Survivin is a protein found within the human body, playing a unique dual role. Its name, derived from “survival,” hints at its function in cellular processes. This protein is present in various tissues, and its actions are carefully regulated under normal physiological conditions. Scientists are particularly intrigued by how this single protein can be involved in both maintaining healthy cellular life and contributing to disease states.
Survivin’s Role in Healthy Cells
In healthy cells, survivin performs specific, regulated functions fundamental for normal cellular processes. One primary role involves cell division, known as mitosis. Survivin associates with the mitotic spindle, a structure that helps accurately separate chromosomes into two daughter cells. This ensures proper segregation of genetic material during cell replication.
Survivin also possesses anti-apoptotic properties. Apoptosis is programmed cell death that removes damaged or unnecessary cells, maintaining tissue homeostasis. Survivin helps inhibit this process, allowing cells to complete their normal life cycles without premature demise. Its presence is notable during embryonic development, where controlled cell survival and proliferation are necessary for tissue and organ formation.
In adult tissues, survivin is generally expressed at low levels, but can be transiently upregulated in certain proliferating cells, such as those in the bone marrow or intestinal crypts.
Survivin’s Contribution to Cancer
The normal functions of survivin become dysregulated in cancer, where its overexpression contributes significantly to tumor development and progression. Survivin is found at abnormally high levels in most human cancers, including lung, breast, colon, and prostate cancers. This widespread overexpression makes it a common feature of malignant transformation across various tissue types.
The elevated presence of survivin allows cancer cells to evade programmed cell death (apoptosis), a natural defense mechanism against abnormal cells. By inhibiting apoptosis, survivin promotes uncontrolled cell proliferation, enabling tumor growth and expansion.
Furthermore, survivin’s overexpression in cancer cells confers resistance to conventional therapies, such as chemotherapy and radiation. Many anti-cancer treatments work by inducing apoptosis in tumor cells. However, high levels of survivin counteract these effects, allowing cancer cells to survive treatment and continue to grow. This resistance poses a significant challenge in cancer therapy.
The protein also plays a role in angiogenesis, the formation of new blood vessels that supply tumors with nutrients, further supporting their aggressive growth and spread.
Targeting Survivin in Cancer Treatment
Given its significant role in cancer cell survival and resistance, survivin has emerged as a promising target for novel cancer therapies. The strategy involves inhibiting survivin’s function to re-sensitize cancer cells to apoptosis and other treatments.
One method involves using small molecule inhibitors designed to directly bind to and inactivate survivin. These molecules disrupt its anti-apoptotic and cell division-promoting functions. Another strategy employs antisense oligonucleotides or RNA interference (RNAi) to specifically reduce survivin protein production within cancer cells. These genetic approaches target the messenger RNA (mRNA) for survivin synthesis, leading to its degradation and decreased protein levels.
Immunotherapy approaches are also being investigated, where the body’s own immune system is trained to recognize and attack cells overexpressing survivin. This might involve vaccines or adoptive cell therapies. While these therapeutic strategies show promise, challenges remain, including ensuring specificity for cancer cells. Targeting survivin represents a significant avenue in the development of more effective cancer treatments.