Targeting the replisome with transduced monoclonal antibodies triggers lethal DNA replication stress in cancer cells

Area of Science:

• Molecular Biology
• Cancer Research
• Cell Biology

Background:

• Chemical inhibition of the DNA damage response (DDR) can induce cancer cell death.
• The sufficiency of replisome protein blockade in overcoming DDR remains unclear.

Purpose of the Study:

• To investigate if blocking DNA elongation via transduced antibodies against PCNA is sufficient to induce cancer cell death.
• To explore the potential of antibody-based therapies in overcoming resistance to conventional chemical inhibitors.

Main Methods:

• Development and transduction of monoclonal antibodies against PCNA into cancer cells.
• Co-delivery of anti-PCNA siRNA and antibody fragments (Fab).
• Super-resolution microscopy to analyze nuclear changes and histone H2AX foci.
• Assessment of cell morphology, nuclear size, and senescence-like phenotypes.

Main Results:

• Transduced anti-PCNA antibodies inhibited nucleoside analogue incorporation and induced cell flattening with significant nuclear enlargement.
• Co-delivery with siRNA led to cell death, characterized by increased phosphorylated histone H2AX foci.
• PCNA gene disruption or Fab fragment delivery induced a senescence-like phenotype.
• Antibody treatment effectively impacted primary melanoma and leukemia cells resistant to chemical inhibitors.

Conclusions:

• Transduced antibodies can effectively trigger lethal DNA replication stress by targeting key replisome proteins.
• This antibody-mediated approach offers a novel strategy to eliminate cancer cells, including those resistant to chemical treatments.
• Targeting the replisome directly represents a promising therapeutic avenue in oncology.