Dynamics and visualization of MCF7 adenocarcinoma cell death by aptamer-C1q-mediated membrane attack

Area of Science:

• Biochemistry
• Immunology
• Oncology

Background:

• Breast cancer treatment often involves toxic therapies.
• Targeted therapies can improve treatment efficacy and reduce side effects.
• The complement system is a key component of innate immunity.

Purpose of the Study:

• To characterize the binding of a DNA aptamer (MUC1-5TR-1) to breast cancer cells.
• To evaluate the potential of an aptamer-C1q conjugate to induce cancer cell death.
• To explore a novel cancer treatment strategy by engaging the classical complement cascade.

Main Methods:

• Fluorescence confocal microscopy to visualize aptamer binding.
• Förster Resonance Energy Transfer (FRET) to detect membrane depolarization.
• Transmission electron microscopy (TEM) and immunogold labeling for MAC formation confirmation.
• In vitro cell culture of human breast adenocarcinoma (MCF7) cells.

Main Results:

• The DNA aptamer MUC1-5TR-1 successfully bound to the plasma membranes of MCF7 breast cancer cells.
• Aptamer binding initiated the classical complement pathway, leading to complement fixation.
• Evidence of membrane attack complex (MAC) formation and subsequent cell death was observed.
• Aptamer-mediated complement fixation resulted in cancer cell osmotic swelling and death.

Conclusions:

• DNA aptamers can be conjugated with C1q to target and kill cancer cells.
• This aptamer-based approach activates the patient's innate immune system for cancer therapy.
• This method offers a potentially less toxic and more targeted alternative to traditional cancer treatments like monoclonal antibodies.