Lurbinectedin is a synthetic drug that has been developed for the treatment of cancer. According to the sources [1][2], Lurbinectedin targets specific cancer types, including small cell lung cancer (SCLC), ovarian cancer, and breast cancer. In preclinical studies, Lurbinectedin has shown efficacy in inhibiting the growth of these cancer types. It has also shown potential in treating other types of cancer, including neuroendocrine tumors, sarcomas, and leukemia.

Lurbinectedin is a selective inhibitor of RNA polymerase II, which is a key enzyme involved in the transcription of DNA into RNA. By inhibiting RNA polymerase II, Lurbinectedin blocks the transcription of certain genes that are essential for the survival and growth of cancer cells. This leads to the death of cancer cells and the inhibition of tumor growth.

In addition to its direct anticancer effects, Lurbinectedin has also been shown to have immunomodulatory effects. According to source [3], Lurbinectedin has been found to increase the expression of a protein called VISTA, which is an immune checkpoint protein that regulates the activity of T cells. By increasing the expression of VISTA, Lurbinectedin may help to enhance the antitumor immune response and improve the efficacy of immunotherapy in cancer treatment.

In conclusion, Lurbinectedin targets specific cancer types, including small cell lung cancer, ovarian cancer, and breast cancer, by inhibiting RNA polymerase II. It has also shown potential in treating other types of cancer and has immunomodulatory effects that may enhance the antitumor immune response. However, further research is needed to fully understand the mechanism of action and potential therapeutic applications of Lurbinectedin.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LURBINECTEDIN
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8988166/
[3] https://www.targetedonc.com/view/vista-emerges-as-a-promising-immunotherapy-target-in-cancer