Treatment of cancer by systemic administration of Dbait molecules

A method of treating triple-negative breast cancer (TNBC) or chemoresistant lung cancer comprising the administration, by a parenteral systemic route selected from intraperitoneal and intravenous administration to a subject having a triple-negative breast cancer (TNBC) or chemoresistant lung cancer, a nucleic acid molecule of the following formula:

• wherein N is a deoxynucleotide, n is an integer from 15 to 195, the underlined N refers to a nucleotide having or not a modified phosphodiester backbone, L′ is a linker, C is the molecule facilitating endocytosis selected from a lipophilic molecule or a ligand which targets cell receptor enabling receptor mediated endocytosis, L is a linker, m is an integer being 0 or 1 and p is 1;
• wherein the nucleic acid is to be used without combined administration of any quinoline endosomolytic agent.