Data for: A cell surface-binding antibody atlas nominates a MUC18-directed antibody-drug conjugate for targeting melanoma

Recent advances in targeted therapy and immunotherapy have substantially improved the treatment of melanoma. However, therapeutic strategies are still needed for unresponsive or treatment-relapsed melanoma patients. To discover antibody-drug conjugate (ADC)-tractable cell surface targets for melanoma, we developed an atlas of melanoma cell surface binding antibodies (pAbs) using a proteome-scale antibody array platform (PETAL). Target identification of pAbs led to development of melanoma cell killing ADCs against LGR6, TRPM1, ASAP1, and MUC18, among others. MUC18 was overexpressed in both tumor cells and tumor-infiltrating blood vessels across major melanoma subtypes, making it a potential dual-compartment and universal melanoma therapeutic target. AMT-253, an MUC18-directed ADC based on topoisomerase I inhibitor exatecan and a self-immolative T moiety, had a higher therapeutic index compared to its microtubule inhibitor-based counterpart and favorable pharmacokinetics and tolerability ..., PETAL monoclonal antibody arrays (60,000 mAb printed on 2 x slides) were prepared as previously reported. Melanoma cells GAK, HMVII and A375 (1-2x107) suspended in 2 ml 1x PBS were first labeled with DNA dye Syto-62 (ThermoFisher, S11344) at 1:10000 ratio for 10 minutes. Labeled cells were then incubated with PETAL array for 30 minutes at 37°C without shaking (0.5-1x107 cells per array). After a gentle washing step in 1x PBS buffer to remove unbound cells, the slides were scanned by GenePix 4200A (Modecular Device). Images were analyzed by GenePix Pro software (GenePix Pro, RRID:SCR_010969). , , ***

# PETAL screening on melanoma cells

***

An antibody array platform (PETAL) was used to screen overexpressed surface target on melanoma cells

## Description of the data and file structure

The antibody arrary was screened against 3 different cell lines: GAK, HMVII, and A375.

For each cell line, there was two antibody arrary slides: A1 and A2.

See the Methods sections for details.

### The list below describes each column of data in the Results file:

| **Block** | the block number of the feature. |
| :---- | :------------------------------- |
| **Column** | the column number of the feature. |
| **Row** | the row number of the feature. |
| **Name** | the name of the feature derived from the Array List (up to 40 characters long, contained in quotation marks). |
| **ID** | the unique identifier of the feature derived from the Array List (up to 40 characters long, contained in quotation marks). |
| **X** | the X-coordinate in µm of the center of the feature-indicator associated wit...