It is human nature to be selfish/greedy. That fact doesn't really excuse us for being that way or allow us to continue that behaviour without consequence though. Anyways, money (currency) is a major trade. We use it to get necessary recourse and unnecessary products. We can also use it as trade for someone to perform a task. Due to the fact it is a highly desired trade source people often lose their minds and do whatever it takes to attain as much as they can. And for those who are successful to become wealthy (or born in a wealthy family) are highly prone to get high off of their wealth. By that I mean they go on a power rush. They have the money to spend on things they desire (cars, houses, etc.), attract people/multiple relations (let's face it, as I stated already, numerous people will do whatever they can to achieve wealth) and do pretty much what they desire (numerous times celebrities and other wealthy folk pay their way out of jail or prison). So in a sense, yes money/wealth can cause you to lose ethical reasoning (and even your morals).
I am kind of caught in between as I think it depends on the person you are. I could vote no and yes on this matter. However, I will mostly say no on this one because what most people fail to recognize is the people who use that money for bad had bad ethics and bad intentions to begin with, they would of done horrible things with or without money, you don't need money to do bad things. Money just basically adds to the equation of a crappy person. I think if you are naturally good though, that shouldn't be a problem or an issue, the only issue a good person would have with all the money in the world is the bad people wont let the good person just do their thing to begin with. There is no such thing as the good die young because the good only die young because bad people wont let them be. Its kind of like religion (and I am religious myself I just have different views) that if you have to have a bible to tell yourself a your a good person, then you probably shouldn't have that bible. Just my two cents though, take this lightly as my opinion and not facts. I know some people are bad out there but I firmly believe that bad people just do bad things to begin with, money is just an illusion to their power.