LOW MICRO-ENVIRONMENTAL O2 TENSION AND PH AS HALLMARKS OF CANCER

[Mr. God of Cars]

The presence of areas with low (<1%) O2 tension is associated with increased metastasis and poor patient survival [5], giving rise to the notion that hypoxia is a hallmark of malignant cancer. The discovery that hypoxia alters cell biology [6] (e.g. via hypoxia-inducible factor HIF1α [7]) offered a mechanism for adaptive changes, such as the switch-over to glycolytic metabolism (Warburg effect; [8]). Tumour hypoxia has since become a topic of considerable research, achieving promising outcomes with respect to understanding aetiology, improving diagnosis and developing treatments [6,9]. Among other micro-environmental factors specifically identified in tumours, extracellular acidity has emerged as another cancer hallmark [10–12]. Contrary to initial expectations, the intracellular compartment was shown to be alkaline [13] despite low extracellular pH (pHe). Other than in solid tumours, this trans-membrane [H+] distribution (acidic extracellularly/alkaline intracellularly) is not commonly observed in tissue. Two questions have emerged in response to these pioneering studies: firstly, how do solid tumours produce low pHe yet are able to maintain pHi within favourable limits, and, secondly, how does this trans-membrane pH-distribution affect disease progression?

From: (The chemistry, physiology and pathology of pH in cancer).

 

[meatbag]

extracellular acidity has emerged as another cancer hallmark [10–12]. Contrary to initial expectations, the intracellular compartment was shown to be alkaline

"
Herb Doctor: The popular theory is stated that cancer cells like an acidic environment. It sounds like if a cell is stressed it likes an alkaline environment and that sounds almost exactly the opposite.

RP: Well, it shifts internally to become alkaline when it's stressed but the produced lactic acid accumulates in it's environment and that's where the acid is, in the surroundings and then it shows up in the blood."

"And if you stress a cell that isn't getting enough carbon dioxide, or stress it in any way - radiation, not enough oxygen, not enough of any of the things that it needs - the cell becomes activated and shifts to the alkaline because it can't make carbon dioxide to acidify itself and it begins producing lactic acid very inefficiently. And the thing about lactic acid is that sugar instead of being oxidized all the way to carbon dioxide comes to the point of pyruvic acid and instead of that being oxidized, the cell reduces the pyruvic acid to lactic acid by taking some of the energy substance that was produced in this metabolism, wasting it to get rid of the electrons so that this NADH, NAD can go back and become reduced again and produce more of the conversion of pyruvic to lactic acid. And in that process, the lactic acid is taking protons out of the cell and is raising the pH of the cell as the conversion of pyruvic acid to lactic acid increases the pH of the cell, just the opposite of what the production of carbon dioxide is doing. So the stressed cell becomes alkaline."

"Herb Doctor: So that's a stressed cell. And does lactic acid play a big part in cancer as well?

RP: Yeah. It not only acidifies the environment, which in itself could be actually protective if it was acidified by carbon dioxide, but it happens that the lactic acid acts as a signal to do all of the things associated with cancer, such as stimulating the growth of new blood vessels so that the inflammation continues. It signals a lot of inflammatory changes like vasodilation and formation of new blood vessels and the release of carbon monoxide and nitric oxide, lots of things producing free radicals and injury. So the lactic acid is functioning as a local poisoner and inflammatory agent. The acidity that it produces is a sign that something is wrong but it isn't the acidity in the tumor that's harmful because the tumor itself is internally alkaline."

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Acidity and Alkalinity; Acidity and Alkalinity

 

[Mr. God of Cars]

Meatbag, I will ask you a question: Was your reply complementary or non-complementary to my post, because I don't see how they differ from the facts (Facts: cancer cell and its environment is, respectively, alkaline and acidic)?

 

[meatbag]

Meatbag, I will ask you a question: Was your reply complementary or non-complementary to my post, because I don't see how they differ from the facts (Facts: cancer cell and its environment is, respectively, alkaline and acidic)?

What I really meant to say was.........