This work investigates the dynamic service caching, computing, and communication (3C) resource optimization for edge-cloud networks, where users, edge node, and cloud all having 3C capabilities. Based on the developed hierarchical network model, we propose a two-timescale problem aiming to minimize energy consumption under queue stability and latency and reliability constraints. A 3C resource optimization approach is then developed based on the formulated problem and Lyapunov optimization. Simulation results show that our approach can outperform the reference schemes in terms of average service delay and reliability, and can effectively provide tradeoff between energy consumption and service delay.