将分子靶向药物整合到联合化疗中对于提高癌症治疗效果具有革命性意义。然而，要充分发挥这种方法的潜力，需要清楚地理解药物协同作用背后的遗传依赖性。虽然传统化疗药物之间的相互作用已得到充分探索，但分子靶向药物与传统化疗药物之间的相互作用仍然是癌症治疗的前沿。因此，我们利用强大的功能基因组学方法来解码基因组依赖性，从而推动胃腺癌中分子靶向药物/化疗组合的协同作用，满足胃癌治疗的关键需求。我们筛选了 15 种分子靶向药物/传统化疗药物之间的药理学相互作用在胃腺癌细胞中配对，并检查了将全基因组 CRISPR 筛选与基于 shRNA 的特征测定相结合的协同作用的基因组规模遗传依赖性。我们使用基于荧光和裂解依赖的细胞死亡动力学推断来验证细胞死亡的协同作用，并通过单基因敲除实验验证遗传依赖性。我们的组合筛选确定 SN-38/厄洛替尼是最强的药物对协同作用。功能基因组学分析揭示了 SN-38/厄洛替尼与 SN-38 相同的遗传依赖性特征。值得注意的是，SN-38/厄洛替尼诱导的细胞死亡增强和动力学改善归因于厄洛替尼抑制 ABCG2 的脱靶效应，而不是其对 EGFR 的靶向作用。 在强调主要药物的精准医疗时代目标占上风，我们的研究通过展示由脱靶依赖支撑的强大协同作用来挑战这一范式。进一步剖析协同作用背后的复杂遗传依赖性可以为开发更有效的胃癌治疗联合策略铺平道路。© 2024。作者。

Integrating molecular-targeted agents into combination chemotherapy is transformative for enhancing treatment outcomes in cancer. However, realizing the full potential of this approach requires a clear comprehension of the genetic dependencies underlying drug synergy. While the interactions between conventional chemotherapeutics are well-explored, the interplay of molecular-targeted agents with conventional chemotherapeutics remains a frontier in cancer treatment. Hence, we leveraged a powerful functional genomics approach to decode genomic dependencies that drive synergy in molecular-targeted agent/chemotherapeutic combinations in gastric adenocarcinoma, addressing a critical need in gastric cancer therapy.We screened pharmacological interactions between fifteen molecular-targeted agent/conventional chemotherapeutic pairs in gastric adenocarcinoma cells, and examined the genome-scale genetic dependencies of synergy integrating genome-wide CRISPR screening with the shRNA-based signature assay. We validated the synergy in cell death using fluorescence-based and lysis-dependent inference of cell death kinetics assay, and validated the genetic dependencies by single-gene knockout experiments.Our combination screen identified SN-38/erlotinib as the drug pair with the strongest synergism. Functional genomics assays unveiled a genetic dependency signature of SN-38/erlotinib identical to SN-38. Remarkably, the enhanced cell death with improved kinetics induced by SN-38/erlotinib was attributed to erlotinib's off-target effect, inhibiting ABCG2, rather than its on-target effect on EGFR.In the era of precision medicine, where emphasis on primary drug targets prevails, our research challenges this paradigm by showcasing a robust synergy underpinned by an off-target dependency. Further dissection of the intricate genetic dependencies that underlie synergy can pave the way to developing more effective combination strategies in gastric cancer therapy.© 2024. The Author(s).