Compositions and methods for treating cancer

A human K-Ras protein having a cysteine at residue 12, wherein said cysteine is covalently bonded to a compound, wherein said compound has the formula

• R1-L1-L2-L3-E,
• wherein
• R1 is a substituted or unsubstituted heteroaryl;
• L1 is substituted or unsubstituted heteroarylene;
• L2 is a bond;
• L3 is
• wherein
• f8 is an integer from 0 to 8;
• each R2C is independently oxo, halogen, —CXc3, —CN, —SO2Cl, —SOn3R10c, —SOv3NR7cR8c, —NHNH2, —ONR7cR8c, —NHC═(O)NHNH2, —NHC═(O)NR7cR8c, —N(O)m3, —NR7cR8c, —C(O)R9c, —C(O)—OR9c, C(O)NR7cR8c, —OR10c, —NR7cSO2R10c, —NR7c═(O)R9c, —NR7cC(O)—OR9c, —NR7cOR9c, —OCXc3, —OCHXc2, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• wherein
• two adjacent R2C substituents are optionally joined to form a substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• each R7c, R8c, R10c and R10c is independently hydrogen, halogen, —CF3, —CN, —OH, —NH2, —COOH, —CONH2, —NO2, —SH, —SO2Cl, —SO3H, —SO4H, —SO2NH2, —NHNH2, —ONH2, —NHC═(O) NHNH2, —NHC═(O)NH2, —NHSO2H, —NHC=(O)H, —NHC(O)—OH, —NHOH, —OCF3, —OCHF2, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl;
• R7c and R8c are optionally joined to form a substituted or unsubstituted heterocycloalkyl or substituted or unsubstituted heteroaryl;
• m3 and v3 are independently an integer from 1 to 2;
• n3 is an integer from 0 to 4;
• Xc is independently —Cl, —Br, —I, or —F;
• and,
• prior to covalently bonding to the cysteine 12,
• E is
• wherein each substituted alkyl, substituted heteroalkyl, substituted cycloalkyl, substituted heterocycloalkyl, substituted heteroaryl, substituted aryl is independently substituted with a substituent group.