Hedgehog-producing cancer cells respond to and require autocrine Hedgehog activity

Area of Science:

• Oncology
• Molecular Biology
• Cancer Signaling Pathways

Background:

• Smoothened (SMO) pathway antagonists are under investigation as anticancer drugs.
• Current models propose these drugs inhibit tumor growth by targeting Hedgehog (HH) signaling in stromal cells, not cancer cells.
• The role of autocrine HH signaling in cancer cells is considered negligible, with SMO antagonist effects attributed to off-target actions.

Purpose of the Study:

• To investigate the role of intrinsic Hedgehog (HH) signaling in the tumorigenic properties of HH-producing cancer cells.
• To determine if reducing HH signaling affects HH target gene expression within cancer cells.
• To challenge the established dogma regarding the lack of autocrine HH signaling in HH-dependent cancers.

Main Methods:

• Analysis of tumorigenic properties of lung cancer cells based on their intrinsic HH pathway activity.
• Experimental reduction of HH signaling within cancer cells.
• Assessment of HH target gene expression following HH signaling modulation.

Main Results:

• Tumorigenic properties of lung cancer cells were found to be dependent on their intrinsic HH pathway activity.
• Reduced HH signaling in these tumor cells led to decreased expression of HH target genes.
• The findings indicate that autocrine HH signaling influences cancer cell behavior.

Conclusions:

• The study questions the prevailing dogma that autocrine HH signaling does not play a role in HH-dependent cancers.
• Intrinsic HH pathway activity in cancer cells directly influences their tumorigenic potential.
• These findings suggest novel therapeutic strategies targeting the intrinsic HH pathway in cancer cells.