TED-Ed:認識癌細胞與癌症治療

2012⋅12⋅23
TED-Ed:認識癌細胞與癌症治療
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2012⋅12⋅23
TED-Ed:認識癌細胞與癌症治療

癌症,這個人人聞之喪膽的疾病,在現代社會中顯得越來越常見。我們都害怕生活鐘琳琅滿目的加工食品、電子用品、工業建設、或是環境污染會把癌症帶入你我的生命中,但恐懼與拒斥並不會因此保護我們免於傷害!本次的 TED-Ed 便運用溫暖近人的毛線與穀類為素材來表現組織與細胞的各式樣態,使我們暫時拋開恐懼,冷靜且客觀的認識它的形成、以及對付它的方式!


從生物學的角度來說,要認識癌症和癌症治療方式就必須先認識細胞的生成。我們都知道,單一細胞以倍數成長,而癌細胞其實就是受到環境刺激而突變的細胞。通常,身體跟從著「多數決」的原則,會自動發現不尋常的細胞並予以消除;但當變異細胞的數量到達某一程度,身體便以為這些細胞也是正常生物體的一部份了!

cell


對付癌症的治療方式有三種類型,而醫師便依照癌細胞的位置和擴散速度決定治療方式:

  1. 手術切除:適用於腫瘤生長緩慢且只生長在單一部位
  2. 放射治療:腫瘤生長快速且已侵略周圍的組織
  3. 化學治療:罹癌器官遍佈全身

放射與化學治療鎖定的細胞都不只是癌細胞而已,而是包含了癌細胞與正常細胞,而藥物攻擊細胞的時機其實就是每一次(不論好壞的)細胞進行分裂之時。

therapy


舉例來說,健康的肝細胞、頭髮細胞、與癌細胞三者分裂的速度不同,引發藥物生效的頻率也因而不同:癌細胞生長的速度異常的快,也因此引發最多次藥物的作用、健康的肝細胞只在器官有損傷時進行複製、但像頭髮細胞這種無時無刻都在分裂增生的細胞來說,麻煩可就大了。藥物治療所引發的掉髮、起疹子、噁心、嘔吐、疲倦、體重減輕、疼痛等副作用,就是因為皮膚、內臟、及血液的細胞分裂的次數非常頻繁、所受到的藥物攻擊也十分強烈。

cells


然而,這些副作用都將只是一個過程,若及早發現、及早開始治療,癌症並不是無法治療的絕症。因此,為了維護你我的健康,除了平時注意飲食和生活習慣、嚴格為環境污染把關、也不要忘記定期做健康檢查,不讓任何突變的細胞有搗亂的機會!

healthy


註:

由於TED-Ed官方還在進行網站與影片的中文化,目前尚未開放有中文字幕的TED-Ed影片。如果對完整中文稿有興趣,以下是我們為您準備的影片中英對照稿,敬請參考:

We all start life as one single cell. Then that cell divides. And we are two cells, then four, then eight. Cells form tissues, tissues form organs, organs form us. These cell divisions, by which we go from a single cell to 100 trillion cells, are called growth. And growth seems like a simple thing because when we think of it, we typically think of someone getting taller or, later in life, wider, but to cells, growth isn't simple.

所有的生命起源都來自一個細胞。他分裂成兩個、四個、八個…細胞逐漸形成組織,組織形成器官,而器官便構成了我們的身體。單一細胞逐漸分裂成十兆個細胞的過程就叫做「成長」。提及這個詞,我們總是想得很簡單:一般都會想到某人長高了、變壯了,但對細胞來說,成長可不是這麼簡單的一件事。

Cell division is an intricate chemical dance that's part individual, part community-driven. And in a neighborhood of 100 trillion cells, some times things go wrong. Maybe an individual cell's set of instructions, or DNA, gets a typo, what we call a mutation. Most of the time, the cell senses mistakes and shuts itself down, or the system detects a troublemaker and eliminates it. But, enough mutations can bypass the fail-safes, driving the cell to divide recklessly. That one rogue cell becomes two, then four, then eight. At every stage, the incorrect instructions are passed along to the cells' offspring.

細胞分裂就像一場繁複的化學舞蹈,一部份是獨立運作,某部分又由群體所主導。在一個擁有十兆個居民的細胞群體中,有時難免會出些差錯。我們所稱的「突變」就是細胞中控制著生命密碼的 DNA 出了錯。大部份的時候,細胞會偵測出這些變異並自行消滅它,或者系統也會偵測並消除掉突變的細胞;然而,突變的數量若是夠多,這些變異的細胞就可能會通過這些防禦機制,恣意地進行細胞分裂。一個突變的細胞就這樣分裂成兩個、四個、八個… 。每一個階段,細胞中的錯誤指令就被傳了下去。

Weeks, months, or years after that one rogue cell transformed, you might see your doctor about a lump in your breast. Difficulty going to the bathroom could reveal a problem in your intestine, prostate, or bladder. Or, a routine blood test might count too many white cells or elevated liver enzymes. Your doctor delivers the bad news: it's cancer.


隨著時間推移,這個細胞也許就形成了你乳房中的腫塊;如廁時的困難可能肇因於腸子、前列腺、或是膀胱;或者,進行健康檢查時可能檢驗出血液中過多的白血球或升高的肝臟酵素。此時,醫生便宣布了一個壞消息:這是癌症。


From here your strategy will depend on where the cancer is and how far it's progressed. If the tumor is slow-growing and in one place, surgery might be all you need, if anything. If the tumor is fast-growing or invading nearby tissue, your doctor might recommend radiation or surgery followed by radiation. If the cancer has spread, or if it's inherently everywhere like a leukemia, your doctor will most likely recommend chemotherapy or a combination of radiation and chemo. Radiation and most forms of chemo work by physically shredding the cells' DNA or disrupting the copying machinery. But neither radiation nor chemotherapeutic drugs target only cancer cells. Radiation hits whatever you point it at, and your blood stream carries chemo-therapeutics all over your body.


情況發展至此,你就得依照癌細胞的位置以及生長狀況對症下藥。若腫瘤生長緩慢且只生長在某個部位,動個手術也許就能解決掉它;若腫瘤生長快速且侵略了周圍的組織,醫師也許會建議使用放射治療、或是先進行手術切除後再做放射治療;若癌細胞已經擴散,或者罹癌的部位本身就是遍佈全身(例如血癌),醫生可能會建議進行化學治療、或是放射治療與化療同步進行。放射治療與大部份的化療會破壞掉細胞的 DNA 、或搗亂細胞複製的程序,但這兩種治療鎖定的細胞都不只是癌細胞而已。放射治療會攻擊所有放射線照射到的部位,而血液則會把化學療程的藥物帶至全身。


So, what happens when different cells get hit? Let's look at a healthy liver cell, a healthy hair cell, and a cancerous cell. The healthy liver cell divides only when it is stressed; the healthy hair cell divides frequently; and the cancer cell divides even more frequently and recklessly.

那麼,癌細胞與正常細胞對於這些治療的反應各是如何呢?讓我們來看看健康的肝細胞、頭髮細胞、與癌細胞吧。健康的肝細胞只在器官有所損傷時進行複製,頭髮細胞則是無時無刻都在分裂增生,而癌細胞生長的速度比起正常細胞更快、更瘋狂。

When you take a chemotherapeutic drug, it will hit all of these cells. And remember that the drugs work typically by disrupting cell division. So, every time a cell divides, it opens itself up to attack, and that means the more frequently a cell divides, the more likely the drug is to kill it.

當你進行化療時,藥物會攻擊所有細胞,而藥物的作用是搗亂細胞分裂的程序。也就是說,每一次細胞開始分裂時就是藥物產生作用的時候,而分裂頻率越高的細胞就會引發越多次的藥物攻擊。

So, remember that hair cell? It divides frequently and isn't a threat. And, there are other frequently dividing cells in your body like skin cells, gut cells, and blood cells. So the list of unpleasant side effects of cancer treatment parallels these tissue types: hair loss, skin rashes, nausea, vomiting, fatigue, weight loss, and pain. That makes sense because these are the cells that get hit the hardest.

記得頭髮細胞嗎?它分裂的很快、但並不對身體造成威脅,且身體中存在著其他分裂頻繁的細胞,像是皮膚細胞、內臟細胞、血液細胞。因此,治療癌症時常見的副作用就反應在這些部位,像是伴隨而來的掉髮、起疹子、噁心、嘔吐、疲倦、體重減輕、疼痛等,原因正是因為這些細胞分裂的次數非常頻繁。

So, in the end, it is all about growth. Cancer hijacks cells' natural division machinery and forces them to put the pedal to the metal, growing rapidly and recklessly. But, using chemotherapeutic drugs, we take advantage of that aggressiveness, and we turn cancer's main strength into a weakness.


總結來說,癌症與「成長」緊密相連。癌症綁架了細胞自然的分裂機制、逼迫它們任意的胡亂成長。而藉由化療的藥物,我們就能控制它侵犯細胞的速度,將癌細胞分裂快速的特性轉變成它最大的弱點。


來源   >   撰稿及翻譯:劉耘   |   影片:How do cancer cells behave differently from healthy ones? - George Zaidan

發佈於2012⋅12⋅23
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