International journal of molecular sciences

Molecular Processes That May Promote Cancer Spread in Older Tumor Environments

Updated

Abstract

Aging-related processes may contribute to cancer metastasis through multiple biological mechanisms.

  • The accumulation of senescent cells in the tumor microenvironment releases factors that remodel the extracellular matrix and activate pathways associated with metastasis.
  • Chronic low-grade inflammation in older adults attracts immunosuppressive cells, hindering the immune system's ability to detect and eliminate cancer cells.
  • Aged tumor microenvironments experience significant changes in blood vessel formation and metabolism, which may support the emergence of aggressive cancer clones.
  • Molecular aging indicators, such as telomere shortening and oxidative DNA damage, are associated with genetic instability that favors metastasis in older cancer patients.
  • Potential therapeutic strategies discussed include targeting senescent cells, reducing inflammation, rejuvenating the immune system, and metabolic interventions.

Simplified

Key numbers

2–4 times
VEGF-A Expression Increase
VEGF-A expression increases in aged tissues
20–40%
Functional Vessel Density Decrease
Functional vessel density decreases in aged tissues
30–50%
Permeability Increase
Vascular permeability increases in aged tissues

Full Text

What this is

  • This review examines how aging alters the tumor microenvironment (TME) to promote cancer metastasis.
  • It discusses the roles of cellular senescence, chronic inflammation, immune decline, ECM changes, and abnormal angiogenesis.
  • Understanding these mechanisms is crucial as cancer incidence rises among older adults, necessitating age-specific therapeutic strategies.

Essence

  • Aging transforms the TME, fostering conditions that enhance cancer metastasis through immune dysfunction, inflammation, and ECM remodeling.

Key takeaways

  • Cellular senescence in the aged TME releases pro-inflammatory cytokines and growth factors that promote tumor invasion and metastasis.
  • Chronic inflammation in aging tissues activates pathways that support tumor growth while suppressing immune responses, creating a permissive environment for metastasis.
  • Altered ECM properties in aged tissues, including increased stiffness and abnormal angiogenesis, facilitate cancer cell migration and survival, complicating treatment responses.

Caveats

  • The review relies on preclinical studies and age-mismatched models, which may limit the applicability of findings to human aging.
  • Some insights are derived from in vitro systems that may not accurately reflect the complexities of the TME in older adults.
  • Immunotherapy effectiveness in older patients is limited due to age-related immune declines, necessitating innovative rejuvenation strategies.

Definitions

  • senescence-associated secretory phenotype (SASP): A phenotype characterized by senescent cells releasing pro-inflammatory cytokines and growth factors that promote tumor progression.
  • inflammaging: Chronic low-grade inflammation associated with aging that contributes to various age-related diseases, including cancer.

Simplified

Funding

Competing interests

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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