The HIF3A gene, encoding the hypoxia-inducible factor 3 alpha (HIF-3α), plays a critical role in the cellular response to hypoxia. Below is an expanded summary based on various aspects of the HIF3A gene, including other connected genes, implications in aging and disease, drug interactions, and involved pathways.

### 1. Associated Genes
HIF3A is associated with several other genes related to the hypoxia response and cellular signaling pathways:

- **HIF1A (Hypoxia-inducible factor 1-alpha)**: A major regulator of oxygen homeostasis and a direct target for HIF3A regulation.
- **HIF2A (Hypoxia-inducible factor 2-alpha)**: Another member of the hypoxia-inducible factor family that can form heterodimers with HIF1A or HIF3A.
- **VHL (Von Hippel-Lindau tumor suppressor)**: This gene is involved in the degradation of hypoxia-inducible factors, including HIF1A and HIF2A, via the ubiquitin-proteasome pathway.
- **EPAS1 (Endothelial PAS domain protein 1)**: Sometimes referred to as HIF2A, it is related to various aspects of the hypoxic response and is implicated in several diseases.

### 2. Aging and Age-related Diseases
Research has indicated that HIF3A may play a role in age-related conditions:

- **Aging**: The expression of HIF3A has been found to be altered in various tissues with age, suggesting that it may modulate hypoxia responses as part of the aging process.
- **Age-related diseases**: HIF3A has been implicated in conditions such as:
  - **Cardiovascular diseases**: Due to its role in the cardiorespiratory system, alterations in HIF3A signaling may contribute to heart diseases as individuals age.
  - **Cancer**: Given its role in inhibiting angiogenesis, dysregulation of HIF3A can affect tumor growth and progression, potentially linking it to age-related cancer risks.
  - **Neurodegenerative diseases**: Hypoxia is a stressor for the brain, and HIF3A may modulate responses that relate to neuron survival and apoptosis in aging.

### 3. Drug Interactions
There is currently limited information on specific drugs that interact directly with HIF3A; however, the following classes may be relevant due to their actions on the hypoxic response:

- **HIF stabilizers**: Compounds developed to stabilize HIF proteins can indirectly interact with HIF3A pathways.
- **Anticancer drugs**: Some drugs targeting tumor hypoxia may affect the expression and activity of HIF3A, as it regulates angiogenesis.
- **Metabolic modulators**: Certain medications that affect metabolic pathways (like metformin) may influence HIF signaling cascades involving HIF3A as part of their mechanisms.

### 4. Pathways and Biological Processes
HIF3A is involved in several critical biological pathways and processes:

- **Hypoxia-Inducible Factor Signaling Pathway**: Directly participates in the cellular response to low oxygen levels, regulating gene expression related to adaptive responses.
- **Angiogenesis**: Acts as an inhibitor in hypoxic environments, particularly in ocular tissues such as the cornea.
- **Development of the cardiorespiratory system**: Critical in regulating genes involved in  vascular development and function.
- **Regulation of Apoptosis**: HIF3A may help modulate cell survival mechanisms under hypoxic conditions.

In conclusion, HIF3A is an important gene with multifaceted roles in the cellular response to hypoxia, and its implications in aging, associated diseases, and interactions with drug therapies merit further research for clinical applications and therapeutic strategies.