusing with endovascular membranes under mildly acidic conditions found inside cellular endosomes. The present study reports the use of high-molecular weight poly(styrene-co-maleic acid) (SMA), which exhibits conformational transition from a charged extended structure to an uncharged globule below its pK(1) value, to confer pH-sensitive property to liposomes. The changes in the co-polymer chain conformation resulted in destabilization of the liposomes at mildly acidic pH due to vesicle fusion and/or channel formation within the membrane bilayer, and ultimately led to the release of the encapsulated cargo. The vesicles preserved their pH-sensitivity and stability in serum unlike other polymer-based liposomes and exhibited no hemolytic activity at physiological pH. The lysis of RBCs at endosomal pH due to SMA-based liposome-induced alterations in the bilayer organization leading to spherocyte formation indicated the potential of these vesicles to mediate cytosolic delivery of bio-active molecules through endosome destabilization. The SMA-loaded liposomes exhibiting excellent cytocompatibility, efficiently delivered chemotherapeutic agent 5-Fluorouracil (5-FU) within colon cancer cells HT-29 in comparison to neat liposomes. This caused increased cellular-availability of the drug, which resulted in enhanced apoptosis and highlighted the clinical potential of SMA-based vesicles.