**7.3 Actin binding proteins**

Actin cytoskeleton is a dynamic network of filaments, which is associated with several proteins, plays an important role in cell shape, motility and signal transduction, this further switches on the other processes like embryonic development, tissue repair, immune response and tumor formation. However in cancer biology, actin cytoskeleton and actin associated proteins undergo modification in transformed tumor cell and impose ability to adhere and metastasize. It can be used for developing new chemotherapeutic agents. Actin targeting molecules could disrupt actin by destabilizing the filaments or induce hyperpolymerization [62].

#### **7.4 Hectochlorin**

Marine cyanobacteria *Lyngbya majuscula* provided a suitable source for the isolation of Hectochlorin. It was a potent antifungal agent. It showed activity towards

**Figure 8.** *Image showing* Dolabella auricularia.

the Ptk2 cells derived from *Potorous tridactylus*, when treated with hectochlorin showed an increase in the number of the binucleated cells as a result of arresting the cytokinesis process. This peptide is very similar in action to jasplakinolode, in promoting hyperpolymerization of actin. Main difference that lies in between hectochlorin and jasplakinolode is that former can displace fluorescently labeled phalloidin from actin polymers, while the latter have two distinct interactions with actin. Hectochlorin, also strong potential towards the cell lines in the colon, melanoma, ovarian and renal sub-panels [63]. It showed a flat response curve against most cell lines, a specific activity of the compounds that are anti-proliferative but not directly cytotoxic [60].
