TURNing RanBP9 on NSCLC

Project Summary Remarkable advancements have been recently achieved in the treatment of Non-Small Cell Lung Cancer (NSCLC).

Targeted- and immune-therapy have produced spectacular patient remissions unimaginable only 5-years ago for this disease that is the number one cause of cancer related deaths in the developed world. Unfortunately, most patients do not achieve a durable response and are not cured.

Therefore, there is still an urgent need for new therapeutic targets and strategies to treat this devastating malignancy. The protein RanBP9 could be an attractive target for the treatment of NSCLC. RanBP9 protects NSCLC cells from stress induced by DNA damaging agents such as platinum based-drugs. The higher its levels, the worse the NSCLC patient response to platinum-based drugs.

This scaffold protein is significantly over-expressed in NSCLC cells when compared to the normal counterpart, which is expected on the basis of its anti- stress protective functions. Thus, a therapeutic window might be open to target RanBP9 without damaging normal cells. On the other hand, like numerous other potential targets for cancer therapy, RanBP9 is widely expressed.

Relatively high expression of RanBP9 is found in the brain and in the gonads, for example.

Therefore, before taking the idea of inactivating RanBP9 to the clinics, careful work needs to be done to better understand how RanBP9 protects cells from DNA damage.

Other than in cancer cells, it is particularly important to establish how this proteins works also in tumor associated macrophages (TAMs), which have been shown to promote tumorigenesis and resistance to therapy. To achieve these goals, whole organism modeling is necessary.

This proposal seeks to study by advanced proteomics the changes of the molecular interactions that RanBP9 shows in both normal and cancer cells when treated with cisplatin.

To distinguish the interactions of RanBP9 in cancer cells from those in the rest of the tumor microenvironment, we will use a new mouse line called RanBP9-TURN in which RanBP9-HA is turned off and RanBP9-V5 is turned on in cells where Cre is active.

In the first specific aim (Aim 1) of this proposal, we will study the interactions of RanBP9 in type II pneumocytes and in alveolar macrophages in a mouse model in which RanBP9 tag is switched from HA to V5 upon Cre-recombination.

This will establish the changes of the RanBP9-interactome following treatment with cisplatin in normal alveolar type II cells and alveolar macrophages.

In the second aim (Aim 2), we will study the dynamics of RanBP9 protein interactions in NSCLC cells and TAMs upon DNA damage. This will reveal the RanBP9-interactome changes in cancer cells and TAMs following DNA damage by cisplatin.

When accomplished, this study will add support to the pursue of mechanistically-designed therapies to treat NSCLC based on the targeting of RanBP9. It will also open new lines of investigation into unknown mechanisms of the cellular response to DNA damage.

Finally, the RanBP9-TURN will be a prototype in the field of mouse modeling for investigations into the tumor microenvironment.